Properties of metallic NaxCo2O4 thermoelectric materials

Abstract

AbstractSince the quite favorable thermoelectric properties of transition-metal oxide NaCo2O4 were first reported by Terasaki in 1997, extensive research work has been conducted, including the efforts to improve TE properties through doping or new synthesis approaches. In addition, theoretical investigations about the enhanced thermopower coupled with the small resistivity values for the metallic NaxCo2O4 have been investigated. The advent of the large thermopower and low resistivity appears not able to be explained via conventional free-electron theory. In this paper, thermoelectric and magnetic properties, including resistivity, thermopower, thermal conductivity, magnetic susceptibility and moment of single crystals and polycrystalline NaxCo2O4 are reported. The effect of Na concentration on the transport properties will also be discussed.