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Journal articles on the topic 'Electrodes'
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Yashiro, Yusuke, Michitaka Yamamoto, Yoshihiro Muneta, Hiroshi Sawada, Reina Nishiura, Shozo Arai, Seiichi Takamatsu, and Toshihiro Itoh. "Comparative Studies on Electrodes for Rumen Bacteria Microbial Fuel Cells." Sensors 23, no. 8 (April 21, 2023): 4162. http://dx.doi.org/10.3390/s23084162.
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Microbial fuel cells (MFCs) using rumen bacteria have been proposed as a power source for running devices inside cattle. In this study, we explored the key parameters of the conventional bamboo charcoal electrode in an attempt to improve the amount of electrical power generated by the microbial fuel cell. We evaluated the effects of the electrode’s surface area, thickness, and rumen content on power generation and determined that only the electrode’s surface area affects power generation levels. Furthermore, our observations and bacterial count on the electrode revealed that rumen bacteria concentrated on the surface of the bamboo charcoal electrode and did not penetrate the interior, explaining why only the electrode’s surface area affected power generation levels. A Copper (Cu) plate and Cu paper electrodes were also used to evaluate the effect of different electrodes on measuring the rumen bacteria MFC’s power potential, which had a temporarily higher maximum power point (MPP) compared to the bamboo charcoal electrode. However, the open circuit voltage and MPP decreased significantly over time due to the corrosion of the Cu electrodes. The MPP for the Cu plate electrode was 775 mW/m2 and the MPP for the Cu paper electrode was 1240 mW/m2, while the MPP for bamboo charcoal electrodes was only 18.7 mW/m2. In the future, rumen bacteria MFCs are expected to be used as the power supply of rumen sensors.
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Zimmer, Philip, Christian Stolze, Simon Muench, Xiao Weisheng, Steffi Stumpf, Stephanie Hoeppener, Martin D. Hager, and Ulrich S. Schubert. "Percolation Investigation of Polymer-Based Battery Electrodes and Its Influence on Capacity Utilization." ECS Meeting Abstracts MA2024-02, no. 25 (November 22, 2024): 2048. https://doi.org/10.1149/ma2024-02252048mtgabs.
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Our oral presentation will offer a comprehensive exploration of the intricate dynamics governing organic radical battery electrodes, focusing on the percolation phenomena and its consequential influence on capacity utilization. Our latest investigations center around quantifying the role of conducting additives, notably the widely employed spherical SuperP® (SP), within a composite electrode based on poly(2,2,6,6-tetramethyl-4-piperinidyl-N-oxylmethacrylate) (PTMA). We recently reported a comprehensive study on the percolation investigation of SP in such composite electrodes in the Chemical Engineering Journal 2023, 477, 146882. This quantitative analysis of the conducting additive in organic battery electrodes emphasizes the critical balance required for optimal electrode composition in industrial applications. Based on the percolation theory we experimentally investigate various electrode compositions and identify a pivotal phase transition at 8 wt.% SP, which is effectively transforming the electrode's behavior from dielectric to conducting. To provide a comprehensive understanding, we incorporated a series of experimental analyses. The investigation begins with a detailed exploration of permittivities, shedding light on the dielectric properties of the composite electrode. Dielectric losses are scrutinized, providing insights into energy dissipation mechanisms within the electrode. Moreover, the characterization shows that the electrode exhibits so called epsilon-negative properties, which is commonly reported in literature for polymer/nanomaterial composites. However, a resonance type behavior of the permittivity measured at a relatively low frequency could not be assigned to any literature findings yet. Furthermore, morphological assessments through scanning electron microscopy offer a visual, qualitative validation of the established conducting percolation paths within the PTMA-based composite electrode. To the best of our knowledge, we are the first to apply distribution of relaxation times (DRT) analysis to organic radical battery electrodes, validating the hopping-type conduction mechanism for the dielectric electrodes below percolation threshold as well as assigning the conduction above percolation threshold to the SP phase. The electrochemical characterization of the percolation phase transition's impact on the electrode’s capacity utilization was investigated in both coin cells (two-electrode setup) and Swagelok cells (three-electrode setup) via galvanostatic cycling experiments. These electrochemical analyses not only validate the percolation-induced shift in behavior but also provide insights into the charge storage capabilities of several electrode compositions, which provides a basis for electrode optimization. Furthermore, the cycling experiments elucidate the electrochemical performance variations when employing two-electrode setups as opposed to three-electrode setups. Key findings underscore a direct correlation between the optimal electrode composition for enhanced capacity utilization and the observed percolation phase transition. Electrodes falling below the percolation threshold exhibit charge storage characteristics close to zero, primarily due to elevated ohmic overpotentials. In contrast, electrodes exceeding the threshold demonstrate a rapid saturation in capacity utilization, signifying the intricate interplay between conducting paths and efficient accessibility of redox centers within battery electrodes. Additionally, our findings introduce the possible application of impedance spectroscopy (IS) measurements as a preliminary electrode characterization step. This new approach not only offers valuable insights into the charge-discharge dynamics of organic radical battery electrodes but also enables general electrode composition optimization prior to laborious cell assembly and time-consuming battery cycling experiments. Furthermore, this work may be used as basis for a potential pre-quality control tool for electrodes in a high-throughput production in an industrial setting. Considering the graphical abstract, concentration changes could be identified before cell assembly. Additionally, the impact on cell performance due to the concentration changes may be estimated. By integrating IS into the production process, we envision real-time monitoring and adjustment during large-scale manufacturing processes, ensuring consistent electrodes with optimized performance. Figure 1
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Asl, Sara Nazari, Frank Ludwig, and Meinhard Schilling. "Noise properties of textile, capacitive EEG electrodes." Current Directions in Biomedical Engineering 1, no. 1 (September 1, 2015): 34–37. http://dx.doi.org/10.1515/cdbme-2015-0009.
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AbstractThe rigid surface of the conventional PCB-based capacitive electrode produces an undefined distance between the skin and the electrode surface. Therefore, the capacitance introduced by them is uncertain and can vary from electrode to electrode due to their different positions on the scalp. However, textile electrodes which use conductive fabric as electrode surfaces, are bendable over the scalp. Therefore, it provides a certain value of the capacitance which is predictable and calculable accurately if the effective distance to the scalp surface can be determined. In this paper noise characteristics of textile electrodes with different fabric sizes as electrode’s surface and capacity calculations related to each size are presented to determine the effective distances for each electrode size.
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Khan, Waris N., and Rahul Chhibber. "Experimental investigation on dissimilar weld between super duplex stainless steel 2507 and API X70 pipeline steel." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 235, no. 8 (May 4, 2021): 1827–40. http://dx.doi.org/10.1177/14644207211013056.
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This work investigates the microstructure and mechanical properties of 2507 super duplex stainless steel and API X70 high strength low alloy steel weld joint. This joint finds application in offshore hydrocarbon drilling riser and oil–gas pipelines. Coated shielded metal arc welding electrodes have been designed and extruded on 309L filler and their performance compared with a commercial austenitic electrode E309L. Filler 309L solidifies in ferrite-austenite (F-A) mode with a resultant microstructure comprising skeletal ferrites with austenite distributed in the interdendritic region. Results of tensile and impact tests indicate that weld fabricated with laboratory-developed electrodes has higher ductility and impact energy than the commercial electrode. The tensile strength and weld hardness of commercial electrodes are superior. The laboratory-made electrode’s microhardness is lower than the commercial electrodes, making the former less prone to failure. An alternative welding electrode coating composition has been suggested through this work and found to be performing satisfactorily and comparable to the commercially available electrodes.
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Al Hajji Safi, Maria, Andrea Bourke, D. Noel Buckley, and Robert P. Lynch. "(Invited) Insights from Cyclic Voltammetry into Active Sites on Carbon Electrodes and Their Importance in Vanadium Flow Batteries and Other Electrochemical Applications." ECS Meeting Abstracts MA2024-02, no. 69 (November 22, 2024): 4837. https://doi.org/10.1149/ma2024-02694837mtgabs.
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Flow battery technology is uniquely positioned to fill the niche of long duration energy storage that will be needed to enhance grid reliability and power quality. Vanadium Flow Batteries (VFBs) and other flow battery technologies use carbon as their electrodes. The behaviour of carbon as an electrode is complex and there is considerable variation in the literature regarding the kinetics of flow battery reactions at carbon electrodes. The electrochemical response of a carbon electrode towards redox reactions is known to be improved after electrochemical treatments. For the past decade we have investigated the effect of electrochemical treatment on the electrode activity of carbon towards vanadium redox reactions. We have reported that cathodic treatment in acidic solution enhances the kinetics of the positive (VIV-VV) electrode in VFBs but inhibits the kinetics of the negative (VII-VIII) electrode, while anodic treatment inhibits the kinetics of the positive electrode but enhances the kinetics of the negative electrode1-3. We also showed that the activity of carbon-based material is strongly dependent on the surface history, and in particular on the most positive and the most negative potential used to treat an electrode4. In this presentation, we report some interesting results from our investigations of carbon electrode pretreatment in H2SO4. The cyclic voltammetry behavior which we observe shows a remarkable correlation with kinetics measurements in vanadium-containing electrolytes. We believe that our results provide a novel method of investigating the behavior of active sites on carbon electrodes. This is particularly important in the context of flow battery electrodes but may also, in a much broader context, provide a route to understanding the electrocatalytic behavior of carbon electrodes in many other applications. References. A. Bourke, M. A. Miller, R. P. Lynch, X. Gao, J. Landon, J. S. Wainright, R. F. Savinell and D. N. Buckley, J. Electrochem. Soc. 163, A5097 (2016). A. Bourke, M. A. Miller, R. P. Lynch, J. S. Wainright, R. F. Savinell and D. N. Buckley, J. Electrochem. Soc., 162, A1547 (2015). M. A. Miller, A. Bourke, N. Quill, J. S. Wainright, R. P. Lynch, D. N. Buckley and R. F. Savinell, J. Electrochem. Soc., 163, A2095 (2016). M. Al Hajji Safi, A. Bourke, D. N. Buckley, R. P. Lynch, ECS Trans., 109, 67-84 (2022).
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Rondou, Noah, Philippe M. Vereecken, and Martijn J. W. Blom. "Surface-Limited Electrochemical Reactions for the Characterization of Mass Transport in Nanoporous Electrodes." ECS Meeting Abstracts MA2024-02, no. 22 (November 22, 2024): 1844. https://doi.org/10.1149/ma2024-02221844mtgabs.
