Open AccessAnalysis of Intercalation/De-Intercalation of Li Ions Into/From Graphite at 0 °C via Operando Synchrotron X-ray Diffraction
Author(s) -
Hiroyuki Fujimoto,
Shinji Takagi,
Kei Shimoda,
Hisao Kiuchi,
Kenichi Okazaki,
Tetsuyuki Murata,
Zempachi Ogumi,
Takeshi Abe
Publication year - 2021
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ac2280
Subject(s) - intercalation (chemistry) , graphite , synchrotron , graphite intercalation compound , diffraction , ion , materials science , x ray crystallography , crystallography , chemistry , analytical chemistry (journal) , inorganic chemistry , optics , organic chemistry , physics
The charge/discharge reaction mechanisms of graphite negative electrodes in Li ion batteries were investigated via operando synchrotron X-ray diffraction at 0 °C and 25 °C. The intercalation of Li ions at 25 °C formed the stage 1 compound with an in-plane structure of LiC 6 ; while intercalation at 0 °C only formed stage 2, with in-plane structures of LiC 9 and LiC 6 . The degree of graphite expansion in the a, b -axes and c -axis directions by intercalation at 0 °C was less than that at 25 °C. Hence, it was difficult to form the stage 1 structure by further increases in the Li ion concentration, and the charging reaction at low temperature became difficult. De-intercalation at 0 °C did not follow the Daumas–Hérold model and proceeded discretely in the order: stage 1 → stage 2 → stage 4 → graphite, without going through stages 3, 5–8 and dilute stage 1.