Durability Studies on PBI Based High Temperature PEMFC

Abstract

HT-PEMFC based on phosphoric acid-doped polybenzimidazole membranes are a technology characterized by simplified construction and operation along with methanol reformers. Durability issues including acid loss, platinum sintering and carbon corrosion are recognized for both steady state and start-stop cycling operations. This work reports experimental studies on the degradation of PBI-based fuel cells operating with synthetic reformate fuel and air. Degradation stressors include elevated temperatures, pressures, current densities, and start-stop cycles. An average degradation rate of 9.3 mV/h is observed for continuous operation at 0.4 A/cm2 and 160 ˚C for 12,000 hours. High pressure (1.5 bara) operation at 170 oC and 0.8 A/cm2 shows an average degradation rate of 12.6 µV/h during a period of 2,000 hours. A start-stop test from 50 oC consisting of 240 cycles between temperatures of 165 and 175 oC and current density of 0.31 and 0.55 A/cm2 reveals a performance decay by 0.48-0.58 mV/cycle.