Binder-free porous silicon/carbon composite electrode and application thereof

A binder-free, porous silicon technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems of insignificant improvement in conductivity, shedding of active components, and deterioration of electrode performance, and achieve excellent electronic conductivity and environmental protection. The effect of small influence and excellent binding force

Active Publication Date: 2016-07-27
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this process, the combination of the active conductive material graphite and silicon dioxide with the help of a binder has a great impact on the performance of the electrode in the later stage. On the one hand, if the binder is added too little, the binding force between graphite and silicon dioxide If it is too small, the volume expansion caused by delithiation and intercalation of lithium usually causes the active components to fall off from the surface of the current collector, making the electrode performance deteriorate rapidly; on the other hand, if the binder is added too much, because the binder itself is not conductive, As a result, the overall conductivity of the silicon-based composite material is not significantly improved, which seriously affects the performance of the electrode

Method used

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  • Binder-free porous silicon/carbon composite electrode and application thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] First, use sandpaper with gradient particle size (400#, 600#, 1000#) to polish the copper foil or nickel foil substrate in turn until it is bright without obvious scratches, remove the surface oxide with 1mol / L dilute hydrochloric acid, and then use absolute ethanol and deionized water in order to degrease and wash, then dry with hot air; gradually add 50mL of absolute ethanol, 50mL of 0.05mol L to the beaker -1 Potassium nitrate, 1mL orthomethyl silicate (TMOS), with 2.0mol·L -1 HNO 3 Adjust the pH to about 6.0, and stir at room temperature for 6 h for later use. Polished copper foil or nickel foil cathode, 2*2cm 2 The platinum sheet is used as the anode, the Ag / AgCl is used as the reference electrode, the distance between the electrodes is controlled at 1cm, and the current density is controlled at -0.1mA·cm -2 Electrodeposition was performed, and the deposition time was 1000s. After the deposition was completed, the working electrode was rinsed with deionized wate...

Embodiment 2

[0044] First, use sandpaper with gradient particle size (400#, 600#, 1000#) to polish the copper foil or nickel foil substrate in turn until it is bright without obvious scratches, remove the surface oxide with 1mol / L dilute hydrochloric acid, and then use absolute ethanol and deionized water in order to degrease and wash, then dry with hot air; gradually add 50mL of absolute ethanol, 50mL of 1.0mol L to the beaker -1 Potassium nitrate, 5mL tetraethyl orthosilicate (TEOS), with 0.5mol·L -1 Adjust the pH to about 2.0 with HAc, stir at room temperature for 2 h and set aside. Use polished copper foil or nickel foil as the cathode, 2*2cm 2 Platinum sheet is the anode, Ag / AgCl is the reference electrode, the electrode spacing is controlled at 10cm, and the current density is controlled at -5mA cm -2 Electrodeposition was carried out, and the deposition time was 30s. After the deposition was completed, the working electrode was rinsed with deionized water and then dried at 40° C. ...

Embodiment 3

[0048] First, use sandpaper with gradient particle size (400#, 600#, 1000#) to polish the copper foil or nickel foil substrate in turn until it is bright without obvious scratches, remove the surface oxide with 1mol / L dilute hydrochloric acid, and then use absolute ethanol and deionized water in order to degrease and wash, then dry with hot air; gradually add 100mL absolute ethanol, 100mL0.2mol·L -1 Sodium nitrate, 10mL orthomethyl silicate (TMOS), with 1.0mol·L -1 Adjust the pH to about 6.0 with HCl, stir at room temperature for 6 h and set aside. Use polished copper foil or nickel foil as the cathode, 2*2cm 2 Platinum sheet is the anode, Ag / AgCl is the reference electrode, the electrode spacing is controlled at 1cm, and the current density is controlled at -1mA cm -2 Electrodeposition was performed, and the deposition time was 600s. After the deposition was completed, the working electrode was rinsed with deionized water and then dried at 40° C. to obtain a micronano oxide...

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Abstract

The invention discloses a binder-free porous silicon/carbon composite electrode and an application thereof. The composite electrode is prepared by the following steps of (1) mixing absolute ethyl alcohol, nitrate or perchlorate water solution and silicate alkyl ester, then adjusting pH to 2.0-6.0, and stirring to obtain a precursor solution; (2) performing surface oxide removing and oil removing on a copper foil substrate or a nickel foil substrate; (3) taking the processed copper coil substrate or the nickel foil substrate as working electrodes, and putting the working electrodes in an electrode groove loaded with the precursor solution, and taking a platinum sheet or graphite as a counter electrode to carry out electro-deposition to obtain a micro-nano silicon oxide coating on the surface of the copper coil substrate or the nickel foil substrate; (4) carrying out magnesiothermic reduction on the copper coil substrate or the nickel foil substrate coated with the micro-nano silicon oxide coating to obtain a copper foil or a nickel foil with a porous silicon-based material on the surface; and (5) carrying out chemical vapor deposition on the copper foil or the nickel foil with the porous silicon-based material on the surface to obtain the binder-free porous silicon/carbon composite electrode. The porous silicon/carbon composite electrode can be applied to the negative electrode of a lithium ion battery.

Description

(1) Technical field [0001] The invention relates to a binder-free porous silicon / carbon composite electrode and its application as a lithium ion battery negative electrode. (2) Background technology [0002] Lithium-ion batteries play an important role in people's daily life, and can be seen everywhere in the fields of communication equipment, electronic instruments, and vehicles. With the advancement of technology, the rapid development of electrical equipment has put forward higher requirements on the performance of lithium-ion batteries, but in fact, industrialized lithium-ion batteries have not made substantial breakthroughs in terms of performance stability and specific capacity. At present, commercially available lithium-ion batteries generally use graphite (theoretical specific capacity 372mAh / g) as the negative electrode material of the battery. Although graphite anode material has a stable charge-discharge platform and excellent cycle performance, it is still diffi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/134H01M4/1395
CPCH01M4/134H01M4/1395H01M2004/021Y02E60/10
Inventor 伍廉奎夏杰唐谊平曹华珍侯广亚郑国渠
Owner ZHEJIANG UNIV OF TECH
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