A first-principles theoretical study on the potential thermoelectric properties of MgH2and CaH2

First-principles calculations, Boltzmann transport equations, and a modified Slack's model were used to investigate the Seebeck coefficient S, electrical conductivity σ, and thermal conductivity κ of hydrides MgH2 and CaH2. As a result, a largest zT value around 0.38 and 0.55 at 1000 K could be achieved when carrier concentration n ~ 1.7 × 1021 cm−3 and n ~ 7.4 × 1020 cm−3 in the p-type MgH2 and CaH2, respectively. Higher zT values (>1) could be achieved by reduction of the high thermal conductivity. The results of our study gave a support that hydrides MgH2 and CaH2 could be promising as thermoelectric materials.