Abstract
Zintl phases are excellent candidates for high-efficiency thermoelectrics (TEs) due to their extremely low lattice thermal conductivity. The manufacturing of an all-Zintl module is particularly attractive for practical applications, as it alleviates concerns regarding the electronic, thermal, and mechanical compatibility of the p- A nd n-type legs. To date, a large majority of Zintl phases have been realized as p-type TE materials. Our recent discovery of n-type transport in Ba-doped KAlSb4 and KGaSb4 has helped demonstrate the potential of n-type Zintl thermoelectrics. In this paper, we report the experimental discovery of 4 ABX4 Zintl phases: RbAlSb4, RbGaSb4, CsAlSb4, and CsGaSb4. Transport measurements on Ba-doped RbGaSb4 and CsGaSb4 demonstrate near glassy lattice thermal conductivity (<0.5 W m-1 K-1, 350 °C) and lightly doped n-type transport. However, the doping efficiency of Ba in RbGaSb4 and CsGaSb4 is significantly impeded when compared to our prior work on KGaSb4. To investigate the underlying mechanism, we performed first-principles defect calculations and found that the effect of compensating alkali metal vacancies increases in the Rb- A nd Cs-based analogues. Considering the TE potential of the known ABX4 n-type materials, we have also performed a computational survey over 27 plausible compositions where A = (K, Rb, Cs), B = (Al, Ga, In), and X = (As, Sb, Bi) to investigate the effect of chemistry on potential TE performance.
Original language | English |
---|---|
Pages (from-to) | 2182-2191 |
Number of pages | 10 |
Journal | ACS Applied Energy Materials |
Volume | 3 |
Issue number | 3 |
DOIs | |
State | Published - Mar 23 2020 |
Externally published | Yes |
Funding
B.R.O., P.G., V.S, and E.S.T. acknowledge support from National Science Foundation Grant 1729594. This work was supported by the NASA Science Missions Directorate’s Radioisotope Power Systems Thermoelectric Technology Development Project. B.R.O. also acknowledges support from the California NanoSystems Institute through the Elings Fellowship program. S.D.W. acknowledges support from 538 DOE, Office of Science, Basic Energy Sciences, under Award DE-SC0017752. S.D.W. also acknowledges support from the UC Santa Barbara NSF Quantum Foundry funded via the Q-AMASE-i initiative under award DMR-1906325. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DE-AC02-06CH11357. The research was performed using computational resources sponsored by the Department of Energy’s Office of Energy Efficiency and Renewable Energy and located at the National Renewable Energy Laboratory.
Keywords
- defect calculations
- doping
- n-type Zintl
- n-type thermoelectric