The effects of La on thermoelectric properties of LaxCo4Sb12 prepared by MA–SPS

Thermoelectric materials formulated with LaxCo4Sb12 were prepared via mechanical alloying (MA) and spark plasma sintering (SPS). The regularities of their thermoelectric properties varying with La content at 100–500 °C are investigated. The experimental results show that the La doping helps achieve the P or N type semiconductor materials and improves their thermoelectric properties. The ZT value increases with La content (x) from 0.1 to 0.9, but decreases when x changes from 0.9 to 2.0. The maximum ZT value is 0.3425 when x = 0.9 at 500 °C and the optimal doped La content is about 0.9–1.0 under the experimental conditions in this study.