Low-temperature eutectic reactive molten salt method for N, S co-doped three-dimensional porous graphene as anode toward high-performance supercapacitors

Abstract

The N, S co-doped three-dimensional porous graphene (N,S-TPG) is prepared in the NaOHNa2CO3 eutectic system (NNES) at a relatively low temperature of 300 °C. The three-dimensional network structure is gained because the NNES medium accelerates the conversion of two-dimensional to three-dimensional architecture, while the abundant pores are obtained by the etching reaction of the NNES as the reactive molten salt. The specific capacitance of N,S-TPG is 535 F g−1. An asymmetric supercapacitor RGO||N,S-TPG is assembled, which shows an energy density of 31.7 Wh kg−1. The capacitance retention of 98 % and coulombic efficiency of ∼100 % are harvested. The excellent electrochemical performance of the RGO||N,S-TPG is attributed to the combination of the construction of the three-dimensional porous structure where the N,S-TPG skeleton provides the conducting channel and the pores serve as ion diffusion channel, as well as the N, S synergistic effect which enhances the hydrophilicity and conductivity of the conducting channel.