通过在胶体 SiO2 纳米颗粒表面包覆多孔壳层提高聚乙烯隔膜的热稳定性和锂离子电导率。
Enhanced thermal stability and lithium ion conductivity of polyethylene separator by coating colloidal SiO nanoparticles with porous shell.
机构信息
Research Centre of Nanoscience and Nanotechnology, Shanghai University, Shanghai 200444, China.
Research Centre of Nanoscience and Nanotechnology, Shanghai University, Shanghai 200444, China.
出版信息
J Colloid Interface Sci. 2019 Oct 15;554:29-38. doi: 10.1016/j.jcis.2019.06.102. Epub 2019 Jul 1.
Electric vehicles have very strict requirements for lithium ion batteries (LIBs). However, the commercial polyethylene (PE) separators cannot meet the demands of high safety and electrochemical performance for LIBs. This work aims to enhance the electrochemical and safety performance of LIBs by coating the separator with multifunctional particles. First, the colloidal SiO nanoparticles were etched by LiOH to form porous shell and lithium silicate (LSO) species simultaneously. Then, the SiO nanoparticles with porous shell were coated on PE separator by dip-coating method in the presence of binder. The experiment results indicate that SiO nanoparticles with porous shell can endow PE separator excellent thermal stability (thermal shrinkage is almost 0% at 150 ℃ for 30 min) and electrochemical properties (improved ionic conductivity and Li ion transference number). Moreover, the Li/LiCoO cell employing the PE separator coated by SiO with porous shell exhibits the best cycle life and C-rate performance. The discharge capacity retention of the cell assembled with LSO-SiO@PE separator increase from 69% (cells assembled with pristine PE separator) to 86% after 100 cycles at 0.2C.
电动汽车对锂离子电池（LIB）有非常严格的要求。然而，商用的聚乙烯（PE）隔膜不能满足 LIB 对高安全性和电化学性能的要求。本工作旨在通过在隔膜上涂覆多功能颗粒来提高 LIB 的电化学和安全性能。首先，通过 LiOH 刻蚀胶体 SiO 纳米颗粒，同时形成多孔壳和硅酸锂（LSO）物质。然后，在存在粘结剂的情况下，通过浸涂法将具有多孔壳的 SiO 纳米颗粒涂覆在 PE 隔膜上。实验结果表明，具有多孔壳的 SiO 纳米颗粒可以赋予 PE 隔膜优异的热稳定性（在 150°C 下 30 分钟热收缩几乎为 0%）和电化学性能（提高离子电导率和锂离子迁移数）。此外，采用涂覆有具有多孔壳的 SiO 的 PE 隔膜的 Li/LiCoO 电池表现出最佳的循环寿命和倍率性能。在 0.2C 下循环 100 次后，与采用原始 PE 隔膜组装的电池相比，采用 LSO-SiO@PE 隔膜组装的电池的放电容量保持率从 69%提高到 86%。
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