1. State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi’an 710072, P. R. China.
2. Leibniz Institute for Solid State and Materials Research (IFW) Dresden e.V. Helmholtzstr 20, Dresden 01069, Germany.
3. School of Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
4. School of Physical Science and Technology, Jiangsu Key Laboratory of Thin Films, Center for Energy Conversion Materials and Physics (CECMP), Soochow University, Suzhou 215006, P. R. China.
5. Department of Inorganic Chemistry, Technische Universität Dresden, Bergstrasse 66, Dresden 01062, Germany.
6. Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, P. R. China.
7. John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.