|Abstract: ||Redox flow batteries including a half-cell electrode chamber coupled to a
current collecting electrode are disclosed herein. In a general
embodiment, a separator is coupled to the half-cell electrode chamber.
The half-cell electrode chamber comprises a first redox-active mediator
and a second redox-active mediator. The first redox-active mediator and
the second redox-active mediator are circulated through the half-cell
electrode chamber into an external container. The container includes an
active charge-transfer material. The active charge-transfer material has
a redox potential between a redox potential of the first redox-active
mediator and a redox potential of the second redox-active mediator. The
active charge-transfer material is a polyoxometalate or derivative
thereof. The redox flow battery may be particularly useful in energy
storage solutions for renewable energy sources and for providing
sustained power to an electrical grid.