Page 62 - ILLS Annual Report 2018

CHEMISTRY AND CHRYSTALLOGRAPHY
Emmanuel Guilmeau. French
Laboratoire CRISMAT, France
‘I received a PhD in materials chemistry in
2003 from the University of Caen. My research interests focus on the discovery/processing of new materials, and especially on the compositional design of thermoelectrics.
I use different characterisation techniques to investigate chemical and physical properties.’
Producing high-performance thermoelectric bulk colusite by process-controlled structural disordering
High-intensity two-axis powder diffractometer D1B
The search for optimised thermoelectric materials poses an interesting conundrum because of
the delicate balance that must be achieved between charge and thermal transport. In addition, practical factors such as cost and manufacturability play an important role when discussing materials and properties. We have made substantial progress in addressing these issues in synthetic colusite, Cu26V2Sn6S32, by controlling the densification process and forming short-to-medium range structural defects [1].
AUTHORS
C. Bourgès, O.I. Lebedev, V. Hardy, R. Daou and E. Guilmeau (CRISMAT, Caen, France)
Y. Bouyrie and M. Ohta (National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan)
P. Lemoine (Institut des Sciences Chimiques de Rennes, Rennes, France) K. Suekuni (Kyushu University, Fukuoka, Japan)
V. Nassif (Grenoble Alpes University and CNRS−NEEL Institute, Grenoble, France)
Y. Miyazaki (Tohoku University, Sendai, Japan)
A.R. Supka, R. Al Rahal Al Orabi and M. Fornari (Central Michigan University, Mt. Pleasant, USA)
ARTICLE FROM
J. Am. Chem. Soc. (2018)—doi: 10.1021/jacs.7b11224
REFERENCES
[1] C. Bourgès, Y. Bouyrie, A. Supka, R. Al Rahal Al Orabi,
P. Lemoine, O.I. Lebedev, M. Ohta, K. Suekuni, V. Nassif,
V. Hardy, R. Daou, M. Fornari, Y. Miyazaki and E. Guilmeau, J. Amer. Chem. Soc. 140 (2018) 2186
[2] K. Suekuni, F.S. Kim, H. Nishiate, M. Ohta, H.I. Tanaka and T. Takabatake, Appl. Phys. Lett. 105 (2014) 132107
[3] P.G. Spry, S. Merlino, S. Wang, X. Zhang and P.R. Buseck, Am. Mineral. 79 (1994) 750
[4] O.V Frank-Kamenetskaya, I.V Rozhdestvenskaya and L.A. Yanulova, J. Struct. Chem. 43 (2002) 89
The design and optimisation of thermoelectric materials
rely on the intricate balance between thermopower
(S), electrical resistivity (ρ) and thermal conductivity (κ);
perfecting such a balance is key to improving the figure of
merit (ZT = S2 T) and energy recovery systems. Synthetic ρκ
colusite, Cu26V2Sn6S32, represents a prototypical complex sulphide (i.e. a large unit cell with 66 atoms and light mass elements) combining p-type metallic behaviour and low lattice thermal conductivity [2]. However, the origin of the low thermal conductivity in colusite is not well understood and the full potential of Cu26V2Sn6S32 as an advanced thermoelectric material has not been fully explored. Our goal was to understand and optimise the thermoelectric properties of Cu26V2Sn6S32 colusite by controlling the densification temperature and method.
In this context, a reproducible and scalable powder synthesis was performed by mechanical alloying, followed by densification using two different consolidation techniques: spark plasma sintering at 873 K and hot pressing at 1023 K.
ANNUAL REPORT 2018
Figure 1
Combined Rietveld refinement of a) XRPD and b) NPD patterns of the colusite sample sintered at 873 K and recorded at room temperature.