Anode active material for nonaqueous electrolyte secondary battery comprising silicon oxide composite and method for producing same

A negative electrode active material and non-aqueous electrolyte technology, which is applied in the field of negative electrode active materials for non-aqueous electrolyte secondary batteries containing silicon oxide composites and its preparation, and can solve the problem of reduced life characteristics, reduced life characteristics, and loss of conductive paths And other issues

Pending Publication Date: 2020-07-14
DAEJOO ELECTRONICS MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, silicon (Si), tin (Sn), aluminum (Al), antimony (Sb) and other metals can cause large volume expansion and contraction during the alloying / non-alloying reaction with lithium (Li), so they have the following Problems, namely, reduction in lifetime characteristics due to undifferentiation, loss of conductive path, etc.
In particular, in terms of discharge capacity (4200mAh / g) and discharge voltage (0.4V), silicon (Si) is the most suitable material for high-capacity negative electrode materials, but when lithium (Li) ions are inserted (charged) into the material The large volume expansion of about 400% can lead to the degradation of the active material (pulverization), resulting in a sharp drop in lifetime characteristics

Method used

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  • Anode active material for nonaqueous electrolyte secondary battery comprising silicon oxide composite and method for producing same
  • Anode active material for nonaqueous electrolyte secondary battery comprising silicon oxide composite and method for producing same
  • Anode active material for nonaqueous electrolyte secondary battery comprising silicon oxide composite and method for producing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0070] Example 1. Preparation of silicon oxide composites containing magnesium

[0071] Heat-treat 15kg of silicon powder and silicon dioxide (SiO 2 ) powder powder and 1.5kg of magnesium, the above silicon, silicon dioxide (SiO 2 ) of the mixed powder of silicon oxide vapor and magnesium vapor are simultaneously generated to react in the gas phase, cooled at a temperature of 700°C and then precipitated, and then crushed and classified with a jet mill to obtain an average particle size (D 50 ) is magnesium-silicon oxide composite powder of 6.3 μm.

[0072] In order to form a carbon-containing coating layer, the recycled silicon oxide composite powder containing magnesium is placed in argon (Ar) and methane (CH 4 ) in a mixed gas, and processed by chemical vapor deposition (CVD) for 2 hours, thereby preparing a silicon oxide composite (sample 1).

[0073] It was confirmed from the above silica composite (sample 1) containing magnesium that the BET specific surface area was ...

Embodiment 2

[0074] Example 2. Preparation of silica composites containing magnesium

[0075] Except for precipitation after cooling at a temperature of 800°C, a silicon oxide composite (sample 2) containing 9% by weight of magnesium was prepared by the same method as in Example 1 above, and a carbon content of 5% by weight was prepared. Percent carbon coating layer of silicon oxide composite powder.

[0076] It was confirmed from the above silica composite (sample 2) containing magnesium that the BET specific surface area was 6.2m 2 / g, the specific gravity is 2.3g / cm 3 , average particle size (D 50 ) was 6.5 μm, and the silicon crystal size measured by X-ray diffraction analysis (CuKα) was 8 nm.

Embodiment 3

[0077] Example 3. Preparation of silica composites containing magnesium

[0078] Except for precipitation after cooling at a temperature of 900°C, a silicon oxide composite (sample 3) containing 4% by weight of magnesium was prepared by the same method as in Example 1 above, and a carbon content of 10% by weight was prepared. Percent carbon coating layer of silicon oxide composite powder.

[0079] It was confirmed from the above silica composite (sample 3) containing magnesium that the BET specific surface area was 6.3m 2 / g, the specific gravity is 2.4g / cm 3 , average particle size (D 50 ) was 6.2 μm, and the size of silicon crystals measured by X-ray diffraction analysis (CuKα) was 11 nm.

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Abstract

The present invention relates to an anode active material for a nonaqueous electrolyte secondary battery. An anode active material for a nonaqueous electrolyte secondary battery, according to an embodiment of the present invention, comprises a silicon oxide composite including silicon, silicon oxide (SiOx, 0 < x <= 2), and magnesium silicate, wherein the silicon oxide composite includes pores having a size of 50 nm to 300 nm thereinside. The anode active material for a nonaqueous electrolyte secondary battery comprising the silicon oxide composite according to the present invention solves a swelling problem because the internal pores serve to buffer swelling during a charging process, and allows stress caused by the swelling and contraction occurring during charging and discharging processes to be concentrated in the internal pores such that volume swelling is controlled efficiently, and therefore, the lifetime characteristics of a lithium secondary battery can be improved.

Description

technical field [0001] The present invention relates to a negative electrode active material for a nonaqueous electrolyte secondary battery containing a silicon oxide compound and a preparation method thereof. Background technique [0002] Recently, lithium secondary batteries, which are attracting attention as power sources for portable and small electronic devices, are high energy density batteries. By using an organic electrolyte, they can release a discharge voltage more than twice that of conventional alkaline aqueous batteries. [0003] LiCoO is mainly used as a positive electrode active material for lithium secondary batteries 2 , LiMn 2 o 4 、LiNi 1-x co x o 2 (0<x<1) and other oxides composed of transition metals that can intercalate lithium can be used as negative electrode active materials in various forms of carbons including artificial graphite, natural graphite, and hard carbon that can intercalate and desorb lithium. Material. [0004] Although gra...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/485H01M4/58H01M4/62H01M10/0525C01B33/02C01B33/113C01B33/22
CPCY02E60/10C01B33/02H01M10/0525C01B33/18H01M4/483H01M4/5825H01M4/386H01M2004/021H01M2004/027H01M4/366H01M4/625H01M4/131H01M4/134H01M4/1391H01M4/1395H01M4/0428H01M4/0471H01M4/364H01M4/368H01M4/485C01B33/113C01B33/22H01M4/04H01M4/48
Inventor 吴性旻
Owner DAEJOO ELECTRONICS MATERIALS CO LTD
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