Defect-free exfoliation of graphene at ultra-high temperature

We report the effect of treatment at high temperature (2000 degrees C) on the exfoliation of a graphene that had been prepared by amine-treatment of an FeCl3-graphite intercalation compound and by preheat-treatment at low temperature (900 degrees C). A well expanded morphology was produced by the exfoliation, and the expansion did not lead to significant defects in the graphene sp(2) sheet after heating at 2000 degrees C. The exfoliated graphene also exhibited an enhanced capacitance. It should be noted that this heat-treatment method at ultra-high temperature provides a physical procedure for defect-free graphene exfoliation following the electrochemical performance.