Abstract: Described herein are salt-splitting electrolysis systems, which comprise flow electrodes, and methods of operating such systems. Specifically, the flow electrodes comprise active particles (suspended in a solvent) with catalysts. These catalysts are configured to react with either cations or anions, provided in a feed stream. The flow electrodes allow using the same system for different feed streams, e.g., by flowing different types of electrodes through the system. Furthermore, the flow electrodes allow in-situ catalyst reconditioning. For example, the active particles can be flown from the current collectors to respective recovery devices where the particles are discharged or subjected to a reverse potential. The active particles can be conductive and provide more desirable electrical field distribution between the current collectors resulting in greater ionic mobility.