Natural Amino Acids: High-Efficiency Intercalants for Graphene Exfoliation

Graphene (G) has shown increased potentials in thermal, electronic, and high-power devices because of its outstanding thermal and electrical properties. However, for the exfoliation of G, still a great challenge lies in high yield and ecofriendliness. In this study, a green amino acid-assisted ball-milling exfoliation (AABME) strategy has been explored to prepare G nanosheets (GNSs) in a large yield (94.5%) and high concentration (32 mg/mL). What is more, our AABME could be applied to exfoliate other 2D materials like hexagonal boron nitride and molybdenum disulfide. The as-exfoliated GNSs could be directly composited with epoxy resin (EP) for fabrication of GNS/EP composites with outstanding thermal and electric performance. Compared to the neat EP, the thermal and electric conductivities of GNS/EP increased by 16-fold (from 0.17 to 2.85 W/mK) and 10 orders (from 7.0 × 10–15 to 4.81 × 10–5 S/cm), respectively.