1. Laboratory for Integrated Technology of “Urban and Rural Mines” Exploitation, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, No. 2 Nengyuan Road, Wushan, Tianhe District, Guangzhou, Guangdong 510640, P. R. China
2. Key Laboratory of Renewable Energy, Chinese Academy of Sciences, Beijing, P. R. China
3. Guangdong Provincial Key Laboratory of New and Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, P. R. China
4. University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, P. R. China