Preparation method of nickel cobalt lithium aluminate cathode material and lithium ion battery

Abstract

The invention discloses a preparation method of a nickel cobalt lithium aluminate cathode material and a lithium ion battery. The method comprises steps that a lithium salt and a tungsten source are added to the deionized water according to the molar ratio of Li:W=(1.8-2.2):(0.9-1.1) and stirred to obtain a treatment solution; a positive electrode material containing at least nickel cobalt lithiumaluminate is added to the treatment solution, mixed and stirred at the first specified temperature till the deionized water is completely evaporated to obtain an intermediate product; the intermediate product is dried; the dried intermediate product is sintered at the second specified temperature in the oxygen atmosphere and then cooled to the indoor temperature to obtain the positive electrode material containing the at least nickel cobalt lithium aluminate coated with lithium tungstate. The method is advantaged in that the rate, cycle and safety of the nickel cobalt lithium aluminate cathode material can be improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a preparation method of a nickel-cobalt-lithium-aluminate cathode material and a lithium-ion battery. Background technique [0002] Lithium-ion batteries have been widely used in 3C products, electric vehicles, energy storage and other fields. Especially with the rapid development of electric vehicles in recent years, the requirements for cathode materials are getting higher and higher. In order to achieve the goal of longer mileage for electric vehicles, it is required Lithium-ion batteries have higher energy density; ternary cathode materials nickel-cobalt lithium manganate or nickel-cobalt lithium aluminate have the advantages of high specific capacity and moderate price, which have attracted widespread attention and are considered to be the most promising lithium-ion batteries One of the positive electrode materials has become the preferred positive electrode ma...

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Problems solved by technology

[0004] Although the current conventional nickel-cobalt-lithium-aluminate material has a high energy density, strong side reactions will occur at the interface between the nickel-cobalt-lithium aluminate cathode material and the electrolyte during charging and discharging, which will increase the battery impedance and reduce the electrochemical performance. And the Li on its surface 2 CO 3 Decomposition and gas generation will occur, resulting in more prominent safety problems

[0005] In view of the above problems existing in nickel-cobalt lithium aluminate cathode materials, academia and the industry mainly improve the electrochemical performance and safety performance of lithium-ion battery cathode materials by selecting appropriate doping elements and coating elements, such as the Chinese invention patent Application CN201410183175.0 discloses a method for preparing a titanium oxide-coated multi-element positive electrode material, which improves the structural stability, energy Density and cycle performance, but the metal oxide coating layer has the problem of poor lithium ion conductivity, which reduces the rate performance of the positive electrode material; another example is the Chinese invention patent application CN201710752144.6 which discloses an indium oxide or tin-doped oxide An indium-coated positive electrode material and a preparation method thereof. The electronic conductivity of indium oxide is excellent, which improves the cycle performance of the material, but the ion conductivity of the coating layer is not good, which is not conducive to the transmission of lithium ions, which makes the rate performance of the positive electrode material decline

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