Synergistic 3D Porous PTFE Membrane Skeleton and 1D HNTs Integration for High-Performance All-Solid-State Polymer Electrolytes

Incorporation of one-dimensional inorganic nanofillers into the poly(ethylene oxide)–based solid polymer electrolyte (PEO-SPEs) matrix can substantially enhance its ionic conductivity and overall electrochemical performance. However, the intrinsically low melting point of PEO and the pronounced hygroscopicity of lithium salts impart insufficient mechanical robustness to PEO-SPEs, undermining their compatibility with high-loading cathodes, reducing discharge capacities, and compromising cycling stability. To address these limitations, we fabricated a supported all-solid-state composite polymer electrolyte (SACPEs) via high-temperature, high-pressure infiltration of a molten multicomponent PEO–SPEs into a three-dimensional porous polymer membrane skeleton. The 3D skeleton provides exceptional mechanical strength, effectively suppressing lithium-dendrite growth at the electrode/electrolyte interface, while its interconnected porous network enables rapid Li+ transport. Furthermore, orientation forces during melt infiltration uniformly align the one-dimensional inorganic nanofillers along the melt-flow direction within the skeleton, thereby shortening Li+ migration pathways. Electrochemical and mechanical evaluation of the resulting SACPEs demonstrates a high ionic conductivity of 2.35 × 10–4 S cm–1, a Li+ transference number of 0.649, a tensile strength of 26.7 MPa, a high initial discharge specific capacity (181 mAh g–1), and excellent long-term cycling performance (capacity retention of 80.66% after 200 cycles at 0.1 C). These comprehensive performance metrics confirm that the SACPE meets the rigorous electrochemical and mechanical requirements for all-solid-state polymer electrolytes in next-generation lithium metal batteries.