Seminar: Electrode Design for High Energy and High Power Densities Supercapacitors
Presented by Dr Kwun Nam Hui, Institute of Applied Physics and Materials Engineering, University of Macau, China
Supercapacitors are advantageous for their high power density (1–10 kWkg-1), fast charge propagation dynamics within seconds, and long cycling life (> 100,000 cycles) compared with batteries. Carbon-based materials are generally used as electrode materials in electrical double-layer capacitors due to their large specific surface area, high electrical conductivity, and low cost. Although high power density and cycling stability have been demonstrated by carbon-based materials, the capacitance and energy density are low because the charges storage mechanism is based on charge separation at the electrode/electrolyte interface. In contrast to electrical double-layer capacitors, pseudocapacitors utilize transition metal oxides/hydroxides materials that store charges via fast and reversible Faradaic reactions at their surface, resulting in higher specific capacitance and energy density but low power density and cycle life. Currently, the biggest obstacle impeding the development of high-performance supercapacitors is the trade-offs between high energy and high power densities considering the origin of different charge storage mechanisms in electric double-layer capacitors and pseudocapacitors.
A rational design of the structure of electrodes has become an appealing strategy in circumventing the trade-offs between energy and power densities. In this talk, the speaker will present his recent work in the development and application of carbon-based and metal oxide-based electrode materials in supercapacitors. Then he will describe how to rationally design a hybrid electrode, consisting of carbon/graphene/metal oxide, to achieve desirable porous structure and huge ion-accessible surface area for rapid electronic and ionic pathways such that high energy density while retaining high power density can be realized in supercapacitors.
Dr Kwun Nam HUI is currently an Assistant Professor at the Institute of Applied Physics and Materials Engineering, University of Macau, Macau SAR, China. Prior to this, he was Associate Professor at Pusan National University, Republic of Korea. His current research focuses on the synthesis of hierarchical carbon/graphene materials as well as on the development of 3D hierarchical layered double hydroxide materials as advanced electrode materials for energy storage and conversion applications. He has published more than 110 journal articles with a citation of over 1800 times and an h-index of 26. He has managed 15 research projects with a total research grant of AUD 1.6 million. His research has led to one US patent, eleven Korea patents, four review papers, three book chapters.