High-entropy alloy enables multi-path electron synergism and lattice oxygen activation for enhanced oxygen evolution activity

Abstract

Electrocatalytic oxygen evolution reaction (OER) is key to several energy technologies but suffers from low activity. Leveraging the lattice oxygen activation mechanism (LOM) is a strategy for boosting its activity. However, this approach faces significant thermodynamic challenges, requiring high-valent oxidation of metal ions without compromising their stability. We reveal that high-entropy alloys (HEAs) can efficiently activate the LOM through synergistic multi-path electron transfer. Specifically, the oxidation of nickel is enhanced by this electron transfer, aided by the integration of weaker Co-O bonds, enabling effective LOM at the Ni-Co dual-site. These insights allow the design of a NiFeCoCrW_0.2 HEA that exhibits improved activity, achieving an overpotential of 220 mV at a current density of 10 mA cm⁻². It also demonstrates good stability, maintaining the potential with less than 5% variation over 90 days at 100 mA cm⁻² current density. This study sheds light on the synergistic effects that confer high activity in HEAs and contribute to the advancement of high-performance OER electrocatalysts.