Crystallite

Waste heat

Chemistry

Metallurgy

Materials science

Composite material

Thermoelectric effect

Physics

Organic chemistry

Waste heat recovery unit

Tellurium

Raw material

Heat exchanger

Thermal conductivity

Thermoelectric generator

Thermoelectric materials

Thermodynamics

Nature Communications

Low-grade heat accounts for >50% of the total dissipated heat sources in industries. An efficient recovery of low-grade heat into useful electricity not only reduces the consumption of fossil-fuels but also releases the subsequential environmental-crisis. Thermoelectricity offers an ideal solution, yet low-temperature efficient materials have continuously been limited to Bi2Te3-alloys since the discovery in 1950s. Scarcity of tellurium and the strong property anisotropy cause high-cost in both raw-materials and synthesis/processing. Here we demonstrate cheap polycrystalline antimonides for even more efficient thermoelectric waste-heat recovery within 600 K than conventional tellurides. This is enabled by a design of Ni/Fe/Mg3SbBi and Ni/Sb/CdSb contacts for both a prevention of chemical diffusion and a low interfacial resistivity, realizing a record and stable module efficiency at a temperature difference of 270 K. In addition, the raw-material cost to the output power ratio in this work is reduced to be only 1/15 of that of conventional Bi2Te3-modules.

A record thermoelectric efficiency in tellurium-free modules for low-grade waste heat recovery