WO2018111636A1

WO2018111636A1 - Monopolar plate-electrode assemblies and electrochemical cells and liquid flow batteries therefrom

Info

Publication number: WO2018111636A1
Application number: PCT/US2017/064820
Authority: WO
Inventors: Raymond P. Johnston; Gregory M. Haugen; Brian T. Weber; Onur S. Yordem; Bharat R. Acharya
Original assignee: 3M Innovative Properties Company
Priority date: 2016-12-13
Filing date: 2017-12-06
Publication date: 2018-06-21

Abstract

The present disclosure relates to monopolar plate-electrode assemblies and electrochemical cells and liquid flow batteries produced therefrom. A monopolar plate-electrode assembly including (i) a flow plate substrate having a first major surface and an opposed second major surface wherein the first major surface includes at least one flow channel and wherein the flow plate substrate includes at least one via intersecting the channel bottom of the at least one flow channel and the second major surface of the flow plate substrate; (ii) a porous electrode material contained in at least a portion of the at least one flow channel; and (iii) an electrically conductive material contained in at least a portion of the at least one via, wherein the electrically conductive material is in electrical communication with the porous electrode material. The disclosure further provides methods of making the monopolar plate-electrode assemblies.

Description

Monopolar Plate-Electrode Assemblies and Electrochemical Cells and Liquid Flow

Batteries Therefrom

FIELD

The present invention generally relates to assemblies useful in the fabrication of electrochemical cells and batteries. In particular, the present invention relates to monopolar plate-electrode assemblies (MPPEAs) and electrochemical cells and liquid flow batteries produced therefrom. The disclosure further provides methods of making the monopolar plate-electrode assemblies.

BACKGROUND

Various components useful in the formation of electrochemical cells and redox flow batteries have been disclosed in the art. Such components are described in, for example, U.S. Pat. Nos. 5,648,184, 8,518,572 and 8,882,057.

SUMMARY

In one embodiment, the present disclosure provides a monopolar plate-electrode assembly comprising:

a flow plate substrate having a first major surface and an opposed second major surface in the x-y plane of the monopolar plate-electrode assembly, wherein the first major surface includes at least one flow channel, allowing fluid flow in the x-y plane of the monopolar plate-electrode assembly, the at least one flow channel is in fluid communication with a fluid inlet port and a fluid outlet port of the flow plate substrate, and wherein the flow plate substrate includes at least one via intersecting the channel bottom of the at least one flow channel and the second major surface of the flow plate substrate;

a porous electrode material contained in at least a portion of the at least one flow channel; and

an electrically conductive material contained in at least a portion of the at least one via, wherein the electrically conductive material is in electrical communication with the porous electrode material; and wherein the monopolar plate-electrode assembly exhibits electrical communication through the thickness of the flow plate substrate and does not exhibit fluid communication through the thickness of the flow plate substrate. In another embodiment, the present disclosure provides a method of forming a monopolar plate-electrode assembly comprising:

providing a flow plate substrate having a first major surface and an opposed second major surface in the x-y plane of the monopolar plate-electrode assembly, wherein the first major surface includes at least one flow channel, allowing fluid flow in the x-y plane of the monopolar plate-electrode assembly, the at least one flow channel is in fluid communication with a fluid inlet port and a fluid outlet port of the flow plate substrate, and wherein the flow plate substrate includes at least one via intersecting the channel bottom of the at least one flow channel and the second major surface of the flow plate substrate;

disposing a porous electrode material in at least a portion of the at least one flow channel; and

disposing an electrically conductive material in at least a portion of the at least one via, wherein the electrically conductive material is in electrical communication with the porous electrode material, thereby forming a monopolar plate-electrode assembly, wherein the monopolar plate-electrode assembly exhibits electrical communication through the thickness of the flow plate substrate and does not exhibit fluid communication through the thickness of the flow plate substrate.

In another embodiment, the present disclosure provides an electrochemical cell for a liquid flow battery including at least one monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the present disclosure. In yet another embodiment, the present disclosure provides an electrochemical cell for a liquid flow battery including two half cells, each half cell including an electrode, wherein at least one of the half cells includes a monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the present disclosure.

In another embodiment, the present disclosure provides liquid flow battery including at least one monopolar plate-electrode assembly according to any one of the monopolar plate- electrode assemblies of the present disclosure. In yet another embodiment, the present disclosure provides a liquid flow battery comprising at least one electrochemical cell, the electrochemical cell including two half cells, each half cell including an electrode, wherein at least one of the half cells includes a monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A is a schematic top view of an exemplary flow plate substrate according to one exemplary embodiment of the present disclosure.

