The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Renaud Bouchet - One of the best experts on this subject based on the ideXlab platform.
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Electrochemical impedance spectroscopy of a Li–S battery: Part 2. Influence of Separator chemistry on the lithium electrode/electrolyte interface
Electrochimica Acta, 2017Co-Authors: Joanna Conder, Sigita Trabesinger, Claire Villevieille, Lorenz Gubler, Petr Novák, Renaud BouchetAbstract:Abstract Asymmetric Separators with polysulfide barrier properties, consisting of porous polypropylene (PP) grafted with styrene sulfonate (SS), PP-g-PLiSS, were characterized in symmetric Li/Li cells using electrochemical impedance spectroscopy to investigate the influence of Separator chemistry on the Li electrode/electrolyte interface. The symmetric Li/Li cell approach was found to be applicable for probing the transport properties of the Separator and, therefore, determining the role of the functionality added to the Separator. Electrolyte resistance and the formation of a surface film on metallic Li were both monitored as functions of time and the concentration of cation-exchange groups introduced at and near the surface of one side of the Separator (expressed as the graft level). No continuous build-up of Li electrode/electrolyte interface resistance was observed, indicating that the addition of a cation-exchange layer did not hinder entirely Li-ion transport through the Separator. In addition, the microstructures of the Separators were reconstructed based on focused ion beam/scanning electron microscopy tomography to determine the effective ionic conductivity and effective tortuosity of the PP-g-PLiSS Separators. These values showed that ion mobility within the Separator changed with increasing graft level, indicating that the concentration of SS groups and bulk porosity of the Separator have to be adjusted to maintain the effective conductivity at a practical level.
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electrochemical impedance spectroscopy of a li s battery part 2 influence of Separator chemistry on the lithium electrode electrolyte interface
Electrochimica Acta, 2017Co-Authors: Joanna Conder, Sigita Trabesinger, Renaud Bouchet, Claire Villevieille, Lorenz Gubler, Petr NovákAbstract:Abstract Asymmetric Separators with polysulfide barrier properties, consisting of porous polypropylene (PP) grafted with styrene sulfonate (SS), PP-g-PLiSS, were characterized in symmetric Li/Li cells using electrochemical impedance spectroscopy to investigate the influence of Separator chemistry on the Li electrode/electrolyte interface. The symmetric Li/Li cell approach was found to be applicable for probing the transport properties of the Separator and, therefore, determining the role of the functionality added to the Separator. Electrolyte resistance and the formation of a surface film on metallic Li were both monitored as functions of time and the concentration of cation-exchange groups introduced at and near the surface of one side of the Separator (expressed as the graft level). No continuous build-up of Li electrode/electrolyte interface resistance was observed, indicating that the addition of a cation-exchange layer did not hinder entirely Li-ion transport through the Separator. In addition, the microstructures of the Separators were reconstructed based on focused ion beam/scanning electron microscopy tomography to determine the effective ionic conductivity and effective tortuosity of the PP-g-PLiSS Separators. These values showed that ion mobility within the Separator changed with increasing graft level, indicating that the concentration of SS groups and bulk porosity of the Separator have to be adjusted to maintain the effective conductivity at a practical level.
Bruce E Logan - One of the best experts on this subject based on the ideXlab platform.
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electrochemical analysis of Separators used in single chamber air cathode microbial fuel cells
Electrochimica Acta, 2013Co-Authors: Justin C Tokash, Fang Zhang, Bruce E LoganAbstract:Abstract Polarization, solution-Separator, charge transfer, and diffusion resistances of clean and used Separator electrode assemblies were examined in microbial fuel cells using current–voltage curves and electrochemical impedance spectroscopy (EIS). Current–voltage curves showed the total resistance was reduced at low cathode potentials. EIS results revealed that at a set cathode potential of 0.3 V diffusion resistance was predominant, and it substantially increased when adding Separators. However, at a lower cathode potential of 0.1 V all resistances showed only slight differences with and without Separators. Used Separator electrode assemblies with biofilms had increased charge transfer and diffusion resistances (0.1 V) when one Separator was used; however, charge transfer resistance increased, and diffusion resistance did not appreciably change with four Separators. Adding a plastic mesh to compress the Separators improved maximum power densities. These results show the importance of pressing Separators against the cathode, and the adverse impacts of biofilm formation on electrochemical performance.
