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.

According to one embodiment, provided is a secondary battery including a negative electrode containing a titanium-containing oxide, a positive electrode, a separator between the negative electrode and the positive electrode, a first aqueous electrolyte, a second aqueous electrolyte, and a third aqueous electrolyte. The first aqueous electrolyte is held in the negative electrode and contains 0.001% by mass to 0.5% by mass of zinc ions. The second aqueous electrolyte is held in the separator and contains 1% by mass to 5% by mass of a first compound that includes a hydrophobic portion and a hydrophilic portion. The third aqueous electrolyte is held in the positive electrode.

A system and method for optimizing electrochemical cells including electrodes employing coordination compounds by mediating water content within a desired water content profile that includes sufficient coordinated water and reduces non-coordinated water below a desired target and with electrochemical cells including a coordination compound electrochemically active in one or more electrodes, with an improvement in electrochemical cell manufacture that relaxes standards for water content of electrochemical cells having one or more electrodes including one or more such transition metal cyanide coordination compounds.

A system and method for optimizing electrochemical cells including electrodes employing coordination compounds by mediating water content within a desired water content profile that includes sufficient coordinated water and reduces non-coordinated water below a desired target and with electrochemical cells including a coordination compound electrochemically active in one or more electrodes, with an improvement in electrochemical cell manufacture that relaxes standards for water content of electrochemical cells having one or more electrodes including one or more such transition metal cyanide coordination compounds.

Aqueous anolytes for redox flow batteries are disclosed. The anolytes include a fluorenone-fluorenol derivative, an additive comprising an organic compound including one or more proton acceptor groups, an alkali metal hydroxide, and water. The additive functions as a homogeneous organocatalyst and may increase the current density of an aqueous redox flow battery including the anolyte.

Electric batteries wherein the positively charged electrode contacts an aqueous layer containing material which is reduced during electric discharge and/or metal ions are transported through special electrolyte that inhibits dendritic deposition on the negatively charged electrode. Methods described include electrolyte compositions including organoborate anions and cations with low charge density, and aqueous solutions containing bromate and/or bromide anions and high concentrations of dissolved salts.

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.

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.

This secondary battery comprises a positive electrode, a negative electrode, and an electrolyte. The electrolyte contains a solvent containing water, and a lithium salt. The negative electrode has a negative electrode active material that contains a carbon material. In the carbon material, the peak intensity ratio (D/G value) of a D band and a G band in the Raman spectrum obtained using Raman spectroscopy is 0.9 to 1.5. A coating is formed on the surface of the carbon material. In the coating, in the XPS spectrum measured using X-ray photoelectron spectroscopy, when the peak intensity of a 1s electron orbit of an F atom for which the binding energy appears near 685 eV is P1, and the peak intensity of the 1s electron orbit of an O atom for which the binding energy appears near 532 eV is P2, the ratio of the peak intensity P1 to the peak intensity P2 (P1/P2 value) is 0.6 to 3.0.

This secondary battery comprises a positive electrode, a negative electrode, and an electrolyte solution. The electrolyte solution includes a solvent containing water as a main component, and a lithium salt. The negative electrode has a negative electrode active material that includes a carbon material. The Raman spectrum of the carbon material, which is obtained by Raman spectroscopy, indicates that the peak intensity ratio between the D-band and the G-band (D/G) is 0.3 or greater. This secondary battery can suppress the reductive decomposition of the water-based electrolyte solution.