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A lithium-rich manganese-based positive electrode material and preparation method thereof

A lithium-rich manganese-based, positive electrode material technology, applied in the direction of battery electrodes, structural parts, electrical components, etc., can solve the surface structure damage of lithium-rich manganese-based positive electrode materials, the inability to meet the performance requirements of electrode materials, and the reduction in structural stability, etc. problem, to achieve the effect of reducing the first irreversible capacity loss, improving the diffusion of lithium ions, and improving the bonding strength

Active Publication Date: 2020-04-21
CHINA AUTOMOTIVE BATTERY RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are still some problems with this system material as a candidate material for high-energy lithium-ion batteries: first, the lithium ion diffusion coefficient of the system material (10 -15 ~ 10 -12 cm 2 the s -1 ) and electronic conductivity (10 -7 ~ 10 -8 S cm -1 ) is much lower than the traditional layered cathode material, which leads to a significant decrease in the capacity of the material at a higher rate such as ≥1C and the deterioration of the cycle performance, which cannot meet the performance requirements of the electrode material for the practical application of lithium-ion batteries
However, in the above two articles, the liquid-phase method was used to prepare the surface-modified materials. The surface structure of the lithium-rich manganese-based positive electrode material is easily damaged, resulting in a decrease in structural stability, and its low heat treatment stability makes it difficult for vanadium ions to enter the core layer. Diffusion properties play a role in stabilizing the bulk structure of the material

Method used

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  • A lithium-rich manganese-based positive electrode material and preparation method thereof
  • A lithium-rich manganese-based positive electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] In the lithium-rich manganese group with an average particle size of 10μm (molecular formula: Li 1.2 Mn 0.56 Ni 0.16 Co 0.08 O 2 ) 5.0% (mass fraction) of LiV is formed on the surface of the core 3 O 8 (1 / 2Li 2 O·3 / 2V 2 O 5 ) Surface modification layer.

[0036] The preparation method is as follows:

[0037] Weigh 100.0g of lithium-rich manganese-based core material (Li 1.2 Mn 0.56 Ni 0.16 Co 0.08 O 2 ), 6.098g ammonium vanadate (NH 4 VO 3 ) And 0.640g lithium carbonate (Li 2 CO 3 ) Use mechanical ball milling to mix evenly, and then treat in air at 500℃ for 4h to get LiV 3 O 8 Surface modified lithium-rich manganese-based cathode material, the total alkali content of the tested modified material is 2578ppm.

[0038] The electrochemical performance test is as follows:

[0039] Mix the target product with the conductive agent acetylene black and the binder PVDF (polyvinylidene fluoride) at a mass ratio of 8:1:1, and then mix them with NMP (N-methyl-pyrrolidone) to form a slurry w...

Embodiment 2

[0042] In the lithium-rich manganese group with an average particle size of 5μm (molecular formula: Li 1.2 Mn 0.56 Ni 0.13 Co 0.13 O 2 ) 3.0% (mass fraction) of Li is formed on the surface of the inner core 3 VO 4 (3 / 2Li 2 O ▪1 / 2V 2 O 5 ) Surface modification layer.

[0043] The preparation method is as follows:

[0044] Weigh 100.0g of lithium-rich manganese-based cathode material (Li 1.2 Mn 0.56 Ni 0.13 Co 0.13 O 2 ), 2.012g vanadium pentoxide V 2 O 5 And 2.784g of lithium hydroxide (LiOH) are mixed uniformly with a mechanical fusion machine, and then treated at 800°C in the air for 10 hours to obtain Li 3 VO 4 Surface modified lithium-rich manganese-based cathode material, the total alkali content of the tested modified material is 2808ppm.

[0045] The electrochemical performance test is the same as in Example 1;

[0046] Electrochemical tests show that the first discharge specific capacity is 310.8 and 285.2mAh / g in the voltage range of 0.1C and 2.0-4.8V, and the first charge-disc...

Embodiment 3

[0048] In the lithium-rich manganese base material with an average particle size of 15μm (molecular formula: Li 1.167 Mn 0.533 Ni 0.2 Co 0.1 O 2 ) 15.0% (mass fraction) of LiVO is formed on the inner core surface 3 (1 / 2Li 2 O˙1 / 2V 2 O 5 ) Surface modification layer.

[0049] The preparation method is as follows:

[0050] Weigh 100.0g of lithium-rich manganese-based cathode material (Li 1.167 Mn 0.533 Ni 0.2 Co 0.1 O 2 ), 11.754g vanadium dioxide VO 2 And 5.94g of lithium hydroxide (LiOH) are mixed uniformly by atomic layer deposition technology, and then treated in the air at 900°C for 1.0h to obtain LiVO 3 Surface modified lithium-rich manganese-based cathode material, the total alkali content of the tested modified material is 1280 ppm.

[0051] The electrochemical performance test is the same as in Example 1;

[0052] Electrochemical tests show that the first discharge specific capacity is 298.6 and 292.2mAh / g in the voltage range of 0.1C and 2.0-4.8V, and the first charge-discharge...

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Abstract

The invention provides a lithium-rich manganese-based positive electrode material and a preparation method thereof. The lithium-rich manganese-based positive electrode material comprises a lithium-rich manganese-based core and a surface modification layer, wherein the lithium-rich manganese-based core comprises a chemical component with a general formula Li<1+x>Mn<y>M<z>O<r>, wherein M is at least one of Ni, Co, Al, Mg, Ti, Fe, Cu, Cr, Mo, Zr, Ru, Sn or V, x is smaller than or equal to 1 and greater than 0, y is smaller than or equal to 1 and greater than 0, z is smaller than 1 and greater than or equal to 0 and r smaller than or equal to 3 and greater than or equal to 1.8; the surface modification layer comprises a vanadium-doped gradient layer and a coating layer of a lithium vanadium oxide. The positive electrode material has a low initial charge-discharge irreversible capacity loss and excellent cycle performance and rate capability. According to the method, the bonding strength between the lithium vanadium oxide of the surface modification layer and the core of the lithium-rich manganese-based positive electrode material can be improved, the total alkali content of the material is reduced through reaction of the vanadium oxide and the residual lithium on the surface of the lithium-rich manganese-based positive electrode material is reduced and the problem of high-pressure cycle expansion of a battery is solved.

Description

Technical field [0001] The invention relates to the technical field of preparation of lithium ion battery cathode materials, in particular to a lithium-rich manganese-based anode material and a preparation method thereof. Background technique [0002] As a new type of high-energy green battery, lithium-ion batteries are widely used in portable electronic products such as notebook computers and mobile phones, and are expanded to large and medium-sized energy storage equipment and new energy electric vehicles. This has a great impact on the energy density of lithium-ion batteries. , Cycle life, cost and safety put forward higher requirements. Cathode materials are an important part of lithium-ion batteries, accounting for about 30%-40% of the total battery cost. Therefore, improving the performance of the cathode material and reducing its cost are extremely critical for the development of lithium-ion batteries. [0003] In recent years, the lithium-rich manganese-based cathode mate...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/485H01M4/505H01M4/525H01M4/62H01M10/0525
CPCH01M4/366H01M4/485H01M4/505H01M4/525H01M4/62H01M10/0525Y02E60/10
Inventor 高敏王忠任志敏王振尧尹艳萍卢世刚庄卫东
Owner CHINA AUTOMOTIVE BATTERY RES INST CO LTD