Cathode active material and preparation method and lithium ion battery thereof

A negative electrode active material, water-soluble technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of poor battery charge and discharge efficiency and cycle performance, uneven tin dispersion, etc., to reduce decomposition and ensure cycle performance , Improve the effect of charging and discharging efficiency and cycle performance

Active Publication Date: 2012-09-26
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The invention solves the technical problem that tin in the negative electrode active material in the prior art is unevenly dispersed on the graphite surface and is easy to react with the electrolyte, resulting in poor battery charging and discharging efficiency and cycle performance

Method used

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  • Cathode active material and preparation method and lithium ion battery thereof
  • Cathode active material and preparation method and lithium ion battery thereof
  • Cathode active material and preparation method and lithium ion battery thereof

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preparation example Construction

[0028] The present invention also provides a preparation method of the negative electrode active material, comprising the following steps:

[0029] 1) Surface treatment of graphite;

[0030] 2) Mix the surface-treated graphite with a water-soluble aluminum compound, and then add a metal salt solution to obtain a mixed system; the metal salt solution contains a water-soluble tin salt, and selectively contains a water-soluble M salt; Chemically active metal elements;

[0031] 3) Add water-soluble alkaline substances to the mixed system in step 2), until the precipitation is complete, and dry to obtain the precursor;

[0032] 4) Sintering the precursor to obtain the negative electrode active material.

[0033] According to the method of the present invention, the surface treatment of graphite is known to those skilled in the art, that is, immersing graphite in acid or alkali to acidify or alkalinize. Acidification or alkalization treatment, on the one hand, removes incompatibl...

Embodiment 1

[0052] (1) Blend 200g of sodium hydroxide with a concentration of 50wt% and 50g of graphite, heat to 60°C, stir for 3h, wash and filter with deionized water, and dry at 60°C for 12h to obtain alkalized graphite;

[0053] (2) Weigh 0.04mol SnSO 4 Dissolve in water to make 400mL metal salt solution; Add the alkalized graphite to the solution containing 0.01mol / L citric acid and 0.005mol / L AlCl 3 1L of mixed solution, then add metal salt solution, blend and stir to obtain a mixed system;

[0054] (3) Heat the mixed system in a water bath to 80°C, add 0.1mol / LNH dropwise to the mixed system 4 HCO 3 The solution was stirred at a constant temperature of 80°C for 2 hours until the precipitation was complete. After filtration, the precipitate was vacuum-baked at 80°C for 12 hours to obtain a precursor sample, which was designated as A1;

[0055] (4) Vacuum sintering the precursor sample A1 at 800° C. for 10 h to obtain the negative electrode active material sample of this embodimen...

Embodiment 2

[0064] (1) Blend 200g of nitric acid with a concentration of 34wt% and 50g of graphite, heat to 60°C, stir for 3h, wash and filter with deionized water, and dry at 60°C for 12h to obtain acidified graphite;

[0065] (2) Weigh 0.04mol SnSO 4 and 0.06mol CoCl 3 Dissolve in water to make 400mL metal salt solution; add the acidified graphite to the solution containing 0.01mol / L glucose and 0.005mol / L 31L of mixed solution, then add metal salt solution, blend and stir to obtain a mixed system;

[0066] (3) Heat the mixed system in a water bath to 80°C, and add 0.1mol / LNH dropwise to the mixed system 4 HCO 3 The solution was stirred at a constant temperature of 80°C for 2 hours until the precipitation was complete. After filtration, the precipitate was vacuum-baked at 80°C for 12 hours to obtain a precursor sample, which was designated as A2;

[0067] (4) The precursor sample A2 was sintered at 800° C. for 10 h under the protection of nitrogen atmosphere to obtain the negative e...

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Abstract

The invention provides a cathode active material which has a core shell structure; the core shell structure comprises an inner core and an outer shell, and the inner core is graphite; wherein the outer shell is composite particles, and comprises a first shell layer and a second shell layer; the first shell layer is tin or tin alloy, and is coated on the surface of the inner core; the second shell layer is alumina, and is coated on the surface of the tin or tin alloy. The invention also provides a preparation method of the cathode active material and a lithium ion battery containing the cathode active material. The lithium ion battery provided by the invention has good charge and discharge performance and cycle performance.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a negative electrode active material, a preparation method thereof and a lithium ion battery. Background technique [0002] Lithium-ion batteries have the advantages of high voltage, large specific energy, and good safety performance. At present, the negative electrode active material of commercialized lithium-ion batteries is mainly graphite. During the process of intercalating and removing lithium, the volume change of graphite is small, so it has good cycle performance. Graphite via LiC 6 Compounds reversibly store Li + , and its theoretical mass specific capacity is only 372 mA·h / g. Compared with graphite negative electrodes, tin-based negative electrode active materials have higher specific capacity, for example, the theoretical capacity of metal tin is as high as 994mAh / g. However, during the charge and discharge process, the volume of metal tin will cha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/139H01M10/0525
CPCY02E60/122Y02E60/10
Inventor 谢呈德李世彩
Owner BYD CO LTD
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