Electrochemical Behaviors, Charge Storage, Efficiency Capacity and Cycling Stability of Biochar –Based Electrodes for Supercapacitors

This paper compared biochar electrodes made from yam stalk (YM), groundnut husk (GN), and their composite (HB) for supercapacitor applications. Electrochemical performance was evaluated using electrochemical tests (such as Cyclic Voltammetry (CV), Galvanostatic Charge-Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS). The HB composite electrode was found to be the most capacitive with a high specific capacitance of 225 F/g, energy density of 31.3 Wh/kg, and power density of about 250 W/kg. EIS results revealed low internal resistance (R? = 0.50 ?, Rct = 3.50 ?), confirming excellent conductivity and efficient ion diffusion. The enhanced electrode performance of the HB electrode was because of its optimized porous structure and the presence of synergistic interaction between biochar components. In summary, the research demonstrates the possibility of agricultural waste-based biochar to be used as low-cost eco-friendly and high-performance supercapacitor electrodes.