Development of Ni-coated high-conductivity Cu porous transport layers with enhanced corrosion stability for efficient alkaline water electrolysis

Abstract

High operational current density is essential to achieve cost-effective water electrolysis. To meet this requirement, minimizing both ohmic and mass transport resistances within the electrolyzer is crucial. In particular, the porous transport layers (PTLs) play a pivotal role by providing efficient electron conduction paths and an optimized pore structure that enhances mass transport while reducing interfacial contact resistance. While previous studies focus on tailoring PTLs pore structures, improving electrical conductivity without compromising corrosion resistance remains a significant challenge. Here, we develop Ni-coated Cu PTLs that combine the corrosion resistance of nickel with the high electrical conductivity of copper. The optimized Ni75Cu25 PTLs maintains stable performance and preserves its initial activity during long-term operation at 1.5 A/cm2 for 600 h with commercial Zirfon separators. The efficiency advantage of the Ni75Cu25 PTL is consistently observed even with the thinner Z85_300 mu m separator, exhibiting a lower cell voltage of 2.17 Vat 4 A/cm2and a reduced high frequency resistance (0.088 Omega cm2). These results demonstrate that the Ni-coated Cu structure enables both high-current-density operation and extended durability in alkaline water electrolysis, providing a foundation for next-generation PTLs that enhance hydrogen production efficiency and long-term sustainability.