A fused product including lithium-manganese spinel, which is optionally doped, having a spinel structure AB2O4, where the site A is occupied by lithium and the site B is occupied by manganese, it being possible for the site B to be doped with an element B′ and it being possible for the site A to exert a substoichiometry or a superstoichiometry with respect to the site B, so that the product observes the formula Li(1+x)Mn(2−y)B′yO4, with −0.20≦x≦0.4 and 0≦y≦1, the element B′ being chosen from aluminum, cobalt, nickel, chromium, iron, magnesium, titanium, vanadium, copper, zinc, gallium, calcium, niobium, yttrium, barium, silicon, boron, zirconium and their mixtures.