A universal magnetic alignment strategy for composite solid-state electrolytes with vertically aligned high-ionic-conductivity pathways

Abstract

The low ionic conductivity of polymer-based solid-state electrolytes limits their application. Conventional enhancements by adding inorganic fillers typically requires material-specific modifications or complex processing. Herein, we report a universal magnetic alignment strategy using field-responsive “guide” nanorods to construct vertically aligned transport channels (VATC) of Li+ in poly(ethyleneoxide) (PEO)-based composite electrolytes. Via magneto-mechanical coupling, these “guide” nanorods spatially organize non-magnetic Li₇La₃Zr₂O₁₂ (LLZO) fillers without direct magnetic modification. The resulting composite with low-tortuosity pathways achieves an ionic conductivity of 1.2 × 10⁻⁴ S cm⁻¹ at 30 °C, doubling that of the randomly dispersed counterpart. In LiFePO₄‖Li all-solid-state cells, it simultaneously delivers improved rate capability and cycling stability. This work demonstrates a simple, scalable, and material-agnostic route to high-performance solid-state electrolytes, promising for next-generation energy storage.