The structural changes and sodium storage in the carbon phase of cobalt sulfide/carbon composites

Abstract

Transition metal sulfide/carbon composites are fascinating and widely studied anode materials with superior sodium storage capacity. However, these researches mainly focus on the structural variation of cobalt sulfides. In this study, we turn the attention to the structural variation of the carbon phase in classical cobalt sulfide/carbon composites. The defect densities and surface oxygen functional groups were increased in the carbon phase in Co₄S₃/carbon composites. The abundant sodium storage active sites and enlarged interlayer spacing in the carbon phase improved cycling and rate performances. The investigation of the chemical and microstructural surface changes in carbon substrates provides a more comprehensive understanding of the high performance of transition metal sulfide/carbon composites.