Understanding the crack formation of graphite particles in cycled commercial lithium-ion batteries by focused ion beam - scanning electron microscopy

Journal Article · 30 September 2017 · Journal of Power Sources

DOI: https://doi.org/10.1016/j.jpowsour.2017.08.045 · OSTI ID:1426725

Lin, Na ^[1]; Jia, Zhe ^[2]; Wang, Zhihui ^[2]; Zhao, Hui ^[2]; Ai, Guo ^[3]; Song, Xiangyun ^[2]; Bai, Ying ^[4]; Battaglia, Vincent ^[2]; Sun, Chengdong ^[5]; Qiao, Juan ^[6]; Wu, Kai ^[5]; Liu, Gao  ^[2]

---

1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Storage and Distributed Resources Division, Energy Technologies Area; Tsinghua Univ., Beijing (China). Dept. of Chemistry
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Storage and Distributed Resources Division, Energy Technologies Area
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Storage and Distributed Resources Division, Energy Technologies Area; Science and Technology on Reliability Physics and Application of Electronic Component Lab., Guangzhou (China). No.5 Electronic Research Inst. of the Ministry of Industry and Information Technology
4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Storage and Distributed Resources Division, Energy Technologies Area; Beijing Inst. of Technology, Beijing (China). School of Chemical Engineering & Environment
5. Ningde Amperex Technology Co. Ltd, Ningde, Fujian (China). Research Inst.
6. Tsinghua Univ., Beijing (China). Dept. of Chemistry

Here in this paper, the structure degradation of commercial Lithium-ion battery (LIB) graphite anodes with different cycling numbers and charge rates was investigated by focused ion beam (FIB) and scanning electron microscopy (SEM). The cross-section image of graphite anode by FIB milling shows that cracks, resulted in the volume expansion of graphite electrode during long-term cycling, were formed in parallel with the current collector. The crack occurs in the bulk of graphite particles near the lithium insertion surface, which might derive from the stress induced during lithiation and de-lithiation cycles. Subsequently, crack takes place along grain boundaries of the polycrystalline graphite, but only in the direction parallel with the current collector. Furthermore, fast charge graphite electrodes are more prone to form cracks since the tensile strength of graphite is more likely to be surpassed at higher charge rates. Therefore, for LIBs long-term or high charge rate applications, the tensile strength of graphite anode should be taken into account.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Natural Science Foundation of China (NNSFC)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1426725
• Alternate ID(s): OSTI ID: 1495798
• Journal Information: Journal of Power Sources, Journal Name: Journal of Power Sources Journal Issue: C Vol. 365; ISSN 0378-7753
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English