High-Performance Thermoelectric Oxides Based on Spinel Structure

High-performance thermoelectric oxides could offer a great energy solution for integrated and embedded applications in sensing and electronics industries. Oxides, however, often suffer from low Seebeck coefficient when compared with other classes of thermoelectric materials. In search of high-performance thermoelectric oxides, we present a comprehensive density functional investigation, based on GGA+U formalism, surveying the 3d and 4d transition-metal-containing ferrites of the spinel structure. Consequently, we predict MnFe2O4 and RhFe2O4 have Seebeck coefficients of ±600 μV K-1 at near room temperature, achieved by light hole and electron doping. Furthermore, CrFe2O4 and MoFe2O4 have even higher ambient Seebeck coefficients at ±700 μV K-1. In the latter compounds, the Seebeck coefficient is approximately a flat function of temperature up to ∼700 K, offering a tremendous operational convenience. Additionally, MoFe2O4 doped with 1019 holes/cm3 has a calculated thermoelectric power factor of 689.81 μW K-2 m-1 at 300 K and 455.67 μW K-2 m-1 at 600 K. The thermoelectric properties predicted here can bring these thermoelectric oxides to applications at lower temperatures traditionally fulfilled by more toxic and otherwise burdensome materials.