Porous polybenzimidazole membranes with excellent chemical stability and ion conductivity for direct borohydride fuel cells

Porous membranes based on polybenzimidazole (PBI) are firstly introduced in direct borohydride fuel cell application (DBFC). Membranes with different thicknesses and porosity are successfully fabricated via water vapor phase inversion process. The prepared membranes show excellent ion conductivity and chemical stability under DBFC operating condition. Compare with Nafion 115, the prepared membranes show higher ion conductivity, as a result, much higher peak power density. No weight loss is observed after immersing the prepared membranes in a 3 M NaOH solution for 30 days, indicating the excellent chemical stability of porous PBI membranes. And the DBFC cells assembled with prepared membranes could discharge at 200 mA cm(-2) for more than 250 h without voltage decay, which is the longest time reported by far. This work provides a totally new idea for fabricating versatile DBFC membranes. (C) 2015 Elsevier B.V. All rights reserved.