Ultrafast Electrical Pulse Synthesis of Highly Active Electrocatalysts for Beyond-industrial-level Hydrogen Gas Batteries.

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 catalyst severely hampered its widespread applications in the 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 beyond-industrial-level nickel-hydrogen gas (Ni-H 2 ) batteries. Having a competitive low cost of about one fifth of Pt/C benchmark, this ultrafine RuNi/C catalyst displays an ultrahigh HOR mass activity of 2.34 A mg -1 at 50 mV (versus 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 (RuNi) battery can efficiently operate under all-climate conditions (from -25 to +50 °C). In addition, this battery shows an excellent durability with negligible capacity and efficiency decay over 1500 cycles at various current densities from 5 to 50 mA cm -2 . Notably, the Ni-H 2 (RuNi) battery achieves an cell-level energy density up to 183 Wh kg -1 under an ultrahigh cathode Ni(OH) 2 loading of 280 mg cm -2 (60 mAh cm -2 ) and a low anode Ru loading of ∼62.5 μg cm -2 , thereby reaching an estimated cost of the cell stack as low as ∼$49.1 kWh -1 , much superior to the state-of-the-art Ni-H 2 batteries and lithium iron phosphate batteries. The advanced beyond-industrial-level hydrogen gas batteries provide great opportunities for practical grid-scale energy storage applications. This article is protected by copyright. All rights reserved.