Flexible Solid-State Electrolyte with Aligned Nanostructures Derived from Wood

Solid-state Li-batteries (SSLiBs) with solid-state electrolytes (SSEs) can potentially block Li dendrite penetration, enabling the application of metallic lithium anodes to achieve high energy density with improved safety. The ion transport behavior and ionic conductivity in Li-ion batteries is significantly influenced by the tortuosity of the electrode and electrolyte materials. Low-tortuosity structures with straight ion pathways are highly desirable yet very difficult to achieve in solid-state ion conductors. Templating from wood, for the first time, we developed a highly conductive garnet framework with multiscale aligned mesostructure through a scalable, top-down approach. Ion-conductive poly(ethylene oxide) (PEO) was incorporated into the mesoporous, wood-templated aligned garnet nanostructure, resulting in a flexible solid-state composite electrolyte. The synergistic integration of the aligned garnet with soft, mechanically robust polymer results in both a high ionic conductivity (1.8 × 10–4 S/cm at room temperature) and good mechanical flexibility. This work provides a new direction for developing low-tortuosity, fast ion conductors inspired by nature.