Graphite Oxide: An Interesting Candidate for Aqueous Supercapacitors

A graphite oxide, obtained on a large scale at low cost as an intermediate in the graphene production, achieves specific capacitances (159 Fg−1 in H2SO4 and 82 Fg−1 in (C2H5)4NBF4 in acetonitrile) that compete with those of activated carbons and largely surpass the values obtained with graphene nanoplatelets. More promising, the high electrode density leads to volumetric capacitances of 177 and 59 F cm−3 in the aqueous and the organic electrolytes, respectively, which are above most data reported for carbons. In the aqueous electrolyte, the graphite oxide stands out on energy density when compared to graphene nanoplatelets and on power capability if compared to an activated carbon commercialized for supercapacitors, whereas in the organic electrolyte, the limited interlayer spacing restricts the mobility of the larger ions into the expanded graphitic structure. This study also illustrates that the specific surface of carbons measured by standard gas adsorption may not be a relevant parameter as it does not always match the electrochemically active area involved in the energy storage.Financial support to T.A.C. from EU 7FP (Project Electrograph- 266391) and MICINN (project MAT 2011-25198) is gratefully acknowledged. Financial support for graphene oxide development was obtained from the Research Council of Norway, through grant No 73146. The authors thank the Instituto Universitario de Investigación en Nanociencia de Aragón-Universidad de Zaragoza for the HRTEM images.Peer reviewe