FIG. IB is a schematic bottom view of the exemplary flow plate substrate of FIG. 1 A according to one exemplary embodiment of the present disclosure.

FIG. 1C is a schematic cross-sectional side view of the exemplary flow plate substrate of FIG. 1 A according to one exemplary embodiment of the present disclosure.

FIG. ID is a schematic side view of the front face or back face of the exemplary flow plate substrate of FIG. 1 A according to one exemplary embodiment of the present disclosure.

FIG. 2A is a schematic top view of an exemplary monopolar plate-electrode assembly according to one exemplary embodiment of the present disclosure.

FIG. 2B is a schematic bottom view of the exemplary monopolar plate-electrode assembly of FIG. 2A according to one exemplary embodiment of the present disclosure.

FIG. 2C is a schematic cross-sectional side view of the exemplary monopolar plate- electrode assembly of FIG. 2 A according to one exemplary embodiment of the present disclosure.

FIG. 2D is a schematic side view of the front face or back face of the exemplary monopolar plate-electrode assembly of FIG. 2 A according to one exemplary embodiment of the present disclosure.

FIG. 3 A is a schematic top view of an exemplary flow plate substrate according to one exemplary embodiment of the present disclosure.

FIG. 3B is a schematic bottom view of the exemplary flow plate substrate of FIG. 3 A according to one exemplary embodiment of the present disclosure.

FIG. 3C is a schematic cross-sectional side view of the exemplary flow plate substrate of FIG. 3 A according to one exemplary embodiment of the present disclosure.

FIG. 3D is a schematic side view of the front face or back face of the exemplary flow plate substrate of FIG. 3 A according to one exemplary embodiment of the present disclosure.

FIG. 4A is a schematic top view of an exemplary monopolar plate-electrode assembly according to one exemplary embodiment of the present disclosure.

FIG. 4B is a schematic bottom view of the exemplary monopolar plate-electrode assembly of FIG. 4A according to one exemplary embodiment of the present disclosure.

FIG. 4C is a schematic cross-sectional side view of the exemplary monopolar plate- electrode assembly of FIG. 4 A according to one exemplary embodiment of the present disclosure. FIG. 4D is a schematic side view of the front face or back face of the exemplary monopolar plate-electrode assembly of FIG. 4 A according to one exemplary embodiment of the present disclosure.

FIG. 4C-1 is a schematic cross-sectional side view of an exemplary monopolar plate- electrode assembly according to one exemplary embodiment of the present disclosure.

FIG. 4C-2 is a schematic cross-sectional side view of an exemplary monopolar plate- electrode assembly according to one exemplary embodiment of the present disclosure.

FIG. 4C-3 is a schematic cross-sectional side view of an exemplary monopolar plate- electrode assembly according to one exemplary embodiment of the present disclosure.

FIG. 5 A is a schematic cross-sectional side view of an exemplary electrochemical cell according to one exemplary embodiment of the present disclosure.

FIG. 5B is a schematic cross-sectional side view of an exemplary electrochemical cell according to one exemplary embodiment of the present disclosure.

FIG. 6 is a schematic cross-sectional side view of an exemplary electrochemical cell stack according to one exemplary embodiment of the present disclosure.

FIG. 7 is a schematic cross-sectional side view of an exemplary single cell, liquid flow battery according to one exemplary embodiment of the present disclosure.

Repeated use of reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the disclosure. The drawings may not be drawn to scale. As used herein, the word "between", as applied to numerical ranges, includes the endpoints of the ranges, unless otherwise specified. The recitation of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure. As used in this specification and the appended claims, the singular forms "a", "an", and "the" encompass embodiments having plural referents, unless the context clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the context clearly dictates otherwise.

Throughout this disclosure, when a surface of one substrate is in "contact" with the surface of another substrate, there are no intervening layer(s) between the two substrates and at least a portion of the surfaces of the two substrates are in physical contact.

Throughout this disclosure, if a substrate or a surface of a substrate is "adjacent" to a second substrate or a surface of a second substrate, the two nearest surfaces of the two substrates are considered to be facing one another. They may be in contact with one another or they may not be in contact with one another, an intervening third layer(s) or substrate(s) being disposed between them.

