Nano-micro-porous skutterudites with 100% enhancement in ZT for high performance thermoelectricity
Abstract
Increasing energy demands require new materials, e.g., thermoelectrics, for efficient energy conversion of fossil fuels. However, their low figure of merit (ZT) limits widespread applications. Nanostructuring has been an effective way of lowering the thermal conductivity. However, grain growth at elevated temperature is still a big concern, for otherwise expected to be long-lasting thermoelectric generators. Here, we report a porous architecture containing nano- to micrometer size irregularly shaped and randomly oriented pores, scattering a wide spectrum of phonons without employing the conventional rattling phenomenon. Lattice thermal conductivity reaches the phonon glass limit. This design yields >100% enhancement in ZT, as compared to the pristine sample. An unprecedented and very promising ZT of 1.6 is obtained for Co23.4Sb69.1Si1.5Te6.0 alloy, by far the highest ZT ever reported for un-filled skutterudites, with further benefits, i.e. rare-earth-free and improved oxidation resistance enabling simple processing.
- Publication:
-
Nano Energy
- Pub Date:
- January 2017
- DOI:
- 10.1016/j.nanoen.2016.11.016
- Bibcode:
- 2017NEne...31..152K
- Keywords:
-
- ZT;
- Figure of Merit;
- PGEC;
- Phonon Glass Electron Crystal;
- CIP;
- Cold Isostatic Press;
- XRD;
- X-ray Diffraction;
- SPS;
- Spark Plasma Sintering;
- DSC;
- Differential Scanning Calorimetry;
- Cp;
- Heat Capacity;
- SEM;
- Scanning Electron Microscope;
- LDA;
- Local Density Approximation;
- BH;
- von Barth-Hedin;
- DOS;
- Density Of States;
- EDX;
- Energy Dispersive X-ray;
- RE;
- Rare Earth;
- Energy conversion;
- Materials science;
- Semiconductors;
- Solid-state chemistry;
- Thermoelectric materials