Electrochemical and Structural Properties of <i>x</i>Li₂M‘O₃·(1−<i>x</i>)LiMn_0.5Ni_0.5O₂ Electrodes for Lithium Batteries (M‘ = Ti, Mn, Zr; 0 ≤ <i>x</i> ⩽ 0.3)

Abstract

Electrochemical and structural properties of xLi2M‘O3·(1−x)LiMn0.5Ni0.5O2 electrodes (M‘ = Ti, Mn, Zr; 0 ≤ x ≤ 0.3) for lithium batteries are reported. Powder X-ray diffraction, lattice imaging by transmission electron microscopy, and nuclear magnetic resonance spectroscopy provide evidence that, for M‘ = Ti and Mn, the Li2M‘O3 component is structurally integrated into the LiMn0.5Ni0.5O2 component to yield “composite” structures with domains having short-range order, rather than true solid solutions in which the cations are uniformly distributed within discrete layers. Li2TiO3 and Li2ZrO3 components are electrochemically inactive, whereas electrochemical activity can be induced into the Li2MnO3 component above 4.3 V vs Li0. When cycled in lithium cells, xLi2MnO3·(1−x)LiMn0.5Ni0.5O2 electrodes with x = 0.3 provide capacities in excess of 300 mA·h/g over the range 4.6−1.45 V.