Structural relaxation behavior of nano silicon-graphite composite anode after lithium-ion insertion

The relaxation behavior of nano silicon-graphite composite anode in lithium-ion half-cell just after the termination of lithiation has been investigated by the X-ray diffraction (XRD) method under argon atmosphere. The diffraction peaks of stage I of lithium graphite intercalation compound (Li-GIC) turned into those of stage II during the relaxation process, indicating that lithium-ions migrated from Li-GIC into Si toward the equilibrium lithium distribution between Li-GIC and Si side. While the amounts of lithium-ion migration were related to the amount of Si content in the anode, the rate constant depends on the charging current density.