Structural studies of materials utilized in lithium battery and fuel cell technology are often hampered by the lack of long-range order found only in well-defined crystalline phases. Powder x-ray diffraction yields only structural parameters that have been averaged over hundreds of lattice sites, and is unable to provide structural information about amorphous compounds. Our laboratory utilizes solid state nuclear magnetic resonance (NMR) methods to investigate structural and chemical aspects of lithium ion cathodes, anodes, electrolytes, interfaces and interphases. NMR is element- (nuclear-) specific and sensitive to small variations in the immediate environment of the ions being probed, for example Li+. NMR is also a powerful tool for probing ion and molecular motion in polymer electrolytes for lithium batteries and fuel cells (both hydrogen and direct methanol), with a dynamic range spanning some nine orders of magnitude through spin-lattice relaxation and self-diffusion measurements. A survey of brief summaries of several recent NMR investigations will be presented, including water and proton transport in nanocomposite PEM fuel cells membranes, single crystal studies of LiMPO4 (M = Fe, Co, Ni) cathodes, SEI formation in lithium ion batteries, charge storage mechanism in carbon/MnO2 nanofoam electrodes, structural aspects of CFx primary lithium battery cathodes, and structural disorder in silicon alloy thermoelectric materials.
Host: Glenn Amatucci