Formulation of N-doped carbon with meso/microporous structure for supercapacitors through biotemplates

Abstract

Developing carbon materials based on biomass for supercapacitors has enormous potential to address the pressing issues of resource waste and environmental contamination. Nevertheless, biomass-based supercapacitors confront two major challenges: limited pore structure and the absence of surface functional groups. In this research, urea (U) acted as the nitrogen dopant, eggshells (ES) as the biotemplate, and eucalyptus leaves (EL) as the primary raw material to produce N-doped hierarchical porous carbon via co-pyrolysis. The results demonstrated that ES0.25U1 possesses a large specific surface area (SSA) of 1742.59 m2.g−1 and an excellent meso/microporous structure. Furthermore, significant quantities of oxygen (25.22 %) and nitrogen (3.18 %) were detected in ES0.25U1. The ES0.25U1 exhibits a specific capacitance (Cs) of 349F.g−1 (0.5 A.g−1), and the symmetric supercapacitor constructed from it possesses an energy density of 7.57 Wh.kg−1 while maintaining a capacity retention rate of 92.57 % and a Coulombic efficiency of 98.76 % after 10,000 charging/discharging cycles. Moreover, a comprehensive exploration into the N-doping mechanism and the underlying principles governing the formation of meso/microporous architectures through the utilization of bio-templates has been undertaken. This work provides a robust theoretical framework for the rational design and fabrication of high-value bio-derived carbonaceous materials utilizing combinatorial strategies of biotemplates and heteroatom doping.