A kind of lithium manganate battery material and preparation method thereof

Abstract

The invention provides a lithium manganate battery material and a preparation method thereof, the method comprising the following steps: (1) performing the first sintering after mixing manganese source compound, lithium source compound, M source compound and L source compound, get Li x mn 2‑a‑b m a L b o 4 Material; (2) step (1) is obtained Li x mn 2‑a‑b m a L b o 4 After the material is pulverized, it is mixed with the L source compound and the A source compound for the second sintering to obtain the surface layer doped with L c A d Li x mn 2‑a‑b m a L b o 4 The single crystal particle; (3) the surface layer that step (2) obtains is doped with L c A d Li x mn 2‑a‑ b m a L b o 4 After the single crystal particles are pulverized, the third sintering is carried out in an oxygen atmosphere to obtain the lithium manganate battery material. The lithium manganate battery material of the invention has a small specific surface area, less contact between sites with high surface activity and electrolyte, and less side reactions; the lithium manganate battery material has a stable surface layer and internal structure, and has excellent high-temperature cycle performance.

Description

technical field [0001] The invention relates to the field of lithium ion battery materials, in particular to a lithium manganate battery material and a preparation method thereof. Background technique [0002] With the continuous development of lithium-ion battery technology, ternary cathode materials such as lithium cobalt oxide and lithium manganese oxide have experienced a stage from birth to development, and gradually tended to perfection. Although the current commercial lithium-ion batteries can cope with most of the market However, some high-end market products still put forward higher commercial requirements for cathode materials, such as the application of lithium cobalt oxide at higher voltage and high rate, the demand for higher compaction and higher capacity of ternary materials and manganese acid Lithium is required for higher temperature resistance and long cycle. [0003] Compared with lithium cobalt oxide and ternary materials, the cycle performance of lithiu...

AI Technical Summary

Problems solved by technology

During the charging and discharging process of the battery, the manganese on the surface of the lithium manganate particles is more likely to undergo a disproportionation reaction in contact with the electrolyte, resulting in the destruction of the surface structure. At the same time, the divalent manganese ions obtained by the reaction can be dissolved in the electrolyte. Negative electrode deposition affects the stability of the SEI film on the surface of the negative electrode and the transport of lithium ions

In addition, under high temperature conditions, this phenomenon will be more obvious, which will aggravate the Jahn-Teller effect of the structure, resulting in the distortion and destruction of the spinel structure of the particles.

[0004] There are many existing reports on the performance optimization of lithium manganate cathode materials. The Chinese patent application number 201110355755.X prepares single crystal lithium manganate by using manganese source compound, M source compound and lithium source compound as raw materials. The surface coating modification of this type of single crystal particles is carried out by source compound A and melting agent, which not only improves the processability of lithium manganate single crystal particles, but also further optimizes the high temperature cycle performance of lithium manganate particles, but Due to the large specific surface area of ​​the prepared lithium manganate, the content of the required coating is high, and the coating with a low melting point needs to be spread evenly to protect the surface layer, resulting in poor high temperature cycle performance of the material.

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