An anaerobic aluminum-water electrochemical cell is provided. The electrochemical cell includes: a plurality of electrode stacks, each electrode stack including an aluminum or aluminum alloy anode, and at least one cathode configured to be electrically coupled to the anode; one or more physical separators between each electrode stack adjacent to the cathode; a housing configured to hold the electrode stacks, an electrolyte, and the physical separators; a water injection port, in the housing, configured to introduce water into the housing, and an amount of hydroxide base sufficient to form an electrolyte having a hydroxide base concentration of at least 0.5% to at most 13% of the saturation concentration when water is introduced between the anode and the least one cathode. The aluminum or aluminum alloy of the anode is substantially free of titanium and boron.

An anaerobic aluminum-water electrochemical cell that includes: a plurality of electrode stacks, each electrode stack featuring an aluminum or aluminum alloy anode, and at least one cathode configured to be electrically coupled to the anode; one or more physical separators between each electrode stack adjacent to the cathode; a housing configured to hold the electrode stacks, an electrolyte, and the physical separators; a water injection port, in the housing, configured to introduce water into the housing. The electrochemical cell also includes an amount of hydroxide base sufficient to form an electrolyte having a hydroxide base concentration of at least 0.05 M to at most 3 M when water is introduced between the anode and at least one cathode of the electrochemical cell. The aluminum or aluminum alloy of the anode is substantially free of titanium and boron.

Systems and methods are provided for rebalancing electrolytes of a redox flow battery system. The redox flow battery system includes a positive electrolyte, a negative electrolyte, and a battery stack configured to receive the positive and negative electrolytes. Additionally, the battery stack includes an internal rebalancing reactor positioned internal to the battery stack and in fluid contact with the negative electrolyte.

The present disclosure relates to an electrochemical cell comprising a fuel electrode for oxidizing a fuel, an oxidant electrode for reducing an oxidant, and an ionically conductive medium for conducting ions between the fuel and oxidant electrodes to support electrochemical reactions at the fuel and oxidant electrodes. The ionically conductive medium comprises at least one active additive for enhancing (controlling the rate, overpotential and/or the reaction sites for) at least one electrochemical reaction within the cell. The cell further comprises an additive medium in contact with the ionically conductive medium and containing the at least one active additive capable of corroding or dissolving in the ionically conductive medium. The additive medium and/or casing is configured to release the active additive to the ionically conductive medium as a concentration of the active additive in the ionically conductive medium is depleted during operation of the cell.

Disclosed herein is a redox flow battery (RFB). The battery generally includes: a positive electrolyte that is a first metal ion, a negative electrolyte that is a second metal ion, an ion exchange membrane positioned between the positive electrolyte and the negative electrolyte. The membrane is configured to restrict and/or prevent the passage of the first metal ion and/or the second metal ion therethrough, and is configured to maintain ionic conductivity between the positive electrolyte and the negative electrolyte.

A flow battery having stable electrochemical performance is provided. The flow battery includes a separator disposed between a positive electrode and a negative electrode, a first flow plate to distribute a positive electrolyte to the positive electrode, and a second flow plate to distribute a negative electrolyte to the negative electrode. A material of at least one of the positive and negative electrodes is treated such that a surface area of the material when treated is greater than a surface area of the material when untreated. When the positive and negative electrolytes include vanadium ions, a concentration of vanadium in the positive electrolyte is different from a concentration of vanadium in the negative electrolyte to mitigate crossover-induced capacity fade.

Disclosed is a method for recovering the battery capacity of a vanadium redox flow battery, comprising: S100: determining the overall valence of vanadium ions in electrolyte reservoirs of the battery after the discharge capacity of the battery attenuates, and charging the battery; S200: adding a reducing agent to a positive electrolyte reservoir of the battery; S300: allowing self-circulation in the positive electrolyte reservoir of the battery, so as to complete a chemical reduction reaction; S400: determining the overall valence of the vanadium ions in the electrolyte reservoirs of the battery again, and determining the residue of the reducing agent; and/or S500: replenishing the reducing agent in the positive electrolyte reservoir of the battery, and repeating steps S300 to S400 until the mean value of the overall valence of the vanadium ions in the electrolyte reservoirs of the battery returns to 3.5. By means of using a liquid reducing agent, feeding is simplified, and the reaction rate of the reducing agent with a positive electrolyte having a high content of pentavalent vanadium is fast. The extent of the valence-decreasing reaction of the reducing agent and the residual amount of the reducing agent are strictly monitored, so that the risk of the performance of a stack being affected due to the residue of the reducing agent is reduced.

A method of operating an iron redox flow battery system may comprise fluidly coupling a plating electrode of an iron redox flow battery cell to a plating electrolyte; fluidly coupling a redox electrode of the iron redox flow battery cell to a redox electrolyte; fluidly coupling a ductile plating additive to one or both of the plating electrolyte and the redox electrolyte; and increasing an amount of the ductile plating additive to the plating electrolyte in response to an increase in the plating stress at the plating electrode. In this way, ductile Fe can be plated on the negative electrode, and the performance, reliability and efficiency of the iron redox flow battery can be maintained. In addition, iron can be more rapidly produced and plated at the plating electrode, thereby achieving a higher charging rate for all iron flow batteries.

A method for measuring an electrolyte balance of a redox flow battery may include: charging the redox flow battery by applying a current to a stack; measuring temperatures of an anode electrolyte solution and a cathode electrolyte solution while the redox flow battery is charged; calculating a temperature change rate of the anode electrolyte solution over time and a temperature change rate of the cathode electrolyte solution over time; deciding a first change time corresponding to an inflection point of the temperature change rate of the anode electrolyte solution over time and a second change time corresponding to an inflection point of the temperature change rate of the cathode electrolyte solution over time; and calculating an average electrolyte oxidation number of the redox flow battery, using the first change time, the second change time, an oxidation number of the anode electrolyte and an oxidation number of the cathode electrolyte.

The invention relates to an arrangement and a method for the controlled discharge of an energy store using redox shuttle additives and to the use of redox shuttle additives for the controlled discharge of an energy store. The energy store arrangement comprises a storage container with a redox shuttle additive which is dispensed into the electrolytes of the energy store upon triggering a dispensing device such that the energy store is partly or completely discharged, wherein the redox shuttle additive is oxidized on the cathode and reduced on the anode. The redox shuttle additive has a redox potential which is less than or equal to the potential of the partially or completely discharged cathode and greater than or equal to the potential of the partially or completely discharged anode.