REMRSEC Advanced Membrane Research (IRG2) Highlights

The Advanced Membrane Interdisciplinary Research Group (Advanced Membrane IRG) concentrates on advanced membrane materials research for use in fuel cells technology, batteries, and other renewable energy applications. The Advanced Membrane IRG studies polymers, ionic solids, and hybrid systems. Since, ionic transport is the “weak link” in electrochemical energy storage or conversion systems, the Advanced Membrane IRG research focuses on the intelligent design of novel transport membranes with highly optimized properties. The Advanced Membrane IRG also focuses on nanostructured materials, which show great promise for improved ionic transport and stability.

Click here to view REMRSEC IRG2 publications.

2012 Highlights

  •  REMRSEC REU summer program Colordao School of Mines

    Enhanced Proton Conduction in Ceramics

    Annette Bunge, Ryan O’Hayre, Jianhua Tong, Jason Fish, Dan Clark
    We have developed a novel synthetic method to partially modify the grain boundaries of a solid oxide membrane with metal inclusions to increase ionic conductivity (protons). See highlight for more information.
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  •  REMRSEC REU summer program Colordao School of Mines

    Electrochromics For Smart Windows

    Colin Wolden, Chi-Ping Li, Rob Tennet, and Anne Dillon
    “Smart windows” integrating an electrochromic device can substantially mitigate building energy losses through interactive control of solar irradiation.
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2011 Highlights

  •  REMRSEC Novel Ceramic/Organic Ionomers

    Novel Ceramic/Organic Ionomers

    Greg Schlichting, Andrew Herring
    Phosphonic acid based materials have generated substantial interest for PEM fuel cells, but up until now have all shown disappointing proton conductivities. We have produced a novel zirconium vinyl phosphonate/vinyl phosphonic acid copolymer that exceeds the proton conductivity of all other phosphonic acid based polymers. Pulsed gradient NMR experiments have shown proton transport proceeds through a unique mechanism involving the rearrangement of the Zr-O bonding. This structural mechanism for proton diffusion requires little or no water which enables high proton conductivity, c.a. 50 mS cm-1 at 50% RH.
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  • REMRSEC Dynamic Measurements of Polymer Electrolytes

    Dynamic Measurements of Polymer Electrolytes

    Yuan Liu, Andrew Herring
    The performance of  polymer electrolyte membrane fuel cells (PEMFCs) varies dramatically with environmental conditions such as temperature or relative humidity.  We have developed a unique capability to dynamically measure the morphological changes in these materials with nanoscale precision using small angle X-ray scattering (SAXS) in collaboration with the  Advanced Photon Source.  These measurements are interpreted using the unified fit model, providing unprecedented insight into the evolution of these materials in well-defined environments.
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  •  REMRSEC Novel Transport Mechanisms in Conducting Ceramics

    Novel Transport Mechanisms in Conducting Ceramics

    Michael Sanders, Robert Kee, Ryan O’Hayre
    Our team has discovered an unusual multi-species defect-transport coupling process occurring in these materials when employed in gas permeation applications. Simultaneous mixed conduction of protons (OHO•), oxygen vacancies (V••), and electronic defects (electrons or holes) enables the separation of oxygen, hydrogen or steam and, remarkably, can even force any one of these species to be transported against its concentration gradient (uphill diffusion). We believe that these materials can be used to great advantage in applications such as membrane reactors for chemical processing.
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  •  REMRSEC Advanced Synthesis of Proton Conducting Ceramics

    Advanced Synthesis of Proton Conducting Ceramics

    Stefan Nikodemiski, Dan Clark, Jianhua Tong, Ryan O’Hayre
    Proton-conducting perovskites are enabling materials for intermediate temperature SOFCs and electrolyzers.  Our team has demonstrated the benefits of oxide-based additives to promote grain growth during synthesis. A comprehensive screening revealed that oxides with a +2 transition metal cation  dramatically enhance the sinterability of proton conducting perovskites. This work has culminated in the scientific understanding and commercial development of a new synthesis methodology, solid-state reactive sintering (SSRS),  which has been adopted by our industrial partner (Coorstek) for fuel cell and ionic membrane applications.
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  •  REMRSEC Simulation of Proton Transport in PEM Fuel Cells

