Electrochemical performance of reduced graphyne oxide and biomass-derived activated carbon composite for energy storage devices

Electrochemical double-layer capacitors (EDLCs) have attracted significant attention because their fast charging/discharging performance, excellent cycle life, and high-power density. Despite these advantages, EDLC still need to overcome their low capacity and improve their fast charging/discharging performance. To achieve high-performance EDLCs, the development of novel active materials with excellent properties is crucial. In this study, reduced-graphyne oxide (rGYO) and biomass-derived activated tofu-based carbon (A-tofu) composites, which exhibited superior performance compared to commercial activated carbon (YP50F), were combined through composite formation (rGYO@A-tofu) and applied as active materials for EDLCs. The rGYO@A-tofu electrode demonstrated excellent performance at both low and high current densities, with a specific capacitance of 280.4 F g^-1 at a current density of 0.2 A g^-1 and 156 F g^-1 at a current density of 20 A g^-1. Additionally, the rGYO@A-tofu electrode exhibits excellent capacitance retention (95.4% after 5,000 cycles at a current density of 10 A g^-1). The excellent performance of the rGYO@A-tofu electrode was attributed to the synergistic effect of the connection between the biomass-derived activated tofu-based carbons through rGYO and the improved electron mobility owing to the unique alkynyl groups in rGYO. Therefore, rGYO@A-tofu is a promising active material for use in EDLCs.