Performance study of high energy storage supercapacitor from waste corn husk biomass electrode materials

Waste biomass carbon materials are used as green and environmentally friendly electrode materials for supercapacitors (SCs) have great development prospects, therefore, miscellaneous elements-rich and recycled renewable porous carbon materials have important applications value in the field of energy storage device. In this paper, waste corn husk as biomass precursor to prepare corn husk porous carbon (CHPC) using two steps of high-temperature carbonization and KOH activation. The CHPC-2 optimized by KOH shows a specific surface area (SSA) of 1103 m2 g−1 and a total pore volume of 0.83 cm3 g−1, achieving a high specific capacitance of 413.4 F g−1 at 0.5 A g−1. After 10,000 cycles, only 4.17 % of the capacitance was lost. In a two-electrode system with 1 M Na2SO4 as the electrolyte, CHPC-2//CHPC-2 exhibits a specific capacitance of 333 F g−1 at a wide voltage window of 0–1.8 V, and energy density of 37.46 Wh Kg−1 when power density is 450 W kg−1, which possesses the capacitance retention rate of 85.16 % after 5000 cycles. The assembled symmetrical SCs contain capacitance of 308.79 F g−1, and 21.02 Wh kg−1 under a power density of 350 W kg−1 in PVA/KOH gel electrolyte. Consequently, CHPC materials provide a scientific and reasonable research idea for the development of SCs with inexpensive, non-polluting, and high energy density.