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1
Şahin, Mustafa Ergin. "An Overview of Different Water Electrolyzer Types for Hydrogen Production". Energies 17, n. 19 (2 ottobre 2024): 4944. http://dx.doi.org/10.3390/en17194944.
Testo completoAbstract (sommario):
While fossil fuels continue to be used and to increase air pollution across the world, hydrogen gas has been proposed as an alternative energy source and a carrier for the future by scientists. Water electrolysis is a renewable and sustainable chemical energy production method among other hydrogen production methods. Hydrogen production via water electrolysis is a popular and expensive method that meets the high energy requirements of most industrial electrolyzers. Scientists are investigating how to reduce the price of water electrolytes with different methods and materials. The electrolysis structure, equations and thermodynamics are first explored in this paper. Water electrolysis systems are mainly classified as high- and low-temperature electrolysis systems. Alkaline, PEM-type and solid oxide electrolyzers are well known today. These electrolyzer materials for electrode types, electrolyte solutions and membrane systems are investigated in this research. This research aims to shed light on the water electrolysis process and materials developments.
2
Jansonius, Ryan, Marta Moreno e Benjamin Britton. "High Performance AEM Water Electrolysis with Aemion® Membranes". ECS Meeting Abstracts MA2022-01, n. 39 (7 luglio 2022): 1723. http://dx.doi.org/10.1149/ma2022-01391723mtgabs.
Testo completoAbstract (sommario):
By 2030 up to 50% of energy is expected to be carried in the bonds of H2. Global electrolysis capacity must increase from the current 240 MW to an anticipated 300 GW in 2030 and 3500 GW in 2050 to enable this transition. Alkaline and PEM electrolyzers are commercially mature with the currently market share of new installations roughly an equal split between these technologies. However, each of these electrolyzers are associated with challenges – alkaline electrolyzers operate at low current density, and require high concentration electrolytes (30 wt% KOH) to conduct hydroxides through the porous electrode separator (I.e., Zirfon). PEM electrolyzers use a proton conductive membrane to enable high current densities, however, running the reaction in acidic electrolyte requires platinum group catalysts and component coatings that hinder scalability at 2050 targets. AEM water electrolyzers address both of these challenges by pairing anion exchange membrane with alkaline electrolyte to enable high current density operation, at high pressure, without noble metal catalysts. These attributes enable the most cost-effective green hydrogen - bringing the DOE hydrogen shot target of $1/kg within reach. Anion exchange membrane chemistries have previously hindered this type of electrolyzer – AEMs based on quaternary amines, or pendant imidazolium groups chemically degrade in concentrated alkaline electrolyte, and mechanically degrade (from swelling) in low concentration alkaline media. Ionomr’s Aemion+ membranes are based on a sterically-protected polybenzimidazole chemistry and are chemically robust (stable in up to 10 M KOH), and exhibit low swelling to enable operation in low concentration electrolytes. These membranes are an enabling technology for long duration water and CO2 electrolysis. This talk highlights how Ionomr’s Aemion+ membranes enable performance in excess of 1 A/cm2 at 1.8 V with non-PGM catalysts and a variety of configurations, and >4000 hours of durability in continuous operation. Figure 1
3
Kee, Robert J., Huayang Zhu, Sandrine Ricote e Greg Jackson. "(Invited) Mixed Conduction in Ceramic Electrolytes For Intermediate-Temperature Fuel Cells and Electrolyzers". ECS Meeting Abstracts MA2023-02, n. 46 (22 dicembre 2023): 2216. http://dx.doi.org/10.1149/ma2023-02462216mtgabs.
Testo completoAbstract (sommario):
High-temperature fuel cells and electrolyzers (e.g., T > 700 ˚C) rely on oxide electrolytes such as stabilized cubic zirconia that conduct a single defect, oxygen vacancies. Intermediate-temperature electrochemical cells (e.g., T < 650 ˚C) utilize mixed conducting ceramic electrolytes, that conduct multiple defects. Operating at T < 600 ˚C facilitates lower-cost interconnect materials and balance-of-plant components, but the mixed conductor behavior can reduce fuel cell voltages and lower electrolyzer faradaic efficiencies. Predicting behavior of these mixed conductors, even at open-circuit voltage, requires modeling the coupled transport of the multiple conducting defects in the electrolyte. Detailed models of mixed conductors coupled to porous electrode models can simulate cell performance over a broad range of operating conditions. This presentation highlights models of two types of cells with mixed conducting oxide electrolytes. Firstly, gadolinium-doped ceria (GDC) primarily conducts oxygen vacancies but also some electrons via a reduced-ceria small polaron, but it performs well in intermediate temperature solid-oxide fuel cells [1]. Secondly, yttrium-doped barium zirconates (BZY) primarily conducts protons but also oxygen vacancies and small polarons, which contribute to electronic leakage. Variants of BZY electrolytes perform well in fuel cells and electrolyzers [2-4]. This paper focuses on cell-level models of these mixed-conductors and how to identify favorable regions for high performance in fuel cells and electrolyzers. Zhu, A. Ashar, R.J. Kee, R.J. Braun, G.S. Jackson, “Physics-based model to represent the membrane-electrode assemblies of solid-oxide fuel cells based on gadolinium-doped ceria,” J. Electrochem. Soc., Under revision, 2023. J. Kee, S. Ricote, H. Zhu, R.J. Braun, G. Carins, J.E. Persky, “Perspectives on technical challenges and scaling considerations for tubular protonic-ceramic electrolysis cells and stacks ,” J. Electrochem. Soc. 169:054525 (2022). Zhu, Y. Shin, S. Ricote, R.J. Kee, “Defect incorporation and transport in dense BaZr0.8Y0.2O3-d membranes and their impact on hydrogen separation and compression,” J. Electrochem. Soc., Under revision, 2023. Zhu, S. Ricote, R.J. Kee, “Thermodynamics, transport, and electrochemistry in proton-conducting ceramic electrolysis cells,” in High Temperature Electrolysis, W. Sitte and R. Merkle, Editors, IOP Publishing, 2023.
4
Aquigeh, Ivan Newen, Merlin Zacharie Ayissi e Dieudonné Bitondo. "Multiphysical Models for Hydrogen Production Using NaOH and Stainless Steel Electrodes in Alkaline Electrolysis Cell". Journal of Combustion 2021 (19 marzo 2021): 1–11. http://dx.doi.org/10.1155/2021/6673494.
Testo completoAbstract (sommario):
The cell voltage in alkaline water electrolysis cells remains high despite the fact that water electrolysis is a cleaner and simpler method of hydrogen production. A multiphysical model for the cell voltage of a single cell electrolyzer was realized based on a combination of current-voltage models, simulation of electrolyzers in intermittent operation (SIMELINT), existing experimental data, and data from the experiment conducted in the course of this work. The equipment used NaOH as supporting electrolyte and stainless steel as electrodes. Different electrolyte concentrations, interelectrode gaps, and electrolyte types were applied and the cell voltages recorded. Concentrations of 60 wt% NaOH produced lowest range of cell voltage (1.15–2.67 V); an interelectrode gap of 0.5 cm also presented the lowest cell voltage (1.14–2.71 V). The distilled water from air conditioning led to a minimum cell voltage (1.18–2.78 V). The water from a factory presented the highest flow rate (12.48 × 10−1cm3/min). It was found that the cell voltage of the alkaline electrolyzer was reduced considerably by reducing the interelectrode gap to 0.5 cm and using electrolytes that produce less bubbles. A maximum error of 1.5% was found between the mathematical model and experimental model, indicating that the model is reliable.
5
Gerhardt, Michael Robert, Alejandro O. Barnett, Thulile Khoza, Patrick Fortin, Sara Andrenacci, Alaa Y. Faid, Pål Emil England Karstensen, Svein Sunde e Simon Clark. "An Open-Source Continuum Model for Anion-Exchange Membrane Water Electrolysis". ECS Meeting Abstracts MA2023-01, n. 36 (28 agosto 2023): 2002. http://dx.doi.org/10.1149/ma2023-01362002mtgabs.
Testo completoAbstract (sommario):
Anion-exchange membrane (AEM) electrolysis has the potential to produce green hydrogen at low cost by combining the advantages of conventional alkaline electrolysis and proton-exchange membrane electrolysis. The alkaline environment in AEM electrolysis enables the use of less expensive catalysts such as nickel, whereas the use of a solid polymer electrolyte enables differential pressure operation. Recent advancements in AEM performance and lifetime have spurred interest in AEM electrolysis, but many open research areas remain, such as understanding the impacts of water transport in the membrane and salt content in the electrolyte on cell performance and degradation. Furthermore, integrating electrolyser systems into renewable energy grids necessitates dynamic operation of the electrolyser cell, which introduces additional challenges. Computational modelling of AEM electrolysis is ideally suited to tackle many of these open questions by providing insight into the transport processes and electrochemical reactions occurring in the cell under dynamic conditions. In this work, an open-source, transient continuum modelling framework for anion-exchange membrane (AEM) electrolysis is presented and applied to study electrolyzer cell dynamic performance. The one-dimensional cell model contains coupled equations for multiphase flow in the porous transport layers, a parameterized solution property model for potassium hydroxide electrolytes, and coupled ion and water transport equations to account for water activity gradients within the AEM. The model is validated with experimental results from an AEM electrolyser cell. We find that pH gradients develop within the electrolyte due to the production and consumption of hydroxide, which can lead to voltage losses and cell degradation. The influence of these pH gradients on potential catalyst dissolution mechanisms is explored and discussed. Finally, initial studies of transient operation will be presented. This work has been performed in the frame of the CHANNEL project. This project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under grant agreement No 875088. This Joint undertaking receives support from the European Union's Horizon 2020 Research and Innovation program, Hydrogen Europe and Hydrogen Europe Research. Some of this work has been performed within the MODELYS project "Electrolyzer 2030 – Cell and stack designs" financially supported by the Research Council of Norway under project number 326809.
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Ovechenko, Dmitry, e Alexander Boychenko. "Transformation of the Nanoporous Structure of Anodic Aluminium Oxide and its “Nonelectrolysis” Electroluminescence". Solid State Phenomena 312 (novembre 2020): 166–71. http://dx.doi.org/10.4028/www.scientific.net/ssp.312.166.
