Lithium ion battery gradient core shell cathode material and synthetic method thereof

A technology for lithium-ion batteries and positive electrode materials, applied in battery electrodes, chemical instruments and methods, circuits, etc., can solve problems such as unstable structures, low material capacity, safety performance concerns, etc., and achieve the goal of improving cycle performance and material capacity Effect

Active Publication Date: 2013-08-07
HARBIN INST OF TECH
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Controlling the ratio of Ni, Co, and Mn elements is one of the key factors to optimize the performance of ternary cathode materials. If the Ni content is too high, the safety performance of the battery will be reduced, and if the Co content is too high, the material cost will be increased. Lead to problems such as low material capacity and structural instability
At present, the ratios of the three elements Ni, Co, and Mn in the synthetic materials are 1:1:1, 4:2:4, 5:2:3, 6:2:2, and 8:1:1. Coating modification is carried out, but a better modification method has not been found to balance the synergistic effect of the three elements, which seriously affects the performance of the material and the commercialization of the product
[0003] Take LiNi 0.5 co 0.2 mn 0.3 o 2 The safety performance of the power lithium-ion battery as the cathode material is worrying, and its low-temperature performance cannot meet the needs of consumers.

Method used

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Effect test

specific Embodiment approach 1

[0017] Specific implementation mode one: In this embodiment, during the synthesis process, the precursor Ni x co y mn z (OH) 2 It is a nuclear structure with a particle size of 5-10 microns; binary lithium nickel manganese oxide precursor Ni x mn y (OH) 2 For the second layer, the thickness of the layer is 2-5 microns; the precursor of monobasic lithium manganate MnCO 3 It is the outermost layer with a thickness of 2-5 microns, and it can also be the precursor of lithium cobalt oxide Co 3 o 4 or CoCO 3 , the layer thickness is 2-10 microns, the synthesis method is as follows:

[0018] 1. Weigh the nickel source compound, cobalt source compound and manganese source compound respectively according to the molar ratio of 1:1:1, 5:2:3, 6:2:2, 8:1:1 or 4:2:4, And dissolve in deionized water and mix evenly, add precipitant sodium hydroxide or sodium carbonate and a certain amount of complexing agent ammonia water dropwise, control the molar ratio of metal salt to ammonia wat...

specific Embodiment approach 2

[0022] Specific implementation mode 2: In this implementation mode, taking the ternary 5:2:3, the outermost layer is lithium manganate as an example, coprecipitation is used to prepare gradient core-shell positive electrode materials for lithium-ion batteries:

[0023] 1. Weigh nickel sulfate, cobalt sulfate, and manganese sulfate respectively in a molar ratio of 5:2:3, and dissolve them in deionized water and mix them evenly. Add 2mol / L precipitating agent sodium hydroxide and a certain amount of complexing agent ammonia water one by one. Add it dropwise, control the molar ratio of metal salt and ammonia water to 1:0.75, the pH value of the reaction is between 10-11, react at 60°C for 12h, and stir continuously at a speed of 600 rpm to synthesize the precursor of the ternary cathode material (Ni 0.5 co 0.2 mn 0.3 )(OH) 2 .

[0024] In this embodiment, the ternary precursor can be commercially purchased and ready-made.

[0025] 2. Use the ternary precursor synthesized in ...

specific Embodiment approach 3

[0033] Specific embodiment three: the difference between this embodiment and specific embodiment two is that LiNi 0.5 co 0.2 mn 0.3 o 2 As the core material, then coated with spinel LiMn 2 o 4 , and finally coated with spinel LiNi 0.5 mn 1.5 o 4 .

[0034] Mn dissolves in the electrolyte, and trivalent Mn can induce the Jahn-Teller effect, and the outermost layer of lithium nickel manganese oxide can effectively prevent this effect.

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Abstract

The invention provides a lithium ion battery gradient core shell cathode material and synthetic method thereof, and relates to a lithium ion battery cathode material and synthetic method thereof. The lithium ion battery gradient core shell cathode material provided by the present invention may have two kinds of core shell structures as follows: a two-layer structure: a ternary material is used as a core material, and a binary material or a unitary material is casing material, and the ternary material external layer is covered by the binary material or the unitary material; three-layer structure: the ternary material is used as a core material, and the binary material and the unitary material are casing materials, and the ternary material external layer is covered with the binary material, and the binary material is covered with the unitary material. The synthetic method includes: employing a coprecipitation method for obtaining a precursor, and then adding lithium source, calcining and coating to obtain the ternary gradient core shell material. Under the prerequisite that the structure stability of the material is kept, the cost is reduced, and the gram capacity of the material is improved, and the material circulating performance and rate capability of the material are improved, and the safety performance and low temperature performance of the ternary cathode material are increased, and the preparation technology is optimized and improved.

Description

technical field [0001] The invention relates to a lithium ion battery cathode material and a synthesis method thereof, in particular to a lithium ion battery gradient core-shell structure cathode material and a synthesis method thereof. Background technique [0002] Lithium-ion battery ternary material LiNi 1-x-y co x mn y o 2 Due to the advantages of high gram capacity, good safety, low cost, matching working voltage with the existing electrolyte, and no environmental pollution, it is considered to be a positive electrode material that can replace lithium cobalt oxide and has development potential. Due to the synergistic effect, the performance of the ternary material is better than that of any single unit material. Controlling the ratio of Ni, Co, and Mn elements is one of the key factors to optimize the performance of ternary cathode materials. If the Ni content is too high, the safety performance of the battery will be reduced, and if the Co content is too high, the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/505H01M4/525H01M4/62H01M4/1391C01G45/00C01G53/00
CPCY02E60/122Y02E60/10
Inventor 王振波张音薛原金彦章
Owner HARBIN INST OF TECH
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