Journal articles on the topic 'Electrode interface'
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1
Polachan, Kurian, Baibhab Chatterjee, Scott Weigand, and Shreyas Sen. "Human Body–Electrode Interfaces for Wide-Frequency Sensing and Communication: A Review." Nanomaterials 11, no. 8 (August 23, 2021): 2152. http://dx.doi.org/10.3390/nano11082152.
Abstract:
Several on-body sensing and communication applications use electrodes in contact with the human body. Body–electrode interfaces in these cases act as a transducer, converting ionic current in the body to electronic current in the sensing and communication circuits and vice versa. An ideal body–electrode interface should have the characteristics of an electrical short, i.e., the transfer of ionic currents and electronic currents across the interface should happen without any hindrance. However, practical body–electrode interfaces often have definite impedances and potentials that hinder the free flow of currents, affecting the application’s performance. Minimizing the impact of body–electrode interfaces on the application’s performance requires one to understand the physics of such interfaces, how it distorts the signals passing through it, and how the interface-induced signal degradations affect the applications. Our work deals with reviewing these elements in the context of biopotential sensing and human body communication.
2
Aharon, Hannah, Omer Shavit, Matan Galanty, and Adi Salomon. "Second Harmonic Generation for Moisture Monitoring in Dimethoxyethane at a Gold-Solvent Interface Using Plasmonic Structures." Nanomaterials 9, no. 12 (December 16, 2019): 1788. http://dx.doi.org/10.3390/nano9121788.
Abstract:
Second harmonic generation (SHG) is forbidden from most bulk metals because metals are characterized by centrosymmetric symmetry. Adsorption or desorption of molecules at the metal interface can break the symmetry and lead to SHG responses. Yet, the response is relatively low, and minute changes occurring at the interface, especially at solid/liquid interfaces, like in battery electrodes are difficult to assess. Herein, we use a plasmonic structure milled in a gold electrode to increase the overall SHG signal from the interface and gain information about small changes occurring at the interface. Using a specific homebuilt cell, we monitor changes at the liquid/electrode interface. Specifically, traces of water in dimethoxyethane (DME) have been detected following changes in the SHG responses from the plasmonic structures. We propose that by plasmonic structures this technique can be used for assessing minute changes occurring at solid/liquid interfaces such as battery electrodes.
3
Keogh, Conor. "Optimizing the neuron-electrode interface for chronic bioelectronic interfacing." Neurosurgical Focus 49, no. 1 (July 2020): E7. http://dx.doi.org/10.3171/2020.4.focus20178.
Abstract:
Engineering approaches have vast potential to improve the treatment of disease. Brain-machine interfaces have become a well-established means of treating some otherwise medically refractory neurological diseases, and they have shown promise in many more areas. More widespread use of implanted stimulating and recording electrodes for long-term intervention is, however, limited by the difficulty in maintaining a stable interface between implanted electrodes and the local tissue for reliable recording and stimulation.This loss of performance at the neuron-electrode interface is due to a combination of inflammation and glial scar formation in response to the implanted material, as well as electrical factors contributing to a reduction in function over time. An increasing understanding of the factors at play at the neural interface has led to greater focus on the optimization of this neuron-electrode interface in order to maintain long-term implant viability.A wide variety of approaches to improving device interfacing have emerged, targeting the mechanical, electrical, and biological interactions between implanted electrodes and the neural tissue. These approaches are aimed at reducing the initial trauma and long-term tissue reaction through device coatings, optimization of mechanical characteristics for maximal biocompatibility, and implantation techniques. Improved electrode features, optimized stimulation parameters, and novel electrode materials further aim to stabilize the electrical interface, while the integration of biological interventions to reduce inflammation and improve tissue integration has also shown promise.Optimization of the neuron-electrode interface allows the use of long-term, high-resolution stimulation and recording, opening the door to responsive closed-loop systems with highly selective modulation. These new approaches and technologies offer a broad range of options for neural interfacing, representing the possibility of developing specific implant technologies tailor-made to a given task, allowing truly personalized, optimized implant technology for chronic neural interfacing.
4
Leskes, Michal. "(Invited) Elucidating the Structure and Function of the Electrode-Electrolyte Interface By New Solid State NMR Approaches." ECS Meeting Abstracts MA2022-01, no. 2 (July 7, 2022): 369. http://dx.doi.org/10.1149/ma2022-012369mtgabs.
Abstract:
The development of high-energy, long-lasting energy storage systems based on rechargeable batteries relies on our ability to control charge storage and degradation processes in the bulk of the electrode materials and at the electrode-electrolyte interface. NMR spectroscopy is exceptionally suited to follow the electrochemical and chemical processes in the bulk of the electrodes and electrolyte, providing atomic scale structural insight into the charge storage mechanisms and ion transport properties. However, interfacial properties, such as the processes governing charge transport between the electrode and the electrolyte, are much harder to study. These processes typically involve thin, heterogeneous and disordered layers that are formed chemically/electrochemically in the battery cell or artificially through coating the electrode material. While NMR is in principle an excellent approach for probing disordered phases, its low sensitivity presents an enormous challenge in the detection of interfacial processes. In this talk I will describe recent approaches to overcome the sensitivity limitation by the use of Dynamic Nuclear Polarization (DNP). In DNP, the large electron spin polarization is used to boost the sensitivity of NMR spectroscopy by orders of magnitude. I will show how we can use this approach to detect the solid-electrolyte interphase (SEI), electrode coatings as well as the electrode’s bulk, with unprecedented sensitivity. Furthermore, I will present new approaches to probe ion transport properties of various interfaces. These allow us to get insight into the functional role of interfaces, which along with the chemical and structural insight, can provide design rules for beneficial interfaces, an essential aspect for developing long-lasting energy storage systems.
5
Wei, Weichen, and Xuejiao Wang. "Graphene-Based Electrode Materials for Neural Activity Detection." Materials 14, no. 20 (October 18, 2021): 6170. http://dx.doi.org/10.3390/ma14206170.
Abstract:
The neural electrode technique is a powerful tool for monitoring and regulating neural activity, which has a wide range of applications in basic neuroscience and the treatment of neurological diseases. Constructing a high-performance electrode–nerve interface is required for the long-term stable detection of neural signals by electrodes. However, conventional neural electrodes are mainly fabricated from rigid materials that do not match the mechanical properties of soft neural tissues, thus limiting the high-quality recording of neuroelectric signals. Meanwhile, graphene-based nanomaterials can form stable electrode–nerve interfaces due to their high conductivity, excellent flexibility, and biocompatibility. In this literature review, we describe various graphene-based electrodes and their potential application in neural activity detection. We also discuss the biological safety of graphene neural electrodes, related challenges, and their prospects.
6
Ostrovsky, S., S. Hahnewald, R. Kiran, P. Mistrik, R. Hessler, A. Tscherter, P. Senn, et al. "Conductive hybrid carbon nanotube (CNT)–polythiophene coatings for innovative auditory neuron-multi-electrode array interfacing." RSC Advances 6, no. 48 (2016): 41714–23. http://dx.doi.org/10.1039/c5ra27642j.
7
Ly, Suw Young, Hyeon Jeong Park, Celina Jae Won Jang, Katlynn Ryu, Woo Seok Kim, Sung Joo Jang, and Kyung Lee. "Implanted Bioelectric Neuro Assay with Sensing Interface Circuit." Sensor Letters 18, no. 9 (September 1, 2020): 686–93. http://dx.doi.org/10.1166/sl.2020.4274.
Abstract:
Neuromolecular glucose and dopamine assays were searched using a DNA immobilized onto a carbon nanotube paste electrode (PE). The analytical molecular detection limits of 0.13 ugL–1(6.855 × 10–10 M) Dopamine and 1.9 ugL–1 (1.06 × 10–8 M) glucose were attained using square wave stripping voltammetry. A handmade three-electrode system was implanted in the nerve network of a fish backbone, and two working electrodes were implanted in left and right pinna muscles. These were interfaced with a neuron electrochemical workstation and a nerve machine sensing circuit. This interface could be obtained for the psychological function and other body functions. The interfaced circuit could be controlled with a machine system. The results are useful in machine brain intercontrol systems.
8
Imanishi, Akihito. "(Invited, Digital Presentation) Influence of Hemisphere-Shaped Nanodimples of Gold Electrode on Capacitance in Ionic Liquid." ECS Meeting Abstracts MA2022-01, no. 13 (July 7, 2022): 883. http://dx.doi.org/10.1149/ma2022-0113883mtgabs.
