Thermoelectric Characterization of (Na1-yMy)1.6Co2O4 (M=K, Ca, Sr)
Thermoelectric Characterization of （Na1-yMy）1.6Co2O4 （M=K, Ca, Sr）

Oxide materials NaCo2O4 and (Na1-yMy)1.6Co2O4 (M=K, 0.05≤y≤0.35; M=Ca, Sr, 0.10≤y≤0.40) were prepared by a sol-gel method. Experimental results indicated that the Seebeck coefficient and the Powerfactor of NaCo2O4 were improved by doping Ca and Sr but not by K. The Power-factor of NaCo2O4 is in its maximum, 1.68×10-4 W·m-1·K-2 and 11% bigger than that of the original one when the dopant fraction of Ca was 0.1. Doping Sr makes NaCo2O4 have the biggest Power-factor, 1.68×10-4 W·m-1·K-2 that is 50% bigger than the non-doping oxide. The experimental results indicate that suitable dopants and addition amounts could improve the thermoelectric properties of NaCo2O4 greatly.