A recent study investigated the modification of biochar to enhance its electrochemical performance as an electrode material for supercapacitors. By treating pine sawdust-derived biochar with nitric acid (HNO3) and hydrogen peroxide (H2O2), researchers improved its pore structure and functional group composition, which are critical for energy storage.

The modifications optimized the biochar’s microstructure, with the nitric acid-treated sample (NPCBC-45) exhibiting a high micropore concentration at 0.92 nm and a mesoporosity of 33%. Similarly, the hydrogen peroxide-modified biochar (HPCBC-20) achieved 0.90 nm micropores and 65% mesoporosity. These changes significantly enhanced the biochar’s specific capacitance—NPCBC-45 reached 338.88 F g⁻¹, a 137% improvement compared to unmodified biochar, while HPCBC-20 achieved 165 F g⁻¹, marking a 15.6% increase.

The study also demonstrated the stability of the modified biochar in electrochemical applications. After 2000 cycles, NPCBC-45 retained 94% of its capacitance, showcasing its durability. The high concentration of oxygen-containing functional groups introduced during modification, such as carbonyl (C=O) and ether (C-O-C), contributed to the biochar’s enhanced pseudocapacitance.

This research highlights a sustainable approach to transforming sawdust waste into high-performance materials for clean energy storage, advancing the potential of biochar in supercapacitor technology. It provides a foundation for further exploration of biochar modification techniques to optimize energy storage solutions.