Scalable and fast fabrication of holey multilayer graphene via microwave and its application in supercapacitors

By virtue of its high specific surface area and low tortuosity for ionic storage and transportation, holey graphene has come to be regarded as a promising material for energy storage devices, such as lithium ion batteries, and supercapacitors. For practical applications, a scalable and green preparation method for holey graphene is required. This work proposes a facile preparation method for holey graphene by simply microwaving pristine graphene in air. Compared with previous scalable methods, this method exhibits much greater efficiency, reducing the preparation time from hours to minutes. The mechanism underlying the microwave irradiation-induced formation of nanosized holes involves the interaction between microwaves, electrons, oxygen in air, and carbon atoms in the defect areas of the graphene. The size, density, and distribution of holes can be controlled by tuning the microwave irradiation time and oxygen concentration. Used as a hybrid conductive agent, the as-prepared holey multilayer graphene increases capacitance retention to 96.25% at high current density (8 A g^-1), and 96.48% in long cycles (1 A g^-1 and 10 000 cycles).