Modification method of lithium-rich cathode material

A technology of lithium-rich positive electrode materials and positive electrode materials, applied in battery electrodes, electrical components, circuits, etc., can solve the problems of reducing the discharge capacity of materials, achieve low cost, increase rate capacity, and reduce the effect of irreversible capacity loss for the first time

Inactive Publication Date: 2013-03-13
IRICO
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Coating a thin coating layer on the surface of the electrode material can not only reduce the first irreversible loss of the lithium-rich material, but also improve the rate capacity of the material. At present, Al, Al 2 o 3 , Al(OH) 3 , AlPO 4 , RuO 2 , MnO 2 、TiO 2 such as single-layer surface modification and double-layer Al 2 o 3 -RuO 2 、Al 2 o 3 -AlPO 4 Surface modification has successfully improved the electrochemical performance of lithium-rich materials, but since these materials are electrochemically inert, it may reduce the discharge capacity of the material

Method used

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  • Modification method of lithium-rich cathode material

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Experimental program
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Effect test

Embodiment 1

[0021] 1. According to the molecular formula Li[Ni 0.2 Li 0.2 mn 0.6 ]O 2 The ratio of Li, Ni, Mn to prepare LiAc, Ni(Ac) 2 and Mn(Ac) 2 Mixed solution, the total metal (Li+Ni+Mn) ion concentration is 1mol / L;

[0022] 2. Configure the citric acid solution according to the ratio of citric acid: total metal ions = 1:1 (molar ratio). Under stirring conditions, add the mixed solution of metal salts to the citric acid solution dropwise, stir and evaporate in a water bath at 80°C, and finally A yellow-green gel was obtained, and after drying in a vacuum oven at 150°C for 12 hours, a dry and slightly fluffy bulk precursor was obtained; since the aforementioned citric acid solution was prepared by adding deionized water, in the subsequent evaporation process The deionized water is completely removed, so the deionized water has no other effects except for dissolving citric acid, so the added deionized water can completely dissolve the citric acid or a little more. The amount of de...

Embodiment 2

[0029] 1-3 steps are the same as embodiment 1;

[0030] 4. Disperse 0.99 g of the lithium-rich cathode material prepared above in 100 ml of FeC with a concentration of 0.095 g / L 2 o 4 Sonicate the solution for 1 hour, then vigorously stir for 2 hours, and drop 50ml of NH with a concentration of 0.076g / L into it 4 h 2 PO 4 solution, stirred for 1 h to make it evenly mixed, and the resulting slurry was completely dried at 85°C.

[0031] 5. Then sinter at 400°C for 6 hours to obtain surface-modified Li[Ni 0.2 Li 0.2 mn 0.6 ]O 2 .

[0032] X-ray diffraction (XRD) analysis showed that the main phase of the product was Li[Ni 0.2 Li 0.2 mn 0.6 ]O 2 ( figure 1 The map corresponding to 1wt.% in ), the structure has not been destroyed after coating.

[0033] Electrochemical tests show that when charging and discharging at 1C and 2C, the initial discharge capacity is 150mAh / g (see image 3 ) and 138mAh / g (see Figure 4 ), after 50 cycles, it still maintains a high capacit...

Embodiment 3

[0035] 1-3 steps are the same as embodiment 1;

[0036] 4. Disperse 0.95 g of the obtained lithium-rich cathode material in 100 ml of FeC with a concentration of 0.47 g / L 2 o 4 Sonicate the solution for 1h, then stir vigorously for 2h, and drop 50ml of NH with a concentration of 0.38g / L into it 4 h 2 PO 4 solution, stirred for 1 h to make it evenly mixed, and the resulting slurry was completely dried at 85°C.

[0037] 5. Then sinter at 400°C for 6 hours to obtain surface-modified Li[Ni 0.2 Li 0.2 mn 0.6 ]O 2 .

[0038] X-ray diffraction (XRD) analysis showed that the main phase of the product was Li[Ni 0.2 Li 0.2 mn 0.6 ]O 2 ( figure 1 The map corresponding to 5wt.% in the middle), and its structure has not been destroyed after coating.

[0039] Electrochemical tests show that when charging and discharging at 1C and 2C, the first discharge capacity is 200mAh / g (see image 3 ) and 180mAh / g (see Figure 4 ), after 50 cycles, it still maintains a high capacity, in...

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Abstract

The invention relates to a surface modification method of lithium ion battery cathode material, and especially a modification method of a lithium-rich cathode material. The method is characterized by comprising the following steps: preparing a lithium ion battery cathode material Li [NixLi1/3-2x / 3Mn2/3-x/3] O2, wherein x satisfies the relation of 1/5<= x<=1/3; dispersing the lithium-rich cathode material in a FeC2O4 solution with concentration no higher than 0.95g / L in and treating the solution with ultrasound for 0.5-5 h, then stirring for 0.5-5 h, dropwise adding NH4H2PO4 solution with concentration no higher than 0.76g / L, and completely drying the obtained slurry at 80-150 DEG C; and sintering at 200-700 DEG C for 4-15 h to obtain FePO4 surface modified lithium ion battery cathode material. The invention has advantages of simple process, low temperature heat treatment, simple operation and low cost, and is suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to a method for modifying the surface of a positive electrode material of a lithium ion battery, in particular to a method for modifying a lithium-rich positive electrode material. Background technique [0002] In recent years, under the environment of soaring gasoline prices and global advocacy of new energy, energy saving and emission reduction, and low-carbon economy, lithium-ion batteries with high energy density and high power density have become the focus of attention. Inexpensive and abundant iron-based and manganese-based cathode materials become the most promising candidates, LiFePO 4 and LiMn 2 o 4 As a cathode material, it has been widely used, but due to the limitation of the theoretical capacity of these two materials, the energy density is low. Layered lithium-rich manganese-based cathode material xLi 2 MnO 3 ·(1-x)LiMO 2 (M=Co,Ni 1 / 2 mn 1 / 2 …) have attracted extensive attention due to their high voltage and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/505H01M4/525H01M4/58H01M4/1391
CPCY02E60/122Y02E60/10
Inventor 郭彩霞
Owner IRICO
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