1. Key Laboratory of Physics & Technology for Advanced Batteries (Ministry of Education); College of Physics; Jilin University; Changchun 130012 P. R. China), Fax: (+86) 431-85155126
2. State Key Laboratory of Superhard Materials; Jilin University; Changchun 130012 P. R. China
3. Elements Strategy Initiative for Catalysts and Batteries (ESICB); Kyoto University; Kyoto 615-8520 Japan