Scalable synthesis of a cost-effective NiFeCuComedium-entropy alloy aerogel with lattice distortion and dynamic surface self-reconstruction for efficient water electrolysis

The rational design of medium-entropy alloy aerogels (MEAA) with tailored electronic structures efficiently addresses the sluggish kinetics of the oxygen evolution reaction (OER). Here, we report a scalable synthesis of an all-non-precious metal NiFeCuCo MEAA featuring a three-dimensional interconnected “pearl-like” structure and a high BET-specific surface area (106.41 m2·g− 1). NiFeCuCo MEAA is dominated by FeNi alloys with embedded Cu and Co atoms, inducing significant lattice distortions and atomic disorder. This entropy-driven engineering optimizes the electronic structure and enhances intrinsic catalytic activity. The scalable synthesis achieves a yield of 7.2 ± 0.3 g per batch, highlighting its industrial scalability. The NiFeCuCo MEAA demonstrates exceptional OER performance with a 200 mV overpotential at 10 mA·cm− 2, and a Tafel slope of 48.86 mV·dec− 1. In-situ Raman spectroscopy reveals surface self-reconstruction to NiOOH during operation, which enhances catalytic performance and protects the internal structure against corrosion, ensuring high durability. Density functional theory calculations confirm that Ni-site–dominated electronic structure optimization reduces the binding energy of *O, which improves the OER activity. When NiFeCuCo MEAA is integrated at the anode in an anion-exchange membrane water electrolyzer, the current density is up to 1.35 A·cm− 2, with a cell efficiency of 79.8% and a stable operation of 100 h.