Optimization of fluorinated orthoformate based electrolytes for practical high-voltage lithium metal batteries
Optimization of fluorinated orthoformate based electrolytes for practical high-voltage lithium metal batteries
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DOI：
10.1016/j.ensm.2020.08.035
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发表时间：
2021-01-01
影响因子：
20.4
通讯作者：
Zhang, Ji-Guang
中科院分区：
文献类型：
--
作者：
Cao, Xia;Zou, Lianfeng;Zhang, Ji-Guang
近年来，响应于对高能量密度电池的日益增长的需求，锂（Li）金属电池（LMB）已经恢复活力。然而，Li金属阳极（LMA）的不稳定性仍然是限制这些电池的大规模应用的关键障碍。这项工作优化了三（2，2，2-三氟乙基）原甲酸酯（TFEO）为基础的电解质，并揭示了背后的基本机制，对LMA和阴极的稳定性。还发现，由于在循环过程中盐的消耗，电解质的优化组合物对电池中使用的电解质量的量敏感。优化的TFEO基电解质可产生高效的固体电解质界面和阴极电解质界面，可防止连续的电极/电解质副反应，并在非常具有挑战性的条件下（4.2 mAh cm-2阴极负载，50 µm Li和3 g Ah-1的贫电解质）显著延长采用NMC 811阴极的LMB的循环寿命。在这项工作中发现的设计原则提供了指导电解质的进一步发展，高能量密度LMB的稳定运行。
Lithium (Li) metal batteries (LMBs) have been revitalized in recent years in response to the increasing demand for high energy density batteries. However, the instability of Li metal anodes (LMAs) is still a critical barrier that limits large scale applications of these batteries. This work optimizes tris (2, 2, 2-trifluoroethyl) orthoformate (TFEO) based electrolytes and reveals the fundamental mechanisms behind their stability towards both LMA and cathodes. It is also found that the optimized composition of the electrolytes is sensitive to the amount of the electrolyte amount used in the batteries due to the consumption of the salt during the cycling process. The optimized TFEO based electrolytes create a highly effective solid electrolyte interphase and cathode electrolyte interphase, that prevent continuous electrode/electrolyte side reactions and significantly prolongs the cycle life of LMBs with a NMC811 cathode under very challenging conditions (4.2 mAh cm-2 cathode loading, 50 µm Li and lean electrolyte of 3 g Ah-1). The design principles discovered in this work provides guidance for further development of electrolytes for the stable operation of high energy density LMBs.