Sustainable balsa-derived polyaniline/activated carbon composites for high-performance asymmetric supercapacitors

Lightweight balsa wood, with its intrinsic hierarchical porosity, was employed as a sustainable precursor to prepare phosphoric acid-activated carbon (PNOAC), which was subsequently modified with polyaniline (PANI) via an in-situ polymerization strategy to construct high-performance supercapacitor electrodes. The heteroatom-doped carbon framework (N/O/P) provides high conductivity, abundant redox-active sites, and interconnected porosity, while the conformal PANI coating contributes additional pseudocapacitance and structural stability. By optimizing the aniline-to‑carbon ratio, the [email protected] composite delivered a high specific capacitance of 539 F g −1 at 0.5 A g −1 and maintained 72.6 % retention at 10 A g −1 . Electrochemical impedance spectroscopy revealed a low charge-transfer resistance (0.218 Ω), and density functional theory (DFT) calculations confirmed favorable proton and anion adsorption, as well as enhanced electronic density near the Fermi level, elucidating the accelerated redox kinetics. When assembled into an asymmetric supercapacitor with PNOAC as the negative electrode, the device achieved an energy density of 14.08 Wh kg −1 at 845 W kg −1 and retained 9.39 Wh kg −1 at 8450 W kg −1 , with 87.3 % capacitance retention after 1000 cycles. Moreover, the device successfully powered a light-emitting diode, demonstrating its practical applicability. This work provides a scalable and sustainable strategy for integrating biomass-derived conductive carbons with pseudocapacitive polymers, offering significant potential for next-generation high-energy supercapacitors.