The synthesis of lithiated manganese oxides Li x MnO2+δ obtained via a sol–gel process combined with an ion-exchange reaction is reported. The electrochemical performances are strongly dependent on the heat-treatment of the Li-exchanged compound obtained after the ion-exchange procedure. The best results are obtained for the sample heat-treated at 300°C and which corresponds to a mixture of a spinel phase (a=8.16Å) and a lamellar phase. Galvanostatic cycling tests in the potential window 4.2/2V show that a stable capacity of 155mAh/g is achieved after 20 cycles performed at C/20 rate.