State-of-the-art polymer electrolyte membrane water electrolyzers (PEMWEs) are assembled via sandwiching a catalyst coated membrane (CCM) between porous transport layers (PTLs). In this work we investigate electrodes deposited directly on PTLs. Together with the novel fabrication technique ‘direct membrane deposition’ (DMD, Fig 1a-c) - already successfully tested for PEM fuel cells [1,2] – this approach is supposed to lead to high performance MEAs for PEMWE. In DMD the fuel cell is assembled as two half-cells with the gas diffusion layers (GDLs) serving as the base for directly depositing the catalyst and the membrane layer. With this technique contact resistances and mass transport in PEM fuel cells were shown to be substantially improved and a reduction of the noble metal loading was enabled [3].However for the application of DMD a smooth and crack-free electrode surface is required [4]. Since state-of-the-art PTLs like Titanium fiber or powder sinter materials at the anodic side exhibit relatively large pores compared to the size of catalyst particles, the fabrication of a smooth catalyst layer on top of the PTL is the first step to establish the DMD method for PEMWEs (Fig. 1d). In this work we present our latest results on this novel topic and show current challenges and perspectives.

References

[1] M. Klingele et al.: Journal of Materials Chemistry A 3 (2015) 11239 - 11245.

[2] S. Vierrath et al.: Journal of Power Sources 326 (2016) 170 - 175.

[3] M. Breitwieser et al.: Electrochemistry Communications 60 (2015) 168 - 171.

[4] M. Breitwieser et al.: Journal of Power Sources 351 (2015) 145-150.