Pine Pollen-Derived Activated Carbon for High-Performance Supercapacitor Electrodes: A Comparative Study of KOH and CuCl 2 Activation

Carbon-containing materials are vital for supercapacitor electrodes. Activated porous carbons are especially attractive due to their high surface area, conductivity, and porous structure, making them ideal for double-layer supercapacitors. Recently, researchers have turned to biological materials like bacteria, algae, fungi, and pollen to create porous carbon structures. Among these, pine pollen stands out for its abundance and ease of collection. This study focused on converting pine pollen into porous carbon using hydrothermal carbonization in water, followed by activation with different agents. The carbonized pollen was activated with KOH and CuCl ₂ at various ratios to form nanostructured porous carbons. Scanning electron microscope images showed that activation with KOH and CuCl ₂ partially altered the pollen morphology. The sample with a 1:2 pollen-to-KOH ratio had the highest surface area at 2030.32 m²/g. To evaluate their electrochemical performance, supercapacitor electrodes were created using two types of activated carbons. The specific capacitance of KOH-activated carbon (KAC) was 230 F/g, while CuCl ₂ -activated carbon (CuAC) showed 175.9 F/g, both at 5 A/g. After 5000 charge-discharge cycles, KAC retained 76% of its capacitance, and CuAC retained 93%. These results demonstrate pine pollen's potential as a precursor for high-performance porous carbons.