Lithium-rich manganese-based precursor and preparation method thereof, and lithium-rich manganese-based positive electrode material and preparation method thereof

Abstract

The invention belongs to the field of lithium batteries, and provides a preparation method of a lithium-rich manganese-based precursor, which comprises the following steps: S1, solution preparation: respectively preparing a transition metal salt solution, an alkaline solution, a complexing solution A and a complexing solution B; S2, coprecipitation reaction: separately slowly adding the transition metal salt solution and the alkaline solution prepared in the step S1 into a reaction kettle for reaction, slowly adding the complexing solution A into the reaction kettle at the first stage of the reaction, and slowly adding the complexing solution B into the reaction kettle at the second stage of the reaction; and S3, post-processing. According to the method, the precursor material which is smooth in particle surface, good in sphericity degree, good in particle compactness and uniform in particle size distribution can be synthesized, and an ammonia-containing complexing agent is not used in the synthesis process. The invention also provides the lithium-rich manganese-based precursor prepared by the method, a lithium-rich manganese-based positive electrode material prepared from the precursor and a preparation method of the lithium-rich manganese-based positive electrode material.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a lithium-rich manganese-based precursor and a preparation method thereof, a lithium-rich manganese-based cathode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in various fields from 3C electronic products to electric vehicles due to their light weight, high energy density, no memory effect, long cycle life and environmental friendliness. With the development of the times, people's demand for higher capacity and safer lithium-ion batteries is increasing. Lithium-rich manganese-based cathode materials are considered to be the most promising cathode materials for next-generation lithium-ion batteries because of their ultra-high discharge specific capacity >250mAh g-1, low cost, non-toxicity, and high thermal stability. [0003] Preparation of lithium-rich manganese-based cathode material precursors by co-precipita...

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Problems solved by technology

However, when the inventors synthesized the lithium-rich manganese-based precursor using the composite complexing agent in the above-mentioned patent, they found that the surface of the prepared material particles was rough, the sphericity was poor, the particle compactness was poor, and the particle size distribution was uneven, which led to the prepared material. Poor electrochemical performance of cathode materials

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