NMR Studies of Gel Electrolytes and Carbon/Lithium Anodes

摘要

The results of our basic research program on spectroscopy of lithium batterymaterials are described in this Final Progress Report. As set forth in the original Collaborative Agreement, some of the work was carried out and published jointly with scientists at the Army Research Lab at Fort Monmouth, NJ. Lithium-7 solid state NMR spectroscopy was utilized to characterize the immediate Li(+) ionic environment in gel electrolytes prepared by immobilizing liquid electrolytes in a polymer matrix such as poly(acrylonitrile) (PAN) or poly(methylmethacrylate) (PMMA). It was concluded that, although the host polymer does affect the microscopic environment and mobility of the Li(+) ions, they are still completely solvated by the liquid solvent molecules in the gel phase. Early in the program the emphasis on C/Li anodes was shifted to Li insertion transition metal oxide cathodes. We have successfully employed solids state NMR techniques to characterize Li local environment and transport properties in these materials, along with companion studies of the host lattice structure by synchrotron x-ray absorption spectroscopies (EXAFS, NEXAFS). Finally, successful minority student recruitment and mentoring efforts are described (this was a Minority Institution Infrastructure Grant).