Preparation of micropores-rich carbon materials for high energy density aqueous supercapacitors using bio-templates and green N-doping strategy

Abstract

The construction of N/O co-doped porous carbon using natural bio-templates is essential to improve the energy density of aqueous supercapacitors. This study proposes a new strategy to prepare natural N/O co-doped bamboo-derived porous carbon using shrimp shells as multifunctional bio-templates. Shrimp shells exhibit multiple roles: proteins and chitin as a heteroatom source and CaCO₃ as a sacrificial hard template. The results show that the best carbon material (BC-SP-1) simultaneously displays a gravimetric capacitance of 311.45F/g and a volumetric capacitance of 283.98F/cm³. The aqueous symmetric supercapacitor (SS-BC-SP-1) and the Zn-ion hybrid supercapacitor (ZHSC-BC-SP-1) exhibit excellent cycling stability. In addition, ZHSC-BC-SP-1 displays a high energy density of 97.44 Wh/kg. The density functional theory (DFT) calculations indicate that the existence of N/O functional groups significantly enhances the adsorption of Zn-ion on carbon materials, especially pyrrolic N, quinone, and ether groups. In this study, the effects of heteroatom functional groups on the electrochemical properties of carbon materials are analyzed from multiple perspectives using experiments and simulations. This work utilizes shrimp shells as green bio-templates to optimize carbon material structure and enrich heteroatom, laying the foundation for the green synthesis of high-performance biomass-derived carbon electrode materials.