Enhanced thermoelectric performance in Mg and Ca substituted CdO ceramics

We report a more than 50% enhancement in the thermoelectric figure of merit ZT of CdO ceramics via simultaneous substituting with Mg and Ca. The Mg and Ca substitution is found to greatly suppress both the electrical and the lattice thermal conductivities of CdO while maintaining a moderate power factor. Detailed mechanisms are proposed to explain the experimental results. A ZT value of 0.5 at about 1000 K has been achieved in the optimum substituted sample, which is the highest ZT ever reported among the n-type oxide thermoelectric materials in this temperature range.