About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
Energy Materials for Sustainable Development
|
| Presentation Title |
High Entropy Oxides with Ultra-Low Thermal Conductivity: Emerging Class of Oxide Thermoelectrics |
| Author(s) |
Vivek Kumar, Ritwik Banerjee, Subhra Sourav Jana, Tanmoy Maiti |
| On-Site Speaker (Planned) |
Tanmoy Maiti |
| Abstract Scope |
Although oxides showed lot of promises as thermoelectric materials, their figure-of-merit, zT is low primarily because of high lattice thermal conductivity (k_l). Researchers found it challenging to reduce k_l of oxides possessing low phonon mean-free-path (Lphonon). Recently, we posited a strategy of achieving ultra-low k_l in high entropy perovskite (HEP) to induce more anharmonicity causing enhanced multi-phonon scattering. Sr(TiFeNbMoCr)O3 HEP showed the lowest Lphonon among SrTiO3 based materials resulting in ultralow k~0.7 W/mK. In-depth analysis of phonon transport mechanism in HEP performed by Debye-Callaway model suggests that presence of 5 cations in B-site causes enhanced anharmonicity leading to higher order phonon scattering. We demonstrated synergistic combination of large Seebeck and record low k in high entropy niobate (Sr0.2Ba0.2Li0.2K0.2Na0.2)Nb2O6, with tungsten-bronze structure. We fabricated four-legged TEG prototype using HEP, demonstrating maximum power output and power density of 95.5 mW and 2.9 mW/m2, which are highest values ever reported for oxides-based TEG. |