Wallace, Robert M.McDonnell, Stephen2012-10-302013-11-012012-09-131754-5692http://hdl.handle.net/10735.1/2336Many researchers have used nitrogen (N) as a dopant and/or N-containing functional groups to enhance the capacitance of carbon electrodes of electrical double layer (EDL) capacitors. However, the physical mechanism(s) giving rise to the interfacial capacitance of the N-containing carbon electrodes is not well understood. Here, we show that the area-normalized capacitance of lightly N-doped activated graphene with similar porous structure increased from 6 μF cm -2 to 22 μF cm -2 with 0 at%, and 2.3 at% N-doping, respectively. The quantum capacitance of pristine single layer graphene and various N-doped graphene was measured and a trend of upwards shifts of the Dirac Point with increasing N concentration was observed. The increase in bulk capacitance with increasing N concentration, and the increase of the quantum capacitance in the N-doped monolayer graphene versus pristine monolayer graphene suggests that the increase in the EDL type of capacitance of many, if not all, N-doped carbon electrodes studied to date, is primarily due to the modification of the electronic structure of the graphene by the N dopant. It was further found that the quantum capacitance is closely related to the N dopant concentration and N-doping provides an effective way to increase the density of the states of monolayer graphene.© 2012 The Royal Society of ChemistrySupercapacitorsDirac pointNitrogenGrapheneTextThe Royal Society of ChemistryZhang, L. L., X. Zhao, H. Ji, M. D. Stoller, L. Lai, S. Murali, S. McDonnell, B. Cleveger, R. M. Wallace, and R. S. Ruoff. 2012. "Nitrogen Doping of Graphene and its Effect on Quantum Capacitance, and a New Insight on the Enhanced Capacitance of N-Doped Carbon." Energy and Environmental Science 5 (11): 9618-9625.