A practical beginner's guide to developing a 3D printed electrochemical cell for soluble lead flow batteries

Flow batteries are promising for stationary energy storage, and soluble lead flow batteries (SLFBs) stand out for their membrane-less and simple design. However, their development is still limited by the lack of accessible and reproducible laboratory test cells. In this work, a 3D-printed electrochemical cell was developed and validated for SLFB investigation using graphite electrodes and stainless-steel screw current collectors. The cell was first benchmarked with the ferri/ferrocyanide redox couple and then used for electrolyte screening with varying concentrations of lead methanesulfonate and methanesulfonic acid. The selected condition was evaluated using electrochemical measurements and post-cycling scanning electron microscopy and X-ray diffraction. Five independently assembled cells showed coefficients of variation of 1.2 to 4.0% in fifth-cycle efficiencies, supporting electrochemical repeatability. Using 1.0 M LMS and 0.5 M MSA, the cell completed 400 cycles at 20 mA cm −2 with progressive performance degradation. Coulombic and energy efficiencies reached maximum values of 92% and 71% and decreased to approximately 69% and 50%, respectively, at cycle 400. Subsequent charging-voltage excursions and loss of discharge capability marked operational failure. Morphological and structural analyses showed a dense β-PbO 2 rich deposit at the positive electrode and dendritic Pb growth at the negative electrode, linking performance decay to deposit evolution during cycling. These results demonstrate that the proposed cell is an accessible and reproducible platform for SLFB research.