Advancements in thermoelectric materials: optimization strategies for enhancing energy conversion

Abstract

Thermoelectric materials are a highly promising category of energy conversion materials. In this paper, we present a multitude of approaches to enhance the efficacy of these materials. The review begins with an introduction to the fundamental concept of the thermoelectric figure of merit (ZT), a key parameter for assessing the performance of thermoelectric materials, as well as theories of electrical and thermal transport, which lay the groundwork for understanding and improving the performance of thermoelectric materials. Subsequently, this paper delves into several typical optimization strategies, including the enhancement of material performance through low-dimensionalization and quantum confinement effects, with detailed discussions on two-dimensional, one-dimensional, and zero-dimensional materials. The role of point defect engineering in modulating material properties and the significance of nano-composite materials in enhancing thermoelectric performance are also explored. Band engineering, an effective optimization technique, offers multiple possibilities for enhancing thermoelectric performance through the adjustment of carrier effective mass, utilization of resonance states, band degeneracy, band convergence, and bandgap tuning. Additionally, the application of phonon engineering in reducing thermal conductivity and improving thermoelectric conversion efficiency is highlighted. Discussions on special structures such as textures, single crystals, core–shell structures, and porous structures, as well as symmetry control strategies, highlight the importance of microstructural control in optimizing thermal conductivity. Consequently, the review explores the significance of the synergistic effects of different strategies, noting that an integrated application of these strategies can maximize the performance of thermoelectric materials. The use of materials genomics and machine learning in screening highly potential thermoelectric materials is also highlighted. Finally, the paper addresses the challenges and developments related to the stability, scalability, sustainability, and integration of thermoelectric materials with other systems. Overall, this article summarizes a series of optimization strategies for thermoelectric materials, providing valuable references and inspiration for researchers in the field, with the aim of further advancing the science of thermoelectric materials.