Comparing the Effect of Oxygen Stoichiometry on the Behavior of Li 2 MnO 3 in Pure Phase and Li-rich Forms

Abstract

This work presents an investigation on the effect of oxygen stoichiometry on the behavior of Li 2 MnO 3 and related cathode materials using a thin film deposition technique. It is shown that pure Li 2 MnO 3 and Li 2 MnO 3 -based Li-rich cathodes behave very differentlywhen prepared under similar oxygen partial pressure. Li-rich cathodes perform the best when deposited at low oxygen partial pressure while Li 2 MnO 3 requiresa moderate partial pressure for optimum capacity. This behavior is attributed to impurity formation in pure Li 2 MnO 3 at low oxygen stoichiometry as well as stabilization of Li 2 MnO 3 by the LiMO 2 (M= Ni,Co,Mn)matrix in the case of the Li-rich cathodes.