Electrospray-deposition of graphene electrodes: a simple technique to build high-performance supercapacitors

Abstract

Here we report an electrostatic spray deposition method to prepare three-dimensional porous graphene electrodes for supercapacitor applications. The symmetric supercapacitor exhibits excellent specific capacitance (366 F g⁻¹ at 1 A g⁻¹ in 6 M KOH) and long cycle life (108% capacitance retention up to 40 000 cycles). Moreover, the energy densities of the organic and aqueous electrolyte based supercapacitors reach 22.9 and 8.1 Wh kg⁻¹ when the power densities are 119.2 and 15.4 kW kg⁻¹, respectively. Compared with the previously reported graphene based supercapacitors, the improved properties could be attributed to the excellent three-dimensional open porous electrode structure, which is favorable for the ion diffusion and electron transport. In addition, this method provides a simple electrode-fabrication route without the involvement of conducting additives and binders. It may find vast applications in thin and miniaturized energy storage scenarios.