Realizing Broad-Range Thermoelectric Performance in PbS through Distorting Rock-Salt Lattice

• • Moderate lattice distortion (entropy ~1.0R) in PbS0.5Se0.35Te0.15 reduces lattice thermal conductivity from 2.41 W m−1 K−1 (PbS) to 0.66 W m−1 K−1 at 300 K, a 73% reduction, enabling efficient phonon scattering without severely compromising carrier mobility. • • Cu interstitial doping (1% Cu) in PbS0.5Se0.35Te0.15 optimizes carrier density and weighted carrier mobility, achieving a room-temperature ZT of 0.53 and a peak ZT of 1.44 at elevated temperatures, demonstrating balanced electrical and thermal transport. • • The engineered material attains a wide-temperature average ZT (ZTave) of 1.08 across 300–773 K, translating to a maximum power generation efficiency (ηmax) of 7.5%, outperforming prior cost-effective PbS-based thermoelectrics. • • The strategy of controlled lattice distortion (entropy ~1.0R) provides a design route for low-cost, earth-abundant thermoelectric materials, achieving performance metrics comparable to high-entropy systems but with less carrier mobility degradation, which is critical for practical waste-heat recovery applications.