Microwave-assisted hydrothermal synthesis and electrochemical studies of α- and h-MoO3

two modifications of molybdenum trioxide with orthorhombic (α-moo3) and hexagonal (h-moo3) crystal structure have been synthesized by a microwave-assisted hydrothermal method, facilitated by formic acid. characterization by means of x-ray diffraction, scanning electron microscopy, specific surface analysis, and fourier-transform infrared, raman, and uv-vis spectroscopy reveals phase-pure crystalline powder samples of hexagonal h-moo3 microrods and of α-moo3 nanobelt bundles, respectively. the electrochemical properties of the moo3 compounds, studied by cyclic voltammetry and galvanostatic cycling vs. li/li+, strongly depend on the structure and the applied potential range. in the range of 1.5–3.5 v, li+-ions can be reversibly intercalated into the α-moo3 nanobelts. utilizing the material in this way as intercalation cathode material yields an initial discharge capacity of 295 ma h g−1 at 100 ma g−1 and comparably moderate capacity fading of 25% between cycles 20 and 100. extending the potential range to 0.01–3.0 v induces the conversion reaction to mo, which for both modifications yields high initial capacities of around 1500 ma h g−1 but is associated with much stronger capacity fading.