Fluorinated membranes

Ionomeric membranes comprising (per)fluorinated, semicrystalline or amorphous, ionomeric polymers, having equivalent weight (EW) from 380 g/eq to 1,800 g/eq, which used in fuel cells, under the following conditions: membrane thickness 50 µm assembled between two electrodes catalyzed with 0.6 mg/cm Pt/C and treated with 0.7 mg/cm of Nafion®, having a 10 cm area; hydrogen and air feeding, both at the pressure of 0.25 MPa, both saturated with water at 80°C; cell temperature 75°C; for membranes formed of copolymers TFE/FC=CF-O-(CF)-SOF, give the following maximum specific power (P) values, at the indicated EW values: at EW = 670 Phigher than 0.55 Watt/cm; at EW = 830 Phigher than 0.66 Watt/cm; at EW = 1,160 Phigher than 0.50 Watt/cm; at EW = 1,600 Phigher than 0.32 Watt/cm.