1. Center for Condensed Matter SciencesNational Taiwan University Taipei 10617 Taiwan; Center of Atomic Initiative for New Materials, National Taiwan University, Taipei 10617, Taiwan
2. Department of Vehicle EngineeringNational Taipei University of Technology Taipei 10643 Taiwan
3. Department of Information and ElectronicBeijing Institute of Technology Beijing 100081 China
4. Phoenix Battery Corporation Hsinchu 30078 Taiwan