Summary of the Special Invited Talk

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Applications of Local Structural Probes to Study Structure and Dynamics in Battery and Fuel Cell Materials in and ex-situ

This talk will focus on our recent work to develop methods to study local structures by NMR spectroscopy. The first part of the talk will describe the development and application of methods that allow electrochemical devices to be probed while they are operating (i.e., in-situ). This allows, for example, the transformations of the various cell components to be followed under realistic conditions without having to disassemble and take apart the cell. To this end, the application of new in and ex-situ Nuclear Magnetic Resonance (NMR), magnetic resonance imaging (MRI), pulse-field gradient (PFG), and X-ray diffraction approaches to correlate structure and dynamics with function in lithium- and sodium-ion batteries will be described. The in-situ approach allows processes to be captured, which are very difficult to detect directly by ex-situ methods. For example, we can detect processes that occur during extremely fast charging and discharging and structures that would not survive dissassembly of the cell. Complementary ex-situ NMR investigations, and total scattering studies, allow more detailed structural studies to be performed, to correlate local and long-range structure with performance. As an illustration of the approach, I will describe our recent work on sodium and lithium anode materials such as hard carbons, silicon and tin, these materials exhibiting considerable structural disorder, either as synthesized, or during cycling. In the second part of the talk I will describe recent applications of NMR to investigate paramagnetic electrodes. Examples include the use of 17O NMR spectroscopy to examine structure and dynamics in solid oxide fuel cell materials such as La2NiO4+δ and battery materials related to Li2MnO3.

 

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