Redefining Decoupled Water Electrolysis as an Integrated Hydrogen‐Carrier Platform

ABSTRACT The hydrogen economy is commonly organized around four separate tasks: production, storage, transport, and release. This Perspective redefines decoupled water electrolysis (DWE) as a framework in which these functions can be integrated within a single electrochemical redox loop. By using a proton‐coupled redox mediator to decouple hydrogen and oxygen evolution in time and space, DWE stores hydrogen equivalents in a charged mediator phase and releases H 2 electrochemically or catalytically at the point of use. This architecture shifts part of hydrogen logistics from pressure‐ or temperature‐intensive processes toward ambient‐condition electrochemical operation. DWE can therefore be viewed not merely as an alternative electrolyzer architecture, but as an integrated hydrogen‐carrier platform. Within this broader framework, this Perspective focuses primarily on solution‐phase proton‐coupled mediators because their charged inventories can function as transportable liquid‐phase carriers. Although current solution‐phase DWE mediators remain disadvantaged in gravimetric capacity relative to ammonia and liquid organic hydrogen carriers (LOHCs), their system‐level value lies in ambient‐condition storage, low‐temperature on‐site H 2 release, independent scaling of power (electrolyzer stack) and energy capacity (mediator inventory), and flexible coupling to intermittent renewable electricity. We therefore propose carrier‐relevant benchmarks including full‐system capacity, storage‐and‐release efficiency, mediator retention, gas quality, delivered cost, and closed‐loop logistics.