1. Department of Mechanical Engineering, Tufts University, Medford, Massachusetts 02155, United States
2. Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
3. Department of Chemical & Biomolecular Engineering, University of California Irvine; National Fuel Cell Research Center, Irvine, California 92697, United States
4. Ionic Materials, Inc., Woburn, Massachusetts 01801, United States
5. Department of Chemical & Biological Engineering, Tufts University, Medford, Massachusetts 02155, United States