Oxide thermoelectrics - materials, junctions and modules: Thermoelectric properties and direct junctions of p- and n-type iron tungstates

Abstract

Thermoelectric materials are able to directly convert heat into electricity, which makes them predestined candidates for the recuperation of waste heat and contributing to a more efficient energy economy. They hold enormous potential for energy generation, since all thermodynamic processes lose a major portion of their energy in the form of waste heat. However, conventional thermoelectric materials are often toxic, scarce and/or expensive, and show limited high temperature stability, which currently limits their relevance for large-scale applications. Recently, oxide thermoelectric materials, composed of abundant elements have attracted increased interest, as they offer a cheaper, environmental-friendly, and high-temperature stable alternative. They are usually discovered and researched individually, and only later combined to a p-n pair in a module, which often leads to complications, like thermal mismatch or reactions. In this work the approach was taken to design a compatible pair of new thermoelectric oxides that preclude complications in advance. This novel approach is demonstrated on a model pair of iron tungstates, which show promising thermoelectric properties and an exceptional band alignment, which could prove to be key properties for future thermoelectrics.