Supercapacitor application of a three-dimensional carbon sphere–intercalated porous carbon fabricated using a hard template and a biomass material

A combination strategy involving the use of a hard template and a biomass material was employed to prepare carbon sphere–intercalated porous carbon with a hierarchical structure for application in a high-performance supercapacitor. The preparation of the microporous activated carbon first involved the carbonization and chemical activation of golden shower tree seeds and potassium ferrate. The activated carbon was then modulated through anchoring with hard-template-derived mesoporous carbon spheres (HMCSs). The obtained porous carbon had a high surface area (1446 m2 g−1), a high pore volume (1.29 cm3 g−1), a low proportion of micropores (Smicro/SBET = 8.4 %), and mesopores, indicating the successful development of carbon sphere–intercalated heterostructural architectures. It displayed a specific capacitance (154 F g−1 at a scan rate of 5 mV s−1) in 6 M KOH aqueous electrolyte. Considering the pore structure, this study employed the LiPF6 electrolyte, which has a larger ionic size, in assembling a supercapacitor. The device exhibited excellent capacitive properties, with a peak energy density of 19.16 mWh cm−3 and a peak power density of 3.25 W cm−3.