Understanding the in-plane electron transport in low noble metal proton exchange membrane water electrolyser

Reducing noble metal loading in membrane electrode assembly (MEA) can lower the cost of proton exchange membrane (PEM) water electrolyser, but it always leads to performance decline. In-plane conductivity of catalyst layer is mentioned very critical to the cell performance, and it is necessary to fully understand the role of planar electron transportation of catalyst layer. Herein, a bilayer cathode which consists of catalyst layer and planar electron conductive layer is developed to investigate the role of in-plane electron transportation. The additional planar electron conductive layer can significantly improve the performance of the cathode under low noble metal loading. The ohmic polarization as well as the active overpotential are reduced. The results highlight the benefit of bilayer structure and provide a method for enhancing the performance even though the catalyst layer is less homogeneous. Moreover, it can be also used to guide the design of cost-effective anode. • Additional electron transport layer was added. • Bilayer electrode shows a significant performance enhancement. • Bilayer structure can improve cell performance when catalyst layer is less homogeneous.