Epoxides cross-linked hexafluoropropylidene polybenzimidazole membranes for application as high temperature proton exchange membranes. (1st April 2015)

• Record Type: Journal Article
• Authors: Yang, Jingshuai; Xu, Yixin; Liu, Peipei; Gao, Liping; Che, Quantong; He, Ronghuan
• Is Part Of: Electrochimica acta. Volume 160(2015)
• Page Start: 281
• Page End: 287
• Publication Date: 2015-04-01
• Subjects: crosslinking -- polybenzimidazole -- mechanical strength -- high temperature -- fuel cell; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2015.01.094
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Covalently cross-linked hexafluoropropylidene polybenzimidazole (F6 PBI) was prepared and used to fabricate high temperature proton exchange membranes with enhanced mechanical strength against thermoplastic distortion. Three different epoxides, i.e. bisphenol A diglycidyl ether (R1 ), bisphenol A propoxylate diglycidyl ether (R2 ) and poly(ethylene glycol) diglycidyl ether (R3 ), were chosen as the cross-linkers to investigate the influence of their structures on the properties of the cross-linked F6 PBI membranes. All the cross-linked F6 PBI membranes displayed excellent stability towards the radical oxidation. Comparing with the pure F6 PBI membrane, the cross-linked F6 PBI membranes showed high acid doping level but less swelling after doping phosphoric acid at elevated temperatures. The mechanical strength at 130 °C was improved from 0.4 MPa for F6 PBI membrane to a range of 0.8–2.0 MPa for the cross-linked F6 PBI membranes with an acid doping level as high as around 14, especially for that crosslinking with the epoxide (R3 ), which has a long linear structure of alkyl ether. The proton conductivity of the cross-linked membranes was increased accordingly due to the high acid doping levels. Fuel cell tests demonstrated the technical feasibility of the acid doped cross-linked F6 PBI membranes for high temperature proton exchange membrane fuel cells.