Testo completoAbstract (sommario):
On a film of aluminum oxide (Al2O3) formed by electrolytic oxidation in distilled water (DW), the growth, transformation of its nanoporous structure, and the generation of electroluminescence (EL) in ketones and related compounds containing carbonyl groups were studied. For those contributing to the brightest EL – acetylacetone and methylpyrrolidone, it was found that the processes described in these electrolytes proceed with the highest intensity. Under the same electrolytes and conditions, similar processes, but with a lower intensity, proceed for A2O3 formed on pure aluminum. It was found that, with the external voltage, thermodynamic and geometrical parameters of the electrolytic system being constant, the brightness characteristics of the EL of the anodic Al2O3 are influenced by its structural organization and the electrophysical characteristics of the electrolyte surrounding the oxide film, which is proposed to be arbitrarily called “nonelectrolysis” because electrolysis products are not revealed in it.
7
Ashraf, Juveiriah M., Myriam Ghodhbane e Chiara Busa. "The Effect of Ionic Carriers and Degree of Solidification on the Solid-State Electrolyte Performance for Free-Standing Carbon Nanotube Supercapacitor". ECS Meeting Abstracts MA2022-02, n. 7 (9 ottobre 2022): 2490. http://dx.doi.org/10.1149/ma2022-0272490mtgabs.
Testo completoAbstract (sommario):
To eliminate electrolyte leakage, the development of safe and flexible supercapacitors necessitates solid-state electrolytes which integrate both high mechanical and electrochemical capabilities. Quasi-solid-state electrolytes, which constitute a polymer matrix along with an aqueous electrolytic phase, are a viable answer to this problem. Recently, gel electrolytes have gained a lot of attention in flexible and wearable electronic devices due to their remarkable advancements. However, the limitation in the multi-functional abilities and high-performance in such gels hinders the practical usage of such devices. On the electrochemical perspective, the performance of the gel electrolyte depends on the type of ionic carrier (acidic, alkaline, or salt-based), size of the ion, solvent concentration, type of polymer, as well as the interaction between the polymer and other components. Moreover, the performance of the electrolyte differs with the electrode-electrolyte interface and thus is highly dependent on the electrode material. For this reason, it is vital to carry a parametric study to evaluate the effect of the above stated. The aim of this study is to investigate the effect of changing the ionic carrier (namely H3PO4, KOH and LiCl) as well as the solvent concentration on architecturally engineered PVA-based electrolytes’ performance in free-standing CNT supercapacitor using a bio-based compound, cellulose as a binder. The dependence of the electrolyte’s mechanical structure for long term stability is further evaluated by using the optimized concentration of each (H3PO4, KOH and LiCl) by freezing and de-freezing the gel to form membrane-like films, as a result of the increased physical cross-linking. The supercapacitors are studied for their capacitance, charge/discharge capabilities as well their long-term stability and also compared with aqueous electrolyte for the three aforementioned ionic carriers.
8
Kumar Gupta, Pankaj, Akshay Dvivedi e Pradeep Kumar. "Effect of Electrolytes on Quality Characteristics of Glass during ECDM". Key Engineering Materials 658 (luglio 2015): 141–45. http://dx.doi.org/10.4028/www.scientific.net/kem.658.141.
Testo completoAbstract (sommario):
Electrochemical discharge machining (ECDM) is an ideal process for machining of nonconductive materials in micro-domain. The material removal takes place due to combined action of localised sparks and electrolysis in an electrolytic chamber. The electrolyte is most important process parameter for ECDM as it governs spark action as well as electrolysis. This article presents a comparison of three preferred electrolytes used in ECDM viz. NaCl, KOH and NaOH on drilling of glass workpiece material. The quality characteristics measured are material removal rate (MRR) and hole overcut. Results reveal that NaOH provides 9.7 and 3.8 times higher MRR than NaCl and KOH respectively. MRR and hole overcut are found significantly affected by spark characteristics.
9
Li, Pengsong, Shiyuan Wang, Imran Ahmed Samo, Xingheng Zhang, Zhaolei Wang, Cheng Wang, Yang Li et al. "Common-Ion Effect Triggered Highly Sustained Seawater Electrolysis with Additional NaCl Production". Research 2020 (24 settembre 2020): 1–9. http://dx.doi.org/10.34133/2020/2872141.
Testo completoAbstract (sommario):
Developing efficient seawater-electrolysis system for mass production of hydrogen is highly desirable due to the abundance of seawater. However, continuous electrolysis with seawater feeding boosts the concentration of sodium chloride in the electrolyzer, leading to severe electrode corrosion and chlorine evolution. Herein, the common-ion effect was utilized into the electrolyzer to depress the solubility of NaCl. Specifically, utilization of 6 M NaOH halved the solubility of NaCl in the electrolyte, affording efficient, durable, and sustained seawater electrolysis in NaCl-saturated electrolytes with triple production of H2, O2, and crystalline NaCl. Ternary NiCoFe phosphide was employed as a bifunctional anode and cathode in simulative and Ca/Mg-free seawater-electrolysis systems, which could stably work under 500 mA/cm2 for over 100 h. We attribute the high stability to the increased Na+ concentration, which reduces the concentration of dissolved Cl- in the electrolyte according to the common-ion effect, resulting in crystallization of NaCl, eliminated anode corrosion, and chlorine oxidation during continuous supplementation of Ca/Mg-free seawater to the electrolysis system.
10
Prokhorov, Konstantin, Alexander Burdonov e Peter Henning. "Study of flow regimes and gas holdup in a different potentials medium in an aerated column". E3S Web of Conferences 192 (2020): 02013. http://dx.doi.org/10.1051/e3sconf/202019202013.
Testo completoAbstract (sommario):
A generation of hydrogen and oxygen bubbles by of aqueous solutions of electrolytes was carried out. Two electrolysis modifications was study: electrolysis without a membrane to production of oxygen and hydrogen and membrane electrolysis with separation of catholyte and anolyte. The influence of the model conditions of the experiment such as electrolyte pH, concentration, and current density and the distribution of bubble sizes and gas holdup in the column are discussed. An inverse dependence of the hydrogen bubbles diameter in the catholyte medium on the current density and a direct dependence on the concentration of electrolytes are experimentally investigated. The oxygen bubbles tend to become larger with increasing current density and electrolyte concentration in anolyte medium. In electrolysis without a membrane, bubbles become smaller with increasing current density and decreasing the electrolyte concentration.
11
Krasnova, E. V., Yu A. Morgunov, B. P. Saushkin, I. A. Slyusar e S. A. Smeyan. "Effect of Aqueous Electrolyte Composition on Efficiency of Electrochemical Post-Processing of Additive Manufacturing Products from Ti-6Al-4V Alloy Obtained by Selective Electron Beam Melting". Elektronnaya Obrabotka Materialov 60, n. 5 (ottobre 2024): 1–12. http://dx.doi.org/10.52577/eom.2024.60.5.01.
Testo completoAbstract (sommario):
The influence of the anionic composition of an aqueous electrolyte on the efficiency of the electrochemical leveling of the initial microgeometry of samples obtained by the selective electron beam melting (SEBM) at the following mode parameters was studied: current density – 20 A/cm2, initial interelectrode gap – 0.3 mm, average speed of electrolyte pumping – 12 m/c. Aqueous solutions of sodium chloride, nitrate, perchlorate and bisalt electrolytes based on them were studied. It was that aqueous solutions of sodium perchlorate have the best microleveling properties among the studied working media, which provides the ability to reduce the parameters Ra and Rz from values of 35 and 180 μm, respectively, to values of 3.2 and 20 μm during electrolysis of 30 s in a direct-flow electrolyzer. It was established that the microgeometry leveling corresponds to the model of the secondary distribution of dissolution rates; two main factors were identified that significantly influenced on the result: polarization of the electrodes and a decrease in the oxidation state of metal ions passing into the solution during electrochemical machining in the vicinity of the depression in relation to the protrusion due to changes in the local conditions of electrolysis. Microetching along grain boundaries in the studied electrolytes was not detected at the accepted parameters of the electrolysis mode.
12
Mirzoyeva, Amina A., e Ikhtiyar B. Bakhtiyarli. "ELECTROLYTIC SEPARATION OF SELENIUM FROM LEAD ADMIXTURES". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, n. 3 (13 aprile 2017): 67. http://dx.doi.org/10.6060/tcct.2017603.5436.
Testo completoAbstract (sommario):
In this article the electrochemical methods were developed for selenium separation from the lead admixtures in technical selenium which was obtained at the refining the anodic muds from Shchelkovo combinate at the use of nitro-acidic and sulfur-acidic electrolytes. At the optimal conditions of carrying out the electrolysis under using nitrogen acidic electrolytes almost all lead is precipitated on the anode and, accordingly, it is separated from selenium. Later, after separation of the main mass of lead, the precipitation of selenium on the cathode was carried out. According to technology proposed the electrolytic selenium of high purity degree (99.999%) was obtained at application of nitric solutions of electrolyte. The content of lead in the complex cathode-selenium was 1·10-4%. Under the optimal conditions of selenium precipitation from the hydrochloric acidic electrolytes, selenium was not found in the cathode sediments of lead. The admixtures of different elements (Te, Pb, Bi, Ag, Si and others) existing in technical selenium make worse its electrophysical properties very strongly. In order to obtain selenium with a high degree of purity, it is necessary to carry out the wide scientific investigations in the field of electrolytic purification of technical selenium.Forcitation:Mirzoyeva A.A., Bakhtiyarli I.B. Electrolytic separation of selenium from lead admixtures. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 3. P. 67-71.
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Park, Habin, Hui Min Tee, Parin Shah, Chandler Dietrich e Paul Kohl. "Durability and Performance of Poly(norbornene) Membranes and Ionomers in Alkaline Electrolyzers". ECS Meeting Abstracts MA2023-01, n. 36 (28 agosto 2023): 2029. http://dx.doi.org/10.1149/ma2023-01362029mtgabs.
