Event
ChBE Special Seminar: Chunmei Ban
Friday, February 5, 2016
10:00 a.m.-11:00 a.m.
Kay 2 Boardroom (#1111), Jeong H. Kim Engineering Building
Dr. Chunsheng Wang
cswang@umd.edu
Chunmei Ban
Senior Scientist, Center for Chemistry and Nanoscience
National Renewable Energy Lab, Golden, CO.
Surface Modification of Silicon Anodes for Durable and High-Energy Lithium-ion Batteries
Carbonaceous materials are the dominant anode materials for lithium-ion batteries since their launch by Sony in 1991. Despite the significantly higher energy density found in silicon, unstable interface and volumetric changes during lithiation and delithiation have prevented the move to silicon-based anodes. Materials and morphological design have been focused to mitigate the structural instabilities that arise during lithium insertion and removal. This talk will introduce a different approach, surface modification, that have been developed recently to accommodate volume expansion and contract, but also modify the surface of silicon against electrical isolation following pulverization, and improve the electronic and ionic conductivities of silicon anodes during operation and cycling. Besides wet chemistry, atomic layer deposition (ALD) and molecular layer deposition (MLD) methods have been utilized to produce polymeric hybrid inorganic-organic coating covalently bonded to surface of silicon particles. Improved performance, including high rate capability and durable cycling, has been achieved for the ALD/MLD coated electrodes. To further investigate the impact of surface modification on the electrochemical behavior, in-situ characterization and molecular simulation have been used to study the morphological evolution and surface structure during electrochemical reactions. The data from the synthesis and analysis shed light on the importance of surface modification for silicon-based electrodes. The results provide the information for new design of surface coatings for electrode materials with the aims of achieving durable high-energy-density lithium-ion batteries.
About the Speaker
Dr. Chunmei Ban currently is a senior scientist of the Center for Chemistry and Nanoscience at the National Renewable Energy Laboratory (NREL). She graduated from Tianjin University in 2003 with a Bachelor and Master’s Degree in Chemical Engineering and Electrochemistry. She continued her graduate research at State University of New York at Binghamton, supervised by professor M. Stanly Whittingham. She received her PhD degree from Materials Chemistry in 2008 and joined NREL at the same year. She has strong background in electrochemistry and extensive experience in synthesis of electrochemically active materials for energy storage systems. Dr. Ban has worked on materials for lithium ion batteries, lithium-air batteries, organic radical batteries and magnesium-ion batteries. She has participated in DOE-funded projects as a principle investigator on intermetallic anodes and oxide cathodes for next-generation Li-ion batteries. In the projects, ultrathin inorganic-organic coatings with superior conformity and uniformity have for the first time been successfully applied to stabilize the high-energy Li-ion electrodes. Dr. Ban's research interest spans from nanoscale materials synthesis, electrochemical analysis to advanced ex-situ and in-situ characterization with the aims to understanding the structural and morphology evolution and their impact on the electrochemical properties.
