Enhanced thermoelectric figure of merit of CoSb_(3) via large-defect scattering

摘要

We have measured the structural, chemical, and transport properties of a series of CoSb_(3) 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 CoSb_(3). 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 ～5-6 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 CoSb_(3).