Protective active nitrides as additives to nonaqueous cathode materials

A process for preparing a stable cathode mass for use in a non-aqueous electrochemical cell having an active metal anode comprising reducing, in-situ, a non-stoichiometric active cathode material having at least two elemental components by means of a conductive reductant from the group of said active metal and a precursor of said active metal to produce, in-situ, a compound of said active metal with the elemental component of said non-stoichiometric active cathode material in excess, stoichiometric cathode active material and, at most 40 percent, based on non-stoichiometric starting material, of chemical species resulting from the reduction of said active cathode material.