By using tetrathiafulvalene as reducing and doping agents, three-dimensional （3D） sulfur-doped graphene hydrogels （SGHs） were facilely prepared in mixed solvents of dimethyl formamide and water. Several investigat...By using tetrathiafulvalene as reducing and doping agents, three-dimensional （3D） sulfur-doped graphene hydrogels （SGHs） were facilely prepared in mixed solvents of dimethyl formamide and water. Several investigations reveal that TTF plays a critical role in the formation of such unique 3D architecture, as it not only reduces GO to self-assembly into 3D structures, but also can be transformed to TTF^·＋ and TTF^2＋ as doping agents in the reduction process. The morphology, crystal structure, chemical bonding, elemental composition and porosity of the as-prepared SGHs have been studied. Benefiting from well-defined and cross-linked 3D porous network architectures, the supercapacitors based on the SGHs in KOH 212.5 F·g^-1 at 0.3 A·g^-1. Furthermore, this capacitance also degree of reversibility in the repetitive charge/discharge cycling electrolyte exhibited a high specific capacitance of showed good electrochemical stability and a high test.展开更多
Porous carbons （PC） were prepared from a waste biomass named chestnut shell via a two-step method involving carbonization and KOH activation. The morphology, pore structure and surface chemical properties were inves...Porous carbons （PC） were prepared from a waste biomass named chestnut shell via a two-step method involving carbonization and KOH activation. The morphology, pore structure and surface chemical properties were investigated by scanning electron microscopy （SEM）, N2 sorption, Raman spectroscopy, X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）. The carbons have been evaluated as the electrode materials for supercapacitors by a two-electrode system in 6 mol/L KOH electrolyte. Benefiting from the porous texture, high surface area and high oxygen content, the PCs derived from chestnut shell have exhibited high specific capacitance of 198.2 （PC-l）, 217.2 （PC-2） and 238.2 F·g^-1 （PC-3） at a current density of 0.1 Aog l, good rate capability of 55.7%, 56.6% and 54.9% in a range of 0.1 -20 A·g^-1 and high energy density of 5.6, 6.1 and 6.7 Wh·kg^-1, respectively. This is believed to be due to electric double layer capacitance induced by the abundant micropores and extra pseudo-capacitance generated by oxygen-containing groups. At a power density of 9000 Wh·kg^-1, the energy density is 3.1, 3.5 and 3.7 Whokg 1 for PC-l, PC-2 and PC-3, respectively, demonstrating the potential of the carbons derived from chestnut shells in energy storage devices.展开更多
基金Acknowledgement We are grateful for the financial support from the National Natural Science Foundation of China （Nos. 21402108, 21476132, 51302156, 21576158 and 21576159） and Shandong Natural Science Foundation （No. ZR2014BQ036）.
文摘By using tetrathiafulvalene as reducing and doping agents, three-dimensional （3D） sulfur-doped graphene hydrogels （SGHs） were facilely prepared in mixed solvents of dimethyl formamide and water. Several investigations reveal that TTF plays a critical role in the formation of such unique 3D architecture, as it not only reduces GO to self-assembly into 3D structures, but also can be transformed to TTF^·＋ and TTF^2＋ as doping agents in the reduction process. The morphology, crystal structure, chemical bonding, elemental composition and porosity of the as-prepared SGHs have been studied. Benefiting from well-defined and cross-linked 3D porous network architectures, the supercapacitors based on the SGHs in KOH 212.5 F·g^-1 at 0.3 A·g^-1. Furthermore, this capacitance also degree of reversibility in the repetitive charge/discharge cycling electrolyte exhibited a high specific capacitance of showed good electrochemical stability and a high test.
基金We are grateful for the financial support from the National Natural Science Foundation of China （Nos. 21402108, 21476132, 51302156 and 21576158）, the Natural Science Foundation of Shandong Province （No. ZR2014BQ036） and the Young Teacher Supporting Fund of Shandong University of Technology.
文摘Porous carbons （PC） were prepared from a waste biomass named chestnut shell via a two-step method involving carbonization and KOH activation. The morphology, pore structure and surface chemical properties were investigated by scanning electron microscopy （SEM）, N2 sorption, Raman spectroscopy, X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）. The carbons have been evaluated as the electrode materials for supercapacitors by a two-electrode system in 6 mol/L KOH electrolyte. Benefiting from the porous texture, high surface area and high oxygen content, the PCs derived from chestnut shell have exhibited high specific capacitance of 198.2 （PC-l）, 217.2 （PC-2） and 238.2 F·g^-1 （PC-3） at a current density of 0.1 Aog l, good rate capability of 55.7%, 56.6% and 54.9% in a range of 0.1 -20 A·g^-1 and high energy density of 5.6, 6.1 and 6.7 Wh·kg^-1, respectively. This is believed to be due to electric double layer capacitance induced by the abundant micropores and extra pseudo-capacitance generated by oxygen-containing groups. At a power density of 9000 Wh·kg^-1, the energy density is 3.1, 3.5 and 3.7 Whokg 1 for PC-l, PC-2 and PC-3, respectively, demonstrating the potential of the carbons derived from chestnut shells in energy storage devices.
