1. Faculty of Material Science and Chemistry China University of Geosciences Wuhan 430074 China
2. School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
3. Guangdong Provincial Key Laboratory of Energy Materials for Electric Power Southern University of Science and Technology Shenzhen 518055 Guangdong China
4. Sino-Singapore International Joint Research Institute (SSIJRI) Guangzhou 510700 China