Topic: Molecular-Level Understanding and Design of Rechargeable Battery Materials
Speaker: Dr. Rob Messinger, Assistant Professor, Department of Chemical Engineering & CUNY Energy Institute
The City College of New York, CUNY
Host: CHBE Graduate Research Day
Time & Date: Friday, February 16th, 2018 (2:30 – 4:00 pm)
Location: Chemical & Biological Engineering Rm 102
Rechargeable battery materials undergo complex structural, chemical, and electronic changes upon repeated charge and discharge, which degrade performance and cause device failure. Such changes are often poorly understood at a molecular level, in part due to the difficulty in characterizing them. To accelerate the design, discovery, and optimization of new battery materials, researchers must understand—and subsequently control—material properties up from the molecular scale. Novel characterization methods and battery electrode materials for rechargeable lithium-ion and aluminium metal batteries will be presented, with an emphasis on molecular understanding and control.
First, for lithium-ion batteries, novel multi-dimensional nuclear magnetic resonance (NMR) experiments will be presented that establish the through-space sub-nanometer proximities of lithium atoms in distinct molecular-level environments. In the crystalline electrode LiVPO4F, such NMR experiments reveal surprisingly high concentrations of lithium defects, revealing disorder at the scale of defect pairs. Notably, these defects are “invisible” to X-ray diffraction (XRD) and atomic-resolution scanning transmission electron microscopy (STEM) measurements. The results provide a general strategy for characterizing chemical and electronic disorder in lithium-ion battery electrodes. Second, for rechargeable aluminium metal batteries, new cathode materials will be presented that are based on crystalline transition-metal compounds as well as graphitic structures. Characterization of the cathode materials will be discussed emphasizing molecular-scale understanding of the reaction mechanisms via multi-dimensional NMR spectroscopy, XRD, electron microscopy, and electrochemical methods. The results yield insights into the opportunities and challenges for researchers that design cathode materials for rechargeable aluminium metal batteries, an emerging energy storage technology
Robert J. Messinger is an Assistant Professor in the Department of Chemical Engineering at The City College of New York (CCNY) and a core faculty member of the CUNY Energy Institute. He earned a Ph.D. in chemical engineering from the University of California, Santa Barbara (2012). Afterwards, he studied at the CNRS, France, first as a European Union Marie Curie Postdoctoral Fellow in Orléans (2012-2014), and subsequently with the Grenoble Institute of Technology (2014-2015). At CCNY, his research group studies materials for energy or engineering applications, with a strategic emphasis on multi-scale understanding and control up from the atomic scale. Current systems of interest include novel materials for rechargeable batteries, as well as multi-phase fluids and polymers for engineering applications. He is an expert in solid-state nuclear magnetic resonance (NMR) spectroscopy. He recently was honored to attend the 65th Lindau Nobel Laureate Conference, with 65 Nobel Laureates and 650 early career researchers in attendance from around the world.