Preparation method of lithium phosphate coated lithium-ion battery ternary positive electrode material

A technology for lithium-ion batteries and positive electrode materials, which is applied in the direction of battery electrodes, positive electrodes, electrical components, etc., can solve the problems of easily bringing water into the battery, poor material cycle performance, and poor material storage performance, so as to avoid water and Carbon dioxide exposure, small effect on specific capacity, and low production cost

Inactive Publication Date: 2019-08-30
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, ternary materials still have many disadvantages, such as Ni 4+ It is easy to react with the electrolyte, which leads to poor cycle performance of the material, and the presence of lithium-nickel mixed row during the sintering process of the material forms a large amount of lithium residue (lithium oxide, lithium hydroxide) on the surface, which makes the material absorb a large amount of water and carbon dioxide in the air, resulting in material storage The performance is poor, and it is easy to bring water into the battery during the battery processing process, which will deteriorate the battery performance and cause safety problems such as flatulence

Method used

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  • Preparation method of lithium phosphate coated lithium-ion battery ternary positive electrode material
  • Preparation method of lithium phosphate coated lithium-ion battery ternary positive electrode material
  • Preparation method of lithium phosphate coated lithium-ion battery ternary positive electrode material

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Dissolving polyphosphoric acid in 60g dimethyl sulfoxide is configured into a polyphosphoric acid solution with a mass fraction of 0.4%, adding 10g LiNi 0.8 co 0.1 mn 0.1 o 2 Stir the material for 30 minutes to disperse it evenly, and evaporate dimethyl sulfoxide to dryness at 140° C. to obtain a lithium phosphate-coated ternary cathode material. For its physical and chemical properties, see figure 1 , figure 2 , image 3 . XRD shows that the obtained product has high crystallinity, and LiNi after lithium phosphate coating 0.8 co 0.1 mn 0.1 o 2 The structure of the material does not change. Due to the small amount of lithium phosphate coating, the peak of lithium phosphate is not detected. The SEM image shows that LiNi before and after coating 0.8 co 0.1 mn 0.1 o 2 The morphology of the material does not change significantly. It can be seen from the EDS scanning image of the phosphorus element that the phosphorus element is uniformly dispersed in LiNi 0.8...

Embodiment 2

[0033] Dissolve a certain amount of pyrophosphoric acid in 10g N,N-dimethylformamide to form a polyphosphoric acid solution with a mass fraction of 0.8%, add 10g LiNi 0.6 co 0.2 mn 0.2 o 2 Stir the material for 30 minutes to disperse evenly, and evaporate N,N-dimethylformamide to dryness at 140°C to obtain lithium phosphate-coated LiNi 0.6 co 0.2 mn 0.2 o 2 Material. Its XRD characterization shows that the obtained product has high crystallinity, and LiNi after lithium phosphate coating 0.6 co 0.2 mn 0.2 o 2 Material structure does not change, can refer to in embodiment 1 figure 1 , SEM images show LiNi before and after lithium phosphate coating 0.6 co 0.2 mn 0.2 o 2 The material morphology does not change significantly, with reference to the figure 2 . The resulting product was assembled into a button battery to test its charge and discharge capacity and rate performance at 25°C. Charge and discharge were performed at different rates. LiNi before and after li...

Embodiment 3

[0035] Dissolve a certain amount of polyphosphoric acid in 100g dimethyl sulfoxide to prepare polyphosphoric acid solutions with mass fractions of 0.05%, 0.2%, and 0.8%, respectively, and add 10g LiNi 0.8 co 0.1 mn 0.1 o 2 Stir the material for 30 minutes to disperse evenly, and evaporate dimethyl sulfoxide to dryness at 140°C to obtain lithium phosphate-coated LiNi 0.8 co 0.1 mn 0.1 o 2 Material. Take the above materials and uncoated LiNi respectively 0.8 co 0.1 mn 0.1 o 2 The material was mixed with deionized water at a liquid-solid ratio of 10:1, sealed, stirred for 2 minutes and then left to stand for 30 minutes to test the pH of the solution. The results are shown in Table 1. It can be seen from the pH that after adding the polyphosphoric acid solution, the lithium residue (lithium oxide, lithium hydroxide) on the surface of the material is converted into lithium phosphate, and the lithium residue on the surface of the ternary positive electrode material can be ...

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Abstract

The invention discloses a preparation method of a lithium phosphate coated lithium-ion battery ternary positive electrode material. The method comprises the steps of (1) dissolving a phosphoric acid source in an organic solvent to form a solution, wherein the mass fraction of the phosphoric acid source in the solution is 0.05-0.8%; and (2) adding a lithium ion battery ternary positive electrode material into the solution obtained in the step (1), stirring for 5-120 minutes for uniform dispersion, and drying until the organic solvent completely evaporates to obtain the lithium phosphate coatedlithium-ion battery ternary positive electrode material. Lithium residues (lithium oxide, lithium hydroxide) on the surface of the ternary positive electrode material can be removed by using the phosphoric acid, and the surface is coated with lithium phosphate with uniform distribution and compact structure at the same time, thereby effectively slowing down the phenomenon of water absorption and oxygen absorption of the ternary positive electrode material in the air, improving the stability of the material in an electrolyte, and enabling the storage performance and cycle performance of the material to be significantly improved. The method disclosed by the invention has the advantages of simplicity, low cost and great industrialization potential.

Description

technical field [0001] The invention relates to a preparation method of a lithium ion battery material, belongs to the technical field of lithium ion material preparation, and in particular relates to a preparation method of a lithium phosphate-coated lithium ion battery ternary cathode material. Background technique [0002] Nowadays, problems such as environmental pollution and energy crisis caused by resource shortage are becoming more and more obvious. The development of high-efficiency, clean, renewable energy and related technologies is becoming more and more important. As a new type of energy storage device, lithium-ion batteries have high energy density, high working voltage, The advantages of long cycle life and good safety performance are of great significance for solving energy shortages and reducing environmental pollution. Among them, the positive electrode material is the key factor affecting the electrochemical performance, safety performance and price cost of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/505H01M4/525H01M4/62H01M10/0525
CPCH01M4/366H01M4/505H01M4/525H01M4/624H01M4/628H01M10/0525H01M2004/028Y02E60/10
Inventor 熊训辉林志华范梦娜马向东罗煜翔杨成浩
Owner SOUTH CHINA UNIV OF TECH
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