Biomass Self-Nitrogen Doped Mesoporous Carbon Electrode for Supercapacitors

Doping and surface modification of porous carbon materials derived from biomass are part of the research hotspots that promote high performance and low cost of electrode materials for supercapacitors, owing to advantage of tunable unique structure of renewable biomass. Nitrogen-rich spirulina extract impregnated castor shell was used to effectively regulate and modify the surface morphology of biomass carbon by KOH activation and high-temperature calcination. The prepared porous carbon exhibits nitrogen-rich micro-mesoporous carbon with unique interconnected network structure and higher specific surface area (1527 m2 g-1) after the high temperature treatment for supercapacitor electrode. The nitrogen-rich organic functional groups derived from extract of spirulina improve interaction of KOH and castor shells responsible for formation of unique interconnected micro-mesoporous structure. The as-prepared nitrogen doped micro-mesoporous carbon contributes to enhance charge transfer, and to decrease mass transfer resistance of supercapacitor electrode. A good electrochemical performance with high specific capacitance of 333 F g-1 at 1 A g-1 was obtained. The charge/discharge cycling behavior shows only loss of 0.3 % of total capacity after 10,000 cycles at 10 A g-1. The two-electrode configuration of assembled CSSK material displayed a remarkable energy density of 10 Wh kg-1 at a power density of 600 W kg-1 and good cycling behavior (after 10000 cycles 91.7 % retention of specific capacitance). Thus, strategy of the extract mediated synthesis is facile and effective to improve the performance of porous carbon for promising candidates as low-cost electrode materials for supercapacitors.