D.M. Soares, R. Vicentini, A.C. Peterlevitz, C.B. Rodella, L.M. Da Silva, G. Singh, H. Zanin
Kansas State University,
Keywords: supercapacitors, tungsten carbide, tungsten oxide, HFCVD, CVD, pseudocapacitance
Summary:The pursuit for high capacitance, low cost, and environmentally friend materials for energy storage devices is crucial for more people all over the world to have access to technology and renewable energy sources. Regarding supercapacitors, apart from carbonaceous materials, whose charge storage mechanism relies mostly in electrostatic adsorption in the electrolyte/electrode interface, pseudocapacitive materials occupy unique position, given the fact that higher power density and energy may be achieved due to faradaic or redox reactions. However, usually, pseudocapacitive materials do not present long term cyclability. Here we report one-port synthesis of tungsten carbide (W2C) and tungsten oxide species (WxOy), which presents both faradaic behavior and cyclability. A thorough characterization of the as-synthesized material is presented, which includes synchrotron X-ray diffraction source. Likewise, a detailed electrochemical study was also conducted. Results indicate that, as aqueous-based symmetrical electrochemical capacitors, an improved efficiency with 160% enhancement on the specific capacitance on the 10,000th cycle. Thus, results may enable further developments on pseudocapacitive that allow both higher power and energy densities, as well as cyclability.