1. The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China
2. Sunwoda Electronic Co., Ltd., Shenzhen, Guangdong 518100, China
3. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China
4. HySA Infrastructure Centre of Competence, Materials Science and Manufacturing (MSM), Council for Scientific and Industrial Research (CSIR), PO Box 395, Pretoria 0001, South Africa