Characterization of aluminum doped lithium-manganese rich composites for higher rate lithium-ion cathodes

Abstract

The effect of synthesis method and aluminum doping on layered lithium-manganese rich, mixed metal oxides is presented. Co-precipitation and sol-gel synthesized lithium-manganese rich composite materials revealed differences in capacity and cycle life, which appears from X-ray photoelectron spectra to be strongly related to the particles' surface reactivity. Small amounts of aluminum doping to the sol-gel material were shown to improve the rate capability and cyclability, in addition to decreasing voltage fade, as shown by differential capacity plots. The electrochemistry of an aluminum doped material was revealed to be highly dependent on the degree of aluminum doping - with the behavior of 1% doped material giving a maximum capacity of 201 mAh g-1 at 150 mAg-1 and a capacity retention of 88% after 200 cycles.