Throughout this disclosure the phrase "non-conductive" refers to a material or substrate that is non-electrically conductive, unless otherwise stated. In some embodiments, a material or substrate is non-electrically conductive if it has an electrical resistivity of greater than 1000 ohm-m. In some embodiments, a material or substrate is electrically conductive if it has an electrical resistivity of less than 1000 ohm-m, less than 1 ohm-m, less than 0.001 ohm-m, less than 0.0001 ohm-m or even less than 0.00001 ohm-m.

Throughout this disclosure, an aqueous based solution is defined as a solution wherein the solvent includes at least 50% water by weight. A non-aqueous based solution is defined as a solution wherein the solvent contains less than 50% water by weight.

Throughout this disclosure, unless indicated otherwise, the word "fiber" is meant to include both the singular and plural forms.

Throughout this disclosure fluid communication between a first surface and a second surface of a substrate means that a fluid, e.g. gas and/or liquid, is capable of flowing continuously from a first surface of the substrate, through the thickness of a substrate, to a second surface of the substrate. This inherently implies that there is a continuous fluid pathway extending from the first surface of the substrate, through the thickness of the substrate, to a second surface of the substrate. Diffusion of molecules through a solid substrate is not considered to be "fluid communication".

Throughout this disclosure, the phrase "impervious to fluid" means fluid cannot pass through a substrate via fluid flow caused by an external force, e.g. gravity or an applied load. A substrate that allows diffusive mass transport but not fluid flow caused by an external force may be considered to be impervious to fluid. Softening Temperature is the glass transition temperature and/or the melting temperature of a polymer.

In some embodiments, an integral structure includes a structure that can be held in any orientation in space and does not separate into at least two components, due to the force of gravity.

DETAILED DESCRIPTION

A single electrochemical cell, which may be used in the fabrication of a liquid flow battery (e.g. a redox flow battery), generally, includes two porous electrodes, an anode and a cathode; an ion permeable membrane disposed between the two electrodes, providing electrical insulation between the electrodes and providing a path for one or more select ionic species to pass between the anode and cathode half-cells; anode and cathode flow plates, the former positioned adjacent the anode and the later positioned adjacent the cathode, each containing one or more channels which allow the anolyte and catholyte electrolytic solutions to contact and penetrate into the anode and cathode, respectively. When the anode and cathode flow plates each include one or more channels on only one of their associated major surfaces and subsequently include either anolyte or catholyte, respectively, the flow plates are considered to be monopolar flow plates. In a redox flow battery containing a single electrochemical cell, for example, the cell would also include two current collectors, one adjacent to and in contact with the exterior surface of the anode flow plate and one adjacent to and in contact with the exterior surface of the cathode flow plate. The current collectors allow electrons generated during cell discharge to connect to an external circuit and do useful work. A functioning redox flow battery or electrochemical cell also includes an anolyte, anolyte reservoir and corresponding fluid distribution system (piping and at least one or more pumps) to facilitate flow of anolyte into the anode half-cell, and a catholyte, catholyte reservoir and corresponding fluid distribution system to facilitate flow of catholyte into the cathode half-cell. Although pumps are typically employed, gravity feed systems may also be used. During discharge, active species, e.g. cations, in the anolyte are oxidized and the corresponding electrons flow through the exterior circuit and load to the cathode where they reduce active species in the catholyte. As the active species for electrochemical oxidation and reduction are contained in the anolyte and catholyte, redox flow cells and batteries have the unique feature of being able to store their energy outside the main body of the

electrochemical cell, i.e. in the anolyte. The amount of storage capacity is mainly limited by the amount of anolyte and catholyte, the concentration of active species and the state of charge of the active species, in these solutions. As such, redox flow batteries may be used for large scale energy storage needs associated with wind farms and solar energy plants, for example, by scaling the size of the reservoir tanks and active species concentrations, accordingly. Redox flow cells also have the advantage of having their storage capacity being independent of their power. The power in a redox flow battery or cell is generally

determined by the size and number of electrochemical cells (sometimes referred to in total as a "stack") within the battery. Additionally, as redox flow batteries are being designed for electrical grid use, the voltages must be high. However, the voltage of a single redox flow electrochemical cell is generally less than 3 volts (difference in the potential of the half-cell reactions making up the cell). As such, hundreds of cells are required to be connected in series to generate voltages great enough to have practical utility and a significant amount of the cost of the cell or battery relates to the cost of the components making an individual cell. Additionally, as each cell is made of a variety of components, assembly cost can also be substantial.

