1. Department of Materials Science and Engineering, National University of Singapore, Singapore 117579, Singapore.
2. MOE Key Laboratory of Low-Grade Energy Utilization Technologies and Systems, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, P. R. China.
3. Singapore Institute of Manufacturing Technology, Singapore 637662, Singapore.
4. Harbin Institute of Technology, University Town of Shenzhen, Shenzhen 518055, P. R. China.
5. NUS Research Institute, No 16 South Huashan Road, Liangjiang New Area, Chongqing, China.