Cathode active substance for lithium ion secondary battery, preparation method and lithium ion secondary battery

A negative electrode active material and secondary battery technology, which is applied to secondary batteries, battery electrodes, circuits, etc., can solve the problems of complex preparation methods, small specific capacity of the first discharge of batteries, and large average particle size of lithium chromium titanate. The effect of simple production process and high initial discharge specific capacity

Inactive Publication Date: 2012-01-11
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The present invention solves the technical problem that the preparation method of lithium chromium titanate is complicated in the prior art, the average particle size of the lithium chromium titanate prepared is relatively larg

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  • Cathode active substance for lithium ion secondary battery, preparation method and lithium ion secondary battery
  • Cathode active substance for lithium ion secondary battery, preparation method and lithium ion secondary battery
  • Cathode active substance for lithium ion secondary battery, preparation method and lithium ion secondary battery

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preparation example Construction

[0016] The invention provides a method for preparing a negative electrode active material containing nanometer lithium chromium titanate, the method comprising:

[0017] 1) After mixing titanium dioxide, chromium trioxide, a lithium source and a solvent, drying and removing the solvent to obtain a first mixture;

[0018] 2) mixing and drying the first mixture obtained in step 1 with a saturated solution of low-temperature molten salt to obtain a second mixture;

[0019] 3) Calcining the second mixture obtained in step 2 to remove the low-temperature molten salt, wherein the low-temperature molten salt is a salt that can melt under calcination conditions and does not react with other components in the mixture.

[0020] In step 1, the molar ratio of titanium dioxide, dichromium trioxide and lithium source is 2:1-2:1.05, and in a preferred case, the molar ratio of titanium dioxide, dichromium trioxide and lithium source is 2:1:1.05.

[0021] The method of mixing titanium dioxide...

Embodiment 1

[0035] (1) Preparation of nano-chromium lithium titanate

[0036] TiO 2 、Cr 2 o 3 and Li 2 CO 3According to the ratio of 2:1:1.05, put it in a 100ml ball mill jar, add 80ml of absolute ethanol, ball mill for 8 hours, and mix thoroughly. Dry and remove dehydrated alcohol, obtain the first mixture, the first mixture is dissolved in the saturated solution that is solute with LiCl again, wherein the weight ratio of the first mixture and LiCl is 1: 3, in a stirrer (ELE Yi Le electromechanical, EBF -22) Stir for 5 minutes at a rotational speed of 1100r / min, mix well, and dry at 100°C for 24 hours to obtain a second mixture, heat the second mixture to 600°C to melt the salt, and After 12 h at temperature, the Li was removed by repeated washing with distilled water. + and Cl - , and the washed sample was dried in a vacuum oven at 100° C. for 24 hours to obtain nano-chromium lithium titanate sample A1. The morphology of the synthesized product was observed with a JSM-5610LV sca...

Embodiment 2

[0045] (1) Preparation of nano-chromium lithium titanate

[0046] TiO 2 、Cr 2 o 3 and Li 2 CO 3 Put it in a ball mill jar according to the ratio of 2:1:1, add it into a 100ml ball mill jar at the same time, add 80ml of absolute ethanol as a solvent, ball mill for 8 hours, mix thoroughly, dry and remove the solvent to obtain the first mixture. Dissolving the first mixture in a saturated solution with KCl as the solute, wherein the weight ratio of the first mixture to KCl is 1:4, and then drying at 100° C. for 24 hours to obtain a second mixture, which is heated to Melt KCl at 700°C, and then keep it at 700°C for 12 hours, then wash repeatedly with distilled water to remove K + and Cl - , and the washed sample was dried in a vacuum oven at 100° C. for 24 hours to obtain nano-chromium lithium titanate sample A2. Observing the morphology of the synthesized product with a JSM-5610LV scanning electron microscope (SEM), the product is an octahedral structure with an average pa...

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Abstract

The invention provides a cathode active substance for lithium ion battery and a preparation method thereof. The method comprises the steps of 1) after titanium dioxide, chromic oxide, a lithium source and a solvent are mixed, conducting drying to remove the solvent to obtain first mixtures; 2) mixing the first mixtures obtained at the step 1 with the saturated solution of low-temperature fused salt and conducting drying to obtain second mixtures; and 3) calcining the second mixtures obtained at the step 2 and removing the low-temperature fused salt to obtain nanometer chromium lithium titanate, wherein the low-temperature fused salt is salt which can be fused under the condition of calcination and does not react with other components in the mixtures. The average grain size of the cathode active substance, i.e. the nanometer chromium lithium titanate prepared through the method provided by the invention is 200-250nm and the cathode active substance has an octahedral structure. The battery which is prepared by using the cathode active substance, i.e. the nanometer chromium lithium titanate provided by the invention has a good initial discharge specific capacity.

Description

technical field [0001] The invention relates to a negative electrode active material for a lithium ion secondary battery, a preparation method, and a lithium ion secondary battery using the negative electrode active material. Background technique [0002] With the rapid development of information technology, the requirements of various electronic products for power supply are constantly increasing. Due to the advantages of high energy density, long cycle life, and no memory effect, lithium-ion batteries have always been a hot spot in research and development. [0003] Most commercial lithium-ion battery anode materials use carbon materials, but the contact reaction between the anode carbon and the organic electrolyte is one of the important factors that cause the battery capacity decay of carbon anode materials in the current commercial application of lithium batteries. The volume expansion of the negative electrode material causes the material powder to fall off from the c...

Claims

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Application Information

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IPC IPC(8): H01M4/1391H01M4/485H01M4/525H01M10/0525
CPCY02E60/122Y02E60/10
Inventor 郭姿珠
Owner BYD CO LTD
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