Structural characterization and electrochemical performance of nitrogen doped graphene supercapacitor electrode fabricated by hydrothermal method

Abstract

The introduction of nitrogen (N) into graphene is of great focus as it escalates overall device performance as the introduction of N atoms improves the electronics of the graphene. In this work, the N-doped graphene electrode was prepared by using hydrothermal method where graphene nanoplatelet was used as active material and aqueous ammonia as the nitrogen source. The electrode was then used as the supercapacitor electrode. From Raman analysis, the ID/IG ratio of N-doped graphene has a higher value than that of pristine graphene. This indicates the N-doped graphene possessed more defects and has a higher degree of disorder within the graphene sheet. For X-ray diffraction analysis, the result exhibits a broad peak at 2θ = 26.3o, corresponding to the graphitic profile with an interlayer spacing of 3.57 Å. X-ray photoelectron spectroscopy analysis proved that there is a presence of nitrogen on the graphene surface, with 2.35 % of the atomic concentration. From the cyclic voltammetry, all curves showed an almost rectangular shape at the scan rates of 10 to 100 mVs-1. The calculated specific gravimetric capacitance is 25.2 F g-1 at 10 mV s-1. In addition, charge-discharge analysis confirmed the typical behavior of electric double layer capacitor from the linear symmetric slopes.