Episode 11: Introduction of hydrogen produces eco-friendly thermoelectric oxides

Many industrial processes require heat or create it as a by-product. Now, Takayoshi Katase from the Tokyo Institute of Technology has found a way to harness this heat in an eco-friendly way, as he explains in an interview with MRS Bulletin podcaster Laura Leay. One way to harness this heat is to use thermoelectric devices to produce electricity via the Seebeck effect. Conventional thermoelectric materials, however, are composed of heavy metals such as lead and tellurium, which are toxic. To incorporate hydrogen into the structure, and so replace the toxic elements, Katase’s research team used a rapid thermal sintering process where the starting material—which already includes the hydrogen—is sealed inside a tube. Some of the oxygen sites in strontium titanate are then substituted by the hydrogen. “More than expected, the hydrogen substitution reduces thermal conductivity less than half, and also increases electronic conductivity, resulting in the large enhancement of energy conversion efficiency,” Katase says. This work was published in a recent issue of Advanced Functional Materials.