1. Department of Mechanical Engineering, Masdar Institute, Khalifa University of Science and Technology, P.O. Box 54224, Abu Dhabi, UAE
2. Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
3. Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
4. Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
5. International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744
Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan