An improved catalyst-coated membrane structure for PEM water electrolyzer

To develop the proton exchange membrane (PEM) water electrolyzers with high performance and stability, a catalyst-coated membrane (CCM) with a five-layer structure was developed. The performance of the five-layer CCM was evaluated and compared with a conventional three-layer CCM and a CCM hot-pressed at a higher temperature via converting the protonated form of Nafion to Na+ form and then being reprotonated back to H+ form after hot-pressing. The five-layer CCM exhibits the highest performance and stability, attributed to the expansion of the triple-phase boundaries for electrochemical reactions and the improvement of contact and mass-transfer resistance.