Open AccessXRD studies on the electrode materials in the charge-discharge process of a graphite/Li（Ni1/3Co1/3Mn1/3）O2 battery
Author(s) -
L. S. Jia,
Yang Chuan-zheng,
Xigui Zhang,
Jian Zhang,
Xia Bao-Jia
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.6573
Subject(s) - intercalation (chemistry) , graphite , materials science , crystal structure , stacking , crystallography , ion , atom (system on chip) , crystal (programming language) , diffraction , lattice (music) , lattice constant , inorganic chemistry , chemistry , metallurgy , physics , organic chemistry , optics , computer science , acoustics , embedded system , programming language
Structure transformation and microstructure of the electrode active materials in a graphite / Li Ni1/3Co1/3Mn1/3O2 lithium ion battery during charge-discharge process have been studied by XRD. It is found that the lattice parameter of Li Ni1/3Co1/3Mn1/3O2, a and c, decrease and increase respectively. Its micro-strain ε and diffraction intensity ratio, I104/I101 and I012/I101, increases and decrease respectively, because Li atoms de-intercalate out of the crystal lattice of LiMO2. Meanwhile, the lattice parameter, a and c, micro-strain ε and stacking disorder P of 2H-graphite all increase, becausing Li atoms to intercalate into 2H-graphite.During charge process, Li atoms occupying 000 sites may preferentially de-intercalate from LiMO2 crystal lattice, and subsequently the Li atoms occupying 2/3 1/3 1/3and1/3 2/3 2/3sites de-intercalate from LiMO2. When intercalating into 2H-graphite, Li atoms preferentially occupy interstitial sites between C atom hexagonal net planes. When the stacking disorder degree reaches a given value, 3R-graphite phase may separate out gradually. When the battery has been fully charged or over charged, LiC12 and LiC6 phases can be formed. During discharge process, intercalation and de-intercalation behaviors of Li atoms are reversed. Li atoms may de-intercalate preferentially from interstitial sites of 2H-graphite and intercalate preferentially into 000 sites of LiMO2 crystal lattice. But these processes are not fully reversible.