Testo completoAbstract (sommario):
Ion conducting polymer electrolytes provide an enabling technology for low-temperature alkaline electrolyzers. The critical parameters of solid polymer electrolytes include ionic conductivity, ion selectivity, chemical resistance and dimensional stability in the presence of excess water. High pH operation using anion conductive polymer electrolytes has several potential advantages over acid-based polymer devices including low-cost catalysts, hydrocarbon (non-perfluorinated) polymer, and low cost cell components. In this study, a family of hydroxide conducting, poly(norbornene) solid polymer electrolytes were synthesized and used in high-performance, durable membrane electrode assemblies for fuel cells and electrolyzers. In addition to membranes, covalently bonded, self-adherent, hydroxide conducting ionomers were used to form high-performance, durable membrane electrode assembly for water electrolysis. The self-adhesive ionomers and membranes are based on hydroxide conducting poly(norbornene) polymers. The effect of porous transport layer material and porosity was examined. High performance electrolysis with very low degradation rates was achieved using stainless steel and nickel porous transport layers and flow-channels
14
Abellán, Gonzalo, Vicent Lloret e Alvaro Seijas Da Silva. "(Invited) Accelerated Three Electrode Cell (TEC) Testing for Optimizing Electrodes in Conventional Alkaline Electrolysis and Anion Exchange Membrane Water Electrolysis". ECS Meeting Abstracts MA2024-01, n. 28 (9 agosto 2024): 1486. http://dx.doi.org/10.1149/ma2024-01281486mtgabs.
Testo completoAbstract (sommario):
The merging of conventional Alkaline Electrolysis (AEL) and Proton Exchange Membrane Water Electrolysis (PEMWE) has led to the development of Anion Exchange Membrane Water Electrolysis (AEMWE). At this juncture, both AEL and AEMWE technologies offer an advantage over PEMWE as they do not require critical raw components and materials (CRM).[1] While AEMWE has demonstrated higher efficiencies than AEL with thin membranes and low concentrations of KOH, AEL technology addresses the significant stability challenge posed by anionic membranes by employing KOH electrolyte with novel zero-gap configurations, relying on stable diaphragms. Consequently, AEL technology offers a more cost-effective and scalable solution for current large-scale hydrogen production, while AEMWE remains a promising solution that will most probably be implemented on larger scales in the following decade. In any case, both technologies require more efficient and scalable catalysts for lowering the overall cell voltage of electrolyzers. Along this front, Matteco’s patented processes stand at the forefront of manufacturing highly active and stable catalysts and electrodes crafted from Layered Double Hydroxides (LDHs), which have gained increasing attention due to their low overpotentials and promising stabilities.[2] However, Beyond the intrinsic qualities of the catalysts, a myriad of factors —electrolyte concentration, substrate type, and the catalyst/substrate interface— play pivotal roles in determining electrolyzer activity and stability, forming a complex multiparameter matrix that will condition the final performance of the electrolysers. Contrary to three-electrode catalyst testing conditions for PEMWE, in which acids are used to simulate the real conditions of electrolyzers, AEL- and AEMWE-TEC testing can be performed using realistic conditions, from 0.1 to 7M alkaline electrolytes. Thus, this work presents the results of Matteco’s accelerated TEC testing to decipher the complex multiparameter alkaline electrolysis matrix, obtaining the most promising catalysts, substrates, and processes that deliver the best performances and stabilities of AEL and AEMWE technologies. References: [1] N. Du, C. Roy, R. Peach, M. Turnbull, S. Thiele and C. Bock, Chemical Reviews, 122, 11830 (2022). [2] L. Hager, M. Hegelheimer, J. Stonawski, A. T. S. Freiberg, C. Jaramillo-Hernández, G. Abellán, A. Hutzler, T. Böhm, S. Thiele and J. Kerres, Journal of Materials Chemistry A, 11, 22347 (2023).
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Rudenko, A. V., A. A. Kataev, O. Yu Tkacheva, Yu P. Zaykov, A. A. Pyanykh e G. V. Arkhipov. "Viscosity of conventional cryolite-alumina melts". Izvestiya Vuzov. Tsvetnaya Metallurgiya (Universities' Proceedings Non-Ferrous Metallurgy) 27, n. 6 (10 dicembre 2021): 4–11. http://dx.doi.org/10.17073/0021-3438-2021-6-4-11.
Testo completoAbstract (sommario):
The study covers the viscosity of NaF–AlF3–CaF2–Al2O3 conventional cryolite-alumina melts with a cryolite ratio CR = 2.3 depending on the CaF2, Al2O3 content and temperature. The viscosity of cryolite-alumina electrolyte samples prepared under laboratory conditions and electrolyte samples of industrial electrolytic cells was measured by the rotary method using the FRS 1600 rheometer («Anton Paar», Austria). The laminar flow region of the melt determined according to the dependence of viscosity on shear rate at a constant temperature was 10–15 s–1 for all the studied samples. The temperature dependence of cryolite-alumina melt viscosity was measured at a shear rate of 12 ± 1 s–1 in the temperature range from liquidus to 1020 °C. It was shown that the change in the viscosity of all samples in the investigated temperature range (50–80 °С) can be described by a linear equation. The average temperature coefficient of linear equations describing the viscosity of cryolite-alumina electrolytes prepared in laboratory conditions was 0.005 mPа· s/°С, which is 2 times less compared to industrial cell electrolytes. Thus, the change in the viscosity of industrial cell electrolytes with increasing temperature is more significant. Both alumina and calcium fluoride additives increase the cryolite melt viscosity. The viscosity of samples prepared with the conventional composition NaF–AlF3–5%CaF2–4%Al2O3 (CR = 2.3) is equal to 3.11 ± 0.04 mPа· s at an electrolysis operating temperature of 960 °C, while the viscosity of industrial cell electrolytes with the same cryolite ratio is 10–15 % higher and falls in the range of 3.0–3.7 mPа· s depending on the electrolyte composition.
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Chen, H. L., e Y. X. Zhang. "Eco-friendly oxalic acid and citric acid mixed electrolytes using for plasma electrolytic polishing 304 stainless steel". Journal of Physics: Conference Series 2345, n. 1 (1 settembre 2022): 012029. http://dx.doi.org/10.1088/1742-6596/2345/1/012029.
Testo completoAbstract (sommario):
Abstract The traditional of mixed electrolyte of H2SO4 and H3PO4 widely used in electropolishing 304 stainless steel. Due to environmental protection and safety issues, there is an urgent need to develop more environmentally friendly electrolytes. In this study, 304 stainless steel was electropolished by plasma electropolishing using a mixed electrolyte of oxalic acid and citric acid, which are environmentally friendly electrolytes. The mixed electrolyte concentration of oxalic acid and citric acid were 0.01 M, 0.05M, 0.1M, 0.3M and 0.5 M, respectively. The volume mixing percentage is adjusted to about 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8, respectively. Plasma power is about 1.3 kW, electrolysis time is 5 and 1 minutes, respectively. The results show that low-concentration mixed electrolyte, shortened electrolysis time and proper electrolyte mixing ratio, can obtain better surface roughness. The mixing ratio of oxalic acid and citric acid mixed electrolyte, and the factors that may affect the surface roughness of plasma electropolished 304 stainless steel, will be discussed in the text.
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Kohl, Paul, Mrinmay Mandal, Mengjie Chen, Habin Park e Parin Shah. "(Invited) Anion Conducting Solid Polymer Ionomers Electrolytes for Fuel Cells and Electrolyzers". ECS Meeting Abstracts MA2022-02, n. 46 (9 ottobre 2022): 1718. http://dx.doi.org/10.1149/ma2022-02461718mtgabs.
Testo completoAbstract (sommario):
Ion conducting polymer electrolytes provide an enabling technology for the creation of low temperature fuel cells, hydrogen producing water electrolyzers, and flow batteries. The critical parameters of solid polymer electrolytes include ionic conductivity, ion selectivity, chemical resistance and dimensional stability in the presence of excess water. High pH operation using anion conductive polymer electrolytes has several potential advantages over acid-based polymer devices including low-cost catalysts, hydrocarbon (non-perfluorinated) polymer, and low cost cell components. However, the identification and synthesis of stable, hydroxide conducting solid polymer electrolytes has been elusive. In this study, a family of hydroxide conducting, poly(norbornene) solid polymer electrolytes were synthesized and used in high-performance, durable membrane electrode assemblies for fuel cells and electrolyzers. In addition to membranes, covalently bonded, self-adherent, hydroxide conducting ionomers were used to form high-performance, durable membrane electrode assembly for water electrolysis. Electrodes made by grind-spray method were compared to electrodes prepared by the solvent-cast method. The self-adhesive ionomers and membranes are based on hydroxide conducting poly(norbornene) polymers. The effect of porous transport layer material and porosity was examined. High performance electrolysis with very low degradation rates was achieved using stainless steel and nickel porous transport layers.
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Rakhadilov, B. K., D. R. Baizhan, Zh B. Sagdoldina e K. Torebek. "Research of regimes of applying coats by the method of plasma electrolytic oxidation on Ti-6Al-4V". Bulletin of the Karaganda University. "Physics" Series 105, n. 1 (30 marzo 2022): 99–106. http://dx.doi.org/10.31489/2022ph1/99-106.
Testo completoAbstract (sommario):
In this work, ceramic coatings were formed on Ti6Al4V titanium alloy using a technique of plasma electrolytic oxidation. Plasma electrolytic oxidation was carried out in electrolytes with different chemical compositions and the effect of the electrolyte on the macro-and microstructure, pore size, phase composition and wear resistance of coatings was estimated. Three types of electrolytes based on sodium compounds were used, including phosphate, hydroxide, and silicate. The composition of the electrolyte affects the intensity and size of microcharges and the volume of gas release of various electrolytes. The plasma electrolytic oxidation processes were carried out at a fixed voltage (270 V) for 5 minutes. The results showed that the coating was mainly composed of rutile- and anatase TiO2 , but a homogeneous structure with lower porosity and a large number of crystalline anatase phases was obtained in the coating prepared in the silicate-based electrolyte. The diffractogram electrolytes did not reveal the peaks of the crystalline phases associated with the PO4 3— and SiO3 2— anions. This means that these anions included only oxygen in the coatings. The morphology and phase composition of the samples were studied using a scanning electron microscope and an X-ray diffractometer, respectively. Wear resistance was evaluated by the “ball-disc” method on the TRB3 tribometer. The wear resistance of various coatings formed on Ti6Al4V titanium alloys showed completely different wear resistance. The lowest coefficient of friction (µ = 0.3) was demonstrated by the coating obtained based on phosphate. This may be due to a large number of crystal phases of rutile. The sample prepared in a hydroxide-based electrolyte showed a high wear coefficient (µ=0.52). This effect can be obtained by eliminating surface defects (microcracks and micropores).
