Chinese Journal of Catalysis ›› 2016, Vol. 37 ›› Issue (7): 988-993.DOI: 10.1016/S1872-2067(16)62481-6

• Communication • Previous Articles     Next Articles

Cathode catalytic dependency behavior on ionomer content in direct methanol fuel cells

Zhi Longa,b, Guangrong Denga,c, Changpeng Liua,d, Junjie Gea,d, Wei Xinga,d, Shuhua Mab   

  1. a. State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China;
    b. Shandong Provincial Key Laboratory of Fluorine Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, Shandong, China;
    c. University of Chinese Academy of Sciences, Beijing 100049, China;
    d. Laboratory of Advanced Power Sources, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China
  • Received:2016-03-29 Revised:2016-05-03 Online:2016-06-17 Published:2016-06-17
  • Contact: Wei Xing, Shuhua Ma
  • Supported by:

    This work was supported by the National Basic Research Program of China (973 Program, 2012CB932800), the National Natural Science Foundation of China (21433003, 21373199), and the Science & Technology Research Programs of Jilin Province (20150101066JC, 20160622037JC).

Abstract:

Cathode catalyst layers (CLs) with varying ionomer (Nafion) contents were prepared and the direct methanol fuel cell structure and catalytic behavior were investigated as a function of ionomer content. CL roughness and thickness increased with increasing Nafion content. Contact angle measurements determined that CL hydrophilicity also increased as a function of Nafion content. Poor bonding between the CL, microporous layer, and the proton exchange membrane was obtained when the ionomer content was too low. The electrochemical surface areas (ESAs) were found to increase with increasing Nafion content before reaching an asymptote at elevated loading levels. However, upon increasing the ionomer content above 30 wt.%, the water and oxygen mass transfer properties were difficult to control. Considering the above conditions, N30 (30 wt.% Nafion) was found to be the optimal level to effectively extend the three-phase boundaries and enhance cell performance.

Key words: Direct methanol fuel cells, Catalyst layer, Nafion, Cathode, Ionomer