Three-dimensional, sulfur-incorporated graphene aerogels for the enhanced performances of pseudocapacitive electrodes

We report the incorporation of sulfur (S)-containing groups into the reduced graphene oxide (RGO) architectures for high performance supercapacitor (SC) electrodes. The S-incorporated RGO aerogel (SRGA) have three-dimensional (3D) internetworked morphology, thereby improving the accessibility to storage sites and ion diffusion. The morphology and chemical structure of the SRGA are comprehensively investigated by spectroscopic methods. The SC electrodes show excellent electrochemical properties such as high specific capacitance of 445.6 F g^-1 at scan rate of 5 mV s^-1, good rate capability of 78.2% and cyclic stability of 73.4% over 1500 cycles due to the existence of S-containing groups and 3D macroscopic structure. As a consequence of the pseudocapacitive feature of S-containing groups, these capacitance enhancements become more pronounced in an aqueous electrolyte despite the enlargement of operating window in organic and ionic liquid electrolytes for high energy applications.