Lithium ferromanganese phosphate and preparation method thereof

Abstract

The invention relates to a preparation method of lithium ferromanganese phosphate. The method comprises the steps of: (1) mixing elemental iron, manganese dioxide and a phosphoric acid aqueous solution to obtain a mixture A, and subjecting the mixture A to ball milling to obtain ferromanganese hydrogen phosphate; and (2) mixing the ferromanganese hydrogen phosphate, lithium carbonate and glucose,and performing sand milling to a product particle size D50 of 0.2microm-1microm, and conducting drying and calcination to obtain lithium ferromanganese phosphate. The method has the characteristics ofsimple equipment and process, good atomic economy, small environmental pressure and low manufacturing cost, is easy for industrial production, and by controlling the particle size of the final product, the specific discharge capacity of lithium ferromanganese phosphate serving as a battery cathode material is increased.

Description

technical field [0001] The invention relates to the field of preparation of positive electrode materials for lithium ion batteries, in particular to lithium manganese iron phosphate and a preparation method thereof. Background technique [0002] With the continuous development of electronic equipment such as spacecraft, electric vehicles, medical equipment, and communication equipment, relatively mature binary lithium batteries, such as lithium iron phosphate and lithium manganese phosphate batteries, have gradually improved in terms of charge and discharge voltage, conductivity and service life. Show limitations. Nowadays, the use of a new generation of ternary material lithium manganese iron phosphate as the positive electrode of the battery has the advantage of higher rate performance and cycle performance. Therefore, lithium manganese iron phosphate material is more and more valued by various battery manufacturers. [0003] According to reports, some researchers used so...

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Problems solved by technology

However, this method will use an organic solvent on the one hand, and an autoclave on the other hand. Again, the amount of lithium used in solvent hydrothermal synthesis is three times the theoretical amount, and the excess lithium requires a complicated recovery process.

This method has high requirements on equipment, complicated process, and difficulty in material recovery, resulting in high production costs, which is not conducive to the large-scale production of lithium iron phosphate

[0004] According to reports, there are also researchers who use ion iron source and ion manganese source to prepare lithium manganese iron phosphate, for example, use ferrous sulfate, ferrous nitrate or ferrous acetate as iron source and use manganese nitrate or manganese oxalate as manganese source as a reaction Raw material, then add lithium source and carbon source to synthesize manganese iron phosphate lithium, this method needs to adjust pH value in reaction process, so reaction intermediate product must wash (for example, every ton of ferric phosphate needs to be washed with ferrous sulfate about 100 tons), phosphorus-containing and sulfate-containing washing water treatment will bring higher costs to production, greatly increase production costs, and poor atom economy

[0005] In addition, it is also reported that ammonium ferric manganese phosphate is first synthesized in aqueous solution, and then lithium manganese ferric phosphate is synthesized, but the ammonia volatilization in this method causes great pollution to the production environment

[0006] In summary, the current preparation methods of lithium manganese iron phosphate have problems such as complex process, high cost, high sewage pressure and poor atom economy.

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