In situ generated polymer electrolyte coating-based Janus interfaces for long-life LAGP-based NMC811/Li metal batteries

NASCION-type Li+ conductor Li1.5Al0.5Ge1.5P3O12 (LAGP) has been well considered as a promising solid-state electrolyte for solid-state lithium mental batteries (SSLMBs) by virtue of several strengths (e.g., high ionic conductivities, good stability under ambient conditions, and wide electrochemical stability windows). However, there are rare reports concerning the utilization of LAGP-based solid electrolytes in the high-voltage LiNi0.8Mn0.1Co0.1O2 (NMC811)/Li metal cell. This can be ascribed to the fact that the mechanochemically stable interface toward Li metal anodes and compatible interface close to NMC811 cathodes cannot be simultaneously achieved. To address this, herein, a LAGP-type solid electrolyte with in situ generated polymer electrolyte coating-based Janus interfaces is developed. The as-developed solid electrolyte is prepared by coating LAGP with in situ crosslinked polymethyl methacrylate and poly(cyclic carbonate urethane methacrylate)-based polymer electrolytes toward lithium anode and NMC811 cathode, respectively. It is demonstrated that the as-developed solid electrolyte can achieve both compatible electrode–electrolyte interphases. As a result, this solid electrolyte endows 4.3 V and 4.5 V-class NMC811/Li batteries with superior cycling stability. Our work provides a good paradigm to address the interfacial issues confronting solid state electrolyte chemistries.