Preparation method of single crystal large particles of ternary material

Abstract

The invention provides a preparation method of single crystal large particles of a ternary material, and belongs to the field of lithium ion batteries. The preparation method mainly comprises the following steps: (1) mixing the main element raw material of a ternary material, a uniform precipitant, a template agent and a fluxing agent in deionized water according to a certain stoichiometric ratioto obtain a mixed solution; (2) transferring the mixed solution into a reaction kettle, carrying out heat preservation for a period of time at a certain temperature, and carrying out a hydrothermal reaction to obtain a corresponding uniform ternary material precursor; and (3) adding a lithium source into the precursor, and carrying out high-temperature calcination to obtain single crystal particles. According to the invention, urea is used as a uniform precipitant so as to slowly and uniformly release CO3<2-> ions in the solution, so that the phenomenon of non-uniform local distribution causedby directly adding the precipitant from the outside can be overcome; and a template agent and a soluble fluxing agent are uniformly added into a precursor by adopting a hydrothermal method, so that agglomeration can be effectively prevented.

Description

technical field [0001] The invention belongs to the field of lithium ion battery materials, and in particular relates to a method for preparing large single crystal particles of ternary materials. Background technique [0002] With the innovation of new energy material research and development technology, lithium-ion batteries with advantages such as low-carbon environmental protection, high energy density, and wide operating temperature range have received widespread attention. At present, LiFeO with good safety is mostly used as the positive electrode material of lithium ion battery on the market. 4 , but LiFeO 4 Low capacity is not enough to meet the increasing demand for high energy density batteries, so ternary materials have become a research hotspot due to their high energy density. Ternary materials are mostly spherical, and the primary particle size is generally around several hundred nanometers. Side reactions between surface particles and electrolyte are prone t...

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Problems solved by technology

Patent application CN108232186A discloses that in the synthesis of single crystal particles, an expanded precursor is prepared by a polymer template, and then the powder with volume expansion after thermal polymerization is sintered to obtain the required single crystal positive electrode material, but this method is in the process of preparing The introduction of strong acids such as nitric acid and sulfuric acid in the process of precursors in order to improve solubility and achieve uniform mixing will pollute the environment

Patent application CN106159251A discloses the method of adding flux to reduce the melting point of the material, which reduces the number of sintering times and sintering time in the current single crystal material synthesis process, but the flux, precursor and lithium source are mixed by mechanical mixing. Uniformity of mixing and consistency of single crystal growth rate cannot be guaranteed

At the same time, the literature "Zhong Weipan et al." different precipitants have different effects on the prepared LiNi(0.8)Co(0.1)Mn(0.1)O 2 A study on the influence of positive electrode materials on the performance of "[J]. Functional Materials, 2012, 43(11): 1425-1430." Ionic compounds NaOH and NaOH were used in 2 CO 3 As a precipitating agent for the reaction, since the precipitating agent used is an ionic compound, the carbonate group is released quickly when it meets water, and the combination with the main metal element is not complete, so the amount of the auxiliary agent required is large, which is prone to pollution and waste.

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