Self-assembly mediated 3D Architectural Multiple-heteroatoms Doped Porous Carbons for Supercapacitors

Abstract

To enhance ion transport and diffusion efficiency within electrolytes, it is essential to synthesize carbon-based electrode materials with high specific surface area, a narrow pore-size distribution, a well-developed microporous architecture, and heteroatom doping. Herein, a novel strategy of self-assembling chitosan, sodium lignosulfonate, and potassium oxalate in an aqueous system as a scaffold precursor is presented to address this issue. In this approach, electrostatic interactions between the sulfonic acid groups of sodium lignosulfonate and the protonated amino groups of chitosan, together with extensive hydrogen bonding, induce the self-assembly into a stable three-dimensional cross-linked network. Additionally, the carboxyl groups of potassium oxalate undergo ionic cross-linking with the protonated amino groups of chitosan, thereby facilitating the uniform distribution of the pore-forming agent throughout the scaffold. Chitosan's amino groups and sodium lignosulfonate's sulfonic acid groups serve as intrinsic nitrogen and sulfur precursors for in situ heteroatom doping. The resulting carbon material exhibits a high specific surface area of 1,388 m2 g−1 and a concentrated micropore size of 0.80 nm. This electrode also features a specific capacitance of 235 F g−1 at 0.5 A g−1, maintaining 71.3% of this capacity at 20 A g−¹ and retaining 97% after 10,000 cycles. This synthetic strategy capitalizes on synergistic interactions among biomass-derived precursors. It addresses the challenge of regulating pore structure in biomass-derived carbon materials, offering a green, energy-efficient route to fabricate capacitive carbon materials with both high capacity and superior rate capability.