Method for coating lithium nickel manganese oxide with composite

Abstract

The invention discloses a method for coating lithium nickel manganese oxide with a composite, and belongs to the technical field of battery material modification and preparation. The method includes the steps that a lithium nickel manganese oxide precursor is prepared through a coprecipitation method and prepared into suspension, bismuth oxide and yttrium oxide in a certain proportion are added into the suspension, ball milling dispersion and drying are carried out, the dried material is subjected to roasting and annealing treatment in an air atmosphere, and the lithium nickel manganese oxide positive electrode material coated with the (Bi2O3)0.75(Y2O3)0.25 composite is obtained. The material prepared with the method is pure in phase and good in crystallinity, and industrial production of the material is easy; the surface of the lithium nickel manganese oxide material can be effectively coated with the (Bi2O3)0.75(Y2O3)0.25 composite to improve the cycle performance and rate capability of lithium-ion batteries; meanwhile, the coating layer can inhibit dissolution of manganese, reduce side reactions of the positive electrode material under high voltage and protect the structure and heat stability of the electrode material.

Description

technical field [0001] The invention relates to a lithium ion battery modification method, in particular to a method for coating lithium nickel manganese oxide with a composite material, and belongs to the technical field of battery material modification preparation. Background technique [0002] Energy is an important material basis for the development of human society and is related to the peace and stability of human beings and the world. In the 21st century, the energy crisis and environmental degradation have become two major problems to be solved in the world today, and due to the rapid development of space technology, mobile communications, missiles, aerospace, electric vehicles and other fields, there is a sharp demand for high-performance non-polluting chemical power supplies increase. Lithium-ion batteries belong to the field of clean energy and have the advantages of good safety, good cycle performance, long life, non-toxic and pollution-free, making them the fir...

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Problems solved by technology

The co-precipitation method is also a relatively common method. The main advantages of this method are that the synthesis temperature is low, the particle size of the product is small, and the composition is uniform. However, there are disadvantages such as different precipitation rates of different elements, and it is difficult to accurately control the composition and reaction rate of the product; Dongqian Liu et al. used co-precipitation method to synthesize lithium nickel manganese oxide material. Under the conditions of 0.2C rate and 3.5-4.9V, the material's first discharge specific capacity is 138mAh / g, and the capacity of 50 cycles has almost no decay (Liu Dong-qiang et al . Structure, morphology, and cathode performance of Li 1-x [Ni 0.5 mn 1.5 ]O 4 prepared by coprecipitation with oxalic acid [J]. Journal of Power Sources, 2010, 195:2918-2923)

The sol-gel method has good chemical uniformity of the precursor solution, low gel heat treatment temperature, small powder particle size and narrow distribution, good powder sintering performance, and easy control of the reaction process, but the drying shrinkage is large, industrialization is difficult, and the production cycle is long. B.J.Hwang et al. used sol-gel to synthesize lithium nickel manganese oxide material. The first discharge specific capacity at 0.1C rate was 132.6mAh / g, and the capacity retention rate after 25 cycles was 97.2% (Hwang B J et al. Influence of synthesis conditions on electrochemical properties of high voltageLi 1.02 Ni 0.5 mn 1.5 o 4 spinel cathode material[J]. Journal of Power Sources, 2009,193:828-833)

[0004] Spinel-type lithium nickel manganese oxide cathode materials have problems such as Jahn-Teller effect, disproportionation reaction and dissolution of manganese ions in the electrolyte, which lead to poor electrochemical cycle performance of the material

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