Solid-state NMR studies of modified LiCoO/sub 2/ as cathodes of lithium rechargeable battery

As a cathode material for commercial lithium rechargeable battery, layered lithium cobalt oxide, LiCoO/sub 2/, is the most attractive cathode material due to its high specific capacity, high operating cell voltage, and excellent recycleability. To understand the local environment by modification of LiCoO/sub 2/, diverse LiCoO/sub 2/ materials, such as Li/sub x/CoO/sub 2/ (x = 1.0, 1.05, and 1.1), and Al-doped and Al/sub 2/O/sub 3/-coated LiCoO/sub 2/, have been studied by solid-state NMR techniques. Herein, observed /sup 7/Li and /sup 27/Al magic angle spinning (MAS) NMR spectra are simulated to determine the quadrupole coupling constant (C/sub Q/) and the asymmetric parameter (/spl eta/) of each atomic sites. The structural states of lithium and aluminum in those samples were successfully identified by them.