The invention relates to the use of nitrogen-containing compounds belonging to the classes of N-alkyl pyridinium halide, N-alkyl-2-alkyl pyridinium halide and 1-alkyl-3-alkyl imidazolium halide, as additives in electrolyte solutions for zinc bromine membraneless flow cells. The invention also provides electrolyte solutions comprising such additives and processes for operating said cells.

The invention relates to the use of at least one 1-alkyl-3-alkyl-pyridinium halide, in particular 1-alkyl-3-methyl-pyridinium bromide, as an additive in bromine-generating electrochemical cells, such as zinc/bromine cells. Processes for preparing 1-alkyl-3-methyl-pyridinium bromide and concentrated aqueous solutions comprising same for use as additives in the aforementioned cells, are also disclosed.

Provided is a fluoride ion secondary battery having a capacity larger than that of a conventional one. The fluoride ion secondary battery has a negative electrode including zirconium fluoride as a negative electrode active material. The zirconium fluoride may be in the form of particles with an average particle size of 100 nm or less, and the negative electrode may have a zirconium fluoride content of less than 50 % by mass. The negative electrode active material may further include metallic zirconium, which may be in the form of particles with an average particle size of 75 μm or less. The negative electrode may have a metallic zirconium content of 8% by mass or less.

Bipolar electrodes comprising a carbon felt loaded with a polymer material and a nanocarbon material are described herein. The bipolar electrodes are useful in electrochemical cells. In particular, the loaded carbon felt can be used in bipolar electrodes of zinc-halide electrolyte batteries. Processes for manufacturing the loaded carbon felt are also described, involving contacting (e.g., dipping) a carbon felt in a mixture of solvent, polymer material and nanocarbon material.

Provided are a positive electrode for a Zn—Br battery, a Zn—Br battery including the same, and a method of manufacturing the positive electrode for a Zn—Br battery. The positive electrode for a Zn—Br battery includes a carbon body doped with pyridinic nitrogen. The Zn—Br battery includes a negative electrode including a transition metal coated with zinc, the positive electrode; and an electrolyte. A pH of the electrolyte is in a range of 1.5 to 5.

A zinc bromine electrochemical cell comprises an anode-side subassembly, an insulating porous separator, and a cathode-side subassembly. The anode-side subassembly comprises an anode current collector, an anode sheet, and an anode insulating net. The cathode-side subassembly comprises a cathode insulating mesh, a cathode graphite felt, and a cathode current collector. The zinc bromine electrochemical cell is rollable, foldable, or stackable.

To improve the performance of certain multivalent metal electrodes, the electrodes can be treated prior to use in an electrochemical cell by applying a solution comprising an acid to a surface of a multivalent metal electrode, then removing excess solution comprising the acid and drying the surface of the multivalent metal electrode. The resulting electrode has an outer interphase layer comprised of a hydrated hydroxychloride comprising the multivalent metal, where the interphase layer has a thickness of less than 5 .Math.m.

The present invention provide a non-aqueous electrolyte for use in static or non-flowing rechargeable electrochemical cells or batteries, wherein the electrolyte comprises a first deep eutectic solvent comprises a zinc salt, a second deep eutectic solvent comprising one or more quaternary ammonium salts, and a hydrogen bond donor. Another aspect of the present invention also provides a non-flowing rechargeable electrochemical cell that employs the non-aqueous electrolyte of the present invention.

Provided herein are novel organic sulfonic acid or sulfonate zinc-battery electrolyte additive chemicals with surprising advantageous properties such as, but not limited to, stability and the ability to facilitate zinc plating while limiting the formation of zinc dendrites.

The present invention provide a non-aqueous electrolyte for use in static or non-flowing rechargeable electrochemical cells or batteries, wherein the electrolyte comprises a first deep eutectic solvent comprises a zinc salt, a second deep eutectic solvent comprising one or more quaternary ammonium salts, and a hydrogen bond donor. Another aspect of the present invention also provides a non-flowing rechargeable electrochemical cell that employs the non-aqueous electrolyte of the present invention.