A water electrolyzer system

A spatially decoupled redox flow water electrolyzer, comprising:

• a hydrogen-producing catholyte section comprising a catholyte tank, having a cathode, and a hydrogen generation compartment, where the catholyte tank and the hydrogen generation compartment are fluidly connected to one another by a fluid pathway, so as to facilitate the circulation of a liquid catholyte from the catholyte tank to the hydrogen generation compartment and back to the catholyte tank;
• an oxygen-producing anolyte section comprising an anolyte tank, having an anode, and an oxygen producing compartment, where the anolyte tank and the oxygen producing compartment are fluidly connected to one another by a fluid pathway, so as to facilitate the circulation of a liquid anolyte from the anolyte tank to the oxygen producing compartment and back to the anolyte tank;
• an anion-exchange membrane disposed between the catholyte and anolyte tanks that allows anions to move from the catholyte tank to the anolyte tank;
• and
• a current collector attached to the catholyte and anolyte tanks, wherein:
• the hydrogen generation compartment is configured to house a catalyst capable of catalysing hydrogen production when brought into contact with a cathodic redox mediator when the cathodic redox mediator is in a reduced state;
• and
• the oxygen generation compartment is configured to house a catalyst capable of catalysing oxygen production when brought into contact with an anodic redox mediator when the anodic redox mediator is in an oxidised state.