    Simulation of Proton Transport in PEM Fuel Cells

    Steve Tse, Andrew Herring
    The complexity of polymer electrolytes has constrained theoretical attempts to model these systems.  Classical molecular dynamics (MD) simulations cannot study proton transfer, while ab initio techniques are too expensive. We are using multistate empirical valence bond theory (MS-EVB) as a novel approach to study proton transfer within PFSA membranes.  With MS-EVB, accurate calculation of the potential energy surface of proton transfer is enabled at time and length scales that cannot be achieved by any other methods.  We are able to extract macroscopic transport properties such as diffusion constants and conductivity that may be tested by experimental measurements.
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  •  REMRSEC Poisson-Boltzmann Model of Nanoionic Composites

    Poisson-Boltzmann Model of Nanoionic Composites

    Jason Fish, Chi-Ping Li, Joseph Fehribach, Colin Wolden,
    Ryan O’Hayre, Annette Bunge, and Christopher Goodyer

    Nanoionic composites have the potential to dramatically enhance the ionic conductivity of solid state electrolytes that are critical to  numerous devices including fuel cells, electrochromic windows, and thin film batteries.

    We have developed a fundamental model of these materials, detailing the nature of the space charge layers that surround individual particles as well accounting for their interactions with neighboring particles. This allows us to rigorously explore the impact of nanoparticle arrangement in the matrix, providing a reliable and versatile tool for experimentalists developing nanoionic materials.
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2010 Highlights

  •  Epitaxial Core-Shell Nanowires

    Mesoporous, Nanoparticle-based Electrochromic Films

    Chi-ping Li, Robert Tenent, Anne Dillon, Colin Wolden
    WO3 nanoparticles (NPs) in the size range 15 – 35 nm were fabricated using hot-wire chemical vapor deposition (HWCVD). The size and shape could be controlled by the oxidizing nature of HWCVD environment. These NPs were subsequently suspended in green solvents (water, alcohol), and used to produce mesoporous electrochromic films by ultrasonic spray deposition (USD).
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  •  REMRSEC Polymer/Nanoparticle Films

    Polymer/Nanoparticle Films

    Melissa Kern, Nathan Bade, Matt Liberatore and Steve Boyes
    The most successful organic photovoltaic devices (OPVs) use a bulk heterojunction design. This is a nanostructured blend of a light absorbing organic (often a polymer) electron donor and an electron acceptor (often a fullerene). The blend is necessary because of the short diffusion length of optically excited excitons in the organic and the requirement that an exciton must reach an interface before de-exciting if it is to decompose into an electron and hole which can be collected. The morphology of the donor/acceptor blend is critical to charge generation and to carrier collection.
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2009 Highlights

  •  Epitaxial Core-Shell Nanowires

    Proton Transport in Ionic Space Charge Regions 
    A. Deml, R. O’Hayre, A. Bunge, W. Medlin, N. Sammes,
    R. Kee
    Renewable Energy MRSEC

    The devices in computers that are used to switch electrical current on and off are field effect transistors. In these devices electric fields are used to switch the current. Researchers in the Renewable Energy MRSEC at the Colorado School of Mines have made the first “field effect transistor” that switches currents of charged atoms, called ionic currents. In this prototype device the atoms are positively charged hydrogen (protons) and the transport medium is a material called Nafion. Potential applications of this novel device include electrochemical switches and ionic logic components. Instead of nano-electronics one can now think about “nano-ionics”.
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2008 Highlights

  •  Proton Transport in Inorganic/Polymer Membranes

    Proton Transport in Inorganic/Polymer Membranes
    A. Herring, D. Knauss, A. Dillon, J. Turner
    Renewable Energy MRSEC

    Researchers at the Colorado School of Mines and their colleagues are synthesizing new polymers which bring together super acidic metal oxides with organic monomers. The result is a new material hybrid which can transport protons at high temperatures without using much water. These materials will allow fuel cells to be designed for use in hotter and drier environments.
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  •  Proton Transport in Metal/Ceramic Membranes

    Proton Transport in Metal/Ceramic Membranes
    R. O’Hayre, N. Sammes, M. Lusk, W. Medlin, A. Bunge Renewable Energy MRSEC

    Researchers at the Colorado School of Mines and their colleagues are developing a composite material to vastly increase the rate of proton conduction through ceramics. Nano sized metal particles, embedded within a ceramic, generate an electronic space charge layer at metal/ceramic interfaces. Based on the theory that protons move quickly through such regions, composite materials have been designed in which the space charge layers are interconnected. This results in an entirely new form of proton conductor which could be a boon to fuel cell technology.
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