Distorted thermal properties: Thermoelectric devices can convert waste heat into electricity, providing one path for improving energy efficiency. Jiang et al. leveraged entropy engineering to synthesize a single-phase high-entropy alloy with attractive thermoelectric properties. By increasing the number of elements in the alloy, the resulting disorder helps to stabilize against breakdown into multiple phases. The disordered and distorted crystal lattice suppresses thermal transport while maintaining the electrical properties, which boosts the heat-conversion efficiency of the material. Science , this issue p. 830

High efficiency Bi₂Te₃-based thermoelectric materials and devices with energy conversion efficiencies of up to 6.0% under a temperature gradient of 217 K.

In recent decades, by continuously enhancing the figure of merit ZT of various thermoelectric (TE) materials, solid state TE technology has matured and is on the verge of making an impact in real industrial settings as a promising approach to harvest waste industrial heat and convert it to useful electricity. Nevertheless, actual TE module development has remained stagnant with rather poor efficiencies. This has raised an urgent need to design rational module structures that rely on complex parameter optimization and utilization of efficient integration technologies that minimize energy losses during bonding of various interfaces. Here, we demonstrate a three-dimensional numerical analysis model of a segmented TE power-generating device, which takes into account the temperature-dependent materials' properties and various parasitic losses. The model generates an optimized design with predictive performance to realize maximum conversion efficiency. Combined with the developed bonding schemes and assembly techniques, the segmented modules consisting of Bi₂Te₃-based alloys and CoSb₃-based filled skutterudites were successfully fabricated with a record-high efficiency of up to 12% when operating under a temperature difference of 541 °C. The rational structure design based on the numerical analysis model and the extremely low thermal and electrical losses enable the heat-to-electricity conversion efficiency to reach up to 96.9% of the theoretical efficiency based on the TE materials themselves. These findings highlight the importance of the optimization strategy for TE power generation devices based on the TE materials' intrinsic properties and demonstrate that realistic high temperature TE modules with predictive high efficiency and high power density can be fabricated, which provides a useful guide to achieve a high conversion efficiency in large-scale TE applications.

Combined high performance of self-propagating synthesized materials and topological structures optimization, half-Heusler single-stage module and half-Heusler/Bi ₂ Te ₃ segmented module attained record-high conversion efficiencies of 9.6% and 12.4%.

Although the CoSb₃-based skutterudite thermoelectric devices have been highly expected for wide uses such as waste heat recovery and space power supply, the limited long-term service stability majorly determined by the degradation of electrode interface obstructs its applications. Here, we built up an effective criterion for screening barrier layer based on the combination of negative interfacial reaction energy and high activation energy barrier of Sb migration through the formed interfacial reaction layer. Accordingly, we predicted niobium as a promising barrier layer. The experimental results show the skutterudite/Nb joint has the slowest interfacial reaction layer growth rate and smallest interfacial electrical resistivity. The fabricated 8-pair skutterudite module using Nb as barrier layer achieves a recorded conversion efficiency of 10.2% at hot-side temperature of 872 K and shows excellent stability during long-time aging. This simple criterion provides an effective guidance on screening barrier layer with bonding-blocking-conducting synergetic functions for thermoelectric device integration.