Influence of Cobalt Doping on the Thermoelectric Properties of the Magnéli Phase W_<18>O_<49>

The Magnli phase W18O49 exhibits promising thermoelectric properties owing to its high electrical conductivity and low thermal conductivity, despite its low Seebeck coefficient.In this study, (W1-xCox)18O49 (0 x 0.05) was synthesized via a solid-state reaction, followed by spark plasma sintering, to investigate the effect of cobalt dopants on the thermoelectric properties of W18O49.The XRD analysis indicated the formation of W18O49-based phase and the secondary phase CoWO4.The cobalt substitution decreased both the electrical and thermal conductivities while slightly increased the Seebeck coefficient.These reduction in the thermal conductivity led to enhanced thermoelectric performance.The dimensionless figure of merit (ZT) reached to 0.022 at 1073 K for x = 0.05.