Solar Tuning: Operando Imaging for Durable Solar-driven CO2 Electrolysis

Objective

"Solar Tuning tackles the central barrier to renewable e-fuels: instability in solar-driven CO2 electrolysis. This project will build an operando monitoring platform that observes reaction sites inside short-stack electrolysers in real time and automatically adjusts the operating conditions. Polarisation imaging will measure quantitative imaging observables (birefringence, depolarisation, scattering) that linked to gas evolution, salt formation, and catalyst change. In-line ultrafast laser spectroscopy will capture charge-carrier dynamics from femtoseconds to nanoseconds. Physics-informed models will combine these data to choose the optimised operating conditions. This platform will then automatically tune the flow, electrolyte composition, illumination, magnetic and electric fields, temperature, and other parameters to keep the performance stable. The ""Solar Tuning"" platform will be validated at EPFL with industrial collaborators to ensure relevance for system integration, stack development, and endurance testing. Protocols, datasets, and reference implementations will be shared under FAIR principles. Project targets are: (i) at least three quantitative optical observables at ≥20 Hz with ≤1 µm spatial resolution; (ii) ≥100 h continuous operation with ≤5% loss in solar-to-chemical efficiency under standard sunlight; and (iii) proof-of-concept outdoor performance. By enabling durable CO2-to-fuel conversion, Solar Tuning directly supports the European Green Deal and REPowerEU, strengthening Europe’s competitiveness in renewable e-fuels. "