Thermoelectric technology generates electricity from waste heat, but one bottleneck for wider use is the performance of thermoelectric materials. Manipulating the configurational entropy of a material by introducing different atomic species can tune phase composition and extend the performance optimization space. We enhanced the figure of merit (zT) value to 1.8 at 900 kelvin in an n-type PbSe-based high-entropy material formed by entropy-driven structural stabilization. The largely distorted lattices in this high-entropy system caused unusual shear strains, which provided strong phonon scattering to largely lower lattice thermal conductivity. The thermoelectric conversion efficiency was 12.3% at temperature difference ΔT = 507 kelvin, for the fabricated segmented module based on this n-type high-entropy material. Our demonstration provides a paradigm to improve thermoelectric performance for high-entropy thermoelectric materials through entropy engineering.

A high conversion efficiency of 11.2% was realized in a low-cost PbS-based segmented thermoelectric module.

Nanostructure engineering has improved the performance of thermoelectric materials, but the deteriorated stability of the materials at high temperatures shortens the service life of thermoelectric modules. Here, we realized a...

Eutectoid CdTe/Cu2Te precipitates and Cu interstitials leading to a superlow lattice thermal conductivity in SnTe.

Thermoelectrics enable direct heat-to-electricity transformation, but their performance has so far been restricted by the closely coupled carrier and phonon transport. Here, we demonstrate that the quantum gaps, a class of planar defects characterized by nano-sized potential wells, can decouple carrier and phonon transport by selectively scattering phonons while allowing carriers to pass effectively. We choose the van der Waals gap in GeTe-based materials as a representative example of the quantum gap to illustrate the decoupling mechanism. The nano-sized potential well of the quantum gap in GeTe-based materials is directly visualized by in situ electron holography. Moreover, a more diffused distribution of quantum gaps results in further reduction of lattice thermal conductivity, which leads to a peak ZT of 2.6 at 673 K and an average ZT of 1.6 (323–723 K) in a GeTe system. The quantum gap can also be engineered into other thermoelectrics, which provides a general method for boosting their thermoelectric performance.

Nanostructure engineering is a key strategy for tailoring properties in the fields of batteries, solar cells, thermoelectrics, and so on. Limited by grain coarsening, however, the nanostructure effect gradually degrades during the materials’ manufacturing and in‐service period. Herein, a strategy of cleavage‐fracture for grain shrinking is developed in a Pb0.98Sb0.02Te sample during sintering, and the grain size remains stable after repeated tests. Moreover, the initial grain boundary is filled by fractured slender grains and enriched by dislocations, evolving into a hierarchical grain‐boundary structure. The lattice thermal conductivity (klat) is greatly reduced to approach the amorphous limit. As a result, a record‐high ZT value of ≈1.9 is obtained at 815 K in the n‐type Pb0.98Sb0.02Te sample and a decent efficiency of 6.7% in thermoelectric device. This strategy for grain shrinking will shed light on the application of nanostructure engineering under high temperature and extreme conditions in other material systems.

Flexible thermoelectric harvesting of omnipresent spatial thermodynamic energy, though promising in low-grade waste heat recovery (<100°C), is still far from industrialization because of its unequivocal cost-ineffectiveness caused by low thermoelectric efficiency and power-cost coupled device topology. Here, we demonstrate unconventional upcycling of low-grade heat via physics-guided rationalized flexible thermoelectrics, without increasing total heat input or tailoring material properties, into electricity with a power-cost ratio (W/US$) enhancement of 25.3% compared to conventional counterparts. The reduced material usage (44%) contributes to device power-cost “decoupling,” leading to geometry-dependent optimal electrical matching for output maximization. This offers an energy consumption reduction (19.3%), electricity savings (0.24 kWh W −1 ), and CO 2 emission reduction (0.17 kg W −1 ) for large-scale industrial production, fundamentally reshaping the R&D route of flexible thermoelectrics for techno-economic sustainable heat harvesting. Our findings highlight a facile yet cost-effective strategy not only for low-grade heat harvesting but also for electronic co-design in heat management/recovery frontiers.

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