Key components of a redox flow electrochemical cell and battery include the electrodes (e.g. anode and cathode), the ion permeable membrane disposed there between and the anode and cathode flow plates, e.g. an anode flow plate and a cathode flow plate. As the design of the cell is critical to the power output of a redox flow cell and battery, the materials selected for these components are critical to performance, as well as, the cost of the cell. Generally, each of these components is provided individually within a cell or battery as an individual component and this fact can lead to significant assembly cost for each cell.

Materials used for the electrodes may be based on carbon, e.g. graphite, which provides desirable catalytic activity for the oxidation/reduction reactions to occur and is electrically conductive to provide electron transfer to the flow plates. The electrode materials may be porous, to provide greater surface area for the oxidation/reduction reactions to occur. Porous electrodes may include porous electrically conductive materials. Porous electrodes may include carbon fiber based papers, felts, and cloths. Porous electrodes may also include porous dielectric materials that include at least one electrically conductive coating to enable electrically conductivity. Porous electrodes may also include polymer-electrically conductive particulate composites. When porous electrodes are used, the electrolytes may penetrate into the body of the electrode, access the additional surface area for reaction and thus increase the rate of energy generation per unit volume of the electrode. Also, as one or both of the anolyte and catholyte may be water based, i.e. an aqueous solution, there may be a need for the electrode to have a hydrophilic surface, to facilitate electrolyte permeation into the body of a porous electrode. Surface treatments may be used to enhance the hydrophilicity of the redox flow electrodes. This is in contrast to fuel cell electrodes which typically are designed to be hydrophobic, to prevent moisture from entering the electrode and corresponding catalyst layer/region, and to facilitate removal of moisture from the electrode region in, for example, a hydrogen/oxygen based fuel cell.

Typically, the monopolar anode flow plate and the monopolar cathode flow plate are electrically conductive and may be fabricated from metals or other electrically conductive materials, such as, an electrically conductive polymer or electrically conductive polymer composite. Significant cost may be incurred due to the cost of the materials and the costs associated with the fabrication of the plate, e.g. the formation of the at least one flow channel. The monopolar anode and cathode flow plates may be fabricated by a variety of techniques including machining (e.g. milling), molding (e.g. injection molding), embossing and combinations thereof.

The present disclosure provides unique monopolar plate-electrode assemblies that combine a flow plate substrate (cathode or anode) with a porous electrode material contained in at least a portion of the at least one flow channel of the flow plate substrate. In so doing, two layers of an electrochemical cell or battery may be combined into a single layer, which may reduce cell and/or battery assembly costs. Additionally, the bottom of the at least one flow channel of the monopolar plate-electrode assemblies of the present disclosure may intersect at least one via, that extends through the remaining thickness of the flow plate substrate, and an electrically conductive material is contained in at least a portion of the at least one via. The electrically conductive material is in electrical communication with the porous electrode material. As such, the monopolar plate-electrode assemblies of the present disclosure provide electrical communication between the first major surface and the second major surface of the flow plate substrate, through the porous electrode material and the electrically conductive material within the at least one via, i.e. the monopolar plate-electrode assemblies exhibit electrical communication through the thickness of the flow plate substrate. With this unique design, the flow plate substrate need not be fabricated from an expensive conductive material and may, in turn, be fabricated from an inexpensive and/or easily processed dielectric material, e.g. a dielectric polymer. However, this is not a limitation and the flow plate substrate may be fabricated from electrically conductive materials. The flow plate substrate, porous electrode material and electrically conductive material may form an integral structure and will be referred to as a monopolar plate-electrode assembly. The monopolar plate-electrode assembly may be used in an electrochemical cell and/or liquid flow battery.

The monopolar plate-electrode assembly may further include an electrically conductive layer adjacent the major surface of the flow plate substrate that does not include the at least one flow channel. Optionally, the monopolar plate-electrode assembly may further include an ion permeable membrane adjacent the major surface of the flow plate substrate that includes the at least one flow channel. Optionally, the monopolar plate- electrode assembly may further include a discontinuous transport protection layer adjacent the major surface of the flow plate substrate that includes the at least one flow channel. In embodiments that include the optional ion permeable membrane, the optional discontinuous transport protection layer may be disposed between the ion permeable membrane and the flow plate substrate. The discontinuous transport protection layer protects the ion permeable membrane from puncture by materials that comprise the porous electrode material, e.g.

carbon fibers, and thus prevents localized shorting. The term "transport" within the phrase "transport protection layer" refers to fluid transport within and/or through the protection layer. The monopolar plate-electrode assemblies are useful in the fabrication of liquid flow, e.g. redox flow, electrochemical cells and batteries. Liquid flow electrochemical cells and batteries may include cells and batteries having a single half-cell being a liquid flow type or both half-cells being a liquid flow type. The present disclosure further provides methods of fabricating monopolar plate assemblies useful in liquid flow electrochemical cells and batteries.

