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Rich-lithium positive electrode material of lithium ion battery having coreshell structure and preparation method of rich-lithium positive electrode material

A lithium-ion battery, core-shell structure technology, applied in the field of electrochemistry, can solve the problems of not comprehensively improving the electrochemical performance of materials, reducing the initial capacity of materials, poor high-rate discharge performance, etc., and achieving excellent charge-discharge cycle ability, wide Commercial use, the effect of improving rate performance

Inactive Publication Date: 2011-09-28
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, from the perspective of further commercial application, especially to meet the needs of high-performance power batteries, the ternary layered cathode material LiNi x co y mn 1-x-y o 2 There are still some problems, such as poor high rate discharge performance, low cycle specific capacity, fast capacity decay at high potential, low tap density, etc.
In order to improve the above phenomenon, many researchers have done a lot of work, mainly through doping and surface modification of ternary materials, but traditional doping or coating can only improve the performance of a certain aspect of the material, while Can not comprehensively improve the electrochemical performance of this type of material
For LiNi x co y mn 1-x-y o 2 Doping Al can improve the cycle stability of the material but reduce the initial capacity of the material; while Al 2 o 3 Coating, although the high-rate discharge performance has been improved to a certain extent, it cannot make the material have a higher cycle specific capacity (>200mAh / g). Therefore, it is necessary to find a preparation with high specific capacity, high rate performance, excellent cycle ability and The method of lithium-rich ternary layered cathode materials suitable for commercial production is of great significance

Method used

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  • Rich-lithium positive electrode material of lithium ion battery having coreshell structure and preparation method of rich-lithium positive electrode material
  • Rich-lithium positive electrode material of lithium ion battery having coreshell structure and preparation method of rich-lithium positive electrode material
  • Rich-lithium positive electrode material of lithium ion battery having coreshell structure and preparation method of rich-lithium positive electrode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] 1 First, weigh a certain amount of commercial spherical precursor [Ni 0.4 co 0.2 mn 0.4 ](OH) 2 with LiOH.H 2 O, mix and put into the agate mortar and grind for about 0.5h, mix well;

[0034]2 Then put the ground mixture in a tube furnace, and perform high-temperature calcination under air atmosphere, first at 450°C for 12 hours, then at 800°C for 8 hours, and naturally cool to room temperature to obtain the matrix material Li[Ni 0.4 co 0.2 mn 0.4 ]O 2 .

[0035] 3. Weigh a certain amount of citric acid, wherein citric acid: lithium acetate + manganese acetate (molar ratio) = 1:1, add deionized water to make a 100mL solution, the concentration is 0.2mol / L, and the 2 has been weighed The matrix material Li[Ni 0.4 co 0.2 mn 0.4 ]O 2 Add it into the solution, put it in a water bath at 80°C for stirring, and obtain solution A.

[0036] 4 According to the cladding layer Li 2 MnO 3 : Base material Li[Ni 0.4 co 0.2 mn 0.4 ]O 2 (Molar ratio)=1:9, weigh and fo...

Embodiment 2

[0042] 1-4 steps are the same as embodiment 1

[0043] 5 Put the gel in 4 into a vacuum oven at 100°C to dry for 24 hours, take it out, grind it, put it into a tube furnace, pretreat it at 500°C for 8 hours, and then heat it up to 900°C for two hours to obtain a core-shell gel Ternary materials of structure.

[0044] In Examples 1 and 2, ternary materials with a core-shell structure were synthesized at different temperatures. From figure 2 It can be seen that the coated ternary material particles still maintain a spherical shape, and their size is slightly larger than that before coating, and a layer of dense small particles is adsorbed on the surface of the particles. From image 3 The cross-sectional view of the sample particles after coating can also be seen that the material has an obvious coating layer, showing a core-shell configuration.

[0045] From Figure 4 It can be seen from the XRD pattern in the sample that after coating, the sample is still in the α-NaFeO2...

Embodiment 3

[0048] Steps 1-3 are the same as Example 1

[0049] 4 The surface of the base material is subjected to Li 2 MnO 3 of wrapping. According to the cladding layer Li 2 MnO 3 : matrix material (molar ratio)=1:12, weigh and form Li 2 MnO 3 Lithium acetate and manganese acetate are required, wherein lithium acetate: manganese acetate (molar ratio) = 2.05: 1, and lithium acetate and manganese acetate are added to deionized water to form 50 mL of solution B.

[0050] 5 Put the gel in 4 into a vacuum oven at 100°C to dry for 24 hours, take it out, grind it, put it into a tube furnace for pretreatment at 450°C for 5 hours, and then heat it up to 700°C for 10 hours to obtain a gel with a core-shell structure Ternary material.

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Abstract

The invention discloses a rich-lithium positive electrode material of a lithium ion battery having a coreshell structure and a preparation method of the rich-lithium positive electrode material, and belongs to the field of electrochemistry. The preparation method comprises the following steps of: calcining [NixCoyMn1-x-y](OH)2 and inorganic lithium salt in air to prepare [LiNixCoyMn1-x-y]O2, and adding the [LiNixCoyMn1-x-y]O2 into an organic acid solution to prepare a solution A; dissolving soluble manganate and soluble lithium salt into deionized water to prepare a solution B, adding the solution B into the solution A, keeping stirring to obtain gel C; and drying and pre-calcining the C, calcining the C at high temperature, taking a product out, grinding the product to obtain a ternary layered positive electrode material having the coreshell structure, wherein x is more than 0 and less than 0.5, and y is more than 0 and less than 0.5. Besides the characteristic of the ternary layered material, the material has perfect charging and discharging recycle capability under high capacitance and high potential of a rich-lithium compound; moreover, by surface cladding, the multiplying power performance of the material compared with the multiplying power performance of the non-cladded material is enhanced obviously.

Description

technical field [0001] The invention relates to a lithium-ion battery cathode material and a preparation method, in particular to a core-shell structure lithium-rich cathode material and a preparation method, belonging to the field of electrochemistry. Background technique [0002] Lithium-ion batteries have become one of the hot spots in the field of high-energy battery research in recent years because of their significant advantages such as high energy, high voltage, long life, no memory effect, good safety performance, no pollution, good cost performance, and high energy density. LiCoO 2 It is the earliest positive electrode material used in commercial lithium-ion batteries, but its high cost and unsafe factors of overcharging greatly limit the further application of lithium-ion batteries. Therefore, looking for more than LiCoO 2 Cathode materials with better comprehensive performance are currently a research hotspot in the field of lithium-ion batteries. [0003] LiNi...

Claims

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Application Information

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IPC IPC(8): H01M4/505H01M4/525H01M4/131H01M4/1391
CPCY02E60/12Y02E60/122Y02E60/10
Inventor 赵煜娟孙召琴冯海兰孙少瑞
Owner BEIJING UNIV OF TECH
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