Li–Mn–O oxides were synthesized by mechanochemistry from a stoichiometric mixture of Li2O and MnO2 using various grinding times (0<t milling<15h). X-ray diffraction patterns of the ground samples (t milling <10 h ) exhibit the same features as LiMn2O4 spinel structure (SG: Fd3m) with, however, a slight discrepancy in the lattice parameter (a cub) suggesting a non-stoichiometry of the Li–Mn–O oxides. a cub increases with milling time to reach for 8h of grinding a value of 8.24Å similar to stoichiometric LiMn2O4. As a matter of fact, after 8h of milling, mechanosynthesized Li–Mn–O spinel-type oxide shows quasi-identical electrochemical performances as high temperature LiMn2O4 ground for 1h.