A powdery compound selected from the group consisting of Li.sub.4Ti.sub.5O.sub.12 and its derivatives selected from the group consisting of Li.sub.4-xM.sub.xTi.sub.5O.sub.12 and Li.sub.4Ti.sub.5-yN.sub.yO.sub.12 (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 .mu.m and 10-50% volume agglomerated particles having a diameter not greater than 100 .mu.m 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.degree. C. and 600.degree. C.