Composite externally-coated positive electrode material preparation method thereof, positive electrode and lithium ion battery

Abstract

The invention provides a composite externally-coated positive electrode material and a preparation method thereof, a positive electrode and a lithium ion battery. The composite externally-coated positive electrode material comprises positive electrode material particles, a composite coating layer is of a single-layer structure, at least part of an outer surface of the positive electrode material particle is coated with the composite coating layer, and the composite coating layer contains lithium, nickel, cobalt, manganese and boron elements. The composite externally-coated positive electrode material is advantaged in that a gas production problem is effectively improved, moreover, the composite coating layer optimizes the defects that a single coating layer is poor in conductive chemical performance, incomplete, low in capacity and first effect and the like, the firing temperature is reduced, and the residual alkali amount of a final product is reduced.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular, to a composite outer-coated positive electrode material and a preparation method thereof, a positive electrode and a lithium-ion battery. Background technique [0002] With its advantages of high specific energy, long cycle life, no memory effect, safety and reliability, and fast charging and discharging, lithium-ion batteries have become a bright spot in the research of new energy power supply technology. At present, they have been widely used in portable electronic products, and gradually Occupy the new energy vehicle power supply market. [0003] The ternary nickel-cobalt-manganese high-nickel cathode material has high specific energy and high working voltage. It has certain advantages in the field of lithium-ion batteries, but there are still some technical deficiencies, among which the problem of safe gas production is a more prominent problem. In response to th...

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Problems solved by technology

[0003] The ternary nickel-cobalt-manganese high-nickel cathode material has high specific energy and high working voltage. It has certain advantages in the field of lithium-ion batteries, but there are still some technical deficiencies, among which the problem of safe gas production is a more prominent problem. In response to this problem, material experts in the industry have carried out various coating modification studies on the existing high-nickel ternary cathode materials. These newly developed processes can partially solve the above problems, but there are also some shortcomings.

For example: Some processes cover rare earth elements and rare elements, which is difficult to achieve mass production; some processes have a high coating temperature, which is not suitable for cost control; some processes use multiple sintering and coating, and the operation is more complicated

Moreover, due to the common problem of high residual alkali in high-nickel ternary sintering, it is necessary to increase the process steps of water washing to remove residual alkali, which makes the preparation of ternary positive electrode materials extremely complicated.

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