Abstract:
Ionic liquids (ILs) have attracted much attention as promising electrolytes for electrochemical devices due to their wide electrochemical window (stability) and negligible vaporization. For such applications, nanostructured electrodes have advantage on their large surface area leading to accumulation of large density energy at the interface. However, recent reports on IL/electrode interfaces revealed that quite unique structures can be formed, and it is not clear how the interface forms and how it changes by forming an electric double layer (EDL). In this study, we investigated the interfacial capacitance of nanostructured Au electrodes using electrochemical impedance spectroscopy (EIS) and IR measurements. Polystyrene beads were self-assembled in a close packed form on a gold substrate by dipping in polystyrene beads solution and rapid drying. Au electrodeposition on thus prepared surface followed by removal of the beads resulted in the fabrication of a nanostructured Au electrode with periodic dimples. Electrochemical behavior of a ferrocene dissolved ionic liquid (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide (BMI-TFSA)) at the nanostructured and flat Au electrodes were investigated by EIS. We found that the capacitance of the nanostructured electrode was smaller than that of the flat electrode in the whole potential range. This result suggests that the thickness of the electric double layer formed in the nano-sized dimple is thicker than that formed on the flat surface. In the case of nanostructured Au electrode having 160 nm diameter dimples, the large capacitance was observed comparing with other electrodes having the dimples of different sizes. In addition, on the negative-going scan, the capacitance takes maximum at 0.1 V vs. Fc/Fc+, whereas no peak was found on the reverse positive-going scan. This result indicates that the exchange of cation/anion layers smoothly proceeded on the negative-going scan, whereas such a smooth exchange was prevented due to strongly surface-adsorbed BMIM+ on the positive-going scan. We also found that the hysteresis behavior was relatively suppressed in the case of the electrodes having 70 nm and 120 nm diameter dimples. We carried out the In-situ ATR-IR measurement to investigate the structure of ionic liquid molecules at the ionic liquid/electrode interface. The details of the relationships between the arrangement of ionic liquid at the interface and the capacitance of the electrode will be discussed.
9
Misra, Veena, Gerry Lucovsky, and Gregory Parsons. "Issues in High-ĸ Gate Stack Interfaces." MRS Bulletin 27, no. 3 (March 2002): 212–16. http://dx.doi.org/10.1557/mrs2002.73.
Abstract:
AbstractWe address current challenges in the fundamental understanding of physical and chemical processes that occur in the fabrication of the transistor gate stack structure. Critical areas include (1) the interface between bulk silicon and high-dielectric-constant (high-ĸ) insulators, (2) the interface between high-ĸ insulators and advanced gate electrodes, and (3) the internal interfaces that form within dielectric stacks with nonuniform material and structure compositions. We approach this topic from a fundamental understanding of bonding and electronic structure at the interfaces, and of film-growth kinetics in comparison with thermodynamics predictions. Implications for the dielectric/electrode interface with metallic gates and issues with integration will also be presented.
10
Lenser, Christian, Alexander Schwiers, Denise Ramler, and Norbert H. Menzler. "Investigation of the Electrode-Electrolyte Interfaces in Solid Oxide Cells." ECS Meeting Abstracts MA2023-01, no. 54 (August 28, 2023): 262. http://dx.doi.org/10.1149/ma2023-0154262mtgabs.
Abstract:
The interfaces between electrodes and electrolyte are critical locations in a solid oxide cell (SOC). These interfaces originate from the chemical interaction of two different materials during processing, and are therefore very sensitive to the chemical nature of the materials, as well as the thermal history of the cell. On the air side, perovskite air electrodes tend to form insulating zirconates when sintered on stabilized zirconia, the most common electrolyte material. On the fuel side, using an ionic conductor with a different chemical composition as zirconia can lead to pronounced interdiffusion and the formation of new phases. Interlayers of doped ceria are frequently used in order to suppress these undesired chemical reactions between electrodes and stabilized zirconia electrolytes. Prior investigations have focused extensively on the chemical composition of the interface and its consequences for cell performance. The focus of this contribution is the microstructure of the interface, as well as the microstructural development during processing. On the fuel side, the interdiffusion of ceria and zirconia is known to lead to an intermixed phase with decreased conductivity. However, the reduced cell performance of anode-supported cells with Ni-GDC electrodes cannot be explained by an increase in the electrolyte resistance alone. We show that the formation of porosity due to a difference in the diffusion coefficients of ceria and zirconia leads to an increase in the fuel electrode polarization, and investigate possible countermeasures. It is shown that specifically the presence of NiO leads to the formation of porosity at the interface. On the air side, we investigate the role of a dense interdiffusion layer between ceria and zirconia on the air electrode polarization. We confirm that only a dense interdiffusion layer is necessary by using Pr-doped ceria as a barrier layer, which delaminates after sintering and leaves behind a submicron barrier layer. Finally, we investigate the hypothesis that the densification of the barrier layer during air electrode sintering is essential for electrode adhesion and performance.
11
Suzuki, Tatsumi, Chengchao Zhong, Keiji Shimoda, Ken'ichi Okazaki, and Yuki Orikasa. "(Digital Presentation) Electrochemical Impedance Analysis of Three-Electrode Cell with Solid Electrolyte/Liquid Electrolyte Interface." ECS Meeting Abstracts MA2023-02, no. 8 (December 22, 2023): 3369. http://dx.doi.org/10.1149/ma2023-0283369mtgabs.
Abstract:
Mechanical contact loss at the solid electrolyte/electrode interface in all-solid-state batteries, a type of next-generation battery, has been reported as a major issue for ion transport in all-solid-state batteries[1]. To improve this contact problem, it has been proposed to add a small amount of liquid electrolyte to the solid electrolyte/electrode interface[2]. However, the reported ion transport analysis at the solid electrolyte/liquid electrolyte interface is limited in semi-solid-state system using symmetrical cells with lithium metal as the working electrode[3]. In this study, charge transfer reactions at the solid electrolyte/liquid electrolyte interface were analyzed by impedance (EIS) measurements in a three-electrode cell with a solid/liquid electrolyte interface using a composite electrode containing a cathode active material as the working electrode. A composite electrode prepared by mixing LiCoO2:acetylene black:polyvinylidene fluoride in a weight ratio of 8:1:1, coating Al foil, drying and pressing was used as the working electrode, while lithium metal was used as the counter and reference electrodes. A NASICON-type solid electrolyte Li1+x+y Al x (Ti2−y Ge y )P3−z Si z O12 was constructed between the working electrode and the counter electrode, and a three-electrode cell prepared by filling the liquid electrolyte 1 M LiClO4/PC between the solid electrolyte and both electrodes. The reference electrode was placed between the solid electrolyte and the counter electrode, as the solid electrolyte/liquid electrolyte interface charge transfer is not observed in EIS measurements when the reference electrode is placed between the working electrode and the solid electrolyte. After two cycles of constant current charge/discharge measurements (current rate: 0.1 C rate, cut-off potential: 3.2 V - 4.2 V vs. Li/Li+), the solid electrolyte/liquid electrolyte interface charge transfer was analyzed by performing EIS measurements. To identify the semicircle associated with the solid electrolyte/liquid electrolyte interface resistance, measurements were also performed in a cell without a solid electrolyte and the resistance components corresponding to each semicircle were assigned. The temperature dependence of the observed semicircles was analyzed. A comparison of the activation energies calculated from the slopes of the Arrhenius plots confirmed a particularly large activation barrier at the solid electrolyte/liquid electrolyte interface and the working electrode/liquid electrolyte interface charge transfer. [1] R. Koerver, I. Aygun, T. Leichtweiss, C. Dietrich, W. Zhang, J.O. Binder, P. Hartmann, W.G. Zeier and J. Janek, Chem. Mater., 29, 5574-5582 (2017). [2] C. Wanga, Q. Suna, Y. Liua, Y. Zhaoa, X. Lia, X. Lina, M.N. Banisa, M. Lia, W. Lia, K.R. Adaira, D. Wanga, J. Lianga, R. Lia, L. Zhangb, R. Yangb, S. Lub and X. Suna, Nano Energy, 48, 35-43 (2018). [3] T. Abe, H. Fukuda, Y. Iriyama, Z. Ogumi, J. Electrochem. Soc., 151, A1120-A1123 (2004).
12
Musk, Elon. "An Integrated Brain-Machine Interface Platform With Thousands of Channels." Journal of Medical Internet Research 21, no. 10 (October 31, 2019): e16194. http://dx.doi.org/10.2196/16194.
Abstract:
Brain-machine interfaces hold promise for the restoration of sensory and motor function and the treatment of neurological disorders, but clinical brain-machine interfaces have not yet been widely adopted, in part, because modest channel counts have limited their potential. In this white paper, we describe Neuralink’s first steps toward a scalable high-bandwidth brain-machine interface system. We have built arrays of small and flexible electrode “threads,” with as many as 3072 electrodes per array distributed across 96 threads. We have also built a neurosurgical robot capable of inserting six threads (192 electrodes) per minute. Each thread can be individually inserted into the brain with micron precision for avoidance of surface vasculature and targeting specific brain regions. The electrode array is packaged into a small implantable device that contains custom chips for low-power on-board amplification and digitization: The package for 3072 channels occupies less than 23×18.5×2 mm3. A single USB-C cable provides full-bandwidth data streaming from the device, recording from all channels simultaneously. This system has achieved a spiking yield of up to 70% in chronically implanted electrodes. Neuralink’s approach to brain-machine interface has unprecedented packaging density and scalability in a clinically relevant package.
13
Weigel, Tobias, Julian Brennecke, and Jan Hansmann. "Improvement of the Electronic—Neuronal Interface by Natural Deposition of ECM." Materials 14, no. 6 (March 12, 2021): 1378. http://dx.doi.org/10.3390/ma14061378.
