Positive electrode lithium supplement additive and preparation method and application thereof

The invention discloses a positive electrode lithium supplement additive and a preparation method and application thereof. The positive electrode lithium supplement additive comprises a lithium supplement material, the lithium supplement material further contains fluorine atoms, and the fluorine atoms replace oxygen atoms in the lithium supplement material and are located in oxygen vacancies. Compared with the prior art, the positive electrode lithium supplement additive adopts fluorine doping, has relatively good high-voltage and thermal stability performance and relatively high rate performance, reduces the content of residual alkali, has high storage stability and good processing performance, and also can reduce the gas production rate, so that the cycle and electrochemical performance and the safety performance of a corresponding battery are improved. In addition, the preparation method of the positive electrode lithium supplement additive can ensure that the prepared positive electrode lithium supplement