Si@C lithium-ion battery negative electrode material of core-shell structure and preparation method thereof

A lithium-ion battery, core-shell structure technology, applied in the direction of battery electrodes, secondary batteries, structural parts, etc., can solve the problem that it is difficult to produce a carbon coating layer with a pore structure, it is difficult to achieve large-scale production, and there are few reports on modification, etc. problems, to achieve the effect of being suitable for large-scale production, good product consistency, and improving rate performance and cycle performance

Active Publication Date: 2017-11-17
XUZHOU NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, most of the reported carbon-coated silicon composites use glucose, sucrose, polystyrene, epoxy resin, etc.
Moreover, the existing preparation methods of this composite material, such as chemical vapor deposition, pyrolysis, etc., are all cumbersome in process, poor in process controllability, and difficult to achieve large-scale production, so they need to be improved urgently
In addition, researchers have done a lot of research on the use of metal-organic frameworks and their derived carbon materials as electrode materials for lithium-sulfur batteries, but there are few reports on their use as modification of Si anode materials.

Method used

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  • Si@C lithium-ion battery negative electrode material of core-shell structure and preparation method thereof
  • Si@C lithium-ion battery negative electrode material of core-shell structure and preparation method thereof
  • Si@C lithium-ion battery negative electrode material of core-shell structure and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] A. Surface activation of nano-silicon: First, ultrasonically disperse 200 mg of spherical nano-silicon with a diameter of 50-70 nm into 40 ml of 30wt% H 2 o 2 Medium, and the ultrasonic power is 100W, and the time is 20min.

[0033] Then stir at room temperature for 0.5 h to fully activate the spherical nano-silicon.

[0034] After filtering, the filtered product was washed three times with deionized water and absolute ethanol respectively, and then vacuum-dried for 12 hours at a vacuum degree of 0.05 MPa and 55° C. to obtain activated nano-silicon.

[0035]B. Preparation of Si@ZIF-67 precursor: Weigh 20 mg of the above-mentioned activated nano-silicon, ultrasonically disperse it into 60 mL of a mixed solution of methanol and ethanol with a volume ratio of 1:1, add 0.2 g of polyvinylpyrrolidone and 0.07 g of hexahydrate Cobalt nitrate, and continued ultrasonic stirring for 1 h to obtain a suspension.

[0036] Then, because the precursor of Si@ZIF-67 can be generated ...

Embodiment 2

[0041] A. Surface activation of nano-silicon: First, ultrasonically disperse 200mg of spherical nano-silicon with a diameter of 50-70nm into 40 ml of 30wt% H 2 o 2 Medium, and the ultrasonic power is 100W, and the time is 2min.

[0042] Then stir at room temperature for 3 h to fully activate the spherical nano-silicon.

[0043] After filtering, the filtered product was washed three times with deionized water and absolute ethanol respectively, and then vacuum-dried for 10 hours at a vacuum degree of 0.1 MPa and 60° C. to obtain activated nano-silicon.

[0044] B. Preparation of Si@ZIF-67 precursor: Weigh 20 mg of the above-mentioned activated nano-silicon, ultrasonically disperse it into 60 mL of a mixed solution of ethanol and methanol mixed at a volume ratio of 1:2, add 0.2 g polyvinylpyrrolidone and 0.5 g Cobalt chloride hexahydrate, continue ultrasonic stirring for 3 h to obtain a suspension.

[0045] Then take by weighing 0.342g 2-methylimidazole and be dissolved in 60m...

Embodiment 3

[0051] A. Surface activation of nano-silicon: first disperse 150mg of spherical nano-silicon with a diameter of 50-70nm into 40ml of 30wt% H 2 o 2 Medium, and the ultrasonic power is 100W, and the time is 10min.

[0052] Then stir at room temperature for 3 h to fully activate the spherical nano-silicon.

[0053] After filtering, the filtered product was washed three times with deionized water and absolute ethanol respectively, and then vacuum-dried for 10 hours at a vacuum degree of 0.1 MPa and 60° C. to obtain activated nano-silicon.

[0054] B. Preparation of Si@MIL-88(Fe) precursor: Weigh 20 mg of the above-mentioned activated nano-silicon, ultrasonically disperse it into 60 mL of a mixed solution of ethanol and dimethylformamide mixed at a volume ratio of 1:1, add 0.025 g ferric nitrate nonahydrate, and continue ultrasonic stirring for 2 h. Then add 0.018g of terephthalic acid, continue to stir for 0.5h, transfer the resulting solution to the reactor, and keep it warm f...

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Abstract

The invention discloses an Si@C lithium-ion battery negative electrode material of a core-shell structure and a preparation method thereof. The material uses a metal organic frame compound MOFs as a carbon source, and comprises a core and a cladding layer, the core is spherical nanometer silicon, and the cladding layer is an amorphous carbon layer of a porous structure. The material is prepared through the following steps: A, surface activation of nanometer silicon; B, preparation of an Si@MOFs precursor; and C, preparation of Si@C. The carbon layer in the obtained composite material is of good electrical conductivity and an abundant porous structure, quick transfer of electrons and diffusion of electrolyte ions are facilitated, the volume expansion of the core in the electrochemical reaction process can be effectively buffered, and the composite material has excellent electrochemical performance; and the preparation method is simple in production technology, easily controlled for reaction conditions and environmentally-friendly, and is beneficial for performance optimization and industrial production of silicon negative electrode materials.

Description

technical field [0001] The invention relates to a lithium ion battery negative electrode material and a preparation method thereof, in particular to a core-shell structure Si@C composite material using metal organic framework compounds MOFs as a carbon source and a preparation method thereof. Background technique [0002] A lithium-ion battery is a secondary battery (rechargeable battery) that operates primarily by moving lithium ions between positive and negative electrodes. During the charging and discharging process, Li + Intercalation and deintercalation back and forth between two electrodes: when charged, Li + It is deintercalated from the positive electrode, inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. With the rapid development of portable electronic devices and new energy vehicles, the development of lithium-ion battery electrode materials with high energy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/366H01M4/386H01M4/583H01M10/0525Y02E60/10
Inventor 王庆红郭璨朱俞宣卢晗李丹
Owner XUZHOU NORMAL UNIVERSITY
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