Combined composite membrane and gas diffusion oxygen electrode toward alkaline electrolyzer for efficient electrocatalytic water splitting

Efficient hydrogen production through water splitting is vital for advancing clean energy technologies. This work presents the design and fabrication of a novel composite membrane integrated into a zero-gap alkaline electrolyzer with a gas diffusion electrode, aiming to address energy efficiency challenges and gas bubble hindrance. The composite membrane, denoted NiₓFeᵧ-LDH@PVA, features a unique polymer network embedding nickel-iron layered double hydroxides (Ni x Fe y -LDH) grafted onto polyvinyl alcohol (PVA), as a multichannel transmission medium. Ni x Fe y -LDH@PVA composite membrane has high ionic conductivity, mechanical stretchability, wettability, and high ion adsorption. Meanwhile, an optimized alkaline electrolyzer structure improves the ion transport efficiency from the cathode and reduces the resistance to bubble release. An alkaline electrolyzer is assembled using a nickel mesh (NM) electrode for overall water splitting. Experimental results demonstrate that the alkaline electrolyzer utilizing the NM|Ni₃Fe₁-LDH@PVA|NM configuration achieves a current density of 590 mA cm −2  at a cell voltage of 2.0 V in the 90 °C and exhibits robust stability, operating for over 200 h. This work provides a meaningful strategy using composite membranes as a substitute for traditional separators (asbestos, textile cloth, polyphenylene sulfide, etc.) to promote the development of the conventional alkaline electrolyzer.