1. Key Laboratory of Engineering Dielectric and Applications (Ministry of Education)School of Electrical and Electronic EngineeringHarbin University of Science and Technology Harbin 150080 P. R. China
2. State Key Laboratory of Silicon MaterialsKey Laboratory of Adv. Mater. and Applications for Batteries of Zhejiang Province, and Department of Materials Science and EngineeringZhejiang University Hangzhou 310027 P. R. China