Multistage reaction system, lithium ion multi-element positive electrode material precursor, preparation method of lithium ion multi-element positive electrode material precursor and preparation method of lithium ion multi-element positive electrode material

Abstract

The invention provides a multistage reaction system, a lithium ion multi-element positive electrode material precursor, a preparation method of the lithium ion multi-element positive electrode material precursor and a preparation method of a lithium ion multi-element positive electrode material. According to the multi-stage reaction system provided by the invention, two stages of reaction kettlesare arranged, a circulating device is arranged between the two stages of reaction kettles, the multi-element positive electrode material precursor prepared by the system and the preparation method iscontrollable and uniform in particle size, regular in morphology and high in tap density, and the structural stability of the positive electrode material can be improved; the primary particle interlayer spacing of the positive electrode material precursor is reduced, the specific surface area of the material is increased, and the tap density of the material is improved; and meanwhile, the processreduces the interface internal resistance of the positive electrode material in the circulation process, so that the electrochemical performance, especially the circulation performance and the rate capability, of the material are improved, the energy density of the lithium ion battery is improved, and the process is suitable for industrial batch production.

Description

technical field [0001] The invention relates to the field of lithium ion battery materials, in particular to a multi-stage reaction system, a lithium ion multi-element positive electrode material precursor and a preparation method thereof, and a preparation method of the lithium ion multi-element positive electrode material. Background technique [0002] As a secondary battery, lithium-ion batteries have been maturely commercialized in the field of small power batteries such as 3C electronic products, mobile power supplies, power tools and electric bicycles. The cathode materials used mainly include lithium iron phosphate, lithium manganate, and lithium cobalt oxide. And ternary materials, etc., the actual specific capacity is lower than 200mA h / g. With the change of the global energy pattern and the limited supply of nickel-cobalt-manganese resources, lithium-rich manganese-based cathode materials with high specific capacity (>250 mA h / g) and low cost have attracted exte...

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Problems solved by technology

[0004] However, subject to the strict production conditions of this process, there are shortcomings such as the growth of early crystal particles is too fast and too large, the particle size distribution of the final prepared precursor particles is wide, and the particle tap density is low.

For example, CN108054371A discloses a preparation method of a lithium-rich manganese-based positive electrode material, and adopts a co-precipitation method to prepare a precursor of a lithium-rich manganese-based material. However, the precursors obtained by the co-precipitation method have the above-mentioned problems (the particle size distribution is wide, low tap density, poor electrochemical performance, etc.), and subsequent hydrothermal treatment is required to adjust the particle microstructure in order to improve the electrochemical performance, which makes the process complicated, increases the cost, and the improvement effect is not good

In recent years, many methods have focused on the synthesis process of the precursor of the multi-component cathode material, but there are situations where the precursor process is uncontrollable or difficult to control after the scale-up of the precursor process, thus limiting the performance improvement space of the subsequent finished cathode material

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