Effect of vacuum-carbonization treatment of soft carbon anodes derived from coal-based mesophase pitch for lithium-ion batteries

Development of new power anode material with both high capacity and high-rate capability for lithium-ion batteries is highly desired. In this paper, a novel soft carbon anode for rechargeable lithium-ion batteries was developed using coal-based mesophase pitch. The structures of the materials were characterized by X-ray diffraction (XRD), Raman, N2 adsorption–desorption, Scanning Electron Microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The electrochemical characteristics of the new anode material were investigated. It was found that the soft carbon anode from coal-based mesophase pitch carbonized under vacuum conditions can deliver higher energy density and higher rate capability compared to soft carbon carbonized under a nitrogen atmosphere. The enhanced electrochemical properties are attributed to smaller nanocrystallites, more porosity, defects and carbon species of the resulting anode material.