Abstract

Here we demonstrate for the first time that an anode material for lithium ion batteries can be satisfactorily prepared by a green method. By selecting benign and easily recycled oxidants, solutions of H₂O₂ and Ce(SO₄)₂, the electrochemical performance of a natural graphite anode material can be markedly improved. Through thermogravimetric analysis, differential thermal analysis, X-ray photoelectron spectroscopy, high resolution electron microscopy and measurements of lithium capacity it was found that the surface structure of the natural graphite was modified with a dense layer of oxides, which could prevent the co-intercalation of solvent molecules. In addition, the stability of the graphite crystal was improved and the decomposition of electrolyte molecules was prohibited. Furthermore, a large number of nano-channels were introduced by oxidation, which favored lithium intercalation and de-intercalation. The reversible lithium capacity was enhanced from 251 to >330 mA h g⁻¹, and no capacity fading was observed in the first 10 cycles. This green method is also highly efficient and economical, the process can be performed below 60 °C.