Single-step hydrothermal synthesis of reduced graphene oxide (rGO) and Fe2O3/rGO composites for supercapacitor applications

Reduced graphene oxide sheets were prepared by hydrothermal method. IR and XRD data revealed that both reduction and exfoliation occur during hydrothermal process of graphite oxide (GtO) aqueous dispersions. The concentration of GtO dispersion, process duration and alkali conditions e.g. presence of K2CO3 influence quality characteristics of the produced materials as it was emerged by Raman spectroscopy. Hydrothermal process allows in parallel with reduction and exfoliation the intercalation with nanoparticles (NPs). By using FeCl3.6H2O in presence of NaAc as a precursor, a composite of reduced graphene oxide (rGO) intercalated with iron oxide NPs (Fe2O3/rGO) was synthesized. Electrochemical measurements indicated that the sample treated with K2CO3 had the best performance in terms of capacitance. Both rGO and Fe2O3/rGO are materials of particular interest for supercapacitor applications

Recycling of typical supercapacitor materials.

A simple, facile and low-cost method for recycling of supercapacitor materials is proposed. This process aims to recover some fundamental components of a used supercapacitor, namely the electrolyte salt tetraethyl ammonium tetrafluoroborate (TEABF4) dissolved in an aprotic organic solvent such as acetonitrile (ACN), the carbonaceous material (activated charcoal, carbon nanotubes) purified, the current collector (aluminium foil) and the separator (paper) for further utilization. The method includes mechanical shredding of the supercapacitor in order to reduce its size, and separation of aluminium foil and paper from the carbonaceous resources containing TEABF4by sieving. The extraction of TEABF4from the carbonaceous material was based on its solubility in water and subsequent separation through filtering and distillation. A cyclic voltammetry curve of the recycled carbonaceous material revealed supercapacitor behaviour allowing a potential reutilization. Furthermore, as BF4 (-)stemming from TEABF4can be slowly hydrolysed in an aqueous environment, thus releasing F(-)anions, which are hazardous, we went on to their gradual trapping with calcium acetate and conversion to non-hazardous CaF2

Single-step hydrothermal synthesis of reduced graphene oxide (rGO) and Fe2O3/rGO composites for supercapacitor applications

Reduced graphene oxide sheets were prepared by hydrothermal method. IR and XRD data revealed that both reduction and exfoliation occur during hydrothermal process of graphite oxide (GtO) aqueous dispersions. The concentration of GtO dispersion, process duration and alkali conditions e.g. presence of K2CO3 influence quality characteristics of the produced materials as it was emerged by Raman spectroscopy. Hydrothermal process allows in parallel with reduction and exfoliation the intercalation with nanoparticles (NPs). By using FeCl3.6H2O in presence of NaAc as a precursor, a composite of reduced graphene oxide (rGO) intercalated with iron oxide NPs (Fe2O3/rGO) was synthesized. Electrochemical measurements indicated that the sample treated with K2CO3 had the best performance in terms of capacitance. Both rGO and Fe2O3/rGO are materials of particular interest for supercapacitor applications