Abstract:
The foreign body reaction to neuronal electrode implants limits potential applications as well as the therapeutic period. Developments in the basic electrode design might improve the tissue compatibility and thereby reduce the foreign body reaction. In this work, the approach of embedding 3D carbon nanofiber electrodes in extracellular matrix (ECM) synthesized by human fibroblasts for a compatible connection to neuronal cells was investigated. Porous electrode material was manufactured by solution coelectrospinning of polyacrylonitrile and polyamide as a fibrous porogen. Moreover, NaCl represented an additional particulate porogen. To achieve the required conductivity for an electrical interface, meshes were carbonized. Through the application of two different porogens, the electrodes’ flexibility and porosity was improved. Human dermal fibroblasts were cultured on the electrode surface for ECM generation and removed afterwards. Scanning electron microscopy imaging revealed a nano fibrous ECM network covering the carbon fibers. The collagen amount of the ECM coating was quantified by hydroxyproline-assays. The modification with the natural protein coating on the electrode functionality resulted in a minor increase of the electrical capacity, which slightly improved the already outstanding electrical interface properties. Increased cell numbers of SH-SY5Y cell line on ECM-modified electrodes demonstrated an improved cell adhesion. During cell differentiation, the natural ECM enhanced the formation of neurites regarding length and branching. The conducted experiments indicated the prevention of direct cell-electrode contacts by the modification, which might help to shield temporary the electrode from immunological cells to reduce the foreign body reaction and improve the electrodes’ tissue integration.
14
Gross, Axel. "(Invited) The Electric Double Layer Revisited from an Atomistic Perspective." ECS Meeting Abstracts MA2023-02, no. 5 (December 22, 2023): 858. http://dx.doi.org/10.1149/ma2023-025858mtgabs.
Abstract:
At the interface between two conducting phases, an electric double layer (EDL) forms. In interfacial electrochemistry, such an EDL is present at the interface between the electrode and the electrolyte. The structure of the EDL can be crucial for all processes that occur at such interfaces, for example in electrochemical energy conversion and storage. Yet, it is fair to say that our understanding of the structure of the EDL is still limited and mainly based on concepts that are more than one hundred years old. In this contribution, I will focus on relatively simple interfaces between metallic electrodes and aqueous electrolytes [1] from a conceptual and from a quantum chemical atomistic perspective. I will discuss how elecrochemically control parameter such as the electrode potential and pH values can enter a first-principles description of electrochemical interfaces. Furthermore, I will present examples in which the explicit consideration of the electrochemical environment is not necessary in order to faithfully reproduce adsorbate structures on metal electrodes as a function of the electrochemical control parameters [2]. In addition, I will critically discuss the properties of electrochemical interfaces that correspond to observables from an atomistic perspective. [1] A. Groß and S. Sakong, Ab initio simulations of water/metal interfaces, Chem. Rev. 2022, 122, 10746. [2] A. Groß, Reversible vs. standard hydrogen electrode scale in interfacial electrochemistry from a theoretician's atomistic point of view, J. Phys. Chem. C 2022, 126, 11439.
15
Ruiz, Gabriel A., Martín L. Zamora, and Carmelo J. Felice. "Isoconductivity method to study adhesion of yeast cells to gold electrode." Journal of Electrical Bioimpedance 5, no. 1 (August 8, 2019): 40–47. http://dx.doi.org/10.5617/jeb.809.
Abstract:
AbstractIn this paper, we used impedance spectroscopy and gold electrodes to detect the presence of yeast cells and monitor the attachment of these cells to the electrodes. We analyzed the effect of conductivity changes of the medium and the attachment on the electrode-electrolyte interface impedance. A three-electrode cell was designed to produce a uniform electric field distribution on the working electrode and to minimize the counter electrode impedance. Moreover, we used a small AC overpotential (10 mV) to keep the system within the linear impedance limits of the electrode-electrolyte interface. This study proposes a new method to differentiate the impedance changes due to the attachment of yeast cells from those due to conductivity changes of the medium. The experiments showed that when the difference between the cell suspension and base solution conductivities is within the experimental error, the impedance changes are only due to the attachment of yeast cells to the electrodes. The experiments also showed a strong dependence (decrease) of the parallel capacity of the electrode electrolyte interface with the yeast cell concentration of suspension. We suggest that this decrease is due to an asymmetrical redistribution of surface charges on both sides of cell, which can be modeled as a biologic capacity connected in series with the double layer capacity of the interface. Our results could help to explain the rate of biofilm formation through the determination of the rate of cell adhesion.
16
Lehto, Danielle, Anna Claire, Peter Zacher, and Krysti Knoche Gupta. "Characterizing Recast Nafion® Film Electrode Interface Diffusion and Kinetics in a Non-Aqueous System." ECS Meeting Abstracts MA2022-01, no. 45 (July 7, 2022): 1926. http://dx.doi.org/10.1149/ma2022-01451926mtgabs.
Abstract:
The effect of recast Nafion® films on platinum working electrodes in acetonitrile will be characterized by cyclic voltammetry and rotating disk voltammetry. Until now, the behavior of recast Nafion® in a non-aqueous system has not been reported in this way. The behavior of recast Nafion® films in acetonitrile has been anecdotally observed to be different from the behavior in aqueous solutions, which have also been comprehensively studied1,2. The reversible redox couple of Tris(2,2′-bipyridine)ruthenium(II) hexafluorophosphate, Ru(bpy)3 2 ++, in an acetonitrile electrolyte solution will be compared between a bare platinum working electrode and a recast Nafion® film coated platinum working electrode by cyclic voltammetry. In cyclic voltammetry the convective mass transport of the species is limited only to the diffusion at the stationary electrode interface. In rotating the working electrode (RDE) the limitation on mass transport is extended beyond the stationary diffusion behavior. The current is dependent on and limited by the mass transport of the species to the electrode interface where it can undergo redox, the limiting current of both a bare platinum working electrode system and of a recast Nafion® film coated platinum working electrode will be observed by changing the rotation rate of the RDE. The diffusion interface of the electrode inside an acetonitrile solution of Ru(bpy)3 2 + and an electrolyte will be determined by rotating disk voltammetry at a bare platinum working electrode and at a recast Nafion® film coated platinum working electrode. The film solution interface thickness will be reported along with the effect on the diffusion of the interface between bare and recast Nafion® coated platinum working electrodes. 1. S. K. Zecevic et al 1997 J. Electrochem. Soc. 144 2973 2. T. A. Zowodzinski, S. Gottesfeld et al 1997 Advances in Electrochemical Sciences and Engineering
17
Vėbraitė, Ieva, Moshe David-Pur, David Rand, Eric Daniel Głowacki, and Yael Hanein. "Electrophysiological investigation of intact retina with soft printed organic neural interface." Journal of Neural Engineering 18, no. 6 (November 19, 2021): 066017. http://dx.doi.org/10.1088/1741-2552/ac36ab.
Abstract:
Abstract Objective. Understanding how the retina converts a natural image or an electrically stimulated one into neural firing patterns is the focus of on-going research activities. Ex vivo, the retina can be readily investigated using multi electrode arrays (MEAs). However, MEA recording and stimulation from an intact retina (in the eye) has been so far insufficient. Approach. In the present study, we report new soft carbon electrode arrays suitable for recording and stimulating neural activity in an intact retina. Screen-printing of carbon ink on 20 µm polyurethane (PU) film was used to realize electrode arrays with electrodes as small as 40 µm in diameter. Passivation was achieved with a holey membrane, realized using laser drilling in a thin (50 µm) PU film. Plasma polymerized 3.4-ethylenedioxythiophene was used to coat the electrode array to improve the electrode specific capacitance. Chick retinas, embryonic stage day 13, both explanted and intact inside an enucleated eye, were used. Main results. A novel fabrication process based on printed carbon electrodes was developed and yielded high capacitance electrodes on a soft substrate. Ex vivo electrical recording of retina activity with carbon electrodes is demonstrated. With the addition of organic photo-capacitors, simultaneous photo-electrical stimulation and electrical recording was achieved. Finally, electrical activity recordings from an intact chick retina (inside enucleated eyes) were demonstrated. Both photosensitive retinal ganglion cell responses and spontaneous retina waves were recorded and their features analyzed. Significance. Results of this study demonstrated soft electrode arrays with unique properties, suitable for simultaneous recording and photo-electrical stimulation of the retina at high fidelity. This novel electrode technology opens up new frontiers in the study of neural tissue in vivo.
18
Qin, G., Ya Xiong Liu, Z. X. Bai, H. Y. Wang, and R. K. Du. "Surface Modification on Polyurethane of Bio-Electrodes Implanted for Deep Brain." Materials Science Forum 697-698 (September 2011): 450–53. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.450.
Abstract:
For bio-electrodes implanted in deep brain, electrode materials will affect the fibrous encapsulation formed on the interface of bio-electrodes and brain tissue which would reduce the operating effect of the bio-electrodes. To reduce or eliminate the fibrous encapsulation layer, N2/H2 plasma treatment process is used to modify the polyurethane which is the most materials of the bio-electrode. The amino groups are produced on the polyurethane surface. After these amino groups have a polymerization reaction with the polypeptide molecule, a layer of the polypeptide molecule is formed on the polyurethane surface of the bio-electrode. These modified bio-electrodes are implanted in the deep brain of the rats for two weeks to observe the immune response and the morphology of the cells on the interface of the bio-electrodes. The results of the experiments indicate that the polypeptide molecules on the polyurethane can improve the immune response of the cells and affect the growth of the fibrous encapsulation on the interface of the bio-electrodes.
19
Hu, Anyang, and Feng Lin. "The Electrochemical Interface As a Reactive Environment to Re-Synthesize Electrode Surface Chemistry Using the Dissolution-Redeposition Dynamics." ECS Meeting Abstracts MA2022-02, no. 1 (October 9, 2022): 96. http://dx.doi.org/10.1149/ma2022-02196mtgabs.
