Effects of the oxidation treatment with K2FeO4 on the physical properties and electrochemical performance of a natural graphite as electrode material for lithium ion batteries

A natural graphite was modified by the solution oxidation with K2FeO4, and the physicochemical properties of the oxidated graphite were investigated by various physical techniques and electrochemical methods. The results of SEM, EDAX and Raman spectra showed that after the oxidation treatment with K2FeO4, some mesoscopic pores/channels and thin oxide layer are introduced in the surface of graphite. The results of electrochemical experiments indicated that the oxidated graphite displays much larger reversible capacity, better electrochemical-cycling stability and much lower electrochemical and diffusion polarizations than pristine natural graphite. The maximum reversible capacities of pristine natural graphite and the oxidated graphite are 244 and 363 mAh/g, respectively.