Integration of Boron Nitride Into Tin‐Enriched SnSe2 for a High‐performance Thermoelectric Nanocomposite with Optimized Electrical Transport and Mechanical Properties

Abstract Thermoelectric materials with high figures of merit are essential for efficient energy conversion and cooling applications. This study integrates boron nitride (BN) into tin‐enriched SnSe₂ to form a multi‐phase composite with synergistic thermoelectric and mechanical properties. The incorporation of BN into SnSe 2 offers the dual benefit of optimizing both carrier concentration and carrier mobility. Notably, the BN/SnSe 2 composite exhibits a significant increase in the Seebeck coefficient, attributed to an increased bandgap and electronic density of states near the Fermi level, as corroborated by density functional theory calculations. Consequently, an impressive power factor of 940 µWm −1 K −2 is achieved for the sample with a mere 0.8 wt.% BN content. This power factor enhancement, coupled with a notable ≈37% reduction in lattice thermal conductivity due to increased phonon scattering from lattice strain induced by Se vacancies, contributes to a remarkable ZT max value of 0.68 at 767 K, exceeding the performance of pristine SnSe 2 by ≈76%. Additionally, BN enhances stress distribution and deformation behavior, improving stability and reliability under diverse thermal and mechanical conditions. This study demonstrates an effective approach for advancing SnSe₂ thermoelectric materials and provides a foundation for composite design and energy band engineering to achieve high‐performance thermoelectric devices.