The present disclosure provides monopolar plate-electrode assemblies comprising (i) a flow plate substrate having a first major surface and an opposed second major surface in the x-y plane of the monopolar plate, wherein the first major surface includes at least one flow channel, allowing fluid flow in the x-y plane of the monopolar plate, the at least one flow channel is in fluid communication with a fluid inlet port and a fluid outlet port of the flow plate substrate, and wherein the flow plate substrate includes at least one via intersecting the bottom of the at least one flow channel and the second major surface of the flow plate substrate; (ii) a porous electrode material contained in at least a portion of the at least one flow channel; and (iii) an electrically conductive material contained in at least a portion of the at least one via, wherein the monopolar plate-electrode assemblies exhibit electrical communication through the thickness of the flow plate substrate and does not exhibit fluid communication through the thickness of the flow plate substrate. In some embodiments, the flow plate substrate is an electrically conductive flow plate substrate. In some embodiments, the flow plate substrate is a dielectric flow plate substrate. The at least one via may be a single via or a plurality of vias. In some embodiments, the electrically conductive material may be impervious to fluid. In some embodiments, the monopolar plate-electrode assemblies of the present disclosure further comprise an optional electrically conductive layer adjacent to and/or in contact with the second major surface of the flow plate substrate. The electrically conductive layer may be impervious to fluid. The porous electrode material, the electrically conductive material and/or the electrically conductive layer may include electrically conductive particulate, e.g. electrically conductive carbon particulate including, but not limited to, at least one of carbon particles, carbon flakes, carbon fibers, carbon dendrites, carbon nanotubes and branched carbon nanotubes; graphite forms of carbon may be particularly useful, as graphite may have improved stability in highly oxidative and reducing environments. In some embodiments, the porous electrode material, the electrically conductive material and/or the electrically conductive layer may include at least one of a metal film, an electrically conductive particulate and an electrically conductive polymer composite; the electrically conductive polymer composite may include polymer and the electrically conductive particulate. The electrically conductive particulate may include at least one of metal particulate, electrically conductive carbon particulate and electrically conductive polymer particulate. In some embodiments, the distal surface of the first major surface of the flow plate substrate may be free of porous electrode material and/or a conventional electrode, e.g. carbon fiber mat. In some embodiments, the distal surface of the second major surface of the flow plate substrate may be free of electrically conductive material. In some embodiments, at least a portion (up to and including all) of the distal surface of the first major surface of the flow plate substrate may include a layer of porous electrode material. In some embodiments, at least a portion (up to and including all) of the distal surface of the second major surface of the flow plate substrate may include a layer of electrically conductive material. If at least a portion of the distal surface of the first and/or second major surface of the flow plate substrate includes a layer of porous electrode material and/or a layer of electrically conductive material, the layer of porous electrode material and the layer of electrically conductive material may be considered to be part of the major surface of the flow plate substrate. In some embodiments, the thickness of the flow plate substrate may be from 0.025 cm to 3.2 cm. The monopolar plate-electrode assembly may include an, optional, ion permeable membrane disposed adjacent the first major surface of the flow plate substrate. The monopolar plate-electrode assembly may include an, optional, discontinuous transport protection layer disposed adjacent the first major surface of the flow plate substrate. Embodiments that contain an ion permeable membrane may further include a discontinuous transport protection layer disposed between the ion permeable membrane and the first major surface of the flow plate substrate.