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Minimizing transport losses in (nano)porous electrodes is essential to many electrochemical applications such as electrolyzers, fuel cells, high-power density batteries. Often diffusion is the dominating mechanism that limits mass transport in these electrodes with very large surface areas. Electrochemical methods that characterize diffusion in porous electrodes, such as electrochemical impedance spectroscopy and scanning electrochemical microscopy, are limited in their use due to complex data interpretation and/or stringent infrastructure requirements. We have developed a novel method that utilizes a surface-limited reaction in a rotating disk setup that allows for the fast and straightforward characterization of effective diffusion coefficients in nanoporous electrodes, as well as estimation of their roughness. Surface-limited electrochemical reactions, such as underpotential deposition (UPD), are commonly used to characterize the electrochemical surface area of porous electrodes. However, it has been shown that in nanoporous electrodes these processes can run into mass transport limitations, taking minutes to reach completion1,2. We utilize this effect in a rotating disk electrode setup, where it results in a characteristic current transient (Fig. 1a). An analytical model was developed to describe these current transients and extract performance parameters. Different sections of the current transient can be utilized to gain information on the porous electrode as illustrated in Fig. 1a. Besides the effective diffusion coefficient, determining the roughness of the porous electrode, the uniformity of the external mass transport resistance, and the bulk diffusion coefficient are possible. The tortuosity can then be determined from the bulk diffusion coefficient, porosity, and the effective diffusion coefficient. Further analysis of the analytical model also shows the possibility of electrochemically mapping the distribution of active sites in porous electrodes. The methodology was tested experimentally on a platinum nanomesh electrode3 utilizing Cu UPD. An SEM image of a cross-section of the electrode is given in Fig. 1b. The nanomesh electrode's intrinsic high volumetric surface area (~ 30 m²/cm³) leads for certain to mass transport limitations for the Cu UPD process even for Cu2+ concentrations up to 0.8 mol/L. This combined with the uniformity of the electrode thickness allows it to be the ideal model system to verify the analytical model. The methodology was validated for different reaction conditions by comparing the tortuosity which was found to remain constant. The applicability of our method to porous electrodes in general will be discussed. References Y. Liu, S. Bliznakov, and N. Dimitrov, J. Phys. Chem. C, 113, 12362–12372 (2009). E. E. Levin et al., Nanomaterials, 13 (2023). S. P. Zankowski and P. M. Vereecken, ACS applied materials & interfaces, 10, 44634–44644 (2018). Figure 1
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Zhang, Wenjie, Yongqi Liu, Zhouyang Qin, Lingxiao Yu, Jiabiao Lian, Zhanliang Tao, and Zheng-Hong Huang. "Flexible Carbon Fiber/SnO2@rGO Electrode with Long Cyclability for Lithium-Ion Batteries." Batteries 10, no. 12 (November 25, 2024): 412. http://dx.doi.org/10.3390/batteries10120412.
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Flexible electrodes are highly desirable for next-generation wearable lithium-ion batteries. To achieve high-capacity flexible electrode materials, SnO2 with high theoretical capacity has been introduced into electrodes and shows promising capacity. However, the electrodes are still confronted with major challenges in terms of inferior rate capability and cycling stability, which are caused by large volume changes of SnO2 during the lithiation/delithiation process. Here, we adopt an adsorption assembly strategy to fabricate a flexible carbon fiber/SnO2@rGO electrode that effectively stabilizes the volume changes of SnO2 and enhances the charge transport kinetics in electrodes. The sandwich-like structure endows the electrode’s high flexibility and succeeds in improving both rate capability and cycling stability. The flexible carbon fiber/SnO2@rGO electrode delivers a high capacity of 453 mAh g−1 at 50 mA g−1 and outstanding capacity retention of 88% after 1000 cycles at 2 A g−1.
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Aoyagi, Seiji, Masaru Kawanishi, and Daiichiro Yoshikawa. "Multiaxis Capacitive Force Sensor and its Measurement Principle Using Neural Networks." Journal of Robotics and Mechatronics 18, no. 4 (August 20, 2006): 442–49. http://dx.doi.org/10.20965/jrm.2006.p0442.
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We propose a multiaxis capacitive force sensor consisting of one movable upper electrode on a plate and fixed lower electrodes on a substrate. The plate moves both vertically and horizontally when force is applied, and capacitance between upper and lower electrodes changes. This sensor uses the main electrical field between two directly facing electrodes and the fringe electrical field between diagonally opposed electrodes, making capacitance difficult to analyze. We simulated changes in nonlinear capacitance based on the upper electrode’s movement using the finite element method (FEM) and proved that capacitance is a function of the upper electrode’s displacement. We used a neural network to calculate the upper electrode’s displacement from capacitance. The neural network operates appropriately and calculated displacement error is within 0.5% of the full range. We proposed fabricating a practical force sensor consisting of planar capacitors making it compatible with surface micromachining and not requiring 3-D bulk micromachining, which simplifies fabrication, making it economical.
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Tanumihardja, Esther, Douwe S. de Bruijn, Rolf H. Slaats, Wouter Olthuis, and Albert van den Berg. "Monitoring Contractile Cardiomyocytes via Impedance Using Multipurpose Thin Film Ruthenium Oxide Electrodes." Sensors 21, no. 4 (February 18, 2021): 1433. http://dx.doi.org/10.3390/s21041433.
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A ruthenium oxide (RuOx) electrode was used to monitor contractile events of human pluripotent stem cells-derived cardiomyocytes (hPSC-CMs) through electrical impedance spectroscopy (EIS). Using RuOx electrodes presents an advantage over standard thin film Pt electrodes because the RuOx electrodes can also be used as electrochemical sensor for pH, O2, and nitric oxide, providing multisensory functionality with the same electrode. First, the EIS signal was validated in an optically transparent well-plate setup using Pt wire electrodes. This way, visual data could be recorded simultaneously. Frequency analyses of both EIS and the visual data revealed almost identical frequency components. This suggests both the EIS and visual data captured the similar events of the beating of (an area of) hPSC-CMs. Similar EIS measurement was then performed using the RuOx electrode, which yielded comparable signal and periodicity. This mode of operation adds to the versatility of the RuOx electrode’s use in in vitro studies.
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Rashedul, Islam Md, Yan Zhang, Kebing Zhou, Guoqian Wang, Tianpeng Xi, and Lei Ji. "Influence of Different Tool Electrode Materials on Electrochemical Discharge Machining Performances." Micromachines 12, no. 9 (September 7, 2021): 1077. http://dx.doi.org/10.3390/mi12091077.
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Electrochemical discharge machining (ECDM) is an emerging method for developing micro-channels in conductive or non-conductive materials. In order to machine the materials, it uses a combination of chemical and thermal energy. The tool electrode’s arrangement is crucial for channeling these energies from the tool electrode to the work material. As a consequence, tool electrode optimization and analysis are crucial for efficiently utilizing energies during ECDM and ensuring machining accuracy. The main motive of this study is to experimentally investigate the influence of different electrode materials, namely titanium alloy (TC4), stainless steel (SS304), brass, and copper–tungsten (CuW) alloys (W70Cu30, W80Cu20, W90Cu10), on electrodes’ electrical properties, and to select an appropriate electrode in the ECDM process. The material removal rate (MRR), electrode wear ratio (EWR), overcut (OC), and surface defects are the measurements considered. The electrical conductivity and thermal conductivity of electrodes have been identified as analytical issues for optimal machining efficiency. Moreover, electrical conductivity has been shown to influence the MRR, whereas thermal conductivity has a greater impact on the EWR, as characterized by TC4, SS304, brass, and W80Cu20 electrodes. After that, comparison experiments with three CuW electrodes (W70Cu30, W80Cu20, and W90Cu10) are carried out, with the W70Cu30 electrode appearing to be the best in terms of the ECDM process. After reviewing the research outcomes, it was determined that the W70Cu30 electrode fits best in the ECDM process, with a 70 μg/s MRR, 8.1% EWR, and 0.05 mm OC. Therefore, the W70Cu30 electrode is discovered to have the best operational efficiency and productivity with performance measures in ECDM out of the six electrodes.
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Zhang, Rui, Zhiqiang Tian, Wenxiong Xi, and Dongjing He. "Discharge Characteristics and System Performance of the Ablative Pulsed Plasma Thruster with Different Structural Parameters." Energies 15, no. 24 (December 12, 2022): 9389. http://dx.doi.org/10.3390/en15249389.
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Under the given initial discharge energy level, altering the electrode structural parameters of the Ablative Pulse Plasma Thruster (APPT) is an effective way to improve the performance of the thruster. The purpose of this study is to reveal the underlying mechanism of the effect of changing the electrode structure parameters on the performance of the APPT system and to offer targeted support for researchers to optimize the design of APPT structure. With rectangular and tongue-shaped electrode configurations at various electrode flare angles, electrode lengths, and electrode spacings, the discharge characteristics, propellant ablation characteristics, and thruster performance of the APPT are systematically investigated. The underlying mechanism of how changing the electrode’s configuration parameter affects the performance of the thruster is identified by fitting and predicting the parameters of the APPT discharge circuit and system performance under various operating conditions. The results show that using tongue-shaped electrodes is more effective than using rectangular electrodes in terms of enhancing the inductive gradient of the electrodes, transferring more energy to the discharge channel, and increasing the squared integral value of the discharge current. As a result, the tongue-shaped electrode APPT performs better than the APPT with rectangular electrodes, as a consequence. The thruster’s performance can be enhanced for the same electrode configuration by increasing the electrode flare angle within a certain angle range; however, the improvement is extremely limited. Additionally, in the case of small electrode spacing, increasing the electrode flare angle can enhance the thruster’s performance more effectively.
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Garba, Elhuseini, Ahmad Majdi Abdul-Rani, Nurul Azhani Yunus, Abdul Azeez Abdu Aliyu, Iqtidar Ahmed Gul, Md Al-Amin, and Ruwaida Aliyu. "A Review of Electrode Manufacturing Methods for Electrical Discharge Machining: Current Status and Future Perspectives for Surface Alloying." Machines 11, no. 9 (September 12, 2023): 906. http://dx.doi.org/10.3390/machines11090906.
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In electrical discharge machining (EDM), the tool electrode is one of the substantial components of the system, and it ensures the success or failure of the EDM process. The electrode’s role is to conduct electrical charges and erode the workpiece to the desired shape. Different electrode materials have different impacts on machining. Certain electrode materials remove metal quickly but wear out rapidly, while others degrade slowly but the material removal is too slow. The choice of the electrode has an influence on both the mechanical properties, such as metal removal rate (MRR), wear rate, surface finish, surface modification and machinability, and the electrical properties, such as sparking initiation, time lag, gap contamination and process stability. There are factors to consider when fabricating an electrode, which include the type of workpiece materials, the metallurgical alloying of the materials, the choice of fabrication techniques, the intended use of the electrode, and material cost. Considerable challenges in EDM electrode fabrication have been reported, which include excessive tool wear for green compact electrodes, high toughness for sintered electrodes, and poor rigidity for additively manufactured electrodes. To address these issues, researchers have explored different manufacturing methods, such as casting, conventional machining, electrodeposition, powder metallurgy and additive manufacturing. In this paper, the various techniques attempted and adopted in EDM electrode manufacturing are analyzed and discussed. This paper also sought to give insight into EDM, its various forms, the dielectric fluid’s properties, EDM electrode’s size and shape, the effects of the electrode on the EDM process, material removal, electrode wear, present technologies for electrode fabrication, and the limitations of these technologies. Finally, directions for future research are highlighted.
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Carvalho, Daniel, Sandra Marques, Giorgia Siqueira, Armando Ferreira, João Santos, Dulce Geraldo, Cidália R. Castro, Ana V. Machado, Filipe Vaz, and Cláudia Lopes. "Enhancing the Longevity and Functionality of Ti-Ag Dry Electrodes for Remote Biomedical Applications: A Comprehensive Study." Sensors 23, no. 19 (October 8, 2023): 8321. http://dx.doi.org/10.3390/s23198321.
