1. National Synchrotron Radiation Laboratory; CAS Hefei Science Center, Hefei National Laboratory for Physical Science at the Microscale; School of Chemistry; University of Science and Technology of China; Hefei Anhui 230029 PR China
2. State Key Laboratory of Silicon Materials; Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province; Department of Materials Science and Engineering; Zhejiang University; Hangzhou Zhejiang 310027 PR China
3. Department of Materials Science and Nano Engineering; Rice University; Houston TX 77005 USA