▎ 摘　　要

Nickel-iron battery is highly desirable for energy storage systems in rural/remote areas for its safety, low cost, long cycle life. But it cannot be sealed and maintenance-free due to the hydrogen evolution reaction. Herein, we synthesized W2C nanocrystals embedded in porous graphene as catalysts for the hydrogen and oxygen recombination in the nickel-iron battery through in situ carburization of metallic W anchored on the graphene. The W2C/porous graphene nanocomposite catalyst exhibited a high performance with an average catalytic velocity of 3859 mu molh(-1)g(cat)(-1) and long catalytic life of 598,260s without decay in the catalytic performance. With the non-noble metal catalyst of W2C/porous graphene nanocomposite, a nickel-iron battery could be sealed and maintenance-free, and it also exhibited low cost; thus, the nickel-iron battery can be used for large-scale energy storage systems in rural/remote areas.