Mr. Paul Blount:

It looks a lot like the lithium-ion batteries in that it is a containerised solution. Containers are filled with iron-battery cells. The electrical process of storing the energy is that during the discharge cycle the iron is allowed to rust. As this happens, the iron releases electrons, creating an electrical current. That is the discharge cycle. The rusting process can effectively be reversed by applying a current to the cell. Basically it is containers filled with these cells with iron and with an alkaline electrolyte. It works in a similar way to many other battery set-ups. The chemical mechanism consists of rusting and reversing the rusting process.