Preparation method and product of surface modified lithium battery high-nickel positive electrode material

Abstract

The invention belongs to the field of secondary lithium ion batteries, and discloses a preparation method of a surface modified lithium battery high-nickel positive electrode material. The preparation method comprises the following steps: putting high-nickel positive electrode material into a reaction cavity of an atomic layer deposition system, and vacuumizing the reaction cavity for 5 to 10 s, so that the temperature of the reaction cavity is 140 to 160 DEG C; introducing a reaction source so that the pressure of the reaction cavity reaches 5 to 8 mbar; introducing N2 to take away redundant reaction source in the reaction cavity; introducing water to react with the reaction source, and carrying out surface deposition on the high-nickel positive electrode material to obtain an oxide film; introducing N2 to take away redundant water in the reaction cavity; and repeating the above steps to obtain the surface modified lithium battery high-nickel positive electrode material. The invention also provides the surface modified lithium battery high-nickel positive electrode material prepared by the method, and a positive electrode piece and a lithium ion secondary battery prepared from the material. The positive electrode material has the advantages of simple and practicable preparation method, easily controlled thickness for a cladding layer and the like, and is applicable for large-scale production.

Description

technical field [0001] The invention belongs to the field of secondary lithium ion batteries, and more specifically relates to a preparation method and product of a surface-modified lithium battery high-nickel cathode material. Background technique [0002] With the continuous progress of society and the rapid growth of the global economy, products brought about by the continuous development of science and technology play an indispensable role in people's lives. Electronic products, electric vehicles, medical equipment, etc. The requirements are getting higher and higher, people's demand for energy is increasing, and the understanding of the importance of sustainable social and economic development is deepening. Lithium-ion battery, as a new generation of green high-energy rechargeable battery, has achieved rapid development in the past 20 years due to its outstanding advantages such as high voltage, high energy density, good cycle performance, small self-discharge and envir...

AI Technical Summary

Problems solved by technology

[0003] However, further studies have shown that in lithium-ion batteries, due to the high potential of the positive electrode material and the strong oxidation of the positive electrode material in the delithiated state, it is easy to have side reactions with the organic electrolyte, which deteriorates the performance of the battery.

Although the nickel-based cathode material LiNiO 2 Due to the advantages of high discharge specific capacity and low price, however, some inherent defects limit its wide application: such as stoichiometric LiNiO 2 Difficult to synthesize, there are more heterogeneous phase transitions in the discharge process, Ni 2+ Occupy Li + The 3a position leads to mixed cations, high nickel content, strong catalytic activity at the end of charging, easy to catalyze electrolyte decomposition, poor room temperature and storage performance. In addition, high nickel positive electrode materials have low first-cycle efficiency during charge and discharge. During the cycle, the structure changes from a stable layered structure to an unstable rock-salt phase, resulting in poor cycle performance

[0004] Due to the above defects and deficiencies, there is an urgent need in this field to further improve and improve the high-nickel cathode material to solve the problem of poor cycle performance in the charging and discharging process.

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