The Study of Solvothermal Synthesis of Nano-Engineered CoSb3 Skutterudite Thermoelectric Materials

摘要

Nanostructured materials have been shown to enhance phonon scattering and improve the figure of merit of thermoelectric materials. Solvothermal syntheses of nano-engineered CoSb_3 skutterudite have been studied in the present work in which CoCl_2 and SbCl_3 were used as precursors and NaBH_4 as a reductant. Elemental, structural and morphology characterization techniques including: XRD, SEM, TEM and EDAX were used to identify and characterize the products. NaBH_4 was found to be a necessary factor in forming cobalt antimonide. It was detected the products' phase transited from Sb_2Co to CoSb_3 in conjunction with the amount increase of NaBH_4. The change of synthesis time and temperature contributed little on the products' phases under the present experimental routes. Single-phased CoSb_3 skutterudites was obtained from the Solvothermal syntheses combined with an acid wash. The as-prepared CoSb_3 powders consist of irregular nanoparticles with 15～20 nm in size. A possible chemical mechanism was also discussed.