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Lee, Seokhee, Sang Won Lee, Suji Kim e Tae Ho Shin. "Recent Advances in High Temperature Electrolysis Cells using LaGaO3-based Electrolyte". Ceramist 24, n. 4 (31 dicembre 2021): 424–37. http://dx.doi.org/10.31613/ceramist.2021.24.4.06.
Testo completoAbstract (sommario):
High temperature electrolysis is a promising option for carbon-free hydrogen production and huge energy storage with high energy conversion efficiencies from renewable and nuclear resources. Over the past few decades, yttria-stabilized zirconia (YSZ) based ion conductor has been widely used as a solid electrolyte in solid oxide electrolysis cells (SOECs). However, its high operation temperature and lower conductivity in the appropriate temperature range for solid electrochemical devices were major drawbacks. Regarding improving ionic-conducting electrolytes, several groups have contributed significantly to developing and applying LaGaO3 based perovskite as a superior ionic conductor. La(Sr)Ga(Mg)O3 (LSGM) electrolyte was successfully validated for intermediate-temperature solid oxide fuel cells (SOFCs) but was rarely conducted on SOECs for its high efficient electrolysis performance. Their lower mechanical strengths or higher reactivity with electrode compared with the YSZ electrolysis cells, which make it difficult to choose compatible materials, remain major challenges. In this field, SOECs have attracted a great attention in the last few years, as they offer significant power and higher efficiencies compared to conventional YSZ based electrolysers. Herein, SOECs using LSGM based electrolyte, their applications, high performance, and their issues will be reviewed.
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Lee, Seokhee, Sang Won Lee, Suji Kim e Tae Ho Shin. "Recent Advances in High Temperature Electrolysis Cells using LaGaO3-based Electrolyte". Ceramist 24, n. 4 (31 dicembre 2021): 424–37. http://dx.doi.org/10.31613/ceramist.2021.24.4.42.
Testo completoAbstract (sommario):
High temperature electrolysis is a promising option for carbon-free hydrogen production and huge energy storage with high energy conversion efficiencies from renewable and nuclear resources. Over the past few decades, yttria-stabilized zirconia (YSZ) based ion conductor has been widely used as a solid electrolyte in solid oxide electrolysis cells (SOECs). However, its high operation temperature and lower conductivity in the appropriate temperature range for solid electrochemical devices were major drawbacks. Regarding improving ionic-conducting electrolytes, several groups have contributed significantly to developing and applying LaGaO3 based perovskite as a superior ionic conductor. La(Sr)Ga(Mg)O3 (LSGM) electrolyte was successfully validated for intermediate-temperature solid oxide fuel cells (SOFCs) but was rarely conducted on SOECs for its high efficient electrolysis performance. Their lower mechanical strengths or higher reactivity with electrode compared with the YSZ electrolysis cells, which make it difficult to choose compatible materials, remain major challenges. In this field, SOECs have attracted a great attention in the last few years, as they offer significant power and higher efficiencies compared to conventional YSZ based electrolysers. Herein, SOECs using LSGM based electrolyte, their applications, high performance, and their issues will be reviewed.
21
Park, Habin, Chenyu Li e Paul Kohl. "Durability and Performance of Poly(norbornene) Anion Exchange Membrane Alkaline Electrolyzer with High Ionic Strength Anolyte". ECS Meeting Abstracts MA2024-01, n. 34 (9 agosto 2024): 1792. http://dx.doi.org/10.1149/ma2024-01341792mtgabs.
Testo completoAbstract (sommario):
Anion exchange polymer electrolytes enable low-temperature alkaline water electrolysis for reliable green hydrogen production. Anion exchange membrane water electrolysis (AEMWE) with alkaline electrolytes has several advantages over the proton exchange membrane water electrolysis using acid-based polymer electrolytes. The advantages include low-cost catalysts, all hydrocarbon non-fluorinated polymer membrane, and low-cost cell components. Long-term durability of AEMWEs in high pH operation has been challenging, although there have been significant performance improvements. AEMWE operated at low hydroxide anolyte provides improved chemical stability. In this study, an understanding of the high ionic-strength anolyte is provided along with demonstration of the AEMWE performance and durability. Anion exchange poly(norbornene) solid polymer electrolytes show high-performance, durable membrane electrode assemblies for alkaline electrolysis. Covalently bonded, self-adhesive solid polymer ionomers were used in electrodes for durable electrolysis. Hydration problem with the low pH alkaline anolyte in dry-cathode AEMWE is presented. The effect of anolyte concentration and mobile cations on the cathode electrolysis performance using a low hydroxide anolyte was investigated. High ionic strength anolyte was prepared by changing the mobile cation concentration while maintaining a constant anolyte pH. The mechanism of cathode hydration improvement through use of a high ionic strength anolyte is presented. Long-term durability with the optimal high ionic strength electrolyte is discussed.
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Choi, Dongnyeok, e Kwon-Yeong Lee. "Experimental Study on Water Electrolysis Using Cellulose Nanofluid". Fluids 5, n. 4 (28 settembre 2020): 166. http://dx.doi.org/10.3390/fluids5040166.
Testo completoAbstract (sommario):
Hydrogen energy is considered to be a future energy source due to its higher energy density as compared to renewable energy and ease of storage and transport. Water electrolysis is one of the most basic methods for producing hydrogen. KOH and NaOH, which are currently used as electrolytes for water electrolysis, have strong alkalinity. So, it cause metal corrosion and can be serious damage when it is exposed to human body. Hence, experiments using cellulose nanofluid (CNF, C6H10O5) as an electrolyte were carried out to overcome the disadvantages of existing electrolytes and increase the efficiency of hydrogen production. The variables of the experiment were CNF concentration, anode material, voltage applied to the electrode, and initial temperature of the electrolyte. The conditions showing the optimal hydrogen production efficiency (99.4%) within the set variables range were found. CNF, which is not corrosive and has high safety, can be used for electrolysis for a long period of time because it does not coagulate and settle over a long period of time unlike other inorganic nanofluids. In addition, it shows high hydrogen production efficiency. So, it is expected to be used as a next-generation water electrolysis electrolyte.
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Gebremariam, Goitom K., Aleksandar Z. Jovanović e Igor A. Pašti. "Kinetics of Hydrogen Evolution Reaction on Monometallic Bulk Electrodes in Various Electrolytic Solutions". Catalysts 13, n. 10 (18 ottobre 2023): 1373. http://dx.doi.org/10.3390/catal13101373.
Testo completoAbstract (sommario):
The hydrogen evolution reaction (HER) holds pivotal significance in electrochemical energy conversion. In this study, we present essential HER kinetic parameters encompassing nine metals (Ag, Au, Co, Cr, Fe, Ni, Pt, W, and Zn) evaluated within seven distinct electrolytes (0.1 mol dm−3 HClO4, 0.1 mol dm−3 HCl, 0.5 mol dm−3 NaCl, 1 mol dm−3 KH2PO4, 0.1 mol dm−3 KOH, 0.1 mol dm−3 LiOH, and 1 mol dm−3 KOH). Through careful measures to restrain oxide formation, HER activity was measured on clean electrodes, while the assessment of HER activity on oxidatively treated metals was also performed. By correlating HER exchange current densities with calculated hydrogen binding energies, we show that the shape of HER volcano curves is largely preserved in studied electrolytes, at least around their apexes. Additionally, depending on the metal–electrolyte combination, the presence of surface oxide can have both positive and negative effects on HER kinetics. Finally, we collated HER kinetic data for bulk surfaces from diverse literature sources, offering a comprehensive overview of the kinetic parameters governing hydrogen evolution across distinct electrolytic environments. These insights have practical significance, guiding the development of new catalytic materials for different water electrolysis technologies, optimizing electrolyte formulations for boosting HER, and enhancing energy efficiency and catalytic performance through catalyst–electrolyte synergies.
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Kuzin, Ya S., I. A. Kozlov, S. V. Sibileva e M. A. Fomina. "INVESTIGATION OF THE INFLUENCE OF COMPONENT COMPOSITION OF PEO ELECTROLYTES ON THEIR STABILITY AND COATING PROPERTIES". Proceedings of VIAM, n. 11 (2020): 102–12. http://dx.doi.org/10.18577/2307-6046-2020-0-11-102-112.
Testo completoAbstract (sommario):
The efficiency of various variants of the component composition of alkaline electrolytes of plasma electrolytic oxidation (PEO) was studied. Technical liquid glass, NaOH, Na2B4O7, Na3PO4, and NaAlO2 were used as components of aqueous solutions. All of the studied components of electrolytes are the most common for use in PEO processes of aluminum alloys. The influence of the component composition of electrolytes on their stability during 30 days of exposure was evaluated, and the most stable compositions were selected. The structure and properties of coatings formed on samples of aluminum alloy AK6 during PEO are studied. The dependences of the hardness of coatings and their growth rate on the composition of the electrolyte are established. Possible variants of coating growth in the PEO process with different component composition of electrolytes are proposed.
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Marquez-Montes, Raul A., Kenta Kawashima, Yoon Jun Son, Grace Castelino, Nathan Miller, Lettie A. Smith, Chikaodili E. Chukwuneke e Charles Buddie Mullins. "(General Student Poster Award Winner - 1st Place) Six Practices to Improve Alkaline Electrolyte Preparation". ECS Meeting Abstracts MA2023-01, n. 55 (28 agosto 2023): 2695. http://dx.doi.org/10.1149/ma2023-01552695mtgabs.
