Preparation method of atomic layer deposition coated high-nickel ternary positive electrode material

Abstract

The invention discloses a method for coating a high-nickel ternary positive electrode material by atomic layer deposition. The method mainly solves the problems that the performance of the lithium battery is reduced, the performance of the lithium battery can be improved through positive electrode material wrapping, and existing carbon material wrapping is poor in interface stability and falls offafter being used for a period of time. An existing method for wrapping an oxide with a positive electrode material is complex in process and high in cost, and has the problem that waste liquid needsto be treated subsequently. The preparation method is characterized by comprising the following steps: heating, depressurizing, introducing a precursor A, introducing gas to clean a reaction chamber,introducing a precursor B, introducing gas to clean the reaction chamber, and repeating the reaction steps to obtain a coating layer with a certain thickness. The method has the advantages that the coating layer is uniform, the generated coating layer is a metal oxide and is relatively stable, the cycle stability and the capacity stability of the battery are improved, no waste liquid is generatedin the production process, the method is environment-friendly, the cost for waste liquid treatment is reduced, and the thickness of the coating layer is changed by controlling the cycle number.

Description

technical field [0001] The invention relates to the technical field of new energy, in particular to a method for preparing an atomic layer deposition-coated high-nickel ternary positive electrode material. Background technique [0002] Lithium batteries are currently the main source of power for electric vehicles, mobile phone batteries and other devices that can be repeatedly charged and discharged. High-capacity batteries play a decisive role in improving the cruising range of vehicles and the standby time of mobile phones, while the capacity of positive electrode materials is the current limitation. Key material for battery capacity. Therefore, in recent years, the country has vigorously accelerated the development of high-capacity secondary batteries to promote the development of the automobile industry. The problem of battery capacity is also one of the main problems in the mobile phone, tablet, and notebook computer industries. [0003] At present, the high-nickel ter...

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Problems solved by technology

[0003] At present, the high-nickel ternary cathode material is a potential high-capacity battery. Compared with the common cathode materials on the market, the high-nickel cathode material has the advantage of higher charge-discharge specific capacity, but it has cycle stability and capacity stability. Relatively poor, the capacity of the battery decays rapidly, making it unable to meet the problem of commercialization. The main reason is that in lithium-ion batteries, due to the high potential of the positive electrode material, when lithium ions are extracted, the positive electrode material has a strong oxidation. It is easy to react with the electrolyte, resulting in a decrease in the performance of the battery. The high reactivity of high-nickel materials makes the capacity unstable, and the side reactions that occur when used as battery materials also reduce the safety of the battery.

[0004] Aiming at the problem of unstable capacity and low safety of ternary materials as the positive electrode of the battery, the current approach is to wrap the positive electrode of the battery made of high-nickel materials, and the strong oxidizing lithium released through the wrapping layer The ions are isolated from the positive electrode material to avoid oxidation of the high-nickel ternary material to improve the cycle stability of the battery. The atomic layer deposition technology is used to make the oxide coating layer on the surface of the high-nickel ternary material uniform and stable. The material that is mixed evenly and sintered at high temperature has the advantages of greatly improving the thickness, uniformity, and stability of the coating layer. The high-nickel ternary material wrapped with carbon material is widely used because of its low cost, but carbon material and ternary oxide The difference is large, the interface stability is difficult to solve, and there is a problem that the carbon coating layer falls off after a period of use. The main metal components of organic metal compounds include titanium, aluminum, magnesium, zirconium, etc., and the ionic radius of nickel, cobalt, and manganese Similarly, after the oxide is formed, the structure is more similar to the surface structure of the high-nickel ternary material, which makes the formed compound more stable and enhances the stability, and solves the problem that the coating layer falls off and loses its function after a period of use. There are other methods of wrapping oxides with positive electrode materials, but the solution processing process is complicated, the cost is high, and there are problems of post-processing and waste liquid treatment. The raw material for forming the oxide wrapping layer is an organic metal oxide. For the metal oxide layer prepared by the secondary molten salt method of oxides, it has the advantage of not needing to deal with a large amount of waste liquid generated in the secondary molten salt method, avoiding subsequent environmental pollution and the cost of waste liquid treatment; The atomic layer deposition technology used in the invention achieves thickness control by controlling the number of reactions

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