A system includes a flow battery and a temperature control system. The flow battery is configured to thermally manage a thermal load. In some embodiments, the flow battery is also configured to electrically power the thermal load. The temperature control system is configured to cool electrolyte in the flow battery in response to the thermal load being inactive.

A polymer electrolyte membrane according to the present invention has a cluster diameter of 2.96 to 4.00 nm and a converted puncture strength of 300 gf/50 μm or more. The polymer electrolyte membrane according to the present invention has a low electric resistance and an excellent mechanical strength.

A redox flow battery system includes a redox flow battery that has a redox flow cell and a supply/storage system. The supply/storage system has first and second electrolytes for circulation through the redox flow cell. At least the first electrolyte is a liquid electrolyte that has electrochemically active species with multiple, reversible oxidation states. A secondary cell is operable to monitor concentration of one or more of the electrochemically active species. The secondary cell has a counter electrode, a flow passage that connects the counter electrode with the redox flow battery to receive the first or second electrolyte, a working electrode, and a separator. The working electrode is isolated from receiving the electrochemically active species of the first and second electrolytes except for a transport passage connecting the flow passage and the working electrode. The transport passage limits movement of the electrochemically active species to the working electrode.

A zinc-bromine flow battery is proposed. The battery may include a conductive interlayer that can reduce the amount of inactive zinc in the form of dendrites on a negative electrode, thereby improving the zinc desorption process and improving the capacity and lifespan characteristics of the battery. The battery may include a membrane, a first electrode stacked on one side of the membrane, and a second electrode stacked on other side of the membrane. The battery may also include a conductive interlayer interposed between a negative electrode from among the first and second electrodes and the membrane and having a log value of hydrogen generation exchange current density of −4 or less in an acid-based electrolyte.

A flow battery includes a positive electrode, a positive electrode electrolyte, a negative electrode, a negative electrode electrolyte, and a polymer electrolyte membrane interposed between the positive electrode and the negative electrode. The positive electrode electrolyte includes water and a first redox couple. The first redox couple includes a first organic compound which includes a first moiety in conjugation with a second moiety. The first organic compound is reduced during discharge while during charging the reduction product of the first organic compound is oxidized to the first organic compound. The negative electrode electrolyte includes water and a second redox couple. The second couple includes a second organic compound including a first moiety in conjugation with a second moiety. The reduction product of the second organic compound is oxidized to the second organic compound during discharge.

All-vanadium sulfate redox flow battery systems have a catholyte and an anolyte comprising an aqueous supporting solution including chloride ions and phosphate ions. The aqueous supporting solution stabilizes and increases the solubility of vanadium species in the electrolyte, allowing an increased vanadium concentration over a desired operating temperature range. According to one example, the chloride ions are provided by MgCl.sub.2, and the phosphate ions are provided by (NH.sub.4).sub.2HPO.sub.4.

Ferrocene based redox-active compounds have a total number of cyclopentadienyl substituents that is three or greater per ferrocene core. The cyclopentadienyl substituents generally have a linker and a solubilizing group. An aqueous solution of the redox-active compound and a salt may be used as an electrolyte. Aqueous compositions including the redox-active compounds may be used in electrodialysis systems.

A redox flow battery includes positive and negative electrodes respectfully located in half-cells separated by a porous silicon wafer separator formed by MEMS Technology. The first half cell and the second half cell each preferably include a plurality of dividers or barriers configured to create flow channels which introduce turbulence insuring the electrolytes are changing or mixing at surfaces of the electrodes and the membrane. Also disclosed is a solar energy generation and storage system which includes a photovoltaic cell and an electrochemical energy storage battery which share a common electrode. Also disclosed is a membrane-less redox flow electrical energy storage battery, having a cathode electrode; an anode electrode formed of a porous silicon substrate in which surfaces of the pores of the porous silicon substrate are coated at least in part with a metal silicide; and, an electrolyte.

A method of rebalancing electrolytes in a redox flow battery system comprises directing hydrogen gas generated on the negative side of the redox flow battery system to a catalyst surface, and fluidly contacting the hydrogen gas with an electrolyte comprising a metal ion at the catalyst surface, wherein the metal ion is chemically reduced by the hydrogen gas at the catalyst surface, and a state of charge of the electrolyte and pH of the electrolyte remain substantially balanced.

A membrane with high ion selectivity, balancing influence on vanadium transport in all-vanadium redox-flow environment, high physicochemical stability and potentially low cost is an amphoteric ion exchange membrane with defined ratio of anion and cation exchange capacity, in particular for redox flow batteries. The membrane includes a mechanically robust and chemically resistant base polymer film (matrix), ion exchange groups covalently bound to the polymer matrix, being a mixture of anion and cation exchange groups, a comonomer including two anion exchange groups per molecule to yield a ratio of anion exchange groups to cation exchange groups of 1.5-4 (50-300% excess of anion exchange groups over cation exchange groups) to balance transport of positively charged redox-active ions, a quaternary bonded alpha-C atom in comonomers to protect the resulting polymer sterically against chemical degradation. Optionally, additional functional constituents, such as crosslinkers and/or antioxidants are provided.