Nano lithium titanate material with high-density structure and preparation method of nano lithium titanate material

Abstract

The invention relates to a nano lithium titanate material with a high-density structure and a preparation method thereof, and belongs to the technical field of lithium ion batteries. The invention discloses a nano lithium titanate material with a high-density structure. The nano lithium titanate material is prepared from the following raw materials: a titanium source, a lithium source, a surface and bulk phase modifier and a macromolecular modifier, wherein the addition amount of the surface and bulk phase modifier accounts for 0.05%-0.5% of the total weight of the titanium source and the lithium source, and the addition amount of the polymer modifier accounts for 1%-5% of the total weight of the titanium source and the lithium source. The invention also discloses a preparation method of the nano lithium titanate material with the high-density structure, and the preparation method comprises the following steps: sequentially dispersing a titanium source and a lithium source in a mixed solution containing the surface and bulk phase modifier and the high-molecular modifier, and then carrying out grinding and ultrasonic dispersion treatment to obtain the nano lithium titanate material with the high-density structure. Then carrying out spray drying granulation on the nano precursor slurry to obtain nano lithium titanate precursor powder; and calcining to obtain the nano lithium titanate material.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and relates to a high-density structure nano-lithium titanate material and a preparation method thereof. Background technique [0002] As a new type of negative electrode material for lithium-ion power and energy storage lithium-ion batteries—lithium titanate (Li 4 Ti 5 o 12 ) has distinct performance advantages. First of all, as a "zero strain material", lithium titanate has a volume strain of less than 1% during charge and discharge, so it has very good cycle performance. Secondly, its discharge voltage is relatively stable and will not decompose the electrolyte, which improves the overall safety performance of lithium batteries. Then, the lithium titanate material has a higher lithium ion diffusion coefficient than the carbon material, and can be charged in a few minutes. It is difficult to precipitate lithium dendrites even in a low-temperature environment, so high-rate char...

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Problems solved by technology

[0003] However, lithium titanate is used as the negative electrode of lithium-ion batteries, and its commercialization progress is affected by its own disadvantages

First of all, due to the bandgap energy of its Ti3d orbital ~ 2.0eV, it approximates the conductivity of an insulator, which makes it not perform well in high-rate applications; and lithium titanate cannot be formed like a carbon negative electrode in the actual use voltage range. Stable SEI film to inhibit the occurrence of gas production reaction, so the electrolyte is always in direct contact with the surface of lithium titanate during charging and discharging, so that the electrolyte continues to reduce and decompose on the surface of lithium titanate, which is the root cause of battery flatulence; In addition, the low theoretical capacity (175mAh / g) of lithium titanate material limits its practical application.

In fact, the current lithium titanate materials have shortcomings such as poor high-rate performance and low capacity, and batteries assembled from lithium titanate materials have safety factors such as flatulence, which hinders the commercialization of lithium-ion batteries with lithium titanate as the negative electrode. application

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