1. Sustainable Energy Technologies

    "Probing Light Elements in Energy Systems Using Neutrons and Ions"

    Presented by Howard Wang, Institute for Material Research and Department of Mechanical Engineering, State University of New York, Binghamton & Materials Measurement Laboratory, National Institute of Standards and Technology

    Wednesday, August 7, 2013, 1:30 pm
    ISB Building 734 2nd Floor Seminar Room 201

    Portable and stationary energy storage is an integral component of the total energy solution. It will play an essential role as alternative, renewable and clean energy sources are increasingly adopted by the society. Some most efficient energy storage technologies rely on the displacement of charged light atoms such as lithium and hydrogen. Rechargeable Li-ion batteries and hydrogen fuel cells, for example, are among the most promising chemical energy storage and conversion technologies. Scientific endeavors in advancing those technologies, however, are often hindered by difficulties of detecting whereabouts and activities of the light ions. In this talk, I will show examples of applying neutron and ion beam techniques to probing the light elements and gaining new insights in the function and failure of energy systems. Real-time neutron depth profiling on Li distribution shows that the discrepancy between the ionic and electric transport is a powerful indicator of the efficiency of the battery operation and the onset of its failure. In situ neutron reflectivity demonstrates effective protective oxide coating on nano-silicon battery electrode undergoing swelling and retraction. Quantitative analysis of in-situ small angle neutron scattering yields the total area of fracture surfaces of graphite particles induced by lithiation/delithiation cycling. Real-time neutron imaging shows highly heterogeneous lithiation pathways. Prompt-gamma neutron activation analysis and forward recoil spectrometry show the efficacy of nanocatalysis and the pathway of hydrogenation in structured metal hydrides. Together, they offer a clearer picture of energy systems containing light elements as the active ingredients.