TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Battery: In the redox flow battery, the half-cell electrode chamber is a cathode cell chamber and the electrode is a cathode, and the battery further comprises an anode. The half-cell electrode chamber is an anode cell chamber and the electrode is an anode, and the battery further comprises a cathode. Preferred Method: In storing, releasing, or storing and releasing electrical energy, the charge-transfer material is a polyoxometalate or derivative. The method further involves selecting the first, second, or first and second redox-active mediator from those having a structure corresponding to one of formula 1-6 below: where the aromatic or cyclic structures in each formula are optionally substituted with electron withdrawing or donating groups.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: In the redox flow battery, the additional metal is selected from metals in group 3B, 4B, 5B, or 6B.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The first, second, or first and second redox-active mediator is selected from redox-active, electrochemically reversible, cyclic or heterocyclic organic compounds. The first, second or first and second redox-active mediator has a structure corresponding to one of Formulas (1-6), where the aromatic or cyclic structures in each formula are optionally substituted with electron withdrawing or donating groups. The electron withdrawing or donating groups are present and are selected from: groups having the formula -XRn; -NO2, -CN, -CO2R, -halogens, halogenated hydrocarbons, -CF3, -COH, -SO3R, -NH3-nRn, -O2CR, amide, -OR, -NH2-mRm, and saturated or unsaturated linear, branched, cyclic or aromatic alkyl groups; and combinations.X=O, S, or N;R=a linear, branched, cyclic, aromatic alkyl group having 1-50 carbon atoms, or hydrogen, and R is optionally functionalized with a functional group including a halogen, O, S, or N;n=0 up to a valence of 3; andm=0-2.