Abstract:
The electrode-electrolyte interface governs the efficiency and life time of almost all electrochemical reactions. Essentially, this interface, as a geometrically confined environment, allows many interfacial reactions occurring and provides a versatile toolbox of tailoring electrode surface chemistry under operating conditions. Here, through synchrotron spectroscopic, microscopic, and imaging characterizations, using the electrochromic tungsten trioxide (WO3) in an acidic electrolyte as the research platform, we reveal that the performance degradation is related to electrode material morphology evolution, phase transformation, and charge heterogeneity. We experimentally demonstrate that WO3 dissolution and redeposition across the electrochemical interface trigger all these evolutions. The redeposition process provokes the in situ crystal growth, inducing the evolution from the semicrystalline WO3 to the single-crystalline, nanoflake-shaped, proton-trapped tungsten trioxide di-hydrate (H x WO3·2H2O). Importantly, as a ubiquitous phenomenon, transition metal dissolution will form the diffusion layer at the interface. We have established a novel experimental design to probe and understand how the dissolved transition metal species evolve in the diffusion layer. The thickness of the diffusion layer is up to tens of micrometers, and the local electronic structure of dissolved species varies with the distance from the electrode surface. Furthermore, this dynamic dissolution and redeposition feature can be manipulated to regulate the chemical composition and crystal structure of the electrode surface as well as the overall electrochemical performance. Foreign cations (e.g., Ti4+), either added as electrolyte additives or dissolved from surface coatings, can rapidly participate in the electrode dissolution-redeposition process and facilitate the establishment of the dissolution-redeposition equilibrium, thereby alleviating W net dissolution, modulating the electrode morphology, and improving the Coulombic efficiency and cycling stability during long-term electrochemical reactions. Therefore, our systematic study demonstrates that it is feasible to exploit the intertwined dissolution-redeposition kinetics between oxide surface coatings and electrodes in aqueous electrolytes to extend control over electrochemical interfacial reactions. Electrode surface chemistry can be re-synthesized in terms of regulating the dynamic structural evolution of electrode surface and the correlatively developing speciation at the interface, which highlights the significance of more fundamental investigations at the electrode-electrolyte interfaces.
20
Edwards, C. A., P. A. Finger, D. J. Anderson, J. A. Wiler, J. F. Hetke, and R. A. Altschuler. "A Technique for In Vivo Morphological Evaluation of Chronically Implanted Neuronal Silicon Substrate Electrodes for Confocal Microscopy." Microscopy and Microanalysis 3, S2 (August 1997): 351–52. http://dx.doi.org/10.1017/s1431927600008643.
Abstract:
Various multichannel silicon electrodes have been developed for stimulating and recording in the central nervous system of experimental animals. These electrodes can be used in their planar form or can be assembled into 3-D structures for volume interaction with tissue. However, bio-compatibility issues arise concerning the introduction of any electrode into living tissue. From earlier observations, we noticed that the neuronal cells had a tendency to adhere to the chronically implanted silicon substrate. Routine microtechnique became an obstacle when attempting to section the implanted and embedded electrode. Most often, this was attempted by passing a stainless steel blade through paraffin, or plastic embedded tissue, resulting in disrupting the tissue material interface. We needed to develop a reproducible procedure which preserved the integrity of this interface for future LM and confocal microscopic studies.In order to preserve the electrode/tissue interface, we used the Exakt microgrinding/micropolishing technique, where the electrode/brain block was embedded in Technovit 7200 resin and cut with a diamond impregnated band saw.
21
Ers, Heigo, Liis Siinor, and Piret Pikma. "The Puzzling Processes at Electrode | Ionic Liquid Interface." ECS Meeting Abstracts MA2022-02, no. 60 (October 9, 2022): 2533. http://dx.doi.org/10.1149/ma2022-02602533mtgabs.
Abstract:
J.M. Lehn stated in his Nobel prize lecture in 1988 that supramolecular chemistry is the chemistry of the intermolecular bond, covering the structure and functions of entities formed by the association of two or more chemical species [1]. The adsorption of organic molecules is the net result of the interactions between the molecules and the two phases, the metal and the electrolyte, and the interactions between the latter two. To this day, the universal understanding that the adsorption of organic molecules results in the formation of an ordered monolayer is based on the phenomenon observed in mainly aqueous solutions. However, the conception might not be straightforwardly transferrable to the organic additive + ionic liquid | electrode interface. For example, the existence of an interfacial multilayer structure of pure IL ions in contrast with an aqueous electrolyte has been previously shown in both experimental and computational studies. Furthermore, it has been shown that in ILs, if the ions form rigid layers on the electrode, it is necessary to apply an overpotential for interfacial restructuring. Therefore, studying the adsorption of organic additives in ionic liquids (IL) should contribute to a better understanding of metal | IL interfaces. In the given presentation we overview the characteristics of solid-liquid interface characteristics of various additives from ionic liquid media at different electrodes. Cyclic voltammetry, electrochemical impedance spectroscopy and in situ scanning tunnelling microscopy measurements were conducted to characterize the electrochemical behavior of the self-assembled layers of 4,4’-bipyridine (4,4’-BP) and 2,2’-bipyridine (2,2’-BP) at the Sb(111) | x-BP+1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) interface [2-3]. The specific adsorption of iodide ions was studied at Bi(111), Cd(0001) and pyrolytic graphite electrodes [4-6]. All the experiments were carried out in a three-electrode electrochemical cell in a glovebox. The halide ions are surface active ions with specific adsorption behavior [4-6]. The strong specific adsorption of halide ions at single crystal electrodes, as well as other electrodes, is a complicated process due to the partial charge transfer between adsorbed ions and the solid electrode surface. The properties of the adsorption layer depend on the electrode potential and the concentration of the surface-active ions in an electrolyte. The theory that the adsorption of organic molecules results in SAM formation is mainly based on the results observed in aqueous solutions. However, these findings may not be as straightforwardly linkable to the organic additive + ionic liquid | electrode interface. The analysis of cyclic voltammetry and impedance results revealed that 2,2′-BP and 4,4′-BP indeed adsorb at the Sb(111) interface, forming a thin dielectric layer at the electrode surface, confirmed by in situ STM measurements, resulting in the differential capacitance values nearly two times lower compared to EMImBF4. Acknowledgments: This work was supported by the Estonian Research Council grant PSG249, and by the EU through the European Regional Development Fund under project TK141 (2014-2020.4.01.15-0011). References: [1] Lehn, J.-M., Angew. Chem. Int. Ed. Engl. 1988, 27 (1), 89–112. [2] Pikma et al., Electrochem. Commun. 2015, 61 (Supplement C), 61–65. [3] H. Ers et al., Electrochim. Acta 2022, 421, 140468. [4] H. Ers et al., J. Electroanal. Chem. 2021, 903, 115826. [5] L. Siinor et al., Electrochem. Commun. 2013, 35, 5–7. [6] L. Siinor et al., J. Electroanal. Chem. 2014, 719, 133–137.
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CHEN, KUNFENG, FEI LIU, XITONG LIANG, and DONGFENG XUE. "SURFACE–INTERFACE REACTION OF SUPERCAPACITOR ELECTRODE MATERIALS." Surface Review and Letters 24, no. 03 (March 30, 2017): 1730005. http://dx.doi.org/10.1142/s0218625x17300052.
Abstract:
Facing the challenge of low energy density of conventional electric double layer supercapacitors, researchers have long been focusing on the development of novel pseudocapacitive electrode materials with higher energy densities. Since capacitive charge storage reaction mostly occurs on the interface of electrode and electrolyte, the interface chemistry determines the achievable power and energy densities of a supercapacitor. Consequently, understanding of surface–interface reaction mechanism is a key towards efficient design of high-performance supercapacitor electrode materials. In this paper, we have reviewed the recent advances in the understanding of surfaces–interfaces in the system of pseudocapacitive supercapacitors. With significant research advancements in the understanding of surface–interface of supercapacitors, novel colloidal electrode materials with improved surface–interface structures have been developed in our previous work, which have the potential to deliver both high energy and power densities. This review aims to provide an in-depth analysis on the surface–interface control approaches to improve the energy and power densities of supercapacitors.
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Aziz, Jamal, Honggyun Kim, Shania Rehman, Muhammad Farooq Khan, and Deok-kee Kim. "Chemical Nature of Electrode and the Switching Response of RF-Sputtered NbOx Films." Nanomaterials 10, no. 11 (October 29, 2020): 2164. http://dx.doi.org/10.3390/nano10112164.
Abstract:
In this study, the dominant role of the top electrode is presented for Nb2O5-based devices to demonstrate either the resistive switching or threshold characteristics. These Nb2O5-based devices may exhibit different characteristics depending on the selection of electrode. The use of the inert electrode (Au) initiates resistive switching characteristics in the Au/Nb2O5/Pt device. Alternatively, threshold characteristics are induced by using reactive electrodes (W and Nb). The X-ray photoelectron spectroscopy analysis confirms the presence of oxide layers of WOy and NbOx at interfaces for W and Nb as top electrodes. However, no interface layer between the top electrode and active layer is detected in X-ray photoelectron spectroscopy for Au as the top electrode. Moreover, the dominant phase is Nb2O5 for Au and NbO2 for W and Nb. The threshold characteristics are attributed to the reduction of Nb2O5 phase to NbO2 due to the interfacial oxide layer formation between the reactive top electrode and Nb2O5. Additionally, reliability tests for both resistive switching and threshold characteristics are also performed to confirm switching stabilities.
