Optimization of the Interface Between Catalyst Layer and Proton Exchange Membrane via Rolled Technique

Abstract

Optimization of the interface between the catalyst layer (CL) and the proton exchange membrane (PEM) plays an important role in performance enhancement in proton exchange membrane fuel cells (PEMFCs). Here, a rolled technique was used to optimize the PEM∣CL interface to obtain a smooth CL surface with decreased roughness from 0.347 to 0.266 μm due to the reduction of protrusions after the rolled process. Advantages of the optimized PEM∣CL interface formed after decal transfer method were carefully evaluated. First, the internal resistance of the rolled CL is significantly reduced from 61.5 to 47.5 mΩ cm2@2000 mA cm−2, which is ascribed to the higher contact area between CL and PEM. Meanwhile, owning to the alleviation of liquid water accumulation at the interface, the oxygen transport resistance at no back pressure of CL dropped from 0.21 to 0.15 s cm−1. The relieved ohm polarization and mass transfer polarization promote a 28.5% increase of performance. Rolled technique with proper calendrer roll space could result in an optimized interface with well-maintained internal structural integrity of CL. However, a lower calendrer roll gap will damage the structure of CL and have a negative effect on the interface optimization.