Experimental evaluation of a supercapacitor-biased bipolar junction transistor switch for battery charging charging system
摘要
Activated carbon derived from feed grain food waste (FW) was synthesized and evaluated as an eco-friendly electrode material for high-performance supercapacitors. The preparation process involved chemical carbonization using 9 M sulfuric acid at 120o C for 48 h, followed by potassium hydroxide activation through microwave pyrolysis, consistent with recent biomass activation methods. Among the investigated samples, the optimized FWAC 1:3 (KOH: FWAC = 1:3) exhibited a moderate specific surface area of 290 m² g⁻¹ with a favorable pore size distribution, contributing to enhanced electrochemical performance, similar to previous studies on food-waste-derived carbon electrodes. In a three-electrode configuration, the electrode delivered a specific capacitance of 220 F g⁻¹ at a current density of 0.5 A g⁻¹, while the symmetric two-electrode device maintained a specific capacitance of 190 F g⁻¹. The electrode also demonstrated excellent cycling stability with minimal capacitance degradation over 10,000 charge–discharge cycles, highlighting the long-term durability reported in other biomass-derived systems. Furthermore, a laboratory-scale symmetric supercapacitor was fabricated and integrated into a bipolar junction transistor (BJT)-biased power supply for a smartphone battery charging circuit to validate its practical applicability. The results highlight the potential of food-waste-derived activated carbon as a sustainable and cost-effective alternative to conventional electrode materials for supercapacitor-based energy storage and electronic applications.