LiMnPO4 hollow microsphere with controllable structure and preparation method and application thereof

Abstract

The invention discloses a LiMnPO4 hollow microsphere with a controllable structure and a preparation method and application thereof, and belongs to the technical field of positive electrode materialsfor lithium ion batteries. The method comprises the steps: S1, sodium hydroxide, lithium salt and phosphate are added into the mixed solvent of diethylene glycol and deionized water to fully react, and the reaction product is sequentially subjected to solid-liquid separation, washing and drying so as to obtain Li3PO4 hollow microspheres; and S2, the obtained Li3PO4 hollow microspheres, manganese salt and ammonium salt are added into a mixed solvent of ethylene glycol and deionized water and fully stirred, the stirred suspension is sealed in a reaction kettle, kept warm for a certain period oftime and then cooled to room temperature and the target product LiMnPO4 hollow microspheres are obtained after solid-liquid separation, washing and drying. The invention also discloses the applicationof the hollow microspheres in high-performance lithium ion battery positive electrode materials. The auxiliary additive ammonium salt can adjust the growth orientation of the assemble crystal grainsand adjust the assemble structure of the microspheres, and the obtained hollow microspheres have good crystallinity, accurate structure adjustment and control and excellent magnification performance.

Description

technical field [0001] The invention relates to the technical field of cathode materials for lithium-ion batteries, in particular to a structure-controllable LiMnPO 4 Hollow microsphere and its preparation method and application. Background technique [0002] Lithium-ion batteries have outstanding advantages such as high discharge voltage, high energy density, long cycle life, and environmental protection. They have been used in mobile phones, notebook computers, power tools, electric vehicles, smart grids, distributed energy systems, aerospace and national defense, etc. field. In lithium-ion batteries, the cathode material is an important part of the battery and the key to improving battery performance. As a cathode material for lithium-ion batteries, LiMnPO with orthorhombic forsterite structure 4 Compared with common commercial cathode materials, it has the advantages of strong safety, stable structure, environmental friendliness, and low price. It is one of the hotspo...

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Problems solved by technology

[0004] However, the use of these measures will bring new problems or shortcomings: the nano-grain will reduce the tap density of the material, resulting in a decrease in the volumetric energy density of the battery, which means that the improvement of the battery rate performance is at the expense of the volumetric energy density. At the expense of; in the preparation of the pole piece, it is difficult to disperse between the nanocrystalline grains, and it is prone to bridging, uneven dispersion, irregular agglomeration, etc., which makes it difficult to infiltrate the electrolyte and partially hinders the LiMnPO 4 The improvement of battery performance means that the processing performance of nano-grains needs to be improved; expanding the exposed area of ​​orthorhombic grains (010) crystal planes is easy to produce flaky grains, but flaky grains are easy to The phenomenon of mutual overlap makes it difficult for the electrolyte to enter the overlapping part, which partially restricts the LiMnPO 4 The further enhancement of battery performance means that the order of grain distribution needs to be improved while improving the orientation of grain growth

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