Metal oxide-based negative electrodes have received great attention in recent years mainly for their large lithium insertion capacity. Tin-based amorphous oxides have shown to reversibly intercalate about 600 mAh of lithium per gram of oxide. Unlikely, the use of these materials in practical cells is reduced by the irreversible uptake of lithium that takes place during the first insertion/release cycle. In this paper we show that the irreversible capacity of a non-stoichiometric lithium iron oxide (Li-Fe-O) can be substantially reduced through a preliminary chemical reaction with lithium hydride at high temperature (600 degrees C).