Nanocrystalline TiN derived by a two-step halide approach for electrochemical capacitors

Titanium nitride (TiN) nanocrystallites exhibiting high specific surface area (similar to 128m(2)/g) for electrochemical capacitor application were obtained by a two-step halide approach comprised of a room-temperature TiCl4(1)-NH3(g) reaction followed by heat-treatment under NH3 atmosphere. The synthesized nitride powders were agglomerates containing spherical crystallites similar to 10 nm in diam and exhibit a specific surface area ranging from 128 to 23 m(2)/g depending on the heat-treatment temperature. The specific capacitance evaluated by cyclic voltammetry in 1 M KOH electrolyte ranged from 238 to 24 F/g depending on the heat-treatment temperature and the scan rates employed. Structural characterization was performed using X-ray diffraction, helium pycnometry, N-2 adsorption for specific surface area measurements using the Brunauer-Emmett-Teller method, Fourier transform infrared spectroscopy, and high-resolution transmission electron microscopy. Results of these studies are presented and discussed. (c) 2006 The Electrochemical Society.