Preparation and electrochemical study of cottonseed shell porous carbon/carbon nanospheres composites

Based on the morphology of carbon microspheres and stable capacitance characteristic of dual material composite, it has great research significance in the preparation of electrode materials for supercapacitor. In this work, cottonseed shell/carbon nanospheres composite (CSPC@G) was prepared with cottonseed shell and glucose through hydrothermal carbonization and KOH activation. The structural features and electrochemical properties of the composites have been studied using physical representation and electrochemical tests. CSPC@G has the large specific surface area of 2281.39 m2 g−1 with obvious nanospheres on the surface of the material. In a three-electrode system with a 6 M KOH electrolyte, CSPC@G offers a high specific capacitance of 308.8 F g−1 at 0.5 A g−1 and the specific capacitance is reduced by only 18.2% even at 20 A g−1. The cyclic stability is maintained at 92.9% after 5000 cycles of charge and discharge. A symmetric double-layer capacitive device assembled with CSPC@G exhibits an energy density of 4.5 Wh kg−1 at 1246 W kg−1. This paper provides a new approach to prepare electrode materials for supercapacitors from cottonseed shell and glucose, and to broaden the applications of cottonseed shell.