Facile and secure synthesis of porous partially fluorinated graphene employing weakly coordinating anion for enhanced high-performance symmetric supercapacitor

In this paper, porous partially fluorinated graphene (PFG) for supercapacitors (SCs) was fabricated by a mild and secure one-pot hydrothermal method utilizing weakly coordinating anion BF₄⁻ as the fluorine source. The hydrolysis rate of sodium fluoroborate was adjusted by controlling the reaction temperature and PFG containing semi-ionic C[sbnd]F bonds was obtained, where the content of semi-ionic C[sbnd]F bonds in PFG can be easily regulated. The final experimental results show that the incorporation of fluorine not only modulates the electrochemical properties of the material, but also creates abundant pores. When assembled in a symmetric supercapacitor, the PFG shows a high specific capacitance of 269.7 F g⁻¹ at 1 A g⁻¹ and a superior rate capability with 89.3% capacitance retained, as the current density is increased from 1 A g⁻¹ even to 20 A g⁻¹. Furthermore, the resultant energy density for PFG is 9.4 Wh kg⁻¹ at a power density of 250.0 W kg⁻¹ (1 A g⁻¹). All these results confirm that as-prepared partially fluorinated graphene is appropriate for the application in SCs and mass production.