Arc discharge synthesis of graphene with enhanced boron doping concentration for electrochemical applications

The physicochemical properties of graphene, such as the bandgap and electrical conductivity, can be tuned when the carbon atoms are replaced with other heteroatoms. In addition to nitrogen, boron is a dopant that can compensate for the properties lacking in graphene; however, boron-doped graphene has not received significant attention owing to its low doping rate. In this study, we report an improvement in the doping efficiency of arc graphene by utilizing a boron precursor and graphene oxide as anode carbon fillers. X-ray photoelectron spectroscopy revealed that the doping level of the synthesized graphene flakes (5.7at.%) was significantly higher than that of boron-doped arc graphene reported in the literature (3at.%). Cyclic voltammetry, electrochemical impedance spectroscopy, and constant-current charge/discharge experiments were performed to investigate the electrochemical properties of boron-doped graphene. The synthesized boron-doped graphene exhibited an areal capacitance of 66 μF cm⁻², which is superior to that of other doped carbon materials. The electrochemical activity of boron-doped graphene is affected more by functionalized doping than by substitutional doping, because of the improved wettability displayed by the former. Boron-doped graphene flakes required for various applications can be easily obtained by arc discharge synthesis.