Self-ignition route to Ag-doped Na1.7Co2O4 and its thermoelectric properties

Ag-doped Na1.7Co2O4 thermoelectric oxides have been synthesized via a simple self-ignition route, which have different nominal compositions in the formula of Na1.7AgyCo2−yO4 (y = 0, 0.1, 0.2, 0.3, 0.4, 0.5). The ceramic samples showed the property of high-crystallographic orientation. The electrical resistivity and Seebeck coefficient were measured using four silver probes method. Analysis showed that phase composition, thermoelectric performance and density of the Ag-doped Na1.7Co2O4 ceramics were influenced by Ag dopant. In the whole measurement temperature, Na1.7Ag0.2Co1.8O4 performed the best thermoelectric properties. The power factor of the doped oxide reached 687.431 μW m−1 K−1 at 873 K.