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This study aims to evaluate the lifespan of Ti-Ag dry electrodes prepared using flexible polytetrafluoroethylene (PTFE) substrates. Following previous studies, the electrodes were designed to be integrated into wearables for remote electromyography (EMG) monitoring and electrical stimulation (FES) therapy. Four types of Ti-Ag electrodes were prepared by DC magnetron sputtering, using a pure-Ti target doped with a growing number of Ag pellets. After extensive characterization of their chemical composition and (micro)structural evolution, the Ti-Ag electrodes were immersed in an artificial sweat solution (standard ISO-3160-2) at 37 °C with constant stirring. Results revealed that all the Ti-Ag electrodes maintained their integrity and functionality for 24 h. Although there was a notable increase in electrical resistivity beyond this timeframe, the acquisition and transmission of (bio)signals remained viable for electrodes with Ag/Ti ratios below 0.23. However, electrodes with higher Ag content (Ag/Ti = 0.31) became insulators after 7 days of immersion due to excessive Ag release into the sweat solution. This study concludes that higher Ag/Ti atomic ratios result in heightened corrosion processes on the electrode’s surface, consequently diminishing their lifespan despite the advantages of incorporating Ag into their composition. This research highlights the critical importance of evaluating electrode longevity, especially in remote biomedical applications like smart wearables, where electrode performance over time is crucial for reliable and sustained monitoring and stimulation.
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Rahman, Fathur, Aulia Ghifari Nurlis, Damar Rastri Adhika, and Suprijanto. "Fabrication and Evaluation of Carrageenan Based Bioplastic with Graphite and Ag-Nanoparticles Addition as Flexible Electrode for EMG Signal Measurement." Materials Science Forum 1104 (November 10, 2023): 15–24. http://dx.doi.org/10.4028/p-hkf5fy.
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Electromyography (EMG) is a method for measuring muscle biopotential signals for monitoring muscle activity. Electrodes are placed on the skin to capture EMG signals from muscles underneath. The most common electrodes used in clinical EMG measurement are Ag/AgCl electrodes in the form of metal plates coated with electrode gel. Electrode gel enhances the contact between the electrode’s metal plate and the skin since it is essential for a good measurement signal quality. Meanwhile, flexible electrodes are made from flexible conductive materials that can be adjusted to the contour of the skin surface; therefore, they can improve the measured biopotential signal quality. This study developed a carrageenan-based bioplastic with the addition of graphite and silver nanoparticles (AgNP) hybrid as a flexible electrode for EMG signal measurement. Fabrication of graphite and AgNP hybrid starts with the functionalization of the graphite powder in a mixture of HNO3 and H2SO4. Next, AgNPs were added using the electrochemical method by utilizing SnCl2 and functionalized graphite powder to form an Ag-Sn/Graphite (Graphite-AgNPs) hybrid conductive material. In order to incorporate conductive materials into bioplastic, the Graphite-AgNPs hybrid conductive material is then mixed into the carrageenan-based bioplastic mixture. It is found that 25% w/w addition of these conductive materials already gives good electrical conductivity. The best electrical conductivity value was determined by varying several conductive material types and concentrations. Finally, the EMG signal was measured with the bioplastic flexible electrodes, and the performance was compared with the commercial Ag/AgCl electrodes.
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Cen, Chao, and Xinhua Chen. "The Electrode Modality Development in Pulsed Electric Field Treatment Facilitates Biocellular Mechanism Study and Improves Cancer Ablation Efficacy." Journal of Healthcare Engineering 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/3624613.
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Pulsed electric field treatment is now widely used in diverse biological and medical applications: gene delivery, electrochemotherapy, and cancer therapy. This minimally invasive technique has several advantages over traditional ablation techniques, such as nonthermal elimination and blood vessel spare effect. Different electrodes are subsequently developed for a specific treatment purpose. Here, we provide a systematic review of electrode modality development in pulsed electric field treatment. For electrodes invented for experiment in vitro, sheet electrode and electrode cuvette, electrodes with high-speed fluorescence imaging system, electrodes with patch-clamp, and electrodes with confocal laser scanning microscopy are introduced. For electrodes invented for experiment in vivo, monopolar electrodes, five-needle array electrodes, single-needle bipolar electrode, parallel plate electrodes, and suction electrode are introduced. The pulsed electric field provides a promising treatment for cancer.
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Xia, Jie, Fan Zhang, Luxi Zhang, Zhen Cao, Shurong Dong, Shaomin Zhang, Jikui Luo, and Guodong Zhou. "Magnetically Compatible Brain Electrode Arrays Based on Single-Walled Carbon Nanotubes for Long-Term Implantation." Nanomaterials 14, no. 3 (January 23, 2024): 240. http://dx.doi.org/10.3390/nano14030240.
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Advancements in brain–machine interfaces and neurological treatments urgently require the development of improved brain electrodes applied for long-term implantation, where traditional and polymer options face challenges like size, tissue damage, and signal quality. Carbon nanotubes are emerging as a promising alternative, combining excellent electronic properties and biocompatibility, which ensure better neuron coupling and stable signal acquisition. In this study, a new flexible brain electrode array based on 99.99% purity of single-walled carbon nanotubes (SWCNTs) was developed, which has 30 um × 40 um size, about 5.1 kΩ impedance, and 14.01 dB signal-to-noise ratio (SNR). The long-term implantation experiment in vivo in mice shows the proposed brain electrode can maintain stable LFP signal acquisition over 12 weeks while still achieving an SNR of 3.52 dB. The histological analysis results show that SWCNT-based brain electrodes induced minimal tissue damage and showed significantly reduced glial cell responses compared to platinum wire electrodes. Long-term stability comes from SWCNT’s biocompatibility and chemical inertness, the electrode’s flexible and fine structure. Furthermore, the new brain electrode array can function effectively during 7-Tesla magnetic resonance imaging, enabling the collection of local field potential and even epileptic discharges during the magnetic scan. This study provides a comprehensive study of carbon nanotubes as invasive brain electrodes, providing a new path to address the challenge of long-term brain electrode implantation.
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Wang, Zhaoshun, Zeyuan Li, Harsh Agarwal, Ryan Stephens, and Ming Tang. "Optimizing Electronic Conductivity to Improve the Thick Battery Electrode Performance for Lithium-Ion Batteries." ECS Meeting Abstracts MA2024-01, no. 5 (August 9, 2024): 709. http://dx.doi.org/10.1149/ma2024-015709mtgabs.
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Thick battery electrode designs have attracted broad interest from the lithium-ion battery industry because they represent a promising approach to significantly increase the battery energy density at the cell level and reduce the materials and manufacturing cost at the same time. However, increasing the electrode thickness also increases the ionic and electronic transport distance, leading to inferior rate performance. Previous studies on improving thick electrode performance have mainly focused on the design and fabrication of three-dimensional electrode architecture (e.g. electrodes with low tortuosity porous channels) to facilitate ionic transport. On the other hand, how the electronic conductivity should be optimized for thick electrodes has received less attention. Several existing studies report the effect of adding carbon nanotubes on the thick electrode performance, but it is not clear how the results could be generalized to other types of conductive additives. In this study, we ask the questions: how does the electrical conductivity affect the rate performance of thick electrodes, and are there general criteria for determining the optimal amount of conductive additives? Using LiFePO4 as a model system, we prepared a series of electrodes with different thickness and systematically varied electrical conductivity, which was achieved by adjusting the amount and ratios of two types of carbon additives, i.e. carbon black (C65) and vapor grown carbon nanofibers (VGCF). To obtain accurate readings of the intrinsic resistance of the LiFePO4 composite electrodes, a thickness extrapolation method was applied to remove the contact resistance at the Al/LiFePO4 and probe/LiFePO4 interfaces. We discovered that while 2 wt% C65 is sufficient for thin electrodes (<50 μm), at least 5 wt% C65 is required to maximize the rate performance of thicker electrodes (>100 μm), see Figure 1a&b. Further study reveals the existence of a critical electrical conductivity : the electrode’s rate capability increases with the conductivity at but saturates above (Figure 1c). The optimal amount of conductive additive is thus determined by . For electrodes thicker than 100 μm, we discovered that is independent of electrode thickness and comparable to the ionic conductivity of the electrodes. For thinner electrodes, however, increases monotonically with the electrode thickness L. We show that this phenomenon could be explained by the competition between three types of resistance present in the electrode: charge transfer (RCT), electrical (Relec) and ionic (Rion) resistances. Our prediction of the curve agrees with experiments, which could serve as a general guidance to the optimization of conductive additives for thick electrodes. Our study also reveals that the critical electrical conductivity could be most effectively achieved for thick electrodes via a combination of C65 and VGCF thanks to their complementary morphologies. While the fiber-shaped VGCF provides long-range pathways for electron conduction across the electrodes, the contact between particulate C65 and active materials facilitates the short-range electrical wiring. As a result, only 3 wt% of hybrid additives (2wt% C65 + 1wt% VGCF) is needed to reach , as opposed to 5 wt% of C65 only. Figure 1. Rate performance of electrode with different carbon amount (a) Thin electrode and (b) 150 μm electrodes. (c) Rate capability of electrode with different electrical conductivity. Acknowledgement This work is supported by Shell International Exploration and Production, Inc. Reference Kuang, Y.; Chen, C.; Kirsch, D.; Hu, L., Thick Electrode Batteries: Principles, Opportunities, and Challenges. Advanced Energy Materials 2019, 9 (33). Ju, Z.; Zhang, X.; King, S. T.; Quilty, C. D.; Zhu, Y.; Takeuchi, K. J.; Takeuchi, E. S.; Bock, D. C.; Wang, L.; Marschilok, A. C.; Yu, G., Unveiling the dimensionality effect of conductive fillers in thick battery electrodes for high-energy storage systems. Applied Physics Reviews 2020, 7 (4). Tian, R.; Alcala, N.; O’Neill, S. J. K.; Horvath, D. V.; Coelho, J.; Griffin, A. J.; Zhang, Y.; Nicolosi, V.; O’Dwyer, C.; Coleman, J. N., Quantifying the Effect of Electronic Conductivity on the Rate Performance of Nanocomposite Battery Electrodes. ACS Appl Energ Mater 2020, 3 (3), 2966-2974. Lee, B.-S.; Wu, Z.; Petrova, V.; Xing, X.; Lim, H.-D.; Liu, H.; Liu, P., Analysis of Rate-Limiting Factors in Thick Electrodes for Electric Vehicle Applications. J Electrochem Soc 2018, 165 (3), A525-A533. Figure 1
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Velasco-Medina, Carlos, Patricio J. Espinoza-Montero, Marjorie Montero-Jimenez, José Alvarado, Mónica Jadán, Patricio Carrera, and Lenys Fernandez. "Development and Evaluation of Copper Electrodes, Modified with Bimetallic Nanoparticles, to be Used as Sensors of Cysteine-Rich Peptides Synthesized by Tobacco Cells Exposed to Cytotoxic Levels of Cadmium." Molecules 24, no. 12 (June 12, 2019): 2200. http://dx.doi.org/10.3390/molecules24122200.
