1. Division
of Physics and Applied Physics, School of Physical and Mathematical
Sciences, Nanyang Technological University, Singapore 637371, Singapore
2. State
Key Laboratory of Silicon Materials, Key Laboratory of Advanced Materials
and Applications for Batteries of Zhejiang Province, and Department
of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
3. School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore