ABSTRACT:We report here on controlled synthesis, characterization and electrochemical properties of different polymorphs of niobium pentoxides grown by CVD of new single-source precursors. Nb2O5 films deposited at different temperatures showed systematic phase evolution from low-temperature tetragonal (TT-Nb2O5, T-Nb2O5) to high temperature monoclinic modifications (HNb2O5). Optimization of the precursor flux and substrate temperature enabled phase-selective growth of Nb2O5 nanorods and films on conductive mesoporous biomorphic carbon matrices (Bio-C). Nb2O5 thin films deposited on monolithic mesoporous biomorphic carbon (Bio-C) scaffolds produced composite materials integrating the high surface area and conductivity of carbonaceous matrix with the intrinsically high capacitance of nanostructured niobium oxide. Hetero-junctions in Nb2O5/BioC composites were found to be beneficial in electrochemical capacitance. Electrochemical characterization of Nb2O5/BioC composites showed that small amounts of Nb2O5 (as low as 5%) in conjunction with Bio-C resulted in a seven-fold increase in the electrode capacitance, from 15 to 104 F g -1 , making these materials ideally suited for electrochemical energy storage applications.