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We report on two new electrochemical sensors which, coupled to differential pulse voltammetry, constitutes a useful tool for diagnosis of heavy metal pollution. The electrochemical sensors AgHgNf/Cu and the AgBiNf/Cu were obtained by deposition of bimetallic particles of AgHg or AgBi on copper electrodes covered with a Nafion (Nf) film, respectively. Micrographs of the electrode’s surface showed evenly scattered bimetallic particles, with an approximate diameter of 150 nm, embedded in the Nafion (Nf) film. In order to test the electrodes, the hydrogen evolution signal according to the Brdička reaction was measured for the determination of cysteine-rich peptides (CRp) produced by plants. To check the accuracy of the electrodes, real samples of Nicotiana tabacum cells exposed to cytotoxic levels of cadmium were tested. The AgHgNf/Cu electrode produced detection limits (DLs) of 0.088 µmol L−1 for Cysteine and 0.139µmol L−1 for Glutathione, while for the AgBiNf/Cu electrode DLs were 0.41 µmol L−1 for cysteine and 0.244 µmol L−1 for glutathione. Thus, the new electrodes could be a useful analytical electrochemical system very convenient for fieldwork. The electrodes were capable of direct, accurate, and sensitive detection of synthesized peptides, despite the complex matrix where the Nicotiana tabacum cells were grown.
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Goh, Andrew, David Roberts, Jesse Wainright, Narendra Bhadra, Kevin Kilgore, Niloy Bhadra, and Tina Vrabec. "Evaluation of Activated Carbon and Platinum Black as High-Capacitance Materials for Platinum Electrodes." Sensors 22, no. 11 (June 3, 2022): 4278. http://dx.doi.org/10.3390/s22114278.
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The application of direct current (DC) produces a rapid and reversible nerve conduction block. However, prolonged injection of charge through a smooth platinum electrode has been found to cause damage to nervous tissue. This damage can be mitigated by incorporating high-capacitance materials (HCM) (e.g., activated carbon or platinum black) into electrode designs. HCMs increase the storage charge capacity (i.e., “Q value”) of capacitive devices. However, consecutive use of these HCM electrodes degrades their surface. This paper evaluates activated carbon and platinum black (PtB) electrode designs in vitro to determine the design parameters which improve surface stability of the HCMs. Electrode designs with activated carbon and PtB concentrations were stressed using soak, bend and vibration testing to simulate destructive in vivo environments. A Q value decrease represented the decreased stability of the electrode–HCM interface. Soak test results supported the long-term Q value stabilization (mean = 44.3 days) of HCM electrodes, and both HCMs displayed unique Q value changes in response to soaking. HCM material choices, Carbon Ink volume, and application of Nafion™ affected an electrode’s ability to resist Q value degradation. These results will contribute to future developments of HCM electrodes designed for extended DC application for in vivo nerve conduction block.
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Chávez-Vera, Sara, David García-Bassoco, and Bernardo Antonio Frontana-Uribe. "Bismuth Film Electrodes: Characterization and Analytical Application." ECS Meeting Abstracts MA2024-01, no. 53 (August 9, 2024): 2856. http://dx.doi.org/10.1149/ma2024-01532856mtgabs.
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Bismuth film electrodes (BiFE) were first introduced more than two decades ago and have been regarded as a posible alternative to toxic traditional mercury electrodes, both for electro-synthesis and electro-analytical endeavors. However, despite all the associated benefits, there hasn’t been a proper characterization reported for this electrodes and their use is still limited. The present work shows the results of a physicochemical characterization of Bismuth film electrodes, as well as the application of BiFE for the detection and quantification of heavy metals (such as cadmium), which for years have been considered to be important pollutants and are toxic for humans and the environment at large; there for putting at risk the health of all organisms that come into contact with them. The analysis is carried out in a EtOH:H2O mixture at pH 5, simulating the matrix of a traditional mexican alcoholic beverage, Mezcal. The characterization includes: the calculation of the geometric area as well as the electro-active area of the electrode, the composition of the deposited film and it’s texture, and the electrical properties of the modified electrode. The analysis is carried out using Anodic Stripping Square Wave Voltammetry (ASSWV), this allows us to make use of the electrode’s ability to form strong interactions with the analyte, in a similar manner to that of mercury drop electrodes; along with the high sensitivity of this technique.
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Wang, Qing, Xiao Nan Zhang, Xiao Di Huo, Ren Hui Zhang, and Jian Feng Dai. "Study of Nanocrystalline ZnO and Zn2TiO4 Film Electrode with ZnPc Dye and PbS Quantum Dots Composite Sensitization." Advanced Materials Research 287-290 (July 2011): 2217–20. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.2217.
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Nanocrystalline ZnO and Zn2TiO4 porous film electrodes were prepared by sol-gel method and spin coating method, and the nanocrystalline porous films were characterized by XRD and SEM. Using ZnPc dye and PbS quantum dots as sensitizers. The nanocrystalline film electrodes of ZnO series and Zn2TiO4 series were prepared separately, and their absorption characteristics observed by UV-vis spectrophotometer. The results showed that ZnPc dye and PbS quantum dots could well sensitize the film electrodes, and the effect of ZnPc dye and PbS quantum dots composite sensitization was optimal. Then, the solar cells were fabricated. In simulation sunlight, the overall photoelectric conversion efficiency by Zn2TiO4/Q-PbS/ZnPc electrode increased by 22%, relative to the ZnO/Q-PbS/ZnPc electrode’s.
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Pope, Jackson, Chunmei Ban, Dakota Rodriguez, Donal P. Finegan, and Jackson Pope. "Title: Study of Structural Evolution of Silicon-Based Anodes in Lithium-Ion Batteries." ECS Meeting Abstracts MA2024-01, no. 1 (August 9, 2024): 174. http://dx.doi.org/10.1149/ma2024-011174mtgabs.
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The need for electrification across various sectors has led to increased demand for high-performance lithium-ion batteries (LIBs). Today’s commercial LIBs typically make use of a pure-graphite anode which offers long lifespans but a relatively meager capacity of 372 mAh/g. Silicon, by comparison, offers a theoretical capacity of 3600 mAh/g but generally suffers from short life spans due to numerous effects. Combining silicon and graphite active materials to form a composite anode can result in electrodes with improved capacities over pure-graphite systems and enhanced longevity over pure-silicon ones. However, introducing silicon to an otherwise stable graphite electrode can induce failure of the electrode partly due to the volumetric expansion/contraction that silicon experiences during lithiation/delithiation cycles. Understanding the morphological evolution of silicon particles in composite electrodes - particularly in a lithiated state - can yield a more comprehensive understanding of the interactions between the active materials which will contribute to the realization of anodes with improved capacities and lifespans. To date, characterizing lithiated silicon-containing anodes has been difficult owing to the reactivity of the lithiated materials and a lack of suitable methods to probe within an electrode’s bulk. In this work, we demonstrate recent successes in imaging lithiated silicon-composite and silicon oxide-composite electrodes via micro and nanoscale computed tomography (MicroCT, NanoCT) and electrochemical analysis to quantify (1) changes in particle size distributions over charge/discharge cycles, (2) lithium content in silicon particles as a function of depth from the electrode’s surface, (3) changes in particle morphology, and (4) electrode thickness. The development of this technique represents a significant step towards characterizing the physical behavior of silicon particles within electrodes without destroying the surrounding structures.
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Enache, Laura-Bianca, Veronica Anăstăsoaie, Liviu Birzan, Eleonora-Mihaela Ungureanu, Peng Diao, and Marius Enachescu. "Polyazulene-Based Materials for Heavy Metal Ion Detection. 2. (E)-5-(azulen-1-yldiazenyl)-1H-Tetrazole-Modified Electrodes for Heavy Metal Sensing." Coatings 10, no. 9 (September 8, 2020): 869. http://dx.doi.org/10.3390/coatings10090869.
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Azulene-based materials present very appealing properties for the preparation of advanced materials. They can be irreversibly electrooxidated, leading to polymers, which can be deposited on electrodes and modified. This paper shows several experiments concerning the preparation of modified electrodes based on (E)-5-(azulen-1-yldiazenyl)-1H-tetrazole (L). L has a tetrazole complexing unit, which can be attached to the electrode’s surface and recognized. L has been deeply characterized by electrochemical techniques. Complexing modified electrodes have been prepared and tested in different conditions. Functional modified electrodes based on L obtained by controlled potential electrolysis were examined by AFM and SEM to see the influences of charge and potential on the deposited polyz films’ morphologies. The modified electrodes prepared in different conditions have been tested for heavy metal ion sensing. The new azulene-based modified electrode demonstrated its feasibility for Pb ions analysis (detection limit of 5 × 10−8 M, and linear domain between 5 × 10−8 M and 10−6 M) and potential use in future applications for real water samples analysis.
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Slater, Lee, Dimitrios Ntarlagiannis, Nathan Yee, Michael O’Brien, Chi Zhang, and Kenneth H. Williams. "Electrodic voltages in the presence of dissolved sulfide: Implications for monitoring natural microbial activity." GEOPHYSICS 73, no. 2 (March 2008): F65—F70. http://dx.doi.org/10.1190/1.2828977.
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There is growing interest in the development of new monitoring strategies for obtaining spatially extensive data diagnostic of microbial processes occurring in the earth. Open-circuit potentials arising from variable redox conditions in the fluid local-to-electrode surfaces (electrodic potentials) were recorded for a pair of silver-silver chloride electrodes in a column experiment, whereby a natural wetland soil containing a known community of sulfate reducers was continuously fed with a sulfate-rich nutrient medium. Measurements were made between five electrodes equally spaced along the column and a reference electrode placed on the column inflow. The presence of a sulfate reducing microbial population, coupled with observations of decreasing sulfate levels, formation of black precipitate (likely iron sulfide),elevated solid phase sulfide, and a characteristic sulfurous smell, suggest microbial-driven sulfate reduction (sulfide generation) in our column. Based on the known sensitivity of a silver electrode to dissolved sulfide concentration, we interpret the electrodic potentials approaching [Formula: see text] recorded in this experiment as an indicator of the bisulfide [Formula: see text] concentration gradients in the column. The measurement of the spatial and temporal variation in these electrodic potentials provides a simple and rapid method for monitoring patterns of relative [Formula: see text] concentration that are indicative of the activity of sulfate-reducing bacteria. Our measurements have implications both for the autonomous monitoring of anaerobic microbial processes in the subsurface and the performance of self-potential electrodes, where it is critical to isolate, and perhaps quantify, electrochemical interfaces contributing to observed potentials.
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S. Rodrigues, Marco, Patrique Fiedler, Nora Küchler, Rui P. Domingues, Cláudia Lopes, Joel Borges, Jens Haueisen, and Filipe Vaz. "Dry Electrodes for Surface Electromyography Based on Architectured Titanium Thin Films." Materials 13, no. 9 (May 5, 2020): 2135. http://dx.doi.org/10.3390/ma13092135.
