Cathode starvation as an accelerated conditioning procedure for perfluorosulfonic acid ionomer fuel cells

Abstract

Freshly assembled proton exchange fuel cells (PEMFC) require conditioning to reach maximum power density. This process may last up to tens of hours and adds to the cost of commercial fuel cell technology. We present an accelerated conditioning procedure involving starving the cathode of oxidant. In single cells, this procedure conditions a membrane electrode assembly (MEA) within 40 min, without compromising durability. The performance and durability of MEAs conditioned using this technique are compared with US Department of Energy (DOE) and European Union (EU) harmonized protocols, and to an amperometric conditioning protocol. The time to reach peak power density using cathode starvation conditioning is <10% of the time required for DOE, EU, and amperometric protocols. Conditioned MEAs were subjected to accelerated degradation by cycling the cell voltage between 0.6 V and open-circuit voltage under low relative humidity. Degradation was found to be caused by loss of electrochemical surface area of the cathode, which in turn increases the charge transfer resistance of the MEA. MEAs conditioned using cathode starvation experienced only a 15% loss in performance; in contrast to 19, 17 and 17% losses in performance caused by the DOE, EU, and amperometric protocols, respectively.

Keywords

• PEMFC
• Fuel cell conditioning
• Perfluorosulfonic acid ionomer
• Accelerated degradation