From Surface Vermiculation to Performance Leap: A Scalable Strategy for Achieving High-Stability Aqueous Hydrogen Proton Batteries

This work introduces a novel oxygen-assisted vermiculation treatment, marking the first application of the vermiculation concept in optimizing the Cu1.92S cathode surface, significantly enhancing the performance of aqueous hydrogen proton batteries (AHPBs). Due to their nonstoichiometric structure and strong electron–ion migration capabilities, Cu1.92S cathodes were facing challenges such as tip discharge, surface dissolution and collapse, and self-discharge. To address these issues, a 30-day aging treatment in an oxygen-rich environment was employed to induce surface vermiculation. The findings reveal three major improvements postvermiculation: (1) the elimination of tip discharge effects, reducing hydrogen evolution reaction (HER); (2) the enhancement of the work function, suppressing electron escape and lowering self-discharge; (3) the strengthening of hydrogen proton adsorption, significantly boosting charge storage capacity, reaction kinetics, and cycling stability. After the vermiculation treatment, the specific capacity of Cu1.92S increased from 506.5 to 561.2 mAh g–1, the cycling life extended from 1600 to 2400 cycles, and charge–discharge efficiency improved. This study provides a simple and scalable post-treatment method for the surface modification of copper sulfide-based cathodes, laying the foundation for the development of high-performance and long-life aqueous energy storage systems.