The Experts below are selected from a list of 108750 Experts worldwide ranked by ideXlab platform
Zhou Qing-shen - One of the best experts on this subject based on the ideXlab platform.
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Application of Separators in valve-regulated lead acid batteries
Chinese Journal of Power Sources, 2007Co-Authors: Zhou Qing-shenAbstract:The manufacturing performance and new products of Separators were introduced; effect of additives on separator was discussed briefly. The causes of formation on PCL of VRLA batteries were analyzed, skills of AGM Separators in VRLA batteries was supposed. And the effect of separator on gel battery life was discussed.
Xiaosong Huang - One of the best experts on this subject based on the ideXlab platform.
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A multilayer composite separator consisting of non-woven mats and ceramic particles for use in lithium ion batteries
Journal of Solid State Electrochemistry, 2014Co-Authors: Xiaosong Huang, Donna Bahroloomi, Xinran XiaoAbstract:Battery separator is a porous membrane that is placed between the positive and negative electrodes to avoid their electric contact, while maintaining a good ionic flow through the liquid electrolyte filled in its pores. Non-woven mats have been evaluated as battery Separators due to their highly porous structures. In this study, composite non-woven mats were fabricated through electrospinning and lamination with a ceramic layer, and evaluated as lithium ion battery Separators. The lamination with the ceramic layer provides not only improved separator dimensional stability at elevated temperatures but also the potential to increase the production rate of electrospun Separators. The electrospun mats keep ceramic particles from dropping avoiding the non-uniform current density distribution caused by the loss of the ceramic particles. The composite Separators enabled good ionic conductivity when saturated with a liquid electrolyte. Coin cells with this type of Separators showed not only stable cycling performance but also good rate capabilities at room temperature.
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Lithium ion battery Separators: Development and performance characterization of a composite membrane
Journal of Membrane Science, 2013Co-Authors: Xiaosong Huang, Jonathon HittAbstract:Abstract The overall stability of the lithium ion battery Separators, under potentially extreme battery operating conditions, will require leading edge design and fabrication techniques to exceed manufacturing and end performance requirements for large scale applications. This paper features the development and performance characterization of an inorganic fiber enhanced composite separator for LIBs. This composite separator can offer a thermally stable alternative for conventional porous polyolefin Separators, which shrink significantly at high temperatures. The relative affinities between the electrolyte and the submicron inorganic fibers and the electrolyte and the polyvinylidene fluoride binder ensured a superior wettability of the final separator by the liquid electrolyte. The high porosity and the open porous structure of the composite separator resulted in a good effective ionic conductivity. Coin cells with this composite separator also exhibited stable cycle performance and improved rate capabilities, especially when discharged at rates greater than C/2.
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Separator technologies for lithium-ion batteries
Journal of Solid State Electrochemistry, 2010Co-Authors: Xiaosong HuangAbstract:Although Separators do not participate in the electrochemical reactions in a lithium-ion (Li-ion) battery, they perform the critical functions of physically separating the positive and negative electrodes while permitting the free flow of lithium ions through the liquid electrolyte that fill in their open porous structure. Separators for liquid electrolyte Li-ion batteries can be classified into porous polymeric membranes, nonwoven mats, and composite Separators. Porous membranes are most commonly used due to their relatively low processing cost and good mechanical properties. Although not widely used in Li-ion batteries, nonwoven mats have the potential for low cost and thermally stable Separators. Recent composite Separators have attracted much attention, however, as they offer excellent thermal stability and wettability by the nonaqueous electrolyte. The present paper (1) presents an overview of separator characterization techniques, (2) reviews existing technologies for producing different types of Separators, and (3) discusses directions for future investigation. Research into separator fabrication techniques and chemical modifications, coupled with the numerical modeling, should lead to further improvements in the performance and abuse tolerance as well as cost reduction of Li-ion batteries.
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.
Lixin Yang - One of the best experts on this subject based on the ideXlab platform.
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Numerical Investigation on a New Type of Two-Stage Steam Separator in Pressurized Water Reactors
Energy Procedia, 2017Co-Authors: Zihao Tian, Lixin YangAbstract:Abstract Stream separator is a fundamental part of pressurized water reactor in order to guarantee the steam humidity produced by steam generator is below 0.25%. It’s essential for the safe and economical operation of nuclear power plant. Most two-stage steams separator consist of swirl-vane Separators and corrugated-plate Separators. But the volume and flow resistance of corrugated-plate Separators are great and re-entrainment phenomenon happens occurs easily when the velocity of flow is high. In this paper, a new type of two-stage steam separator was presented that the second stage separator was designed as a swirl-vane type instead of traditional corrugated-plate type in order to improve the separation efficiency of steam and gas in pressurized water reactors. A computational fluid dynamics (CFD) method was used to investigate the effect of this new structure on the separation efficiency and pressure drop. The flow field details of air-gas flow and the variation trend with the Reynold number and air-gas phase flux were obtained. The influencing factors such as the cylinder diameter, the distance between two stage Separators and the bending angle of swirling vanes were investigated. The value of separation efficiency was high at the longer diameter, distance and greater bending angle. The separation efficiency of second stage separator experienced an increasing trend when the water flux increase and the first stage separation decrease. A good agreement was obtained between simulation results and engineering test results.
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.
