Manganese-rich hydroxide precursor as well as preparation method and application thereof

Abstract

The invention provides a manganese-rich hydroxide precursor and a preparation method and application thereof, wherein the preparation method comprises the following steps: mixing a manganese salt, a cobalt salt and a nickel salt to obtain a mixed salt solution; mixing ammonia water, alkali liquor, an additive and the mixed salt solution to obtain a raw material solution; heating and stirring the raw material solution, and controlling the pH to obtain a precipitate; and sequentially washing and drying the precipitate to obtain the manganese-rich hydroxide precursor. According to the preparation method provided by the invention, nitrogen does not need to be introduced, so that the problem of fluctuation of the system volume and the liquid-solid contact area is avoided, the reaction slurry is stable, and the manganese-rich hydroxide precursor with uniform components can be obtained. Besides, the additive is added into the raw materials, so that oxidation of manganese by dissolved oxygen in the raw materials is avoided, and MnOOH is not generated in the synthesis process, so that the non-oxidation high-capacity manganese-rich hydroxide precursor can be obtained; meanwhile, bulk phase doping can be achieved, so that the rear-end doping procedures are reduced, and the doping uniformity is improved.

Description

technical field [0001] The invention relates to the technical field of cathode materials for lithium-ion batteries, and relates to a preparation method of a precursor, in particular to a manganese-rich hydroxide precursor and its preparation method and application. Background technique [0002] The capacity of lithium-rich manganese-based positive electrode materials prepared from manganese-rich hydroxide precursors is low. The main reason is that it is difficult to synthesize manganese-rich hydroxide precursors. Elements are prone to oxidation during precipitation, and the oxidized manganese element forms MnOOH, which is difficult to co-precipitate with the hydroxide of Ni or Co element, and it is difficult to form the solid solution type Li required for lithium-rich manganese-based positive electrode materials after sintering. 2 MnO 3 Phase, so the capacity is low. [0003] Oxidation of manganese is easy to occur in the preparation of manganese-rich hydroxides. The gener...

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Problems solved by technology

[0007] In the above prior art, non-oxidizing gases and additives are used to prevent high-valent manganese in an oxidized state. However, CN 110963533A does not discuss the type and dosage of additives and the effect achieved. CN 109860561A uses sodium borohydride to treat lithium-rich manganese. Manganese-based materials are doped, and the process of adding sodium borohydride and the doping effect achieved cannot effectively avoid the oxidation of Mn inside the precursor. In the method disclosed in CN 102646828A, the step of special reduction and activation cannot guarantee the oxidation and precipitation of manganese. not oxidized during