A powdery compound selected from the group consisting of Li4Ti5O12 and its derivatives selected from the group consisting of Li4−xMxTi5O12 and Li4Ti5−yNyO12 (x and y between 0 and 0.2, M and N selected from the group consisting of Na, K, Mg, Nb, Al, Ni , Co, Zr, Cr, Mn, Fe, Cu, Zn, Si and Mo), used as active material of an electrode for a lithium storage battery, consists of unitary particles having a diameter not greater than 1 μm and 10-50% volume agglomerated particles having a diameter not greater than 100 μm wherein the agglomerated particles formed by agglomeration of said unitary particles. The method for producing such a compound preferably consists in grinding the synthesized oxide for a duration comprised between 24 hours and 48 hours in a planetary mill and in then performing thermal treatment at a temperature comprised between 450° C. and 600° C.