title: An inorganic-organic proton exchange membrane for fuel cells with a controlled nanoscale pore structure.
abstract: Proton exchange membrane fuel cells have the potential for applications in energy conversion and energy storage, but their development has been impeded by problems with the membrane electrode assembly. Here, we demonstrate that a silicon-based inorganic-organic membrane offers a number of advantages over Nafion--the membrane widely used as a proton exchange membrane in hydrogen fuel cells--including higher proton conductivity, a lack of volumetric size change, and membrane electrode assembly construction capabilities. Key to achieving these advantages is fabricating a silicon membrane with pores with diameters of approximately 5-7 nm, adding a self-assembled molecular monolayer on the pore surface, and then capping the pores with a layer of porous silica. The silica layer reduces the diameter of the pores and ensures their hydration, resulting in a proton conductivity that is two to three orders of magnitude higher than that of Nafion at low humidity. A membrane electrode assembly constructed with this proton exchange membrane delivered an order of magnitude higher power density than that achieved previously with a dry hydrogen feed and an air-breathing cathode.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. saeedmog@illinois.edu
authors.forename: Saeed
authors.initials: S
authors.lastname: Moghaddam
authors.forename: Eakkachai
authors.initials: E
authors.lastname: Pengwang
authors.forename: Ying-Bing
authors.initials: YB
authors.lastname: Jiang
authors.forename: Armando R
authors.initials: AR
authors.lastname: Garcia
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Burnett
authors.forename: C Jeffrey
authors.initials: CJ
authors.lastname: Brinker
authors.forename: Richard I
authors.initials: RI
authors.lastname: Masel
authors.forename: Mark A
authors.initials: MA
authors.lastname: Shannon
mesh_terms: D011211:Electric Power Supplies; D006813:Humidity; D006859:Hydrogen / Q000737:chemistry; D006900:Hydroxylation; D008567:Membranes, Artificial; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D017646:Organosilicon Compounds; D010316:Particle Size; D016062:Porosity; D011522:Protons; D012821:Silanes / Q000737:chemistry; D012825:Silicon / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D008567:Membranes, Artificial; D017646:Organosilicon Compounds; D011522:Protons; D012821:Silanes; D006859:Hydrogen; C102833:(3-mercaptopropyl)trimethoxysilane; D012825:Silicon