Systematic Comparison of Graphene Materials for Supercapacitor Electrodes

The comparison of the performance of graphene-based supercapacitors is difficult due to the variety of production methods used to prepare the materials. To the best of our knowledge, there has been no systematic investigation into the effect of the graphene production method on the supercapacitor performance. In this work we compare graphene produced via several routes. These include anodic and cathodic electrochemically exfoliated graphene, liquid phase exfoliated graphene, graphene oxide, reduced graphene oxide and graphene nanoribbons. Graphene oxide exhibited the highest capacitance of ~154 F g-1 in 6 M KOH at 0.5 A g-1 attributed to oxygen functional groups giving an additional pseudocapacitance and preventing significant restacking, however, the capacitance retention was poor due to the low conductivity. In comparison, the anodic electrochemically exfoliated graphene exhibited a capacitance of ~44 F g-1 the highest of the ‘pure’ graphene materials, which all exhibited superior capacitance retention, due to their higher conductivity. The cyclability of all the materials, with the exception of reduced graphene oxide (70 %), was found to be greater than 95 % after 10,000 cycles. These results highlight the importance of matching the graphene production method with a specific application, for example graphene oxide and anodic electrochemically exfoliated graphene would be best suited for high energy and power applications, respectively.