REDOXSCAN · Redox Flow Battery Spin Characterization by Advanced Electron Paramagnetic Resonance

The REDOXSCAN will pioneer the use of high-frequency (HF, ≥100 GHz) and ultra-fast electron paramagnetic resonance (EPR) spectroscopy for real-time monitoring of vanadium redox flow battery (VRFB) electrolytes. VRFBs are attractive devices for large-scale energy storage, yet their widespread deployment is constrained by degradation processes, vanadium ion crossover, electrolyte instability and side reactions at high potentials. The main goal of REDOXSCAN is the development of a unique setup required for VRFBs' electrolyte characterization. Diagnosing and mitigating pathways at the microscopic level goes beyond state of art in integration of advanced EPR for battery research. This novel approach enables real-time determination of the state-of-charge (SOC) through identification of vanadium redox couples by HFEPR and rapid scan techniques. Ultra-fast EPR spin trapping will, for the first time, provide microscopic insight into radical formation and ROS-driven degradation in VRFBs electrolytes. Experimental SOC quantification from EPR spectra will be correlated with electrochemical models, such as diffusion-based simulations developed in the HORIZON-MSCA project SPACER, providing robust validation and guiding electrolyte and electrode optimization.By integrating advanced methodologies into VRFB research, this project addresses critical gaps in instrumentation and methodology, accelerates the development of optimized battery components, and supports the design of resilient large-scale energy storage systems. The results will directly contribute to the EU’s goals for carbon neutrality, circular economy, and sustainable green technologies under the European Green Deal. The project will be carried out under the supervision of Dr. Petr Neugebauer at the Central European Institute of Technology (CEITEC), Brno University of Technology, Czech Republic, which offers cutting edge infrastructure for high-frequency EPR and rapid scan spectroscopy.