Optimally Engineered Flow-through Electrodes Using Automatic Design Algorithms and Additive Manufacturing

Flow batteries are a promising technology for large scale energy storage and load balancing from intermittent power sources, but their viability hinges on our ability to attain high-power outputs while minimizing costs and meeting performance constraints. Controlling fluid flow, active species distribution, and mass transport in the electrode has a dramatic impact on cell power and efficiency. However, this control is often limited to changing a quasi-two-dimensional flow field and selecting bulk properties of a monolithic electrode. This can lead to non-uniform reaction rates, underutilized regions of the flow cell, and can limit the ultimate performance of the devices. We propose an alternative approach which seeks to control the fluid distribution in the cell by controlling the electrode geometry. Our approach is enabled by additive manufacturing techniques which allow us to directly build three-dimensional morphologies. Further, to determine effective electrode geometries, we employ topology optimization techniques that couple solution of the forward electrochemical problem over the full electrode domain with gradient-based optimization. The output of our code is a three-dimensional CAD representation which optimizes over specific performance metrics and which can be used to print functional electrodes. We will demonstrate the process for generating the electrodes using our optimization framework and present experiments comparing the performance of the optimized geometries across designs and against conventional electrodes. This work provides a systematic path toward automatic design of engineered electrodes with precise control over the fluid and species distribution. LLNL-ABS-764035 This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.