Preparation and electrochemical study of cottonseed shell porous carbon/carbon nanospheres composites
Yue Xiaoming, Song Guohao, Ye Mei, Chen Zihua
（School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116,  China）
Abstract：It is of great significance for the application of composite materials based on two biomasses as electrode materials in supercapacitors. In this paper, cottonseed shell/ carbon nanospheres composites (GPCs@TQ-1) were prepared by hydrothermal treatment of cottonseed shell pyrolytic carbon and glucose, and then one-step activation with KOH. The samples were characterized by SEM, TEM, Raman spectroscopy, XRD, N₂ adsorption and desorption. The electrochemical properties were investigated by constant current charge and discharge, electrochemical impedance spectroscopy and cyclic voltammetry. The microstructure and electrochemical properties of the carbon composites were studied by means of structure characterization and electrochemical tests. The results showed that the specific surface area of GPCs@TQ-1 was 2281.39 m²/g when the glucose content was 10 g, and the surface morphology of glucose nanospheres was obvious. Under the current density of 0.5 A/g, the specific capacitance can reach 308.8 F/g; when the current density was increased to 5 A/g, the specific capacitance was 263.9 F/g, which showed excellent ratio performance. After 5000 charge and discharge tests, the capacitance still remained at 90.93%. In addition, when assembled into a symmetrical supercapacitor, the output power reached 1246 W/kg, and the energy density was 4.5 W·h/kg.

Keywords: Biochar; Carbon nanospheres; Composite materials; Supercapacitors

Biochar; Carbon nanospheres; Composite materials; Supercapacitors