Ramos Fernández, Gloria, Canal-Rodríguez, María, Arenillas, Ana, Menéndez, J. Angel, Rodríguez Pastor, Iluminada, Martin-Gullon, Ignacio
Determinant influence of the electrical conductivity versus surface area on the performance of graphene oxide-doped carbon xerogel supercapacitors
Carbon. 2018, 126: 456-463. doi:10.1016/j.carbon.2017.10.025
URI: http://hdl.handle.net/10045/71258
DOI: 10.1016/j.carbon.2017.10.025
ISSN: 0008-6223 (Print)
Abstract: 
A series of resorcinol formaldehyde based carbon xerogels were synthesized under identical conditions using different graphene oxide loads. The gelification reaction was carried out using a stable aqueous suspension of graphene oxide, yielding organic gels with graphene oxide concentrations ranging from 1.2–2.5%. After the carbonization, xerogels with medium surface area (650 m2/g) and a highly improved electrical conductivity were obtained. Specific capacitance of 120 F/g of one electrode at very high scan rate of 500 mV/s were achieved, as well as power densities above 30 kW/kg, which is a significant improvement of 180% with respect to the pristine xerogels. Carbonized xerogels were further steam activated to yield activated carbon xerogels with surface areas of up to 1800 m2/g. The use of activated xerogels improves slightly the specific capacitance at low scan rates only, and there is a sharp decrease above 20 mV/s, resulting in a worse performance than graphene oxide doped carbonized xerogels. The electrical conductivity of the graphene oxide-doped carbon xerogels decreases upon activation, which means that the influence of the electrical conductivity on a carbon xerogel is greater than its specific surface area, which it is the first time it is observed for porous carbons.
Keywords:Electrical conductivity, Surface area, Graphene, Oxide-doped carbon, Xerogel supercapacitors
Elsevier
info:eu-repo/semantics/article