Novel hexagonal WO3 (h-WO3) nanorods have been successfully prepared on a large scale by a simple hydrothermal method by adding Na2SO4. Uniform nanorods with diameters of 100–200 nm and lengths of up to several micrometres are obtained. The morphology evolvement and the growth mechanism were studied carefully with different quantities of Na2SO4. Different experimental parameters can lead to different structures and morphologies of the final products in our experiment. The current understanding of the growth mechanism of these nanostructures potentially provides important information about the structure design and morphology-controlled synthesis of WO3 and other oxides. The electrochemical performances of the as-prepared h-WO3 nanowires as anode materials of Li-ion batteries have also been investigated. These batteries have a discharge capacity of 215 mA h g−1 at the initial cycles and show an extreme capacity retention. The results imply that these h-WO3 nanorods are promising anode materials for Li-ion batteries.

Well-dispersed Fe3O4 nanocrystals were synthesized by a simple hydrothermal method. The as-synthesized products were characterized by field emission scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, x-ray diffraction, vibrating sample magnetometer and vector network analysis. The complex permittivity and permeability of paraffin wax and Fe3O4 with different Fe3O4 volume fractions were measured to increase linearly with the increase in the volume fraction of Fe3O4. The magnetic loss was caused mainly by natural resonance, which is in good agreement with the Kittel equation results. When the matching thickness is 3 mm, the calculated reflection loss reaches a maximum value of −21.2 dB at 8.16 GHz with 30% volume fraction of Fe3O4.

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