Positive electrode active material, positive pole piece and electrochemical energy storage device

Abstract

The application provides a positive electrode active material, a positive electrode sheet and an electrochemical energy storage device. The positive electrode active material is Li x Ni y co z m k Me p o r A m or Li with a cladding layer on the surface x Ni y co z m k Me p o r A m , the positive electrode active material is single crystal or single crystal-like particles, and the particle size D of the positive electrode active material n 10 Satisfied: 0.3μm≤D n 10≤2μm. This application effectively reduces the side reaction between the positive electrode active material and the electrolyte by reasonably controlling the particle morphology of the positive electrode active material and the amount of micropowder in the positive electrode active material, reduces the gas production of the electrochemical energy storage device, and can improve the electrochemical performance of the electrochemical energy storage device. The storage performance of the energy storage device does not deteriorate the energy density, cycle performance and rate performance of the electrochemical energy storage device.

Description

technical field [0001] The present application relates to the technical field of energy storage devices, in particular to a positive electrode active material, a positive electrode sheet and an electrochemical energy storage device. Background technique [0002] With the escalation of energy crisis and environmental problems, the development of new green energy is imminent. Lithium-ion batteries have been widely used in various fields due to their advantages such as high specific energy, wide application temperature range, low self-discharge rate, long cycle life, good safety performance, and no pollution. At the same time, lithium-ion batteries are used as energy systems. The replacement of traditional diesel locomotives by new energy vehicles has also been gradually tried around the world. However, currently commonly used cathode active materials, such as lithium iron phosphate (LiFePO 4 ), low-nickel ternary materials (LiNi 1 / 3 co 1 / 3 mn 1 / 3 o 2 ), etc., due to the ...

AI Technical Summary

Problems solved by technology

However, currently commonly used cathode active materials, such as lithium iron phosphate (LiFePO 4 ), low-nickel ternary materials (LiNi 1 / 3 co 1 / 3 mn 1 / 3 o 2 ), etc., due to the limitations of the nature of the material itself, it cannot fully meet the energy density requirements of lithium-ion batteries, and increasing the nickel content of ternary materials can increase the energy density of lithium-ion batteries. Therefore, high-nickel ternary materials are the current lithium-ion battery One of the main research objects of battery cathode active materials

However, as the nickel content increases, the side reaction between the ternary material and the electrolyte is also significantly intensified, which will lead to serious gas production in lithium-ion batteries, which is one of the biggest bottlenecks in the mass production and commercialization of high-nickel ternary materials.

[0003] At present, at the material level, the means to improve the gas production of lithium-ion batteries mainly include reducing the content of nickel in the ternary material, washing with water, etc. to reduce the residual lithium content on the surface of the positive electrode active material. Different degrees of damage, for example, the reversible gram capacity of the lithium-ion battery is reduced, the cycle performance is deteriorated, etc.

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