Testo completoAbstract (sommario):
Alkaline electrolytes represent a critical component of electrochemical energy devices, including alkaline electrolyzers, fuel cells, supercapacitors, and alkaline batteries. In addition, these electrolytes define essential properties of electrocatalytic reactions, such as the oxygen evolution reaction (OER), the hydrogen evolution reaction (HER), and the oxygen reduction reaction (ORR). However, alkaline electrolyte concentrations and compositions are often considered trivial, resulting in misinterpretation of different phenomena and overestimating critical performance metrics. Thus, in an expanding field full of interdisciplinary research groups, there is an urgent need for standardized protocols designed to improve and evaluate the quality of alkaline electrolytes so that electrochemical energy systems can be objectively examined and compared. In this work, we propose a protocol composed of six steps to prepare, characterize and validate the quality of common alkaline electrolytes. By adapting well-established methods in the literature and validating additional features experimentally, we standardize six general practices: (1) proper alkaline electrolyte handling and preparation, (2) removal of Fe impurities, (3) alkali molarity standardization via pH titrations, (4) electrolyte composition analysis via inductively-coupled plasma mass spectrometry (ICP-MS), (5) statistical quality control assessment and (6) electrolyte validation through electrochemical aging of Ni electrodes in alkaline media. The effects of Fe incorporation for different alkaline electrolytes were examined using Ni and NiFe foam electrodes. Furthermore, ICP-MS measurements were complemented with prolonged cyclic voltammetry tests to confirm the effectiveness of the Fe purification procedure. We believe this work illustrates the importance of standardizing protocols and reporting reliable quality metrics to improve consistency and accuracy in electrochemistry. Furthermore, adopting the practices presented in this work would greatly benefit the evaluation and comparison of electrochemical energy materials and devices operating with alkaline electrolytes. Figure 1
26
FOMICHEV, V. T., A. V. SAVCHENKO, G. P. GUBAREVICH e E. E. EVDOKIMOV. "INFLUENCE OF PULSED CURRENT ON THE STRUCTURE OF COPPER-NICKEL ALLOY DEPOSIT". IZVESTIA VOLGOGRAD STATE TECHNICAL UNIVERSITY, n. 6(289) (giugno 2024): 93–98. http://dx.doi.org/10.35211/1990-5297-2024-6-289-93-98.
Testo completoAbstract (sommario):
The compositions of the main components of copper, zinc and brass ethylenediamine electrolytes were studied for the electrochemical characteristics of the electrolysis process and the properties of the resulting coatings. The optimal composition of ethylenediamine electrolyte for brass plating has been proposed.
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Saravanan, K. G., R. Prabu, A. R. Venkataramanan e Eden Tekle Beyessa. "Impact of Different Electrolytes on the Machining Rate in ECM Process". Advances in Materials Science and Engineering 2021 (30 agosto 2021): 1–6. http://dx.doi.org/10.1155/2021/1432300.
Testo completoAbstract (sommario):
Electrochemical machining is a nonconventional machining process in which the metal removal is achieved by the electricity and chemical solution known as an electrolyte. It is the reverse electrolysis process where the application of electricity facilitates the current travel in between anode and cathode. The mechanism of the ion movement is similar to the electrolysis process. Electrochemical machining (ECM) is a type of advanced machining process which employs electricity to perform the machining process on the workpiece. It is also known as a reverse electroplating process where metal removal is achieved instead of metal deposition on the metal surface. There are various parameters that affect the metal removal process in the ECM process, such as electrolyte, power supply, workpiece material, and tool material. The electrolyte is one of the key factors impacting the machining rate, surface finish, and reliability of the produced parts. In this project, a brief study is carried out regarding the electrochemical process and the electrolytes where the properties, functions, merits, and demerits are evaluated. The impact of the various electrolytes and their suitability for machining of various metals is also discussed. The findings of the effect produced by using the mixture of the electrolyte in the electrochemical machining process are discussed in this project. The effects of the complexing agents on the electrolyte and the electrochemical process as a whole are also reviewed.
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Kohl, Paul, Habin Park e Parin Shah. "(Invited) Anode and Cathode Self-Adhesive Ionomers for Durable Alkaline Water Electrolysis". ECS Meeting Abstracts MA2023-02, n. 6 (22 dicembre 2023): 902. http://dx.doi.org/10.1149/ma2023-026902mtgabs.
Testo completoAbstract (sommario):
Low-temperature water electrolysis using anion conductive polymer electrolytes has several potential advantages over acid-based polymer electrolyzers. However, the formation of durable, high surface area electrodes remains a challenge. The adhesion and connectivity of high surface area, particulate catalysts to the porous transport layer is critically important to the long-term cell lifetime. The water-fed, oxygen-evolving anode and dry hydrogen-evolving cathode has their own unique challenges in terms of catalyst adhesion, water uptake and ionic conductivity. In this study, a family of covalently bonded, self-adherent, hydroxide conducting ionomers has been synthesized and tested under alkaline electrolysis conditions. The ionomers are based on hydroxide conducting poly(norbornene) terpolymers used in fuel cell and electrolyzers. Ionomers used in electrolysis electrodes must provide adhesion between the catalyst particles, porous transport layer and solid polymer membrane. Adhesion is especially important at the oxygen producing anode because of the intra-electrode forces created during the volumetric expansion of the liquid water into oxygen gas. However, the need for high ion conductivity is eased due to the supporting electrolyte in the water feed. The hydrogen-evolving cathode does not experience the same liquid-to-gas forces, but requires higher water uptake and ion conductivity because it is run without liquid or gas feed. The terpolymer and tetrapolymer ionomers used in this work have been functionalized to provide cites for chemical bonding to the ionomer, catalyst, and porous transport layer. The resulting electrodes show excellent adhesion of the catalyst particles to the porous transport layer, as determined by adhesion and electrolyzer durability measurements. The anode and cathode ionomers have been customized for each electrode.
29
Castellani, Pablo, Clement Nicollet, Eric Quarez, Olivier Joubert e Annie Le Gal La Salle. "Synthesis of Yttrium Doped Barium Zirconate/Cerate Electrolyte Materials and Densification Using Conventional and Cold-Sintering Processes". ECS Transactions 109, n. 13 (30 settembre 2022): 13–29. http://dx.doi.org/10.1149/10913.0013ecst.
Testo completoAbstract (sommario):
Compared to high temperature solid oxide electrolysis cell, usually based on Yttrium stabilized Zirconia electrolytes, intermediate temperature proton conducting electrolysis cell, allows the production of water free hydrogen and a better chemical stability. Proton conducting perovskite materials, such as Barium Indates, Zirconates or Cerates are nearly commercial electrolytes for such devices. At intermediate temperature and under humid atmosphere, hydration process allows diffusion of protonic charges. Such electrolyte material combines a low thermal expansion coefficient and a high protonic conductivity. and The Zirconium rich material BaZr0.7Ce0.2Y0.1O3-δ that shows a conductivity around 10-2 S.cm-1 at 500°C will be compared to the Cerium rich BaZr0.3Ce0.6Y0.1O3-δ material that shows conductivities around 10-4 S.cm-1 at the same temperature.
30
Чабан, С., О. Ковра e В. Петров. "ВІДНОВЛЕННЯ ШТОКІВ СИЛОВИХ ГІДРОЦИЛІНДРІВ АВТОМОБІЛІВ ЛЕКТРОЛІТИЧНИМ ХРОМУВАННЯМ". Collection of scientific works of Odesa Military Academy, n. 19 (30 giugno 2023): 126–33. http://dx.doi.org/10.37129/2313-7509.2023.19.126-133.
Testo completoAbstract (sommario):
The quality of the repair of parts of military equipment and the increase of their service life largely depends on how it is organized and in what ways the restoration of malfunctioning or damaged parts is carried out. To restore the full functionality of the damaged parts, it is necessary to return them to their initial dimensions, geometric shape, hardness, corrosion resistance and other properties. One of the progressive methods of restoring the working rods of hydraulic cylinders is the application of electrolytic coatings on their working surface. The purpose of the study is to improve the method of restoration of hydraulic cylinder rods by electrolytic chroming with the aim of intensifying the process, improving operational properties and obtaining electrolytic chromium deposits of uniform thickness on the restored rods. The scientific and practical direction of the work consists in the fact that for the first time the technology of process intensification, improvement of the quality of coatings and obtaining of electrolytic chromium deposits uniform in length with the use of an ejector anode design has been considered. The research methodology is to identify the influence of the chrome plating process parameters on the uniformity, microhardness and microcracking of chrome coatings made of universal (250 г/л – СrO3; 2,5 г/л – H2SO4) та кріолітового (10 г/л – Na3AlF6; 250 г/л – СrO3; 2,5 г/л – H2SO4) of electrolytes by the ejector method. The results of the study are the establishment of the dependence of uniformity, microhardness and microcracking on the parameters of the ejector chromium plating process in standard and cryolite electrolytes and the determination of the optimal temperature and current density for use in restoring the rods of hydraulic cylinders of military equipment. The value of the conducted research is that for the first time an ejector anode is used as a positive electrode, which ensures obtaining high-quality and uniform electrolytic coatings directly in the chrome plating bath. Anode-ejector provides height-adjustable suspension suction of gaseous products of electrolysis and renewal of electrolyte in the interelectrode space due to the ejector effect in the anode tubes when the electrolyte is passed under pressure in the jet tubes. Keywords: stom density, anode-cathode distance, uniformity, cracking, microhardness, electrolyte temperature, anode-ejector.
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Badi, Nacer, Azemtsop Manfo Theodore, Saleh A. Alghamdi, Hatem A. Al-Aoh, Abderrahim Lakhouit, Pramod K. Singh, Mohd Nor Faiz Norrrahim e Gaurav Nath. "The Impact of Polymer Electrolyte Properties on Lithium-Ion Batteries". Polymers 14, n. 15 (30 luglio 2022): 3101. http://dx.doi.org/10.3390/polym14153101.
