Structure and electrochemistry of Li xCr yCo 1− yO 2

Abstract

We show that the solid-solution series Li x Cr y Co 1− y O 2 can be prepared as a single phase with x near 1 for 0≤ y≤0.5 and y = 1.0. Using powder X-ray diffraction and Rietveld profile refinement, we show that these solid-solutions are isostructural with LiCoO 2 but with Cr and Co sharing the Co sites. Electrochemical measurements using Li/Li x Cr y Co 1− y O 2 cells show that as y increases the amount of Li which can be reversibly cycled in these materials decreases drastically, thus limiting the practical usefulness of these materials. We were unsuccessful at making single-phase solid-solutions of Li x Cr y Ni 1− y O 2 using similar methods.