A rapid heat pressing strategy to prepare fluffy reduced graphene oxide films with meso/macropores for high-performance supercapacitors

Abstract

Among the various graphene-based macroscopic architectures, paper-like graphene films exhibit outstanding superiority such as high power output, good malleability and scale-up production. However, the two dimensional graphene nanosheets can easily restack to form dense lamellar microstructures especially in paper-like film, which lose most of the accessible surface and fade the performance of films. In this study, a simple yet high efficient heat pressing method is successfully developed to prepare reduced graphene oxide (RGO) nanosheets with crumpled topography, which can weaken the π-π and van der Waals interactions between nanosheets and inhibit the restacking of nanosheets. Therefore, the resultant RGO film exhibits fluffy layered and meso/macroporous structure (this RGO film is named as f-RGOF). Additionally, the chemical reduction combined with iodine doping reaction endow f-RGOFs with high conductivity of 3000–3300 S m−1. Electrochemical studies demonstrate that the f-RGOF exhibits a high gravimetric capacitance (CM) of 238.4 F g−1 at current density of 0.5 A g−1, and ∼67% retention (158.8 F g−1) with a small IR drop (0.16 V) even up to 80 A g−1. Moreover, the electrochemical performance of f-RGOFs only shows a slight decay (85% CM retention and almost no decay for rate capability) with the increase of areal mass loading, indicating the high utilization rate of electrode material. For practical applications, the flexible solid-state supercapacitors (FSSCs) based on f-RGOFs are also fabricated, which exhibit comparable volumetric energy density of 1.7 mW h cm−3 to 4 V/500 µA h Li thin-film batteries as well as excellent mechanical flexibility. These results demonstrate that the strategy can be potentially applied for fabricating restacking-inhibited and high-performance RGO films using in flexible electronic devices.