石墨Gibbs表面自由能对锂离子电池传统负极浆初始黏度和稳定性的影响

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

负极浆料的初始黏度和稳定性对锂离子电池的生产工艺和后期性能至关重要。但是关于石墨原料的理化性质对负极浆料初始黏度和稳定性的影响尚未从根本上阐明。通过对不同粒度和比表面积的商业化石墨进行初始黏度测试,发现负极浆料的初始黏度与石墨的非极性Gibbs表面自由能呈正相关。同时还发现,Gibbs表面自由能极性部分和非极性部分的相对大小对负极浆料的稳定性有影响。当Gibbs表面自由能极性部分接近非极性部分时,制备的浆料具有最佳的稳定性,且静置120 h以后克容量保持稳定。有趣的是,XRD和Raman光谱表征结果显示石墨粒子的Gibbs表面自由能与缺陷之间没有直接的线性关系。本研究可为锂离子电池工业生产中石墨原料的选择提供指导。

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.