FIGS. 1 A through ID and FIGS. 3 A through 3D show various, non-limiting, embodiments of flow plate substrates suitable for monopolar plate-electrode assemblies of the present disclosure and FIGS. 2A through 2D and FIGS. 4A through 4D show the corresponding exemplary monopolar plate-electrode assemblies utilizing the flow plate substrates of FIGS. 1 A through ID and FIGS. 3 A through 3D, respectively. FIG. 1 A is a schematic top view and FIG. IB is a schematic bottom view of exemplary flow plate substrate 10 according to one embodiment of the present disclosure. Flow plate substrate 10 has a first major surface 10a and an opposed second major surface 10b (see FIG. IB), at least one flow channel 20 with a bottom 20b (see FIG. 1C) in fluid communication with a fluid inlet port 30a (represented by the imaginary, dashed lines) and a fluid outlet port 30b

(represented by the imaginary, dashed lines) and includes at least one via 40 intersecting the channel bottom 20b of the at least one flow channel 20. In this exemplary embodiments, the at least one via 40 is a plurality of vias 40. The flow plate substrate has a front face lOff and a back face lObf. FIG. IB shows a schematic bottom view of the exemplary flow plate substrate 10 of FIG. 1 A and includes second major surface 10b and the at least one via 40. FIG. 1C shows a schematic cross-sectional side view of the exemplary flow plate substrate 10 of FIG. 1 A through line 1C. Flow plate substrate 10 of FIG. 1C includes first major surface 10a and second major surface 10b, at least one flow channel 20 having channel bottom 20b and a depth, D, a width, W, and at least one via 40, having a height, H, intersecting the channel bottom 20b of the at least one flow channel 20 and the second major surface 10b. FIG. ID is a schematic side view of the front face or back face (in this exemplary

embodiment, the flow plate substrate is symmetrical and the front face and back face views are identical) of the exemplary flow plate substrate 10 of FIG. 1 A. Flow plate substrate 10 of FIG. ID shows front face lOff or back face lObf and includes first major surface 10a and second major surface 10b and inlet port 30a of front face lOff or outlet port 30b of back face lObf. Flow plate substrate 10 has thickness, T.

FIGS. 2A through 2D are schematic views of an exemplary monopolar plate-electrode assembly 100 which includes the flow plate substrate 10 of FIGS. 1 A through ID, according to one exemplary embodiment of the present disclosure. FIG. 2A is a schematic top view, FIG. 2B is a schematic bottom view, FIG. 2C is a schematic cross-sectional side view, though line 2C of FIG. 2A, and FIG. 2D is a schematic side view of the front face or back face of the exemplary monopolar plate-electrode assembly 100. Monopolar plate-electrode assembly 100 includes flow plate substrate 10, as previously described. Flow plate substrate 10 has first major surface 10a and opposed second major surface 10b in the x-y plane of the monopolar plate. First major surface 10a includes at least one flow channel 20, allowing fluid flow in the x-y plane of the monopolar plate. Additionally, monopolar plate-electrode assembly 100 includes porous electrode material 50 contained in at least a portion of the at least one flow channel 20 and an electrically conductive material 60 contained in at least a portion of the at least one via 40, wherein the electrically conductive material 60 is in electrical communication with porous electrode material 50. Monopolar plate-electrode assembly 100 exhibits electrical communication between first major surface 10a and second major surface 10b, through the thickness of the flow plate substrate (z-axis), but does not exhibit fluid communication between first major surface 10a and second major surface 10b through the thickness of the flow plate substrate (z-axis). FIG. 2D shows a schematic side view of the front face lOOff or back face lOObf of the monopolar plate-electrode assembly 100 of FIG. 2A. In this exemplary embodiment, the monopolar plate-electrode assembly is symmetrical and the front face and back face views are identical. Monopolar plate-electrode assembly 100 may further include, optional, electrically conductive layer 70 adjacent to and in contact with the second major surface of the flow plate substrate. In some embodiments, the electrically conductive layer is impervious to fluid.

