1. College of Chemistry and Molecular Sciences Hubei Key Laboratory of Electrochemical Power Sources Wuhan University Wuhan 430072 P. R. China
2. Department of Physics City University of Hong Kong Hong Kong 999077 P. R. China
3. College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 P. R. China
4. X‐ray Science Division Argonne National Laboratory Lemont IL 60439 USA
5. Shenzhen Research Institution City University of Hong Kong Shenzhen 518057 P. R. China