LITHIUM-ION BATTERY POSITIVE ELECTRODE LITHIUM SUPPLEMENT ADDITIVE, PREPARATION METHOD THEREFOR, AND LITHIUM-ION BATTERY

A lithium-ion battery positive electrode lithium supplement additive, a preparation method, and a lithium-ion battery are provided. The additive has an LiNiO purity that is greater than 95%, a total residual alkali less than 3%, an initial charge gram capacity of 420-465 mAh/g, and an irreversible capacity of 260-340 mAh/g. The method includes: preparing a composite lithium salt, mixing the composite lithium salt with a nickel source, sintering and crushing same, and obtaining the lithium-ion battery positive electrode lithium supplement additive. The additive is added to a positive electrode active material of the positive electrode of the lithium-ion battery. The LiNiO obtained has a purity of greater than 95%, the total residual alkali is less than 3%, the initial charge gram capacity is 420-465 mAh/g, and the irreversible capacity is 260-340 mAh/g.