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.

The disclosure relates to a system comprising a holder and stored energy sources which can be placed in the holder, in particular rechargeable batteries, each having a casing which has side walls and in which are placed electrode plates oriented parallel to the side walls and nonwoven materials containing a bound electrolyte, the electrode plates being placed between adjacent nonwoven materials. The holder consists of at least two supports placed one above the other to hold stored energy sources in such a manner that the side walls of the casing which are oriented parallel to the electrode plates are oriented substantially horizontally. At least one pressure element is situated between the supports and rests on the side walls of the casing of the stored energy sources and transmits at least the weight force of the stored energy sources situated at the top of the holder to stored energy sources situated underneath the stored energy sources situated at the top.

Disclosed is an aqueous electrolyte solution having a temperature of at least 30° C. comprising a compound with at least one redox-active residue of formula (I)

(X—C.sub.5H.sub.4)Fe(Y—C.sub.5H.sub.3—Z)  (I), wherein X is a residue of formula —(C.sub.nH.sub.2n)-FG or of formula —(C.sub.nH.sub.2n)-Sp-(C.sub.nH.sub.2n)-FG or of formula —(C.sub.nH.sub.2n)-Brgp-, Y is hydrogen or a residue of formula —(C.sub.nH.sub.2n)-FG or of formula —(C.sub.nH.sub.2n)-Sp-(C.sub.nH.sub.2n)-FG, Z is hydrogen or a covalent bond, which links the residue of formula (I) with the remainder of the molecule, FG is a functional group selected from —OH, —SH, —NO.sub.3, —NO.sub.2, —CN, —OR.sub.1, —SR.sub.1, —(O—CH.sub.2—CH.sub.2).sub.o—OR.sub.2, —(O—CH.sub.2—CH.sub.2).sub.o—NR.sub.3R.sub.4R.sub.5.sup.+ (An.sup.m−).sub.1/m, —COR.sub.2, —COO.sup.− (Kat.sup.m+).sub.1/m, —COOR.sub.2, —SO.sub.3.sup.− (Kat.sup.m+).sub.1/m, —SO.sub.3R.sub.2, —SO.sub.4.sup.− (Kat.sup.m+).sub.1/m, —SO.sub.4R.sub.2, —PO.sub.4.sup.2− (Kat.sup.m+).sub.2/m, —PO.sub.4(R.sub.2).sub.2, —PO.sub.3.sup.2− (Kat.sup.m+).sub.2/m, —PO.sub.3(R.sub.2).sub.2, —NR.sub.3R.sub.4R.sub.5.sup.+ (An.sup.m−).sub.1/m —N.sup.+R.sub.3R.sub.4—C.sub.tH.sub.2t—SO.sub.3.sup.− or —NR.sub.2—SO.sub.2—R.sub.3, Brgp is a divalent bridging group which links the residue of formula (I) with the remainder of the molecule, Sp is —O—, —S—, —SO— or —SO.sub.2—, R.sub.1 is C.sub.1-C.sub.4 alkyl, R.sub.2 is hydrogen or C.sub.1-C.sub.4 alkyl, R.sub.3, R.sub.4 and R.sub.5 independently of one another represent hydrogen or alkyl, Kat is an m-valent inorganic or organic cation, An is an m-valent inorganic or organic anion, m is an integer between 1 and 4, n represents an integer between 2 and 4, t is an integer between 2 and 5, and is an integer from 1 to 50, preferably from 3 to 20.

The electrolyte may be used in redox flow batteries and is characterized by high stability of the redox active compounds at elevated temperatures.

Thermally regenerative ammonia-based battery systems and methods of their use to produce electricity are provided according to aspects described herein in which ammonia is added into an anolyte to charge the battery, producing potential between the electrodes. At the anode, metal corrosion occurs in the ammonia solution to form an ammine complex of the corresponding metal, while reduction of the same metal occurs at the cathode. After the discharge of electrical power produced, ammonia is separated from the anolyte which changes the former anolyte to catholyte, and previous anode to cathode by deposition of the metal. When ammonia is added to the former catholyte to make it as anolyte, the previous cathode becomes the anode. This alternating corrosion/deposition cycle allows the metal of the electrodes to be maintained in closed-loop cycles, and waste heat energy is converted to electricity by regeneration of ammonia, such as by distillation.

Redox flow battery systems having a supporting solution that contains Cl.sup.− ions can exhibit improved performance and characteristics. Furthermore, a supporting solution having mixed SO.sub.4.sup.2− and Cl.sup.− ions can provide increased energy density and improved stability and solubility of one or more of the ionic species in the catholyte and/or anolyte. According to one example, a vanadium-based redox flow battery system is characterized by an anolyte having V.sup.2+ and V.sup.3+ in a supporting solution and a catholyte having V.sup.4+ and V.sup.5+ in a supporting solution. The supporting solution can contain Cl.sup.− ions or a mixture of SO.sub.4.sup.2− and Cl.sup.− ions.

The present invention provides an electrolyte membrane for a redox flow battery, comprising a perfluorocarbon polymer having an ion-exchange group, wherein the perfluorocarbon polymer has equivalent weight EW of the ion-exchange group of 600 g/eq or more and 2000 g/eq or less, a craze area ratio of the electrolyte membrane is 1.5% or less, and a relative dimension of the electrolyte membrane in at least one of a X direction and a Y direction is 80% or more and less than 100% in the following relative dimension by dipping in 2 M aqueous sulfuric acid solution.

Redox flow batteries that utilize indigo carmine and derivatives thereof as electrolytes are disclosed.

The invention discloses a high voltage rechargeable Zn—MnO.sub.2 battery. The structure of the Zn—MnO.sub.2 battery includes zinc electrode/alkaline electrolyte/ion exchange membrane/acid electrolyte/MnO.sub.2 electrode. The ion exchange membrane comprises a cation exchange membrane, an anion exchange membrane or a proton exchange membrane. According to the invention, by using a composite electrolyte system (alkaline electrolyte/ion exchange membrane/acid electrolyte), a high voltage rechargeable Zn—MnO.sub.2 battery is obtained. According to the invention, an open circuit voltage of up to 2.7V is obtained, greatly improving the discharge voltage, and at the same time increasing the discharge capacity and enabling cyclic charge and discharge. The invention is of great importance in science research, beneficial to society and economics.

In some embodiments, a battery comprises an anode, a cathode, a separator disposed between the anode and the cathode, and an electrolyte in fluid communication with the anode, the cathode, and the separator. The anode can be a porous metallic zinc anode. The porous metallic zinc anode comprises pure zinc electrode, a substrate coated with zinc, a zinc substrate with a coating layer, or combinations thereof.

An electrode for an electrochemical energy storage device having interlayers of vanadium oxygen hydrate (VOH); and polyaniline (PANI) intercalated in the interlayers of VOH. A method for making the same and an electrochemical energy storage device including the aforementioned electrode are also discussed herein.