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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 NiFeCoCrW0.2 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.