Investigations on the nature of electrolyte on the electrochemical supercapacitor performance of heteroatom doped graphene

A rapid facile and one-pot formation of N-doped graphene by benzimidazole as a heterocyclic nitrogen source was explored by supercritical fluid technique. Here, we have investigated the electrochemical capacitance of N-doped graphene using various electrolytes. The availability of nitrogen-containing functionalities was scrutinized by FT-IR spectra. The type and quantity of N-doping were examined via elemental analysis and XPS, separately. Three various weight fractions of graphene oxide and benzimidazole were prepared. The electrochemical capacitance studies illustrated the N-doped graphene bearing 4.4 wt% of N achieved an improved capacitance of 256 F g⁻¹ at 1 A g⁻¹. The capacitive behavior for the full cell using two different aqueous electrolytes was performed and revealed an energy density of 12.3 Wh kg⁻¹ in the aqueous solution of 1 M NaClO₄ which was three times superior to 20% KOH solution (4.1 Wh kg⁻¹) and in further the full cell examination in two different non-aqueous electrolytes, suggesting that the energy density accomplished in EMIMBF₄ electrolyte at 0.2 A g⁻¹ was found to be 30 Wh kg⁻¹ which was superior to 1 M TBABF₄ in acetonitrile (13.8 Wh kg⁻¹).