Preparation and transport properties of aqueous sol-gel synthesized NaCo2O4−δ

摘要

We have successfully prepared thermoelectric materials NaCo2O4−δ at lower temperature (700°C) using aqueous sol-gel methods. We find that the electrical resistivity and thermopower of NaCo2O4−δ depend strongly on the sintering temperature and partial pressure of oxygen. The oxygen content of NaCo2O4−δ is found to decrease with increasing sintering temperature. The sample prepared at the combination of 700°C and pure flowing oxygen exhibits the highest value of power factor.