The lithium insertion into lithium oxide spinels LiM2O4 (M = Ti, V, Mn) is investigated. All three compounds accommodate one extra Li atom per formula unit, the reaction proceeding via two-phase equilibria. At 120°C the capacity of manganese oxides for Li-insertion is relatively high: 2, 1.5, 1.25 Li/Mn for β-MnO2, LiMn2O4, λ-MnO2, respectively. © 1990.