Ultrafast Electrical Pulse Synthesis of Highly Active Electrocatalysts for Beyond-Industrial-Level Hydrogen Gas...

The high reliability and proven ultra-longevity make aqueous hydrogen gas (H₂ ) 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 H₂ 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H₂ ) 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H₂ battery can efficiently operate under all-climate conditions (from -25 to +50 °C) with excellent durability. Notably, the NiH₂ 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.