Glycol-Thermal Continuous Flow Synthesis of Graphene Gel.

Hydrothermal treatment of graphene oxide (GO) aqueous dispersion has been extensively applied to create graphene (a.k.a., chemically modified graphene, or reduced GO) hydrogels, which were dried to yield high-density graphene monoliths and powders with promising potential for electrochemical energy storage applications. Here, we demonstrated a glycol-thermal route that allows the preparation of a graphene gel at around 150 °C, which is below the boiling point of ethylene glycol (EG) and thus eliminates the need for a sealed pressurized reaction vessel. As a result, flow synthesis can be achieved by flowing a GO dispersion in EG through a Teflon tube immersed in a preheated oil bath for continuous production of a graphene gel, which, upon drying, shrinks to yield a densified graphene solid.