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Electrodes of silver/silver chloride (Ag/AgCl) are dominant in clinical settings for surface electromyography (sEMG) recordings. These electrodes need a conductive electrolyte gel to ensure proper performance, which dries during long-term measurements inhibiting the immediate electrode’s reuse and is often linked to skin irritation episodes. To overcome these drawbacks, a new type of dry electrodes based on architectured titanium (Ti) thin films were proposed in this work. The architectured microstructures were zigzags, obtained with different sputtering incidence angles (α), which have been shown to directly influence the films’ porosity and electrical conductivity. The electrodes were prepared using thermoplastic polyurethane (TPU) and stainless-steel (SS) substrates, and their performance was tested in male volunteers (athletes) by recording electromyography (EMG) signals, preceded by electrode-skin impedance measurements. In general, the results showed that both SS and TPU dry electrodes can be used for sEMG recordings. While SS electrodes almost match the signal quality parameters of reference electrodes of Ag/AgCl, the performance of electrodes based on TPU functionalized with a Ti thin film still requires further improvements. Noteworthy was the clear increase of the signal to noise ratios when the thin films’ microstructure evolved from normal growth towards zigzag microstructures, meaning that further tailoring of the thin film microstructure is a possible route to achieve optimized performances. Finally, the developed dry electrodes are reusable and allow for multiple EMG recordings without being replaced.
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Zheng, H. Z., Y. J. Zhu, Z. J. Zhang, X. R. Lin, Z. J. Zhou, X. C. Ye, and S. G. Wu. "The Effect of Electrodes’ Making Methods on the Electrochemical Performance of Nano-Ni(OH)2." Applied Mechanics and Materials 79 (July 2011): 123–27. http://dx.doi.org/10.4028/www.scientific.net/amm.79.123.
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Nano-Ni(OH)2 doped with special elements were prepared by supersonic co-precipitation method. Complex electrodes were prepared by immersion method and handwork method by mixing 8wt.% nickel hydroxides with commercial micro-size spherical nickel as the positive material of Ni-MH battery. The electrochemical performance and cyclic character affected by different electrodes’ making methods were characterized in this article. The result indicates that the discharge capacities of IM electrodes (IM electrodes mean electrodes made by handwork method) are higher than that of HM electrodes (HM electrodes mean electrodes made by handwork method). Furthermore, IM electrodes have better reversibility and higher charge efficiency than HM electrode, and lower charge potential and higher discharge plateau were also observed for IM electrodes. It's worth noting that the phenomenon is more obvious at high charge/discharge rate. When the discharge rate is 0.5C，the discharge capacity of IM electrode is higher 67.1 mAh•g -1 than that of HM electrode.
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Bickel, Karen, Thorsten Lewalter, Johannes Fischer, Christine Baumgartner, Petra Hoppmann, Klaus Tiemann, and Clemens Jilek. "Value of Mini Electrodes for Mapping Myocardial Arrhythmogenic Substrate—The Influence of Tip-to-Tissue Angulation and Irrigation Flow on Signal Quality." Journal of Vascular Diseases 1, no. 1 (August 3, 2022): 3–12. http://dx.doi.org/10.3390/jvd1010002.
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Background: The use of mini electrodes with a small surface and narrow electrode-to-electrode spacing is believed to lead to a higher electrical resolution. Until now, the effects of tip-to-tissue contact, angulation, and irrigation on signal quality and morphology are unknown. Methods: The beating heart of an open-chest pig was examined while controlling the angulation and contact between the catheter tip and myocardial tissue, as well as the irrigation of the catheter tip. The mini electrodes were mounted onto commercially available 8 mm non-irrigated and 4 mm irrigated tip catheters. Different electrode interconnections, angulations, contact forces, and irrigation flow were analyzed and compared to signals recorded from conventional electrodes. Results: A total of 63 electrode samples of 21 defined, stable settings, each lasting 30 s, were analyzed. (1) Tissue contact of mini electrodes was given as soon as the conventional tip electrode showed tissue contact. (2) Angulation of the tip-to-tissue contact showed a trend towards changes in the integral of signals derived from mini electrodes, and no significant changes were seen in signals derived from conventional or mini electrodes. (3) Irrigation flow surrounding the mini electrodes did not influence signals derived from mini electrodes, whereas conventional electrodes showed signals with a longer duration under higher irrigation. Conclusion: Mini electrodes are robust to contact force and irrigation flow regarding signal quality, whereas signals of conventional electrodes are affected by irrigation flow, leading to substantial changes in signal duration and kurtosis. Signals of mini electrodes are sensitive to local electrical changes because of a high local resolution.
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Boz, Emre Burak, Kitty Nijmeijer, and Antoni Forner-Cuenca. "Electrografting As a Versatile Approach to Engineer Porous Electrode Interfaces for Redox Flow Batteries." ECS Meeting Abstracts MA2022-01, no. 48 (July 7, 2022): 2017. http://dx.doi.org/10.1149/ma2022-01482017mtgabs.
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The intermittent nature of renewable sources can be alleviated by grid-scale energy storage technologies, such as redox flow batteries (RFBs). However, these systems are currently not cost-competitive for widespread deployment. The system costs are linked to stack performance that is limited by kinetic, ohmic and mass-transfer overpotentials as well as materials stability. Carbon fiber-based porous electrodes, ubiquitous in electrochemical reactors, strongly influence these limiting phenomena as they facilitate redox reactions on their surface, conduct electrons, and provide flow paths for reactant transport. Unfortunately, the inherently hydrophobic and inert carbon surface is not optimal for aqueous electrolytes with kinetically sluggish redox couples such as vanadium and iron1. In these systems, controlling the surface chemical state of the electrode is vital to attain significant performance gains. Popular strategies to modify surface chemistry are thermal and acid treatments with a general aim to increase the heteroatom content and number of functional groups of the carbon surface2. These functional groups increase the surface energy of inherently hydrophobic carbon electrode and can serve as active sites for redox-reactions3. However, these treatment strategies can cause embrittlement of the electrode4, mass-loss5, and the formed functional groups, especially in the case of oxygen, can manifest in multiple chemical forms, hindering proper structure-property relationships to be established. Thus, to correlate the surface chemical state to the battery performance, there is a need to develop methodologies to synthesize homogenous, conformal, and stable interfaces onto three-dimensional porous electrodes6. Here we propose electrografting as a surface modification strategy for carbon fiber-based RFB electrodes with a model molecule, taurine. Electrografting is the electrochemical analogue of chemical grafting where covalent bonds are formed between species and the conductive substrate7, with an added advantage that the charge transfer reactions responsible for bond formation can be controlled with applied voltage. We selected taurine as a model molecule to graft on carbon cloth electrodes as its amine group can undergo oxidative electrografting and we hypothesize its sulfonic acid group to be beneficial for electrode wetting, allowing coverage of the electrode surface with a thin layer of desired functional groups. We performed diagnostic studies on glassy carbon electrodes by hydrodynamic voltammetry, where the kinetic rate for the reduction of Fe3+ on taurine treated electrodes is revealed to be an order of magnitude faster than untreated electrodes (1.23 x 10-4 vs 1.84 x 10-5 cm s-1). In-situ flow cell studies in single cell configuration revealed improved performance for mixed Fe2+/3+ electrolyte, especially at lower flow rates (Figure 1). Also, for the first time, we visualized wetting dynamics of porous RFB electrodes in flow cells using neutron radiography. We find that treated electrodes imbibe the acidic electrolyte instantaneously even at low flow rates, which indicates the electrode interfaces feature hydrophilic character. Finally, we performed extended in-situ stability tests under mixed Fe2+/3+ electrolyte flow at open-circuit and applied voltage conditions. Impedance spectroscopy revealed performance degradation with pristine electrodes but not with taurine treated electrodes, confirming the formation of a stable interface with electrografting of taurine. In summary, we show that electrografting of taurine is a facile and environmentally benign approach to functionalize porous electrodes for aqueous redox flow batteries. Beyond this specific application, the possibility to extend the molecular library makes electrografting a suitable approach to engineer interfaces for next-generation electrochemical devices. References P. Chen and R. L. McCreery, Anal. Chem., 68, 3958–3965 (1996). K. Jae Kim et al., Journal of Materials Chemistry A, 3, 16913–16933 (2015). R. H. Bradley and P. Pendleton, Adsorption Science & Technology, 31, 113–133 (2013). L. Yue, W. Li, F. Sun, L. Zhao, and L. Xing, Carbon, 48, 3079–3090 (2010). K. V. Greco, A. Forner-Cuenca, A. Mularczyk, J. Eller, and F. R. Brushett, ACS Appl. Mater. Interfaces, 10, 44430–44442 (2018). A. Forner-Cuenca and F. R. Brushett, Current Opinion in Electrochemistry, 18, 113–122 (2019). D. Bélanger and J. Pinson, Chem. Soc. Rev., 40, 3995–4048 (2011). Figure 1
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Li, Chunlin, Ke Xu, and Yuanfen Chen. "Study on the Anti-Interference Performance of Substrate-Free PEDOT:PSS ECG Electrodes." Applied Sciences 14, no. 14 (July 22, 2024): 6367. http://dx.doi.org/10.3390/app14146367.
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Substrate-free electrodes are promising dry electrodes for long-term physiological electrical signal monitoring due to their ultra-thinness, conformal contact, and stable skin–electrode impedance. However, the response of substrate-free electrodes to various disturbances during electrocardiogram (ECG) monitoring and the corresponding optimization needs to be investigated. This paper investigates the specific effects of various influencing factors on skin–electrode impedance and ECG during electrocardiogram (ECG) detection. The research utilizes substrate-free poly(3,4-ethylenedioxythiophene)/poly(styrene-sulfonate) (PEDOT:PSS) electrodes. The investigation employs several methods, including skin–electrode impedance comparison, ECG waveform analysis, spectrum analysis, and signal-to-noise ratio (SNR) evaluation. To avoid the impact of physiological state differences in subjects at different times, relevant data were only compared with the same group of experiments conducted in the same period. The results demonstrate that the substrate-free conformal contact PEDOT:PSS electrode has more stable skin–electrode impedance and could obtain a more stable ECG than partial contact electrodes (the SNR of the partial contact and conformal contact electrodes are 1.2768 ± 4.0299 dB and 7.2637 ± 1.4897 dB, respectively). Furthermore, the ECG signal quality of the substrate-free conformal contact PEDOT:PSS electrode was independent of the electrode area and shape (the SNRs of the large, medium, and small electrodes are 4.0447 ± 0.4616 dB, 3.9115 ± 0.5885 dB, and 4.1556 ± 0.5557 dB, respectively; the SNRs of the circular, square, and triangular electrodes are 9.2649 ± 0.6326 dB, 9.2471 ± 0.6806 dB, and 9.1514 ± 0.6875 dB, respectively), showing high signal acquisition capability that is the same as microneedle electrodes and better than fabric electrodes. The results of clothing friction effects show that skin–electrode impedance stability was important for ECG stability, while the impedance value was not (the SNRs of friction and non-friction electrodes are 2.4128 ± 7.0784 dB and 9.2164 ± 0.6696 dB, respectively). Moreover, the skin–electrode impedance maintains stability even at a high breathing frequency, but the ECG signal fluctuates at a high breathing frequency. This experiment demonstrates that even when the skin–electrode impedance remains stable, the ECG signal can still be susceptible to interference from other factors. This study suggests that substrate-free PEDOT:PSS that could form conformal contact with the skin has higher skin–electrode impedance stability and could measure a high ECG signal even with a small electrode area, demonstrating its potential as dry ECG electrodes, but the interference from other physiological electrical signals may require better circuit design.
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Son, Seong Ho, Do Won Chung, and Won Sik Lee. "Development of Noble Metal Oxide Electrode for Low Oxygen Evolution." Advanced Materials Research 47-50 (June 2008): 750–53. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.750.
