Highly Conductive Graphene Paper with Vertically Aligned Reduced Graphene Oxide Sheets Fabricated by Improved Electrospray Deposition Technique

Because of its notable electrical and mechanical properties, the highly conductive graphene paper has great potential applications in future flexible electronics. In this study, we report a simple and effective method to prepare vertically aligned graphene oxide papers from graphene oxide suspensions by an improved electrospray deposition technique with a moving stage, which is controlled by computer. Then, the flexible reduced graphene oxide papers are successfully synthesized after reduction by using hydroiodic acid. The obtained reduced graphene oxide paper has an electrical conductivity as high as 6180 S/m, which is more than one and a half times of the reduced graphene oxide paper film, which was fabricated by using the electrospray deposition technique without the moving stage. The experimental results approved for the first time that the degree of alignment of reduced graphene oxide sheets can affect the conductivity of the reduced graphene oxide papers. Further electrochemical measurements for a symmetrical supercapacitor device based on the prepared reduced graphene oxide paper indicate that it has great capacitive performance and electrochemical stability. It exhibited relatively high specific capacitance (174 F·g^-1) at a current density of 1 A·g^-1 in 6 M KOH aqueous solution, and its capacitance can retain approximately 86% after 1000 cycles. In addition, patterned freestanding reduced graphene oxide papers, which have potential applications in many fields such as stretchable electronics and wearable devices, also can be fabricated by using this method.