Ultrafast Electrical Pulse Synthesis of Highly Active Electrocatalysts for Beyond‐Industrial‐Level Hydrogen Gas Batteries

Abstract The high reliability and proven ultra‐longevity make aqueous hydrogen gas (H 2 ) batteries ideal for large‐scale energy storage. However, the low alkaline hydrogen evolution and oxidation reaction (HER/HOR) activities of expensive platinum catalysts severely hamper their widespread applications in H 2 batteries. Here, cost‐effective, highly active electrocatalysts, with a model of ruthenium‐nickel alloy nanoparticles in ≈3 nm anchored on carbon black (RuNi/C) as an example, are developed by an ultrafast electrical pulse approach for nickel‐hydrogen gas (NiH 2 ) batteries. Having a competitive low cost of about one fifth of Pt/C benckmark, this ultrafine RuNi/C catalyst displays an ultrahigh HOR mass activity of 2.34 A mg −1 at 50 mV (vs RHE) and an ultralow HER overpotential of 19.5 mV at a current density of 10 mA cm −2 . As a result, the advanced NiH 2 battery can efficiently operate under all‐climate conditions (from −25 to +50 °C) with excellent durability. Notably, the NiH 2 cell stack achieves an energy density up to 183 Wh kg −1 and an estimated cost of ≈49 $ kWh −1 under an ultrahigh cathode Ni(OH) 2 loading of 280 mg cm −2 and a low anode Ru loading of ≈62.5 µg cm −2 . The advanced beyond‐industrial‐level hydrogen gas batteries provide great opportunities for practical grid‐scale energy storage applications.