Vendredi 30 janvier 2026 à 11h00, salle 259, IUSTI
The past few decades have shown a rapid and continuous exhaustion of the available energy resources making energy storage and conversion technologies a critical element in future smart grid and electrical vehicle applications. In this context, microscale energy conversion devices offer one of the best combinations of efficiency, cost, flexibility, and power density, with microfluidic technologies leading the way in this aspect. To accompany these technological developments and their miniaturisation toward the microscale and beyond, advanced characterization methods need to be continuously improved, in particular in the fields of heat and mass transfer imaging. In this presentation, I will first introduce the development made in our group with on-chip energy conversion devices based on redox flow batteries and water electrolysers. These devices were microfabricated using microfluidic technologies comprising microchannels, electrodes and polymer electrolytes. Then, while operating them, spectro-electrochemical imaging in the visible and infrared ranges were developed to fully map the concentration fields, the electrochemical kinetics and the water transport in polymer electrolyte membrane at microscale. Experimental, theorical and signal processing methods used to perform such characterizations will be presented in this talk. In the second part of the seminar, I will introduce our recent works made to image heat and mass transfers in 3D at the microscale. Such developments are based on the material refractive index dependency with temperature, the so call “thermo-transmittance”. By measuring these variations in laminography, we were able to reconstruct the 3D thermal fields in glass wafers and polymers used in microfluidic, such as PDMS. The details of our experimental setup and reconstruction algorithm will be described during the talk. These recent works open the path toward contactless methods to probe 3D heat transfers in complex architecture of on-chip energy conversion devices.