Sulfonated Poly (Phthalazinone Ether Sulfone Ketone)/Poly (Vinylidene Fluoride) Blend Membranes for Direct Methanol Fuel Cell

Sulfonated poly(phthalazinone ether sulfone ketone)/poly(vinylidene fluoride) blend membranes for direct methanol fuel cell

Ming Wang, Hong Zhu*, Ting Zhao, Yu-Guo Yang

Department of Chemistry, School of Science, Beijing Jiaotong University, Beijing 100044, China

*E-mail: hzhu@bjtu.edu.cn;  Tel: 86-10-51684001; Fax: 86-10-82161887

Direct methanol fuel cells (DMFCs) have attracted much interest as a candidate power source for portable devices. Yet they have major technical drawbacks, i.e., slow oxidation kinetics of methanol and high methanol crossover from anode to cathode. In particular, high methanol permeation through Nafion membrane not only wastes fuel but also causes performance loss. Therefore, intense efforts are focused to find membrane with lower methanol permeability and excellent proton conductivity..

So far, new membrane alternatives to Nafion membrane have been investigated, including sulfonated poly(ether ether ketone)(SPEEK), sulfonated polysulfones, sulfonated poly(ether sulfones) and so on. Compared with Nafion membrane, the hydrocarbon membranes have poor proton conductivity and lower methanol permeability. To achieve high proton conductivity, hydrocarbon membranes with high sulfonated degree are used. Sulfonated poly(phthalazinone ether sulfone ketone) (SPPESK) is a novel hydrocarbon polymer. SPPESK with high sulfonated degree has high proton conductivity and poor mechanical property. For the sake of keeping a certain mechanical strength, polymer blend was taken to reduce swelling degree. Poly(vinylidene fluoride) (PVDF) is considered as the structural component by virtue of its good methanol resistance as well as its excellent thermal stability. In this study, SPPESK material is blended with PVDF.

SPPESK/PVDF blend membranes with different contents of PVDF were prepared by casting process. Scanning electron microscopy (SEM), water uptake, swelling degree, proton conductivity, methanol permeability and longevity of blend membranes were investigated. SEM indicated that phase separation existed in blend membranes. Water uptake, swelling degree, proton conductivity and methanol permeability collectively decreased as the content of PVDF increased. Though the proton conductivity of blend membranes was decreased to a certain extent, their methanol resistant performance remarkably enhances. Fenton experiments indicated that with the content of PVDF increasing, the expended time that membrane became a little brittle increased. That is to say, the longevity of blend membranes was extended due to the addition of PVDF. Based on the preliminary results, it can be concluded that the polymer blends of SPEEK/PVDF can be used as a candidate membrane materials for DMFC applications.     

Acknowledgements

The authors gratefully acknowledge the financial support from the National High Technology Research and Development Program of China (863 Program, No. 2006AA03Z226), The National Science Foundation of China (Key Program No. 20636060), International S&T Cooperation Program of China (No. 2006DFA61240) and the Natural Science Foundation of Beijing (No. 2073031).

References

[1] C. Manea, M. Mulder, J. Membr. Sci., 206, 443-453 (2006)

[2] H. L. Wu, C.C. M. Ma, F. Y. Liu, et al., Eur. Polym. J., 42,1688-1695 (2006)

[3] S. Z. Ren, G.. Q. Sun, C. N. Li, et al., Mater. Lett., 60, 44-47 (2006)

Author information

Ming Wang, Master candidate; Mailing address: Department of Chemistry, School of Science, Beijing Jiaotong University, Beijing 100044, China; E-mail: 06122083@bjtu.edu.cn; Tel: 86-10-51684001; Fax: 86-10-82161887.

Hong Zhu,Doctor; Professor; Mailing address: Department of Chemistry, School of Science, Beijing Jiaotong University, Beijing 100044, China; E-mail: hzhu@bjtu.edu.cn; Tel: 86-10-51684001; Fax: 86-10-82161887.

Ting Zhao, Master candidate; Mailing address: Department of Chemistry, School of Science, Beijing Jiaotong University, Beijing 100044, China; E-mail: 06122082@bjtu.edu.cn; Tel: 86-10-51684001; Fax: 86-10-82161887.

Yu-Guo Yang, Doctor; Associate Professor; Mailing address: Department of Chemistry, School of Science, Beijing Jiaotong University, Beijing 100044, China; E-mail: ygyang@bjtu.edu.cn; Tel: 86-10-51684001; Fax: 86-10-82161887.

Ming Wang

Description of Education

BS, 2005--Shandong University of Technology, Zibo, Shandong--Proton exchange membrane