Preparation method of lithium battery high-voltage modified cathode material

Abstract

The invention provides a preparation method of a lithium battery high-voltage modified cathode material. A lithium battery made of the cathode material can be charged and discharged rapidly; the charging cut-off voltage is raised to 4.35V; and the energy density of the battery is greatly increased. In the cathode material prepared with the method, graphite is taken as a core, the surface of the graphite is uniformly coated with a layer of lithium titanate, and the surfaces of graphite particles coated with the lithium titanate are coated with a layer of conductive agent, thereby forming a graphite-lithium tianate-conductive agent three-layer composite structure. The obtained battery has high rapid charging-discharging performance, and the low-temperature performance is improved greatly. Meanwhile, the safety performance is improved greatly.

Description

technical field [0001] The invention relates to the field of lithium battery negative electrode materials, in particular to a method for preparing a fast-chargeable high-voltage lithium ion battery negative electrode material. Background technique [0002] Lithium-ion batteries have the characteristics of high specific capacity, small self-discharge, wide operating temperature range, high voltage platform, long cycle life, no memory effect, and environmental friendliness. They have been widely used in mobile phones, notebook computers, power tools and other fields. And gradually promote in the field of electric vehicles. At present, important cities such as my country's Beijing, Tianjin, Shenzhen, and Shanghai have built charging stations for hybrid electric vehicles and pure electric vehicles. However, according to the current charging method of lithium batteries, electric vehicles often need 7-8 hours for a single charge; while consumer electronics such as mobile phones, ...

AI Technical Summary

Problems solved by technology

[0003] In recent years, some studies have achieved the purpose of fast charging by setting a number of regular small holes on the positive electrode sheet, but the actual application of this method consumes more materials and time; some studies have used submicron lithium titanate and lithium metal oxide to coat graphite , Composite lithium metal oxide-coated graphite, graphite-coated lithium titanate and other materials are used as negative electrodes to achieve fast charging effects, but there are problems such as low energy density of lithium titanate and low conductivity of lithium metal oxide, while titanium The rate performance of lithium acid is poor, and the battery cell made is easy to produce gas, and the high temperature performance is poor

And the current research on fast charging shows that the charging cut-off voltage of the battery cell is only 4.2V, and the energy density is low.

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