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Goyal, Krittika, David A. Borkholder, and Steven W. Day. "Dependence of Skin-Electrode Contact Impedance on Material and Skin Hydration." Sensors 22, no. 21 (November 4, 2022): 8510. http://dx.doi.org/10.3390/s22218510.
Abstract:
Dry electrodes offer an accessible continuous acquisition of biopotential signals as part of current in-home monitoring systems but often face challenges of high-contact impedance that results in poor signal quality. The performance of dry electrodes could be affected by electrode material and skin hydration. Herein, we investigate these dependencies using a circuit skin-electrode interface model, varying material and hydration in controlled benchtop experiments on a biomimetic skin phantom simulating dry and hydrated skin. Results of the model demonstrate the contribution of the individual components in the circuit to total impedance and assist in understanding the role of electrode material in the mechanistic principle of dry electrodes. Validation was performed by conducting in vivo skin-electrode contact impedance measurements across ten normative human subjects. Further, the impact of the electrode on biopotential signal quality was evaluated by demonstrating an ability to capture clinically relevant electrocardiogram signals by using dry electrodes integrated into a toilet seat cardiovascular monitoring system. Titanium electrodes resulted in better signal quality than stainless steel electrodes. Results suggest that relative permittivity of native oxide of electrode material come into contact with the skin contributes to the interface impedance, and can lead to enhancement in the capacitive coupling of biopotential signals, especially in dry skin individuals.
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Yawar, Abbas, Mi Ra Park, Quanli Hu, Woo Jin Song, Tae-Sik Yoon, Young Jin Choi, and Chi Jung Kang. "Investigation of Switching Phenomenon in Metal-Tantalum Oxide Interface." Journal of Nanoscience and Nanotechnology 15, no. 10 (October 1, 2015): 7564–68. http://dx.doi.org/10.1166/jnn.2015.11133.
Abstract:
To investigate the nature of the switching phenomenon at the metal-tantalum oxide interface, we fabricated a memory device in which a tantalum oxide amorphous layer acted as a switching medium. Different metals were deposited on top of the tantalum oxide layer to ensure that they will react with some of the oxygen contents already present in the amorphous layer of the tantalum oxide. This will cause the formation of metal oxide (MOx) at the interface. Two devices with Ti and Cu as the top electrodes were fabricated for this purpose. Both devices showed bipolar switching characteristics. The SET and RESET voltages for the Ti top electrode device were ∼+1.7 V and ∼−2 V, respectively, whereas the SET and RESET voltages for the Cu top electrode device were ∼+0.9 V and ∼−0.9 V, respectively. In the high-resistance state (HRS) conduction, the mechanisms involved in the devices with Ti and Cu top electrodes were space-charge limited conduction (SCLC) and ohmic, respectively. On the other hand, in the low-resistance state (LRS), the Ti top electrode device undergoes SCLC at a high voltage and ohmic conduction at a low voltage, and the Cu top electrode again undergoes ohmic conduction. From the consecutive sweep cycles, it was observed that the SET voltage gradually decreased with the sweeps for the Cu top electrode device, whereas for the Ti top electrode device, the set voltage did not vary with the sweeps.
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Guo, Liang. "Stretchable Polymeric Neural Electrode Array: Toward a Reliable Neural Interface." MRS Proceedings 1795 (2015): 1–12. http://dx.doi.org/10.1557/opl.2015.567.
Abstract:
ABSTRACTConducting polymers are often employed as coatings on smooth metal electrodes to improve the electrode performance with respect to the signal-to-noise ratio for neural recording, charge-injection capacity for neural stimulation, and inducement of neural growth for electrode-tissue integration. However, adhesion of conducting polymer coatings on metal electrodes is poor, making the coating less durable and the electrical property of the electrode less stable. Moreover, conventional conducting polymers have relative low conductance, preventing their direct use as the electrode and lead material; and they are brittle, making it difficult for flexible neural electrodes to incorporate conducting polymer coatings. We have developed a new polypyrrole/polyol-borate composite film with concurrent excellent electrical and mechanical properties. We further developed a method to fabricate a stretchable multielectrode array using this new material as the sole conductor for both electrodes and leads, in contrast with the conventional approach of incorporating conducting polymers only through coating on non-stretchable metal electrodes. The resulting stretchable polymeric multielectrode array (SPMEA) was stretchable up to 23% uniaxial tensile strain with minimal losses in electrical conductivity. Electrochemical testing revealed the SPMEA’s impressive advantage for recording local field neural potentials and for epimysial stimulation of denervated skeletal muscles. As a neural interface engineer, I would also like to compare the compliant neural interfacing technology to other technologies, such as optogenetics, radiogenetics, and even a living neural interface that is currently under development in our lab.
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Yang, Gaoqiang, ChungHyuk Lee, Siddharth Komini Babu, Ulises Martinez, Xiaojing Wang, and Jacob S. Spendelow. "Tuning Electrode-Membrane Interface for Highly Efficient Polymer Electrolyte Membrane Fuel Cells." ECS Meeting Abstracts MA2022-01, no. 35 (July 7, 2022): 1419. http://dx.doi.org/10.1149/ma2022-01351419mtgabs.
Abstract:
Polymer electrolyte membrane fuel cells (PEMFCs) are typically comprised of porous electrodes with randomly distributed mixtures of Pt/C catalyst and ionomer formed during the ink deposition process. The randomness of catalyst particles, ionomer films, and voids, create a non-ideal disordered electrode structure with high tortuosity. These intrinsic characteristics of conventional electrodes create significant challenges during PEMFC operation. These challenges include: 1) low catalyst utilization; 2) high O2 transport resistance to catalyst through the ionomer and pores of carbon support; and 3) limited electronic/protonic conductivities. To improve the performance of the PEMFC electrode, we have previously shown that structured electrodes based on a patterned membrane surface can increase the interfacial area between the electrode and the membrane, enhancing mass transport at high current densities, and augmenting its ionic conductivity.[1][2] In this work, we will present further optimization of these type of structured electrodes using free-standing architectures, reduced ionomer content, and new catalyst deposition processes. More importantly, these newly tuned electrode structures can improve the performance of PEMFCs by maximizing three-phase boundaries and optimizing the electron, proton, gas, and water transport paths. Acknowledgement: We gratefully acknowledge support from the Laboratory Directed Research & Development Program at Los Alamos National Laboratory. Reference: [1] S. K. Babu, R. Mukundan, D. A. Cullen, and J. S. Spendelow, “Co-Axial Nafion Nanowire Electrode.” ECS, Oct. 15, 2019. [2] S. K. Babu, J. S. Spendelow, and R. L. Borup, “Meso-Structured Array Electrode for Polymer Electrolyte Fuel Cells.” ECS, Oct. 03, 2017.
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Foroutan Koudahi, Masoud, and Elzbieta Frackowiak. "The Electrode/Electrolyte Interface in MXene-Based Electrochemical Capacitors." ECS Meeting Abstracts MA2023-02, no. 60 (December 22, 2023): 2906. http://dx.doi.org/10.1149/ma2023-02602906mtgabs.
Abstract:
The operating voltage of electrochemical capacitor (EC) in aqueous medium is considerably limited due to the theoretical stability of water (1.23V). Hence, the delivered energy density of such systems is restricted compared to that of batteries. A traditional approach to tackle this issue is to focus on improving the capacitance rather than the working voltage of ECs. Especially, combining traditionally used carbons with pseudocapacitive materials has been investigated by many researchers. Adopting this strategy improves the delivered capacity of the system, but key metrics such as a power performance and cycle life of ECs may face a serious failure. The slow nature of faradaic reactions affects the frequency response, while the parasitic activities downgrades the favorable cyclability of the device. Hence, a realistic pathway to improve the energy performance of ECs must be taken. Transition metal carbides, carbonitrides, and nitrides (MXenes) are a new family of 2D layered materials. They have the general formula of Mn+1Xn, in which M indicates the transition metal, like Ti, Mo, Nb, etc., and X is carbon or nitrogen. Considering favorable properties such as a high conductivity and the ability of cation intercalation, many ECs designs based on MXenes have been reported. Nevertheless, there is a lack of clear elucidation of the charge storage mechanism in these materials. Here, the interface of electrode-electrolyte was studied to gain a better insight into the hydrogen storage mechanism and overpotential of MXenes (Ti3C2Tx) in acidic and neutral media. It has been found that MXene-based ECs are suffering from an unbalanced capacitive performance between negative and positive electrodes. Especially, a low capacitance in the positive potential range limits the cell voltage to 0.8V and 1.3V in 1M H2SO4 and 1M Li2SO4, respectively. To extend the cell voltage, self-standing composites based on 3D graphene and Ti3C2Tx were designed. Interestingly, it was observed that during the negative polarization, a significant redox couple activity was observed at the surface of 3DG/ Ti3C2Tx composite electrode. The working potential of the positive electrode was enlarged using micro/mesoporous Black Pearl (BP2000) as electrode material. The realized asymmetric cell was operated in a wider potential window. A higher expansion was realized after balancing the charge of both electrodes. The addition of redox-active salt (KI) to the electrolyte medium improved the capacitive performance of the positive electrode, due to the activity of iodide/iodine species. Excessive increase of the positive electrode capacity was further equalized by balancing the mass of electrodes. In the neutral medium, an asymmetric design of the cell based on Ti3C2Tx (negative electrode) and BP2000 (positive electrode) allowed the cell to operate in a broad range of voltage (up to 2V) with a stable cycling (more than 7000 cycles). The prepared electrodes were characterized using different physiochemical techniques, including XRD, XPS, BET, and SEM analyses. For the electrochemical characterization in two and three-electrode cells, electrodes in the form of pellets or self-standing discs were utilized. The performance of EC cells was studied by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.
