The synthesis of Lithiated manganese oxides LixMnO2+delta 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 degreesC and which corresponds to a mixture of a spinel phase (a = 8.16 Angstrom) and a lamellar phase. Galvanostatic cycling tests in the potential window 4.2/2 V show that a stable capacity of 155 mAh/g is achieved after 20 cycles performed at C/20 rate.