Doped multi-layer core-shell silicon-based composite material for lithium ion battery and preparation method thereof

A silicon-based composite material, lithium-ion battery technology, applied in nanotechnology for materials and surface science, battery electrodes, secondary batteries, etc., can solve problems such as poor rate performance, low first Coulomb efficiency, and short cycle life. , to achieve the effect of small size, alleviating volume effect, and inhibiting expansion

Active Publication Date: 2019-04-09
BERZELIUS (NANJING) CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to provide a doped polycarbonate for lithium-ion batteries for the technical shortcomings of the current silicon-based negative electrode materials, such as low coulombic efficiency, poor rate performance, and short cycle life, when they are applied to lithium-ion batteries. Layered core-shell silicon-based composites and an efficient construction method for large-scale preparation

Method used

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  • Doped multi-layer core-shell silicon-based composite material for lithium ion battery and preparation method thereof
  • Doped multi-layer core-shell silicon-based composite material for lithium ion battery and preparation method thereof
  • Doped multi-layer core-shell silicon-based composite material for lithium ion battery and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0078] Weigh 1000 g of silicon oxide particles with a median particle size of 6 μm (atomic ratio of silicon and oxygen is 1:1) and place them in a CVD furnace, and raise the temperature to 900 °C at a rate of 20 °C / min under the protection of an argon atmosphere. After the temperature was raised to 900° C., ammonia gas with a gas velocity of 300 ccm was passed into the furnace for 60 minutes to perform nitrogen doping on the silicon oxide compound particles. Subsequently, the acetylene gas with a gas velocity of 300 ccm was passed into the furnace for 30 minutes after continuing to keep at 900° C. for 30 minutes under an argon atmosphere. Subsequently, keep at 900° C. for 60 minutes under an argon atmosphere and then lower to room temperature to obtain carbon-coated nitrogen-doped silicon oxide particles. During the whole process, argon is passed into the CVD furnace at a gas velocity of 500 ccm. The resulting carbon-coated nitrogen-doped silicon oxide particles are passed thr...

Embodiment 2

[0085] Compared with Example 1, Example 2 uses phosphine gas instead of ammonia gas when the silicon oxide compound particles are element-doped by high-temperature CVD, and the remaining parameter conditions in the entire CVD process are the same as those in Example 1. And after the reaction, carbon-coated phosphorus-doped silicon-oxygen compound particles were obtained. 1000g of carbon-coated phosphorus-doped silicon oxide particles, aluminum nitrate nonahydrate, sucrose and polyvinylpyrrolidone were uniformly dispersed in 4000ml of deionized water by high-speed stirring at a mass ratio of 10:2:1:0.1, followed by spray drying. The air inlet temperature is 150°C, the outlet temperature is 105°C, the rotation speed of the rotary atomizing nozzle is 350Hz, and the feed rate is 100g / min. The spray-dried product was transferred to a chamber furnace, and the temperature was raised to 800°C at a rate of 10°C / min under a high-purity nitrogen atmosphere, and then kept at 800°C for 4 h...

Embodiment 3

[0089] Weigh 1000g of silicon oxide compound particles with a median particle size of 6 μm (atomic ratio of silicon to oxygen is 1:1) and 200g of ammonium hypophosphite and mix them uniformly in a drying room with a humidity below 20%. The resulting mixture was milled in a ball mill with zirconium beads with a diameter of 0.8 mm under a protective atmosphere for 2 hours, then transferred to a tube furnace, and then heated to 900 °C at a rate of 10 °C / min under an argon atmosphere and kept for 4 hours. Hours and then naturally cooled to room temperature to obtain silicon oxide compound particles doped with phosphorus. The obtained particles and petroleum asphalt were uniformly mixed in a heating VC mixer at a mass ratio of 10:1 to achieve asphalt coating, and then the temperature was raised to 900°C at a rate of 10°C / min in a box furnace with a high-purity nitrogen atmosphere and kept for 2 hours, then naturally cooled to room temperature and passed through a 500-mesh sieve to ...

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Abstract

The present invention relates to a doped multi-layer core-shell silicon-based composite material for a lithium ion battery, and a preparation method thereof. Other than being doped with a necessary lithium element, the material is also doped with at least a non-metallic element and a metal element; the material has a structure in which a silicon oxide particle doped with elements is taken as a core, and a multilayer composite film which is tightly coated on the surface of the core particle is taken as a shell; the core particle contains uniformly dispersed monoplasmatic silicon nanoparticles,the content of doping elements gradually decreases from the outside to the inside without a clear interface, and a dense lithium silicate compound is formed on the surface of the core particle by embedding and doping the lithium element; and the multilayer composite film is a carbon film layer and a doped composite film layer composed of the carbon film layer and other elemental components. The doped multi-layer core-shell silicon-based composite material provided by the present invention has a high capacity, good rate performance, high coulombic efficiency, good cycle performance, a low expansion rate, and other electrochemical characteristics when the material is used for the negative electrode of lithium ion battery.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries, in particular to a doped multilayer core-shell silicon-based composite material for lithium-ion batteries and a preparation method thereof. Background technique [0002] As one of the most promising energy storage devices at present, lithium-ion batteries have attracted much attention due to their high voltage, low self-discharge rate, no memory effect, light weight, and small size, and are widely used in portable electronic products. and electric vehicles. With the improvement of living standards and continuous advancement of technology, people have put forward higher requirements for the performance of lithium-ion batteries in many aspects, such as capacity, energy density, rate performance and cycle life. [0003] At present, the most mature graphite anode material has a limited theoretical capacity (372mAh / g) and the actual capacity has been almost fully developed, which limits the furth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/366H01M4/386H01M4/625H01M4/628H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 查道松罗姝汪芳李喆王岑
Owner BERZELIUS (NANJING) CO LTD
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