A bipolar plate for a battery includes a metal sheet that has a first side and a second, opposite side. The metal sheet is folded so as to form a series of loops on the second side. The loops are spaced apart to define flow field passages therebetween on the second side. Each of the loops is bonded along an edge at the first side so as to enclose an internal passage.

Microcracked and crack-free catalyst layers such as for electrodes in electrochemical cells (e.g., fuel cells) and method of making the same are disclosed. The microcracks may improve durability by better tolerating stresses without inducing or propagating into macrocracks. The microcracks also improve efficiency by providing reactant (e.g., oxygen) passages to catalyst in the catalyst layer. The microcracks may be formed in a predetermined pattern to further localize additional reactant passages is conventionally starved or more starved locations.

A membrane electrode assembly (MEA) for a fuel cell and an electrolyzer is provided. The MEA includes a first electrode layer, a second electrode layer disposed opposite the first electrode layer, a polymer electrolyte membrane extending between the first electrode layer and the second electrode layer, a gas diffusion layer (GDL) disposed adjacent the first and second electrode layers. A bifunctional catalyst comprising a noble metal supported on a metal oxide compound is disposed in at least one of polymer electrolyte membrane, first and second electrodes, and GDLs. The noble metal comprises at least one of Pt and Pd. The metal oxide compound comprises at least one of CeO.sub.2, CexZr.sub.yO.sub.4, MnO.sub.2, CeEO, MnEOx, and CoEOx. The ratio of the noble metal to the metal oxide compound is 1%-80% by weight.