Metal (Co/Zn) Acetate-Modified Porous Carbon Derived from Peanut Shells as a Superior Supercapacitor Electrode Material

Biomass-derived activated carbon has garnered significant attention due to its notable porosity, viability, and adequacy. This study employed peanut shells as the carbon source to produce porous carbon through hydrothermal carbonization (HTC) with or without activating reagents (Co and Zn Acetates) for evaluation as a supercapacitor electrode material. The dried precursor powder, with or without an activating agent, underwent hydrothermal treatment at 200 °C for 7 h, followed by carbonization at 400 °C for 3 h in an open atmosphere furnace. The sample treated with Zn acetate (PS-ZnA) exhibits the highest BET-specific surface area of 273.2 m 2 g −1 . Raman spectra depict distinct D and G bands at approximately 1343 and 1580 cm −1 , respectively. The electrochemical performance was assessed using a three-electrode setup with 1 M H 2 SO 4 electrolyte. The PS-ZnA demonstrates a specific capacitance of 105.5 F g −1 , surpassing that of the PS-CoA. The PS-ZnA also exhibits energy and power densities of 8.62 Wh kg −1 and 381 W kg −1 , respectively. Furthermore, the PS-ZnA illustrates an 88.2% retention rate after 5000 cycles at 10 A g −1 , along with a low R s value of 2.82 Ω, indicating favorable electrical conductivity. These findings strongly suggest that Zn acetate-treated porous carbon synthesized using HTC serves as an exceptional electrode material for supercapacitors.