Performance of an Electrode Topology for Alkaline Water Electrolysis Under Specific Operating Conditions

Abstract

Channels were machined over the active area of a 316L stainless steel electrode, in vertical electrode position, with a width of 5 mm that is reduced to 1 mm and then widened again. For its construction, electro discharge machining was selected since it also allows obtaining different degrees of roughness, which can favor the detachment of bubbles to a larger quantity. Analysis of its performance was carried out at an initial operating temperature of 30 ° C and at seven different distances between electrodes, namely: 9.45; 7.45; 6.35; 5.80; 4.30; 2.80 and 2.45 in millimeters, in order to determine the one with the lowest energy consumption to produce a fixed amount of hydrogen. Results obtained from the evaluated distances show that as the distance between electrodes becomes smaller, so do the electrical and transport resistances. The percentage increase in the current density for the distances of 9.45 and 2.45 mm, with respect to the applied potential difference, shows that at 2.2 V, it is above 80% (in current density) and maintained, with small fluctuations throughout the range of applied voltages. Therefore, using the same amount of energy, a greater volume of hydrogen is obtained.