Method for non-destructively evaluating molar ratio of lithium to cobalt in lithium battery electrode

A lithium-cobalt molar ratio, non-destructive evaluation technology, applied in the field of electrochemical measurement, can solve the problems of cumbersome and inaccurate lithium-cobalt molar ratio measurement, and achieve the effects of less human interference, lower pollution emissions, and lower relative errors

Pending Publication Date: 2021-12-03
XTC NEW ENERGY MATERIALS(XIAMEN) LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a method for non-destructive evaluation of the lithium-cobalt molar ratio in lithium battery electrodes in order to overcome the cumbersome and inaccurate determination of the lithium-cobalt molar ratio of the existing lithium cobalt oxide material

Method used

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  • Method for non-destructively evaluating molar ratio of lithium to cobalt in lithium battery electrode
  • Method for non-destructively evaluating molar ratio of lithium to cobalt in lithium battery electrode
  • Method for non-destructively evaluating molar ratio of lithium to cobalt in lithium battery electrode

Examples

Experimental program
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Effect test

Embodiment 1

[0049] Select a commercially available lithium cobaltate material of a known lithium-cobalt mol ratio as the reference sample marked as M 0 , and at the same time choose the same type of commercially available lithium cobalt oxide material as the sample to be tested, marked as M 1. The above reference sample and the sample to be tested were respectively mixed with the conductive agent Super P and the binder PVDF according to the same mass ratio of 9:0.14:0.2 and the same process conditions to make electrode test sheets and assemble them into button cells. Among them, the buckle specification is CR2023, the positive electrode is lithium cobalt oxide material, the negative electrode is lithium sheet, the diaphragm is polypropylene film, the electrolyte solvent is a mixture of EC / DEC with a volume ratio of 1:1, and the conductive salt is 1M Lithium hexafluorophosphate. The packaging pressure of the buckle is 800Pa, and the packaging time is 5 seconds. The test batteries made o...

Embodiment 2

[0056] Continue to use the reference sample battery C in Example 1 0 and the sample battery C to be tested 1 , to collect data during the charging phase, and to measure by combining constant current discharge (CC step) and constant voltage discharge (CV step). Among them, the charging current of constant current charging (CC working step) is represented by a multiplier, which is set to 0.1C, and the duration of constant voltage charging (CV working step) is set to 1 hour. Repeat the CC-CV steps until the potential of the test battery approaches the charge cut-off potential of 4.60V, and the reference battery C is at the same steady-state potential during the recording process. 0 and the battery under test C 1 change in specific capacity. According to the ratio of the specific capacity change of the reference battery and the battery under test at the same potential and the lithium-cobalt molar ratio of the reference sample, calculate the lithium-cobalt molar ratio of the lit...

Embodiment 3

[0060] Continue to use the reference sample battery C in Example 1 0 and the sample battery C to be tested 1 , Repeat the data collection in the discharge stage, and use the combination of constant current discharge (CC step) and constant voltage discharge (CV step) to measure. Wherein the design start potential and end potential of each stage are the same as in Example 1, and the constant current discharge rate and the holding time of the constant voltage discharge stage are changed in each stage, and the specific design values ​​are shown in the table below. Repeat the CC-CV steps until the potential of the test battery approaches the discharge cut-off potential of 3.0V, and the reference battery C is at the same steady-state potential during the recording process. 0 and the battery under test C 1 change in specific capacity. According to the ratio of the specific capacity change of the reference battery and the battery under test at the same potential and the lithium-cob...

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Abstract

The invention relates to a method for non-destructively evaluating a lithium-cobalt molar ratio in a lithium battery electrode, which comprises the following steps of: defining an active material of the lithium battery electrode as lithium cobalt oxide M1-n, selecting a lithium cobalt oxide standard sample M0 with a known lithium-cobalt molar ratio N0,wherein the molar ratio of lithium to cobalt in the lithium battery electrode is N1-n; manufacturing a reference electrode by adopting the same process as the lithium battery electrode, assembling the reference electrode and the lithium battery electrode into a battery according to the same method, then carrying out specific capacity testing under the same condition, wherein the measured specific capacities of the battery are Q0 and Q1-n respectively, and the lithium-cobalt molar ratio in the lithium battery electrode is N1-n = N0 * (Q1-n / Q0). The sample to be tested does not need to decompose the battery, the requirement for the sample amount is avoided, online nondestructive testing can be achieved, and the method is particularly suitable for evaluating the lithium-cobalt molar ratio in the cycle performance testing process. Meanwhile, man-made interference is small, and the operation is convenient. In addition, used reagents are remarkably reduced, and the environmental pollution and pollution emission of a test room are reduced.

Description

technical field [0001] The invention relates to the technical field of electrochemical measurement, in particular to a method for nondestructively evaluating the lithium-cobalt molar ratio in lithium battery electrodes. Background technique [0002] Lithium-ion batteries have been used in various fields of people's production and life since 1991. Especially in recent years, they have developed rapidly. They not only continue to consolidate their position in 3C products such as mobile phones and notebook computers, but also gradually become the main technical route in the field of electric vehicles. one. The main raw materials of lithium-ion batteries include positive electrode materials, negative electrode materials, separators, and electrolytes. At the same time, it also includes auxiliary materials such as conductive agent, binder, casing, current collector and electrode lead-out terminal. The electrochemical performance of lithium-ion batteries depends on maximizing the...

Claims

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Application Information

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IPC IPC(8): G01N27/416
CPCG01N27/416
Inventor 尹秉胜赖兰芳池毓彬李现利魏丽英
Owner XTC NEW ENERGY MATERIALS(XIAMEN) LTD
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