Hu Rongxiang, Qiu Huayu, Zhang Huanrui, Wang Peng, Du Xiaofan, Ma Jun, Wu Tianyuan, Lu Chenglong, Zhou Xinhong, Cui Guanglei
College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, P. R. China.
Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, P. R. China.
Small. 2020 Apr;16(13):e1907163. doi: 10.1002/smll.201907163. Epub 2020 Mar 4.
Lithium (Li) metal batteries (LMBs) are enjoying a renaissance due to the high energy densities. However, they still suffer from the problem of uncontrollable Li dendrite and pulverization caused by continuous cracking of solid electrolyte interphase (SEI) layers. To address these issues, developing spontaneously built robust polymer-reinforced SEI layers during electrochemical conditioning can be a simple yet effective solution. Herein, a robust homopolymer of cyclic carbonate urethane methacrylate is presented as the polymer matrix through an in situ polymerization method, in which cyclic carbonate units can participate in building a stable polymer-integrated SEI layer during cycling. The as-investigated gel polymer electrolyte (GPE) assembled LiCoO /Li metal batteries exhibit a fantastic cyclability with a capacity retention of 92% after 200 cycles at 0.5 C (1 C = 180 mAh g ), evidently exceeding that of the counterpart using liquid electrolytes. It is noted that the anionic ring-opening polymerization of the cyclic carbonate units on the polymer close to the Li metal anodes enables a mechanically reinforced SEI layer, thus rendering excellent compatibility with Li anodes. The in situ formed polymer-reinforced SEI layers afford a splendid strategy for developing high voltage resistant GPEs compatible with Li metal anodes toward high energy LMBs.
锂（Li）金属电池（LMBs）因其高能量密度而正在复兴。然而，它们仍然面临着锂枝晶不可控以及由固体电解质界面（SEI）层持续开裂导致的粉化问题。为了解决这些问题，在电化学条件下开发自发形成的坚固聚合物增强SEI层可能是一种简单而有效的解决方案。在此，通过原位聚合法提出了一种由环状碳酸酯聚氨酯甲基丙烯酸酯组成的坚固均聚物作为聚合物基体，其中环状碳酸酯单元在循环过程中可以参与构建稳定的聚合物集成SEI层。所研究的凝胶聚合物电解质（GPE）组装的LiCoO₂/Li金属电池表现出出色的循环性能，在0.5 C（1 C = 180 mAh g⁻¹）下循环200次后容量保持率为92%，明显超过使用液体电解质的同类电池。值得注意的是，靠近锂金属阳极的聚合物上环状碳酸酯单元的阴离子开环聚合能够形成机械增强的SEI层，从而与锂阳极具有优异的兼容性。原位形成的聚合物增强SEI层为开发与锂金属阳极兼容的耐高压GPEs以实现高能量LMBs提供了一个出色的策略。
