Enhanced performance and durability of composite membranes containing anatase titanium oxide for fuel cells operating under low relative humidity

In this work, sulfonated diblock copolymers (SDBCs) were prepared by polycondensation of sulfonated poly(ether-ether-ketone) (SPEEK) and hydrophobic oligomer, which were combined with sintered anatase titanium oxide (S-An-TiO₂) to create a hybrid membrane for apply in proton exchange membrane fuel cells (PEMFCs) operating with low relative humidity (RH). Then, a series of composite membranes (SDBC/S-An-TiO₂) were prepared by varying the wt% of S-An-TiO₂ blended with SDBC. The results showed that appropriate quantity (ie, 15 wt%) of S-An-TiO₂ can significantly improve the proton conductivity and physiochemical properties of prepared composite membrane, as well as the PEMFC performance and durability under 20% RH. The 1.5 wt% of SDBC/S-An-TiO₂ offers high current output, power output, and durability values at 60°C under 20% RH, which are 0.207 A cm⁻², 0.074 W cm⁻² and over 90 hours, respectively. These results can be attributed to the good interfacial compatibility between S-An-TiO₂ and SDBC.