Preparation method of lithium ion battery which contains modified lithium-manganese group-enriched anode active material and application thereof

Abstract

The invention provides a preparation method of lithium ion battery which contains modified lithium-manganese group-enriched anode active material and application thereof, and relates to the field of lithium ion battery technology, and the lithium ion battery cathode material containing the modified lithium-manganese group-enriched anode active material comprises the following components by mass: 86-95% of modified lithium-manganese group-enriched anode active materials, 3-6% of binders and 2-8% of conductive agents. The preparation method of the lithium-manganese group-enriched anode material is simple, and lithium ion battery employing the cathode material has the advantages of good cycle performance, non-attenuation capacity at high temperature, good low temperature performance, high discharge voltage platform, etc.

Description

Technical field: [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a preparation method and application of a lithium-ion battery of a modified lithium-rich manganese-based positive electrode active material. Background technique: [0002] Due to the advantages of high specific energy, long cycle life, good safety performance, environmental friendliness and no memory effect, lithium-ion batteries have been widely and rapidly used in mobile phones, notebook computers, digital cameras and other fields. Today, as fossil energy is increasingly depleted, people urgently need a power source with light weight, small size, wide operating temperature, good safety, low price and long life to drive vehicles. Among the many alternatives, lithium-ion batteries are highly favored. In the lithium battery family, lithium manganese oxide and lithium iron phosphate have become the main choices. However, these two materials also have many disadvant...

AI Technical Summary

Problems solved by technology

However, these two materials also have many disadvantages. For example, when the lithium manganese oxide battery is discharged, the volume of the unit cell expands, and over-discharge easily occurs in some areas on the surface of the positive electrode, resulting in a short cycle life, especially at high temperatures. Suitable for use in power batteries; the low electronic conductivity and low lithium ion migration rate of lithium iron phosphate materials lead to unsatisfactory electrochemical performance, such as low reversible discharge capacity, high rate can not be charged and discharged, poor low temperature performance and cycle capacity decay, In addition, the batch-to-batch stability of lithium iron phosphate materials is poor during preparation, and the consistency of batteries prepared using lithium iron phosphate is poor, thus limiting its further practical application.

[0003] In order to overcome the defects of poor cycle performance of lithium manganese oxide, serious high-temperature capacity loss, and poor low-temperature performance of lithium iron phosphate batteries, patent document CN 101694876 A discloses a lithium-rich manganese positive electrode active material, whose general formula is: Li[Li (1-2x) / 3 Ni x-a m y mn (2-x) / 3-b ]O 2 (M=Co, Al, Ti, Mg, Cu), where 0<x≤0.5, when M=Co, Al, 0<y<2x, a=b=y / 2; when M=Ti, 0 <y<(2-x) / 3, a=0, b=y; when M=Mg, Cu, 0<y<x, a=y, b=0

The specific surface area of ​​the material is 1-1.5m2 / g, the D50 particle size is 11.5±1um, the tap density>1.5g / cm3, and the pH is 8-12. The low-temperature performance of the lithium-rich manganese material is poor, and the discharge voltage platform is relatively low. Low level defects