1. Department of Mechanical and Materials Engineering, The University of Western Ontario, London, ON N6A 5B9, Canada
2. Department of Materials Science and Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada
3. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, P. R. China
4. Ballard Power Systems Inc., 9000 Glenlyon Parkway, Burnaby, BC V5J 5J8, Canada