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Zhang, Lei, Binyuan Zhang, Liwei Jiang, and Yisong Zheng. "Giant magnetoresistance in spin valves realized by substituting Y-site atoms in Heusler lattice." Journal of Physics: Condensed Matter 34, no. 20 (March 10, 2022): 204003. http://dx.doi.org/10.1088/1361-648x/ac5779.
Abstract:
Abstract ‘All-Heusler’ spin-valve constructed by two half-metallic Heusler electrodes and a non-magnetic Heusler spacer contains two interfaces that have a crucial influence on the magnetoresistance. In order to reduce the disorder at the interface and protect the half metallicity of the electrode at the same region, we propose a scheme to construct a spin valve by replacing the Y-site atoms in the half-metallic Heusler electrode to obtain the corresponding non-magnetic spacer based on the Slater–Pauling rule. In this way, the lattice and band match of the two materials can be ensured naturally. By using Co2FeAl as electrode and Co2ScAl as the spacer materials, we construct the Co2FeAl/Co2ScAl/Co2FeAl(001)-spin valve. Based on the first-principles calculation, the most stable FeAl/CoCo-interface is determined both from the phonon spectra and the formation energy when the spacer Co2ScAl grows on the FeAl-terminated (001) surface of electrode material Co2FeAl. By comparing the projected density of states of the interfacial atoms with the corresponding density of states of the bulk electrode material, only the value of spin-up state of Al changes from 0.17 states/atom/eV to 0.06 states/atom/eV before and after substitution, the half metallicity at the interface is maintained. As a result, the spin-dependent transport properties show significant theoretical magnetoresistance MRop which can reach up to 1010% and much larger than 106% reported before.
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Vermaas, M., M. C. Piastra, T. F. Oostendorp, N. F. Ramsey, and P. H. E. Tiesinga. "FEMfuns: A Volume Conduction Modeling Pipeline that Includes Resistive, Capacitive or Dispersive Tissue and Electrodes." Neuroinformatics 18, no. 4 (April 18, 2020): 569–80. http://dx.doi.org/10.1007/s12021-020-09458-8.
Abstract:
Abstract Applications such as brain computer interfaces require recordings of relevant neuronal population activity with high precision, for example, with electrocorticography (ECoG) grids. In order to achieve this, both the placement of the electrode grid on the cortex and the electrode properties, such as the electrode size and material, need to be optimized. For this purpose, it is essential to have a reliable tool that is able to simulate the extracellular potential, i.e., to solve the so-called ECoG forward problem, and to incorporate the properties of the electrodes explicitly in the model. In this study, this need is addressed by introducing the first open-source pipeline, FEMfuns (finite element method for useful neuroscience simulations), that allows neuroscientists to solve the forward problem in a variety of different geometrical domains, including different types of source models and electrode properties, such as resistive and capacitive materials. FEMfuns is based on the finite element method (FEM) implemented in FEniCS and includes the geometry tessellation, several electrode-electrolyte implementations and adaptive refinement options. The code of the pipeline is available under the GNU General Public License version 3 at https://github.com/meronvermaas/FEMfuns. We tested our pipeline with several geometries and source configurations such as a dipolar source in a multi-layer sphere model and a five-compartment realistically-shaped head model. Furthermore, we describe the main scripts in the pipeline, illustrating its flexible and versatile use. Provided with a sufficiently fine tessellation, the numerical solution of the forward problem approximates the analytical solution. Furthermore, we show dispersive material and interface effects in line with previous literature. Our results indicate substantial capacitive and dispersive effects due to the electrode-electrolyte interface when using stimulating electrodes. The results demonstrate that the pipeline presented in this paper is an accurate and flexible tool to simulate signals generated on electrode grids by the spatiotemporal electrical activity patterns produced by sources and thereby allows the user to optimize grids for brain computer interfaces including exploration of alternative electrode materials/properties.
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Zhang, Yingjie. "(Invited) Molecular Imaging of the Local Solvation, Nucleation and Growth Processes at Electrode-Electrolyte Interfaces." ECS Meeting Abstracts MA2023-02, no. 60 (December 22, 2023): 2904. http://dx.doi.org/10.1149/ma2023-02602904mtgabs.
Abstract:
Electrochemical energy storage is a complex process that requires the synergistic participation of electrodes, electrolytes, and separators in the system. However, the key energy storage functions usually depend critically on the electrode-electrolyte interfaces, which include both the electrode surface and the electrical double layers (EDLs). Here I will discuss our efforts on developing and using electrochemical 3D atomic force microscopy (EC-3D-AFM) to simultaneously image the electrode and EDLs under operando conditions, with atomic-scale resolution. We study the interface between graphite electrode and various types of electrolytes. We observe rich EDL reconfiguration effects at different electrode potentials, which we find to be directly responsible for the capacitive charge storage functions. As the electrode potential goes beyond the electrochemical stability window of the electrolyte, we observe nucleation and growth processes where the EDLs and the deposited solid clusters exhibit intertwined structures. Such initial stage of electrode processes is likely connected to the long-term cycling behaviors of batteries.
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Cuong, Nguyen Tien, Mohd Ambri Mohamed, Nobuo Otsuka, and Dam Hieu Chi. "Reconstruction and Electronic Properties of Interface between Carbon Nanotubes and Ferromagnetic Co Electrodes." Applied Mechanics and Materials 229-231 (November 2012): 183–87. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.183.
Abstract:
The reconstruction and electronic structures of the interfaces between single wall carbon nanotubes and ferromagnetic Co electrodes were studied in the framework of density functional theory. The obtained results revealed that there is a strong interaction between carbon nanotubes and Co electrodes. At the interface region, Top layers of Co surface have been significantly reconstructed. The nature of chemical bonds at the Co-C interface is covalent bonding. The increase of the electron density occurs mainly at the interface where a substantial concentration of electron accumulates in Co-C bonds. A small amount of charge transfer from Co electrode to carbon nanotube junction was found. In addition, the spin polarization of Co atoms at the interface region has been suppressed due to the interaction with a carbon nanotube. It implies that the spin transport through this layer is low, which results in the small hysteretic magneto-resistance of carbon nanotube devices.
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Papadas, Ioannis T., Fedros Galatopoulos, Gerasimos S. Armatas, Nir Tessler, and Stelios A. Choulis. "Nanoparticulate Metal Oxide Top Electrode Interface Modification Improves the Thermal Stability of Inverted Perovskite Photovoltaics." Nanomaterials 9, no. 11 (November 14, 2019): 1616. http://dx.doi.org/10.3390/nano9111616.
Abstract:
Solution processed γ-Fe2O3 nanoparticles via the solvothermal colloidal synthesis in conjunction with ligand-exchange method are used for interface modification of the top electrode in inverted perovskite solar cells. In comparison to more conventional top electrodes such as PC(70)BM/Al and PC(70)BM/AZO/Al, we show that incorporation of a γ-Fe2O3 provides an alternative solution processed top electrode (PC(70)BM/γ-Fe2O3/Al) that not only results in comparable power conversion efficiencies but also improved thermal stability of inverted perovskite photovoltaics. The origin of improved stability of inverted perovskite solar cells incorporating PC(70)BM/ γ-Fe2O3/Al under accelerated heat lifetime conditions is attributed to the acidic surface nature of γ-Fe2O3 and reduced charge trapped density within PC(70)BM/ γ-Fe2O3/Al top electrode interfaces.
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Cann, David P., and Clive A. Randall. "Thermochemistry and electrical contact properties at the interface between semiconducting BaTiO3 and (Au–Ti) electrodes." Journal of Materials Research 12, no. 7 (July 1997): 1685–88. http://dx.doi.org/10.1557/jmr.1997.0231.
Abstract:
The interfacial characteristics of positive temperature coefficient of resistance (PTCR) BaTiO3-electrode interfaces were studied. Sessile drop wetting experiments in combination with measurements of the contact resistance of the interface were used to establish a fundamental perspective of the electrode-ceramic interface. It was shown that the thermodynamic work of adhesion Wad), which is the sum of the strengths of chemical interactions present at the interface, can be manipulated by the addition of chemically active elements to the electrode metal which enhance adhesion. This same procedure is shown to modify the important electrical interfacial properties such as the contact resistance.
35
Zhang, Yong, Baohua Wen, Liang Ma, and Xiaolin Liu. "Determination of damage zone in fatigued lead zirconate titanate ceramics by complex impedance analysis." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, CICMT (September 1, 2012): 000592–96. http://dx.doi.org/10.4071/cicmt-2012-tha22.
Abstract:
The electric properties of the modified lead zirconnate titanate ceramics with different fatigue cycles were studied over a temperature range of 300 to 550 °C. Combination of impedance and conductivity plots was utilized to understand the contributions arising from different regions in the PZT ceramics, i.e. the grain boundary and ceramic-electrode interface region. The results showed that both the dc conductivity of the ceramic-electrode interface and the dc conductivity of the grain boundary decrease with increasing cycle number. And the dc conductivity of the ceramic-electrode interface decreases larger during the fatigue process. Based on these results, we deduce that the damage zones underneath the electrodes are the main source of fatigue in ceramics.
