TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Components: Electrochemical device is a lithium secondary battery, where cathode is lithium metal oxide, anode is carbon or lithium metal, and the anode and cathode are separated by a porous separator. Preferred Parameters: Redox potential of redox shuttle is 4-5 V in the electrolyte, which is a gel electrolyte.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: Alkali metal salt is lithium salt e.g. Li((C2O4)2B), Li(C2O4)BF2, LiClO4, LiBF4, LiAsF6, LiPF6, LiCF3SO3, Li(CF3SO2)2N, Li(CF3SO2)3C, LiN(SO2C2F5)2, and/or lithium alkyl fluorophosphate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: Redox shuttle contains aromatic having greater than or equal to 2 phosphinyl groups, where phosphorus atom of each phosphinyl is bonded to the aromatic ring, greater than or equal to 1 alkoxy substituent on the aromatic ring, and/or greater than or equal to 1 halogen substituent on the aromatic ring. Redox shuttle is a compound of formula I, II, or III, specifically II-1, II-2, II-3, II-4, II-5, or II-6. Formula I is of formula IA, formula II is of formula IB, IIA, or IIB and formula III is of formula IIIA. Electrolyte is of formula IIIB-1, IIIB-2, or IIIB-3. Concentration of redox shuttle is 0.0005-50 wt.%. Polar aprotic solvent is ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, dipropyl carbonate, bis(trifluoroethyl) carbonate, bis(pentafluoropropyl) carbonate, trifluoroethyl methyl carbonate, pentafluoroethyl methyl carbonate, heptafluoropropyl methyl carbonate, perfluorobutyl methyl carbonate, trifluoroethyl ethyl carbonate, pentafluoroethyl ethyl carbonate, heptafluoropropyl ethyl carbonate, perfluorobutyl ethyl carbonate, fluorinated oligomers, dimethoxyethane, triglyme, dimethylvinylene carbonate, tetraethyleneglycol, dimethyl ether, polyethylene glycol, sulfone, or gamma -butyrolactone.R1, R2, R1', R2'=H, alkyl, alkoxy, alkenyl, aryl, heteroaryl, or cycloalkyl;R3, R9=H, alkyl, alkenyl, aryl, or cycloalkyl;R4, R4'=H, halo, CN, NO2, phosphate, alkyl, alkenyl, aryl, heteroaryl, or cycloalkyl;q=1-6;t=0-2;r=6-q-t;x=1-5;y=1-2;z=0-4;R7, R8=1-10C alkyl;R10=tert. alkyl;xi=1-5;psi=1-2;zeta=1-3;R3'=H, alkyl, alkenyl, aryl, phosphate, or cycloalkyl;R5=H or OR3;R10'=H or tert. alkyl provided that greater than or equal to 1 R10' is not H;q'=0-1; andk, k', k''=0-1. Preferred Definitions:    R1, R2=alkyl, alkoxy, polyether, or aryl, and Me, Et, n-propyl, isopropyl, n-butyl, iso-butyl, tert. butyl, or Ph in IIB;    R1', R2'=isopropyl or Ph;    R3=alkyl, haloalkyl, phosphate, or polyether, and H, Me, Et, n-propyl, isopropyl, n-butyl, iso-butyl, or tert. butyl in IIB;    R3'=Me or Et;    R4=H, halo, alkyl, haloalkyl, or polyether;    R4'=H, F, Cl, Br, or I; and    x, y, z, q, t, r=2.