TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Components: The ion selective polymer electrode membrane is cation and/or proton selective. The catholyte is acidic. The ion selective polymer electrode membrane is a bi-membrane with the cation exchange membrane on the cathode side. The modified ferrocene species is present in the catholyte at a concentration of at least 0.0001M, 0.005M, or 0.001 M. The catholyte additionally comprises a catalyst redox species.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The catalyst redox species is selected from ligated transition metal complexes and/or polyoxometallate species. The transition metal(s) in the transition metal complexes are selected from manganese (II-V), iron (I-IV), copper (I-III), cobalt (I-III), nickel (I-III), chromium (II-VII), titanium (II-IV), tungsten (IV-VI), vanadium (II-V) and molybdenum (II-VI). The catalyst redox species comprises a multidentate N-donor ligand, where the N-donor ligand comprises at least one pyridine substituents. The catalyst redox species is an iron complex of N,N-bis(2-pyridylmethyl)-bis(2-pyridyl)methylamine (N4Py), pydien, trilen or its derivatives.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The spacer group in the modified ferrocene species is conjugated. The electron withdrawing substituent in the modified ferrocene species is also anionic. The modified ferrocene species is compound of formula (I) (preferably compound of formulae (II)-(VII)). The modified ferrocene species is non-ionic or anionic in its oxidized form (preferably anionic in its oxidized form).X and Y'=electron withdrawing substituent (preferably hydroxy, acyloxy, sulfate, carboxylic acid, carboxylate, sulfonate, sulfonic acid, phosphonic acid, phosphonate, phosphate, thiol, alkoxycarbonyl, alkoxy, aryloxy and from alkyl, alkenyl, aryl, cycloalkyl, alkaryl, alkenaryl, aralkyl, aralkenyl groups substituted with at least one of the above functional groups);R and R'=any spacer group (preferably alkenyl, cycloalkenyl, alkynyl, aryl, phenyl, heteroaryl, carbonyl, alpha , beta -unsaturated carbonyl, amide, imine, azo or sulfoxide, where each spacer group is further spaced from the ferrocene ring by any suitable number of spacer elements selected from alkyl, alkenyl, aryl, cycloalkyl, alkaryl, alkenaryl and acetylene);andn and m=1-10.X and Y' are both electron withdrawing and capable of providing negative charge. The R and R' either one or both are conjugated. Provided that:(1) when one ferrocene ring is mono to penta substituted by from R-X(n) substituents, then more than one R-X(n) substituent is present; or(2) when one ferrocene ring is mono to penta substituted by R'-Y'(m) substituents, then more than one R'-Y'(m) substituent is present;(3) any site on one ferrocene ring not occupied by a R-X(n) is hydrogen or is substituted with at least one functional group selected from halogen, hydroxy, amino, imino, nitro, cyano, acyl, acyloxy, sulfate, sulfonyl, sulfinyl, alkylamino, carboxy, carboxylic acid, ester, ether, amido, sulfonate, sulfonic acid, sulfonamide, phosphonic acid, phosphonate, phosphonic acid, phosphate, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, alkylsulfinyl, arylsulfinyl, alkylthio, arylthio, alkyl, alkoxy, oxyester, oxyamido, aryl, arylamino, aryloxy, heterocycloalkyl, heteroaryl, 2-5C alkenyl, 2-5C alkynyl, azido phenylsulfonyloxy or amino acid conjugates of formula -CO-W'-OH (where W' is amino acid, and from alkyl, alkenyl, aryl, cycloalkyl, alkaryl alkenaryl, aralkyl, aralkenyl groups substituted with at least one the above functional groups); or(4) any site on one ferrocene ring not occupied by a R'-Y'(m) substituent is H or is substituted with at least one functional group selected from halogen, hydroxy, amino, imino, nitro, cyano, acyl, acyloxy, sulfate, sulfonyl, sulfinyl, alkylamino, carboxy, carboxylic acid, ester, ether, amido, sulfonate, sulfonic acid, sulfonamide, phosphonic acid, phosphonate, phosphonic acid, phosphate, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, alkylsulfinyl, arylsulfinyl, alkylthio, arylthio, alkyl, alkoxy, oxyester, oxyamido, aryl, arylamino, aryloxy, heterocycloalkyl, heteroaryl, 2-5C alkenyl, 2-5C alkynyl, azido phenylsulfonyloxy or amino acid conjugates of formula -CO-W'-OH.