Analysis of Intercalation/De-Intercalation of Li Ions Into/From Graphite at 0 °C via Operando Synchrotron X-ray Diffraction. Issue 9 (8th September 2021)

• Record Type: Journal Article
• Authors: Fujimoto, Hiroyuki; Takagi, Shigeharu; Shimoda, Keiji; Kiuchi, Hisao; Okazaki, Ken-ichi; Murata, Tetsuyuki; Ogumi, Zempachi; Abe, Takeshi
• Is Part Of: Journal of the Electrochemical Society. Volume 168:Issue 9(2021)
• Publication Date: 2021-09-08
• Subjects: Batteries—Li-ion -- X-ray diffraction -- Energy Storage; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/1945-7111/ac2280
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : 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 LiC6 ; while intercalation at 0 °C only formed stage 2, with in-plane structures of LiC9 and LiC6 . 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.