A kind of preparation method of lithium manganese phosphate lithium battery cathode material

Abstract

The invention discloses a preparation method for a lithium battery positive material LiMnPO4. The preparation method comprises the following steps of: dissolving and mixing a water-soluble manganese source compound, a phosphate source compound, a lithium source compound and a chelating agent citric acid according to a sequence; adding a high-boiling point compound dimethylsulfoxide (DMSO); heating the mixture to obtain a product LiMnPO4; mixing the product with an appropriate amount of carbon source; and sequentially grinding, heating and calcining to obtain a LiMnPO4 / C material. According to the preparation method, the product LiMnPO4 can be prepared at a low temperature and a normal pressure, a certain amount of the high-boiling point compound is added and mixed with water to serve as a reaction solvent, thus, the boiling point of the whole reaction system is increased, the reaction energy barrier is reduced, the dynamic behavior of liquid-phase reaction is improved, and the reaction can be carried out at the low temperature less than 150 DEG C and the normal pressure of 1 mm.Hg.

Description

technical field [0001] The invention relates to a preparation method for preparing lithium battery cathode materials, in particular to a preparation method for cathode material lithium manganese phosphate under low temperature and normal pressure, and belongs to the technical field of preparation of new energy materials. Background technique [0002] With the large-scale use of electrical energy storage devices, electric vehicles and power tools, researchers have focused a lot of attention on the cycle life, safety and high energy density of lithium-ion batteries. At present, in lithium battery cathode materials, polyanion cathode materials are widely researched and applied as lithium ion cathode materials. Especially LiFePO 4 Compared with traditional cathode materials, cathode materials are widely used because of their higher chemical stability, better safety performance, and higher cycle life. [0003] But LiFePO 4 The material also has its own inherent shortcomings. O...

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Problems solved by technology

[0013] Among the commonly used preparation methods, the high-temperature solid-state reaction method is the most commonly used method. However, this synthesis method has a long reaction time, cumbersome operation, low efficiency, and large energy consumption. The particle size distribution of the final product obtained is Inhomogeneous, prone to agglomeration and other phenomena, and the specific capacity of the obtained product is often not high;

[0014] Although the preparation process of the hydrothermal method is relatively simple, the obtained phase is uniform and the particle size is small, but it is limited to the preparation of small particles, and in the hydrothermal process, the ions are prone to mixing. If it is to reach the mass production level , will be subject to many restrictions, especially the high temperature and high pressure environment it needs, which is difficult to realize. In addition, the design and manufacture of high temperature and high pressure reaction vessels are also difficult and expensive

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