The conversion of renewable biomass resources into advanced electrode materials through green, simple, and economical methods has become an important research direction in energy storage. In this study, Fe-decorated N/S-codoped porous carbon nanospheres have been successfully fabricated from cuttlefish ink through Fe2(SO4)3-assisted hydrothermal carbonization coupled with heat treatment. The effects of Fe2(SO4)3 dosage on the structure, chemical composition, and capacitive property of carbon nanospheres were investigated. Herein, environmentally friendly Fe2(SO4)3 plays a multifunctional role as the graphitization catalyst, dopant, and morphology-regulating agent. Benefitting from the moderate graphitization degree, great heteroatom content and hierarchical porous structure, the prepared carbon nanospheres exhibit high specific capacitance (311.9 F g-1 at a current density of 0.5 A g-1), good rate capability (19.1% decrease in specific capacitance as current density increases from 0.5 to 10 A g-1), and ideal cycling stability (94.3% capacitance retention after 5000 cycles). In addition, the symmetric supercapacitor assembled with the carbon nanosphere electrodes achieves an energy density of 9.7 Wh kg-1 at a power density of 0.25 kW kg-1 and maintains 91.3% capacitance after 10,000 cycles. The desirable electrochemical performance of cuttlefish ink-derived carbon nanosphere material makes it a potential electrode candidate for supercapacitors.
Keywords: Biomass; Carbon nanosphere; Cuttlefish ink; Iron sulfate; Supercapacitor.
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