Improvement of thermoelectric properties of WO3 ceramics by ZnO addition

► Doping WO3 with ZnO can promote the grain growth and the densification. ► The addition of ZnO into WO3 raises the electrical conductivity by about two orders of magnitude. ► There exists an optimum doping concentration of ZnO in WO3 for obtaining the best power factor. ► The power factor of the sample is at least ten times larger than the data in our last paper. ► The thermoelectric properties of WO3 are greatly enhanced by the addition of ZnO.