Interesting, the flow battery was invented in Australia around 1988. The solution of choice then was vanadium II and vanadium V. A Canadian company VRB-ESS used this technology as backup power and storage for some utility installations. Haven't heard much about them in the last few years. The problem with flow batteries are the cell stacks that act a lot like fuel cell stacks to convert the electrolyth into current, would break down causing cross contamination of the solution and loss of energy storage. Perhaps Redflow has found a solution to the longevity of the cell stack plates. Bring it on!