Multi-layer aluminum-doped nickel-cobalt-manganese precursor and preparation method thereof

Abstract

The invention provides a multi-layer aluminum-doped nickel-cobalt-manganese precursor which is of a core-shell structure, an aluminum-undoped nickel-cobalt-manganese hydroxide serves as an inner core, the surface of the inner core is sequentially coated with an aluminum-doped nickel-cobalt-manganese hydroxide layer and an aluminum-undoped nickel-cobalt-manganese hydroxide layer which are of an alternating structure, and the aluminum-doped nickel-cobalt-manganese hydroxide layer is arranged on the outermost layer of the nickel-cobalt-manganese precursor. The preparation method comprises the following steps: adding ammonia water as a reaction base solution into a reaction kettle, introducing nitrogen, starting stirring, adding a metal salt mixed solution, a precipitator and a complexing agent into the reaction kettle in a parallel flow manner, and reacting until the particle size of generated particles reaches the particle size of the inner core; introducing a sodium metaaluminate solution, and generating the aluminum-doped nickel-cobalt-manganese hydroxide layer on the surface of the inner core; stopping introducing the sodium metaaluminate solution, and generating the aluminum-undoped nickel-cobalt-manganese hydroxide layer on the surface of the aluminum-doped nickel-cobalt-manganese hydroxide layer; and repeating the steps until the multi-layer aluminum-doped nickel-cobalt-manganese precursor with the designed structure is generated. The nickel-cobalt-manganese precursor has relatively good thermal stability and structural stability.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a multilayer aluminum-doped nickel-cobalt-manganese precursor and a preparation method thereof. Background technique [0002] Compared with other traditional secondary batteries, lithium-ion batteries are widely used in 3C electronic products and electric vehicles due to their advantages such as high energy density, long cycle life, and environmental protection. Nickel-cobalt-manganese ternary cathode materials have become the most promising cathode materials for lithium-ion batteries due to their high reversible capacity, long cycle performance and high operating voltage. The increase of nickel content further improves the capacity of existing nickel-cobalt-manganese ternary cathode materials, but excessive nickel enrichment will lead to a decrease in cycle performance and deterioration of thermal stability, which poses a safety hazard. At present, in order to e...

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Problems solved by technology

[0003] Chinese patent CN107316990A discloses a method for preparing an aluminum hydroxide-coated nickel-cobalt positive electrode material precursor, which first synthesizes a spherical nickel-cobalt hydroxide core in a reactor, and then coats a layer of aluminum hydroxide on the surface of the core, although Aluminum coating can inhibit the exothermic reaction during charge and discharge and improve structural stability, but the aluminum hydroxide shell itself does not provide effective capacity, and a certain thickness of the shell will hinder the deintercalation of lithium ions in the positive electrode material.

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