1. Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, San Diego, California 92093, United States
2. Plug Power, Latham, New York 12110, United States
3. Materials Science and Engineering Program, University of California San Diego, La Jolla, San Diego, California 92093, United States
4. Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States