Integrated oxidation and bio-functionalization of graphite using natural bioactive latex for high-performance supercapacitor electrodes

A sustainable one-pot approach is presented for the direct bio-functionalization of graphite using Calotropis gigantea (CG) latex as a natural multifunctional reagent. In contrast to conventional multi-step graphene oxide functionalization routes, this strategy integrates oxidation and surface modification into a single process. The phytochemical constituents of CG latex introduce hydroxyl (–OH), amine (–NH₂), carbonyl (–C=O), and sulfur-containing functionalities, yielding a poly-functionalized graphene oxide (Poly-fGO) with enriched surface chemistry. Comprehensive characterization by PXRD, FE-SEM, XPS, Raman and FTIR, analyses confirms successful functionalization, expanded interlayer spacing, and improved textural properties. The increased d-spacing and heteroatom incorporation facilitate enhanced ion diffusion and charge-transfer kinetics. Electrochemical investigations reveal superior capacitive behavior, delivering a high specific capacitance of 252 F g−1 at 1 A g−1 with excellent cycling stability over 5000 charge–discharge cycles. The improved performance is attributed to pseudocapacitive contributions from multifunctional surface groups. This green and scalable synthesis route offers a promising platform for advanced graphene-based materials in high-performance energy storage applications.