ABSTRACT
Nanostructures enhance phonon scattering and improve the figure of merit of thermoelectric materials. Nanosized CoSb(3) skutterudite was synthesized by solvothermal methods using CoCl(2) and SbCl(3) as the precursors. A "two-step" model was suggested for the formation of CoSb(3) based on the X-ray diffraction analysis. The first step is the formation of cobalt diantimonide in the earlier stage during the synthesis process. Diantimonide was then combined with antimony atoms to form the skutterudite structured triantimonide, CoSb(3), in the later stage of the synthesis process as the second step. The synthesized CoSb(3) powders consist of irregular particles with sizes of about 20 nm and sheets of about 80 nm.
Subject(s)
Antimony/chemistry , Cobalt/chemistry , Materials Testing , Nanotechnology/methods , Nanotubes/chemistry , Nanotubes/ultrastructure , Hot Temperature , Molecular Conformation , Particle Size , Powders , Solvents/chemistryABSTRACT
A skutterudite-related antimonide, CoFe(3)Sb(12), was prepared with vacuum melting. XRD analysis showed the material contained Sb, FeSb(2), CoSb(2) and CoSb(3) phases. The electrochemical properties of the ball-milled CoFe(3)Sb(12)-10 wt% graphite composite were studied using pure lithium as the reference electrode. A maximal lithium inserting capacity of about 860 mAh/g was obtained in the first cycle. The reversible capacity of the material was about 560 mAh/g in the first cycle and decreased to ca. 320 mAh/g and 250 mAh/g after 10 and 20 cycles respectively. Ex-situ XRD analyses showed that the antimonides in the pristine material were decomposed after the first discharge and that antimony was the active element for lithium to insert into the host material.
