In general, the present disclosure is directed to methods for synthesizing vanadium oxide nanobelts, as well as the corresponding chemical composition of the vanadium oxide nanobelts. Also described are materials which can incorporate the vanadium oxide nanobelts, such as including the vanadium oxide nanobelts as a cathode material for use in energy storage applications (e.g., batteries). The vanadium oxide nanobelts described herein display structural characteristics that may provide improved diffusion and/or charge transfer between ions. Thus, batteries incorporating implementations of the current disclosure may demonstrate improved properties such as higher capacity retention over charge discharge cycling.

The redox flow cell comprises a reaction cell having two electrode chambers for catholyte and anolyte, which are each connected to at least one store for liquid and are separated by an ion-conducting membrane, and which are equipped with electrodes, wherein the electrode chambers are each filled with electrolyte solutions comprising redox-active components dissolved or dispersed in an electrolyte solvent, as well as optionally conducting salts dissolved therein and optionally further additives. The redox flow cell is characterized by the anolyte comprising a redox-active component having one to six residues of formula I in the molecule or having one to six residues of formula II in the molecule and by the catholyte comprising a redox-active component having one to six residues of formula III in the molecule or having iron salts or by the anolyte and the catholyte having a redox-active component comprising one to six residues of formula I or of formula II in combination with one to six residues of formula III in the molecule ##STR00001##
wherein R.sub.1 is a covalent C—C-bond or a divalent bridge group, R.sub.2 and R.sub.3 independently of one another represent alkyl, alkoxy, haloalkyl, cycloalkyl, aryl, aralkyl, heterocyclyl, halogen, hydroxy, amino, nitro or cyano, X is a q-valent inorganic or organic anion, b and c independently of one another are integers from 0 to 4, q is an integer from 1 to 3, a is a number of value 2/q, and R.sub.4, R.sub.5, R.sub.6 and R.sub.7 independently of one another represent alkyl, cycloalkyl, aryl or aralkyl.

Provided is a multivalent metal-ion battery comprising an anode, a cathode, a porous separator electronically separating the anode and the cathode, and an electrolyte in ionic contact with the anode and the cathode to support reversible deposition and dissolution of a multivalent metal, selected from Ni, Zn, Be, Mg, Ca, Ba, La, Ti, Ta, Zr, Nb, Mn, V, Co, Fe, Cd, Cr, Ga, In, or a combination thereof, at the anode, wherein the anode contains the multivalent metal or its alloy as an anode active material and the cathode comprises a cathode layer of an exfoliated graphite or carbon material recompressed to form an active layer that is oriented in such a manner that the active layer has a graphite edge plane in direct contact with the electrolyte and facing or contacting the separator.

The disclosure relates to a molecular crowding type electrolyte that comprises at least one type of water-miscible/soluble polymer which acts as molecular crowding agent, a salt and a water. The disclosure also relates to a battery comprising the molecular crowding type electrolyte, and a method of using the molecular crowding electrolyte in electrochemical system such as battery that comprises an anode, a cathode and the molecular crowding type electrolyte.

A secondary battery according to the present invention comprises a positive electrode, a negative electrode and an electrolyte solution; the electrolyte solution contains a lithium salt and a solvent containing water; the negative electrode comprises a negative electrode active material that contains a carbon material; with respect to the carbon material, the peak intensity ratio (D/G value) of the D band to the G band in a Raman spectrum as obtained by Raman spectroscopy is from 0.05 to 0.7; a coating film is formed on the surface of the carbon material; and with respect to the coating film, if P1 is the peak intensity of the 1s electron orbital of an F atom at around the binding energy of 685 eV and P2 is the peak intensity of the 1s electron orbital of an O atom at around the binding energy of 532 eV in an XPS spectrum as determined by X-ray photoelectron spectroscopy, the ratio of the peak intensity P1 to the peak intensity P2, namely the value of P1/P2 is from 1.0 to 3.0.

An electrode comprises a current collector; and an active material-containing layer having active materials on the current collector. The active material-containing layer has a first surface contacting the current collector and a second surface which is opposite side of the first surface. At least one part of the second surface is covered by a compound containing Zn. When an image of the second surface is taken by Scanning Electron Microscope, the image is divided into 100 blocks, a ratio of existence of blocks having hexagonal platelet shaped compound containing Zn to the 100 blocks is calculated, and the ratio of existence of blocks is calculated with respect to 10 images, an average of the ratio of existence of blocks with respect to the 10 images is 20% or less (including 0).

Pyridinium derivatives, methods of making the pyridinium derivatives, and electrochemical cells that use the pyridinium derivatives as anolytes are provided. The pyridinium derivatives have a redox core with two or more pyridinium groups and substituents at pyridinium ring nitrogen atoms. The pyridinium derivatives can be made by reacting pyridyl reactant molecules having two or more pyridyl groups with water-soluble derivatizing reactant molecules via a hydrothermal synthesis.

A secondary battery including a positive electrode, a negative electrode, and an electrolytic solution. The negative electrode includes a carbon material electrochemically capable of absorbing and releasing lithium ions, and a solid electrolyte covering at least part of a surface of the carbon material and having lithium ion conductivity. The solid electrolyte includes a first compound represented by a general formula: Li.sub.xM1O.sub.y, where 0.5<x≤9, 1≤y<6, and the M1 includes at least one element selected from the group consisting of B, Al, Si, P, Ti, V, Zr, Nb, Ta, and La. The electrolytic solution includes a solvent and a lithium salt, and the solvent contains at least water.

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.

Electrode protection in electrochemical cells, and more specifically, electrode protection in both aqueous and non-aqueous electrochemical cells, including rechargeable lithium batteries, are presented. Advantageously, electrochemical cells described herein are not only compatible with environments that are typically unsuitable for lithium, but the cells may be also capable of displaying long cycle life, high lithium cycling efficiency, and high energy density.