Asymmetric Polymer Electrolyte Constructed by Metal–Organic Framework for Solid‐State, Dendrite‐Free Lithium Metal Battery

Abstract Solid‐state polymer electrolytes (SPEs) with flexibility, easy processability, and low cost have been regarded as promising alternatives for conventional liquid electrolytes in next‐generation high‐safety lithium metal batteries. However, SPEs generally suffer poor strength to block Li dendrite growth during the charge/discharge process, which severely limits their wide practical applications. Here, a rational design of 3D cross‐linked network asymmetric SPE modified with a metal–organic framework (MOF) layer on one side is proposed and prepared through an in‐situ polymerization process. In such unique asymmetric SPEs, the nanoscale MOF layer acts as a shield that effectively suppresses the growth of Li dendrites and regulates the uniform Li + transport, and the polymer electrolyte can be scattered in the whole cell to endow the smooth transmission of Li + . As a result, the asymmetric SPE exhibits high ionic conductivity, wide electrochemical window, high thermal stability and safety, which endows the Li/Li symmetrical cell with outstanding cyclic stability (operate well over 800 h at a current density of 0.1 mA cm −2 for the capacity of 0.1 mAh cm −2 ).