Preparation method of lithium titanate composite negative electrode material

Abstract

The invention relates to a preparation method of a lithium titanate composite negative electrode material. The method comprises the steps of (1) weighing a lithium salt and titanium dioxide with a mole ratio of Li:Ti being (4.2-4.6):5 according to a matching ratio, placing the lithium salt and the titanium dioxide in a ball-milling tank, adding a dispersion agent and zirconium spheres, performing wet ball milling and uniform mixing, and drying the material after ball-milling; (2) placing a dried material in a CVD (Chemical Vapor Deposition) furnace, adding graphite and silicon oxide, and introducing an inert gas, wherein the weight matching ratio of the dried material, the graphite and the silicon oxide is as follows: 75-80 parts of dried material, 9-12 parts of graphite and 9-12 parts of silicon oxide; and (3) adjusting a parameter and a sintering condition of the introduced gas, and synthesizing the lithium titanate composite negative electrode material. The preparation method has the advantages of reasonable process, low cost, stable product performance and excellent electrochemical performance.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a preparation method of a lithium titanate composite negative electrode material. Background technique [0002] The rapid development of lithium-ion batteries depends on the development of new energy materials and the progress of comprehensive technologies. Among them, the exploration and research of new electrode materials, especially negative electrode materials, is particularly important. Since the emergence of commercial lithium-ion batteries, graphite negative electrodes have firmly occupied the With the dominance of lithium-ion battery anode materials, from artificial graphite, natural graphite, to mesophase graphite, the theoretical capacity of graphite materials is close to 372mAh / g, which seriously restricts the improvement of the energy density of lithium-ion batteries. Compared with graphite materials Lithium titanate has obvious advantages. L...

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Problems solved by technology

[0002] The rapid development of lithium-ion batteries depends on the development of new energy materials and the progress of comprehensive technologies. Among them, the exploration and research of new electrode materials, especially negative electrode materials, is particularly important. Since the emergence of commercial lithium-ion batteries, graphite negative electrodes have firmly occupied the With the dominance of lithium-ion battery anode materials, from artificial graphite, natural graphite, to mesophase graphite, the theoretical capacity of graphite materials is close to 372mAh / g, which seriously restricts the improvement of the energy density of lithium-ion batteries. Compared with graphite materials Lithium titanate has obvious advantages. Lithium titanate is a zero-strain material with good cycle performance, stable discharge voltage, and good safety performance; while silicon is used as a negative electrode material for lithium-ion batteries, each atom can combine up to 4.4 lithium atoms , in which silicon atoms form a Li22Si5 alloy, the theoretical specific capacity is as high as 4200mAh / g, and the lithium site is low, but this material also has a disadvantage. In the deintercalation cycle, the silicon lattice and microstructure change greatly. Severe volume expansion and shrinkage occur; therefore, it is necessary to provide a preparation method of lithium titanate composite negative electrode material with reasonable process, low cost, stable product performance and excellent electrochemical performance