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Core-shell structure high nickel gradient nickel cobalt manganese aluminum quaternary positive electrode material and preparation method thereof

A core-shell structure and positive electrode material technology, which is applied in the field of lithium battery positive electrode materials and its preparation, can solve the problems that can not reflect the improvement of adding aluminum, complex synthesis process, difficult to control, etc.

Active Publication Date: 2019-11-29
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method does not clearly indicate the electrochemical performance of the positive electrode material before coating, and the improvement of the material by adding aluminum cannot be reflected after coating and modification with graphene, and the hydrothermal reaction conditions are relatively high, difficult to control, and the synthesis process is relatively complicated.
[0004] CN 106920934 A discloses a method for preparing cobalt-aluminum co-doped modified ternary precursor and positive electrode material based on high-nickel material, mixing nickel-cobalt-aluminum mixed solution, ammonia water and sodium hydroxide solution in a heating reaction kettle to generate The coprecipitation reaction obtains a kind of cobalt-aluminum co-doping modified ternary precursor precursor based on high-nickel material, because the material prepared by this method takes lithium nickelate as the leading material, and it is inevitable that the nickel content is often higher than the lithium content ( Li 1-x Ni 1+x o 2 ), so divalent nickel will always appear in the lithium layer, resulting in a decrease in the lithium ion diffusion coefficient of the material

Method used

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  • Core-shell structure high nickel gradient nickel cobalt manganese aluminum quaternary positive electrode material and preparation method thereof
  • Core-shell structure high nickel gradient nickel cobalt manganese aluminum quaternary positive electrode material and preparation method thereof
  • Core-shell structure high nickel gradient nickel cobalt manganese aluminum quaternary positive electrode material and preparation method thereof

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Embodiment 1

[0063] This embodiment includes the following steps:

[0064] (1) Under stirring conditions, 2 L low-nickel solution (a mixed solution of nickel sulfate, cobalt sulfate, manganese sulfate and aluminum sulfate, wherein the molar ratio of Ni, Co, Mn, and Al ions is 7:1:1.4:0.6 , the total molar concentration of Ni, Co, Mn, Al is 2.0 mol / L) with the feed rate of 50mL / h, pump into 2 L high-nickel solution (the mixed solution of nickel sulfate and cobalt sulfate, wherein, Ni, Co ion The molar ratio is 9:1, the total molar concentration of Ni and Co is 2.0 mol / L), at the same time, under stirring conditions, the high-nickel solution that is continuously pumped into the low-nickel solution is fed at a rate of 100 mL / h , continuously pumped into 2 L 2 mol / L ammonia solution to form a reaction system, passed high-purity nitrogen gas to form an inert atmosphere, adjusted the temperature and kept it at 50 ° C, and at the same time adjusted the ammonia concentration of the reaction system...

Embodiment 2

[0070] This embodiment includes the following steps:

[0071] (1) Under stirring conditions, 3 L low-nickel solution (a mixed solution of nickel sulfate, cobalt sulfate, manganese sulfate and aluminum sulfate, wherein the molar ratio of Ni, Co, Mn, Al ions is 7:1:1.4:0.6 , the total molar concentration of Ni, Co, Mn, Al is 2.0 mol / L) with the feeding speed of 50mL / h, pump into 2 L high-nickel solution (the mixed solution of nickel sulfate and cobalt sulfate, wherein, Ni, Co ion The molar ratio is 9:1, and the total molar concentration of Ni and Co is 2.0 mol / L), at the same time, under stirring conditions, the high-nickel solution that will be continuously pumped into the low-nickel solution is fed at a rate of 100 mL / h, Continuously pump into 3 L 3 mol / L ammonia solution to form a reaction system, pass high-purity nitrogen gas as an inert atmosphere, adjust the temperature of the reaction system to maintain at 55 °C and continue stirring. At the same time, adjust the ammonia...

Embodiment 3

[0077] This embodiment includes the following steps:

[0078] (1) Under stirring conditions, 4 L of low-nickel solution (a mixed solution of nickel sulfate, cobalt sulfate, manganese sulfate and aluminum sulfate, wherein the molar ratio of Ni, Co, Mn, and Al ions is 7:1:1:1 , the total molar concentration of Ni, Co, Mn, Al is 2.0 mol / L) with the feeding speed of 50 mL / h, pump into 4 L high-nickel solution (the mixed solution of nickel sulfate and cobalt sulfate, wherein, Ni, Co ion The molar ratio of Ni and Co is 9:1, and the total molar concentration of Ni and Co is 2.0 mol / L). At the same time, the high-nickel solution that is continuously pumped into the low-nickel solution is continuously pumped into the 4 L, 4 mol / L ammonia solution to form a reaction system. At the same time, high-purity nitrogen gas was introduced as an inert atmosphere, and the temperature of the reaction system was increased by 60 ° C. At the same time, the ammonia concentration of the reaction system...

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Abstract

The invention provides a core-shell structure high nickel gradient nickel cobalt manganese aluminum quaternary positive electrode material and a preparation method thereof. The quaternary positive electrode material is spherical particles with an average particle size of 8-10 microns, the diameter of the inner core is 4-6 microns, the thickness of the shell layer is 2-3 microns and the surface ofthe shell layer is sheet-shaped. The nickel content gradually decreases from the center of the core to the surface of the shell structure, the manganese content gradually increases from the center ofthe core to the surface of the shell structure, the cobalt content is uniformly distributed and the aluminum content is uniformly or gradient distributed. The preparation method comprises the follow steps: a low nickel solution I is continuously added into a high nickel solution so that the nickel content in the high nickel solution is continuously reduced, and then the low nickel solution I is continuously pumped into an ammonia aqueous solution to form a continuous reaction system with reduced nickel content, and further hydroxide and carbonate are successively used as precipitants and ammonia water is used as a complexing agent to successively coprecipitate to generate a precursor with a core-shell structure; and then the precursor is sintered with lithium so as to prepare the core-shell structure high nickel gradient nickel cobalt manganese aluminum quaternary positive electrode material. The battery assembled by the positive electrode prepared by the core-shell structure high nickel gradient nickel cobalt manganese aluminum quaternary positive electrode material has high capacity, excellent cycle and rate performance and highly reversible charge-discharge reaction.

Description

technical field [0001] The invention relates to a lithium battery cathode material and a preparation method thereof, in particular to a gradient nickel-cobalt-manganese-aluminum quaternary cathode material with a core-shell structure and a preparation method thereof. Background technique [0002] Li[Ni 1−x−y co x mn y ]O 2 (NCM) has become the most promising cathode material due to its high reversible capacity, long cycle life, and high operating voltage. In order to further improve the capacity of existing NCMs, the nickel content is constantly increasing, but excessive nickel enrichment will lead to a decrease in the capacity retention and thermal stability of the material. In order to eliminate the negative impact of high nickel, NCM is doped with metal ions to improve structural stability. Among various doping metals, aluminum is the most widely used dopant because it plays a role in stabilizing the crystal structure in the host layered structure. In addition, sinc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/485H01M4/505H01M4/525H01M10/052
CPCH01M4/362H01M4/525H01M4/505H01M4/485H01M10/052H01M2004/028Y02E60/10
Inventor 童汇毛高强黄英德余荣天喻万景丁治英
Owner CENT SOUTH UNIV
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