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 cm2 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.