Patent ID: 8173049

Claim:
A process for making an alkali-metal ion-reversible electrode material comprising the steps of: (a) providing an alkali-based complex oxide of the general formula A a M m Z z O o N n F f wherein: A comprises an alkali metal selected from the group consisting of lithium, sodium, and potassium; M comprises at least one transition metal, and optionally at least one non-transition metal, or mixtures thereof; Z comprises at least one non-metal; O is oxygen; N is nitrogen; and F is fluorine, where Z and O are such that the alkali-based complex oxide is selected from the group consisting of sulfates, phosphates, silicates, oxysulfates, oxyphosphates, oxysilicates and mixtures thereof; where a ≧0.1; m, o, and z >0; and n and f ≧0 and selected to ensure electroneutrality in said alkali-based complex oxide; where said alkali-based complex oxide stabilizes all or part of the transition metal ion of M in its lower oxidation level, not considering 0, and conducts alkali metal ions; and (b) contacting said alkali-based complex oxide with a carbonaceous precursor under conditions of temperature, time and pressure effective to form a conductive carbon coating on said alkali-based complex oxide, said conductive carbon coating being in a non-powdery form, substantially homogeneous and covering all or most of the surface with a thin film of carbon that is optimized to give electronic conductivity in said alkali-based complex oxide, without blocking alkali-ion exchanges at the surface of said alkali-based complex oxide, and without reducing the transition metal of said alkali-based complex oxide to a metallic state, the alkali-based complex oxide having mixed electron and alkali-ion conductivity and alkali-ion-exchange capability for use in a battery.