Ternary cathode material for lithium ion battery and preparation method thereof

Abstract

The invention belongs to the field of electrochemical technique, and particularly relates to a ternary cathode material for a lithium ion battery and a preparation method of the ternary cathode material. The cathode material uses high-nickel nickel-cobalt lithium manganate or nickel-cobalt lithium aluminate as a basal body, and low-nickel lithium manganate is coated outside the basal body. A low-nickel ternary material is coated on the surface of a high-nickel ternary material, so that the pH and the content of residual alkali on the surface of the cathode material are reduced, the cathode material has processing performance of the low-nickel ternary material and specific capacity of the high-nickel ternary material, and the cycle performance of the cathode material can also be improved through the reduction of the surface basicity of the cathode material; and the high-nickel ternary material can be easily used in domestic enterprises, so that the invested cost of battery enterprises for using the high-nickel ternary material is greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, and in particular relates to a ternary cathode material for a lithium ion battery and a preparation method thereof. Background technique [0002] At present, the positive electrode materials used for lithium-ion batteries on the market mainly include lithium cobaltate, lithium manganate, lithium iron phosphate, lithium nickel-cobalt manganate and lithium nickel-cobalt aluminate. Due to its high compaction density, lithium cobalt oxide once became the overlord in the 3C field, but cobalt resources are scarce and the cost is very expensive; lithium manganese oxide is relatively cheap, but its energy density is low and its high temperature performance is poor. Low-end digital products; although lithium iron phosphate has excellent cycle performance, its low specific capacity has begun to limit its development; nickel-cobalt lithium manganate has high specific capacity and good cycle perform...

AI Technical Summary

Problems solved by technology

Due to its high compaction density, lithium cobalt oxide once became the overlord in the 3C field, but cobalt resources are scarce and the cost is very expensive; lithium manganese oxide is relatively cheap, but its energy density is low and its high temperature performance is poor. Low-end digital products; although lithium iron phosphate has excellent cycle performance, its low specific capacity has begun to limit its development; nickel-cobalt lithium manganate has high specific capacity and good cycle performance, and is considered to be a power battery The main positive electrode materials in the future, especially high-nickel-nickel-cobalt-manganese or nickel-cobalt-aluminum materials, with their ultra-high specific capacity and excellent cycle performance, are considered to be the first choice for lithium batteries in passenger cars. Nickel-cobalt-aluminum, as the cathode material of lithium batteries, once attracted widespread attention in China

[0003] However, due to the high nickel content, high pH, ​​and high residual alkali on the surface of high-nickel ternary materials, the conditions of battery manufacturers in the manufacturing process are quite harsh, which makes domestic battery companies unable to use or fail to achieve the expected performance after use. It also prevents high-nickel ternary materials from being widely used and promoted in China

[0004] At present, in order to reduce the surface alkalinity of high-nickel ternary materials, the surface pH and residual alkali are generally reduced by washing or wet-coating elements such as aluminum, magnesium, and titanium, but the process is complicated and the cost is high. The residual alkali is low, but it will increase its specific surface area, and the cycle performance and specific capacity will be greatly reduced. Although the coating of aluminum, magnesium, titanium and other elements can also reduce the surface residual alkali, it will not reduce the pH effect. , the processing performance of high-nickel ternary materials is not improved

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