1. Energy Research Institute @NTU (ERI@N), Nanyang Technological University, Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, 637553, Singapore
2. School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798, Singapore
3. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
4. Faculty of Materials and Energy, Southwest University, Chongqing 400715, China