{"title":"Biased dual-exfoliation technique with expanded graphite for high-quality few-layer graphene sheets in electrochemical exfoliation","authors":"Sungmook Lim, Niranjanmurthi Lingappan, Wonoh Lee","doi":"10.1007/s42823-025-00865-y","DOIUrl":null,"url":null,"abstract":"<div><p>Efforts to mass-produce high-quality graphene sheets are crucial for advancing its practical and industrial applications across various fields. In this study, we present an innovative electrochemical exfoliation method designed to enhance graphene quality and increase yield. Our approach combines two key techniques: expanding the tightly packed graphite interlayer used as the electrode medium and precisely controlling voltage polarity. The dual-exfoliation technique optimizes the use of anions and cations of varying sizes in the electrolyte to facilitate meticulous intercalation, allowing ions to penetrate deeply and evenly into the graphite interlayer. The newly designed dual-exfoliation technique using biased switching polarity minimizes the generation of oxygen-containing radicals, while the incorporation of expanded graphite accelerates exfoliation speed and reduces oxidation, maintaining high graphene purity. With these improvements, we produced 1–3 layer graphene sheets with minimal defects (I<sub><i>D</i></sub><i>/</i>I<sub><i>G</i></sub> ≈ 0.13) and high purity (C/O ratio ≈ 20.51), achieving a yield 3.1 times larger than previously reported methods. The graphene sheets also demonstrated excellent electrochemical properties in a three-electrode system, with an electrical conductivity of 92.6 S cm<sup>−1</sup>, a specific capacitance of 207.4 F g<sup>−1</sup>, and a retention of 94.8% after 5,000 charge/discharge cycles, highlighting their superior stability and performance.</p><h3>Graphical abstract</h3>\n<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":506,"journal":{"name":"Carbon Letters","volume":"35 3","pages":"1205 - 1220"},"PeriodicalIF":5.5000,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Carbon Letters","FirstCategoryId":"88","ListUrlMain":"https://link.springer.com/article/10.1007/s42823-025-00865-y","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Efforts to mass-produce high-quality graphene sheets are crucial for advancing its practical and industrial applications across various fields. In this study, we present an innovative electrochemical exfoliation method designed to enhance graphene quality and increase yield. Our approach combines two key techniques: expanding the tightly packed graphite interlayer used as the electrode medium and precisely controlling voltage polarity. The dual-exfoliation technique optimizes the use of anions and cations of varying sizes in the electrolyte to facilitate meticulous intercalation, allowing ions to penetrate deeply and evenly into the graphite interlayer. The newly designed dual-exfoliation technique using biased switching polarity minimizes the generation of oxygen-containing radicals, while the incorporation of expanded graphite accelerates exfoliation speed and reduces oxidation, maintaining high graphene purity. With these improvements, we produced 1–3 layer graphene sheets with minimal defects (ID/IG ≈ 0.13) and high purity (C/O ratio ≈ 20.51), achieving a yield 3.1 times larger than previously reported methods. The graphene sheets also demonstrated excellent electrochemical properties in a three-electrode system, with an electrical conductivity of 92.6 S cm−1, a specific capacitance of 207.4 F g−1, and a retention of 94.8% after 5,000 charge/discharge cycles, highlighting their superior stability and performance.
大规模生产高质量石墨烯片的努力对于推进其在各个领域的实际和工业应用至关重要。在这项研究中，我们提出了一种创新的电化学剥离方法，旨在提高石墨烯的质量和产量。我们的方法结合了两个关键技术：扩展作为电极介质的紧密填充石墨中间层和精确控制电压极性。双剥离技术优化了电解质中不同大小的阴离子和阳离子的使用，以促进细致的插层，使离子深入均匀地渗透到石墨中间层中。新设计的双剥离技术使用偏置开关极性，最大限度地减少了含氧自由基的产生，而膨胀石墨的加入加速了剥离速度，减少了氧化，保持了高石墨烯纯度。通过这些改进，我们生产了1-3层石墨烯片，具有最小缺陷（ID/IG≈0.13）和高纯度（C/O比≈20.51），产量是先前报道方法的3.1倍。石墨烯薄膜在三电极体系中也表现出优异的电化学性能，电导率为92.6 S cm−1，比电容为207.4 F g−1,5000次充放电循环后的保留率为94.8%，突出了其优越的稳定性和性能。图形抽象
期刊介绍：
Carbon Letters aims to be a comprehensive journal with complete coverage of carbon materials and carbon-rich molecules. These materials range from, but are not limited to, diamond and graphite through chars, semicokes, mesophase substances, carbon fibers, carbon nanotubes, graphenes, carbon blacks, activated carbons, pyrolytic carbons, glass-like carbons, etc. Papers on the secondary production of new carbon and composite materials from the above mentioned various carbons are within the scope of the journal. Papers on organic substances, including coals, will be considered only if the research has close relation to the resulting carbon materials. Carbon Letters also seeks to keep abreast of new developments in their specialist fields and to unite in finding alternative energy solutions to current issues such as the greenhouse effect and the depletion of the ozone layer. The renewable energy basics, energy storage and conversion, solar energy, wind energy, water energy, nuclear energy, biomass energy, hydrogen production technology, and other clean energy technologies are also within the scope of the journal. Carbon Letters invites original reports of fundamental research in all branches of the theory and practice of carbon science and technology.
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