A zinc based rechargeable redox static energy storage device includes a cathode including a carbon material—binder composition and an anode including carbon material—Zinc material—binder composition both infused with an eutectic electrolyte comprising one or more inorganic transition metal salt(s) of zinc, one or more Metal hydroxide(s) and eutectic solvent comprising derivative(s) of methanesulfonic acid, ammonium salt(s) and hydrogen bond donor(s); a separator separating the cathode and anode so that the ion exchange carries in between the cathode and anode through ionic permeability; and current collector connected with the cathode and anode respectively.

A redox flow battery system includes at least two battery modules, a bidirectional converter, and a controller. The battery modules are connected in series and are connected to the converter. Each battery module has a cell array with a plurality of redox flow cells and a tank device for storing electrolyte and supplying electrolyte to the cell array. The battery system further includes a DC-to-DC converter for each battery module, one terminal of each DC-to-DC converter being connected to one battery module, and a second terminal of each DC-to-DC converter being connected to a common DC bus. An additional converter is connected to the DC bus. The controller is connected to the additional converter and to the DC-to-DC converters in such a way that the controller can control the additional converter and the DC-to-DC converters.

Systems and methods are provided for mechanical pretreatment of bipolar plates, for example, for plating electrodes in redox flow batteries. In one example, a method for disrupting surfaces of a bipolar plate may include pressing the bipolar plate between imprint plates, and removing the pressed bipolar plate from the imprint plates prior to use in a redox flow battery. In some examples, the pressed bipolar plate may include negative indentations from at least one of the imprint plates. In some examples, the imprint plates may be patterned meshes, such that the negative indentations may include patterns of asymmetric protrusions. In this way, the bipolar plate may be pretreated via pressing so as to reduce wear to manufacturing equipment (relative to other mechanical pretreatment processes, for example) while maintaining electrochemical performance of the redox flow battery.

A method is provided to optimize the surface of a carbon electrode for flow battery. A reaction solution is prepared as containing a requested ratio of functional group. After spraying the reaction solution on the carbon electrode, a number of related parameters of an atmospheric plasma are set for activation the carbon electrode. Thus, the functional group is covalently bonded on the surface of the carbon electrode according to requirement. Thereby, an accurate control of the type and number of the functional group bonded on the surface of the carbon electrode is achieved with the stability and performance of flow battery further enhanced.

A modular flow battery includes a battery stack container housing a plurality of redox flow battery stacks in fluid communication with at least one pair of electrolyte containers including an anolyte container for holding an anolyte and a catholyte container for holding a catholyte. Additional pairs of electrolyte containers can be connected to the battery stack container to increase an amount of energy that can be stored by the modular flow battery system. Respective housings enclosing each of the battery stack container and the electrolyte containers are configured for operation in a stacked configuration. In this manner, the energy storage capacity of the modular flow battery system can be further increased with substantially no increase in a lateral area occupied by the system.

A redox flow battery includes first and second cells. Each cell has electrodes and a separator layer arranged between the electrodes. A first circulation loop is fluidly connected with the first electrode of the first cell. A polysulfide electrolyte solution has a pH 11.5 or greater and is contained in the first recirculation loop. A second circulation loop is fluidly connected with the second electrode of the second cell. An iron electrolyte solution has a pH 3 or less and is contained in the second circulation loop. A third circulation loop is fluidly connected with the second electrode of the first cell and the first electrode of the second cell. An intermediator electrolyte solution is contained in the third circulation loop. The cells are operable to undergo reversible reactions to store input electrical energy upon charging and discharge the stored electrical energy upon discharging.

A flow battery system can include at least one pair of electrolyte storage, a first battery stack, and a second battery stack. The electrolyte storage pair can include an anolyte storage configured to contain an anolyte solution, and a catholyte storage configured to contain a catholyte solution. The first battery stack can be fluid communication with the electrolyte storage pair. The first battery stack can also be configured to receive electrical energy from a power source and to facilitate redox reactions storing the received electrical power as chemical energy by the anolyte and catholyte solutions. The second battery stack can be in fluid communication with the at least one pair of electrolyte storage. The second battery stack can also be configured to supply electrical energy to an electrical load, and to facilitate redox reactions releasing chemical energy stored by the anolyte and catholyte solutions as electrical energy to the load.

A fluoro sulfonated poly(phenylene) was rationally designed with an external hydrophobic shell and internal hydrophilic core in order to improve the durability and ion selectivity of a hydrocarbon membrane for vanadium redox flow batteries (VRFBs). The polymer was designed to prevent hydrophilic polymer chain aggregation by attaching acid moieties onto the polymer backbone, while functionalizing the external polymer shell with hydrophobic side chains to prevent excessive vanadium crossover associated with cation exchange membranes. As an example, the hydrophobic shell can be provided by pentafluorobenzoyl group functionalization of the pendent aryl groups on a Diels Alder poly(phenylene) backbone, while the internal polymer chain can contain sulfonic acid moieties to impart hydrophilic character.

An electrode assembly for a flow battery is disclosed comprising a porous electrode material, a frame surrounding the porous electrode material, at least a distributor tube embedded in the porous electrode material having an inlet for supplying electrolyte to the porous electrode material and at least another distributor tube embedded in the porous electrode material having an outlet for discharging electrolyte out of the porous material. The walls of the distributor tubes are preferably provided with holes or pores for allowing a uniform distribution of the electrolyte within the electrode material. The distributor tubes provide the required electrolyte flow path length within the electrode material to minimize shunt current flowing between the flow cells in the battery stack.

A method of cleansing a redox flow battery system may include operating the redox flow battery system in a charge, discharge, or idle mode, and responsive to a redox flow battery capacity being less than a threshold battery capacity, mixing the positive electrolyte with the negative electrolyte. In this way, battery capacity degradation following cyclic charging and discharging of the redox flow battery system can be substantially reduced.