Thermoelectric materials promise to create additional efficiencies in energy management by harvesting the energy of waste heat and converting it to electricity. We introduce 2D Sb2Si2Te6 as a promising new high-performance thermoelectric material. Sb2Si2Te6 exhibits an intrinsically high thermoelectric figure of merit ZT value of ∼1.08 at 823 K. We then devise a unique cellular nanostructure by a post-synthetic reaction strategy that forms in situ Si2Te3 nanosheets, which serve as an effective barrier to heat propagation, yielding an ∼40% reduction in the already very low lattice thermal conductivity to ∼0.29 Wm−1K−1 at 823 K. The cellular nanostructure enables a very high ZT value of ∼1.65 at 823 K for this new material and a high average ZT value of 0.98 (400–823 K). We describe the novel cellular nanostructure design and a single-step chemical route to achieve it, highlighting a potentially new and effective general design strategy for achieving high thermoelectric performance.
Bibliographical noteFunding Information:
We acknowledge the support from the Department of Energy , Office of Science Basic Energy Sciences under grant DE-SC0014520 , DOE Office of Science (sample preparation, synthesis, XRD, TE measurements, TEM measurements, and DFT calculations, Northwestern University), and from the Deutsche Forschungsgemeinschaft DFG in the framework of SPP 1666 under grant PF 324/4-1 (AP). This work made use of the EPIC facilities of Northwestern’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource ( NSF ECCS-1542205 ); the MRSEC program (NSF DMR-1720139 ) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation ; and the State of Illinois, through the IIN. User Facilities are supported by the Office of Science of the U.S. Department of Energy under contract no. DE-AC02-06CH11357 and DE-AC02-05CH11231 and the ONR funding-PYSA measurements (ONR grant N00014-18-1-2102 ). Access to facilities of high-performance computational resources at the Northwestern University is acknowledged. The authors also acknowledge National Natural Science Foundation of China ( 61728401 ), Singapore MOE AcRF Tier 2 under grant nos. 2018-T2-1-010 and 2017-T2-2-069 , Singapore A*STAR Pharos Program SERC 1527200021 and 1527200022 , and the support from FACTs of Nanyang Technological University for sample analysis.
- Seebeck coefficient
- cellular nanostructure
- minority blocking
- narrow gap semiconductors
- waste heat recovery