Influence of graphite Gibbs surface free energy on the initial viscosity and stability of traditional anode slurry in lithium-ion batteries

• Published in: Journal of Central South University 2023-03, Vol.30 (3), p.665-676
• Main Authors: Zhou, Qi, Wen, Bo, Zhang, Jia-li, Liu, Feng, Ouyang, Xiao-ping, Liang, Yi-li, Wu, Ze-yi, Xie, Zhi-yong
• Format: Article
• Language: English
• Subjects: Engineering; Free energy; Graphite; Lithium; Lithium-ion batteries; Metallic Materials; Physical properties; Raman spectra; Raw materials; Rechargeable batteries; Slurries; Viscosity
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-023-5250-7

The initial viscosity and stability of anode slurry are important for the manufacturing process and later the lithium-ion battery’s performance. The impact of the physical properties of graphite feed material on the anode slurry’s initial viscosity and stability is fundamentally unclarified. In this study, it is discovered that the initial viscosity of an anode slurry is positively associated with non-polar part of its Gibbs surface free energy and linear independence between them is established after slurry’s viscosity test of commercial graphite with different particle size and specific surface area. It is also discovered that the anode slurry’s stability is affected by the relative size of a polar and non-polar part of Gibbs surface free energy. The slurry reveals the best stability and good specific capacity retention after >120 h rest time when polar Gibbs surface free energy is close to the non-polar part. Interestingly, there is no direct linear relationship between Gibbs surface free energy and defect of graphite particles characterized using XRD and Raman spectra. This study guides how to select graphite raw materials in the industrial production of lithium-ion batteries.