~6Li MAS NMR STUDIES OF CATHODE MATERIALS: SHIFT MECHANISMS IN PARAMAGNETIC MATERIALS AND APPLICATIONS TO LITHIUM MANGANESE OXIDES

摘要

~6Li MAS NMR has been used to study local electronic and atomic structures in a series of potential cathode materials LiMO_2, and LiM_xMn_(2-x) O_4 where M = Fe, Co, Mn, Ni and Cr. Our work has focussed on obtaining a fundamental understanding of the causes of the large (hyperfine) shifts typically observed in the ~6Li MAS NMR spectra of these samples. This knowledge has then been applied to follow changes in electronic structure during the charging and discharging of these materials. Here we focus on the development of an understanding of the shift mechanisms, with specific reference to the spinel materials.