Image-Based Mechanical Balancing of Reservoir Volumes During Benchtop Flow Battery Operation

The long-term maintenance of stable redox-flow-battery performance requires a strategy to manage dynamic volume imbalances between electrolyte reservoirs. Even with ion-selective membranes as separators, bulk liquid exchange can occur within the reactor because pressure differences across its positive and negative chambers. Disproportionation chemistries, wherein both reservoirs have identical composition in discharged state, tolerate species crossover reversibly. These make possible use low-cost porous but such materials are more hydraulically permeable. Here we propose an approach mitigate reservoir imbalance, using nonaqueous vanadium acetylacetonate disproportionation chemistry test platform. We demonstrate benchtop-scale control scheme, which relies on camera that monitors volumes linked microcontroller regulates differential flowrate flow streams. balancing apparatus introduces no extra wetted components enables real-time measurements intra-cycle imbalance due electroosmosis. All software firmware is made available for community use.