TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Compositions: Concentration of 1st type of redox active material in 1st aqueous electrolyte is 0.5-2 M, preferably 6-10 M. Separator comprises cation exchange membrane, preferably cation conducting ceramic, cation conducting zeolite, or cation conducting glass. Preferred Parameters: The 1st aqueous electrolyte has pH of 7-10, preferably 12-14.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: Quinoxaline moiety comprises compound of formula (I) or its salt, preferably compound of formula (III-B) or its salt. Compound of formula (I) consists of compound of formula (I-a), compound of formula (I-b), or compound of formula (I-c). Cation exchange membrane is sulfonate containing fluoropolymer. The 2nd type of redox active material comprises hexacyanoiron complex, quinone, hydroquinone, or organic dye, and/or its salt, preferably ferrocyanide, ferricyanide, 1,2-dihydroxy-3,5-benzenedisulfonate (Tiron), 1,2,4-trihydroxy-3,5-benzenedisulfonate, or indigo carmine, and/or its salt.R1-R6=H, halo, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -CN, -NO2, -OR7, -N(R7)2, -C(=O)R7, -C(=O)OR7, -S(=O)2R7, or -S(=O)2OR7;R7=H, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, oxygen protecting group, or nitrogen protection group, and optionally 2 adjacent groups selected from R1-R6 are joined to form optionally substituted aryl or optionally substituted heteroaryl ring; andL2=optionally substituted alkyl chain, optionally substituted heteroalkyl chain, optionally substituted carbocyclyl ring, optionally substituted heterocyclyl ring, optionally substituted aryl ring, or optionally substituted heteroaryl ring, optionally any 2 R2 groups which are joined to form direct bond, optionally substituted alkyl chain, optionally substituted heteroalkyl chain, optionally substituted carbocyclyl ring, optionally substituted heterocyclyl ring, optionally substituted arylene ring, or optionally substituted heteroaryl ring linker. Preferred Definitions:    R1-R6=H.