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scalable air cathode microbial fuel cells using glass fiber Separators plastic mesh supporters and graphite fiber brush anodes
Bioresource Technology, 2011Co-Authors: Xiaoyuan Zhang, Shaoan Cheng, Peng Liang, Xia Huang, Bruce E LoganAbstract:The combined use of brush anodes and glass fiber (GF1) Separators, and plastic mesh supporters were used here for the first time to create a scalable microbial fuel cell architecture. Separators prevented short circuiting of closely-spaced electrodes, and cathode supporters were used to avoid water gaps between the Separator and cathode that can reduce power production. The maximum power density with a Separator and supporter and a single cathode was 75 ± 1 W/m 3 . Removing the Separator decreased power by 8%. Adding a second cathode increased power to 154 ± 1 W/m 3 . Current was increased by connecting two MFCs connected in parallel. These results show that brush anodes, combined with a glass fiber Separator and a plastic mesh supporter, produce a useful MFC architecture that is inherently scalable due to good insulation between the electrodes and a compact architecture.
Joanna Conder - One of the best experts on this subject based on the ideXlab platform.
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Electrochemical impedance spectroscopy of a Li–S battery: Part 2. Influence of Separator chemistry on the lithium electrode/electrolyte interface
Electrochimica Acta, 2017Co-Authors: Joanna Conder, Sigita Trabesinger, Claire Villevieille, Lorenz Gubler, Petr Novák, Renaud BouchetAbstract:Abstract Asymmetric Separators with polysulfide barrier properties, consisting of porous polypropylene (PP) grafted with styrene sulfonate (SS), PP-g-PLiSS, were characterized in symmetric Li/Li cells using electrochemical impedance spectroscopy to investigate the influence of Separator chemistry on the Li electrode/electrolyte interface. The symmetric Li/Li cell approach was found to be applicable for probing the transport properties of the Separator and, therefore, determining the role of the functionality added to the Separator. Electrolyte resistance and the formation of a surface film on metallic Li were both monitored as functions of time and the concentration of cation-exchange groups introduced at and near the surface of one side of the Separator (expressed as the graft level). No continuous build-up of Li electrode/electrolyte interface resistance was observed, indicating that the addition of a cation-exchange layer did not hinder entirely Li-ion transport through the Separator. In addition, the microstructures of the Separators were reconstructed based on focused ion beam/scanning electron microscopy tomography to determine the effective ionic conductivity and effective tortuosity of the PP-g-PLiSS Separators. These values showed that ion mobility within the Separator changed with increasing graft level, indicating that the concentration of SS groups and bulk porosity of the Separator have to be adjusted to maintain the effective conductivity at a practical level.
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electrochemical impedance spectroscopy of a li s battery part 2 influence of Separator chemistry on the lithium electrode electrolyte interface
Electrochimica Acta, 2017Co-Authors: Joanna Conder, Sigita Trabesinger, Renaud Bouchet, Claire Villevieille, Lorenz Gubler, Petr NovákAbstract:Abstract Asymmetric Separators with polysulfide barrier properties, consisting of porous polypropylene (PP) grafted with styrene sulfonate (SS), PP-g-PLiSS, were characterized in symmetric Li/Li cells using electrochemical impedance spectroscopy to investigate the influence of Separator chemistry on the Li electrode/electrolyte interface. The symmetric Li/Li cell approach was found to be applicable for probing the transport properties of the Separator and, therefore, determining the role of the functionality added to the Separator. Electrolyte resistance and the formation of a surface film on metallic Li were both monitored as functions of time and the concentration of cation-exchange groups introduced at and near the surface of one side of the Separator (expressed as the graft level). No continuous build-up of Li electrode/electrolyte interface resistance was observed, indicating that the addition of a cation-exchange layer did not hinder entirely Li-ion transport through the Separator. In addition, the microstructures of the Separators were reconstructed based on focused ion beam/scanning electron microscopy tomography to determine the effective ionic conductivity and effective tortuosity of the PP-g-PLiSS Separators. These values showed that ion mobility within the Separator changed with increasing graft level, indicating that the concentration of SS groups and bulk porosity of the Separator have to be adjusted to maintain the effective conductivity at a practical level.