FIG. 3 A is a schematic top view and FIG. 3B is a schematic bottom view of exemplary flow plate substrate 11 according to one embodiment of the present disclosure. Flow plate substrate 11 has a first major surface 11a and an opposed second major surface 1 lb (see FIG. 3B), at least one flow channel 20 with a bottom 20b (see FIG. 3C) in fluid communication with a fluid inlet port 30a (represented by the imaginary, dashed lines) and a fluid outlet port 30b (represented by the imaginary, dashed lines) and includes at least one via 40 intersecting the channel bottom 20b of the at least one flow channel 20. In this exemplary embodiments, the at least one via 40 is a single via. The single via may span the entire width and length (x-y dimensions) of flow channel 20. The flow plate substrate has a front face 1 Iff and a back face 1 lbf FIG. 3B shows a schematic bottom view of the exemplary flow plate substrate 11 of FIG. 3A and includes second major surface 1 lb and the at least one via 40. FIG. 3C shows a schematic cross-sectional side view of the exemplary flow plate substrate 11 of FIG. 3A through line 3C. Flow plate substrate 11 of FIG. 3C includes first major surface 11a and second major surface 1 lb, at least one flow channel 20 having channel bottom 20b and a depth, D, a width, W, and at least one via 40, having a height, H, intersecting the channel bottom 20b of the at least one flow channel 20 and the second major surface 1 lb. FIG. 3D is a schematic side view of the front face or back face (in this exemplary embodiment, the flow plate substrate is symmetrical and the front face and back face views are identical) of the exemplary flow plate substrate 11 of FIG. 3A. Flow plate substrate 11 of FIG. 3D shows front face 1 Iff or back face 1 lbf and includes first major surface 11a and second major surface 1 lb and inlet port 30a of front face 1 Iff or outlet port 30b of back face 1 lbf. Flow plate substrate 11 has thickness, T.

FIGS. 4A through 4D are schematic views of an exemplary monopolar plate-electrode assembly 101 which includes the flow plate substrate 11 of FIGS. 3A through 3D, according to one exemplary embodiment of the present disclosure. FIG. 4A is a schematic top view,

FIG. 4B is a schematic bottom view, FIG. 4C is a schematic cross-sectional side view, though line 4C of FIG. 4A, and FIG. 4D is a schematic side view of the front face or back face of the exemplary monopolar plate-electrode assembly 101. Monopolar plate-electrode assembly 101 includes flow plate substrate 11, as previously described. Flow plate substrate 11 has first major surface 11a and opposed second major surface 1 lb in the x-y plane of the monopolar plate. First major surface 11a includes at least one flow channel 20, allowing fluid flow in the x-y plane of the monopolar plate. Additionally, monopolar plate-electrode assembly 101 includes porous electrode material 50 contained in at least a portion of the at least one flow channel 20 and an electrically conductive material 60 contained in at least a portion of the at least one via 40, wherein the electrically conductive material 60 is in electrical communication with porous electrode material 50. Monopolar plate-electrode assembly 101 exhibits electrical communication between first major surface 11a and second major surface 1 lb, through the thickness of the flow plate substrate, but does not exhibit fluid communication between first major surface 11a and second major surface 1 lb through the thickness of the flow plate substrate. FIG. 4D shows a schematic side view of the front face lOlff or back face lOlbf of the monopolar plate-electrode assembly 101 of FIG. 1 A. In this exemplary embodiment, the monopolar plate-electrode assembly is symmetrical and the front face and back face views are identical. Monopolar plate-electrode assembly 101 may further include, optional, electrically conductive layer 70 adjacent to and in contact with the second major surface of the flow plate substrate. In some embodiments, the electrically conductive layer is impervious to fluid.

In the monopolar plate-electrode assemblies of the present disclosure, the porous electrode material combined with the electrically conductive material in electrical communication therewith enable the monopolar-plate electrode assemblies to have electrical communication through the thickness of the flow plate substrate (between the first major surface and the second major surface of the flow plate substrate). This may be particularly beneficial when the flow plate substrate is a dielectric flow plate substrate. In some embodiments, the electrically conductive material is impervious to fluid. As such, in some embodiments, the fluid impervious electrically conductive material inhibits fluid

communication between the first major surface and the second major surface of the flow plate substrate, through the thickness of the flow plate substrate, i.e. the monopolar plate electrode assembly does not exhibit fluid communication through the thickness of the flow plate substrate. In some embodiments, wherein the electrically conductive material is not impervious to fluid and cannot prevent fluid communication between the first and second major surface, through the thickness of the flow plate substrate, the optional electrically conductive layer, which is impervious to fluid, may be used to inhibit fluid communication between the first major surface and the second major surface of the flow plate substrate.

FIG. 4C-1 is a schematic cross-sectional side view of an exemplary monopolar plate- electrode assembly 101-1, similar to monopolar plate-electrode assembly 101 of FIG. 4C, except monopolar plate-electrode assembly 101-1 further includes an ion permeable membrane 80 adjacent to first major surface 1 la of flow plate substrate 11. In some embodiments, as shown in FIG. 4C-1, ion permeable membrane 80 is adjacent to and in contact with first major surface 1 la of flow plate substrate 11. Any of the monopolar plate- electrode assemblies of the present disclosure, e.g. monopolar plate-electrode assemblies 100 and 101, may include an ion permeable membrane adjacent to the first major surface of the flow plate substrate.

