Silylene/carbon composite negative electrode material and preparation method thereof

A negative electrode material and carbon composite technology, applied in the direction of battery electrodes, electrical components, circuits, etc., can solve technical problems that have not been completely solved, material specific surface area is too large, silicon simple substance low conductivity, etc., to achieve excellent cycle performance, The effect of high energy density and easy industrial production

Active Publication Date: 2018-08-10
DONGGUAN DONGYANG SOLAR SCI RES & DEV CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the silicon negative electrode has the following problems: 1. There is 300-400% volume expansion during the charge and discharge process, which causes the active material to pulverize and lose electrical contact, and the capacity rapidly decays; 2. During the charge and discharge process, the powder of the material A new surface will be exposed, the SEI film will be formed repeatedly, and a large amount of lithium ions will be consumed, resulting in low charge and discharge efficiency and poor cycle life of the material; 3. The conductivity of silicon is very low
However, the production efficiency of this method is low, and the specific surface area of ​​the material is too large, resulting in a low first effect.
[0007] Therefore, the current technical problems of silicon-carbon composite anode materials have not been completely resolved.

Method used

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  • Silylene/carbon composite negative electrode material and preparation method thereof
  • Silylene/carbon composite negative electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0066] Prepare silicene (D50=1 μm, n=10), SP (D50=30nm), and asphalt powder in a mass ratio of 5:5:90 to prepare a mixed aqueous solution with a solid content of 2%, and carry out ball milling and mixing in a ball mill (ball feed The ratio is 10:1), the rotating speed is 2600r / min, and ball milling is performed for 3 hours to obtain a slurry; the slurry is spray-dried in an air atmosphere, the inlet air temperature is 250°C, and the outlet air temperature is 89°C to obtain silicene / Carbon spherical precursor; transfer the precursor to a tube furnace for carbonization treatment, the atmosphere is nitrogen, the heating rate is 2°C / min, heated to 900°C, kept for 3h, naturally cooled to room temperature, crushed and sieved to obtain silicene / carbon composite anode material.

[0067] After testing, the particle size D50 of the obtained silicene / carbon composite negative electrode material is 19.5 μm, and the specific surface area is 3.61 m 2 / g.

Embodiment 2

[0069] Prepare silicene (D50=0.5 μm, n=5), carbon nanotubes (D50=20nm), and phenolic resin powder in a mass ratio of 5:5:90 to prepare a mixed ethanol solution with a solid content of 5%, and carry out the process in a ball mill Mix by ball milling (the ratio of ball to material is 15:1) at a speed of 1000r / min, and ball mill for 3 hours to obtain a slurry; the slurry is spray-dried under a nitrogen protective atmosphere, the inlet air temperature is 175°C, and the outlet air temperature is 91°C °C to obtain a silicene / carbon spherical precursor; transfer the precursor to a tube furnace for carbonization treatment, the atmosphere is nitrogen, the heating rate is 5 °C / min, heated to 850 °C, kept for 3 hours, naturally cooled to room temperature, broken Sieve to obtain the silicene-carbon composite negative electrode material.

[0070] After testing, the particle size D50 of the obtained silicene / carbon composite negative electrode material is 20.1 μm, and the specific surface a...

Embodiment 3

[0072] Silene (D50=0.1 μm, n=15), acetylene black (D50=50nm), and glucose were prepared into a mixed aqueous solution with a solid content of 3% in a mass ratio of 10:5:85, and ball milled and mixed in a ball mill (ball The material ratio is 10:1), the rotating speed is 1500r / min, ball milling is 1h, and the slurry is obtained; the slurry is spray-dried in the air atmosphere, the inlet air temperature is 200°C, and the outlet air temperature is 95°C, to obtain silicene / Carbon spherical precursor; transfer the precursor to a tube furnace for carbonization treatment, the atmosphere is argon, the heating rate is 2°C / min, heated to 600°C, kept for 3h, naturally cooled to room temperature, crushed and sieved to obtain Sicene / carbon composite anode materials.

[0073] After testing, the particle size D50 of the obtained silicene-carbon composite negative electrode material is 17.3 μm, and the specific surface area is 4.22m 2 / g.

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Abstract

The invention provides a silylene / carbon composite negative electrode material and a preparation method thereof. The composite negative electrode material comprises a spherical amorphous carbon substrate and silylene and conductive particles dispersed in the carbon substrate. The preparation method of the composite negative electrode material comprises the steps of enabling silylene, the conductive particles and a carbon source to be mixed in a solvent to obtain paste; performing spraying drying on the paste to obtain a silylene / carbon spherical precursor; and performing carbonization processing on the precursor in an non-oxidizing atmosphere to obtain the silylene / carbon composite negative electrode material. The silylene / carbon composite negative electrode material provided by the invention is high in energy density, proper in specific surface area, high in initial coulombic efficiency, excellent in cycle performance and rate capability, and relatively high in application prospect.

Description

technical field [0001] The invention relates to the technical field of negative electrode materials for lithium batteries, in particular to a silicene / carbon composite negative electrode material and a preparation method thereof. Background technique [0002] At present, the commercial lithium-ion battery anode material is mainly graphite, and its theoretical specific capacity is only 372mAh / g, which is far from meeting the increasing market demand for high-energy-density lithium-ion batteries. The theoretical capacity of elemental silicon reaches 4200mAh / g, almost 11 times that of graphite, and it has a higher charge and discharge platform, which can avoid the precipitation of elemental lithium on the negative electrode, so it has higher safety performance. However, the silicon negative electrode has the following problems: 1. There is 300-400% volume expansion during the charge and discharge process, which causes the active material to pulverize and lose electrical contact...

Claims

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Application Information

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IPC IPC(8): H01M4/36
CPCH01M4/362Y02E60/10
Inventor 彭果戈朱金保成小康
Owner DONGGUAN DONGYANG SOLAR SCI RES & DEV CO LTD
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