Investigations on the modified natural graphite as anode materials in lithium ion battery

Two kinds of natural graphite samples, flake graphite (FG) and microcrystalline graphite (MG) have been used as anode materials in lithium ion battery after various modifications based on the structural difference between FG and MG. FG should be focused on improving the cycle stability while MG on the initial cycle efficiency. Spherical treatment, particle grading and surface coating are effective to improve their electrochemical performance. Especially, mild-expansion modification was used to introduce defects into FG's structure, which greatly improved its cycle stability and capacity. Both FG and MG are promising commercial anode materials after a series of modifications. (C) 2007 Elsevier Ltd. All rights reserved.