Structural and electrochemical properties of amorphous and crystalline molybdenum oxide aerogels

The structure and chemical differences among amorphous, crystalline and nan ocrystalline molybdenum oxide aerogels were determined using extended X-ray absorption fine structure (EXAFS), Fourier transform infrared (FTIR) analy sis and powder X-ray diffraction (XRD). These different forms of the same n ominal material are produced by heat treatment. The influence of the struct ural differences on electrochemical properties was examined using stepped c yclic voltammetry. The most interesting material was the MoO3 aerogel heate d to 300 degreesC. The material was found to be nanocrystalline; there are no XRD peaks but the EXAFS were virtually identical to orthorhombic MoO3. T he electrochemcial response of the nanocrystalline material contains charac teristics of both the amorphous and crystalline forms, but with better lith ium capacity than either one. (C) 2001 Elsevier Science B.V. All rights res erved.