Lithium-supplementing composite positive electrode material, preparation method thereof, and lithium-supplementing method

Abstract

The present invention provides a lithium-supplementing composite positive electrode material, a preparation method thereof, and a lithium-supplementing method, which comprises, by mass percentage: 0.5% to 99% of doped lithium manganese oxide, 0.5% to 99% of a lithium ion positive electrode main material, and 0.5% to 10% of a conductive aid. The first effect of the lithium ion positive electrode main material is greater than the first effect of the doped lithium manganese oxide, and the doped lithium manganese oxide is a single-phase doped layered lithium manganese oxide having a C2 / m structure or a multi-phase doped lithium manganese oxide having both a C2 / m layered structure and a Fd‑3m spinel structure. The present invention composites the doped lithium manganese oxide having a low first effect characteristic with a high first effect main positive electrode material, and utilizes the irreversible release of Li from the low first effect component during the first cycle to offset the active Li consumed by the negative electrode to form an SEI film, thereby improving the initial capacity and cycle performance of the battery. Moreover, the material does not produce gaseous by-products when used, and the delithiation product still has good electrochemical properties, so it is highly safe.

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