Intrinsic Large‐Unit‐Cell Systems for Advanced Thermoelectrics and Thermal Management

Abstract

The urgent demand for efficient thermoelectric conversion and precise heat management technologies drives the search for materials capable of simultaneously optimizing often‐conflicting electronic and thermal transport properties. Intrinsic large‐unit‐cell (LUC) systems, such as high‐entropy alloys, sub‐nanometer clusters, porous frameworks, and amorphous materials, demonstrate hierarchically scaled structural complexity and are classified as “structural complexity‐driven transport‐modulating materials.” Characterized by severe lattice distortions, configurational entropy, nanoconfinement, hierarchical porosity, and inherent disorder, these materials intrinsically restrict phonon transport across multiple scales, enabling ultralow lattice thermal conductivity essential for high thermoelectric performance and thermal insulation. Concurrently, their vast compositional flexibility and complex electronic structures provide unique avenues for enhancing electrical conductivity and Seebeck coefficients via mechanisms like band convergence, resonant levels, and energy filtering. This review critically examines the fundamental mechanisms linking the intricate atomic architectures of LUC systems to their exceptional performance in thermoelectrics and thermal management. Furthermore, it highlights the indispensable role of machine learning in navigating their immense design complexity for accelerated discovery, inverse design, and decoding of intricate structure–property relationships, paving the way for next‐generation thermoelectrics and thermal management.