Systems and methods drawn to an electrochemical cell comprising a low temperature ionic liquid comprising positive ions and negative ions and a performance enhancing additive added to the low temperature ionic liquid. The additive dissolves in the ionic liquid to form cations, which are coordinated with one or more negative ions forming ion complexes. The electrochemical cell also includes an air electrode configured to absorb and reduce oxygen. The ion complexes improve oxygen reduction thermodynamics and/or kinetics relative to the ionic liquid without the additive.

Provided is an energy harvesting device for producing electric power by conduction of alkali ions, including a laminated film in which two-dimensional (2D) materials are laminated and assembled, wherein the laminated film includes a first region into which alkali ions are introduced, a second region into which alkali ions are introduced at a concentration lower than that of the first region or into which alkali ions are not introduced, and a third region located between the first region and the second region to divide the first region and the second region, and in which an interlayer distance between the 2D materials is fixed by physical constraints.

Stable and high performance positive and negative electrolytes compositions to be used in redox flow battery systems are described. The redox flow battery system, comprises: at least one rechargeable cell comprising a positive electrolyte, a negative electrolyte, and an ionically conductive membrane positioned between the positive electrolyte and the negative electrolyte, the positive electrolyte in contact with a positive electrode, and the negative electrolyte in contact with a negative electrode. The positive electrolyte consists essentially of water, a first amino acid, an inorganic acid, an iron precursor, a supporting electrolyte, and optionally a boric acid. The negative electrolyte consists essentially of water, the iron precursor, the supporting electrolyte, and a negative electrolyte additive. The iron precursor is FeCl.sub.2, FeCl.sub.3, FeSO.sub.4, Fe.sub.2(SO.sub.4).sub.3, FeO, Fe, Fe.sub.2O.sub.3, or combinations thereof. The supporting electrolyte is LiCl, NaCl, Na.sub.2SO.sub.4, KCl, NH.sub.4Cl, or combinations thereof. The negative electrolyte additive is boric acid or a combination of the boric acid and a second amino acid.

Stable and high performance positive and negative electrolytes compositions to be used in redox flow battery systems are described. The redox flow battery system, comprises: at least one rechargeable cell comprising a positive electrolyte, a negative electrolyte, and an ionically conductive membrane positioned between the positive electrolyte and the negative electrolyte, the positive electrolyte in contact with a positive electrode, and the negative electrolyte in contact with a negative electrode. The positive electrolyte consists essentially of water, a first amino acid, an inorganic acid, an iron precursor, a supporting electrolyte, and optionally a boric acid. The negative electrolyte consists essentially of water, the iron precursor, the supporting electrolyte, and a negative electrolyte additive. The iron precursor is FeCl.sub.2, FeCl.sub.3, FeSO.sub.4, Fe.sub.2(SO.sub.4).sub.3, FeO, Fe, Fe.sub.2O.sub.3, or combinations thereof. The supporting electrolyte is LiCl, NaCl, Na.sub.2SO.sub.4, KCl, NH.sub.4Cl, or combinations thereof. The negative electrolyte additive is boric acid or a combination of the boric acid and a second amino acid.

A fuel cell system includes a fuel exhaust gas inlet channel for guiding a fuel exhaust gas containing liquid water discharged from a fuel cell stack to a gas liquid separator provided downstream of a humidifier in an oxygen-containing gas inlet channel. The specific gravity of the fuel exhaust gas is lighter than the specific gravity of the oxygen-containing exhaust gas. An outlet channel of the gas liquid separator includes a stirring booster having a first point and a second point positioned downstream of the first point. The second point is positioned ahead of the first point in the gravity direction.

A fuel cell system includes a fuel exhaust gas inlet channel for guiding a fuel exhaust gas containing liquid water discharged from a fuel cell stack to a gas liquid separator provided downstream of a humidifier in an oxygen-containing gas inlet channel. The specific gravity of the fuel exhaust gas is lighter than the specific gravity of the oxygen-containing exhaust gas. An outlet channel of the gas liquid separator includes a stirring booster having a first point and a second point positioned downstream of the first point. The second point is positioned ahead of the first point in the gravity direction.

Stable solutions comprising high concentrations of charged coordination complexes, including iron hexacyanides are described, as are methods of preparing and using same in chemical energy storage systems, including flow battery systems. The use of these compositions allows energy storage densities at levels unavailable by other iron hexacyanide systems.

Stable solutions comprising high concentrations of charged coordination complexes, including iron hexacyanides are described, as are methods of preparing and using same in chemical energy storage systems, including flow battery systems. The use of these compositions allows energy storage densities at levels unavailable by other iron hexacyanide systems.

A negative electrode electrolyte solution for a redox flow battery includes a negative electrode active material, a negative electrode supporting salt, and a negative electrode solvent, in which the negative electrode solvent is a solvent having an octanol-water partition coefficient Log P.sub.OW expressed by Log P of 1.5 or more.

A negative electrode electrolyte solution for a redox flow battery includes a negative electrode active material, a negative electrode supporting salt, and a negative electrode solvent, in which the negative electrode solvent is a solvent having an octanol-water partition coefficient Log P.sub.OW expressed by Log P of 1.5 or more.