Publications Details

In-situ x-ray diffraction of layered LiCoO{sub 2}-Type cathode materials

Rodriguez, M.A.; Ingersoll, David I.; Doughty, Daniel H.

The authors have investigated LiNi{sub 0.8}Co{sub 0.2}O{sub 2} (Sumitomo) and LiNi{sub 5/8}Co{sub 1/4}Mn{sub 1/16}Al{sub 1/16}O{sub 2} (Sandia chemical preparation method) cathode powders via in-situ X-ray Diffraction and Cyclic Voltammetry using a coffee-bag type electrochemical cell. Both cathode materials did not show a monoclinic distortion during de-intercalation but sustained the hexagonal structure up to 4.3 V. The doping of Co into the LiNiO{sub 2} structure appears to stabilize this lattice as the hexagonal structure over the full range of charging (up to 4.3 V). The LiNi{sub 5/8}Co{sub 1/4}Mn{sub 1/16}Al{sub 1/16}O{sub 2} cathode material exhibited a 160 mAh/g capacity (to 4.1 V) on its 1{sup st} cycle, while displaying a much smaller volume change (as compared to LiNi{sub 0.8}Co{sub 0.2}O{sub 2}) during de-intercalation. This reduced overall volume change (2.5 vol%) may have important implications for cycle life of this material.