A kind of lithium-ion battery composite coated cathode material and preparation method thereof

Abstract

The invention provides a compound cladding positive pole material of a lithium ion battery and a preparation method of the compound cladding positive pole material. The positive pole material comprises a positive pole material base body and a cladding layer, wherein the cladding layer comprises two parts: a metal oxide main body framework layer with a porous three-dimensional structure, a surface layer distributed on the main body framework layer and a rapid ion conductor layer located in a pore. The compound cladding layer produced by the method has a relatively large and controllable specific surface area, and the contact between the cladding layer and electrolyte can be effectively improved, and the rate performance of the material can be effectively improved; meanwhile, the compound cladding layer has good chemical stability, and a contact side reaction between the positive pole material base body and the electrolyte is inhibited; and meanwhile, the damages to the surface cladding layer of the material, caused by the deformation in a rolling process of a pole piece, and the tension change of the cladding layer in a circulating process are inhibited; and the degradation of the positive pole material in the circulating process can be effectively improved and the circulating stability of the battery is improved.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries, in particular to a lithium-ion battery composite coated cathode material and a preparation method thereof. Background technique [0002] As a new type of secondary battery, lithium-ion battery has the characteristics of high specific capacity, high voltage and good safety, and has been widely used in portable electronic products. Commonly used cathode materials for lithium-ion batteries include lithium cobalt oxide, lithium nickel cobalt oxide, lithium nickel cobalt manganese oxide, and lithium manganese oxide. Conventional cathode materials for lithium-ion batteries face a problem in the charged state: they are highly oxidizing to the electrolyte and are easy to react with the electrolyte. ACCIDENT. Therefore, surface coating treatment is required for these materials. Coating a layer of non-electrochemically active material on the surface of the positive electrode material prevents direct...

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Problems solved by technology

Conventional cathode materials for lithium-ion batteries face a problem in the charged state: they are highly oxidizing to the electrolyte and are easy to react with the electrolyte. ACCIDENT

However, this method also has obvious defects. On the one hand, the metal oxide coating layer is relatively dense, and the contact with the electrolyte is not good, which affects the performance of the material rate performance; the uniformity of the fast ion conductor material and the metal oxide coating cannot be guaranteed, and the control method is difficult. On the other hand, the positive electrode material after coating is easily broken by force during the rolling process of the pole piece, causing the surface of the coating layer to be broken and affecting the coating effect

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