1. State Key Laboratory of Power Transmission Equipment and System Security; Chongqing University; 174 Shazheng Street Shapingba District Chongqing City 400044 P. R. China
2. Department of Applied Physics; Chongqing University; 55 Daxuecheng South Road Shapingba District Chongqing City 401331 P. R. China
3. Center for Electron Microscopy; Institute for New Energy Materials and Low-Carbon Technologies; School of Materials Science and Engineering; Tianjin University of Technology; Tianjin 300384 China
4. Institute for Clean Energy and Advanced Materials; Faculty of Materials and Energy; Southwest University; Chongqing 400715 P. R. China
5. Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Electrical Power Sources; Chongqing 400715 P. R. China
6. Institute of Materials Science and Devices; Suzhou University of Science and Technology; Suzhou 215011 P. R. China