Preparation and properties of chestnut shell-based biochar electrode material for high-performance symmetrical supercapacitor

High performance supercapacitor electrode material (CC 700-Zn) was successfully prepared by using chestnut shell as carbon source (CC) and ZnCl2 activation after carbonization of CC at 700℃. The morphology and performance of CC700-Zn electrode materials were tested. It was found that CC700-Zn had a 3D channel network structure with a specific surface area of 813.9m²/g, and the network structure formed by mesopores and micropores provided a channel for electronic transmission. In a three-electrode system, CC700-Zn showed a high specific capacitance of 506F/g at a current density of 1A/g and outstanding cycling stability of 91% capacitance retention after 10000 cycles. In a two-electrode system, a symmetrical capacitor was assembled with CC700-Zn. The symmetric capacitor had a specific capacitance of 118F/g at 1A/g, the scan rate of CV can be increased to 220mV/s, and the potential window width was 0~1.6V. When the power density was 900W/kg, the energy density was 53.1W·h/kg. When the power density was increased to 27000W/kg, the energy density can still be maintained at 27W·h/kg. The above results indicated that it was feasible to prepare symmetrical supercapacitor electrode materials using chestnut shell as carbon source. © 2021, Chemical Industry Press Co., Ltd. All right reserved.