Preparation method of zirconium nitride coated lithium titanate composite material

Abstract

The invention discloses a preparation method for a zirconium nitride-coated lithium titanate composite material, relating to the field of a negative electrode material of a lithium ion battery. The preparation method comprises the steps of preparing lithium titanate precursor powder, performing high-energy ball grinding on zirconium powder, a lithium titanate precursor and an additive under inert atmosphere, and finally performing high-temperature sintering under nitrogen mixing atmosphere to realize synthesis of lithium titanate and nitridation reaction of surface zirconium. According to the zirconium nitride-coated lithium titanate composite material prepared by the preparation method disclosed by the invention, the zirconium nitride coating layer is high in uniformity, good in coating effect and high in conductivity; the problem of low conductivity of lithium titanate is solved; meanwhile, the problem of swelling of a battery of the lithium titanate system is effectively solved; the circulation stability of a lithium titanate negative electrode material is improved, and the cycle life of the battery is greatly prolonged; furthermore, the preparation process of the preparation method is simple and controllable; the coating degree of the zirconium nitride can be controlled by controlling technical parameters for preparing the zirconium nitride-coated lithium titanate composite material.

Description

technical field [0001] The invention relates to the field of negative electrode materials for lithium ion batteries, in particular to a preparation method of a zirconium nitride-coated lithium titanate composite material. Background technique [0002] In recent years, due to rising oil prices and serious global warming, low-carbon life has attracted more and more attention. Hybrid electric vehicles and pure electric vehicles have begun to enter people's lives; lithium-ion batteries are such power tools best candidate. However, for this type of power vehicle, the key issue of lithium-ion batteries is safety performance. Since the existing lithium-ion batteries usually use carbon materials as negative electrodes, their lithium intercalation potential is very close to that of metal lithium. It is easy to grow dendrite lithium on the surface of the negative electrode, which brings safety hazards. Moreover, the carbon negative electrode is easy to form an SEI film during the fi...

AI Technical Summary

Problems solved by technology

[0004] However Li 4 Ti 5 o l2 There are two deficiencies when it is directly applied to lithium batteries. One is the high resistivity of lithium titanate, and the other is that in the development of batteries, it is found that the lithium titanate power battery generally has the problem of flatulence, which seriously affects the performance of the battery.

Studies have shown that the crystallization water in the lithium titanate negative electrode material and the trace water in the electrolyte are difficult to remove. During the formation and cycle of the finished battery, these trace water will cause the electrolyte to decompose and generate gas, resulting in gas Swelling phenomenon, affecting battery life

At the same time, the study also found that the high-valent titanium in lithium titanate has strong catalytic activity, so it is easy to catalyze the decomposition of carbonate electrolyte to produce gas, which makes the battery cell flatulence

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