Durability study of KOH doped polybenzimidazole membrane for air-breathing alkaline direct ethanol fuel cell

摘要

Recently, KOH doped polybenzimidazole (PBI/KOH) membrane has been reported as polymer electrolyte membrane for alkaline direct alcohol fuel cell (ADAFC), but little is known about its durability for ADAFC application. In this paper, the durability of PBI/KOH membrane for air-breathing alkaline direct ethanol fuel cell (ADEFC) is evaluated by means of ex situ and in situ tests. In the case of ex situ durability test, the ionic conductivity of PBI/KOH degrades from initial 0.023 S cmv~(-1) to 0.01 Scm~(-1) after 100 h, and the degrading rate was 1.3 x 10~(-4)Scm~(-1) h~(-1). As for in situ test, Pt-free air-breathing ADEFC with PBI/KOH membrane can output a peak power density of 16 mW cm~(-2) at 60 C. Moreover, it can stably operate for 336 h above 0.3 V. In addition, the interaction between KOH and PB1 matrix is also explored by density functional theory study.