Tailoring electrolyte coordination structure for high-rate polymer-based solid-state batteries

Abstract

Solid-state batteries (SSBs) offer intrinsic safety and superior energy density, promising next-generation energy storage. Polymer-based solid-state electrolytes (SSEs) stand out for their facile processing and low cost. However, the development of SSBs is impeded by the intrinsically low ionic conductivity of polymer electrolytes at room temperature, alongside limitations in their inherent electrochemical stability and thermal resilience. Here, we propose a novel solvation-tailoring strategy by embedding 3D continuously interconnected zirconium-based metal–organic framework (MOF808) nanofillers into a polyvinylidene fluoride–hexafluoropropylene (PVDF–HFP) matrix (designated as PLM-3). This design leverages the strong adsorption of MOF808 for solvent molecules (−0.521 eV) to thermodynamically displace them from the Li⁺ solvation sheath, replacing them with anions and forming an anion-enriched coordination configuration. This precisely tailored solvation environment, quantified by a surge in anion-aggregate (AGG) species, significantly enhances Li⁺ transport kinetics by reducing Li⁺ desolvation energy by 15.8% (−5.29 vs. −6.28 eV), thereby endowing the resultant electrolyte with exceptional rate performance. When coupled with a high voltage single-crystal NCM83 (SC-NCM83) cathode, the PLM-3 cell delivers exceptional rate capability (219.5 mAh g⁻¹ at 0.1C; 182.8 mAh g⁻¹ at 5C) while maintaining 93.73% capacity retention after 200 cycles at 1C with a 4.3 V cutoff voltage. This solvation-tailoring strategy thus redefines the rate limits of polymer-based SSBs and paves the way for the development of high-power, high-energy, and industrially viable SSBs.