Abstract
| Language | English |
|---|---|
| Pages | 4786–4793 |
| Number of pages | 8 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 10 |
| Issue number | 5 |
| Early online date | 9 Jan 2018 |
| DOIs | |
| Publication status | Published - 7 Feb 2018 |
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Grain by grain compositional variations and interstitial metals – a new route towards achieving high performance in half-Heusler thermoelectrics. / Barczak, Sonia; Halpin, John; Buckman, Jim; Decourt, Rodolphe; Pollet, Michaël; Smith, Ronald I.; MacLaren, Donald A.; Bos, Jan-Willem G.
In: ACS Applied Materials and Interfaces, Vol. 10, No. 5, 07.02.2018, p. 4786–4793.Research output: Contribution to journal › Article
TY - JOUR
T1 - Grain by grain compositional variations and interstitial metals – a new route towards achieving high performance in half-Heusler thermoelectrics
AU - Barczak, Sonia
AU - Halpin, John
AU - Buckman, Jim
AU - Decourt, Rodolphe
AU - Pollet, Michaël
AU - Smith, Ronald I.
AU - MacLaren, Donald A.
AU - Bos, Jan-Willem G.
PY - 2018/2/7
Y1 - 2018/2/7
N2 - Half-Heusler alloys based on TiNiSn are promising thermoelectric materials characterised by large power factors, good mechanical and thermal stabilities; but they are limited by large thermal conductivities. A variety of strategies have been used to disrupt their thermal transport, including alloying with heavy, generally expensive, elements and nanostructuring, enabling figures of merit, ZT ≥ 1 at elevated temperatures (>773 K). Here, we demonstrate an alternative strategy that is based around the partial segregation of excess Cu leading to grain-by-grain compositional variations, the formation of extruded Cu ‘wetting’ layers between grains and – most importantly – the presence of statistically distributed interstitials that reduce the thermal conductivity effectively through point-defect scattering. Our best TiNiCuySn (y ≤ 0.1) compositions have a temperature-averaged ZTdevice = 0.3-0.4 and estimated leg power outputs of 6-7 W cm-2 in the 323-773 K temperature range. This is a significant development as these materials were prepared using a straightforward processing method, do not contain any toxic, expensive or scarce elements and are therefore promising candidates for large scale production.
AB - Half-Heusler alloys based on TiNiSn are promising thermoelectric materials characterised by large power factors, good mechanical and thermal stabilities; but they are limited by large thermal conductivities. A variety of strategies have been used to disrupt their thermal transport, including alloying with heavy, generally expensive, elements and nanostructuring, enabling figures of merit, ZT ≥ 1 at elevated temperatures (>773 K). Here, we demonstrate an alternative strategy that is based around the partial segregation of excess Cu leading to grain-by-grain compositional variations, the formation of extruded Cu ‘wetting’ layers between grains and – most importantly – the presence of statistically distributed interstitials that reduce the thermal conductivity effectively through point-defect scattering. Our best TiNiCuySn (y ≤ 0.1) compositions have a temperature-averaged ZTdevice = 0.3-0.4 and estimated leg power outputs of 6-7 W cm-2 in the 323-773 K temperature range. This is a significant development as these materials were prepared using a straightforward processing method, do not contain any toxic, expensive or scarce elements and are therefore promising candidates for large scale production.
U2 - 10.1021/acsami.7b14525
DO - 10.1021/acsami.7b14525
M3 - Article
VL - 10
SP - 4786
EP - 4793
JO - ACS Applied Materials and Interfaces
T2 - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
SN - 1944-8244
IS - 5
ER -