Development of High-Energy and High-Rate Lithium Sulfur Batteries
Department of Energy Engineering，Hanyang University
Abstract: Lithium Sulfur (Li-S) batteries are becoming attractive due to the abundance of elemental sulfur and its environmental compatibility. In addition, sulfur undergoes a two electron redox reaction with lithium and offers an extremely high theoretical specific capacity of 1,675 mAh g-1 and a high energy density of 2,600 Wh kg-1.  Despite these advantages, several issues have hampered the practical use of Li–S batteries. First, the dissolution of lithium polysulfide intermediates in the electrolyte triggers undesirable shuttle reactions.  Second, the insulating character of sulfur (S8) and lithium sulfide (Li2S) impede the full electrochemical utilization of sulfur.  To overcome these drawbacks, several mitigation strategies have been explored by various research groups. In particular, one of best choice is that the use of various carbon and carbon-metal oxides or metal-hydroxides composites materials for maximizing the utilization of sulfur upon cycling. [4,5] In this presentation, I propose a high-energy and high-rate performance Li-S cell, which is designed through the balanced engineering of whole cell component including not only the cathode part but also the separator part. As an excellent polysulfide mediator, a metal oxides or hydroxides greatly improved the reaction kinetics of lithium polysulfide redox reactions in Li-S cell. The modified interlayer or separator that has a highl conductive carbon layer further enhanced the electrochemical performances. As a results, the proposed Li-S cell yields superior rate capability and excellent long-term cycling stability.
Biography: Yang-Kook Sun received his PhD degree from Seoul National University, Korea. He was group leader at Samsung Advanced Institute of Technology and contributed to the commercialization of the lithium polymer battery. He received the “First Prize Award” from the Korea Patent Association due to my contribution on lithium ion battery commercialization at SDI in 1999. After joining Hanyang University in 2000, he has set up one of the largest and the most active battery material research center called ITRC in Korea and probably in the world that is supported by ministry of information and communication republic of Korea. He has received the best professor of the year in college of engineering in 2005 and nominated as distinguished professor at Hanyang University in 2008. His major research interests are design, synthesis and structural analysis of advanced energy storage and conversion materials for application in electrochemical devices, lithium-ion, lithium-sulfur, lithium-air, and sodium-ion batteries. One of his major achievements that allow him to achieve a lot of fame in the battery community is the discovery of a new concept of layered concentration gradient NCM cathode materials for lithium-ion batteries.
He received ETD (Electrochemical Technology Division) Research Award (2007) and Battery Division Research Award (2011) from Electrochemical Society Inc. He has published more than 482 reviewed papers and have 341 patents in the field of batteries and electrochemistry. He has given a large number of plenary and invited talks, chaired sessions, organized various conferences focusing on energy storage. Recently, he also has received several awards including Kyung-Ahm Art & Academy Prize from The Kyung-Ahm Education & Culture Foundation, Highly Cited Researcher from Clarivate Analytics, Battery Division Technology Award from Electrochemical Society Inc.,.
Currently, he contributes a lot to community by serving as a senior editor for ACS Energy Letters from 2016 and before then he served as an editor for the journal of Power Sources.