Recent Advances in Thermoelectric Materials: Mechanism-Driven Design and Systematic Optimization

Thermoelectric materials realize direct heat–electricity conversion and hold great promise for waste heat recovery.Maximizing the figure of merit ZT requires decoupling the interdependent Seebeck coefficient, electrical conductivity, and thermal conductivity. This review surveys recent advances across conventional inorganic systems (Heusler alloys, skutterudites, Zintl phases, perovskites, chalcogenides, fluorite/antifluorite), two-dimensional layered materials, organic composites, and topological insulators, highlighting that prominent ZT breakthroughs arise from matching effective modulation strategies to specific material systems. Strategies for suppressing lattice thermal conductivity κ L —intrinsic anharmonicity, hierarchical defect engineering, and multiphase heterointerfaces—are analyzed, alongside emerging mechanisms of four-phonon scattering, wavelike phonon tunneling,and machine-learning-accelerated calculations. Power factor optimization via band convergence, flat–dispersive band coexistence, spin–orbit coupling modulation, and device-level modulation doping is reviewed. Current challenges and future directions are outlined, emphasizing the urgency of bridging computational predictions with experimental realization, developing universal physics-informed descriptors, and advancing flexible wide-temperature thermoelectric devices toward practical applications.