Effect of pore structures in nickel-based porous transport layers for high-performance and durable anion-exchange membrane water electrolysis

Investigation of the anode porous transport layer (PTL) is crucial for the commercialization of anion-exchange membrane water electrolysis (AEMWE). Recently, nickel foam (Ni-foam) has been employed as an alternative to the conventional titanium-based PTL (Ti-felt) and strategies to improve its performance and durability have been developed. However, few studies have investigated the effect of pore structures in Ni-foam and the applications of other Ni-based PTLs have not been reported. In this study, two Ni-based PTLs with different pore structures, Ni-foam and nickel felt (Ni-felt), were applied and investigated to attain a suitable microstructure in the PTL. The AEMWEs with the optimized Ni-foam and Ni-felt showed superior performance and durability than that with the conventional Ti-felt. In particular, the application of Ni-foam as an anode PTL resulted in higher performance than that of Ni-felt, which is attributed to the reduced mass transfer resistance caused by the interconnected pore structure. The Ni-foam PTL optimized in this study can be an efficient alternative to the conventional Ti-felt PTL because it can facilitate the enhanced AEMWE performance and durability.