Structural regulation of carbon materials through hydrothermal mixing of biomass and its application in supercapacitors

Using low-cost biomass to effectively prepare porous carbon with appropriate structural properties for supercapacitor electrodes materials remains significant. Herein, we report an efficient method to prepare hierarchical porous carbon using a mixing biomass carbon precursor by sugarcane bagasse and hydroxyapatite from beef bone powder, following with hydrothermal carbonization and KOH activation. The resulting carbon material presents a high specific surface area of 3103.14 m2 g−1, a large pore volume of 1.91 cm3 g−1, and appropriate porosity. Benefiting from these features, the as-assembled symmetrical supercapacitor exhibits high specific capacitance of 397.9 F g−1 (at 0.5 A g−1) in 6 M KOH electrolyte. Moreover, in 1 M Na₂SO₄ electrolyte, it also exhibits high energy density of 23.2 Wh kg−1 at a power density of 874 W kg−1. The enhanced capacitive performance demonstrates that the mixing biomass carbon precursor is desirable to synthesize porous carbons for energy storage.