High‐Performance Aqueous Zinc‐Organic Battery with a Photo‐Responsive Covalent Organic Framework Cathode

Abstract

AbstractCovalent organic framework (COF) materials, known for their robust porous character, sustainability, and abundance, have great potential as cathodes for aqueous Zn‐ion batteries (ZIBs). However, their application is hindered by low reversible capacity and discharge voltage. Herein, a donor–acceptor configuration COF (NT‐COF) is utilized as the cathode for ZIBs. The cell exhibits a high discharge voltage plateau of ≈1.4 V and a discharge capacity of 214 mAh g−1 at 0.2 A g−1 when utilizing the Mn2+ electrolyte additive in the ZnSO4 electrolyte. A synergistic combination mechanism is proposed, involving the deposition/dissolution reactions of Zn4SO4(OH)6·4H2O and the co‐(de)insertion reactions of H+ and SO42− in NT‐COF. Meanwhile, the NT‐COF with a donor–acceptor configuration facilitates efficient generation and separation of electron‐hole pairs upon light exposure, thereby enhancing electrochemical reactions within the battery. This leads to a reduction in charging voltage and internal overvoltage, ultimately minimizing electricity consumption. Under ambient weather conditions, the cell exhibits an average discharge capacity of 430 mAh g−1 on sunny days and maintains consistent cycling stability for a duration of 200 cycles (≈19 days) at 0.2 A g−1. This research inspires the advancement of Zn‐organic batteries for high‐energy‐density aqueous electrochemical energy storage systems or photo‐electrochemical batteries.