Development and Applications of Thermoelectric Oxide Ceramics and Devices

Abstract

Thermoelectric materials have gained wide attention to realize multilevel efficient energy management to alleviate the increasingly severe energy crisis. Oxide ceramics were well-explored as potential thermoelectric candidates because of their outstanding merits, including abundance, eco-friendliness, high-temperature stability, and chemical stability. In this work, we aim to provide a comprehensive summary of the diversified state-of-the-art oxide ceramics and establish the links between composition designing, preparation process, structural characteristics, and properties to summarize the underlying chemistry and physics mechanism of band engineering, doping, composited with the second phase, defects engineering, and entropy engineering. Furthermore, advanced device design and applications such as thermoelectric modules, miniature generators, sensors, and coolers were reviewed. Ultimately, the challenges and future perspective of oxides ceramics for the device design and thermoelectric applications in the development of energy harvesting technology have been prospected.

Electrical Property Enhancement in Orientation‐Modulated Perovskite La‐Doped SrTiO3 Thermoelectric Thin Films

“…Annealing oxides in a reducing atmosphere could create oxygen vacancies and electrons, which was widely applied in n-type thermoelectric oxides to tune the carrier concentration. [20,40,45] In metallic conductors, the fully ionized itinerant electrons might not result in valence reduction of cations causing lattice expansion. Then the oxygen vacancies were responsible for the chemical contraction.…”

“…[39,40] However, the carrier grain boundary scattering could severely suppress the carrier mobility of SrTiO 3 -based thermoelectric ceramics. [41][42][43] Interface engineering is an effective way to reduce the scattering by lowering the energy barrier of grain boundaries, [44][45][46][47] and by realizing conduction band alignment to transport electrons and scattering phonons. [48] And in addition, the epitaxial growth of thin films with few grain boundaries could be another strategy.…”

Electronic transport and the thermoelectric properties of donor-doped SrTiO3

“…However, many of these high-zT materials are composed of heavy, toxic, and/or rare elements, and some materials also show poor thermal stability at high temperature, both of which restrict their applications [7][8][9][10]. As a result, there has been increasing focus on oxide-based materials as non-toxic, cheap, earth-abundant alternatives with superior high-temperature stability [11][12][13]. Donor-doped (n-type) strontium titanate (SrTiO 3 ; STO) is regarded as a promising oxide TE, with a high melting point of 2080 • C [14] and an outstanding PF up to 3600 µW m −1 K −2 at room temperature due to a large Seebeck coefficient [15].…”