Effect of reduced graphene oxide on the enhancement of thermoelectric power factor of γ-NaxCo2O4

•Enhanced thermoelectric power factor were achieved by rGO incorporation in γ-NaxCo2O4.•rGO content at 0.02 wt% gave a maximum power factor of 281 μW m−1 K−2 at 859 K.•The incorporation of rGO in thermoelectric materials as potential route for improving the thermoelectric performance. The γ-NaxCo2O4/reduced graphene oxide (rGO) with various rGO contents (x = 0, 0.02, 0.04, 0.06, and 0.08 wt%) were synthesized by the polymerized complex method and sintered by solid state reaction. Temperature dependence of electrical resistivity, the Seebeck coefficient and power factor was investigated in the range of 312–859 K. The lower electrical resistivity of 80 μΩ m was achieved for 0.02 wt%rGO, while high Seebeck coefficient of 155 μV K−1 for 0.08 wt%rGO at 859 K. Maximum power factor of 281 μW m−1 K−2 at 859 K was obtained at rGO content of 0.02 wt% and higher than γ-NaxCo2O4 (98 μW m−1 K−2). Results suggested that rGO incorporation in the γ-NaxCo2O4 significantly enhanced power factor of thermoelectric materials.