A compound containing titanium diphosphate TiP2O7 and carbon covering at least part of the surface of the TiP2O7 particles presents properties which make it suitable for use as active material of an electrode for a lithium storage battery. A compound of this kind is prepared more particularly by mixing at least one first precursor containing the titanium element with a +4 oxidation state, a phosphorus-based second precursor and an organic precursor containing the carbon element. The mixture then undergoes heat treatment at a temperature of between 500° C. and 800° C. in an inert atmosphere.