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In the electroplating and water treatment fields, as the demand and expectation on an electrode with high productivity and high efficiency are getting increased, various electrodes(DSE) with higher reactivity and durability are being developed. This study is intended to analyze the characteristics of the produced electrodes and to establish the optimum manufacturing conditions for electrode being used that we mentioned. For improving the durability, the changes of reactivity and corrosion resistance are observed as adding Tantalum and/or another components (hereafter stated as “α”) and surface treatment of substrate(Ti). As a result, increasing the amount of Iridium, the reactivity of electrode increased, and increasing amount of Tantalum, the durability of electrode increased. And thus, it is found out that Iridium and Tantalum have the opposite role each on the electrode’s reactivity and durability. And adding α and surface treatment substrate, an electrode with excellent reactivity and durability and low oxygen evolution can be manufactured. In the water treatment field like sterilizing in a swimming pool and power-plant cooling water, the high efficiency of sodium-hypochlorite generation is surely guaranteed.
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Mahdavi, Behzad, Przemyslaw Los, Marie Josée Lessard, and Jean Lessard. "A comparison of nickel boride and Raney nickel electrode activity in the electrocatalytic Hydrogenation of Phenanthrene." Canadian Journal of Chemistry 72, no. 11 (November 1, 1994): 2268–77. http://dx.doi.org/10.1139/v94-289.
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The electrocatalytic activity of nickel boride in the electrocatalytic hydrogenation (ECH) of phenanthrene in ethylene glycol–water at 80 °C has been compared to that of Raney nickel and fractal nickel. The intrinsic activity of the electrode material (real electrode activity) is the same for nickel boride and Raney nickel electrodes and is lower for fractal nickel electrodes. The apparent electrode activity of nickel boride pressed powder electrodes (Ni2B electrodes) is less than that of codeposited Raney nickel (RaNi) electrodes and pressed powder fractal nickel/Raney nickel (Ni/RaNi = 50/50 to 0/100) electrodes. The apparent activity of Ni2B electrodes is improved by adding sodium chloride to the powder and dissolving it after pressing (Ni2B–NaCl electrodes). The Ni2B–NaCl electrodes have the same apparent activity as codeposited RaNi and pressed powder Ni/RaNi (20/80 to 0/100) electrodes. The apparent and real electrode activity of Ni/RaNi electrodes increases with the RaNi content up to a 20/80 ratio. The Tafel and alternating current (ac) impedance parameters were determined for the hydrogen evolution reaction (HER) in 1 M aqueous sodium hydroxide at 25 °C at nickel boride and at codeposited RaNi electrodes. The intrinsic electrocatalytic activity for HER, expressed by the ratio of the exchange current density over the roughness factor (I0/R), is similar for Ni2B, Ni2–NaCl, and codeposited RaNi electrodes. Surface characterization of Ni2B and Ni2B–NaCl electrodes was carried out by BET, ac impedance, scanning electron microscopy, and mercury porosimetry. No direct relation between the apparent electrode activity in ECH and the surface measured by BET and ac impedance was found. The ac impedance measurements were also carried out in the presence of sodium trans-cinnamate.
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Górecka, Joanna, and Przemysław Makiewicz. "The Dependence of Electrode Impedance on the Number of Performed EEG Examinations." Sensors 19, no. 11 (June 8, 2019): 2608. http://dx.doi.org/10.3390/s19112608.
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In clinical practice, it is recommended to employ reusable electrodes for the registration of brain waves. Before registering EEG signals, the EEG technician checks the condition of all the electrodes, i.e., the occurrence of mechanical damage and the color of the electrode coating. It should be noticed that there is still no information on the permissible number of EEG examinations performed with one set of electrodes. After placement of the electrodes on the patient’s head, the scalp–electrode impedance is measured with the use of EEG equipment. When the scalp–electrode impedance achieves a value above 5 kΩ, it is necessary to replace the given electrode or to re-execute skin abrasion. The Electrochemical Impedance Spectroscopy (EIS) method was used in order to estimate the permissible number of EEG examinations performed with one set of electrodes. Ten new reusable electrodes were tested. Then, the tests were repeated after subsequent uses of those electrodes. The conducted tests led us to the conclusion that the permissible number of examinations performed with one set of electrodes is up to twenty except for the gold electrodes for which it is up to ten. Furthermore, the use of the EIS method revealed variability of impedance in the case of new electrodes.
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Cheng, Ao, Yan Shen, Tao Cui, Zhe Liu, Yu Lin, Runze Zhan, Shuai Tang, Yu Zhang, Huanjun Chen, and Shaozhi Deng. "One-Step Synthesis of Heterostructured Mo@MoO2 Nanosheets for High-Performance Supercapacitors with Long Cycling Life and High Rate Capability." Nanomaterials 14, no. 17 (August 28, 2024): 1404. http://dx.doi.org/10.3390/nano14171404.
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Supercapacitors have gained increased attention in recent years due to their significant role in energy storage devices; their impact largely depends on the electrode material. The diversity of energy storage mechanisms means that various electrode materials can provide unique benefits for specific applications, highlighting the growing trend towards nanocomposite electrodes. Typically, these nanocomposite electrodes combine pseudocapacitive materials with carbon-based materials to form heterogeneous structural composites, often requiring complex multi-step preparation processes. This study introduces a straightforward approach to fabricate a non-carbon-based Mo@MoO2 nanosheet composite electrode using a one-step thermal evaporating vapor deposition (TEVD) method. This novel electrode features Mo at the core and MoO2 as the shell and demonstrates exceptional electrochemical performance. Specifically, at a current density of 1 A g−1, it achieves a storage capacity of 205.1 F g−1, maintaining virtually unchanged capacity after 10,000 charge–discharge cycles at 2 A g−1. The outstanding long-cycle stability is ascribed to the vertical two-dimensional geometry, the superior conductivity, and pseudocapacitance of the Mo@MoO2 core-shell nanosheets. These attributes significantly improve the electrode’s charge storage capacity, charge transfer speed, and structural integrity during the cycling process. The development of the one-step grown Mo@MoO2 nanosheets offers a promising way for the advancement of high-performance, non-carbon-based supercapacitor nanocomposite electrodes.
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Imamura, Fumiya, Natsuki Nozaki, Soichiro Tottori, Shin-ichiro Osawa, Yuki Anzai, Gaobo Wang, Atsuhiro Nakagawa, and Matsuhiko Nishizawa. "Water-Triggered Self-Wrapping Cuff Electrodes for Nerve Stimulation, Oral Presentation." ECS Meeting Abstracts MA2024-02, no. 54 (November 22, 2024): 3688. https://doi.org/10.1149/ma2024-02543688mtgabs.
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In recent years, there has been an increasing interest in implantable stimulation electrodes for supporting and restoring neural functions, with ongoing development efforts aimed at their application in various areas such as vagus nerve stimulation (VNS), spinal cord stimulation (SCS), and gastric electrical stimulation (GES). The development of flexible and thin electrodes is crucial due to the delicate and uneven surfaces of tissues within the body. This is particularly important for thin nerves, which require full coverage and secure adhesion. However, soft and thin electrodes are difficult to handle in the limited space inside the body during the operation. Currently, such electrodes can only be manually attached by skilled surgeons, and the process tends to be time-consuming. Here, we develop multi-layered flexible electrodes that self-wrap around the nerves by exploiting the difference in the compression-expansion rate of each layer upon wetting. The electrodes are based on a polyvinyl alcohol (PVA) hydrogel substrate with flexible carbon fibers sandwiched between them. The self-wrapping mechanism of the electrode is designed using two layers of hydrogel substrates with different compression-expansion rates upon wetting (Fig.1b). When a stretched hydrogel is adhered to an unstretched one, they deform due to the difference in stress. Additionally, the elasticity of the hydrogel decreases when it dries but is restored upon swelling. Drying the stretched hydrogel preserves the temporarily applied elasticity, enabling the hydrogel-based electrode to become round when it swells. The stretched hydrogel was created by mixing PVA with dimethyl sulfoxide (DMSO) and water to form a gel precursor solution, which was then gelatinized using the freeze-thaw method. This gel was soaked in the solution to replace the solvent within the gel. Afterward, the gel was stretched and dried. The unstressed PVA hydrogel was prepared by dissolving PVA in water, spin-coating the solution onto glass, and gelatinizing it using the cast-dry method. Carbon fibers were placed between the two sheets of dried hydrogel and laminated with a PVA and water solution. The electrodes are flat when dry, making it easy to place under the nerve. Additionally, it automatically deforms when water is applied, making installation easier than traditional electrodes (Figure 1c). It takes only about 30 seconds to completely encase the nerve. This functionality is expected to reduce the time required for surgery compared to traditional electrodes. The deformed hydrogel electrode is securely fixed due to the hydrogel's elasticity and does not move in a direction parallel to the nerve or dislocate vertically. Animal experiments were conducted by electrically stimulating the vagus nerve of pigs. During electrical stimulation, a bradycardia, which is a side effect of vagus nerve stimulation, was observed. This demonstrates the electrode's capability for stimulation. In conclusions, we developed the flexible electrodes that self-wraps around the nerves by exploiting the difference of the internal compression-expansion rate upon wetting. We confirmed that the wrapping force was large enough to stably fix the electrodes on the nerves while being small enough not to damage them. Finally, we tested the developed electrodes to stimulate the vagus nerve of pig and confirmed the effectiveness of the electrical stimulation. We hope that this electrode will be a significant step towards the practical use of hydrogel electrodes for stable fixation to the nerves and simplifying surgical procedures. In the future, we aim to further develop this technology and develop more advanced electrode designs that can be applied to various nerve stimulation treatments. Reference: Terutsuki. D, Yoroizuka. H, Osawa. S, Ogihara. Y, Abe. H, Nakagawa. A, Iwasaki. M, Nishizawa. M, “Totally Organic Hydrogel-Based Self-Closing Cuff Electrode for Vagus Nerve Stimulation.” Adv. Healthcare Mater. 2022, 11, 2201627. Fig.1 (a) Illustration of self-wrapping electrode. (b) Schematic diagram of electrode fabrication and self-wrapping mechanism. Light blue is freeze-thawed PVA hydrogel with DMSO pre-stretched before drying. Dark blue is cast-dried PVA hydrogel. (c) Image of wrapping an electrode around a nerve. The fabricated hydrogel electrode completely covers the nerve in about 30 seconds after water is applied. Figure 1
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Vadera, Sumeet, Amar R. Marathe, Jorge Gonzalez-Martinez, and Dawn M. Taylor. "Stereoelectroencephalography for continuous two-dimensional cursor control in a brain-machine interface." Neurosurgical Focus 34, no. 6 (June 2013): E3. http://dx.doi.org/10.3171/2013.3.focus1373.