Testo completoAbstract (sommario):
In recent decades, the enhancement of the properties of electrolytes and electrodes resulted in the development of efficient electrochemical energy storage devices. We herein reported the impact of the different polymer electrolytes in terms of physicochemical, thermal, electrical, and mechanical properties of lithium-ion batteries (LIBs). Since LIBs use many groups of electrolytes, such as liquid electrolytes, quasi-solid electrolytes, and solid electrolytes, the efficiency of the full device relies on the type of electrolyte used. A good electrolyte is the one that, when used in Li-ion batteries, exhibits high Li+ diffusion between electrodes, the lowest resistance during cycling at the interfaces, a high capacity of retention, a very good cycle-life, high thermal stability, high specific capacitance, and high energy density. The impact of various polymer electrolytes and their components has been reported in this work, which helps to understand their effect on battery performance. Although, single-electrolyte material cannot be sufficient to fulfill the requirements of a good LIB. This review is aimed to lead toward an appropriate choice of polymer electrolyte for LIBs.
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Zhou, Hangyang. "Research Progress on Improvement Strategies of Polymer Electrolytes in Solid-State Batteries". Highlights in Science, Engineering and Technology 116 (7 novembre 2024): 302–7. http://dx.doi.org/10.54097/fyphrv62.
Testo completoAbstract (sommario):
The solid electrolyte material can replace the liquid electrolyte in the lithium-ion batteries, which ensures higher safety due to the flammable and corroded of liquid electrolyte. The polymer electrolytes demonstrated feasibility due to its suitable ductility. However, lithium ions in the polymer electrolytes are more difficult to ionize, resulting in worse ionic conductivity. At the same time, the mechanical strength of polymer electrolytes is not as good as that of inorganic electrolytes, which is not enough to inhibit the penetration of lithium dendrite. To solve these problems, researchers adopt two strategies: adding fillers or reactants and constructing artificial interface layers, focusing on improving ionic conductivity and mechanical strength. Based on the latest research, the problems faced by polymer electrolytes and improvement measures are reviewed, which provide references for the future development of polymer electrolytes.
33
Fu, Wen, Li Wang e Li Chen. "The Discharge Characteristics of PEO Films in K2ZrF6 with H3PO4 Electrolyte". Advanced Materials Research 461 (febbraio 2012): 277–80. http://dx.doi.org/10.4028/www.scientific.net/amr.461.277.
Testo completoAbstract (sommario):
The discharge characteristics of the potassium fluorozirconate electrolyte during plasma electrolytic oxidation process were investigated. Phosphoric acid was applied as additives. Ceramic films were prepared on magnesium alloy in electrolytes with different content additives under constant voltage. The effect of additives on the pH of the electrolyte and the dissolution of the substrate were investigated. It was found that the additives could influence the pH and dissolved magnesium ions effectively.
34
Fu, Wen, Li Wang e Li Chen. "The Discharge Characteristics of PEO Films in K2ZrF6 with NaH2PO4 Electrolyte". Advanced Materials Research 577 (ottobre 2012): 115–18. http://dx.doi.org/10.4028/www.scientific.net/amr.577.115.
Testo completoAbstract (sommario):
The discharge characteristics of the potassium fluorozirconate electrolyte during plasma electrolytic oxidation process were investigated. Sodium dihydrogen phosphate was applied as additives. Ceramic films were prepared on magnesium alloy in electrolytes with different content additives under constant voltage. The effect of additives on the pH of the electrolyte and the dissolution of the substrate were investigated. It was found that the additives could influence the pH and dissolved magnesium ions effectively.
35
Kamaluddin, Norashima, Famiza Abdul Latif e Chan Chin Han. "The Effect of HCl Concentration on the Ionic Conductivity of Liquid PMMA Oligomer". Advanced Materials Research 1107 (giugno 2015): 200–204. http://dx.doi.org/10.4028/www.scientific.net/amr.1107.200.
Testo completoAbstract (sommario):
To date gel and film type polymer electrolytes have been widely synthesized due to their wide range of electrical properties. However, these types of polymer electrolytes exhibit poor mechanical stability and poor electrode-electrolyte contact hence deprive the overall performance of a battery system. Therefore, in order to indulge the advantages of polymer as electrolyte, a new class of liquid-type polymer electrolyte was synthesized and investigated. To date this type of polymer electrolytre has not been extensively studied. This is due to the unavailability of liquid polymer for significance application. In this study, liquid poly (methyl methacrylate) (PMMA) electrolyte was synthesized using the simplest free radical polymerization technique using benzoyl peroxide as the initiator. It was found that this liquid PMMA oligomer has potential as electrolyte in proton battery when doped with small volume of various molarity of hydrochloric acid (HCl) in which the highest ionic conductivity achieved was 10-7 S/cm at room temperature. The properties of this liquid PMMA oligomer were further investigated using Fourier Transform Infrared Spectroscopy (FTIR).
36
Liu, Liyu, Kai Chen, Liguo Zhang e Bong-Ki Ryu. "Prospects of Sulfide-Based Solid-State Electrolytes Modified by Organic Thin Films". International Journal of Energy Research 2023 (6 febbraio 2023): 1–7. http://dx.doi.org/10.1155/2023/2601098.
Testo completoAbstract (sommario):
Lithium-ion batteries are key to tackling today’s energy crisis. In recent years, compared with the research on other components of lithium-ion batteries, the research on solid-state electrolytes is particularly hot. Among various solid-state electrolyte modification measures, we found that the material design of organic/inorganic composite flexible solid-state electrolytes can achieve the best all-solid-state battery cycling performance. Based on the study of sulfide-based organic/inorganic composite solid-state electrolytes, this article firstly introduces the classification of inorganic solid electrolytes and the advantages and disadvantages of each type of materials. At the same time, the research progress of various oxide solid electrolyte materials and sulfide solid electrolyte materials in recent years is introduced as well as the advantages of organic/inorganic composite solid-state electrolyte materials. Then the influencing factors that affect the performance of solid-state electrolytes, such as material lattice, lattice defects, electrolyte interface problems, and electrolyte microcracks, are introduced. Finally, the superiority of the industrial electrochemical performance of the organic/inorganic composite solid electrolyte material and its future prospects are introduced.
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Zaikov, Yu P., V. P. Batukhtin, N. I. Shurov e A. V. Suzdaltsev. "High-temperature electrochemistry of calcium". Electrochemical Materials and Technologies 1, n. 1 (2022): 20221007. http://dx.doi.org/10.15826/elmattech.2022.1.007.
Testo completoAbstract (sommario):
Electrolytically produced calcium is one of the most demanded materials in obtaining pure materials. At the same time, the existing technologies and devices for the electrolytic production of calcium were developed in the last century, and at present there are practically no works aimed at optimizing them. However, increasing the capacity and efficiency of existing devices for the production of calcium is in demand. To analyze possible ways to improve calcium production, a comprehensive understanding of the processes occurring at the electrodes and in the electrolyte during electrolytic production of calcium is required. This review briefly outlines the main points concerning the electrolytic production of calcium: from a brief history of the development of methods for the electrolytic production of calcium and established ideas about its physicochemical processes to information about new developments using the electrolysis of CaCl<sub>2</sub>-based melts. Review content: brief history of process development; base electrolyte for calcium production, including preparation of CaCl<sub>2</sub> and influence of additions on it physicochemical properties; data on calcium solubility in CaCl<sub>2</sub>; information about alternative electrolytes for calcium production; short description of electrode processes in the CaCl<sub>2</sub>-based melts; proposed technologies and devices for the electrolytic production of calcium.
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Carmona, Eric A., e Paul Albertus. "Solid-State Electrolyte Fracture in Lithium Metal Batteries". ECS Meeting Abstracts MA2022-02, n. 4 (9 ottobre 2022): 396. http://dx.doi.org/10.1149/ma2022-024396mtgabs.
Testo completoAbstract (sommario):
Next generation batteries utilizing solid-state electrolytes to enable use of lithium metal electrodes are of significant interest due to increased energy density and the potential safety enhancements. Despite their high yield strength, high room temperature ionic conductivity, and lack of reactivity with metallic lithium, these ceramic solid electrolytes are still prone to dendrite formation and subsequent cell failure above critical current densities. One experimentally observed dendrite formation and propagation mechanism requires mechanical failure of the electrolyte via fracture. Ceramic solid electrolyte’s do not undergo ductile deformation, leaving fracture as the primary means of stress relaxation. The electrolyte’s propensity to fracture is dependent on its material properties (i.e. fracture toughness), electrode mechanical properties, and the cell operating conditions (e.g. applied current density, stack pressure, temperature). This talk will focus on electrochemical-mechanical coupling (including thermodynamic and kinetic couplings of mechanical forces with electrochemical behavior) and the relationship between the current distribution, developed stresses, and solid-electrolyte fracture initiation at Li protrusions. The effect of current focusing on stress-driven fracture, plastic deformation of lithium, and the influence of mechanical boundary conditions will be described.
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Wu, Shi Kui, e Li Wang. "The Plasma Electrolytic Oxidation Process in K2ZrF6 with Na2HPO4 Electrolyte". Advanced Materials Research 602-604 (dicembre 2012): 1387–90. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.1387.
Testo completoAbstract (sommario):
The plasma electrolytic oxidation(PEO) process of the potassium fluorozirconate electrolyte were investigated with disodium hydrogen phosphate used as additives. Ceramic films were prepared on magnesium alloy in electrolytes with different content of disodium hydrogen phosphate under constant voltage. The effect of disodium hydrogen phosphate on the pH of the electrolyte and the dissolution of the substrate were investigated. It was found that disodium hydrogen phosphate could influence the pH and dissolved magnesium ions significantly.
40
Kanai, Yamato, Koji Hiraoka, Mutsuhiro Matsuyama e Shiro Seki. "Chemically and Physically Cross-Linked Inorganic–Polymer Hybrid Solvent-Free Electrolytes". Batteries 9, n. 10 (26 settembre 2023): 492. http://dx.doi.org/10.3390/batteries9100492.
