Abstract: Scrap artificial graphite used as negative material of lithium ion batteries was firstly oxidized with 30% H₂O₂ at room temperature, and then modified by two methods: LiOH impregnation and molten Li₂CO₃ coating technique with N₂ protection. X-ray diffraction and X-ray photoelectron spectroscopy analysis show that these two modification methods can form Li2CO3 film as similar SEI film on the graphite surface, and increase oxygen content and oxygenic functional groups on the graphite surface. Compared with that of untreated artificial graphite, the charge capacities of treated samples with oxidation and similar SEI formation increase from 255.5mAh/g to 323mAh/g upward, and the reversible capacity decreases a little in the first fifty cycles, keeping 317mAh/g. It proves that surface oxidation and similar SEI formation treatment can reduce lithium ion consumption, restrain decomposition of solvent and electrolyte, and improve coulombic efficiency.

Key words: lithium ion battery, scrap artificial graphite, oxidation and film formation, negative material