Synthesis method for structurally stable spinel lithium-manganese oxide for lithiumion cell

Abstract

The present invention relates to the preparation of cell material and features that the spinel lithium-manganese oxide is preapred through the material processing of mixing bismuth trioxide, lithium carbonate, electrolytic manganese dioxide; the reaction process of adding ethanol to the mixture, ball milling, natural cooling, eliminating ethanol, four times of constant temperature heating and eliminating water to promote the conversion of MnO2 to Mn2O3, eliminate CO2 and form spinel lithium-manganese oxide; and the natural cooling, grinding and sieving after reaction. The method of the present invention is simple and can ensure that the synthetic lithium-manganese oxide maintains stable spinel structure during charge and discharge and has high capacity.

Description

(1) Technical field: [0001] The invention relates to a method for synthesizing spinel lithium manganese oxide with stable structure for lithium ion batteries, which belongs to the battery industry material preparation technology. (two) background technology: [0002] The rapid development of the electronics industry requires a power supply with high power and high energy density. The emergence of rechargeable lithium-ion batteries largely meets this requirement. The positive active material is one of the important factors that determine the performance of lithium-ion batteries. Lithium cobalt oxide LiCoO with layered structure can be used as the positive electrode active material of lithium ion battery 2 and lithium nickel oxide LiNiO 2 , and the spinel-structured lithium manganese oxide LiMn 2 o 4 ; Theoretically, the three oxides can be charged and discharged according to the following reactions in the lithium-ion battery and can obtain the corresponding theoretical c...

AI Technical Summary

Problems solved by technology

But in fact, the spinel structure of lithium manganese oxide is not stable enough. Even if the discharge is above 3V, under dynamic non-equilibrium conditions, some crystals may intercalate more lithium than others, making the electrode surface component become trivalent manganese. Enriched Li 1+x mn 2 o 4 , resulting in a tetragonal crystal system

The enrichment of trivalent manganese will accelerate the dissolution of spinel, and at the same time, poor contact between tetragonal crystals and tetragonal crystals may also occur

[0008] The purpose of the present invention is to overcome and solve the shortcomings and problems of unstable structure of pure lithium manganese oxide, serious loss of capacity of doped lithium manganese oxide, and impracticality, and to research and invent a lithium manganese oxide with stable structure for lithium ion batteries. The synthesis method of the compound, the method can make the lithium manganese oxide not only maintain the stable spinel structure in the process of charge and discharge, but also have a higher capacity by adding a small amount of bismuth to modify the spinel.

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