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Liu, Junchen, Sen Lin, Wenzheng Li, Yanzhen Zhao, Dingkun Liu, Zhaofeng He, Dong Wang, Ming Lei, Bo Hong, and Hui Wu. "Ten-Hour Stable Noninvasive Brain-Computer Interface Realized by Semidry Hydrogel-Based Electrodes." Research 2022 (March 10, 2022): 1–12. http://dx.doi.org/10.34133/2022/9830457.
Abstract:
Noninvasive brain-computer interface (BCI) has been extensively studied from many aspects in the past decade. In order to broaden the practical applications of BCI technique, it is essential to develop electrodes for electroencephalogram (EEG) collection with advanced characteristics such as high conductivity, long-term effectiveness, and biocompatibility. In this study, we developed a silver-nanowire/PVA hydrogel/melamine sponge (AgPHMS) semidry EEG electrode for long-lasting monitoring of EEG signal. Benefiting from the water storage capacity of PVA hydrogel, the electrolyte solution can be continuously released to the scalp-electrode interface during used. The electrolyte solution can infiltrate the stratum corneum and reduce the scalp-electrode impedance to 10 kΩ-15 kΩ. The flexible structure enables the electrode with mechanical stability, increases the wearing comfort, and reduces the scalp-electrode gap to reduce contact impedance. As a result, a long-term BCI application based on measurements of motion-onset visual evoked potentials (mVEPs) shows that the 3-hour BCI accuracy of the new electrode (77% to 100%) is approximately the same as that of conventional electrodes supported by a conductive gel during the first hour. Furthermore, the BCI system based on the new electrode can retain low contact impedance for 10 hours on scalp, which greatly improved the ability of BCI technique.
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Sharma, Mohita, Yolanda Alvarez-Gallego, Wafa Achouak, Deepak Pant, Priyangshu M. Sarma, and Xochitl Dominguez-Benetton. "Electrode material properties for designing effective microbial electrosynthesis systems." Journal of Materials Chemistry A 7, no. 42 (2019): 24420–36. http://dx.doi.org/10.1039/c9ta04886c.
Abstract:
(a) Pictograph and (b) schematic representation of the placement of multiple working electrodes with a single counter electrode and reference electrode using an N'Stat setup and (c) the schematic of the potentiostat interface connection with the electrochemical cell.
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Tang, Yue, Ronghui Chang, Limin Zhang, and Feng Yan. "An Interference Suppression Method for Non-Contact Bioelectric Acquisition." Electronics 9, no. 2 (February 8, 2020): 293. http://dx.doi.org/10.3390/electronics9020293.
Abstract:
For non-contact bioelectrical acquisition, a new interference suppression method, named ‘noise neutralization method’, is proposed in this paper. Compared with the traditional capacitive driven-right-leg method, the proposed method is characterized with that there is an optimal gain to achieve the minimum interference output whatever for the electrode interface impedance mismatch caused by body motion and is more effective for smaller reference electrode areas. The performance of traditional capacitive driven-right-leg method is analyzed and the difficulty to suppress interference in the case of the interface impedance mismatch is pointed out. Therefore, a noise neutralization method is proposed by applying the reference electrode and a 50 Hz band-pass filter to obtain the interference of the human body and adapting the gains to neutralize the interference inputs of two acquisition electrodes and achieve the minimum interference output. The performance of the proposed method is theoretically analyzed and verified by the experiment results, which shows that the proposed method has similar performance to that of the traditional capacitive driven-right-leg method with electrode interface impedance match, while has better interference suppression ability with electrode interface impedance mismatch caused by body motion. It is suggested that the proposed method can be preferred in the case of limited reference electrode area or interface impedance mismatch.
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Lenser, Christian, Alexander Schwiers, Denise Ramler, and Norbert H. Menzler. "Investigation of the Electrode-Electrolyte Interfaces in Solid Oxide Cells." ECS Transactions 111, no. 6 (May 19, 2023): 1699–707. http://dx.doi.org/10.1149/11106.1699ecst.
Abstract:
The interface between electrodes and electrolyte in a solid oxide cell (SOC) are critical locations for cell performance. These interfaces originate from the chemical interaction of two different materials during processing. Different mechanisms can degrade cell performance on the air and fuel side, which necessitates different approaches to mitigate these effects. Here, materials interaction during processing is discussed for selected materials on the air side of an SOC. A new approach to obtain barrier layers of doped ceria with submicron thickness is introduced, and it is confirmed that only the interdiffusion layer between ceria and zirconia is necessary to prevent the formation of SrZrO3. Furthermore, the effect of the microstructure of a GDC layer on the sintering of a perovskite air electrode in this layer is investigated. It is demonstrated that the morphology of the GDC layer has an impact on the quality of the interface between air electrode and barrier layer.
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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.
Abstract:
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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Kucinskis, Gints, Beate Kruze, Prasad Korde, Anatolijs Sarakovskis, Arturs Viksna, Julija Hodakovska, and Gunars Bajars. "Enhanced Electrochemical Properties of Na0.67MnO2 Cathode for Na-Ion Batteries Prepared with Novel Tetrabutylammonium Alginate Binder." Batteries 8, no. 1 (January 14, 2022): 6. http://dx.doi.org/10.3390/batteries8010006.
Abstract:
Both the binder and solid–electrolyte interface play an important role in improving the cycling stability of electrodes for Na-ion batteries. In this study, a novel tetrabutylammonium (TBA) alginate binder is used to prepare a Na0.67MnO2 electrode for sodium-ion batteries with improved electrochemical performance. The ageing of the electrodes is characterized. TBA alginate-based electrodes are compared to polyvinylidene fluoride- (PVDF) and Na alginate-based electrodes and show favorable electrochemical performance, with gravimetric capacity values of up to 164 mAh/g, which is 6% higher than measured for the electrode prepared with PVDF binder. TBA alginate-based electrodes also display good rate capability and improved cyclability. The solid–electrolyte interface of TBA alginate-based electrodes is similar to that of PVDF-based electrodes. As the only salt of alginic acid soluble in non-aqueous solvents, TBA alginate emerges as a good alternative to PVDF binder in battery applications where the water-based processing of electrode slurries is not feasible, such as the demonstrated case with Na0.67MnO2.
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Larson, Karl, Eric A. Carmona, and Paul Albertus. "High Areal Capacity Cycling of Three-Electrode Sodium/NBA/Sodium Cells." ECS Meeting Abstracts MA2023-02, no. 5 (December 22, 2023): 851. http://dx.doi.org/10.1149/ma2023-025851mtgabs.
Abstract:
The cycling stability of Li and Na metal electrodes is influenced by the interface with the solid electrolyte. Study of the cycling behavior at areal capacities >>0.5 mAh/cm2 are uncommon, and plating and stripping behaviors remain relatively unknown for the individual electrode/electrolyte interfaces because of the difficulty of separating the individual interfaces in a two-electrode cell configuration. Because areal capacities of practical cells target >5 mAh/cm2, it is important to cycle at much higher areal capacities than typically studied. Here, we utilize a three-electrode symmetric cell of sodium metal with sodium beta alumina (NBA) electrolyte and cycled areal capacities ranging from 0.5 to 5 mAh cm-2 and achieved current densities >10 mA cm-2 at 1.0 mAh cm-2. We find that polarization increases most at the stripping electrode, and that during current density ramps the polarizations are greatly affected by the areal capacity, affecting the maximum current density that can be reached prior to either cell shorting or impedance rise that drives the voltage magnitude to well over 1 V. Additionally, we found resistance rise occurring at the Na/NBA interface during plate (reduction) as well as strip (oxidation) for the same electrode, potentially indicating voiding on plate at sufficiently high current densities and areal capacities (5 mAh cm-2, >2 mA cm-2). For two-electrode studies, the voltage evolution on the plating electrode we observe must be considered for the assumption that the plating electrode is a pseudo reference electrode. We also use our three-electrode cell configuration to study several other experimental conditions, including cycling to failure at a fixed current density and areal capacity, as well as a uni-directional current flow experiment to determine the maximum amount of plating / stripping that can be achieved in the absence of cycling. These findings will help direct future experiments and interpretation of data to quantify the limits and improve the engineering of Li and Na metal / solid electrolytes interfaces. Jolly, D. S.; Ning, Z.; Darnbrough, J. E.; Kasemchainan, J.; Hartley, G. O.; Adamson, P.; Armstrong, D. E. J.; Marrow, J.; Bruce, P. G. Sodium/Na Β″ Alumina Interface: Effect of Pressure on Voids. ACS Appl Mater Interfaces 2019, 12 (1), 678–685. https://doi.org/10.1021/ACSAMI.9B17786. Krauskopf, T.; Hartmann, H.; Zeier, W. G.; Janek, J. Toward a Fundamental Understanding of the Lithium Metal Anode in Solid-State Batteries - An Electrochemo-Mechanical Study on the Garnet-Type Solid Electrolyte Li 6.25 Al 0.25 La 3 Zr 2 O 12. ACS Appl Mater Interfaces 2019, 11 (15), 14463–14477. https://doi.org/10.1021/ACSAMI.9B02537/SUPPL_FILE/AM9B02537_SI_001.PDF.
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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.
Abstract:
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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Shin, Sunghwan, Francesco Greco, Florian Maier, and Hans-Peter Steinrück. "Enrichment effects of ionic liquid mixtures at polarized electrode interfaces monitored by potential screening." Physical Chemistry Chemical Physics 23, no. 18 (2021): 10756–62. http://dx.doi.org/10.1039/d0cp04811a.
Abstract:
The interface of electrodes and IL mixtures has been studied by in situ XPS. We found that the concentration of counterions at the interface can strongly deviate from the bulk composition due to interactions between electrode and IL.
