TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Components: The redox battery comprises: two electrodes separated by an ion exchange membrane or other separator; means for supplying a first redox couple to the first electrode region of the cell; and means for supplying a second redox couple to the second electrode region of the cell, where the potential of the first redox couple is higher than that of the second redox couple, and at least the higher potential redox couple comprises polyoxometalate. In the redox battery: a large structure is a Keggin ion, and a binuclear Dawson-Wells structure; at least the polyoxometalate redox couple is provided in an aqueous solution; a current density of operation is significantly higher than the standard for a vanadium redox battery; a non stoichiometric polyoxometalate solution is used; and the polyoxometalate is present at less than 0.075 M by the concentration of the central atom.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The low potential redox couple comprises: a tungsten polyoxometalate of formula (HxW12K1O40); and vanadium(II) and vanadium(III) ions. The high potential polyoxometalate is of formula: (Xa(ZbMcOd)); (XnVyQ12-yZO40); (H3+eM1f-eVfQ12-fZO40), where the polyoxometalate is present up to 0.6 M by concentration of the central atom (Z); or (HgPhMoiVjOk), preferably hydrogen-phosphorus-molybdate-vanadium-oxide composite (H12(P3Mo18V7O85)), (H12(P2Mo12V6O82)), (H14(P2Mo10V8O62)), or (H15(P3Mo18V6O84)), where the polyoxometalate is present up to 0.6 M by concentration of phosphorus.K1 = Si, B, Co (all preferred) or P; andx = not defined;X = H, alkali metals, alkaline earth metals and/or ammonium;Z = B, P (preferred), S, As, Si, Ge, Ni, Rh, Sn, Al, Cu, I, Br, F, Fe, Co, Cr, Zn, H2, Te, Mn and/or Se;M = Mo, W, V, Nb, Ta, Mn, Fe, Co, Cr, Ni, Zn, Rh, Ru, Tl, Al, Ga, In, or other metals comprising first, second or third transition metal series and/or the lanthanide series;a = number of X necessary to charge balance the (McOd) anion;b = 0-20;c = 1-40;d = 1-180;Q = Mo or W;n = number of X necessary to charge balance the VyQ12-yZO40 anion;y = 1-6;M1 = alkali metal ions;e = 0-4;f = 1-6, preferably 3 or 4, where f is greater than or equal to e;g = number of H necessary to charge balance the PhMoiVjOk anion;h = 1-3;i = 8-20;j = 1-12; andk = 40-89.The high potential polyoxometalate is a vanadium polyoxometalate, where: the vanadium ions are added to the high potential polyoxometalate solution in the form of at east one vanadium compound comprising vanadium dioxide, vanadium(IV) oxide, vanadyl(IV) sulfate, vanadium(IV)-oxy acetylacetonate, vanadium oxy diperchlorate (VO(ClO4)2) and/or vanadium oxy di(tetrafluoroborate) (VO(BF4)2), or their hydrated versions; the vanadium compound is present at least at 0.075M, preferably at least at or equal to 1 M or 2 M; a molar ratio between the high potential polyoxometalate and the vanadium compound is at east 1:10, preferably at least 3:10; and the vanadyl(IV) sulfate is added at 0.5-2 M.