High‐Performance Flow Alkali‐Al/Acid Hybrid Fuel Cell for High‐Rate H2 Generation

Abstract Hydrogen (H 2 ) has been utilized as a versatile feedstock or promising energy carrier in a variety of fields, yet the implementation of high‐rate H 2 production presents a grand challenge for its readily accessible application. Herein, a newly alkali‐Al/acid hybrid fuel cell (3AHFC) that shows the capability of rapidly producing H 2 upon delivering a considerably high energy density is reported, which is set up by paring Al anode in alkaline anolyte with acidic catholyte and a relatively cheap nanohybrid of Ru nanoparticle decorating crumpled reduced graphene oxide (Ru/c‐rGO) as cathode catalysts. It is demonstrated that the 3AHFC can release a power density of up to 240.6 mW cm −2 with a Faradic efficiency of approaching 99% for fast H 2 generation (300 mA cm −2 ). Such hybrid electrolyte H 2 ‐generation fuel cell can also be extended for either seawater anolyte or metallic Mg anode, presenting great promise for the practice feasibility of on‐site H 2 production for applications in tough or even extreme environments.