Relaxation Analysis of Silicon Monoxide-Graphite Composite Anode

Abstract

Relaxation analysis based on X-ray diffraction has been carried out on SiO-graphite composite anode of the lithium-ion battery, focusing on the lithium migration during the relaxation accompanied by the stage change of lithium graphite intercalation compound (Li-GIC). After the termination of electrochemical lithium insertion, XRD peaks of Li-GIC change from stage I into stage II during the relaxation. Due to the slower reaction for lithiation of SiO in comparison with the intercalation of Li-GIC, lithium migration from Li-GIC toward SiO to change the Li-GIC from stages I into II toward the equilibrium lithium distribution. The stage change is more apparent for higher current density at the charging, presumably due to the core–shell model of lithium concentration of SiO after charging.