Multilayer composite negative electrode material, preparation method thereof, negative electrode sheet and lithium battery

A negative electrode material, multi-layer composite technology, applied in the direction of negative electrode, battery electrode, secondary battery, etc., to achieve the effect of improving the first efficiency, improving the cycle performance, and improving the specific capacity of the negative electrode

Active Publication Date: 2019-08-09
ZHUHAI COSMX BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

After the composite material combines simple silicon and carbon materials, it can slow down the volume expansion of the electrode material, improve the first charge and discharge efficiency and energy density of the battery to a certain extent, and increase the specific capacity of the battery, but there are still room for improvement

Method used

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  • Multilayer composite negative electrode material, preparation method thereof, negative electrode sheet and lithium battery
  • Multilayer composite negative electrode material, preparation method thereof, negative electrode sheet and lithium battery
  • Multilayer composite negative electrode material, preparation method thereof, negative electrode sheet and lithium battery

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preparation example Construction

[0030] Such as figure 1 Shown, the steps of the preparation method of silicon / silicon dioxide / carbon multilayer composite material of the present invention are as follows:

[0031] Multi-layer precursor preparation step: using silicon, silicon dioxide, carbon, and carbon as initial raw materials to prepare the first precursor layer, the second precursor layer, and the third precursor layer, wherein the first precursor layer is made of The silicon layer pressed from pure silicon is preferably nanowire silicon, the second precursor layer is a carbon layer pressed from carbon material, preferably nano-carbon material, and the third precursor layer is made of silicon dioxide and carbon material. It is a silicon dioxide / carbon mixed layer formed after mixing the initial raw materials, preferably using nano-polycrystalline silicon dioxide and nano-carbon materials; according to the ratio of the target product, the amount of materials in each layer is added, and an appropriate amount...

Embodiment 1

[0038]Mix 0.209g of silicon dioxide and 1.800g of artificial graphite, add 0.05g of polyvinyl butyral (binder), and then ball mill evenly, and the obtained uniform powder is used as silicon / silicon dioxide layer precursor powder , the SiO 2 / C mixed powder is pressed into flakes, and 0.200g of pure silicon and 0.900g of pure carbon powder are also pressed into flakes respectively, and then according to Si|SiO 2 / C|C sequentially molded into a multi-layer structure sheet, then put the mixed sheet into a sintering furnace, fill it with argon, heat up to 680°C and sinter for 13 hours to prepare a multi-layer precursor;

[0039] The multi-layer precursor is connected and drawn out with an electronically conductive material as the cathode, and the high-purity graphite rod is used as the anode. In the electrolytic furnace, the corundum crucible is used as the electrolytic cell, and 380 grams of calcium chloride (molten salt) is weighed and put into the ceramic crucible. Introduce a...

Embodiment 2

[0042] Mix 0.618g of silicon dioxide and 2.600g of artificial graphite, add 0.18g of polyvinyl butyral, and then ball mill evenly. The uniform powder obtained is used as silicon / silicon dioxide layer precursor powder, and SiO 2 / C mixed powder is pressed into flakes, and 0.800g of pure silicon and 0.200g of pure carbon powder are also pressed into flakes respectively, and then according to SiO 2 |SiO 2 / C|C sequentially molded into a sheet with a three-layer structure, then put the mixed sheet into a sintering furnace, fill it with argon, heat up to 850°C and sinter for 8 hours to prepare a multi-layer precursor;

[0043] Connect the multi-layer precursor with an electronically conductive material as the cathode, use the high-purity graphite rod as the anode, and use the stainless steel crucible as the electrolytic cell in the electrolytic furnace, weigh 400 grams of calcium chloride into the stainless steel crucible, and pour it into the crucible resistance furnace Put argon...

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Abstract

The invention provides a multilayer composite negative electrode material, a preparation method thereof, a negative electrode sheet and a lithium battery. The preparation method of the multilayer composite negative electrode material comprises the steps that silicon, silicon dioxide and carbon are used as raw materials to prepare a multilayer precursor; a silicon material is mixed with a binder toacquire a first precursor layer mixture; silicon dioxide, a carbon material and the binder are mixed to acquire a second precursor layer mixture; the carbon material is mixed with the binder to acquire a third precursor layer mixture; the first, second and third precursor layer mixtures are molded in the order of a silicon layer, a silicon dioxide/carbon mixed layer and a carbon layer, and then are sintered to acquire a multilayer precursor; and silicon dioxide in the multilayer precursor is reduced to monatomic silicon to acquire the multilayer composite negative electrode material. According to the invention, a denser solid electrolyte interface film can be generated during the first charge and discharge process; the volume expansion effect of the silicon material during the charge anddischarge process is suppressed; and the first efficiency of the battery, the specific capacity of the negative electrode and the cycle performance of the battery are improved.

Description

technical field [0001] The invention belongs to the technical field of power lithium-ion batteries, and in particular relates to a composite negative electrode material for power lithium-ion batteries. Background technique [0002] With the popularization of the application of new energy electric vehicles, people have higher and higher requirements for the battery life of power electric vehicles. The use of positive and negative electrode materials with high specific capacity on power batteries plays an extremely important role in improving battery life. At present, the anode materials of lithium-ion power batteries are mainly graphite materials, and the theoretical specific capacity of graphite is 372mAh / g. The specific capacity of graphite anode materials that have been mass-produced at this stage has reached more than 360mAh / g, basically reaching the upper limit of graphite materials. , it is difficult to meet people's demand for high energy density batteries at this sta...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/36H01M4/38H01M4/48H01M4/583H01M10/0525
CPCH01M4/13H01M4/366H01M4/386H01M4/48H01M4/583H01M10/0525H01M2004/027Y02E60/10
Inventor 赖冠全申红光刘城彭冲李俊义徐延铭
Owner ZHUHAI COSMX BATTERY CO LTD
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