Boosting Zinc-Ion Hybrid Supercapacitor Performance with Basil-Derived Activated Carbon: Impact of Substrates and Mass Loading on Electrochemical Efficiency

This study explores the use of basil-derived activated carbon (BC) as an electrode material for zinc-ion hybrid supercapacitors (ZIHSCs) in a coin cell configuration. BC is synthesized through straightforward pyrolysis and deposited on various conductive substrates, including graphite foil (Gr), carbon cloth (CC), titanium foil (Ti), copper foil (Cu), and nickel foam (Ni). Among these, graphite foil (BC-Gr) demonstrates the most favorable electrochemical performance. The BC-Gr electrode achieves a notable specific capacitance of 220 F/g, an energy density of 78 W h/kg, and exhibits exceptional cycling stability, maintaining nearly 100% capacity retention over 10,000 cycles. The study further examines the impact of BC mass loadings (3, 5, 8, 10, and 16 mg) on the electrochemical performance of BC-Gr-based ZIHSCs. Results reveal that lower mass loading enhances performance due to reduced internal resistance and improved ion transport, with the 3 mg electrode achieving the highest specific capacitance and optimal overall performance. The device also exhibits robust rate capability across <i>C</i>-rates ranging from 0.1 to 5 C. This research underscores the potential of BC-Gr as cost-effective and high-performing electrode material for energy storage. The findings contribute to the advancement of scalable, environmentally friendly ZIHSC technologies, providing a sustainable solution for energy storage applications.