In one example, a system for a flow cell for a flow battery, comprising: a first flow field; and a polymeric frame, comprising: a top face; a bottom face, opposite the top face; a first side; a second side, opposite the first side; a first electrolyte inlet located on the top face and the first side of the polymeric frame; a first electrolyte outlet located on the top face and the second side of the polymeric frame; a first electrolyte inlet flow path located within the polymeric frame and coupled to the first electrolyte inlet; and a first electrolyte outlet flow path located within the polymeric frame and coupled to the first electrolyte outlet. In this way, shunt currents may be minimized by increasing the length and/or reducing the cross-sectional area of the electrolyte inlet and electrolyte outlet flow paths.

A nonaqueous electrolyte composition for use in a redox flow battery system, comprising: a nonaqueous supporting electrolyte; and a metal ligand complex of formula II: ##STR00001##
wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.6 are each independently H, halogen, alkyl, substituted alkyl, alkoxy, substituted alkoxy, aryloxy, substituted aryloxy, heteroaryloxy, substituted heteroaryloxy, or a polyether, ##STR00002##
wherein R.sub.5 is H, alkyl, or substituted alkyl; and M is a transition metal or zinc.

Methods and systems are provided for transporting and hydrating a redox flow battery system with a portable field hydration system. In one example, the redox flow battery system may be hydrated with the portable field hydration system in a dry state, in the absence of liquids. In this way, a redox flow battery system may be assembled and transported from a battery manufacturing facility to an end-use location off-site while the redox flow battery system is in the dry state, thereby reducing shipping costs, design complexities, as well as logistical and environmental concerns.

A system and a method for separation of ions from ions-containing medium is disclosed herein, that utilizes capacitive-faradaic fuel cells (CFFC) particles coated at least partially with catalysts capable of catalyzing redox reactions provided a reductant (fuel) and/or an oxidant, thereby polarizing the particles to more effectively absorb charged species (ions) from the water upon introducing, e.g., H.sub.2 gas or O.sub.2 gas, in the medium during the adsorption or regeneration. The same concept is utilized in a hybrid electrochemical cell for providing a system and a method for generating and converting electrochemical energy.

A system and a method for separation of ions from ions-containing medium is disclosed herein, that utilizes capacitive-faradaic fuel cells (CFFC) particles coated at least partially with catalysts capable of catalyzing redox reactions provided a reductant (fuel) and/or an oxidant, thereby polarizing the particles to more effectively absorb charged species (ions) from the water upon introducing, e.g., H.sub.2 gas or O.sub.2 gas, in the medium during the adsorption or regeneration. The same concept is utilized in a hybrid electrochemical cell for providing a system and a method for generating and converting electrochemical energy.

Self-charging electrochemical cells, including self-charging batteries that incorporate such self-charging electrochemical cells, the electrochemical cells including a cathode including a cathode active material, an electrolyte including a solvent and a salt dissolved in the solvent, the electrolyte being in contact with the cathode, where the cathode active material is transformed into a discharge product during or after a discharge of the self-charging electrochemical cell and a solubility of the cathode active material in the electrolyte is less than a solubility of the discharge product in the electrolyte.

A redox flow battery system includes an anolyte having chromium ions in solution, wherein at least a portion of the chromium ions form a chromium complex with at least one of the following: NH.sub.3, NH.sub.4.sup.+, CO(NH.sub.2).sub.2, SCN.sup.−, or CS(NH.sub.2).sub.2; a catholyte having iron ions in solution; a first half-cell including a first electrode in contact with the anolyte; a second half-cell including a second electrode in contact with the catholyte; and a first separator separating the first half-cell from the second half-cell.

The application relates to battery materials, and particularly discloses a method for preparing vanadium electrolyte for an all-vanadium redox flow battery. An example method includes: heating high-purity vanadium pentoxide, and reducing the high-purity vanadium pentoxide by using a reducing gas to obtain a low-valence vanadium oxide; mixing low-valence vanadium oxide with an activating agent, and heating and activating to obtain vanadium-containing paste electrolyte; and adding water to dissolve the vanadium-containing paste electrolyte to obtain the vanadium electrolyte with the average valence of vanadium between positive three and positive four. Compared with a finished product vanadium electrolyte, the vanadium-containing paste electrolyte is small in size, and the sulfuric acid is solidified, so that the corrosion of the sulfuric acid to a container can be reduced, the cost for transporting the vanadium-containing paste electrolyte is lower than the cost for directly transporting the vanadium electrolyte, and the vanadium electrolyte is promoted.

The application relates to battery materials, and particularly discloses a method for preparing vanadium electrolyte for an all-vanadium redox flow battery. An example method includes: heating high-purity vanadium pentoxide, and reducing the high-purity vanadium pentoxide by using a reducing gas to obtain a low-valence vanadium oxide; mixing low-valence vanadium oxide with an activating agent, and heating and activating to obtain vanadium-containing paste electrolyte; and adding water to dissolve the vanadium-containing paste electrolyte to obtain the vanadium electrolyte with the average valence of vanadium between positive three and positive four. Compared with a finished product vanadium electrolyte, the vanadium-containing paste electrolyte is small in size, and the sulfuric acid is solidified, so that the corrosion of the sulfuric acid to a container can be reduced, the cost for transporting the vanadium-containing paste electrolyte is lower than the cost for directly transporting the vanadium electrolyte, and the vanadium electrolyte is promoted.

A method for determining an average oxidation state (AOS) of a redox flow battery system includes measuring a charge capacity for a low potential charging period starting from a discharged state of the redox flow battery system to a turning point of a charge voltage; and determining the AOS using the measured charge capacity and volumes of anolyte and catholyte of the redox flow battery system. Other methods can be used to determine the AOS for a redox flow battery system or use discharge voltage instead of charging voltage.