Photocharge‐Enhanced Capacitive Response of a Supercapacitor

Abstract A radiation‐sensitive, binder‐free, solid‐state supercapacitor (SC) has been fabricated based on spinel nickel cobaltite (NiCo 2 O 4 )/zinc oxide nanorods (ZnO NRs) as the electrode material. The enhanced surface area of the electrochemical electrode not only provides a noteworthy enhancement in electrochemical activity, but also the generated photoinduced excitons significantly contribute to achieving outstanding electrode conductivity. This finding reveals that the generated photocharges during UV irradiation participate largely in converting radiation energy into electrochemical energy through redox reactions that allow the specific capacitance to double when compared to an absence of UV radiation. Moreover, the novel SC demonstrates an outstanding cyclic stability of 98.5 and 97 % capacitance retention after 2000 cycles of charge–discharge in the absence and presence of UV irradiation, respectively. Thus, this study opens up an avenue for the direct utilization of radiation‐sensitive nanomaterials for electrochemical energy storage and demonstrates a strong potential for the fabrication of advanced SCs.