Nickel-hydrogen batteries for large-scale energy storage

Significance Rechargeable batteries offer great opportunities to target low-cost, high-capacity, and highly reliable systems for large-scale energy storage. This work introduces an aqueous nickel-hydrogen battery by using a nickel hydroxide cathode with industrial-level areal capacity of ∼35 mAh cm −2 and a low-cost, bifunctional nickel-molybdenum-cobalt electrocatalyst as hydrogen anode to effectively catalyze hydrogen evolution and oxidation reactions in alkaline electrolyte. The nickel-hydrogen battery exhibits an energy density of ∼140 Wh kg −1 in aqueous electrolyte and excellent rechargeability without capacity decay over 1,500 cycles. The estimated cost of the nickel-hydrogen battery reaches as low as ∼$83 per kilowatt-hour, demonstrating attractive potential for practical large-scale energy storage.