Cation Exchange Membranes for Fuel Cells- A Patent Review

Ion exchange membranes-based technology, as a non-hazardous technology in nature, is extending towards the newly emerging fuel cells beyond its successful application in various industrial processes, e.g. electrolysis, electrodialysis, diffusion dialysis, etc. Ever since the famous DuPont product Nafion®, a large number of cation exchange membranes for fuel cells application (known as proton exchange membranes) have been prepared to make fuel cells reliable, durable and feasible. Since most of commercial products originate directly from patents, it is of great importance, at the time when proton exchange membrane fuel cells are on the brink of commercialization, to make a special review focusing on proton exchange membranes reported in patents. To get a better understanding of the state of the art of proton exchange membranes from a viewpoint of patents, most relevant patents during the last decade are surveyed in this review and some critical comments on the tendency and prospect of proton exchange membranes are made.