Exfoliated graphite-ruthenium oxide composite electrodes for electrochemical supercapacitors

The performance of exfoliated graphite (EG)-ruthenium oxide (RuOx)composites as binderless electrodes is evaluated for electrochemical capacitors (ECs). A composite of EG-RuOx is prepared by a modified sol-gel process. The material is characterized using X-ray diffraction and microscopy. Electrochemical capacitors with the composite electrodes in the presence of aqueous sulfuric acid (H2SO4) electrolyte are evaluated using voltammetry, impedance and charge-discharge studies. Cyclic voltammetry reveals very stable current-voltage behaviour up to several thousands of cycles, as well as high specific capacitances, e.g., a few hundreds of farads per grain for the composite that contains 16.5 wt.% RuOx. (C) 2008 Elsevier B.V. All rights reserved.