Multi-Stage Collaborative Design of Hierarchical Twisted Hydrogel Electrolytes for Aqueous Zinc-Ion Batteries with High Capacity, Ultralong Stability, and Mechanical Robustness

Abstract

Aqueous zinc-ion batteries (AZIBs) are promising energy storage systems due to their high theoretical capacity, intrinsic safety, and potentially high cycling stability. However, their practical application is hindered by sluggish Zn-ion transfer, parasitic side reactions, and dendrite growth, leading to suboptimal capacity and limited cycle lifespan. Herein, we report a bioinspired design of hierarchical twisted hydrogel electrolytes (HTHEs) by establishing a multi-stage collaborative regulation pathway to address these challenges. The HTHE exhibits a high Zn2+ transference number of 0.9 and a wide electrochemical stability window of 2.61 V, effectively suppressing dendrite formation and enhancing Zn2+ deposition along the Zn (002) plane. Symmetric cells assembled with the HTHE demonstrate exceptional cycling stability across a wide range of current densities, while pouch cells achieve an ultra-long cycle life of nearly 10000 cycles with a high specific capacity of >100 mAh g-1 and 80% capacity retention. Notably, these pouch cells display outstanding flexibility and impact resistance, remaining fully operational under folding and even withstanding extreme mechanical stresses, such as those even crack walnuts. The multi-stage collaborative regulation pathway in the design of high-performance flexible AZIB electrolytes enhances their potential for next-generation energy storage applications.