Designing Comb-Chain Crosslinker-Based Solid Polymer Electrolytes for Additive-Free All-Solid-State Lithium Metal Batteries

Developing solid polymer electrolytes (SPEs) is a promising approach to realize practical dendrite-free lithium metal batteries (LMBs). Tuning the nanoscale polymer network chemsitry is of critical importance for SPE design. In this work, we took lessons from the rubber chemistry and developed a series of comb-chain crosslinker-based SPEs (ConSPEs) using a preformed polymer as the multifunctional crosslinker. The high-functionality crosslinker increased the connectivity of nanosized cross-linked domains, which led to a robust network with dramatically improved toughness and superior lithium dendrite resistance even at a current density of 2 mA cm-2. The uniform and flexile network also dramatically improved the anodic stability to over 5.3 V versus Li/Li+. Additive-free, all-solid-state LMBs with the ConSPE showed high discharge capacity and stable cycling up to 10 C rate, and could be stably cycled at 25 °C. Our results demonstrated that ConSPEs are promising for high-performance and dendrite-free LMBs.