Solvation-Regulated PVDF Solid Polymer Electrolytes Enabled by Borates for Dendrite-Resistant Lithium Metal Batteries

Despite their mechanical robustness and high-voltage stability, poly(vinylidene fluoride) (PVDF) solid polymer electrolytes are hindered by sluggish Li + transport, stemming from anion-dominated conduction and residual solvent-induced interfacial degradation. This study addresses these issues by introducing zinc borate (ZB) as a filler into the PVDF electrolyte and preparing the composite electrolyte PVZB, thereby reconstructing the lithium-ion solvation structure and stabilizing the electrode interface, elevating the Li + transference number to 0.49, and boosting room-temperature ionic conductivity to 3.3 × 10 −4 S cm −1 . Crucially, a rich inorganic solid electrolyte interphase enables stable cycling of Li/PVZB/Li cells for 3000 h at 0.1 mA cm −2 . NCM811/PVZB/Li cells deliver 78.5% capacity retention after 400 cycles at 4.3 V with excellent Coulombic efficiency (99.2%). Graphical A dual-enhancement strategy for PVDF electrolytes is achieved by zinc borate, which simultaneously reconstructs the Li + solvation structure and drives the formation of an inorganic-rich SEI.