3D-Printed, Scalable, Membrane-less Electrolyzer for Hydrogen Production: Design and Optimization

The article presents design and performance-optimization of 3D printed membrane-less electrolyzer with four arrangements of mesh/foam electrodes (with no gap: MENG-1 and MENG-2; with gap: MEWG and FEWG) for hydrogen production. The performance, in terms of current density, purity and crossover of the hydrogen gas, is experimentally analyzed with varying flow rates of electrolyte at temperatures 30.4 and 60 °C. Results show that increasing flow rates increase current density in order: MENG-1 < MENG-2 < MEWG < FEWG – the performance trend follows the combined effect and synergy between increased drag on gas bubbles, surface-renewal of the electrode for improved electrochemical kinetics, and reduced flooding effect near the electrode surface stemming from gap-allowance. The enhancement in the purity of hydrogen gas and its reduced migration is achieved in the same order. Highest purity of the hydrogen gas is 99.20%, and its crossover is 2.13%, at 30.4 °C for FEWG electrode arrangement. Higher temperature operation marginally affects the performance due to increased migration of the gases. At 60 °C, purity and crossover are (95.63, 3.19)% for FEWG. This design of the presented membrane-less electrolyzer is simpler, and the device can be scaled up by increasing the size and number of electrodes for higher production of hydrogen gas required for commercial applications.