Testo completoAbstract (sommario):
Safe, self-standing, all-solid-state batteries with improved solid electrolytes that have adequate mechanical strength, ionic conductivity, and electrochemical stability are strongly desired. Hybrid electrolytes comprising flexible polymers and highly conductive inorganic electrolytes must be compatible with soft thin films with high ionic conductivity. Herein, we propose a new type of solid electrolyte hybrid comprising a glass–ceramic inorganic electrolyte powder (Li1+x+yAlxTi2−xSiyP3−yO12; LICGC) in a poly(ethylene)oxide (PEO)-based polymer electrolyte that prevents decreases in ionic conductivity caused by grain boundary resistance. We investigated the cross-linking processes taking place in hybrid electrolytes. We also prepared chemically cross-linked PEO/LICGC and physically cross-linked poly(norbornene)/LICGC electrolytes, and evaluated them using thermal and electrochemical analyses, respectively. All of the obtained electrolyte systems were provided with homogenous, white, flexible, and self-standing thin films. The main ionic conductive phase changed from the polymer to the inorganic electrolyte at low temperatures (close to the glass transition temperature) as the LICGC concentration increased, and the Li+ ion transport number also improved. Cyclic voltammetry using [Li metal|Ni] cells revealed that Li was reversibly deposited/dissolved in the prepared hybrid electrolytes, which are expected to be used as new Li+-conductive solid electrolyte systems.
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Rakhadilov, Bauyrzhan, e Daryn Baizhan. "Creation of Bioceramic Coatings on the Surface of Ti–6Al–4V Alloy by Plasma Electrolytic Oxidation Followed by Gas Detonation Spraying". Coatings 11, n. 12 (23 novembre 2021): 1433. http://dx.doi.org/10.3390/coatings11121433.
Testo completoAbstract (sommario):
In this work, bioceramic coatings were formed on Ti6Al4V titanium alloy using a combined technique of plasma electrolytic oxidation followed by gas detonation spraying of calcium phosphate ceramics, based on hydroxyapatite. Plasma electrolytic oxidation was carried out in electrolytes with various chemical compositions, and the effect of electrolytes on the macro and microstructure, pore size and phase composition of coatings was estimated. Three types of electrolytes based on sodium compounds were used: phosphate, hydroxide, and silicate. Plasma electrolytic oxidation of the Ti–6Al–4V titanium alloy was carried out at a fixed DC voltage (270 V) for 5 min. The sample morphology and phase composition were studied with a scanning electron microscope and an X-ray diffractometer. According to the results, the most homogeneous structure with lower porousness and many crystalline anatase phases was obtained in the coating prepared in the silicate-based electrolyte. A hydroxyapatite layer was obtained on the surface of the oxide layer using detonation spraying. It was determined that the appearance of α-tricalcium phosphate phases is characteristic for detonation spraying of hydroxyapatite, but the hydroxyapatite phase is retained in the coating composition. Raman spectroscopy results indicate that hydroxyapatite is the main phase in the coatings.
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Ambika, C., G. Hirankumar, S. Thanikaikarasan, K. K. Lee, E. Valenzuela e P. J. Sebastian. "Influence of TiO2 as Filler on the Discharge Characteristics of a Proton Battery". Journal of New Materials for Electrochemical Systems 18, n. 4 (20 novembre 2015): 219–23. http://dx.doi.org/10.14447/jnmes.v18i4.351.
Testo completoAbstract (sommario):
Different concentrations of TiO2 dispersed nano-composite proton conducting polymer electrolyte membranes were prepared using solution casting technique. Fourier Transform Infrared Spectroscopic analysis was carried out to determine the vibrational investigations about the prepared membranes. Variation of conductivity due to the incorporation of TiO2 in polymer blend electrolyte was analyzed using Electrochemical Impedance Spectroscopy and the value of maximum conductivity is 2.8×10-5 Scm-1 for 1mol% of TiO2 dispersed in polymer electrolytes. Wagner polarization technique has been used to determine the value of charge transport number of the composite polymer electrolytes. The electrochemical stability window of the nano-composite polymer electrolyte was analyzed using Linear Sweep Voltammetry. Fabrication of Proton battery is carried out with configuration of Zn+ZnSO4.7H2O+AC ǁ Polymer electrolyte ǁ MnO2+AC. Discharge characteristics were investigated for polymer blend electrolytes and 1mol% TiO2 dispersed nano-composite polymer electrolytes at constant current drain of 10μA. There is evidence of enhanced performance for proton battery which was constructed using 1mol% TiO2 dispersed nano-composite polymer electrolytes compared to the blend polymer electrolytes.
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Yan, Yingchun, Zheng Liu, Xinhou Yang e Zhuangjun Fan. "Multilayer composite nanofibrous film accelerates the Li+ diffusion for quasi-solid-state lithium-ion batteries". IOP Conference Series: Earth and Environmental Science 1171, n. 1 (1 aprile 2023): 012034. http://dx.doi.org/10.1088/1755-1315/1171/1/012034.
Testo completoAbstract (sommario):
Abstract The rational design of dense and flexible solid-state electrolytes (SSEs) with interface compatibility is still challenging. Here, we report a three-layer dense 3D nanofibrous matrix (PCOF) by constructing a nanofiber framework combining polyacrylonitrile (PAN) and fast Li-ion conductor covalent organic frameworks (COFs) by electrospinning method. PCOF film can maintain an extraordinary electrolyte/electrode interface and an interconnected ion-conduction pathway, accelerating Li+ diffusion. The PCOF quasi-solid-state electrolyte (QSSE) has high oxidative stability (4.70 V, versus Li+/Li) and ion conductivity of 2.94×10−4 S cm−1 at room temperature. Lithium-ion battery based on PCOF QSSE with LiFPO4 (LFP) cathode exhibits outstanding rate characteristics and cycling stability. This multi-layer composite strategy will start a new area of QSSEs lithium-ion electrolytic devices, and simultaneously accelerate the design of electrolytes featuring a wide range of properties.
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Thangamani, Geethapriyan, Muthuramalingam Thangaraj, Khaja Moiduddin, Syed Hammad Mian, Hisham Alkhalefah e Usama Umer. "Performance Analysis of Electrochemical Micro Machining of Titanium (Ti-6Al-4V) Alloy under Different Electrolytes Concentrations". Metals 11, n. 2 (2 febbraio 2021): 247. http://dx.doi.org/10.3390/met11020247.
Testo completoAbstract (sommario):
Titanium alloy is widely used in modern automobile industries due to its higher strength with corrosion resistance. Such higher strength materials can be effectively machined using unconventional machining processes, especially the electro-chemical micro machining (ECMM) process. It is important to enhance the machining process by investigating the effects of electrolytes and process parameters in ECMM. The presented work describes the influence of three different combinations of Sodium Chloride-based electrolytes on machining Titanium (Ti-6Al-4V) alloy. Based on the ECMM process parameters such as applied voltage, electrolytic concentration, frequency and duty cycle on response, characteristics are determined by the Taguchi design of experiments. The highest material removal rate (MRR) was achieved by the Sodium Chloride and Sodium Nitrate electrolyte. The combination of Sodium Chloride and Citric Acid achieve highest Overcut and Circularity. The optimal overcut was observed from the Sodium Chloride and Glycerol electrolyte due to the presence of glycerol. The better conicity was obtained from Sodium Chloride and Citric Acid in comparison with other electrolytes. A Sodium Chloride and Glycerol combination could generate better machined surface owing to the chelating effect of Glycerol.
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Dubinin, P. S., I. S. Yakimov, A. S. Samoilo, S. G. Ruzhnikov, O. E. Bezrukova, A. N. Zaioga, S. D. Kirik e D. V. Khiystov. "Analytical appro aches in the development of industry standard specimens of aluminum production electrolyte". Industrial laboratory. Diagnostics of materials 88, n. 10 (24 ottobre 2022): 20–29. http://dx.doi.org/10.26896/1028-6861-2022-88-10-20-29.
Testo completoAbstract (sommario):
A combination of the methods of X-ray phase and X-ray spectral analyzes is used at domestic aluminum plants for operational technological control of the composition of cooled electrolytes. In this case, standard samples of chemical and phase composition are used to calibrate measuring instruments. The synthesis of standard samples from simple components is impossible due to the inadequacy of their microcrystalline structure to real electrolyte samples. Therefore, it is necessary to develop standard samples directly from the material of real electrolytes with a reliably established quantitative chemical and mineralogical phase composition. We managed to develop a set of 30 standard samples of aluminum-produced electrolyte using electrolytes taken from the electrolysis baths of various plants; some of the samples were doped with sodium, aluminum, calcium, and magnesium fluorides to expand the range of compositions. A metrological certification of the set with the status of "Industry standard samples" was performed based on the data of interlaboratory analysis according to the methods of X-ray control used at the plants and according to the well-known Rietveld X-ray phase method for determining the quantitative phase composition. The set has been successfully implemented at seven RUSAL plants.
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Yamada, Yuki. "(Invited) Design of Lithium Battery Electrolytes Based on Electrode Potentials". ECS Meeting Abstracts MA2023-02, n. 4 (22 dicembre 2023): 525. http://dx.doi.org/10.1149/ma2023-024525mtgabs.
