Electrode fabrication for proton exchange membrane fuel cells by pulse electrodeposition

For low platinum loading, electrodeposition is used to fabricate electrodes for proton exchange membrane fuel cells. Pulse electrodeposition can form platinum deposits of about 15 A directly on the surface of the electrode. With direct current electrodeposition at a current density of 25 mA cm^-2, the electrode exhibits the best performance. At greater currents, the performance drops sharply because of the growth of dendritic crystals and the loss of the deposition layer due to generation of hydrogen. At a deposition current density of 50 mA cm^-2, the optimum conditions of pulse electrodeposition are 100 ms on-time and 300 ms off-time, and the performance of the electrode is 320 mA cm^-2 at 0.7 V. Also, it is found that the brushing method for making carbon electrodes is favourable for electrodeposition because it can supply much more sites for the formation of nuclei.