Patent ID: 7901810

Claim:
A method for synthesizing active materials of general formula A a (MO) b M′ c XO 4 wherein X is selected from the group consisting of phosphorous, sulfur, arsenic and combinations thereof, A is an alkali metal or mixture of alkali metals, M is a transition metal or mixture of transition metals at least one of which is not in its highest oxidation state, M′ comprises a metal, 0<b≦1 and 0<a<2, and 0≦c<1 where a, b, and c are selected to maintain the electroneutrality of the compound, the method comprising the steps of combining starting materials to form a mixture, wherein the starting materials comprise a metal compound of formula (MO) b M′ c XO 4 , wherein M and M′ are the same elements as in the formula above for the active material, but wherein at least one of M and M′ has a higher oxidation state than in the above formula for the active material, a source of reducing carbon, and a source of alkali metal A; and heating the mixture at a temperature about greater than 400° C. and for a time sufficient to form a reaction product wherein at least one of M or M′ is reduced in oxidation state without full reduction to elemental state.