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Stereoelectroencephalography (SEEG) is becoming more prevalent as a planning tool for surgical treatment of intractable epilepsy. Stereoelectroencephalography uses long, thin, cylindrical “depth” electrodes containing multiple recording contacts along each electrode's length. Each lead is inserted into the brain percutaneously. The advantage of SEEG is that the electrodes can easily target deeper brain structures that are inaccessible with subdural grid electrodes, and SEEG does not require a craniotomy. Brain-machine interface (BMI) research is also becoming more common in the Epilepsy Monitoring Unit. A brain-machine interface decodes a person's desired movement or action from the recorded brain activity and then uses the decoded brain activity to control an assistive device in real time. Although BMIs are primarily being developed for use by severely paralyzed individuals, epilepsy patients undergoing invasive brain monitoring provide an opportunity to test the effectiveness of different invasive recording electrodes for use in BMI systems. This study investigated the ability to use SEEG electrodes for control of 2D cursor velocity in a BMI. Two patients who were undergoing SEEG for intractable epilepsy participated in this study. Participants were instructed to wiggle or rest the hand contralateral to their SEEG electrodes to control the horizontal velocity of a cursor on a screen. Simultaneously they were instructed to wiggle or rest their feet to control the vertical component of cursor velocity. The BMI system was designed to detect power spectral changes associated with hand and foot activity and translate those spectral changes into horizontal and vertical cursor movements in real time. During testing, participants used their decoded SEEG signals to move the brain-controlled cursor to radial targets that appeared on the screen. Although power spectral information from 28 to 32 electrode contacts were used for cursor control during the experiment, post hoc analysis indicated that better control may have been possible using only a single SEEG depth electrode containing multiple recording contacts in both hand and foot cortical areas. These results suggest that the advantages of using SEEG for epilepsy monitoring may also apply to using SEEG electrodes in BMI systems. Specifically, SEEG electrodes can target deeper brain structures, such as foot motor cortex, and both hand and foot areas can be targeted with a single SEEG electrode implanted percutaneously. Therefore, SEEG electrodes may be an attractive option for simple BMI systems that use power spectral modulation in hand and foot cortex for independent control of 2 degrees of freedom.
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Katayama, Misaki, and Kazuo Kato. "Simultaneous Analysis of Reaction Distribution at LiFePO4 and LiCoO2 Electrodes of Lithium-Ion Batteries." ECS Meeting Abstracts MA2024-02, no. 4 (November 22, 2024): 454. https://doi.org/10.1149/ma2024-024454mtgabs.
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The electrode reaction distribution of lithium-ion batteries is a noteworthy issue for the construction of safe and sustainable storage battery systems. Electrode reactions at composite electrodes are inhomogeneous on the micrometer to millimeter scale due to local differences in electronic and ionic conductivity. There are many reports on the reaction distribution of single electrodes. How the inhomogeneous chemical state distribution generated in the electrode affects the subsequent charge-discharge reaction has not been systematically studied. The purpose of this study is to clarify how the inhomogeneous reaction distribution affects the other electrode. Synchrotron radiation X-rays can be used to observe inhomogeneous states without disassembling the battery. However, because common negative electrode materials are composed of light elements, X-ray absorption fine structure (XAFS) is usually not applicable for in situ observation of the negative electrode of practical batteries. Therefore, in this study, we fabricated a battery by combining a LiFePO4 electrode and a LiCoO2 electrode, which are normally used as positive electrodes, and analyzed the heterogeneous electrode reactions inside the battery for both electrodes simultaneously. Although the battery is not a combination of positive and negative electrodes as used in practice, the distribution of the chemical states of both electrodes can be visualized using X-rays. XAFS experiments using a two-dimensional detector were performed at SPring-8 BL01B1. The chemical state of the LiFePO4 electrode was determined from the Fe K-edge XAFS spectrum, and that of the LiCoO2 electrode was determined from the Co K-edge to create a chemical state map in the electrode. The battery was equipped with a graphite electrode in addition to LiFePO4 and LiCoO2 electrodes for the initial delithiation process. Charging and discharging were repeated with a combination of LiFePO4 and LiCoO2 electrodes to examine the behavior of the reaction distribution and the positional relationship between the reaction distributions of both electrodes. The result that the reaction progressed in the region of the LiCoO2 electrode that overlapped the region where the reaction was progressing at the LiFePO4 electrode clearly indicates that the inhomogeneous reaction at the electrode propagated to the opposite electrode.
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Wójcik, Szymon, and Małgorzata Jakubowska. "Optimization of anethole determination using differential pulse voltammetry on glassy carbon electrode, boron doped diamond electrode and carbon paste electrode." Science, Technology and Innovation 3, no. 2 (December 27, 2018): 21–26. http://dx.doi.org/10.5604/01.3001.0012.8152.
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Voltammetry is the general term for all techniques in which the current is measured as a function of electrode potential. The voltammetric techniques can be applied for the quantitative analysis of inorganic and organic species and are best suited for substances which can be either oxidized or reduced on electrodes. These techniques are characterized by high sensitivity which results in the possibility of performing determinations at a low concentration level. In voltammetry, many different types of working electrodes are applied. One of the important groups are solid electrodes, among which carbon electrodes play an important role. They represent a good alternative to mercury electrodes, however, surface preparation before the usage is required. In this work anethole determination will be presented using three types of carbon electrodes: glassy carbon electrode, boron doped diamond electrode and carbon paste electrode. Optimization process will be also described.
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Xu, Ran, Johannes Achberger, Dario von Wedel, Peter Vajkoczy, Julia Onken, and Ulf C. Schneider. "Utilization of Epidural Electrodes as a Diagnostic Tool in Intractable Epilepsy—A Technical Note." Micromachines 13, no. 3 (February 28, 2022): 397. http://dx.doi.org/10.3390/mi13030397.
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The utilization of epidural electrodes in the preoperative evaluation of intractable epilepsy is a valuable but underrepresented tool. In recent years, we have adapted the use of cylindrical epidural 1-contact electrodes (1-CE) instead of Peg electrodes. 1-CEs are more versatile since their explantation is a possible bedside procedure. Here we report our experience with 1-CEs as well as associated technical nuances. This retrospective analysis included 56 patients with intractable epilepsy who underwent epidural electrode placement for presurgical evaluation at the Department of Neurosurgery at the Charité University Hospital from September 2011 to July 2021. The median age at surgery was 36.3 years (range: 18–87), with 30 (53.6%) female and 26 (46.4%) male patients. Overall, 507 electrodes were implanted: 93 Fo electrodes, 33 depth electrodes, and 381 epidural electrodes, with a mean total surgical time of 100.5 ± 38 min and 11.8 ± 5 min per electrode. There was a total number of 24 complications in 21 patients (8 Fo electrode dislocations, 6 CSF leaks, 6 epidural electrode dislocations or malfunction, 3 wound infections, and 2 hemorrhages); 11 of these required revision surgery. The relative electrode complication rates were 3/222 (1.4%) in Peg electrodes and 3/159 (1.9%) in 1-CE. In summary, epidural recording via 1-CE is technically feasible, harbours an acceptable complication rate, and adequately replaces Peg electrodes.
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Song, Jinzhong, Tianshu Zhou, Zhonggang Liang, Ruoxi Liu, Jianping Guo, Xinming Yu, Zhongping Cao, Chuang Yu, Qingjun Liu, and Jingsong Li. "Electrochemical Characteristics Based on Skin-Electrode Contact Pressure for Dry Biomedical Electrodes and the Application to Wearable ECG Signal Acquisition." Journal of Sensors 2021 (September 15, 2021): 1–9. http://dx.doi.org/10.1155/2021/7741881.
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Based on one simulated skin-electrode electrochemical interface, some electrochemical characteristics based on skin-electrode contact pressure (SECP) for dry biomedical electrodes were analysed and applied in this research. First, 14 electrochemical characteristics including 2 static impedance (SI) characteristics, 11 alternating current impedance (ACI) characteristics and one polarization voltage (PV), and 4 SECP characteristics were extracted in one electrochemical evaluation platform, and their correlation trends were statistically analysed. Second, dry biomedical electrode samples developed by the company and the laboratory, including textile electrodes, Apple watch, AMAZFIT rice health bracelet 1S, and stainless steel electrodes, were placed horizontally and vertically on the “skin” surface of the electrochemical evaluation platform, whose polarization voltages were quantitatively analysed. Third, electrocardiogram (ECG) collection circuits based on an impedance transformation (IT) circuit for textile electrodes were designed, and a wearable ECG acquisition device was designed, which could obtain complete ECG signals. Experimental results showed SECP characteristics for dry electrodes had good correlations with static impedance and ACI characteristics and the better correlation values among 2-10 Hz. In addition, polarization voltages in vertical state were smaller in horizontal state for dry biomedical electrodes, and polarization voltage of electrode pair (PVEP) values for Apple watch bottom was always smaller than ones for Apple watch crown and LMF-2 textile electrode. And the skin-electrode contact impedance of IT textile electrodes was less than the traditional textile electrodes.
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Zhang, Wenguang, Xuele Yin, and Xuhui Zhou. "Optimal design and evaluation of a multi-shank structure based neural probe." International Journal of Applied Electromagnetics and Mechanics 64, no. 1-4 (December 10, 2020): 1373–80. http://dx.doi.org/10.3233/jae-209456.
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In order to develop long-lifetime neural electrodes, the insertion tissue injury caused by two optimized neural electrode (convex streamline electrode and vibration attenuation electrode) models were evaluated compared with a reference electrode. Based on the experimental evaluation system for testing tissue injury, the effects of insertion speeds on tissue injury of the two optimized electrodes with different insertion depths were studied. The maximum tissue strain caused by the two optimized neural electrodes firstly increased and then decreased with the increase of insertion speed at the depths of 3 mm and 4.5 mm. The insertion forces caused by vibration attenuation electrode are steady with the change of insertion speed. The convex streamline neural electrode caused less tissue injury compared with the other two electrodes. The higher or lower insertion speed causes smaller tissue strain for the two optimized electrodes, which is conductive to set implantation parameters to minimize tissue injury.
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Zhang, Wenguang, Xuele Yin, Jie Xie, Yakun Ma, and Zhengwei Li. "Experimental evaluation of optimal-designed neural electrodes based on simulated implantation system." International Journal of Applied Electromagnetics and Mechanics 64, no. 1-4 (December 10, 2020): 1401–9. http://dx.doi.org/10.3233/jae-209459.
Full textAbstract:
In order to develop long-lifetime neural electrodes, the insertion tissue injury caused by two optimized neural electrode (convex streamline electrode and vibration attenuation electrode) models were evaluated compared with a reference electrode. Based on the experimental evaluation system for testing tissue injury, the effects of insertion speeds on tissue injury of the two optimized electrodes with different insertion depths were studied. The maximum tissue strain caused by the two optimized neural electrodes firstly increased and then decreased with the increase of insertion speed at the depths of 3 mm and 4.5 mm. The insertion forces caused by vibration attenuation electrode are steady with the change of insertion speed. The convex streamline neural electrode caused less tissue injury compared with the other two electrodes. The higher or lower insertion speed causes smaller tissue strain for the two optimized electrodes, which is conductive to set implantation parameters to minimize tissue injury.
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Haueisen, Jens, Patrique Fiedler, Anna Bernhardt, Ricardo Gonçalves, and Carlos Fonseca. "Novel dry electrode EEG headbands for home use: Comparing performance and comfort." Current Directions in Biomedical Engineering 6, no. 3 (September 1, 2020): 139–42. http://dx.doi.org/10.1515/cdbme-2020-3036.
