Biomass-Derived Hard Carbon Anodes from Setaria Viridis for Na-Ion Batteries

Abstract

Biomass-derived hard carbon has gradually become an important component of sodium-ion batteries’ anodes. In this work, Setaria viridis, a widely distributed plant, was employed as a precursor to synthesize hard carbon anodes for sodium-ion batteries. However, the hard carbon derived from raw precursors contains substantial impurities, which limit the performance of the obtained hard carbon. With different chemical etching processes, the content of impurities in the resultants was reduced to varying degrees. The optimized hard carbon anode delivered a reversible capacity of 198 mAh g−1 at a current density of 0.04 A g−1. This work shows the effects of impurities, especially the Si-based matter, on the formation of microstructure and electrochemical performance of the regulated hard carbon, which broadens the application of the biomass-derived materials. This work also provides a strategy for processing impurity-rich biomass precursors to develop hard carbon anodes for sodium-ion batteries (SIBs).