Testo completoAbstract (sommario):
Lithium (Li) metal is an ideal battery anode with low electrode potential (-3.045 V vs. SHE) and high theoretical capacity (3860 mAh g-1, 2060 mAh cm-3). However, its critical problem is a low Coulombic efficiency (CE), which is caused the thermodynamic instability of a Li/electrolyte interface because of the strong reducing ability of Li metal. Since Li electrode potential (E Li) is located far below the cathodic limit of the electrolyte's potential window, the electrolyte components are inevitably reduced and decomposed on the Li metal anode (Fig. 1). Some of the decomposition products function as solid electrolyte interphase (SEI) to suppress further electrolyte decomposition. Various electrolytes and additives have been proposed to form a stable SEI on Li metal, which leads to higher CEs. However, the correlation between CE and SEI is still unclear. Here we report E Li as a quantitative and thermodynamic descriptor of the CEs of Li metal anodes.1 We measured E Li in various electrolytes with reference to 1 mM ferrocene as an internal standard. The obtained E Li varied significantly (up to 0.6 V) depending on electrolyte formulations. We also evaluated the CEs of Li plating/stripping in various electrolytes without ferrocene. Based on these results, we found that the CEs are correlated with E Li (Fig. 2). The CE increased with increasing E Li, suggesting that the reductive decomposition of electrolytes was suppressed at high E Li (lower reducing ability of Li). Theoretically, E Li is directly determined by the chemical potential of Li+ (μ Li+) in the electrolyte. Hence, E Li, that is the reducing ability of Li, can be controlled by designing an electrolyte focusing on μ Li+. Raman Spectroscopy revealed that the formation of ion pairs is essential for increasing the μ Li+ and upshifting the E Li. This finding provides fundamental science that can tune the μ Li+ and E Li to increase the CE of Li metal anodes. 1. Seongjae Ko, Tomohiro Obukata, Tatau Shimada, Norio Takenaka, Masanobu Nakayama, Atsuo Yamada, Yuki Yamada, Nat. Energy, 7, 1217-1224 (2022). Figure 1
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Park, Habin, Anthony Engler, Nian Liu e Paul Kohl. "Dynamic Anion Delocalization of Single-Ion Conducting Polymer Electrolyte for High-Performance of Solid-State Lithium Metal Batteries". ECS Meeting Abstracts MA2022-02, n. 3 (9 ottobre 2022): 227. http://dx.doi.org/10.1149/ma2022-023227mtgabs.
Testo completoAbstract (sommario):
Lithium metal batteries (LMBs) have been considered as next-generation energy storages due to their extremely high theoretical specific capacity (3860 mAh g-1). However, current LMBs, using conventional liquid electrolytes, still could not fulfill the demand of soaring expansion of energy era, such as electrical vehicles, because of their safety issues, originated by uncontrollable electrolytic side reaction on the lithium, resulting unstable solid-electrolyte interphase (SEI) and vicious lithium dendritic growth [1]. Also, carbonate-based liquid electrolytes have an intrinsic flammability, and the lithium dendrite, which short-circuits a cell, can lead to severe safety hazard with the unfavorable flammability of current liquid system when they are ignited. Therefore, solid-state electrolytes have been spotlighted recently for a pathway for safe, and high energy and power LMBs, due to their superior thermal stability and low vapor pressure, while maintaining suitable electrolytic performances. In this study, solid-state single-ion conducting polymer electrolytes (SICPEs), utilizing dynamic anion delocalization (DAD), realizing high ionic conductivity and dimensional stability for high-performance LMB, are studied. The SICPEs enable superior lithium transference number, resulting in highly reduced concentration gradient of lithium cation along the electrolyte to suppress the undesirable lithium dendritic growth. However, SICPEs have prominently lower ionic conductivity than dual-ion conducting polymer electrolyte (DICPEs), which is a critical issue to make a slower charge/discharge for SICPEs [2]. Although an approach utilizing gel polymer electrolyte (GPE), using a liquid solvent as a plasticizer, has been exploited to increase the ionic conductivity of SICPEs, GPEs have struggled with lower mechanical stability, compared to solid state, and still existing flammability issue with the plasticizer. The novel plasticizer, which is described here, can interact with bulky anionic polymer matrix, so that the negative charge can be dispersed onto the whole complex by DAD. Once the bulky complex is formed by DAD, the dissociation of lithium cation from anionic matrix can be easier with the decreased activation energy and higher ionic conduction. While increasing the ionic conductivity with DAD, the nature of polymeric plasticizer will highly suppress flammability. DAD allows the membrane endure more tensile strength due to the dynamic structural change in crosslinking state, so that the polymer electrolyte can tolerate dendritic growth of lithium by morphological change on an electrode surface. The obvious advantages of DAD-induced solid polymer electrolytes in this study for a high energy and power, and ultra-safe LMB can present a novel approach of polymer electrolyte design to the astronomical demand of energy storages. [1] F. Ahmed, I. Choi, M.M. Rahman, H. Jang, T. Ryu, S. Yoon, L. Jin, Y. Jin, W. Kim, ACS Appl. Mater. Interfaces 2019, 11, 34930-34938. [2] D.-M. Shin, J.E. Bachman, M.K. Taylor, J. Kamcev, J.G. Park, M.E. Ziebel, E. Velasquez, N.N. Jarenwattananon, G.K. Sethi, Y. Cui, J.R. Long, Adv. Mater. 2020, 32, 1905771.
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Fenner, Emily, Elizabeth Allan-Cole, Rachel Garman e Michael F. Toney. "Characterization of Degradation Mechanisms of Alternative Electrolytes Solutions in Fast Charging Li-Ion Batteries". ECS Meeting Abstracts MA2024-01, n. 5 (9 agosto 2024): 725. http://dx.doi.org/10.1149/ma2024-015725mtgabs.
Testo completoAbstract (sommario):
While the idea that fast charging batteries could be utilized in electric vehicles is enticing, current fast charging batteries face significant challenges that must be mitigated before this application is realized. Fast charging batteries currently suffer from capacity loss and degradation over time which not only affects battery life but poses a safety hazard. The current electrolyte, 1.2 M LiPF6 in 3:7 wt.% EC/EMC (Gen2), contains the salt LiPF6 that when exposed to moisture can form dangerous hydrofluoric acid and contains a carbonate-based solvent that when exposed to oxygen can ignite. In addition, batteries experience degradation over many cycles of fast charging which results in capacity fade and poor battery performance. However, previous studies have shown the potential for other electrolyte systems to mitigate these problems, specifically by using highly concentrated electrolytes1. These studies claim that using these electrolytes results in the formation of a solid electrolyte interphase (SEI) that passivates Li ions better than the Gen2 electrolyte. The SEI is a layer that forms on the anode within the battery and serves as a protective layer that allows for Li intercalation into graphite and can therefore protect against degradation. By using different electrolytes, a different SEI is formed, and different degradation mechanisms are observed. In this way, the SEI can be tuned to improve Li passivation and ionic conductivity by changing the electrolyte’s composition and concentration2. This research focuses on such alternative electrolyte systems and aims to characterize the different degradation mechanisms corresponding to each electrolyte. Favorable performance has been observed using 1.2 M LiFSI in 3:7 wt.% EC/EMC as an electrolyte. We are studying LiFSI in acetonitrile (AN) at higher concentrations than traditional Gen2 to quantify the SEI. We expect AN to form an anion derived SEI, a composition of which results in improved passivation of Li ions1. In this study, we characterize degradation of alternative electrolyte systems through x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Through these methods we can observe and quantify both crystalline, amorphous degradation products due to loss of Li inventory and loss of active material. XPS allows quantification of compositional changes in the SEI layer at the surface of the electrode. The SEM provides qualitative information on degradation such as visualizing lithium plating and dendrite formation. We implement quantitative XRD to measure the crystalline phases of the graphite anode, showing the degree of lithium intercalation and further quantifying degradation such as Li plating. Putting the results of these three characterization techniques together in tandem with electrochemical cycling data paints a picture of the degradation that happens on the anode of a fast-charging lithium-ion battery with respect to electrolyte composition. [1] Yamada, Y., Wang, J., Ko, S., Watanabe, E., & Yamada, A. (2019). Advances and issues in developing salt- concentrated battery electrolytes. Nature Energy. [2] Logan, E. R., & Dahn, J. R. (2020). Electrolyte Design for Fast-Charging Li-ion Batteries. Trends in Chemistry.
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Chen, Xuecheng, e Rudolf Holze. "Polymer Electrolytes for Supercapacitors". Polymers 16, n. 22 (13 novembre 2024): 3164. http://dx.doi.org/10.3390/polym16223164.
Testo completoAbstract (sommario):
Because of safety concerns associated with the use of liquid electrolytes and electrolyte solutions, options for non-liquid materials like gels and polymers to be used as ion-conducting electrolytes have been explored intensely, and they attract steadily growing interest from researchers. The low ionic conductivity of most hard and soft solid materials was initially too low for practical applications in supercapacitors, which require low internal resistance of a device and, consequently, highly conducting materials. Even if an additional separator may not be needed when the solid electrolyte already ensures reliable separation of the electrodes, the electrolytes prepared as films or membranes as thin as practically acceptable, resistance may still be too high even today. Recent developments with gel electrolytes sometimes approach or even surpass liquid electrolyte solutions, in terms of effective conductance. This includes materials based on biopolymers, renewable raw materials, materials with biodegradability, and better environmental compatibility. In addition, numerous approaches to improving the electrolyte/electrode interaction have yielded improvements in effective internal device resistance. Reported studies are reviewed, material combinations are sorted out, and trends are identified.
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Eldesoky, A., A. J. Louli, A. Benson e J. R. Dahn. "Cycling Performance of NMC811 Anode-Free Pouch Cells with 65 Different Electrolyte Formulations". Journal of The Electrochemical Society 168, n. 12 (1 dicembre 2021): 120508. http://dx.doi.org/10.1149/1945-7111/ac39e3.
Testo completoAbstract (sommario):
Liquid electrolytes for anode-free Li metal batteries (LMBs) provide a cost-effective path to high energy density. However, liquid electrolytes are challenging due to the reactivity of Li0 with the electrolyte and the resulting Li loss, as well as mossy Li deposits leading to inactive Li and dendrite formation. Thus, more research is needed to develop electrolytes capable of 80 % capacity retention after 800 cycles to meet electric vehicle (EV) demands. Here, we report cycle life results from 65 electrolyte mixtures consisting of various additives or co-solvents added to a dual-salt base electrolyte previously reported by our group. We tested these electrolyte systems using a practical anode-free pouch cell design with a high-loading (16 mg cm−2, or 3.47 mAh cm-2) LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode, with a bare Cu foil as the counter electrode. All cells in this work were cycled at 40 °C with 0.2C/0.5C charge/discharge rates between 3.55–4.40 V. Based on the total energy delivered over 140 cycles, only four electrolytes showed marginal improvement over the baseline, while the other electrolytes were uncompetitive. This data set can serve as a guide for LMB researchers investigating electrolyte systems and highlights the challenges associated with liquid electrolytes.