Finite Element Simulation Approach to Optimize Thermal Behavior in Thermoelectric Interconnected Nanofiber 3D Networks

The fabrication of interconnected nanostructures of thermoelectric materials by means of electrochemical growth inside nanoporous templates has been explored recently [1-2]. The production of these networks, especially those produced in high ordered 3D nanoporous alumina templates, have been reported as an excellent method to reduce thermal flux along thermoelectric materials [3]. This approach would allow increasing thermoelectric efficiency by reducing thermal conductivity while having a small effect on electric conductivity.<br/>In the present work we focussed on the fabrication of interconnected nanostructures, using commercial nanoporous filters as templates. In order to optimize the type of structure, and geometrical parameters having an influence on the thermal conductivity of the structure, the thermal behaviour of such nanostructures has been studied using the finite elements method. The use of python script has been a key tool in order to produce the actual geometries, due to the high randomness in parameters such as nanowire section radii, nanowire positions or nanowire orientations. Thermal losses in the nanowire walls have been simplified to a convection model, allowing qualitative comparison between the studied geometries, and facilitating the analysis of the individual geometrical parameters in order to spot the optimal 3D interconnected nanonetwork. This allowed us to determine the optimal parameters leading to the lowest thermal transfer and thermal conductivity, and thus increasing the thermoelectric efficiency.<br/><br/>[1] A. Ruiz-Clavijo, O. Caballero-Calero and M. Martín-González, Nanomaterials, 8 (2018) 345 (http://dx.doi.org/10.3390/nano8050345)<br/>[2] M. Rauber, I. Alber, S. Müller, R. Neumann, O. Picht, C. Roth, A. Schökel, M.E. Toimil-Molares and W. Ensinger, Nano Lett. 11 (2011) 2304–2310 (https://doi.org/10.1021/nl2005516)<br/>[3] A. Ruiz-Clavijo., O. Caballero-Calero, C. V. Manzano, X. Maeder, A. Beardo, X. Cartoixa, X. Álvarez and M. Martín-González, ACS Applied Energy Materials, 4 (2021). 13556-13566 (https://doi.org/10.1021/acsaem.1c02129)