Ultrafine bismuth sulfide-based solid-state electrochemical capacitor in full wave AC-signal rectification application

Supercapacitors, also known as electrochemical capacitors, have been widely investigated as advanced energy-storage devices owing to their high-power density, moderately high energy density and long cycle life, while their integration into electronic circuits has emerged as a fascinating area of research that combines efficient energy storage with practical circuit-level functionality. In this study, organic molecule (pyrazole) stabilized bismuth sulfide nanoparticles were synthesized using a complexation mediated route, and an electrode fabricated based on these nanoparticles exhibited a specific capacity (S _C) of 211 C g^-1 at a scan rate of 5 mV s^-1. The asymmetric capacitor made with bismuth sulfide as an anode and MXene as a cathode exhibited a maximum S _C value of 43 C g^-1 at a current density (C _D) of 0.8 A g^-1. The device delivered a maximum energy density (E _D) of 17.9 Wh kg^-1 with a corresponding power density (P _D) of 2.6 kW kg^-1 at 0.8 A g^-1, while increasing the C _D to 2.9 A g^-1 resulted in an E _D of 11.3 Wh kg^-1 and a corresponding P _D of 5.2 kW kg^-1. The as-fabricated bismuth sulfide-based electrochemical capacitor was integrated into a full-wave bridge rectifier circuit for efficient conversion of alternating current (AC) into direct current (DC), demonstrating its potential for practical energy-storage and electronic circuit applications.