Method for preparing graphene/silicon carbon composite material by taking microcrystalline graphite as carbon source

A silicon-carbon composite material, microcrystalline graphite technology, applied in active material electrodes, electrical components, electrochemical generators, etc. problems, to achieve the effect of good cycle performance and high current discharge capacity, designable capacity, and improved electrical conductivity

Inactive Publication Date: 2018-05-15
HUNAN UNIV OF TECH
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Problems solved by technology

However, due to the volume expansion of silicon, its structure will be destroyed during the charging and discharging process, the active material will fall off from the current collector, and an

Method used

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Experimental program
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Embodiment 1

[0023] This embodiment provides a method for preparing a graphene / silicon-carbon composite material using microcrystalline graphite as a carbon source.

[0024] S1. Use the Hummer method to prepare a certain concentration of graphene oxide dispersion, adjust the concentration of graphene oxide dispersion to 10mg / ml, and mix 0.5-5μm microcrystalline graphite powder with a purity of 99.1% after acid purification with 10mg / ml mL of graphene oxide dispersion was mixed uniformly at a volume ratio of 1:1 to obtain a mixed solution;

[0025] S2. Add dispersant polyethylene glycol 200 to the mixed solution according to 1wt% of the graphite powder mass, and then perform ultrasonic dispersion treatment to form a suspension, add it to a three-necked flask, and place it on an ultrasonic atomizer for ultrasonic atomization at a frequency of 20000 Hz , the time is 30min, forming mixed mist beads;

[0026] S3. Seal one port of the three-necked flask in step S2 with a rubber stopper, one por...

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Abstract

The invention discloses a method for preparing a graphene/silicon carbon composite material by taking microcrystalline graphite as a carbon source. According to the invention, microcrystalline graphite powder is taken as the carbon source, is mixed with graphene oxide dispersion liquid, primary vapour deposition is carried out on copper foil, a transition layer is formed, a stable and firm adhesion point with certain toughness is provided for silicon deposition, and electrode conductivity is increased. The nano dots and nano wires are distributed on a carbon network transition layer, which hasthe growth guiding effect during a secondary vapour deposition process, and a specific shape is generated. The graphene/silicon carbon composite material is composed of several nano particles, has good mechanical strength and toughness, and can effectively reduce the shedding of an active material due to volume expansion of silicon. The material has the characteristics of large reversible capacity, capacity design , good cycle performance and heavy current discharge capability, and high tap density.

Description

technical field [0001] The invention belongs to the technical field of preparation of composite materials, and more specifically relates to a method for preparing graphene / silicon-carbon composite materials using microcrystalline graphite as a carbon source. Background technique [0002] Due to the advantages of large specific energy, high working voltage, good safety, and low environmental pollution, lithium-ion batteries have broad application prospects in various portable electronic devices, electric vehicles, and new energy storage. Generally speaking, as the main body of lithium-ion battery storage, the negative electrode material realizes the intercalation and extraction of lithium ions during the charging and discharging process, which is the key to improving the specific capacity, cycle performance, charge-discharge and other related performance of lithium-ion batteries. At present, the commercial negative electrode materials are mainly traditional carbon materials b...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/362H01M4/386H01M4/625H01M4/628H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 范才河曾广胜
Owner HUNAN UNIV OF TECH
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