Bougainvillea flower-biochar for zinc-ion hybrid super-capacitor: role of chemical activator

The recent surge in developing highly porous cathodes (HPC) derived from waste biomass sources for zinc-ion hybrid super-capacitors (ZIHSCs) has sparked significant interest. This study uses an inexpensive precursor technique to explore a cost-effective approach by converting bougainvillea flowers (BG) into biochar (BG-Biochar). Biochar that experienced chemical activation treatment has significantly increased porosity and surface functional group. The phosphoric acid (H₃PO₄) treated biochar (BG-H₃PO₄) demonstrates superior performance compared to both potassium hydroxide (KOH) treated biochar (BG-KOH) and untreated BG-Biochar in ZIHSCs. The ZIHSC device, based on BG-H₃PO₄, achieves the maximum specific capacitance and specific capacity at 0.1 A g^− 1 current density. Furthermore, this work contributes to understanding biochar-based cathodes, shedding light on the influence of different activation treatments on porosity and surface characteristics. The findings emphasize the potential of bougainvillea flower-derived biochar as a promising material for energy storage applications, particularly in ZIHSCs. The notable electrochemical performance of BG-H₃PO₄ highlights the significance of tailored chemical activation in optimizing biochar properties for enhanced super-capacitor applications.