Fabrication of N, S co-doped graphene aerogel for high-performance supercapacitors: π-conjugated planar molecules as efficient dopants and pillared agents

Abstract

Rational constructing carbon electrode materials with heteroatoms (eg. N, S, B, F) and high surface area is essencial to the appealing performance of supercapacitor (SC). Here we present a novel fabrication strategy for sandwich-like N, S co-doped three-dimensional (3D) porous graphene aerogels (NSGAs) via one-pot hydrothermal method for high performance SCs materials. The unique advantage of the proposed synthesis strategy is the applications of 2, 5-Dimercapto-1, 3, 4-thiadiazole (DMTD) as bifunctional pillared agents and efficient dopant precursors. The planar DMTD molecules have shown strong supramolecular π-π and H-bonding interactions with graphene oxide (GO), thus avoiding the restacking of graphene sheets and enhancing the doping efficiency and amount of S atoms, which are beneficial to the SC performance of NSGA. The synthesized NSGA samples exhibit the atomic content of S up to 2.39 at.% with surface area at 366.0 m2 g−1, and display a maximum energy density of 10.52 W h kg−1 for assembled symmetric supercapacitor. The relatively high tandem device performance with a remarkable current response, even at 2000 mV s−1, reaches the top level for graphene-based SC system. The proposed simple fabrication strategy and attracting performance of NSGA material shed light on the potential practical applications of graphene-based material as SCs, and the observed structure-function relations also provides physical-chemical insight into the function principle of heteroatom doped graphene in SCs.