1. Key
Laboratory of Materials for Energy Conversion, Chinese Academy of
Sciences, Department of Materials Science and Engineering, University of Science and Technology of China, No. 96 Jinzhai Road, Hefei, Anhui 230026, P. R. China
2. Beijing
National Laboratory for Condensed Matter Physics, The Institute of
Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China
3. State
Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China