Method for preparing carbon-coated manganese-doped lithium titanate negative electrode material of lithium ion battery

Abstract

The invention relates to a method for preparing a carbon-coated manganese-doped lithium titanate negative electrode material of a lithium ion battery. In the method, the amount of doped manganese and experimental conditions are controlled; lithium salt, manganese dioxide or manganese tetroxide, titanium dioxide and sugar or glucose are used as raw materials; and the raw materials are put in a ball mill for ball milling, and are dried and sintered to obtain a carbon-coated manganese-doped lithium titanate composite material. In the method, carbon coating is performed on the doping inside lithium titanate cells and the outside of grains by using manganese ions and the lithium titanate is modified simultaneously, so the electrical conductivity of the lithium titanate is greatly improved, the cyclical stability and the reversible capacity of large currents are obviously improved, and the performance requirements of the negative electrode material of a power lithium ion battery are met. The method has a simple preparation process and is easy to realize industrialization; and the carbon-coated manganese-doped lithium titanate composite material obtained by the method has excellent electrochemical performance, realizes the optimal combination of the maximum reversible circulation capacity and the optimal high electrical conductivity, and can be applied to high-power lithium ion batteries.

Description

technical field [0001] The invention belongs to the technical field of preparation of electrochemical power source materials, in particular to a carbon-coated manganese-doped lithium titanate (Li 4-x mn x Ti 5 o 12 / C) (0.1≤x≤0.2) preparation method. It has broad application prospects in the field of commonly used secondary lithium ion batteries and power energy battery anode materials. Background technique [0002] With the development of power batteries, lithium-ion power batteries have gradually become mainstream products. Lithium-ion battery anode materials mainly include carbon-based materials, nitrides, silicon-based materials, tin-based materials, various new alloys, etc. Among them, carbon-based materials have been used in practice, and other materials are mostly in the laboratory research stage. Although carbon anode materials have been greatly improved in terms of safety performance and cycle performance, there are still many disadvantages: the potential of ca...

AI Technical Summary

Problems solved by technology

Although carbon anode materials have been greatly improved in terms of safety performance and cycle performance, there are still many disadvantages: the potential of carbon materials is very close to that of metal lithium, and when the battery is overcharged, lithium will be on the surface of the carbon electrode. Lithium dendrites are formed due to precipitation, which causes short circuit; the first charge and discharge efficiency is low, and it is easy to react with the electrolyte; there is obvious voltage hysteresis; the uneven charging platform needs to be equipped with anti-overshoot devices and thermal runaway at high temperatures, etc.

[0005] But pure phase Li 4 Ti 5 o 12 Has the following disadvantages: low electronic conductivity, only 10 -9 S / cm, when charging and discharging at a high rate, the capacity decays quickly

Its main disadvantages: high cost of organic compounds; low output; a large amount of organic gas is volatilized; it is difficult to realize industrialization

[0009] However, the doped lithium titanate that has been achieved either reduces the reversible specific capacity or cycle stability, and the increase in conductivity is not obvious

Thus limiting the practical application of lithium titanate

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