摘要
To investigate the relationship between the electronic structure and the power factor of Nax CoO2 （x = 0.3, 0.5 and 1.0）, the first-principles calculation is conducted by using density functional theory and the semi-classical Boltzmann theory. Our results suggest that with the decreasing Na content, a transition from semiconductor to semimetal is observed. Na0.3CoO2 possesses a higher electrical conductivity at 1000 K due to its increased density of states near the Fermi energy level. However, an optimal Seebeck coefficient at 1000 K is obtained in Na0.5CoO2 because of its broadened band gap near the Fermi energy level Consequently, a maximum power factor is realized in Na0.5CoO2. Thus our work provides a complete understanding of the relationship between the electronic structure and the thermoelectric power factor of Nax CoO5.
To investigate the relationship between the electronic structure and the power factor of Nax CoO2 （x = 0.3, 0.5 and 1.0）, the first-principles calculation is conducted by using density functional theory and the semi-classical Boltzmann theory. Our results suggest that with the decreasing Na content, a transition from semiconductor to semimetal is observed. Na0.3CoO2 possesses a higher electrical conductivity at 1000 K due to its increased density of states near the Fermi energy level. However, an optimal Seebeck coefficient at 1000 K is obtained in Na0.5CoO2 because of its broadened band gap near the Fermi energy level Consequently, a maximum power factor is realized in Na0.5CoO2. Thus our work provides a complete understanding of the relationship between the electronic structure and the thermoelectric power factor of Nax CoO5.
基金
Supported by the Science Foundation of Henan University of Technology under Grant No 2015XTCX10
