Preliminary results on electrochemical and structural properties of the cation deficient oxide Mn2.5O4 system are discussed in terms of its viability as an electrode for rechargeable lithium batteries. Chronopotentiometric measurements show two well-defined steps in the potential range of 3.5 V-2.0 V and 2.0 V-1.5 V, involving faradaic yields of approximate to 0.6 and approximate to 1.0 F mol(-1) respectively. A loss of structural integrity was observed for Li ion contents higher than 0.65 per mol. Galvanostatic cycling experiments were performed in the voltage range 4.0-2.0 V and a specific capacity of 43 mAh g(-1) was obtained after the twentieth cycle.