An Intelligent “Solid–Liquid” Hybrid Electrolyte for High-Voltage and Dendrite-Free Lithium Metal Batteries

In situ polymerized electrolytes significantly enhance the interfacial stability of lithium metal batteries (LMBs). Typically, in situ polymerized 1,3-dioxolane (PDOL) shows good compatibility with Li metal yet still suffers from low room temperature (RT) ionic conductivity and a narrow electrochemical stability window (ESW). Commercial zeolite molecular sieves are widely used in traditional industries and can also inhibit the DOL monomer polymerization. Therefore, a unique solid–liquid hybrid electrolyte (PDOL-Z) is designed by coating zeolite particles on the cathode side of the PP separator, which greatly improves the Li-ion transport capacity and efficiency. The RT ionic conductivity is already close to that of the liquid electrolyte (9.45 × 10–4 S cm–1), and the transference number (tLi+) reaches an impressive 0.95. Desolvation occurs when the liquid electrolyte passes through the nanopore channels, which greatly reduces the oxidative decomposition of the solvent molecules on the high-voltage cathode side. Consequently, the ESW of the PDOL-Z is improved to 4.67 V. Additionally, the Li anode side consists of an in situ polymerized electrolyte with sufficient mechanical strength, which effectively prevents the formation of lithium dendrites. Owing to the aforementioned advantages, the Li/PDOL-Z/LiCoO2 battery demonstrates outstanding long-cycle stability at 4.3 V, with 80% capacity retention after 400 cycles. This research presents a novel design for the practical implementation of high-voltage and dendrite-free LMBs.