Lithium-ion battery ternary material coated with metal oxide on surface and preparation method thereof

Abstract

The invention discloses a ternary cathode material coated with metal oxide on the surface and used for a lithium ion battery, and a preparation method for the ternary cathode material. The preparation method comprises the following steps: step 1, adding soluble metal salt to a dispersant solution to enable the salt to be sufficiently dispersed evenly; step 2, adding a cathode material in a solution obtained in the step 1 for stirring for 1-5 h; step 3, adding an aqueous solution of an alkali metal hydroxide to a solution obtained in the step 2, adjusting the pH value of the solution to be 7-12, and carrying out filtering and drying to obtain a cathode material coated with metal oxide on the surface; step 4, performing heat treatment on the cathode material coated with metal oxide on the surface at the temperature of 400-700 DEG C to obtain the ternary cathode material coated with metal oxide on the surface. According to the preparation method for the ternary cathode material coated with metal oxide on the surface and used for the lithium ion battery, the method is simple, polyacrylamide is introduced as a dispersing agent and a flocculating agent, so that uniform coating of the ternary cathode material is realized, industrial production is facilitated, and the performance of the modified ternary cathode material is greatly improved.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and relates to a ternary positive electrode material for a lithium ion battery, in particular to a ternary positive electrode material for a lithium ion battery with a surface coated metal oxide and a preparation method thereof. [0002] technical background [0003] my country has put forward an energy requirement of 230 Wh / kg in 2015 for aerospace power applications. In addition, my country and Japan have formulated specific energy requirements higher than 200 Wh / kg in 2020 for power batteries for new energy electric vehicles. Target. To achieve these battery indicators, the development of cathode materials with specific capacity indicators higher than 220 mAh / g has become a top priority. Among the existing cathode materials, layered structure cathode materials are still the mainstream. The first generation layered material LiCoO 2 LiNiO has good electrochemical stability and excellent cyc...

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Problems solved by technology

[0005] Although lithium-rich manganese-based cathode materials have high discharge specific capacity, there are still many problems in practical applications of this type of material: (1) the first Coulombic efficiency is low; (2) the structural stability is poor; (3) the discharge voltage The platform gradually decreases; (4) Serious reaction with electrolyte under high voltage

[0006] At present, there are many reports on the coating modification methods of ternary cathode materials for lithium-ion batteries. Among various surface coating materials, metal oxides are a relatively common surface modification material with relatively simple coating methods. However, the current coating method is difficult to ensure the uniformity of the precipitation, and the particles are large, resulting in uneven surface coating, resulting in unstable capacity of the positive electrode material

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