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Positive electrode composite material and preparation method and application thereof

A technology for composite materials and positive electrode materials, which is applied in the field of positive electrode composite materials and their preparation, can solve the problems of difficult carbonization of organic carbon sources, affect material properties, and adversely affect the electrochemical properties of positive electrode materials, and achieve the effects of simple operation and reduced production costs.

Pending Publication Date: 2021-01-05
SVOLT ENERGY TECHNOLOGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The biggest defect of this technology is: because graphene has a large specific surface area and is easy to agglomerate, simple stirring and centrifugal heat treatment cannot make graphene evenly coat the surface of the positive electrode material
The defect of this technology is: the heat-treated high-purity nitrogen environment can well avoid the oxidation problem of graphene, but the positive electrode material that originally needs to be sintered in an oxygen environment will be sintered at a constant temperature of 750-800°C for 10-15h in a high-purity nitrogen environment. Seriously affect the performance of the material itself
[0007] CN105762345A discloses a method for heat treatment by spraying positive electrode material, graphene and organic carbon source dispersion liquid into a vertical calcination furnace filled with protective gas by using a sprayer. The disadvantage of this method is that a large amount of protection is required. gas, which increases the production cost, and it is necessary to add an organic carbon source other than graphene, which will reduce the specific capacity of the overall composite material. If the heat treatment time is too short, the organic carbon source is difficult to carbonize, and the coating on the surface of the positive electrode material will increase. The internal resistance of the material is not conducive to the electrochemical performance of the positive electrode material

Method used

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  • Positive electrode composite material and preparation method and application thereof
  • Positive electrode composite material and preparation method and application thereof
  • Positive electrode composite material and preparation method and application thereof

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Embodiment 1

[0059] This embodiment provides a positive electrode composite material, which includes a cobalt-free positive electrode material (LiNi 0.75 mn 0.25 o 2 , particle size is 4 μm) and graphene (sheet diameter is 2 μm, thickness is 1.5nm);

[0060] The present invention also provides a method for preparing the above positive electrode composite material, the preparation method comprising the following steps:

[0061] (1) Preparation of graphene slurry

[0062] PVP is mixed uniformly in NMP, add graphene (diameter is 2 μm, thickness 1.5nm), stir and mix, obtain the composite carbon slurry that PVP and graphene mass percentage are 0.5% and 0.35% respectively;

[0063] (2) Preparation of cathode composite materials

[0064] 4μm LiNi with a mass ratio of 1:0.02 to graphene 0.75 mn 0.25 o 2 Add to the obtained composite carbon slurry, stir at 1000rpm / min for 30min, the temperature at the air inlet is 199°C, and the wind speed is 31m 3 / h, the speed of the sample feeding perist...

Embodiment 2

[0066] This embodiment provides a positive electrode composite material, which includes a cobalt-free positive electrode material (LiNi 0.75 mn 0.25 o 2 , particle size is 3μm), graphene (sheet size is 1μm, thickness is 1nm) and CNT;

[0067] The present invention also provides a method for preparing the above positive electrode composite material, the preparation method comprising the following steps:

[0068] (1) Preparation of composite carbon slurry

[0069] Mix CMC and PVDF uniformly in NMP, add graphene (sheet diameter is 1 μm, thickness 1nm) and CNT, stir and mix to obtain CMC, PVDF and graphene mass percent respectively 0.2%, 0.1% and 0.2% composite carbon paste;

[0070] (2) Preparation of cathode composite materials

[0071] 4μm LiNi with graphene mass ratio of 0.98:0.01 0.75 mn 0.25 o 2 Add to the obtained composite carbon slurry, stir at 800rpm / min for 40min, the temperature at the air inlet is 180°C, and the wind speed is 25m 3 / h, the speed of the sample...

Embodiment 3

[0073] This embodiment provides a positive electrode composite material, which includes a cobalt-free positive electrode material (LiNi 0.75 mn 0.25 o 2 , particle size is 5μm), graphene (sheet size is 2μm, thickness is 0.5nm) and SP;

[0074] The present invention also provides a method for preparing the above positive electrode composite material, the preparation method comprising the following steps:

[0075] (1) Preparation of composite carbon slurry

[0076] Mix PPY uniformly in NMP, add graphene (sheet diameter is 2 μm, thickness 0.5nm) and SP, stir and mix, obtain PPY and graphene mass percentage are respectively 0.7% and 0.5% composite carbon slurry;

[0077] (2) Preparation of cathode composite materials

[0078] 4μm LiNi with graphene mass ratio of 1.02:0.04 0.75 mn 0.25 o 2 Add to the obtained composite carbon slurry, stir at 1200rpm / min for 20min, the temperature at the air inlet is 210°C, and the wind speed is 35m 3 / h, the speed of the sample feeding peri...

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Abstract

The present invention relates to a positive electrode composite material, the positive electrode composite material comprises a cobalt-free positive electrode material and a composite carbon coating layer formed on the surface of the cobalt-free positive electrode material, the particle size of the cobalt-free positive electrode material is 3-5 [mu]m, and the cobalt-free positive electrode material with the particle size within the range is more conducive to coating of composite carbon. Graphene is selected in the composite carbon, the ionic conductivity of the cobalt-free positive electrode material can be effectively improved, the positive electrode composite material can also effectively isolate an electrolyte, side reactions are reduced, and the first charge-discharge capacity of the material is improved.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a positive electrode composite material and a preparation method and application thereof. Background technique [0002] With the development of new energy vehicles, lithium-ion power batteries have attracted much attention as the most popular electric vehicle power batteries. Compared with the mature and stable commercial graphite anode, the research and development of cathode materials with high capacity, long life, low cost, safety and environmental protection is particularly urgent. The current commercial lithium battery cathode materials mainly include layered lithium cobaltate, ternary materials, spinel-structured lithium manganate, olivine-structured lithium iron phosphate, and cobalt-free cathode materials. The positive electrode material has the advantages of high specific capacity, energy density and power density, and low cost, but the electrochemical performance, ...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/505H01M4/525H01M4/62H01M10/0525
CPCH01M4/366H01M4/505H01M4/525H01M4/625H01M4/628H01M10/0525H01M2004/021H01M2004/028Y02E60/10
Inventor 王亚州郑军华马艳梅
Owner SVOLT ENERGY TECHNOLOGY CO LTD
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