1. Department of Physics City University of Hong Kong Hong Kong 999077 P. R. China
2. Center of Hydrogen Science Shanghai Jiao Tong University Shanghai 200240 P. R. China
3. Innovation Center for Future Materials Zhangjiang Institute for Advanced Study Shanghai Jiao Tong University Shanghai 201203 P. R. China
4. The State Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P. R. China
5. Department of Chemistry and Chemical Biology Harvard University Cambridge MA 02138 USA
6. School of Chemical Engineering and Light Industry Guangdong University of Technology Guangzhou 510006 P. R. China
7. X‐Ray Science Division Argonne National Laboratory Argonne IL 60439 USA
8. College of Physics and Materials Science Tianjin Normal University Tianjin 300387 P. R. China
9. School of Materials Science and Engineering Tianjin University Tianjin 300072 P. R. China
10. School of Material Science and Engineering Nanjing University of Science and Technology Nanjing 210094 P. R. China
11. Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
12. Shenzhen Research Institute City University of Hong Kong Shenzhen 518057 P. R. China
13. Center for Neutron Scattering City University of Hong Kong Hong Kong 999077 P. R. China
14. Hong Kong Institute for Clean Energy City University of Hong Kong Hong Kong 999077 P. R. China