Hierarchical porous chitosan-based carbon co-doped with boron and nitrogen for high-performance supercapacitors

The properties of biomass porous carbon materials are important for supercapacitor energy storage devices. This study presents a novel B and N co-doped hierarchical porous carbon (BPC) synthesized from chitosan via a facile K 2 CO 3 activation strategy. The chitosan precursor was pretreated to enhance its suitability for carbonization, resulting in a highly conductive carbon skeleton with a developed hierarchical porous structure and a specific surface area of 507 m 2 /g. The effects of B and N element doping on the surface morphology and electrochemical properties of BPC were investigated. The electrochemical properties of the materials were characterized using cyclic voltammetry, galvanostatic charge-discharge tests, and impedance spectroscopy. The optimized sample (CBP-1) demonstrated exceptional electrochemical performance: achieving a specific capacitance of 527 F g −1 at 4.5 A g −1 and exhibiting outstanding cycling stability with 84% capacitance retention after 10,000 charge/discharge cycles at 10 A g −1 . Electrochemical impedance spectroscopy confirmed superior interfacial properties with a low equivalent series resistance (R s ) of 1.19 Ω. Chitosan distinguishes itself from other biomass materials by its rich -NH 2 groups, which allow for effective nitrogen self-doping. This intrinsic advantage translates into enhanced conductivity and wettability for BPC, contributing to its improved electrochemical performance. B and N co-doping creates structural defects that facilitate electrolyte penetration and shorten ion diffusion paths while providing pseudo capacitance. Chitosan-based B and N co-doped hierarchical porous carbon is a promising capacitor-modified electrode material with potential applications in energy storage.