A review on the current research on microwave processing techniques applied to graphene-based supercapacitor electrodes: An emerging approach beyond conventional heating

The various methods for microwave processing of materials exhibit numerous advantages, such as short processing times, high yield, expanded reaction conditions, high reproducibility, and high purity of products. Microwave-assisted synthesis strategies have been widely adopted for the preparation of high-performance graphene-based materials for supercapacitor electrodes. Metal oxides, mixed metal oxides, metal hydroxides, layered double hydroxides, carbon nanotubes and conducting polymers are some of the main materials which have been added to graphene derivatives for advanced composite/hybrid electrodes. This review article first provides a brief introduction and an overview of microwave heating and its advantages for processing graphene-based electrode materials. After that, a systematic survey of recently published research on microwave irradiation-assisted processing is presented, focusing on: (i) transformation of graphite/ graphite oxide into graphene/graphene oxide by exfoliation and reduction; (ii) formation of graphene derivatives in various liquid and gaseous media; (iii) modification of graphene derivatives with various metal oxides/hydroxides, carbon nanotubes, and conducting polymers for use in supercapacitors. Major challenges and future perspectives for microwave-assisted processing of graphene-based materials for cutting-edge supercapacitor electrode applications are also summarized in the conclusion.