Lithium-rich multi-element positive electrode material, preparation method thereof, positive electrode and lithium ion power battery

Abstract

The invention provides a preparation method of a lithium-rich multi-element positive electrode material, which comprises the following steps: A) mixing a nickel-containing multi-element precursor witha primary lithium source, and presintering a mixture to obtain an intermediate; and the primary lithium source including one or more selected from lithium carbonate, lithium hydroxide, lithium fluoride and lithium nitrate; and B) mixing the intermediate, a secondary lithium source and an additive, and carrying out secondary sintering to obtain the lithium-rich multi-element positive electrode material, and the secondary lithium source including one or more selected from lithium carbonate, lithium hydroxide, lithium fluoride and lithium nitrate. The ratio of the total amount of substance of the primary lithium source and the secondary lithium source to the amount of substance of the nickel-containing multi-component precursor is (1-2): 1; wherein the molar ratio of the primary lithium source to the secondary lithium source is (1-9): (9-1); the lithium-rich multi-element positive electrode material has a chemical formula shown as a formula I: Li < 1 + x > Ni Co Mn < c > M <d > O < 2 >. The invention also provides the lithium-rich multi-element positive electrode material, a positive electrode and a lithium ion power battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium-rich multi-component positive electrode material, a preparation method thereof, a positive electrode and a lithium ion power battery. Background technique [0002] Power lithium-ion batteries have become the core of new energy vehicles. With people's pursuit of battery life, the development of a 300Wh / Kg battery system has attracted people's attention. Cathode materials play a vital role in lithium-ion batteries. In order to meet the market demand for the cruising range of electric vehicles, to improve the overall energy density of lithium-ion batteries, it is of great significance to study high-performance cathode materials. Multi-element materials, including lithium-rich manganese-based cathode materials, are potential candidate cathode materials for long-life lithium-ion batteries due to their high energy density. [0003] The above-mention...

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Problems solved by technology

There are also certain disadvantages in multi-element lithium-rich cathode materials; one is that a large amount of gas is released during the sintering process when the lithium content is high, which affects the stable atmosphere during the sintering process and leads to unstable electrochemical performance of the material. Second, the use of carbonic acid Lithium is used as a lithium salt and the prefabricated precursor is mixed with lithium for sintering. Since the carbonate is usually relatively fluffy, the precursor has a lower tap density and lower compaction density; third, a large amount of carbon dioxide escapes during the later sintering process, so the material can only be selected Only a low filling amount can ensure the stable performance of the electrochemical performance of the material. Fourth, too much lithium salt will lead to serious agglomeration of the material with too high temperature during the sintering process, which is not conducive to the exertion of the material energy density of the positive electrode material and the post-processing of the material. performance

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