PDDA coating method on surface of catalyst to form carbon shell for enhancing durability of polymer electrolyte membrane fuel cells

Abstract

Construction of a physical protective layer on the catalyst surface of platinum-based catalysts in fuel cells to increase their durability has attracted attention of researchers. In particular, the carbon shell is suitable as a coating material because it covers relatively few active sites of Pt compared to other coating materials. However, the conventional carbon shell formation method is complex, time-consuming, and does not form a uniform layer easily. In this study, a new method for attaching a poly(diallyldimethylammonium chloride)(PDDA) polymer to the catalyst surface and forming a carbon shell through heat treatment was proposed. This method can easily forms a thin and uniform carbon shell with a thickness of <= 1 nm, minimizes performance reduction, and maintains superior durability of catalyst. For the 120-h single cell durability test, the current density at 0.6 V and maximum power density of Pt/C without carbon shell decreased by 32.3 % and 26.5 %, respectively, compared to the initial performance, whereas it was confirmed that 5.9 % and 9.0 % were reduced, respectively, in the case of carbon-shelled Pt/C manufactured in this study. This new method of carbon shell formation is expected to be easily applicable to various nanoparticle-based catalysts that require a physical protective layer to ensure durability.