1. School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou 221116, P. R. China
2. Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Ministry of Education, Jilin University, Changchun, 130012, P. R. China
3. Institute of Applied Mathematics, Karlsruhe Institute of Technology, Eggenstein Leopoldshafen D-76344, Germany