Flexible Zn‐ion Electrochromic Batteries with Multiple‐color Variations

Abstract Electrochromic batteries as emerging smart energy devices are highly sought after owing to their real‐time energy monitoring through visual color conversion. However, their large‐scale applicability is hindered by insufficient capacity, inadequate cycling stability, and limited color variation. Herein, a flexible Zn‐ion electrochromic battery (ZIEB) was assembled with sodium vanadate (VO Na+ ) cathode, ion‐redistributing hydrogel electrolyte, and Zn anode to address these challenges. The electrolyte contains anchored −SO 3 − and ‐NH 3 + , which facilitates ionic transportation and prevents Zn dendrite formation by promoting orientated Zn 2+ deposition on the Zn (002) surface. The ZIEB exhibits a continuous reversible color transition, ranging from fully charged orange to mid‐charged brown and drained green. It also demonstrates a high specific capacity of 302.4 mAh ⋅ g −1 at 0.05 A ⋅ g −1 with a capacity retention of 96.3 % after 500 cycles at 3 A ⋅ g −1 . Additionally, the ZIEB maintains stable energy output even under bending, rolling, knotting, and twisting. This work paves a new strategy for the design of smart energy devices in wearable electronics.