Wood-Structured Electrolyte for Ultra-Stable Zinc-Ion Batteries Under High Discharge Conditions

Aqueous zinc-ion batteries (AZIBs) operate stably at low depth of discharge (DOD) but suffer severe Zn²⁺ transport imbalance, hydrogen evolution, and plating/stripping at high DOD (> 70%). Here, we present a radial wood-based hierarchical heterogeneous interconnected structure (HHIS) electrolyte. HHIS is without low-tortuosity channels, but during cycling, Zn²⁺ predominantly migrates along laterally oriented vessels, fibers, and rays via pit coordination, ensuring uniform deposition. Leveraging these synergistic effects, HHIS stabilizes the Zn anode under high current, enabling > 9000 h of cycling and > 3300 h at 83.1% DOD, surpassing previous reports. This work directly converts wood into a high-performance electrolyte and establishes a HHIS design strategy for addressing high-DOD instability in AZIBs and advancing electrolyte commercialization.