Improvement in high temperature proton exchange membrane fuel cells cathode performance with ammonium carbonate

• Published in: Journal of power sources 2005-03, Vol.141 (2), p.250-257
• Main Authors: Song, Ying, Wei, Yu, Xu, Hui, Williams, Minkmas, Liu, Yuxiu, Bonville, Leonard J., Russell Kunz, H., Fenton, James M.
• Format: Article
• Language: English
• Subjects: Ammonium carbonate; Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; High temperature; Nafion; Pore-former; Proton exchange membrane fuel cell
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2004.09.021

Proton exchange membrane (PEM) fuel cells with optimized cathode structures can provide high performance at higher temperature (120 °C). A “pore-forming” material, ammonium carbonate, applied in the unsupported Pt cathode catalyst layer of a high temperature membrane electrode assembly enhanced the catalyst activity and minimized the mass-transport limitations. The ammonium carbonate amount and Nafion ® loading in the cathode were optimized for performance at two conditions: 80 °C cell temperature with 100% anode/75% cathode R.H. and 120 °C cell temperature with 35% anode/35% cathode R.H., both under ambient pressure. A cell with 20 wt.% ammonium carbonate and 20 wt.% Nafion ® operating at 80 °C and 120 °C presented the maximum cell performance. Hydrogen/air cell voltages at a current density of 400 mA cm −2 using the Ionomem/UConn membrane as the electrolyte with a cathode platinum loading of 0.5 mg cm −2 were 0.70 V and 0.57 V at the two conditions, respectively. This was a 19% cell voltage increase over a cathode without the “pore-forming” ammonium carbonate at the 120 °C operating condition.