Carbon-coated silicon oxide / graphite composite particles, as well as preparation methods and applications of the same

A particle and coating technology, applied in carbon preparation/purification, chemical instruments and methods, graphite, etc., can solve problems such as extending cycle time and durability

Pending Publication Date: 2020-04-10
IMERYS GRAPHITE & CARBON SWITZERLAND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Cycling stability can be improved by controlling the concentration and electrolyte, but it is still not sufficient for silicon-containing graphite electrodes

Method used

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  • Carbon-coated silicon oxide / graphite composite particles, as well as preparation methods and applications of the same
  • Carbon-coated silicon oxide / graphite composite particles, as well as preparation methods and applications of the same
  • Carbon-coated silicon oxide / graphite composite particles, as well as preparation methods and applications of the same

Examples

Experimental program
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preparation example Construction

[0048] The preparation of liquid dispersions can be carried out in suitable mills, for example bead mills or planetary mills. Another possibility is that a slurry needs to be prepared followed by a drying step to remove the solvent / liquid.

[0049] In certain embodiments, the drying step is advantageously performed by spray drying, which may optionally be performed in a spray dryer, spouted bed or fluidized bed reactor. found that spray drying is particularly suitable for obtaining X Composite particles with uniform distribution of nanoparticles on graphite core particles.

[0050] The nano-SiO prepared as above can then be X / Graphite composite particles for non-graphitic carbon coating. In some embodiments, the coating is accomplished by chemical vapor deposition (CVD) of pyrolytic carbon. This pyrolytic carbon deposit passivates the surface and reduces the BET SSA by approximately 30% to 90%.

[0051] In general, the amorphous carbon layer should be thick enough to cov...

Embodiment 1

[0133] Example 1: Nano-SiO X / Preparation of graphite composites

[0134] Silicon oxide nanopowder (SiO X , 99.5% of the first predispersion (predispersion No. 1) having a size of 15-20 nm). Contains water and SiO X Dispersions of nanoparticles can be prepared to have a solids content of 4 to 16%. In the examples described further below, the solids contents were 9.5% and 15%, respectively.

[0135] This dispersion was then treated in a Buhler bead mill MMP1-EX (FDCP) to deagglomerate the nanoparticles in the dispersion.

[0136] The parameters used for this process step are described in Table 3.

[0137] table 3:

[0138] Velocity Dispersion 42% Corresponding to 2.5kg / min bead size 0.3–0.4 mm filter 0.15 mm torque 1000 rpm cooling temperature 20 ℃ applied energy 150 KWh / t estimated processing time 10 minutes (for the volume tested)

[0139] After this treatment, the dispersion weight and solids content wer...

Embodiment 2

[0154] Example 2: Carbon-coated nano-SiO X / Graphite Composite (“Coated Composite A”) Preparation

[0155] Preparation of the first nano-SiO using "Recipe 1" of Table 4 X / graphite composite ("Composite A"). Compound A having a silicon content (based on total ash) of 2.8% by weight was charged into a rotary furnace and subjected to CVD coating with propane gas as the carbon source. The rotary kiln was heated to 1050°C and the compound was then continuously fed into the rotary kiln which was still at a temperature of 1050°C. Propane gas ((C 3 h 8 , 3L / min) and nitrogen as a carrier gas (N 2 , 1 L / min) into the reactor to maintain the pressure in the reactor at about 0-20 mbar above atmospheric pressure. A residence time of approximately 20 minutes was triggered by setting the rotary oven to an inclination of 4° and a rotation speed of 6 rpm. Then, depending on whether a hydrophobic or hydrophilic surface is required, the CVD-coated nano-SiO X / Graphite composite (carbon...

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Abstract

The present disclosure relates to novel particulate composite materials comprising a graphitic core particle associated with SiOx nanoparticles (0.2<=X<=1.8), and coated by a layer of non-graphitic carbon, e.g., pyrolytic carbon deposited by chemical vapor deposition (CVD). Also included are processes for making such particles as well as uses and downstream products for the novel composite material, in particular as an active material in negative electrodes in Li-ion batteries.

Description

technical field [0001] The present disclosure relates to a novel particulate composite material comprising X Nanoparticles (0.2≤X≤1.8) are graphitic core particles associated and coated with a layer of non-graphitic carbon such as pyrolytic carbon deposited by chemical vapor deposition (CVD). Also included are methods for the preparation of such particles as well as the use and downstream products of the new composite material, in particular its use as active material in the negative electrode of Li-ion batteries. Background technique [0002] Silicon (Si) due to its theoretical capacity of 3578mAh / g (based on Li as fully lithiated phase 15 Si 4 ), is one of the next-generation anode materials for lithium-ion batteries (LIBs). When used for mobile energy applications, one of the major drawbacks involves the large volume change during electrochemical lithiation and delithiation, which leads to the cracking of silicon particles and silicon degradation. This in turn leads t...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/485H01M4/587H01M4/62H01M4/02H01M10/0525
CPCH01M4/364H01M4/366H01M4/625H01M2004/021H01M2004/027H01M2220/20B82Y40/00H01M4/0428H01M4/131H01M4/133H01M4/1391H01M4/1393B82Y30/00Y02E60/10H01M4/483H01M4/587H01M10/052C01B32/21C01B32/05C01B33/113C01P2006/40C01P2004/80C01B32/186C01B33/18C01P2002/60C01P2004/52C01P2004/64C01P2006/12C09C3/063H01M4/48H01M10/0525Y10T428/30
Inventor 米夏埃尔·斯帕尔米哈尔·古拉斯达夫梅野滝博之帕斯夸尔·佩雷斯
Owner IMERYS GRAPHITE & CARBON SWITZERLAND
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