Sulfur-decorated nanomesh graphene for high-performance supercapacitors

Sulfur-decorated nanomesh graphene (S@G) has been synthesized by a 155 °C heat treatment of a mixture of nanomesh graphene and S. The as-obtained S@G materials keep a high specific surface area, and exhibit obviously enhanced conductivity and hydrophilicity as compared to the pristine graphene. X-ray photoelectron spectroscopy and thermogravimetric analysis indicate that most S atoms in the S@G samples are stably combined with nanomesh graphene via covalent bonds rather than exist as free elemental S. As an electrode material for aqueous supercapacitors, the S@G with a S content of 5 wt% delivers a specific capacitance up to 257 F/g at the current density of 0.25 A/g, which is 23.6% higher than that of the undoped graphene. Our results provide a simple approach to scalable synthesis of S-doped porous carbon materials, which have potential applications in the high-performance capacitive energy storage devices.