High surface area metal nitrides or metal oxynitrides for electrical energy storage

The present invention concerns a process to produce a high surface area niobium oxynitride, tantalum oxynitride, vanadium oxynitride, zirconium oxynitride, titanium oxynitride or molybdenum oxynitride coated substrate for use as an electrical energy storage component in a capacitor or a battery configuration. The process relates to: (a) coating one or both flat etched surfaces of a solid substrate, in the form of a thin sheet, with a solution or a slurry of a metal halide in a liquid volatile carrier to produce a thin surface film; (b) contacting the metal halide surface film-carrier coated substrate of step (a) with oxygen, air, or combinations thereof at a temperature to convert the metal halide to metal oxide, respectively, as a thin film and to remove the liquid volatile carrier; (c) repeating steps (a) and (b) to obtain a desired thickness; (d) heating the metal oxide film coated substrate of step (c) in oxygen, air or combinations thereof to convert at least about 95% of the metal chloride to metal oxide; (e) increasing the temperature of the metal oxide coated substrate to elevated temperatures; (f) contacting the oxide coated substrate produced in step (e) with a nitrogen source selected from excess flowing gaseous ammonia, a mixture of ammonia gas and hydrogen gas, or a mixture of hydrogen gas and nitrogen gas at elevated temperatures to convert about 95% or greater of the oxide coating to the corresponding metal oxynitride on the substrate, which metal oxynitride layer has a high surface area and is electrically conductive; and (g) cooling to ambient temperature and recovering the high surface area metal oxynitride coated substrate produced in step (f).