Preparation method of carbon-coated lithium titanate

Abstract

The invention discloses a preparation method of carbon-coated lithium titanate, comprising the following steps of: 1) weighing and dispersing lithium source and titanium source in distilled water or deionized water; 2) adding long-chain aliphatic carboxylic acid to the water, heating the water to 30 to 100 DEG C, followed by uniform stirring and dispersion in order to obtain suspension; 3) transferring the suspension into a closed reaction container for being heated so that the suspension is subjected to reaction at constant temperature; 4) cooling reaction products to room temperature upon the end of the reaction, repeatedly washing with mixed liquid of alcohol and water, centrifuging and drying the reaction products, and collecting precursor; and (5) putting the collected precursor in an atmosphere furnace filled with non-oxidative gas to be roasted, and then cooling the roasted precursor to result in the carbon-coated lithium titanate. Compared with the prior art, the preparation method according to the invention achieves the formation of uniform carbon-coated layers under the protection of non-oxidative gas by means of surface coordination of long-chain aliphatic carboxylic acid and lithium titanate, thus the conductivity of lithium titanate can be improved and the high-rate and high temperature performances of lithium ion secondary battery can also be enhanced.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular to a preparation method of carbon-coated lithium titanate. Background technique [0002] With the low-carbon economy in the ascendant, lithium-ion batteries are actively developing in the direction of power vehicles and grid energy storage, and the development of lithium-ion batteries that can be quickly charged and discharged has become the focus of industry research. [0003] At present, most commercial lithium-ion batteries use carbon-based materials as negative electrodes. However, carbon-based negative electrode materials have many defects: for example, the formation of solid electrolyte interfacial film (SEI) during the first charge and discharge, resulting in irreversible capacity loss and insufficient rate performance. There are high temperature failure risks and safety risks. These problems make carbon-based materials unable to meet the needs of high-capacity, high-rate...

AI Technical Summary

Problems solved by technology

[0003] At present, most commercial lithium-ion batteries use carbon-based materials as negative electrodes. However, carbon-based negative electrode materials have many defects: for example, the formation of solid electrolyte interfacial film (SEI) during the first charge and discharge, resulting in irreversible capacity loss and insufficient rate performance. There are high temperature failure risks and safety risks, etc. These problems make carbon-based materials unable to meet the needs of high-capacity, high-rate power / energy storage batteries

[0005] Lithium titanate has good electrochemical energy and safety performance, and has broad application prospects in lithium-ion power batteries and energy storage systems that require high capacity and high rate. However, lithium titanate also has its own shortcomings: for example, ( 1) Low compaction density and low energy density; (2) Low electronic conductivity and large rate performance need to be improved; (3) Poor high temperature performance, etc.

Doping lithium titanate with 3d metal ions does help to improve the conductivity of the material, however, as the electrochemically inert dopant ions enter the lithium titanate lattice, the gram capacity of the material decreases

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