石墨
石墨烯
剥脱关节
材料科学
电极
电化学
氧化石墨烯纸
电解质
复合材料
石墨烯泡沫
化学工程
纳米技术
化学
工程类
物理化学
作者
Jing Mei,Zhian Qiu,Teng Gao,Qiang Wu,Fenghua Zheng,Juantao Jiang,Kui Liu,Youguo Huang,Hongqiang Wang,Qingyu Li
出处
期刊:Langmuir
[American Chemical Society]
日期:2023-03-16
卷期号:39 (12): 4413-4426
被引量:5
标识
DOI:10.1021/acs.langmuir.3c00046
摘要
Electrochemical exfoliation starting with graphite powder as the raw material for graphene production shows superiority in cost effectiveness over the popular bulk graphite. However, the crucial conductive network inside the graphite powder electrode along with its formation and influence mechanisms remains blank. Here, an adjustable-pressure graphite powder electrode with a sandwich structure was designed for this. Appropriate encapsulation pressure is necessary and conducive to constructing a continuous and stable conductive network, but overloaded encapsulation pressure is detrimental to the exfoliation and graphene quality. With an initial encapsulation pressure (IEP) of 4 kPa, the graphite powders expand rapidly to a final stable expansion pressure of 49 kPa with a final graphene yield of 46.3%, where 84% of the graphene sheets are less than 4 layers with ID/IG values between 0.22 and 1.24. Increasing the IEP to 52 kPa, the expansion pressure increases to 73 kPa, but the graphene yield decreases to 39.3% with a worse graphene quality including higher layers and ID/IG values of 1.68-2.13. In addition, small-size graphite powders are not suitable for the electrochemical exfoliation. With the particle size decreasing from 50 to 325 mesh, the graphene yield decreases almost linearly from 46.3% to 5.5%. Conductive network and electrolyte migration synergize and constrain each other, codetermining the electrochemical exfoliation. Within an encapsulated structure, the electrochemical exfoliation of the graphite powder electrode proceeds from the outside to the inside. The insights revealed here will provide direction for further development of electrochemical exfoliation of graphite powder to produce graphene.
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