We have studied the electronic structure of Li<inf>1+</inf><inf>x</inf>[Mn<inf>0.5</inf>Ni<inf>0.5</inf>]<inf>1-</inf><inf>x</inf>O<inf>2</inf> (x = 0.00 and 0.05), one of the promising cathode materials for Li ion battery, by means of x-ray photoemission and absorption spectroscopy. The results show that the valences of Mn and Ni are basically 4+ and 2+, respectively. However, the Mn<sup>3+</sup> component in the x = 0.00 sample gradually increases with the bulk sensitivity of the experiment, indicating that the Jahn-Teller active Mn<sup>3+</sup> ions are introduced in the bulk due to the site exchange between Li and Ni. The Mn<sup>3+</sup> component gets negligibly small in the x = 0.05 sample, which indicates that the excess Li suppresses the site exchange and removes the Jahn-Teller active Mn<sup>3+</sup>.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)