1. Beijing Key Laboratory of Environmental Science and Engineering; School of Material Science & Engineering; Beijing Institute of Technology; Beijing 100081 P. R. China
2. Collaborative Innovation Center of Electric Vehicles in Beijing; Beijing 100081 P. R. China
3. Chemical Science and Engineering Division; Argonne National Laboratory; 9700 S. Cass Avenue Lemont IL 60439 USA
4. Department of Materials Science and Engineering; Michigan Technological University; 1400 Townsend Drive Houghton MI 49931 USA
5. X-ray Science Division; Argonne National Laboratory; Argonne IL 60439 USA
6. Electron Microscopy Center; Material Science Division; Argonne National Laboratory; 9700 S. Cass Avenue Lemont IL 60439 USA