Influence of edge and basal plane sites on the electrochemical behavior of flake-like natural graphite for Li-ion batteries

The irreversible capacity loss (ICL) that is observed with carbons in Li-ion batteries is associated with electrolyte decomposition. In this paper, we present the results of an analysis to illustrate the role that the edge and basal plane sites play on the ICL and first-cycle coulomb efficiency of flake-like natural graphite. A model of an ideal graphite particle, which is depicted as an ideal prismatic structure, is used to develop an understanding of the correlation of the fraction of edge sites and particle size for flake-like and cube structures. In the case of flake-like graphite, thin flakes have higher surface area and higher ICL than thicker flakes, even though the fraction of edge sites is lower. On the other hand, the cube structure has a high fraction of edge sites but a low ICL and low surface area. The analysis presented here suggests that the particle morphology and the surface area associated with the edge and basal plane sites play a significant role in the electrochemical performance of graphite in Li-ion batteries. (C) 2001 Elsevier Science B.V. All rights reserved.