Mechanochemistry induced various surface microstructural transformation in hard/soft carbons for sodium storage

Hard carbon (HC) and soft carbon (SC) are two classic anode materials for sodium-ion batteries. Various sodium storage behaviors are always induced by the different order degree in the graphitic layers of two carbon materials. Herein, the mechanochemical effects on the structures and electrochemical performances of HC/SC were studied. Comparably, the short-range ordered structure in SC transforms into a more disordered structure, and the degree of change is more pronounced than HC, thus indicating a higher increase of defects and more transformation of oxygen groups directionally. Notably, some new micropore structure were formed on the disordered surface of HC, which are absent from the SC. The performance of SC treated by mechanochemistry is improved by 23.2 %, higher than HC (19.4 %). The structural evolution of the classical HC and SC modified by mechanochemical effect provides a novel and comprehensive insight on carbon-based anode materials in energy storage field.