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Dr. Guang Feng

Huazhong University of Science and Technology, China

 

Talk Title
Molecular Insights into Ionic-Liquid-Based Supercapacitors

Talk Abstract
 

The use of electricity generated from renewable but intermittent energy sources, such as solar and wind, requires new concepts for efficient energy storage, so that electrical energy storage devices have become a rising star on the horizon of energy storage technologies. Among them, electrical double layer capacitors (EDLCs), also called supercapacitors, have attracted more and more attention in the energy storage community.

Supercapacitors store electrical energy via ion electrosorption directly at the electrolyte-electrode interface, suggesting that the liquid-solid interfaces play a dominant role in the underlying energy storage mechanism and the resulting device performance. Among electrolytes used in supercapacitors, room-temperature ionic liquids (RTILs) have emerged as promising electrolytes, because of their exceptionally wide electrochemical window, excellent thermal stability, nonvolatility, and relatively inert nature. Despite considerable work on RTIL-based supercapacitors, the details of what would happen at RTIL-electrode interfaces still require in-depth exploration.

During last ten years, we adopted molecular dynamics simulation to study RTIL electrolytes residing at planar, cylindrical, spherical electrode surfaces and inside electrode pores, in comparison with the corresponding experimental measurements, to understand the energy storage mechanism underlying supercapacitors and thus to promote the design of supercapacitors. The contents of this talk would include:

1) Understanding the structural and dynamic nature of bulk RTILs at a molecular level, which would reveal the nano-aggregate, dynamics and ionic mobility, as well as the ion size impact on liquids without confinement.

2) Investigating RTILs-based EDLs at open surfaces (e.g., planar, cylindrical, spherical, with defects, etc.), by integration of molecular modeling and the nano-/microscale experimental techniques (e.g., atomic force microscopy, in situ X-ray reflectivity, and neutron scattering), which would focus on the EDL structure and capacitance as well as the influence from ion size, ion type, applied potential, electrode curvature, etc.

3) Studying supercapacitors consisting of RTILs and nanoporous electrodes, and some of them are compared with small angle X-ray scattering and neutron spin echo, which would embody the pore size effects on capacitance, the ion dynamics under porous confinement, and pore expansion during charging.

4) Exploring the influence of water impurity on RTIL EDLs, which would show for the first work on the adsorption of water on electrode surfaces in contact with humid RTILs and the possible strategy to reduce the water electrosorption at polarized electrodes.

Not restricted to supercapacitors, our work on RTIL-based solid-liquid interfaces would also help to solidify the application of the RTIL into other energy-related areas, such as lithium batteries, solar cells, electrowetting, electrolyte-gated field-effect transistors, electrochemical sensors, etc.

Short Biography

Dr. Guang Feng received his Ph.D. degree in 2010 from Clemson University, USA as the Outstanding Student in the Doctoral Degree Program awardee in Department of Mechanical Engineering. During 2010 to 2014, he worked in Vanderbilt University and The Fluid Interface Reactions, Structures and Transport (FIRST) Energy Frontier Research Center as a postdoctoral research associate and then a research assistant professor. By the end of 2013, he became a professor in State Key Laboratory of Coal Combustion and School of Energy and Power Engineering in Huazhong University of Science and Technology, China after he was awarded by Hubei Provincial 100-Talents Program. He has published 3 book chapters and more than 50 papers in peer-reviewed journals. His current research interests are focused on study of micro-/nano-scale interface and transport phenomena in applications of energy storage, capacitive deionization for desalination and water treatment, shale gas, gas storage, and drug delivery. Right now he serves as an editorial board member of ChemElectroChem. More information about him is available at http://ITP.energy.hust.edu.cn.

 
Talk Keywords
Supercapacitor, electrical double layer, ionic liquid, energy storage mechanism, molecular modeling.
 
Target Audience
Stuents, Academica, Industry
 
Speaker-intro video
TBA 
 

The International Conference on Innovative Applied Energy (IAPE’18)