Facile and green synthesis of highly conducting graphene paper

A free-standing, highly flexible and conductive graphene paper (GrP) was fabricated via a simple, green, and inexpensive method. The fabrication process starts with electrochemical exfoliation of graphite as partially oxidized graphene suspension, which is then vacuum-filtered and air-dried. The procedure does not warrant any binders, toxic and corrosive agents, or high temperature. The mechanically stable GrP has excellent tensile strength of 52.3 +/- 2.3 MPa at peak elongation of 5.1 +/- 0.4%; ultralow sheet resistance of 2.2 Omega sq(-1), which is highly stable changing by only similar to 4% even after 1000 consecutive bending cycles at 10 mm bending radius; and high electrical conductivity of 3.85 x 10(5) S m(-1). The GrP also possesses high specific capacitance of 195.8 F g(-1) at 1 mV s(-1) in 1 M H2SO4 as electrolyte at room temperature with Pt wire and Ag/AgCl as counter and reference electrodes, respectively. Moreover, the GrP can reusably absorb large amounts of oils and organic solvents. This environmentally friendly GrP fabrication method is of low cost and can be used for large-scale fabrication for applications such as energy-storage devices, flexible/wearable electronics, and removal of oil or toxic organic spills. (C) 2018 Elsevier Ltd. All rights reserved.