Public Thesis Defense of Romain Hanus - ICTEAM
sst |
Micro energy harvesting using reverse electrodialysis with porous silicon membranes
Tuesday March 24, 2026 - 4:15pm - Auditorium SUD08 - Place Croix du Sud, 1 - 1348 Louvain-la-Neuve
This thesis investigates porous silicon (pSi) as a CMOS-compatible nanoporous ion-exchange membrane for harvesting salinity-gradient power through reverse electrodialysis (RED), with the longer-term perspective of powering autonomous IoT/AIoT sensor nodes. While classical RED relies on dense polymer ion-exchange membranes optimized for large-scale stacks, nanofluidic RED (nRED) leverages surface-charge–driven transport in confined pores, offering a route toward miniaturized energy harvesters. However, translating single-pore demonstrations into integrable, scalable membrane technologies remains challenging, particularly with common platforms such as anodic aluminum oxide due to integration constraints.
To bridge this gap, the work develops and validates porous silicon membranes tailored for nRED. First, a theoretical and numerical framework based on charged nanopores is established to analyze how pore geometry, electrolyte concentration, and surface charge density govern permselectivity, ionic resistance, and power generation. Second, a dedicated experimental benchmarking platform is implemented to characterize open-circuit voltage, internal resistance, and power density under controlled KCl salinity gradients. Two fabrication routes are developed, self-supported and free-standing membranes, followed by systematic electrochemical characterization.
The thesis reports the first demonstration of nRED using porous silicon as the ion-selective material. Optimized free-standing pSi membranes (90 µm thick) achieved a maximum power density of 1.33 mW/cm² under a 10/1 mM KCl gradient, driven by strong double-layer overlap and low ionic resistance. Performance enhancement strategies are explored via hybrid active/support layers fabricated in a single anodization step, and by implementing an adaptive surface-charge regulation model. Beyond energy harvesting, the results provide transferable insight into pSi surface chemistry and selective ion transport relevant to iontronics and lab-on-chip systems.
Jury members
Prof. Laurent A. Francis (UCLouvain) Supervisor
Prof. Christophe Craeye (UCLouvain) Chairperson
Prof. Denis Flandre (UCLouvain) Secretary
Prof. Tristan Gilet (Uliège)
Prof. Abel Santos (University of Adelaide, Australia)