Anion-regulated solid polymer electrolyte enhances the stable deposition of lithium ion for lithium metal batteries

Abstract The adoption of lithium metal anodes, which are ideal for constructing batteries with high specific energy, is limited by dendrite growth and poor cycle performance. Herein, an anion-regulated solid polymer electrolyte based on in-situ-polymerized poly(ethylene glycol ether acrylate) is prepared for dendrite-free lithium metal batteries. According to the space-charge theory, the growth of lithium dendrites is effectively inhibited by the improved electric field of solid polymer electrolyte on the lithium anode side. And this solid system achieves a lithium transfer number of 0.63, excellent ionic conduction on 2.16 × 10 −5  S cm −1  at room temperature), a wide electrochemical stable window (4.8 V vs. Li + /Li) and excellent cycle performance. The flexible batteries (LiFePO 4 cathode/solid polymer electrolyte/lithium metal) are assembled to power a light-emitting diode at room temperature. We highlight the anion regulated polymer solid electrolyte, which shows great potential for solid lithium metal batteries and flexible batteries.