Anchoring Side Chains to Carbonate Groups for Reviving Stable Polycarbonate-Based Solid-State Lithium Metal Batteries

Polycarbonate-based electrolytes are ideal electrolytes for solid-state lithium metal batteries (LMBs) due to their wider electrochemical windows and considerable ionic conductivities compared with conventional solid polymer electrolytes. However, polycarbonates encounter severe interfacial side reactions with lithium metal, leading to the interfacial degradation of polymers. Herein, a spontaneously formed restricted conformation is designed via the in situ anchoring of side chains to suppress the interfacial degradation of polycarbonate-based electrolytes. The restricted conformation enables the side chains to shield and protect the degradable ester bonds of cyclic carbonates, suppressing contact and interfacial degradation between polycarbonates and lithium metal anodes. As a proof of concept, the protected polycarbonate-based electrolyte demonstrates a stable cycling capability of the Li/Li cell beyond 1000 h at a current density of 0.5 mA cm^-2, and the assembled LiNi_0.8Co_0.1Mn_0.1O₂/Li pouch cell also achieves similar improvement in cycling performance. This work indicates that the strategy of constructing restricted conformations via anchoring side chains is a feasible avenue for fabricating highly stable polycarbonate-based solid-state LMBs.