講者：吳恆良博士
演講題目：Structure and Reactivity at Interfaces: Lithium-Sulfur Batteries 演講時間：10/06（五）15:30~17:20 演講地點：博雅館 103 主持人：廖英志教授 吳恆良助理研究員： 2006 B.S. Chemistry, National Central University, Taiwan. 2008 M.S. Chemistry, National Central University, Taiwan. 2013 Ph.D. Hokkaido University, Japan. 2013-2016, Postdoctoral Fellow, University of Illinois at Urbana-Champaign, USA 2016-Assistant research fellow, Center for Condensed Matter Sciences, National Taiwan University
Structure and Reactivity at Interfaces: Lithium-Sulfur Batteries
Heng-Liang Wu
Center for Condensed Matter Sciences, National Taiwan University
The processes that take place at solid-liquid interfaces significantly affect the performance and reactivity of technological systems including batteries, metal electrodeposition, and enzyme-catalyzed reactions on the supported lipid bilayer. The functionality of the solid-liquid interface plays a crucial role in controlling these systems. In this talk, the effect of structure on the reactivity of interfaces in Lithium-Sulfur (Li-S) battery is mainly discussed. Li–S battery is a promising electrochemical system that has great potential as a higher capacity energy storage device. The theoretical capacity of the S cathode is 1675 mAh g−1 which is much higher than the theoretical capacity of the LiCoO2 cathode (~272 mAh g−1) used in conventional Li-ion batteries. Operation of the Li-S battery involves a series of both solid and solution phase electrochemistry at the interface of the electrode and the electrolyte solution. In situ Raman spectroscopy and electrochemical quartz crystal microbalance (EQCM) are used to understand the mechanism and kinetics of sulfur reduction during Li-S battery operation. Raman results show the formation of various polysulfide species at different state of discharge which are all reversible. EQCM results show that the cathode gains Sauerbrey-mass in the first reduction process and becomes rougher with further discharge. The irreversible changes of the sulfur−carbon cathode is observed during the discharge-charge process. Based on the understanding of sulfur reduction mechanism, the use of a thiol-based electrolyte additive to control the sulfur reduction and oxidation mechanisms and enhance the capacity retention is also discussed using in situ Raman/UV-Vis spectroscopy and mass spectrometry.