Differentiate the pseudocapacitance and double-layer capacitance contributions for nitrogen-doped reduced graphene oxide in acidic and alkaline electrolytes

► The effects of N-doped groups are more pronounced in acids than in alkaline media. ► Pseudocapacitance from pyridinic-/pyrrolic-N is observed negative to 0.6 V in acids. ► Nitrogen-doped groups contribute higher Cdl in H2SO4 compared to that in KOH. ► N-RGO as anodes in both acidic and alkaline media results in high specific energy.