Na x Cu0.11Mn0.89O2 (x=0.4–0.5) with the Na0.44MnO2 structure was prepared by sol–gel, glycine–nitrate combustion synthesis and solid-state routes. Li0.45−x Cu0.11Mn0.89O2 was prepared by ion exchange from the glycine–nitrate sodium-containing precursor. Rietveld refinement of X-ray diffraction power patterns indicates that Cu substitutes in the Mn3-position. The electrochemical characteristics of Li x Cu0.11Mn0.89O2 are changed by Cu-substitution, resulting in a somewhat lower capacity between fixed voltage limits compared to the unsubstituted material.