Electron energy loss spectroscopy of Li2.6-xCo0.4N (x=0.0 and 1.6)

Charge distributions of lithium cobalt nitrides Li2.6Co0.4N and Li1.0Co0.4N were investigated using core-level electron energy loss spectroscopy. The N-K spectra of Li2.6Co0.4N and reference sample Li3N Showed that both lithium and cobalt are monovalent in Li2.6Co0.4N The N-K spectrum of electrochemically lithium-extracted Li1.0Co0.4N indicated that a large amount of holes are introduced into nitrogen 2p orbitals by the lithium extraction and that Li1.0Co0.4N reveals a strongly covalent character. The branching ratio of the Co-L spectrum of Li1.0Co0.4N was almost intermediate between those of typical oxides having high-and low-spin ground states. This is attributed to the mixing of several electron configurations due to the covalency between cobalt and nitrogen. (C) 1997 Elsevier Science Ltd.