1. State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
2. Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
3. Advanced Materials for Energy-Water Systems Center, Argonne National Laboratory, Lemont, Illinois 60439, USA
4. X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
5. Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA