Asymmetric Supercapacitors Based on Nanostructured Metal Oixide@Carbon Hybrids
Duy Tho Pham
Sungkyunkwan University (SKKU)
Abstract: Asymmetric supercapacitors employ two different electrode materials with different working potentials and charge-storage mechanisms, e.g. one for redox reaction or pseudocapacitance similar to batteries and one for electric double layer capacitance similar to supercapacitors, to improve both energy density and power density. The choice of materials and control of nanostructures are the keys to enhance the electrochemical performances. The use of aqueous electrolyte is desired for safety issues but the opening operation voltage window remains a challenge. Here, we chose MoO3 and MnO2 for each electrode where both exhibit pseudocapacitance with high voltage window of 2 V. Each metal oxide was further nanostructured with graphene or carbon nanotubes. The metal oxides@carbon hybrid exhibit improved surface area and electrical conductivity compared to the pristine metal oxides. For full cell asymmetric supercapacitors with Na2SO4 electrolyte, high energy and power density, as well as good cycling stability of the devices were obtained. Moreover, the simple self-assembly approach and free-standing nature of these metal oxides@carbon hybrid films bring a great potential for the development of safety, low-cost, and wearable energy storage devices in the near future.
Biography: Duy Tho Pham is working as a post-doctoral researcher in Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Korea. He received his Ph.D degree in material science from Department of Energy Science at Sungkyunkwan University, Korea, in 2015. His research involves the synthesis of nanomaterials, mainly focused on carbon-based materials, and its applications in energy storage.