Natural biomass-derived porous carbons from buckwheat hulls used as anode for lithium-ion batteries

Abstract

Abstract Biomass-derived porous carbon has provided new ideas for the preparation of new energy materials due to its cost-effectiveness and abundance, promoting its application in lithium-ion batteries. In this paper, porous carbon was prepared by a simple and economical carbonization process with buckwheat hulls as raw material and CaCl2 as an activator to improve the electrochemical performance of carbon materials. When the mass ratio of buckwheat hull and CaCl2 is 1:2.5, the porous carbon materials with a specific surface area of 351.018\xa0m2\xa0g−1 has a specific capacity of 715.0 mAh g−1 (about 1.9 times the specific capacity of the graphite anode) after 150\xa0cycles at 0.2C and 444.8 mAh g−1 after 500\xa0cycles at 5C. These results confirm that the porous structure of porous carbon materials contributes to the rapid transport of lithium ions in the electrolyte and electrode material. In addition, this study shows that the use of waste biomass, i.e., buckwheat hulls, overcomes the deficiency of low capacity of graphite anode and provides a new option for the preparation of high-performance negative electrode material for LIBs.