Oxygen evolution reaction enhancing electrochemical performance of V-doped Ni(OH)2 for aqueous asymmetric supercapacitors

[Display omitted] •A V-doped Ni(OH)2 electrode is proposed for cathode for ASCs.•The OER during CV activation greatly enhances the electrochemical performance.•The V doping facilitates the OER during CV activation.•The electrochemical activation mechanism is elucidated. Large capacitance and stable cycling performance of electrodes are critical for the success of aqueous asymmetric supercapacitors. In this study, we propose a novel synergistic strategy involving V doping and electrochemical activation to optimize the electrochemical performance of Ni(OH)2. Our results demonstrate that the oxygen evolution reaction (OER), occurring during the activation process, is crucial for performance enhancement, with V doping significantly facilitating this reaction. The optimized V-Ni(OH)2-A0 electrode exhibits a high specific capacitance of 3.9 F cm−2 at 10 mA cm−2 and excellent long-term cycling stability, retaining 88 % of its initial capacitance after 10,000 cycles at a current density of 30 mA cm−2. Furthermore, the aqueous asymmetric supercapacitor, consisting of V-Ni(OH)2-A0 and carbon cloth, achieves an energy density of 0.50 mWh cm−2 with a power density of 10.92 mW cm−2, with exceptional cyclic performance, maintaining 96 % of its capacitance after 30,000 cycles at a current density of 25 mA cm−2. These findings underscore the potential of leveraging the OER to significantly enhance the electrochemical performance of Ni(OH)2 based electrodes.