Solar-driven induced photoelectron remember effect involved in core–shell NiCo2S4@Ni3V2O8 composite electrode with superior electrochemical energy storage for asymmetric supercapacitor

Abstract

Photo-assisted supercapacitor systems offer a compelling approach to effectively harnessing both solar and electrical energy. In this study, the core–shell heterostructure NiCo₂S₄@Ni₃V₂O₈ (NCS@NVO) was successfully synthesized for the development of photosensitive supercapacitor electrodes. NCS@NVO demonstrated a pronounced photoelectron memory effect under illumination, attributed to the solar-driven contributions of both NCS and NVO, as photon absorption facilitated electron-hole pair separation and transport. Compared to the specific capacitance in the dark (2292F g⁻¹ at 1 A g⁻¹), the capacitance of the NCS@NVO composite electrode increased dramatically to 3025F g⁻¹ when exposed to light. Moreover, the capacitance retention rate remained remarkably high at 99.83 % after 10,000 cycles at 20 A g⁻¹. In addition, the NCS@NVO hybrid supercapacitor achieved an outstanding energy density of 63.56 W h kg⁻¹ under illumination, alongside a power density of 789.84 W kg⁻¹. This study thoroughly investigated the solar-induced photoelectron memory effect in the NCS@NVO composite electrode for asymmetric supercapacitors, paving the way for the design of high-performance photosensitive nano-electrodes in advanced electrochemical energy storage applications.