Pore Microstructure Impacts on Lithium Ion Transport and Rate Capability of Thick Sintered Electrodes
Pore Microstructure Impacts on Lithium Ion Transport and Rate Capability of Thick Sintered Electrodes
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DOI：
10.1149/1945-7111/ac0bf6
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发表时间：
2021-06
影响因子：
3.9
通讯作者：
Ziyang Nie;Rohan Parai;C. Cai;C. Michaelis;J. LaManna;D. Hussey;D. Jacobson;Dipankar Ghosh;Gary M. Koenig
中科院分区：
文献类型：
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作者：
Ziyang Nie;Rohan Parai;C. Cai;C. Michaelis;J. LaManna;D. Hussey;D. Jacobson;Dipankar Ghosh;Gary M. Koenig
增加电极厚度是提高锂离子电池单元的能量密度的一种途径。然而，在电解质相中通过厚电极的多孔微结构的受限Li+传输限制了用这些高能电池实现高电流密度和充电/放电速率的能力。在这项工作中，寻求减少运输限制的加工路线。所使用的电极仅由一起烧结成多孔颗粒的活性材料组成。对于其中一个电极，在使用冰模板以提供定向孔隙度和在处理期间使用牺牲颗粒以匹配几何密度而没有孔对准之间进行比较。冰模板化的电极在较高的循环速率下保持大得多的放电容量，这归因于由加工提供的改善的传输性质。使用所评估的电池的电化学模型和含有冰模板化颗粒的电池的中子成像来进一步表征电极。结果表明，通过对电极微结构进行模板化，可以显著改善电化学电池的性能，其中速率限制步骤包括电池中的离子传输限制。
Increasing electrode thickness is one route to improve the energy density of lithium-ion battery cells. However, restricted Li+ transport in the electrolyte phase through the porous microstructure of thick electrodes limits the ability to achieve high current densities and rates of charge/discharge with these high energy cells. In this work, processing routes to mitigate transport restrictions were pursued. The electrodes used were comprised of only active material sintered together into a porous pellet. For one of the electrodes, comparisons were done between using ice-templating to provide directional porosity and using sacrificial particles during processing to match the geometric density without pore alignment. The ice-templated electrodes retained much greater discharge capacity at higher rates of cycling, which was attributed to improved transport properties provided by the processing. The electrodes were further characterized using an electrochemical model of the cells evaluated and neutron imaging of a cell containing the ice-templated pellet. The results indicate that significant improvements can be made to electrochemical cell properties via templating the electrode microstructure for situations where the rate limiting step includes ion transport limitations in the cell.