1. Guangzhou Nanyang Polytechnic College Guangzhou 510000 P. R. China
2. School of Materials and Energy Guangdong University of Technology Guangzhou 510006 P. R. China
3. Wanjin New Energy Research Institute Shunde 528300 P. R. China
4. Guangdong Zhuhai Supervision Testing Institute of Quality and Metrology Zhuhai 519000 P. R. China