History of Early PEM Development

Solid polymer acid electrolytes were first developed for fuel cell applications in the late 1950 s by the General Electric Company (GE), which initiated a program to develop membrane cells and electrolyzers. The first membranes developed by GE for fuel cell applications were made by the condensation of phenolsulfonic acid and formaldehyde. These membranes were found to be brittle, prone to cracking when dried, and rapidly hydrolyzed 

In order to address the stability problem observed, GE developed the S Series of membranes which were developed from the homopolymers of a.p.p- 

Perfluorosulfonate ionomer (PFSI) - Dow Cemical Company Fig. 1.5. Chemical structures of perfluorosulfonate ionomer materials. 

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