Preparation method of magnesium doped lithium titanate composite material for lithium ion battery

Abstract

The invention discloses magnesium doped lithium titanate composite material for a lithium ion battery and a preparation method thereof. The method comprises the following steps of: mixing lithium oxalate, titanium dioxide, magnesium hydroxide and dysprosium oxide, ball-milling the mixture, and carrying out flash evaporation to obtain a nanometer precursor; evenly mixing phenolic resin, ethylene glycol and benzene sulfonyl chloride to prepare a mixture, carbonizing the mixture to obtain porous carbon material with an average pore size of less than 300 nm; and ball-milling and sintering the dried precursor and the porous carbon to obtain the magnesium doped lithium titanate composite material. The magnesium doped lithium titanate composite material for the lithium ion battery of the invention especially is added with Dy (dysprosium) for modification, the surface of the composite material is coated by specially prepared porous carbon, and when the composite material is used for a lithium ion battery, the composite material has relatively high energy density and good circulation stability, thus the lithium ion battery has high specific capacity and relatively long service life.

Description

Technical field [0001] The invention relates to a battery electrode material, in particular to a magnesium-doped lithium titanate composite material for lithium ion batteries and a preparation method thereof. Background technique [0002] As a new type of chemical power source, lithium-ion batteries have become the focus of development in the field of new energy materials in countries around the world due to their high output voltage, high specific energy, long cycle life, low self-discharge, safety, no memory effect and environmental friendliness . , Lithium-ion battery anode materials mainly include carbon-based materials, nitrides, silicon-based materials, tin-based materials, various new alloys and so on. Among them, the actual application is mainly carbon-based materials, and other materials are mostly in the laboratory research stage. [0003] Although carbon anode materials have been greatly improved in terms of safety performance and cycle performance, there are still man...

AI Technical Summary

Problems solved by technology

[0003] 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 precipitated and formed, 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.

In addition, the ionization tendency of metallic magnesium is relatively large, and the amount of electricity per unit volume that can be obtained through redox reactions is large.