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 LiCoO₂/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⁻¹), 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.

中文翻译：

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循环碳酸盐基聚合物电解质增强4.45 V LiCoO2 / Li金属电池诱导的聚合物增强SEI层

锂（Li）金属电池（LMB）由于能量密度高而正在复兴。然而，它们仍然遭受由固体电解质相间（SEI）层的连续裂化引起的不可控制的Li枝晶和粉化的问题。为了解决这些问题，在电化学调节过程中自发构建坚固的聚合物增强SEI层可以是一种简单而有效的解决方案。本文中，通过原位聚合方法提出了一种坚固的环状碳酸酯氨基甲酸酯甲基丙烯酸酯均聚物作为聚合物基质，其中环状碳酸酯单元可以在循环过程中参与构建稳定的聚合物集成SEI层。研究中的凝胶聚合物电解质（GPE）组装LiCoO ₂/ Li金属电池具有出色的循环能力，在0.5 C（1 C = 180 mAh g ^-1）下200次循环后的容量保持率为92％，明显超过了使用液体电解质的电池。值得注意的是，在接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可实现机械增强的SEI层，从而与锂阳极具有出色的相容性。原位形成的聚合物增强SEI层为开发与Li金属阳极兼容的耐高压GPEs向高能LMBs提供了出色的策略。