A comparative study on few-layer graphene production by exfoliation of different starting materials in a low boiling point solvent

• Published in: FlatChem Vol. 1; pp. 74 - 88
• Main Authors: Çelik, Yasemin, Flahaut, Emmanuel, Suvacı, Ender
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2017; Elsevier (Amsterdam, Nederland) [2017-....]
• Subjects: Chemical Sciences; Engineering Sciences; Exfoliation; Expanded graphite; Few-layer graphene sheets; Material chemistry; Materials; Nano-graphite; Expanded graphite; Few-layer graphene sheets; Nano-graphite; Exfoliation
• ISSN: 2452-2627; 2452-2627
• DOI: 10.1016/j.flatc.2016.12.002

[Display omitted] •An exfoliation study was performed using different graphite-based materials.•Exfoliation was performed in isopropyl alcohol to facilitate further applications.•High concentration graphene-based dispersions from nano-graphite powder.•Highly conductive, good quality graphene-based materials from expanded graphite. Three different graphite-based powders (expandable graphite and two different nano-graphite powders) were investigated as starting materials for an effective liquid phase exfoliation process in isopropyl alcohol (IPA). The prepared dispersions were analyzed and compared in terms of their graphene concentration, stability, number of graphene layers and quality, as well as the electrical conductivity of the prepared graphene-based materials. Good quality graphene dispersions (ID/IG<0.3) with a relatively high concentration (∼1.1mg/ml) were prepared in IPA within 90min sonication time by utilizing a high specific surface area (∼175m2/g) nano-graphite powder derived from natural graphite. Transmission electron microscope analyses of this sample revealed mostly folded and scrolled few layer graphene (FLG) sheets (<5 layers) entangled each other. The electrical conductivity of the thin film prepared from this dispersion was ∼15 and 86S/m, before and after annealing, respectively. FLG prepared from expanded graphite, obtained by thermal treatment of expandable graphite, exhibited both much higher quality (ID/IG<0.09) and electrical conductivity (∼2104 and 19,200S/m before and after annealing, respectively) when dispersed in IPA for 90min. However, the graphene-based material concentration of the prepared dispersion was relatively low (∼0.06mg/ml).