High-coulombic-efficiency negative electrode active material of carbon-coated lithium-rich lithium titanate of lithium ion battery and preparation method for high-coulombic-efficiency negative electrode active material of carbon-coated lithium-rich lithium titanate

A negative electrode active material, a technology for lithium ion batteries, applied in battery electrodes, circuits, electrical components, etc., can solve problems such as failure of lithium-rich lithium titanate, eliminate the irreversible capacity loss of the first cycle, simple process flow, and easy industrialized production Effect

Inactive Publication Date: 2012-07-11
HUNAN UNIV
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  • Abstract
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AI Technical Summary

Problems solved by technology

But these lithium titanate Li 4 Ti 5 o 12 Intercalation of lithium into lithium-rich lithium titanate Li 4+x Ti 5 o 12 The methods are all realized by electrochemical means, not only the whole preparation needs to be strictly carried out under the protective atmosphere of argon, but also the obtained lithium-rich lithium titanate Li 4+x Ti 5 o 12 After exposure to the atmosphere, lithium-rich lithium titanate quickly reacted with O in the air 2 , CO 2 and H 2 O and other reactions, so that the lithium-rich lithium titanate is completely invalid, that is, this lithium-rich lithium titanate is not protected by a carbon layer, and it is an intermediate form, but a stable material in the abnormal state.

Method used

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  • High-coulombic-efficiency negative electrode active material of carbon-coated lithium-rich lithium titanate of lithium ion battery and preparation method for high-coulombic-efficiency negative electrode active material of carbon-coated lithium-rich lithium titanate
  • High-coulombic-efficiency negative electrode active material of carbon-coated lithium-rich lithium titanate of lithium ion battery and preparation method for high-coulombic-efficiency negative electrode active material of carbon-coated lithium-rich lithium titanate
  • High-coulombic-efficiency negative electrode active material of carbon-coated lithium-rich lithium titanate of lithium ion battery and preparation method for high-coulombic-efficiency negative electrode active material of carbon-coated lithium-rich lithium titanate

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Lithium source Li 2 CO 3 , titanium source TiO 2 Mix the three raw materials with the carbon source mesophase pitch according to the following addition ratio, and the molar ratio of Li:Ti is 4.5:5. Add Li 2 CO 3 and TiO 2 , the amount of mesophase pitch added is Li 2 CO 3 and TiO 2 3% of the sum of the mass of the two materials; then fully mixed by ball milling, and in an argon atmosphere, the temperature was raised to 850°C for 15 hours; finally cooled to room temperature.

[0019] Carbon-coated Li was prepared by the above method 4+x Ti 5 o 12 Composite powder material, where x is 0.49. Prepare it as a lithium-ion battery negative electrode active material into a lithium-ion button battery, test its electrical properties, the results are as follows figure 1 shown. one of them figure 1 The charge and discharge cycle results of a show that the first charge specific capacity of the battery is 159.3mAhg -1 (delithiation), and the first discharge specific cap...

Embodiment 2

[0021] Lithium source LiOH, titanium source TiO 2 and the three raw materials of carbon source phenolic resin are mixed uniformly according to the following addition ratio, and the molar ratio of Li:Ti is 5:5. Add LiOH and TiO 2 , the amount of phenolic resin added is LiOH and TiO 2 5% of the sum of the mass of the two materials; then thoroughly mixed by ball milling, and then in an argon atmosphere, the temperature was raised to 900°C and kept at the temperature for 12 hours; finally cooled to room temperature.

[0022] Carbon-coated Li was prepared by the above method 4+x Ti 5 o 12 Composite powder material, where x is 0.83. Prepare it as a lithium-ion battery negative electrode active material into a lithium-ion button battery, test its electrical properties, the results are as follows figure 2 shown. one of them figure 2 The charge and discharge cycle results of a show that the first charge specific capacity of the battery is 161.4mAhg -1 (delithiation), and the ...

Embodiment 3

[0024] Lithium source Li 2 CO 3 , titanium source TiO 2 and the carbon source citric acid are ball-milled into powder materials and then mixed uniformly according to the following addition ratio. The molar ratio of Li:Ti is 6:5. 2 CO 3 and TiO 2 , the amount of citric acid added is Li 2 CO 3 50% of the mass; then under a nitrogen atmosphere, the temperature was raised to 800° C. and then kept at a constant temperature for 20 hours; finally cooled to room temperature.

[0025] Carbon-coated Li was prepared by the above method 4+x Ti 5 o 12 Composite powder material, where x is 2.0. Prepare it as a lithium-ion battery negative electrode active material into a lithium-ion button battery, and test its electrochemical performance. The results are as follows: image 3 shown. in image 3 The charge and discharge cycle results of a show that the first discharge specific capacity of the battery is 0mAhg -1 (lithium insertion), and the specific capacity of the first charge ...

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Abstract

The invention provides a negative electrode active material of a lithium ion battery. The negative electrode active material is a powder composite material prepared from a carbon-coated compound of which the molecular formula is Li4+xTi5O12, wherein x is more than 0 and less than or equal to 3. A method for preparing the negative electrode active material comprises the following steps of: fully mixing three types of powder materials of a lithium source, a titanium source and a carbon source in an inert-gas-protected atmosphere, and performing high-temperature solid-phase sintering; and cooling to the room temperature. The negative electrode active material is a lithium-rich lithium titanate material with a stable structure in the air at normal temperature and normal pressure, is convenient to manufacture, use and store, and can be popularized and used on a large scale; and for the lithium ion battery prepared from the negative electrode active material, the first cycle coulombic efficiency is 100 percent higher than a theoretical value, and the first cycle irreversible capacity loss of the battery is eliminated. The method for preparing the negative electrode active material is moderate in condition and simple in technological process, can be very easily applied to industrial production, and is environment-friendly.

Description

technical field [0001] The invention relates to a lithium ion battery negative electrode material and a preparation method thereof, in particular to a negative electrode active material carbon-coated lithium-rich lithium titanate and a preparation method thereof. Background technique [0002] Lithium titanate Li with spinel structure 4 Ti 5 o 12 As a negative electrode material, it has the advantages of long cycle life and high safety, which has attracted the attention and attention of researchers. Li 4 Ti 5 o 12 The lithium storage mechanism is: [0003] [0004] After fully intercalating lithium, the spinel-structured Li 4 Ti 5 o 12 Li transformed into a rock-salt phase structure 7 Ti 5 o 12 , the theoretical capacity is 175mAhg -1 . The kinetics of this phase transition process is highly reversible, and the volume change before and after the phase transition is less than 1%, so Li 4 Ti 5 o 12 Known as a "zero strain" material, it has a very long cycle ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/485
CPCY02E60/122Y02E60/10
Inventor 陈玉喜张林
Owner HUNAN UNIV
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