Laboratory name: Institut Lumière Matière
CNRS identification code: UMR5306 Université Lyon 1-CNRS
Internship director’surname: JOLY Laurent, MERABIA Samy
e-mail: laurent.joly@univ-lyon1.fr Phone number: 04 724 326 11
Web page: [ilm-perso.univ-lyon1.fr]
Internship location: Villeurbanne, France


Thesis possibility after internship: YES
Funding: YES If YES, which type of funding: ANR project

High performance nanofluidic thermoelectricity using smooth polarized surfaces

Nanofluidic systems offer great promises for new energy harvesting technologies. In particular, charged nanochannels filled with salted water could produce electricity from waste heat, with an efficiency reaching that of the best solid-state thermoelectric materials [1], when boosted by liquid-solid slip arising on low-friction surfaces. However, high performance also requires high surface charge, which is detrimental to slip. Nevertheless, we have recently shown that smooth polarized surfaces -especially graphene- display a favorable charge-slip coupling [2]; consequently, these surfaces could provide excellent thermoelectric conversion perfomances. In that context, we would like to identify especially promising configurations with high conversion efficiency by studying thermoelectric energy conversion in graphene nanochannels, in collaboration with the group of S. Hardt in Darmstadt, Germany (smoothE project, funded by the ANR). To develop a comprehensive picture of thermoelectricity in nanofluidic channels, we will use a multiscale approach, combining atomistic simulations in Lyon [1,2], to capture molecular effects in the nanometric vicinity of the interface, and continuum-mechanical simulations in Darmstadt [3], to describe the entire system at a larger scale. The internship, which can be followed by a PhD (funded by the ANR), will focus on the atomistic modeling part of the project.

The objectives of the internship are: to understand at the nanometric scale the generic molecular mechanisms of thermoelectricity at liquid-solid interfaces; to investigate the specificities of polarized graphene (fluctuating surface charge, role of defects); and to explore a wide range of working conditions (polarization potential, salt type and concentration) to identify cases with optimal performance. The student will use molecular dynamics (MD) simulations, based on empirical interaction potentials. The thermo-electric response will be measured with different non-equilibrium MD setups, and related to static and dynamical properties of the interface computed independently, using semi-analytical descriptions (e.g. modified Poisson-Boltzmann equation).

[1] L. Fu, L. Joly, S. Merabia, Phys. Rev. Lett. 123, 138001 (2019);
[2] Y. Xie, L. Fu, T. Niehaus, L. Joly, Phys. Rev. Lett. 125, 014501 (2020);
[3] M. Dietzel and S. Hardt, Phys. Rev. Lett. 116, 225901 (2016).