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A method for stabilizing the crystal domain structure of lithium-rich layered oxide materials

A layered structure and oxide technology, applied in structural parts, electrochemical generators, electrical components, etc., can solve the problems of material grain structure stability, hidden dangers of crystal structure stability, and lower charging voltage platform. , to achieve excellent cycle life, broad market promotion effect, and small drop in discharge voltage platform

Active Publication Date: 2019-07-05
北京创能惠通科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The lithium-rich layered oxide material has a very high capacity. When the charge-discharge cut-off voltage is 2-4.8V, the reversible capacity can be greater than 250mAh / g, but the material has obvious problems such as a drop in the charge voltage plateau during the cycle. It means that there is a very large hidden danger in the crystal structure of the material during the process of deintercalating lithium ions, which seriously restricts the application of this material in actual batteries, which is a worldwide problem.
The decrease of the voltage platform has a lot to do with the crystal structure transformation of the material during the charging and discharging process. Some studies have reported that the structural stability of the material can be controlled by surface modification, but it can only solve the problem of structural stability on the grain surface of the material. It cannot solve the problem of structural stability inside the grain of the material, so it is necessary to improve the cycle stability of the material from the perspective of stabilizing the crystal structure inside the grain
In the patent (a "double crystal domain" lithium-rich layered oxide material and preparation method), we synthesized a lithium-rich layered oxide material with a "double crystal domain" crystal structure, although the material has relatively High electrochemical charge-discharge capacity and good cycle performance, but when the number of cycles increases, the voltage plateau of the discharge curve will still appear. Therefore, based on the original research, we have developed a stable lithium-rich layered oxide The crystal domain structure method and preparation technology of material materials can prevent the material from undergoing a large change in the crystal domain structure during the cycle, and further improve the cycle stability of the "double crystal domain" lithium-rich layered oxide

Method used

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  • A method for stabilizing the crystal domain structure of lithium-rich layered oxide materials
  • A method for stabilizing the crystal domain structure of lithium-rich layered oxide materials
  • A method for stabilizing the crystal domain structure of lithium-rich layered oxide materials

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Experimental program
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Effect test

Embodiment 1

[0049] The Al element stabilizes the crystal domain structure of the lithium-rich layered oxide material and its preparation technology, comprising the following steps:

[0050] e. First mix a certain proportion of metal acetates such as Mn, Ni, Co, Al and a proportion of lithium carbonate by ball milling.

[0051] f. Put the mixed powder above into a crucible, and heat up to 500°C at a rate of 5°C / min in a resistance furnace, keep it warm for 2 hours, and then cool with the furnace.

[0052] g. Put the material obtained in step b into a ball mill for 10 minutes, take it out, put it into a crucible and raise the temperature to 800°C at a rate of 5°C / min, keep it warm for 20 hours, and then cool it down to room temperature at a rate of 10°C / min.

[0053] h. Put the material obtained in step c into a sieving machine to sieve, and prepare the material component as Li[Li 0.16 mn 0.57 Ni 0.18 co 0.06 al 0.03 ]O 2 The Al element stabilizes the crystal domain structure material...

Embodiment 2

[0057] a. First mix a certain proportion of metal acetates such as Mn, Ni, Co, Mg and a proportion of lithium carbonate by ball milling.

[0058] b. Put the mixed powder above into a crucible, and heat up to 500°C at a rate of 5°C / min in a resistance furnace, keep it warm for 2 hours, and then cool down with the furnace.

[0059] c. Put the material obtained in step b into a ball mill for 10 minutes, take it out, put it into a crucible and raise the temperature to 800°C at a rate of 5°C / min, keep it warm for 20 hours, and then cool it down to room temperature at a rate of 10°C / min.

[0060] i. put the material obtained in step c into a sieving machine to sieve, and prepare the material component as Li [Li 0.16 mn 0.57 Ni 0.18 co 0.06 Mg 0.03 ]O 2 The Mg element stabilizes the crystal domain structure material of lithium-rich layered oxide material.

[0061] figure 1 (c) is the XRD pattern of the material, from which it can be clearly seen that there are two characterist...

Embodiment 3

[0064] a. First mix a certain proportion of Mn, Ni, Co metal acetate with TiO 2 The lithium carbonate and the proportioning lithium carbonate are evenly mixed by means of ball milling.

[0065]b. Put the mixed powder above into a crucible, and heat up to 500°C at a rate of 5°C / min in a resistance furnace, keep it warm for 2 hours, and then cool down with the furnace.

[0066] c. Put the material obtained in step b into a ball mill for 10 minutes, take it out, put it into a crucible and raise the temperature to 800°C at a rate of 5°C / min, keep it warm for 20 hours, and then cool it down to room temperature at a rate of 10°C / min.

[0067] j. Put the material obtained in step c into a sieving machine to sieve, and prepare the material component as Li [Li 0.16 mn 0.57 Ni 0.18 co 0.06 Ti 0.03 ]O 2 The Ti element stabilizes the crystal domain structure material of lithium-rich layered oxide material.

[0068] figure 1 (d) is the XRD pattern of the material, from which it can...

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Abstract

The invention discloses a method capable of improving stability of a crystal domain structure of a lithium-rich layered oxide material, and relates to the technical field of a positive electrode material of a lithium ion battery. One or more of the elements of Cr, Mg, Ti, Al and Ru are added for stabilizing the crystal domain structure of the lithium-rich layered oxide material; the general formula of the stabilized material is as follows: [Li<x / (2+x)>Mn<2x / (2+x)>M<2(1-x) / (2+x)>]O<2>, wherein M is Mn<1-y-z-w>Ni<y>Co<z>N<w>; N is selected from one or more of Cr, Mg, Ti, Al and Ru; x is greater than or equal to 0.1 and less than or equal to 0.8; y is greater than or equal to 0.1 and less than or equal to 0.5; z is greater than or equal to 0 and less than or equal to 0.25; and w is greater than 0 and less than or equal to 0.1. By adoption of the method capable of improving the stability of the crystal domain structure of the lithium-rich layered oxide material, the high discharge specific capacity of the material can be maintained and the high cycling performance can be realized; and compared with the positive electrode material of the lithium ion battery, the lithium-rich layered oxide material has the advantages of high capacity, long cycle life, and low cost.

Description

technical field [0001] The invention relates to the technical field of cathode materials for lithium-ion batteries, in particular to a method and preparation technology for stabilizing the structural crystal domains of lithium-rich layered oxide materials. A stable crystal domain structure in lithium-rich layered oxide materials. Background technique [0002] Energy crisis and environmental protection have become the urgent problems to be solved in the current sustainable development strategy of human society. Developed countries such as Japan, Germany, and the United States have vigorously invested in and developed projects such as solar energy, wind energy, and new energy vehicles that can alleviate the energy crisis and reduce environmental pollution. my country has also proposed a number of plans to support new energy and new energy vehicles from the state to the local level. As a chemical power source, lithium-ion batteries have the advantages of high specific energy,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/505H01M4/525H01M10/0525
CPCH01M4/505H01M4/525H01M10/0525Y02E60/10
Inventor 尉海军
Owner 北京创能惠通科技有限公司