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Le, Jia-Bo, Qi-Yuan Fan, Jie-Qiong Li, and Jun Cheng. "Molecular origin of negative component of Helmholtz capacitance at electrified Pt(111)/water interface." Science Advances 6, no. 41 (October 2020): eabb1219. http://dx.doi.org/10.1126/sciadv.abb1219.
Abstract:
Electrified solid/liquid interfaces are the key to many physicochemical processes in a myriad of areas including electrochemistry and colloid science. With tremendous efforts devoted to this topic, it is unexpected that molecular-level understanding of electric double layers is still lacking. Particularly, it is perplexing why compact Helmholtz layers often show bell-shaped differential capacitances on metal electrodes, as this would suggest a negative capacitance in some layer of interface water. Here, we report state-of-the-art ab initio molecular dynamics simulations of electrified Pt(111)/water interfaces, aiming at unraveling the structure and capacitive behavior of interface water. Our calculation reproduces the bell-shaped differential Helmholtz capacitance and shows that the interface water follows the Frumkin adsorption isotherm when varying the electrode potential, leading to a peculiar negative capacitive response. Our work provides valuable insight into the structure and capacitance of interface water, which can help understand important processes in electrocatalysis and energy storage in supercapacitors.
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Frankenberger, Martin, Madhav Singh, Alexander Dinter, and Karl-Heinz Pettinger. "EIS Study on the Electrode-Separator Interface Lamination." Batteries 5, no. 4 (November 17, 2019): 71. http://dx.doi.org/10.3390/batteries5040071.
Abstract:
This paper presents a comprehensive study of the influences of lamination at both electrode-separator interfaces of lithium-ion batteries consisting of LiNi1/3Mn1/3Co1/3O2 cathodes and graphite anodes. Typically, electrode-separator lamination shows a reduced capacity fade at fast-charging cycles. To study this behavior in detail, the anode and cathode were laminated separately to the separator and compared to the fully laminated and non-laminated state in single-cell format. The impedance of the cells was measured at different states of charge and during the cycling test up to 1500 fast-charging cycles. Lamination on the cathode interface clearly shows an initial decrease in the surface resistance with no correlation to aging effects along cycling, while lamination on both electrode-separator interfaces reduces the growth of the surface resistance along cycling. Lamination only on the anode-separator interface shows up to be sufficient to maintain the enhanced fast-charging capability for 1500 cycles, what we prove to arise from a significant reduction in growth of the solid electrolyte interface.
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Turak, Ayse. "On the Role of LiF in Organic Optoelectronics." Electronic Materials 2, no. 2 (June 3, 2021): 198–221. http://dx.doi.org/10.3390/electronicmat2020016.
Abstract:
Organic optoelectronic device behaviour is heavily dependent on interfacial effects due to the device architecture and thickness. Interfaces between the inorganic electrodes and the active organic layers play a defining role in the all of the electronic and stability processes that occur in organic light emitting diodes (OLEDs) and organic solar cells (OPVs). Amongst the many interlayers introduced at these interfaces to improve charge carrier movement and stability, LiF has proven to be the most successful and it is almost ubiquitous in all organic semiconductor devices. Implemented at both top and bottom contact interfaces, doped into the charge transporting layers, and used as encapsulants, LiF has played major roles in device performance and lifetime. This review highlights the use of LiF at both top and bottom contacts in organic optoelectronics, discusses the various mechanisms proposed for the utility of LiF at each interface, and explores its impact on device lifetimes. From examples relating to charge carrier flow, interfacial electronic level modification, and interfacial stability, a comprehensive picture of the role of LiF in organic devices can be formed. This review begins with a brief overview of the role of the interface in OLEDs and OPVs, and the general properties of LiF. Then, it discusses the implementation of LiF at the top contact electrode interface, followed by the bottom substrate contact electrode, examining both performance and degradation effects in both cases.
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Asayesh, Amirreza, Elina Ilen, Marjo Metsäranta, and Sampsa Vanhatalo. "Developing Disposable EEG Cap for Infant Recordings at the Neonatal Intensive Care Unit." Sensors 22, no. 20 (October 16, 2022): 7869. http://dx.doi.org/10.3390/s22207869.
Abstract:
Long-term EEG monitoring in neonatal intensive care units (NICU) is challenged with finding solutions for setting up and maintaining a sufficient recording quality with limited technical experience. The current study evaluates different solutions for the skin–electrode interface and develops a disposable EEG cap for newborn infants. Several alternative materials for the skin–electrode interface were compared to the conventional gel and paste: conductive textiles (textured and woven), conductive Velcro, sponge, super absorbent hydrogel (SAH), and hydro fiber sheets (HF). The comparisons included the assessment of dehydration and recordings of signal quality (skin interphase impedance and powerline (50 Hz) noise) for selected materials. The test recordings were performed using snap electrodes integrated into a forearm sleeve or a forehead band along with skin–electrode interfaces to mimic an EEG cap with the aim of long-term biosignal recording on unprepared skin. In the hydration test, conductive textiles and Velcro performed poorly. While the SAH and HF remained sufficiently hydrated for over 24 h in an incubator-mimicking environment, the sponge material was dehydrated during the first 12 h. Additionally, the SAH was found to have a fragile structure and was electrically prone to artifacts after 12 h. In the electrical impedance and recording comparisons of muscle activity, the results for thick-layer HF were comparable to the conventional gel on unprepared skin. Moreover, the mechanical instability measured by 1–2 Hz and 1–20 Hz normalized relative power spectrum density was comparable with clinical EEG recordings using subdermal electrodes. The results together suggest that thick-layer HF at the skin–electrode interface is an effective candidate for a preparation-free, long-term recording, with many advantages, such as long-lasting recording quality, easy use, and compatibility with sensitive infant skin contact.
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Mukhan, Orynbassar, Ji-Su Yun, and Sung-soo Kim. "Investigation of Interfacial Behavior of Ni-Rich NCM Cathode Particles in Sulfide-Based Solid-State Electrolyte." ECS Meeting Abstracts MA2023-02, no. 60 (December 22, 2023): 2892. http://dx.doi.org/10.1149/ma2023-02602892mtgabs.
Abstract:
All-solid-state batteries (ASSBs) are currently investigated as a future battery technology with conventional layered cathode materials because they can offer benefits in the gravimetric and volumetric energy densities compared to flammable liquid electrolyte lithium-ion batteries with graphite intercalation anode. The solid electrolyte is believed to suppress dendritic growth and low Coulombic efficiency on the lithium metal anode side, which are the key issues for the use of a lithium metal electrode in conventional batteries with liquid electrolyte. Moreover, layered transition metal oxides such as LiNixCoyMnzO2 (NCM, 0 < x, y, z < 1) are one of the most promising positive electrode active material candidates being developed to increase the energy density. In particular, recent studies have shown a tendency to decrease the cobalt content and increase the nickel content to increase energy density and price competitiveness, so high-nickel NCM can be the optimal material suitable for this purpose. However, the remaining interfacial challenges of the cathode / solid electrolyte interface still need to be solved. Herein, we investigated the kinetics such as charge transfer resistance at the interface between high nickel (Ni0.94) NCM particles and argyrodite (Li6PS5Cl) solid electrolytes using the microcavity electrode with the negative and positive pulsed current measurement technique and compared with liquid electrolytes using the same manner measurement technique. The cavity-electrode system is adopted to analyze the electrochemical properties of active particles and electrolytes confined in the cavity to exclude the effects of surrounding interfaces, barriers, and side reactions caused by battery components around the electrodes and the impact of loading and current collectors of the composite electrode. Therefore, understanding the electrode-electrolyte interface between cathode active particles and solid electrolytes is crucial for theoretical studies on the interfacial phenomenon in solid electrolyte batteries.
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Mian, Shan Yasin, Jonathan Roy Honey, Alejandro Carnicer-Lombarte, and Damiano Giuseppe Barone. "Large Animal Studies to Reduce the Foreign Body Reaction in Brain–Computer Interfaces: A Systematic Review." Biosensors 11, no. 8 (August 16, 2021): 275. http://dx.doi.org/10.3390/bios11080275.
Abstract:
Brain–computer interfaces (BCI) are reliant on the interface between electrodes and neurons to function. The foreign body reaction (FBR) that occurs in response to electrodes in the brain alters this interface and may pollute detected signals, ultimately impeding BCI function. The size of the FBR is influenced by several key factors explored in this review; namely, (a) the size of the animal tested, (b) anatomical location of the BCI, (c) the electrode morphology and coating, (d) the mechanics of electrode insertion, and (e) pharmacological modification (e.g., drug eluting electrodes). Trialing methods to reduce FBR in vivo, particularly in large models, is important to enable further translation in humans, and we systematically reviewed the literature to this effect. The OVID, MEDLINE, EMBASE, SCOPUS and Scholar databases were searched. Compiled results were analysed qualitatively. Out of 8388 yielded articles, 13 were included for analysis, with most excluded studies experimenting on murine models. Cats, rabbits, and a variety of breeds of minipig/marmoset were trialed. On average, over 30% reduction in inflammatory cells of FBR on post mortem histology was noted across intervention groups. Similar strategies to those used in rodent models, including tip modification and flexible and sinusoidal electrode configurations, all produced good effects in histology; however, a notable absence of trials examining the effect on BCI end-function was noted. Future studies should assess whether the reduction in FBR correlates to an improvement in the functional effect of the intended BCI.