Stimuli-Triggered Diffusion Dynamics in Single-Junction Electrode for Enhanced Supercapacitor Performance: Insights...

Study of external triggers add new chemistry to energy storage research by virtue of controlling diffusion and charge transfer dynamics. Herein, we have chosen a model system, Ag₂S-BiVO₄ (Ag₂S-BVO), for examining the diffusion dynamics upon light illumination using electrochemical and carrier relaxation studies. Favorable band alignments in the single-junction electrode lead to optimized carrier movement across the interfaces, developing a partial positive charge on the electrode, thereby enhancing the mass-transport of electrolyte ions toward the active electrode for efficient charge storage. Synergistic coupling across the heterojunction provides a high areal capacity of 338 mF cm^-2 at 0.5 mA cm^-2 under light illumination by facilitating the dominant diffusion characteristics within system. In addition, the Ag₂S-BVO-based asymmetric supercapacitor exhibits an areal energy density of 32 mWh cm^-2 @ 700 mW cm^-2 under illumination. This study provides a strategy to tune the capacitive and diffusion contributions for high-performance light-sensitive supercapacitor devices.