Preparation method of modified positive electrode material, and lithium ion battery

Abstract

The invention provides a preparation method of a modified positive electrode material, and a lithium ion battery. The preparation method of the modified positive electrode material comprises the stepsof performing mixing on a layered positive electrode active material, acid with the boiling point of not higher than 600 DEG C and / or acidic salt of the acid with the boiling point of not higher than600 DEG C, and heating to a temperature higher than the boiling point temperature or the sublimation temperature of the acid, or heating to a temperature higher than the decomposition temperature, the boiling point temperature or the sublimation temperature of the acidic salt and performing heat treatment to change the acid and / or the acidic salt into a vapor state to be reacted with residual alkali on the surface of the layered positive electrode active material so as to lower the content of the residual alkali to obtain the modified positive electrode material. After the modified positive electrode material obtained by the method is applied to the lithium ion battery, gas production of the lithium ion battery can be lowered, and the service life of the lithium ion battery is prolonged.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a preparation method of a modified positive electrode material and a lithium ion battery. Background technique [0002] Lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and military communications because of their advantages such as high specific energy, good cycle performance, small self-discharge, and no memory effect. Lithium-ion battery cathode material is a key material that affects battery performance and cost. At present, the cathode materials of lithium-ion batteries mainly include spinel materials, polyanion materials and layered materials. Layered materials, especially high-nickel layered cathode materials have attracted extensive attention due to their high specific capacity. [0003] With the increase of nickel content in layered cathode materials, the surface structure is gradually unstable, and lithium ions are easily de...

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Problems solved by technology

However, this method uses a high-temperature secondary sintering process, which is likely to cause damage to the crystal surface structure of the positive electrode material, thereby affecting the performance of the electrochemical performance.

Another example is the Chinese patent document CN201410191376.5 applied on May 7, 2014. The organic solvent is one or more of ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and propylene carbonate. Although this method can reduce the residual alkali on the surface of the positive electrode material to a certain extent, this method is expensive, and the organic solvent volatilizes seriously, which is harmful to the human body.

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