No abstract

No abstract

An aromatic graft polymer was synthesized for a proton exchange membrane (PEM) by grafting a highly sulfonated poly­(phenylene sulfide sulfone) side chain onto a poly­(arylene ether sulfone) main chain, thus creating a phase-separated morphology with cocontinuous channels of small hydrophilic ion domains. The graft PEM with the distinct hydrophilic/hydrophobic-separated morphology showed low hydrogen permeability while maintaining high proton conductivity. Along with durable dimensional, mechanical, and thermohydrolytic stabilities, the graft PEM showed effective properties for PEM water electrolysis (PEMWE). The graft PEM afforded a PEMWE performance of 6000 mA cm–2 at 1.9 V, which was 2.1-fold higher than that of N212, and showed a durable performance without loss for 50 h at a high current density (1000 mA cm–2).

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.

Developing a high‐performance anode design is important for a low‐cost proton‐exchange membrane water electrolyzer (PEMWE). In this study, an iridium nickel oxide directly coated anode (IrNiOx electrode) for high‐efficient PEMWE is reported. Five IrNiOx electrodes with different Ir‐to‐Ni ratios are developed using co‐electrodeposition. The resulting electrodes contain a thin IrNiOx layer on the carbon substrate. To develop the PEMWE incorporating IrNiOx electrode, the effect of fabrication methods, catalyst compositions, and porous transport layer are investigated. Consequently, the IrNiOx electrode prepared with 7:3 precursor solution (Ir0.5Ni0.5Ox) exhibits higher oxygen evolution reaction activity with a smaller overpotential than the electrode prepared with 10:0 precursor solution (IrOx) and the commercial IrO2. Furthermore, the performance of the PEMWE is higher with the Ir0.5Ni0.5Ox electrode than that with the sprayed electrode with commercial IrO2 nanoparticles. This enhancement is attributed to the high electrochemical surface area caused by introducing Ni in IrOx. Additionally, the performance of the directly coated Ir0.5Ni0.5Ox PEMWE is the highest reported in the literature.