Preparation method of bulky-grain spinel lithium manganate material

Abstract

The invention discloses a preparation method of a bulky-grain spinel lithium manganate material, which belongs to the field of electrochemical materials. The bulky-grain spinel lithium manganate material is prepared through carrying out high-temperature sintering on a raw material such as manganese dioxide or manganese carbonate as with a doped element M to be converted into uniformly-doped bulky-grain mangano-manganic oxide, using the bulky-grain mangano-manganic oxide as the raw material of a Mn source, mixing the bulky-grain mangano-manganic oxide with an original material of Li, and sintering the obtained mixture. The mangano-manganic oxide prepared by the invention has a good crystalline grain shape; the grain size is in normal distribution; after the bulky-grain mangano-manganic oxide is used as the raw material of the Mn source and mixed with the original material of the Li, a bulky-grain lithium manganate product with a low surface area can be obtained without the obtained miture at a temperature which exceeds 900 DEG C; and the problem that oxygen loss is caused when the bulky-grain lithium manganate is prepared by high sintering exceeding 900 DEG C is solved. The lithium manganate prepared by the method has uniform granularity; the average grain size of the lithium manganate can be controlled in a range of 5-15 mum through the process; the specific surface area is between 0.2 m<2> / g and 0.6 m<2> / g; crystalline grains are complete; and the high-low temperature cycle service is excellent. The method provided by the invention has a simple process and low cost, and is applicable to industrial production.

Description

technical field [0001] The invention relates to a preparation method of a large-grain spinel lithium manganese oxide material, which belongs to the technical fields of electrochemistry, powder metallurgy and electronic products. Background technique [0002] Cathode materials are an important part of secondary lithium-ion batteries, and their performance and cost play a key role in the development and application of lithium-ion batteries. In the cost of lithium battery preparation, the positive electrode material accounts for the largest proportion, more than 30%. The positive electrode materials that have been developed so far mainly include layered lithium cobaltate, lithium nickelate, multi-component positive electrode, lithium manganate with spinel structure and lithium iron phosphate with olivine structure. The positive electrode materials of the above systems have their own advantages and disadvantages, and different systems are suitable for different battery products...

AI Technical Summary

Problems solved by technology

[0007] Generally, increasing the sintering temperature and increasing the sintering time are the most effective methods to increase the particle size of the material and reduce the specific surface area, but for lithium manganate materials, it must be calcined at a high temperature above 900 ° C for more than 10 hours to effectively reduce its specific surface area, but high temperature The degree of oxygen deficiency in the calcination process is serious, and it cannot be fully compensated even by annealing. Partial oxygen deficiency is extremely harmful to high and low temperature cycle life. Inappropriate high temperature calcination process, even if large particles with low specific surface area are prepared, but due to The existence of the oxygen deficiency problem makes the cycle life not only not improved, but worse

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