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Hole Defects and Nitrogen Doping in Graphene: Implication for Supercapacitor Applications
journal contribution
posted on 2013-11-13, 00:00 authored by Gaixia Luo, Lizhao Liu, Junfeng Zhang, Guobao Li, Baolin Wang, Jijun ZhaoOne
great challenge for supercapacitor is to achieve high energy
capacity and fast charge/discharge rates simultaneously. Porous graphene
with large surface area is a promising candidate for electrode materials
of supercapacitor. Using first-principles calculations and non-equilibrium
Green’s function technique, we have explored the formation
energies, mechanical properties, diffusion behaviors and electrical
conductance of graphene sheets with various hole defects and/or nitrogen
doping. Interestingly, graphene sheets with pyridinic-like holes (especially
hexagonal holes) can be more easily doped with nitrogen and still
retain the excellent mechanical properties of pristine graphene that
is beneficial for the long cycle life. Porous graphene electrode with
moderate hole diameter of 4.2–10 Å facilitates efficient
access of electrolyte and exhibit excellent rate capability. In addition,
doping with nitrogen as electron donors or proton attractors leads
to charge accumulation and generates higher pseudocapacitance. Transmission
coefficients of N-doped graphene sheets with pyridinic-like holes
are only moderately reduced with regard to that of pristine graphene
and are insensitive to the detailed geometry parameters. Overall,
N-doped graphene with pyridinic-like holes exhibits exciting potentials
for high performance energy storage in supercapacitor devices.