LITHIUM SUPPLEMENT ADDITIVE, PREPARATION METHOD THEREFOR, AND APPLICATION THEREOF

The present application relates to the technical field of lithium-ion battery additives, and provides a lithium supplement additive comprising α-phase lithium nitride and/or β-phase lithium nitride. According to the lithium supplement additive provided by the present application, the comprised pure α-phase lithium nitride has high lithium ion conductivity, thereby facilitating the de-intercalation of lithium ions; the comprised pure β-phase lithium nitride has a high energy barrier for lithium-ion mobility and a high decomposition voltage, so that the mobility of lithium ions in a battery system is more stable; and the comprised mixed-phase lithium nitride has reduced activity and can be prevented from reacting with widely used N-methylpyrrolidone (NMP) and polyvinylidene fluoride (PVDF) during a homogenizing process, and thus has good stability. Therefore, if the lithium nitride provided by the present application is used as a lithium supplement additive, during a first charging process of a battery, the lithium nitride can supplement lithium ions consumed for forming an SEI film on a negative electrode, thereby keeping lithium ions in a battery system sufficient, improving the efficiency of the first charging and the overall electrochemical performance of a battery, and achieving a stable voltage change during a charging process.