The present application relates to the technical field of
lithium ion battery additives, and provides a
lithium supplement additive, which includes α-crystalline
lithium nitride and / or β-crystalline
lithium nitride. The lithium supplement additive provided by the present application has a high lithium
ion conductivity of pure α-crystalline
lithium nitride, which is conducive to the release of lithium ions, a high lithium
ion migration energy barrier of pure β-crystalline
lithium nitride, and a high
decomposition voltage, which makes the migration of lithium ions in the
battery system more stable, and the mixed crystalline lithium
nitride contained has reduced activity, which can avoid the reaction with widely used N-methylpyrrolidone (NMP) and
polyvinylidene fluoride (PVDF) in the homogenization process, and has good stability. Therefore, when the lithium
nitride provided by the present application is used as a lithium supplement additive, the lithium nitride can supplement the lithium ions consumed by the negative
electrode to form the SEI film during the first cycle of charging of the battery, so that the lithium ions in the
battery system remain abundant, improve the first charging efficiency and overall electrochemical performance of the battery, and the
voltage changes steadily during the charging process.