The solid–electrolyte interphase (SEI) is pivotal in stabilizing lithium metal anodes for rechargeable batteries. However, the SEI is constantly reforming and consuming electrolyte with cycling. The rational design of a stable SEI is plagued by the failure to control its structure and stability. Here we report a molecular-level SEI design using a reactive polymer composite, which effectively suppresses electrolyte consumption in the formation and maintenance of the SEI. The SEI layer consists of a polymeric lithium salt, lithium fluoride nanoparticles and graphene oxide sheets, as evidenced by cryo-transmission electron microscopy, atomic force microscopy and surface-sensitive spectroscopies. This structure is different from that of a conventional electrolyte-derived SEI and has excellent passivation properties, homogeneity and mechanical strength. The use of the polymer–inorganic SEI enables high-efficiency Li deposition and stable cycling of 4 V Li|LiNi_0.5Co_0.2Mn_0.3O₂ cells under lean electrolyte, limited Li excess and high capacity conditions. The same approach was also applied to design stable SEI layers for sodium and zinc anodes.

固体电解质中间相（SEI）在稳定可充电电池的锂金属阳极方面至关重要。但是，SEI经常通过循环来重整和消耗电解质。稳定的SEI的合理设计受到无法控制其结构和稳定性的困扰。在这里，我们报告了一种使用反应性聚合物复合材料的分子级SEI设计，该设计可有效抑制SEI形成和维持过程中的电解质消耗。SEI层由聚合物锂盐，氟化锂纳米颗粒和氧化石墨烯片组成，这由低温透射电子显微镜，原子力显微镜和表面敏感光谱学证明。该结构不同于常规的电解质衍生的SEI，并且具有优异的钝化性能，均质性和机械强度。贫电解质，有限的锂过量和高容量条件下的_0.5 Co _0.2 Mn _0.3 O ₂电池。同样的方法也被应用于为钠和锌阳极设计稳定的SEI层。