Method for modifying high-rate lithium-rich anode material

A technology of lithium-rich cathode materials and cathode materials, which is applied in electrode manufacturing, battery electrodes, electrical components, etc., can solve problems such as difficult industrialized large-scale production, obstacles to large-scale applications, and poor rate performance.

Inactive Publication Date: 2009-10-21
BEIJING UNIV OF TECH
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Problems solved by technology

However, the poor rate performance seriously hinders its large-scale application.
Although, J.Cho et al. synthesized Li with high rate performance by hydrothermal method 0.88 [Li 0.18 co 0.33 mn 0.49 ]O 2 and Li 0.93 [Li 0.21 co 0.28 mn 0.51 ]O 2 Nanowires and nanosheets, but very harsh experimental conditions make it difficult to carry out large-scale industrial production

Method used

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  • Method for modifying high-rate lithium-rich anode material
  • Method for modifying high-rate lithium-rich anode material
  • Method for modifying high-rate lithium-rich anode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 1. First, according to the molecular formula Li[Ni 0.2 Li 0.2 mn 0.6 ]O 2 The ratio of Ni and Mn in the preparation of NiSO 4 and MnSO 4 Mixed solution, the cation concentration is 2mol / L;

[0023] 2. Use a peristaltic pump to drop the mixed solution and LiOH solution into the reaction kettle, and control the pH value at about 11, and heat it in a water bath to 60°C. After the reaction is completed, filter, wash, and dry in a vacuum oven at 120°C for 12 hours to obtain the precursor M(OH) 2 (M=Mn, Ni):

[0024] 3. Combine the precursor with LiOH·H 2 O according to the molecular formula Li[Ni 0.2 Li 0.2 mn 0.6 ]O 2 After mixing evenly, keep the temperature at 450°C for 6h in the air atmosphere, continue to heat up to 950°C for 10h, and cool to room temperature with the furnace to obtain the lithium-ion battery cathode material Li[Ni 0.2 Li 0.2 mn 0.6 ]O 2 ;

[0025] 4. Disperse the lithium-rich cathode material obtained above in 0.194g / L MnSO 4 The solut...

Embodiment 2

[0030] 1-3 steps are the same as embodiment 1;

[0031] 4. Disperse the obtained lithium-rich cathode material in 0.777g / L MnSO 4 The solution was sonicated for 1h, and vigorously stirred for 2h, then 0.487g / L Na 2 CO 3 The solution was dripped into the strongly stirred MnSO4 through a peristaltic pump 4 solution, after dripping, filter the solution and dry it at 120°C;

[0032] 5. Then sinter at 300°C for 6 hours to obtain surface-modified Li[Ni 0.2 Li 0.2 mn 0.6 ]O 2 .

[0033] 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 (See figure 1 ), its structure was not damaged after coating.

[0034] Electrochemical tests show that the first discharge capacity is 192mAh / g at 0.5C (see figure 2 ), the capacity of 190mAh / g is still maintained after 50 cycles, and the capacity retention rate is as high as 98.9%. attenuation.

Embodiment 3

[0036] 1-3 steps are the same as embodiment 1;

[0037] 4. Disperse the obtained lithium-rich cathode material in 0.777g / L MnSO 4 The solution was sonicated for 1h, and vigorously stirred for 2h, then 0.487g / L Na 2 CO 3 The solution was dripped into the strongly stirred MnSO4 through a peristaltic pump 4 solution, after dripping, filter the solution and dry it at 120°C;

[0038] 5. Then sinter at 500°C for 6h to obtain surface-modified Li[Ni 0.2 Li 0.2 mn 0.6 ]O 2 .

[0039] 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 (See figure 1 ), its structure was not damaged after coating. However, MnCO 3 The product decomposed at 500°C is not MnO 2 , but Mn 5 o 8 .

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Abstract

The invention belongs to the fields of lithium ion battery anode materials and electrochemistry. A lithium-rich material with high capacity and stable cycle performance cannot meet the requirement of quick charge and discharge of a high-power lithium ion battery. A surface modified lithium-rich material comprises a coating layer MnO2 and a main phase Li[NixLi1 / 3-2x / 3Mn2 / 3-x / 3]O2(x is more than or equal to 1 / 5 and less than or equal to 1 / 3), and the mass ratio of the coating layer and the main phase is 0 to 6 percent. A preparation method comprises that: the obtained lithium-rich anode material Li[Ni0.2Li0.2Mn0.6]O2 is dispersed in 0.194-1.17 g / L MnSO4 solution, subjected to ultrasound for 1 hour, and violently stirred for 2 hours; and 0.122-0.731 g / L Na2CO3 solution is added into the violently stirred MnSO4 solution dropwise by a peristaltic pump, and the mixed solution is filtered after the dropwise addition, dried at 120 DEG C and sintered at a temperature of between 300 and 500 DEG C for 4 to 8 hours to obtain the surface modified Li[NixLi1 / 3-2x / 3Mn2 / 3-x / 3]O2(x is more than or equal to 1 / 5 and less than or equal to 1 / 3). The preparation method reduces initial irreversible capacity loss of the lithium-rich material, greatly improves the cycle performance under high rate, and can meet the requirement of the high-power lithium ion battery.

Description

technical field [0001] The invention relates to a surface modification method of a lithium-rich cathode material with high rate performance, and belongs to the field of cathode materials and electrochemistry of lithium ion batteries. Background technique [0002] The current commercial cathode material LiCoO 2 The capacity is relatively low, and the marketization of 3G electronic products and electric vehicles that have high requirements for battery capacity has brought certain difficulties. In recent years, lithium-rich cathode materials with higher voltage and higher capacity have attracted widespread attention. [0003] Lithium-rich cathode materials are mainly layered materials Li 2 MnO 3 with LiMO 2 (M=Ni, Co, Fe, Cr) formed solid solution xLi 2 MnO 3 ·(1-x)LiMO 2 , can also be written as Li[M x Li 1 / 3-2x / 3 mn 2 / 3-x / 3 ]O 2 . Li[Li 1 / 3 mn 2 / 3 ]O 2 with and LiCoO 2 Similar to the ideal layered structure, the number ratio of Li and Mn in the M layer is 1:2, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/58
CPCY02E60/12Y02E60/10
Inventor 赵煜娟赵春松孙少瑞王绥军夏定国
Owner BEIJING UNIV OF TECH
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