Provided is an electrolyte membrane including at least the following: an A-layer composed of an ion-conducting fluorinated polymer and a non-ion-conducting fluorinated polymer; and a B-layer composed of an ion-conducting hydrocarbon polymer, wherein the ion-conducting hydrocarbon polymer is dispersed in the A-layer. Provided is an electrolyte membrane having excellent oxidation resistance. In addition, provided is an electrolyte membrane for a redox-flow battery, in which the electrolyte membrane used as a barrier membrane for a redox-flow battery makes it possible to achieve high power efficiency and stable charge and discharge even in long-term use.

A redox matched flow battery utilizes insoluble functionalized catholyte and anolyte beads to store charge on redox-active moieties tethered to the beads, with charge being transferred between the electrodes and the bead using a soluble, redox-matched mediator.

A redox flow battery and battery system are provided. In one example, the redox flow battery includes a set of pressure plates having a first pressure plate at a first terminal end and a second pressure plate at a second terminal end, the second terminal end and the first terminal end positioned on opposing longitudinal sides of the redox flow battery. The redox flow battery further includes a first cell stack positioned longitudinally between the first pressure plate and the second pressure plate, each of the first and second pressure plates includes a plurality stacking detents on a first flange and a plurality of stacking protrusions on a second flange, and the first flange and the second flange arranged on opposing vertical sides of the redox flow battery.

A redox flow battery includes: a negative electrode; a positive electrode; a first liquid which is in contact with the negative electrode, and which contains a first nonaqueous solvent, a first redox species, and metal ions; a second liquid which is in contact with the positive electrode, and which contains a second nonaqueous solvent, a second redox species, and metal ions; and a metal ion-conducting membrane disposed between the first liquid and the second liquid. The metal ion-conducting membrane contains an organic polymer containing a plurality of hydroxy groups. The organic polymer contains a group formed by substituting at least a portion of the hydroxy groups with a metal sulfonate.

A polyelectrolyte multilayer membrane has been developed for redox flow batteries and other electrochemical reaction applications. The polyelectrolyte multilayer membrane comprises an ionically conductive thin film composite membrane comprising a microporous support membrane, a hydrophilic ionomeric polymer coating layer on the surface of the microporous support membrane, and a polyelectrolyte multilayer coating on the second surface of the hydrophilic ionomeric polymer coating layer (the side opposite the support membrane). The polyelectrolyte multilayer coating comprises alternating layers of a polycation polymer and a polyanion polymer. Methods of making the polyelectrolyte multilayer membrane and redox flow battery system including the polyelectrolyte multilayer membrane are also described.

A system and method for a flowing electrolyte battery enables compression plates to be produced from a uni-directional glass fibre reinforced thermoplastic composite. The system includes: a cell stack of electrodes and separators, with a compression plate consisting of thermoplastic composite with uni-directional glass fibre reinforcement layers, with at least one layer of the uni-directional glass fibre configured in a direction perpendicular to a direction of another layer of uni-directional glass fibre; at least one integral manifold adjacent to the cell stack configured to seal the cell stack; and side plates consisting of thermoplastic composite with a plurality of uni-directional glass fibre layers configured in a direction perpendicular to the compression plates, the side plates consisting of at least one surface layer of a first end layer or a second end layer of thermoplastic composite having less uni-directional glass fibre content than another layer.

Low cost membrane electrode assemblies (MEA) with improved coulombic efficiency (CE), reduced maintenance cost, and improved deliverable capacity have been developed for redox flow batteries and other electrochemical reaction applications. The MEA comprises: a microporous substrate membrane, first and second hydrophilic ionomeric polymer coating layers on surfaces of the microporous substrate membrane, and an electrode adhered to a second surface of the second hydrophilic ionomeric polymer coating layer. Methods of preparing the MEA and a redox flow battery system incorporating the MEA are also described.

A bipolar plate is disposed between a positive electrode and a negative electrode of a redox flow battery. The bipolar plate has, in a surface of the bipolar plate facing at least one of the positive electrode and the negative electrode, a plurality of grooves through which an electrolyte flows and a ridge positioned between the adjacent grooves. The bipolar plate includes rough surfaces which are disposed in at least parts of groove inner surfaces defining the respective grooves and surface roughness of which represented by arithmetic mean roughness Ra is 0.1 μm or larger.

Systems and methods for operating an electric energy storage device are described. The systems and methods may generate a state of charge estimate that is based on negative electrode plating. An overall state of charge may be determined from the state of charge estimate that is based on negative electrode plating and a state of charge estimate that is not based on negative electrode plating.

Methods and systems are provided for a redox flow battery system. In one example, a method of operating a redox flow battery system includes switching the redox flow battery system to an idle mode and completely draining electrolytes from one or more electrode compartments of the redox flow battery system. The one or more electrode compartments may be purged with a gas and refilled with fresh electrolytes.