A Low-Cost, Scalable, and Integrated Hydrogen Electrode Toward Industrial-Grade Hydrogen Batteries

Aqueous hydrogen batteries are promising candidates for large-scale energy storage because of their high reliability and long lifespan. However, their practical application remains hindered by hydrogen electrodes that suffer from insufficient catalytic activity, high cost, and limited scalability. Here, we develop an integrated hydrogen electrode (iHE) by rationally integrating a catalyst with a meter-scale, ultrathin hydrogen diffusion layer. A Ni-based catalyst is incorporated as a representative into the hydrogen diffusion layer composed of an ultrathin, porous, and hydrophobic nickel-plated membrane, yielding an electrode cost of only $3.6 m^-2, approximately 5% that of a conventional hydrogen electrode based on Pt catalyst supported on a commercial gas diffusion layer (Pt@GDL). The iHE exhibits a low polarization of 26 mV at 5 mA cm^-2 and stable operation over 1600 h. The Ni-H₂ (iHE) battery delivers a long cycle life of 3300 h with ~98% capacity retention and a negligible Coulombic efficiency decay rate of 0.033% h^-1. Furthermore, the Ni-H₂ (iHE) full cell achieves an energy cost of only one-sixth that of the Ni-H₂ (Pt@GDL) counterpart,   together with an energy density of 179.5 Wh kg^-1. These results highlight the advantages of the iHE in activity, stability, scalability, and cost, demonstrating its potential for grid-scale energy storage.