Recent Advances in Thermoelectric Research of TiSe2: Structure, Modulation Strategies, and Performance Optimization

Abstract

Titanium diselenide (TiSe₂), a representative layered transition metal dichalcogenide (TMD), has emerged as a promising candidate for thermoelectric applications due to its unique structural characteristics, tunable electronic properties, and eco-friendly composition. This review provides a comprehensive overview of the recent research progress on TiSe₂-based thermoelectric materials. First, the fundamental structural features and intrinsic thermoelectric properties of TiSe₂ are summarized, including its layered crystal structure, charge density wave (CDW) transition, and intrinsic transport behaviors. Subsequently, various modulation strategies to enhance its thermoelectric performance are systematically discussed, such as chemical doping or intercalation, strain engineering, defect engineering, and heterostructure construction. The underlying mechanisms of performance enhancement, including band-structure optimization, carrier-concentration regulation, and lattice thermal conductivity reduction, are elaborated. Notably, a recently reported dual-chemical strategy that simultaneously modifies intralayer bonding and interlayer charge dynamics is discussed in detail, as it yields an exceptionally high thermoelectric figure of merit (ZT) of 0.82 in Cu_0.8CrTi₂Se₆. This result underscores the potential of coordinated modulation strategies, although continued exploration of alternative dopant combinations and validation by independent groups remain important for establishing general design principles. Furthermore, the latest advances in TiSe₂-based thermoelectric devices are briefly introduced. Finally, the current challenges and future development directions of TiSe₂ thermoelectric materials are prospected, aiming to provide guidance for the design and optimization of high-performance TiSe₂-based thermoelectric systems.