Correlation between the physical parameters and the electrochemical performance of a silicon anode in lithium-ion batteries

Abstract

Lithium-ion battery anode used as silicon particles were obtained from different major suppliers, and they were characterized by different spectroscopic techniques and evaluated by electrochemical experiments. Correlations between the key physical parameters and electrochemical properties of the silicon particles were investigated. Silicon particle size, surface oxygen content, -OH content and physical appearance are found to strongly influence the electrochemical properties of the Si anode. The particle size of 100 nm has great promise for the practical application of Si nanoparticles in the lithium-ion battery industry. An inverse correlation between the oxygen content and the reversible capacity or first coulombic efficiency was obtained. The -OH content by surface treatment contributes to enhanced cycling stability by the improved affinity between the Si particle and the water-soluble binder. Spherical Si particles perform better compared to irregular particles, and agglomeration dramatically decreases the cycling stability of the Si anode. Among the investigated Si particles, the sample that exhibited a reversible capacity of more than 2500 mAh g−1, a first coulombic efficiency of 89.26% and an excellent cycling stability, has great potential for use in the battery industry. Keywords: Lithium ion batteries, Silicon anode, Physical parameters, Particle size, Surface condition