Full textAbstract:
AbstractMonitoring brain activity at home using electroencephalography (EEG) is an increasing trend for both medical and non-medical applications. Gel-based electrodes are not suitable due to the gel application requiring extensive preparation and cleaning support for the patient or user. Dry electrodes can be applied without prior preparation by the patient or user. We investigate and compare two dry electrode headbands for EEG acquisition: a novel hybrid dual-textile headband comprising multipin and multiwave electrodes and a neoprene-based headband comprising hydrogel and spidershaped electrodes. We compare the headbands and electrodes in terms of electrode-skin impedance, comfort, electrode offset potential and EEG signal quality. We did not observe considerable differences in the power spectral density of EEG recordings. However, the hydrogel electrodes showed considerably increased impedances and offset potentials, limiting their compatibility with many EEG amplifiers. The hydrogel and spider-shaped electrodes required increased adduction, resulting in a lower wearing comfort throughout the application time compared to the novel headband comprising multipin and multiwave electrodes.
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Zhen, Shao Hua, Li Bao An, and Chun Rui Chang. "Simulation on the Dielectrophoretic Assembly of Carbon Nanotubes." Advanced Materials Research 750-752 (August 2013): 328–31. http://dx.doi.org/10.4028/www.scientific.net/amr.750-752.328.
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Dielectrophoresis (DEP) has been verified to be an efficient means of assembling carbon nanotubes (CNTs) for various applications. This paper simulates the electric field distribution of the quadruple electrode structure when the external AC voltage is applied between a pair of opposite electrodes. There exist induced electric potentials between high voltage electrodes and floating electrodes and thus floating electrodes seriously change the field distribution. For a pair of wide parallel electrodes, the deposition of one CNT bridging the electrode pair will greatly alter the local electric field and repel the further deposition of CNTs in the vicinity. The screening distance is relevant with the width of the electrode gap, which provides a way to estimate the density of assembled CNTs between the electrode pair.
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Reza, Mohammad Shamim, Lu Jin, You Jeong Jeong, Tong In Oh, Hongdoo Kim, and Kap Jin Kim. "Electrospun Rubber Nanofiber Web-Based Dry Electrodes for Biopotential Monitoring." Sensors 23, no. 17 (August 24, 2023): 7377. http://dx.doi.org/10.3390/s23177377.
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This study aims to find base materials for dry electrode fabrication with high accuracy and without reducing electrode performance for long-term bioelectric potential monitoring after electroless silver plating. Most applications of dry electrodes that have been developed in the past few decades are restricted by low accuracy compared to commercial Ag/AgCl gel electrodes, as in our previous study of PVDF-based dry electrodes. In a recent study, however, nanoweb-based chlorinated polyisoprene (CPI) and poly(styrene-b-butadiene-b-styrene) (SBS) rubber were selected as promising candidates due to their excellent elastic properties, as well as their nanofibril nature, which may improve electrode durability and skin contact. The electroless silver plating technique was employed to coat the nanofiber web with silver, and silver nanoweb(AgNW)-based dry electrodes were fabricated. The key electrode properties (contact impedance, step response, and noise characteristics) for AgNW dry electrodes were investigated thoroughly using agar phantoms. The dry electrodes were subsequently tested on human subjects to establish their realistic performance in terms of ECG, EMG monitoring, and electrical impedance tomography (EIT) measurements. The experimental results demonstrated that the AgNW dry electrodes, particularly the SBS-AgNW dry electrodes, performed similarly to commercial Ag/AgCl gel electrodes and were outperformed in terms of long-term stability.
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Furst, Ariel L. "Low-Cost Platforms for Point-of-Use Sensors." ECS Meeting Abstracts MA2023-02, no. 52 (December 22, 2023): 2492. http://dx.doi.org/10.1149/ma2023-02522492mtgabs.
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Electrochemical biosensors are promising for sensing in low-resource settings because they are easy use and low-cost. Disposable screen-printed electrodes are popular for biosensing applications, but the dopants in the ink used for gold electrode production can interfere with electrode modification and sensing. We have developed an alternative disposable electrode made from high-quality gold leaf. We compared the topology and performance of three different disposable gold electrodes: our gold leaf electrodes and two commercial screen-printed versions. Our electrodes consistently outperformed commercial electrodes for biosensing, and we have further expanded these electrodes for the detection of infectious disease. In contrast, carbon screen-printed electrodes tend to be lower cost and higher quality than their gold counterparts. However, chemistry to modify them with biomolecules remains more challenging than self-assembly on gold. We have therefore developed new chemistries to enable the facile modification of these electrodes with biomolecules and have successfully applied these modified electrodes for environmental sensing. Together, these works demonstrate the importance of fundamental advances in platform design to enable improved technologies.
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Shi, Haozhi, Shulei Wang, Jijun Zhang, Zhubin Shi, Jiahua Min, Jian Huang, and Linjun Wang. "Investigation on the Rapid Annealing of Ti-Au Composite Electrode on n-Type (111) CdZnTe Crystals." Crystals 10, no. 3 (February 29, 2020): 156. http://dx.doi.org/10.3390/cryst10030156.
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In this paper, the ohmic properties of Ti, Al, and Ti-Au composite electrodes on n-type (111) CdZnTe crystal deposited by vacuum evaporation method were first analyzed, and then the rapid annealing of Ti-Au electrode under Ar atmosphere with different temperature and time was explored. The ohmic property and barrier height were evaluated by current–voltage (I–V) and capacitance-voltage (C–V) measurements, and the adhesion strength of various electrodess to CdZnTe was compared. The Ti-Au electrode on CdZnTe showed the lowest leakage current and barrier height, and the highest adhesion strength among the three kinds of electrodes on (111) CdZnTe crystals. The rapid annealing of Ti-Au electrode under Ar atmosphere was proved to improve its ohmic property and adhesion strength, and the optimal annealing temperature and time were found to be 423 K and 6 min, respectively. The barrier height of the Ti-Au/CdZnTe electrode is 0.801 eV through rapid annealing for 6 min at 423 K annealing temperature, and the adhesion is 1225 MPa, which increases by 50% compared with that without rapid annealing.
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Kong, Wei, Mengtong Zhang, Zhen Han, and Qiang Zhang. "A Theoretical Model for the Triple Phase Boundary of Solid Oxide Fuel Cell Electrospun Electrodes." Applied Sciences 9, no. 3 (January 31, 2019): 493. http://dx.doi.org/10.3390/app9030493.
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Electrospinning is a new state-of-the-art technology for the preparation of electrodes for solid oxide fuel cells (SOFC). Electrodes fabricated by this method have been proven to have an experimentally superior performance compared with traditional electrodes. However, the lack of a theoretic model for electrospun electrodes limits the understanding of their benefits and the optimization of their design. Based on the microstructure of electrospun electrodes and the percolation threshold, a theoretical model of electrospun electrodes is proposed in this study. Electrospun electrodes are compared to fibers with surfaces that were coated with impregnated particles. This model captures the key geometric parameters and their interrelationship, which are required to derive explicit expressions of the key electrode parameters. Furthermore, the length of the triple phase boundary (TPB) of the electrospun electrode is calculated based on this model. Finally, the effects of particle radius, fiber radius, and impregnation loading are studied. The theory model of the electrospun electrode TPB proposed in this study contributes to the optimization design of SOFC electrospun electrode.
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Kim, Hyelim, Soohyeon Rho, Sora Han, Daeyoung Lim, and Wonyoung Jeong. "Fabrication of Textile-Based Dry Electrode and Analysis of Its Surface EMG Signal for Applying Smart Wear." Polymers 14, no. 17 (September 2, 2022): 3641. http://dx.doi.org/10.3390/polym14173641.
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Ag/AgCl hydrogel electrodes, which are wet electrodes, are generally used to acquire bio-signals non-invasively. Research concerning dry electrodes is ongoing due to the following limitations of wet electrodes: (1) skin irritation and disease when attached for a long time; (2) poor adhesion due to sweat; and (3) considerable cost due to disposable use. Accordingly, electrodes in film, embroidery, and knit forms were manufactured from conductive sheets and conductive yarns, which are typical textile-type dry electrode materials, using different manufacturing methods and conditions. The prepared electrodes were conducted to measure the morphology, surface resistance, skin-electrode impedance, EMG signal acquisition, and analysis. The conductive sheet type electrode exhibited a similar skin-impedance, noise, and muscle activation signal amplitude to the Ag/AgCl gel electrode due to the excellent adhesion and shape stabilization. Embroidery electrodes were manufactured based on two-dimension lock stitch (Em_LS) and three-dimension moss-stitch (Em_MS). More stable EMG signal acquisition than Em_LS was possible when manufactured with Em_MS. The knit electrode was manufactured with the typical structures of plain, purl, and interlock. Although it was possible to acquire EMG signals, considerable noise was generated as the shape and size of the electrodes were changed due to the stretch characteristics of the knit structure. Finally, the applicability of the textile-type dry electrode was confirmed by combining it with a wearable device. More stable and accurate EMG signal acquirement will be possible through more precise parameter control in the future.
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Syed Abdullah, Syarifah, Nur Farahi Idris, Normiza Mohamad Nor, Nurul Nadia Ahmad, and Azwan Mahmud. "Effect of high resistivity soil under high impulse currents." Bulletin of Electrical Engineering and Informatics 13, no. 4 (August 1, 2024): 2269–78. http://dx.doi.org/10.11591/eei.v13i4.7287.
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In this paper, experimental test results of several ground electrodes surrounded with gravelly soil medium subjected to high impulse currents were studied, to investigate the effect of confined soil surround electrodes. Ground resistance measurements were performed at low magnitude of voltage and current, where the results are compared to the impulse characteristics of ground electrodes. This paper shows a significant difference in the RDC values and impulse characteristics of ground electrodes when gravelly soil medium surrounded the ground electrode in comparison to the electrodes installed in natural soil. This indicates that the confined soil around the electrode has a major effect on the performance of ground electrodes, whether at steady state or under high impulse conditions. Equivalent circuit for each tested electrode was developed with personal simulation program with integrated circuit emphasis (PSPICE), where the effect of inductance was seen in the electrodes surrounded with gravelly soil.
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LaViolette, Peter S., Scott D. Rand, Manoj Raghavan, Benjamin M. Ellingson, Kathleen M. Schmainda, and Wade Mueller. "Three-Dimensional Visualization of Subdural Electrodes for Presurgical Planning." Operative Neurosurgery 68, suppl_1 (March 1, 2011): ons152—ons161. http://dx.doi.org/10.1227/neu.0b013e31820783ba.
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Abstract BACKGROUND: Accurate localization and visualization of subdural electrodes implanted for intracranial electroencephalography in cases of medically refractory epilepsy remains a challenging clinical problem. OBJECTIVE: We introduce a technique for creating accurate 3-dimensional (3D) brain models with electrode overlays, ideal for resective surgical planning. METHODS: Our procedure uses postimplantation magnetic resonance imaging (MRI) and computed tomographic (CT) imaging to create 3D models of compression-affected brain combined with intensity-thresholded CT-derived electrode models using freely available software. Footprints, or “shadows,” beneath electrodes are also described for better visualization of sulcus-straddling electrodes. Electrode models were compared with intraoperative photography for validation. RESULTS: Realistic representations of intracranial electrode positions on patient-specific postimplantation MRI brain renderings were reliably created and proved accurate when compared with photographs. Electrodes placed interhemispherically were also visible with our rendering technique. Electrode shadows were useful in locating electrodes that straddle sulci. CONCLUSION: We present an accurate method for visualizing subdural electrodes on brain compression effected 3D models that serves as an ideal platform for surgical planning.