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

Abstract

The invention provides a positive electrode active material, a positive pole piece, an electrochemical energy storage device and a new energy automobile. The positive electrode active material is LixNiyCozMkMepOrAm or LixNiyCozMkMepOrAm with a coating layer on the surface, the positive electrode active material is secondary particles, the particle size Dn10 of the positive electrode active material is greater than or equal to 0.5 mu m and less than or equal to 3 mu m, and the theoretical specific surface area BET1 and the real specific surface area BET2 of the positive electrode active material satisfy the condition that: 0.8<=(BET2-BET1) / BET1<=5.5 By reasonably controlling the particle morphology of the positive electrode active material and the quantity of the micro-powder in the positive electrode active material, the side reaction between the positive electrode active material and the electrolyte is effectively reduced, the gas production rate of the electrochemical energy storagedevice is reduced, and the energy density, the cycle performance and the rate capability of the electrochemical energy storage device are not deteriorated while the storage performance of the electrochemical energy storage device is improved.

Description

[0001] This application is a divisional application of the Chinese patent application (201811646958.2) submitted on December 29, 2018, and the description of the patent application is incorporated herein in its entirety by being incorporated in its entirety. technical field [0002] The present application relates to the technical field of energy storage devices, in particular to a positive electrode active material, a positive electrode sheet, an electrochemical energy storage device and a new energy vehicle. Background technique [0003] 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 tradi...

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.

[0004] 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 or washing with water to reduce the residual lithium content on the surface of the positive electrode active material. However, the above methods will cause damage to the performance of lithium-ion batteries. 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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