Composite Materials with Combined Electronic and Ionic Properties

In this work, we develop a new type of composite material that combines both electrocatalytic and ionic properties, by doping a silver metal catalyst with an anion-conducting ionomer at the molecular level. We show that ionomer entrapment into the silver metallic structure is possible, imparting unique properties to the catalytic character of the metallic silver. The novel composite material is tested as the cathode electrode of fuel cells, showing significant improvement in cell performance as compared with the undoped counterpart. This new type of material may then replace the current design of electrodes in advanced fuel cells or other electrochemical devices. The possibility to merge different properties into one composite material by molecular entrapment in metals can open the way to new materials, leading to unexplored fields and applications. Materials for energy applications, such as fuel cells, have drawn great attention in recent years due to the global quest for alternative energy sources. Specifically for fuel cells, the materials research focuses on the development of non-Pt catalysts due to the high price and limited sources of platinum. To date, the development deals with the improvement of the electrocatalyst and the ionomer of the cell separately. In this paper, the synthesis of a composite material that combines both components, ionomer@Ag, is shown. This combination is achieved by the entrapment of the ionomer in a silver metallic matrix. The ionomer@Ag preserves both ionic and electronic conductivities. Moreover, it exhibits enhanced electrocatalytic activity in an anion-exchange membrane fuel cell compared with pure silver catalyst. This can lead to new and more efficient composite-based fuel cell design. Currently in fuel cell state-of-the-art research, studies are divided on separate improvements of electrocatalyst and ionomeric materials. In this work, the synthesis of a novel composite material that combines both components-ionomer and electrocatalyst is presented. This composite material preserves both ionic and electronic conductivities, making this a unique material for fuel cells and other electrochemical devices.