Production of the porous transport layer based on stainless steel felt for anion exchange membrane water electrolysis

Anion Exchange Membrane Water Electrolysis (AEMWE), is considered as one of the most promising available green production technologies, due to its overall low cost and high performance. Porous transport layers (PTLs), are much important for the performance of AEMWE, providing effective electron transport channels and efficient removal of gas products. Stainless steel-based PTLs have been demonstrated to achieve better performance at a reduced cost compared to routine nickel-base PTLs. Herein, PTLs based on 316L stainless-steel with varying parameters (fiber diameter, thickness and porosity) are investigated from a production perspective to identify the optimal design. How these parameters impact the performance of water electrolysis is further analyzed by separating the ohmic, activation and mass transfer overpotentials. The results indicate that the fiber diameter and porosity are of greater significance than the thickness. The fiber diameter exerts the most substantial effect on the performance and polarization distribution for AEMWE. The PTL with a fiber diameter of 12 μm performs best, representing a compromise among electrochemical reaction, electrical conductivity and mass transfer. Furthermore, the ohmic resistance and mass transfer process are the main factors influencing the observed differences in performance with varying thicknesses and porosities. The optimum thickness and porosity are subsequently identified as 0.3 mm and 72 %, respectively. In conclusion, this study presents an optimal structure for the anode PTL based on 316L stainless-steel felts in AEMWE, achieving the current density of 2.760 A/cm 2 at 2.0 V.