Apr 10, 2012· Lowcost, highyield production of graphene nanosheets (GNs) is essential for practical applications. We have achieved high yield of edgeselectively carboxylated graphite (ECG) by a simple ball milling of pristine graphite in the presence of dry ice. The resultant ECG is highly dispersable in various solvents to selfexfoliate into single and fewlayer (≤ 5 layers) GNs.