Synthesis of honeycomb-like hierarchical porous carbon via molten salt pyrolysis in a novel sequencing integration system for high-performance supercapacitors

Abstract

Abstract The main objective of this study is to develop a new sequencing integration process combining carbonization and activation procedure. Simultaneously, high-surface area honeycomb-like porous carbons are produced from furfural residues through a molten salt method at a low impregnation ratio for high performance supercapacitors. The experimental results show that the porous carbon has a large surface area over 2494 m2 g−1 and a total pore volume of 1.51 cm3 g−1 at a low impregnation ratio of 0.8. Additionally, only 120 s is sufficient for soaking char with molten salt. The porous carbon-based electrode exhibits higher capacitance of 210.2 F g−1 with 96.3% capacity retention after 10, 000 cycles at 5 A g−1 in 6 M KOH electrolyte. More importantly, the supercapacitor based on FS-60-120-800-1 electrode exhibits a high energy density of 52.6 Wh kg−1 at a power density of 251.0 W kg−1. Compared with conventional chemical activation method, porous carbons with high surface area and excellent pore structure are produced at a shorter time, and less activation dosage by this new molten salt-potassium hydroxide activation method. The remarkable honeycomb-like porous carbon can be used as a promising electrode material for high performance supercapacitor in energy storage applications.