Enhanced thermoelectric figure of merit of CoSb3 via large-defect scattering

We have measured the structural, chemical, and transport properties of a series of CoSb3 skutterudite samples modified by fullerene additions of 0, 0.52, 3.28, 3.90, 4.77, and 6.54 mass%. Fullerene is a 60-atom carbon molecule that forms microsize clusters between the grain boundaries of CoSb3. We observed that the dominant scattering mechanism in the electrical transport changes from impurity scattering to grain-boundary scattering near a C-60 content of similar to5-6 mass%, and that thermal conductivity decreases with increasing C-60 content. A significant increase in the thermoelectric figure of merit is achieved for 6.54 mass% C-60 compared to the pure CoSb3. (C) 2004 American Institute of Physics.