Preparation of high-quality graphene via electrochemical exfoliation & spark plasma sintering and its applications

In this paper, we report a simple and fast approach for producing high-quality graphene (HQG) by electrochemical exfoliation and spark plasma sintering (SPS). Via a pressureless sintering at 1500 °C for 10 min, the oxygen-containing groups of electrochemically exfoliated graphene can be effectively eliminated and its intrinsic structures and properties are restored. The experimental results show that: 1) the HQG exhibits very low defect density (ID/IG = 0.16), extremely high carbon to oxygen (C/O) ratio of 25.3 and good processability in various solvents; 2) When the HQG is applied to fabricate a free-standing graphene paper (G-paper), its conductivity reaches to as high as 38460 S/m; 3) The G-paper without any binders, which is used as supercapacitor electrodes, delivers a specific capacitance of 129.0 F/g at 1 A/g, and retains 97% capacitance even after 1000 cycles.