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Performance-Enhancing Asymmetric Separator for Lithium–Sulfur Batteries
2016Co-Authors: Joanna Conder, Lorenz Gubler, Antoni Forner-cuenca, Elisabeth Müller Gubler, Petr Novák, Sigita TrabesingerAbstract:Asymmetric Separators with polysulfide barrier properties consisting of porous polypropylene grafted with styrenesulfonate (PP-g-PLiSS) were characterized in lithium–sulfur cells to assess their practical applicability. Galvanostatic cycling at different C-rates with and without an electrolyte additive and cyclic voltammetry were used to probe the electrochemical performance of the cells with the PP-g-PLiSS Separators and to compare it with the performance of the cells utilizing state-of-the-art Separator, Celgard 2400. Overall, it was found that regardless of the applied cycling rate, the use of the grafted Separators greatly enhances the Coulombic efficiency of the cell. An appropriate Li-exchange-site (−SO3–) concentration at and near the surface of the Separator was found to be essential to effectively suppress the polysulfide shuttle without sacrificing the Li-ion mobility through the Separator and to improve the practical specific charge of the cell
Chuanwei Yan - One of the best experts on this subject based on the ideXlab platform.
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A Novel Self-Binding Composite Separator Based on Poly(tetrafluoroethylene) Coating for Li-Ion Batteries
Polymers, 2018Co-Authors: Kaiyue Zhang, Jianguo Liu, Wei Xiao, Chuanwei YanAbstract:In this study, a novel composite Separator based on polytetrafluoroethylene (PTFE) coating layers and a commercial polyethylene (PE) Separator is developed for high performance Li-ion batteries. This composite Separator is prepared by immersing a PE Separator directly into a commercial PTFE suspension to obtain a self-binding PTFE/PE/PTFE tri-layered structure. Then, the as-prepared composite Separator is further treated with a H₂O₂/H₂SO₄ solution to enhance its electrolyte affinity. The results show that the coating layer, consisting of close-packed PTFE particles, possesses a highly ordered nano-porous structure and an excellent electrolyte wettability property, which significantly enhance the ionic conductivity of the composite Separator. Due to the presence of the PTFE-based coating layer, the composite Separator exhibits better thermal stability compared with the PE Separator, reaching the thermal-resistant grade of commercial ceramic-coated Separators. By using different Separators, CR2032-type unit half-cells composed of a Li anode and a LiFePO₄ cathode were assembled, and their C-rate and cycling performances were evaluated. The cell assembled with the composite Separator was proven to have better C-rate capability and cycling capacity retention than the cell with the polyethylene Separator. It is expected that the composite Separator can be a potential candidate as a coating-type Separator for high-performance rechargeable Li-ion batteries.
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organic inorganic binary nanoparticle based composite Separators for high performance lithium ion batteries
New Journal of Chemistry, 2016Co-Authors: Wei Xiao, Jianguo Liu, Hong Wang, Yaqun Gong, Chuanwei YanAbstract:In an effort to improve the thermal resistance and the electrochemical performances of Separators for lithium-ion batteries, we demonstrate a facile approach to prepare a novel ZrO2/poly(vinylidene fluoride-co-hexafluoro-propylene) (PVdF-HFP) binary particle-coated polyethylene terephthalate (PET) nonwoven composite Separator. In this approach, particle-shaped PVdF-HFP was used as a binder for the first time to attach ZrO2 particles to a PET nonwoven substrate by a solvent vapor-induced bonding process. This method can improve the microstructure and surface properties of the composite Separator compared with the conventional film-shaped polymer binder. The electrolyte wettability, ionic conductivity and thermal stability of the ZrO2/PVdF-HFP composite Separator are superior to those of commercially available microporous polyolefin Separators due to the well-connected three-dimensional porous structure and the electrolyte-philic surface properties of the composite Separator. As a result, the cells assembled with the composite Separator exhibit better cell performance such as the discharge C-rate capability and cycling performance, compared with those assembled with polyolefin-based Separators. Conspicuously, the improved performance of the ZrO2/PVdF-HFP Separator indicates that binary particle-based composite Separators could be potentially applied in next generation lithium-ion batteries.
H.a. Lingscheidt - One of the best experts on this subject based on the ideXlab platform.
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Impact of Separator design on the performance of gelled-electrolyte valve-regulated lead/acid batteries
Journal of Power Sources, 1997Co-Authors: A.l. Ferreira, H.a. LingscheidtAbstract:The special requirements of Separators used in the manufacture of gelled valve-regulated lead/acid (VRLA) batteries start at the cell-processing steps, where the Separator must assist, through its characteristics, the formation of an optimal gel structure. In a gelled VRLA cell, conditions exist that pose additional demands on the Separators. In this type of cell, the Separator is not a by-stander, but an integral link in the chain of events that comprise the establishment of an efficient oxygen-recombination cycle. In the work reported here, the need for Separator materials of very high porosity will be demonstrated, as well as the need for optimal pore-size distributions. An examination is also made of the effect of the surface characteristics of the Separator on the formation of gel micro-channels and, in term, the efficiency of the oxygen cycle.
