Synthesis of the water-processable all-carbon composites of pristine graphene and graphene oxide through a simple one-step co-exfoliation method and application to supercapacitor

In this work, a facile one-step co-exfoliation method has been constructed to prepare the water-processable all-carbon composites (PG/GO) made of pristine graphene (PG) and graphene oxide (GO) using ultrasonic cell disruptor. The microstructure of the PG/GO composites can be conveniently controlled by varying the ultrasonic time and power. The morphology and structure of the PG/GO composites were characterized using UV-visible absorption spectra, atomic force microscopy, scanning electron microscope, and X-ray photoelectron spectroscopy. The application of these PG/GO composites to supercapacitor has been also explored. As a result, the PG/GO composites deliver more excellent electrochemical performance compared with most all-carbon composites reported. The composite synthesized under the optimized experimental condition (PG/GO10:1) exhibits a specific capacitance of 293.6 F g−1 at the scan rate of 10 mV s−1 and 326.3 F g−1 at the current density of 0.5 A g−1, respectively. The cycling stability of these PG/GO composites is quite good. The specific capacitance of PG/GO10:1 increases with increasing the cycle number and even breaks through 126.9% of the initial value after 10,000 cycles at the scan rate of 100 mV s−1.