1. National and Local Joint Engineering Center for Lithium-ion Batteries and Materials Preparation Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, PR China
2. School of Materials and Energy, Yunnan University, No. 2, Green Lake North Road, Kunming 650091, PR China
3. Electron Microscopy Center, Yunnan University, No. 2, Green Lake North Road, Kunming 650091, PR China