Enhanced thermoelectric performance of high pressure synthesized Sb-doped Mg2Si

Abstract n -type Mg 2 Si 1- x Sb x compounds were prepared within a short duration by using high pressure synthesis followed by spark plasma sintering. The structural and compositional characterizations indicated highly densified single-phase products with no obvious oxidation or volatilization of Mg. High pressure synthesized samples showed greatly enhanced thermoelectric performance compared with ambient-pressure synthesized ones. For the optimal Mg 2 Si 0.985 Sb 0.015 , the power factor reached 3300 μWm −1 K −2  at 773 K meanwhile the lattice thermal conductivity was suppressed to 1.0 Wm −1 K −1  at temperatures higher than 700 K. As a result, the highest ZT of 0.94 was achieved at 873 K. High pressure synthesis thus provides us an alternative and effective pathway to synthesize magnesium silicide based thermoelectric materials.