Inorganic perovskite photo-assisted supercapacitor for single device energy harvesting and storage applications

Halide-perovskite having excellent electronic, ionic, optoelectronic and optoionic properties have been found suitable for both energy harvesting and energy storage devices. Herein, we exploit these properties to fabricate a photo-assisted supercapacitor serving the dual functions of energy harvesting and electrochemical energy storage in a single device. The device utilized stable inorganic Cu₃Bi₂I₉ perovskite material in fabricating a Cu-perovskite photoactive electrode. A novel HPvA gel electrolyte was synthesized and sandwiched between two Cu-perovskite photoactive electrodes, to obtain a Cu-perovskite photo-assisted supercapacitor. The HPvA gel electrolyte was characterized by fourier-transfrom infrared spectroscopy (FTIR), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The Cu-perovskite photoactive electrode was characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). We characterized the electrochemical and photo-electrochemical energy storage performance of the Cu-perovskite photo-assisted supercapacitor by cyclic voltammetry (CV) and EIS. The device recorded 127 % energy density augmentation, at a scan rate of 0.01 V/s. The Cu-perovskite photo-assisted supercapacitor retained 93.8 % of its initial capacitance, after 10,000 charge-discharge cycles.