Orthorhombic LiMnO2 has been prepared in different ways and tested in Li cells. Its structure is transformed, upon Li+ removal, into a spinel-like one. Apart from this transformation, spinel-like materials have also been obtained by leaching LiMnO2 in H2O or by treating it with such molecules as CO2 or aniline. These materials show a more remarkable capacity fading, upon cycling, with respect to untreated LiMnO2. If the latter is prepared in solution, a satisfactory cycling in the 4.4-2.5 V range is observed. In the final stages of the discharge, a lithiated spinel phase is formed, which is characterized by a tetragonal structure with a low c/a ratio.