Coated lithium nickel cobalt manganese oxide positive electrode material, preparation method thereof and lithium ion battery

Abstract

The invention discloses a coated lithium nickel cobalt manganese oxide positive electrode material, a preparation method thereof and a lithium ion battery. The preparation method comprises the following steps of: mixing a lithium nickel cobalt manganese oxide material with an ammonia-ammonia chloride buffer solution, then slowly adding a sodium metaaluminate solution, and stirring for reaction to prepare a precursor material; and washing the precursor material, drying the precursor material at the temperature of 110-130 DEG C, and sintering the precursor material in an oxygen atmosphere at the temperature of 300-500 DEG C. According to the invention, sodium metaaluminate is used as a coating source, and an ammonia-ammonia chloride buffer solution is used for adjusting the pH value, so that Al (OH) 3 precipitate can be uniformly separated out, a coating layer is deposited on the surfaces of particles, finally, the positive electrode material with primary particles of a nanosheet structure is formed through sintering, the nanosheet structure provides a shorter ion channel for lithium ion transmission, so that the lithium deposition problem and the particle crushing problem in the rapid charging process are relieved, and the performance of the lithium battery is improved.

Description

technical field [0001] The invention relates to the technical field of battery positive electrode materials, in particular to a coated nickel-cobalt lithium manganese oxide positive electrode material, a preparation method thereof, and a lithium ion battery. Background technique [0002] The nickel-cobalt lithium manganate ternary material will irreversibly react with the electrolyte on the surface of the positive electrode material during the charge-discharge cycle, and fluoride corrosion and transition metal ion dissolution will occur on the surface of the positive electrode active particles, resulting in the collapse of the material structure and improving the cycle performance. deterioration. In order to improve the cycle performance and rate performance of the battery, the method of surface coating is generally used to mechanically isolate the active material and the electrolyte to stabilize the material structure. [0003] In the current preparation methods, wet or dr...

AI Technical Summary

Problems solved by technology

[0003] In the current preparation methods, wet or dry methods are often used to uniformly coat a layer of Al on the surface of the positive electrode material particles. 2 o 3 cladding layer, in the prior art, the method of spray drying is used to prepare Al 2 o 3 Coated nickel cobalt lithium manganate cathode material, but the impurity ions introduced in this method will lead to a decrease in cycle performance

In addition, existing coated Al 2 o 3 The formed positive electrode material usually has a spherical particle structure, and the fast charging of high energy density batteries is limited by the conductivity of the electrode and the ion transport performance. Spherical particles are prone to particle cracking and structural damage during the rapid charge and discharge process, resulting in a decrease in cycle performance.

Images