FIG. 4C-2 is a schematic cross-sectional side view of an exemplary monopolar plate- electrode assembly 101-2, similar to monopolar plate-electrode assembly 101 of FIG. 4C, except monopolar plate-electrode assembly 101-2 further includes a discontinuous transport protection layer 90 adjacent to first major surface 1 la of flow plate substrate 11. In some embodiments, as shown in FIG. 4C-2, discontinuous transport protection layer 90 is adjacent to and in contact with first major surface 1 la of flow plate substrate 11. Any of the monopolar plate-electrode assemblies of the present disclosure, e.g. monopolar plate- electrode assemblies 100 and 101, may include a discontinuous transport protection layer adjacent to the first major surface of the flow plate substrate.

FIG. 4C-3 is a schematic cross-sectional side view of an exemplary monopolar plate- electrode assembly 101-3, similar to monopolar plate-electrode assembly 101 of FIG. 4C, except monopolar plate-electrode assembly 101-3 further includes an ion permeable membrane 80 adjacent to first major surface 1 la of flow plate substrate 11 and a discontinuous transport protection layer 90 disposed between ion permeable membrane 80 and first major surface 1 la of flow plate substrate 11. In some embodiments, as shown in FIG. 4C-3, discontinuous transport protection layer 90 is adjacent to and in contact with first major surface 1 la of flow plate substrate 11 and ion permeable membrane 80 is adjacent to and in contact with discontinuous transport protection layer 90. Any of the monopolar plate- electrode assemblies of the present disclosure, e.g. monopolar plate-electrode assemblies 100 and 101, may include an ion permeable membrane adjacent to the first major surface of the flow plate substrate and a discontinuous transport protection layer disposed between the ion permeable membrane and the first major surface of the flow plate substrate.

In some embodiments of the monopolar plate-electrode assemblies of the present disclosure, an ion permeable membrane may be adhered to the first major surface of the flow plate substrate of the monopolar plate-electrode assembly, the ion permeable membrane thereby being integral to and part of the monopolar plate-electrode assembly. In some embodiments, the electrically conductive layer may be adhered to the second major surface of the monopolar plate-electrode assembly, the electrically conductive layer thereby being integral to and part of the monopolar plate-electrode assembly. In some embodiments of the monopolar plate-electrode assembly of the present disclosure, a discontinuous transport protection layer may be adhered to the first major surface of the flow plate substrate, the discontinuous transport protection layer thereby being integral to and part of the monopolar plate-electrode assembly. Embodiments which include a discontinuous transport protection layer adhered to the first major surface of the flow plate substrate, may further include an ion permeable membrane adhered to the exposed surface of the discontinuous transport protection layer, the ion permeable membrane thereby being integral to and part of the monopolar plate-electrode assembly. Substrates may be directly adhered to one another without the aid of an additional adhesive or substrates may be adhered to one another through the use of conventional adhesives.

Flow Plate Substrate

The flow plate substrate of the present disclosure may be an electrically conductive flow plate substrate or a dielectric flow plate substrate, i.e. a non-electrically conductive flow plate substrate. Fabrication of the flow plate substrate may include known techniques in the art and the fabrication techniques may be selected based on the material of the flow plate substrate. In some embodiments, the flow plate substrate along with the at least one flow channel and/or the at least one via of the flow plate substrate may be formed in a single fabrication step, e.g. molding or insert molding, to form a flow pate substrate, or may be formed in multiple steps, e.g. calendaring, extruding and/or molding to form a solid flow plate substrate of the desired thickness followed by one or more machining steps to form the at least one flow channel and/or the at least one via. Combinations of conventional machining techniques may be used to form the flow plate substrate. Combinations of one or more conventional machining techniques and conventional molding, calendaring and/or extrusion techniques may also be used to form the flow plate substrate. The at least one flow channel and the at least one via of the flow plate substrate may be formed in the flow plate substrate using conventional machining techniques including, but not limited to, milling, sawing, boring, drilling, turning, laser cutting, water jet cutting and the like. Conventional molding techniques include pressing; embossing; molding, e.g. injection molding, insert molding and compression molding; and the like. In some embodiments, the electrically conductive material contained in at least a portion of the at least one via of the flow plate substrate is included in the flow plates substrate simultaneously while forming the at least one via. For example, if insert injection molding of a polymer or polymer composite is used to form the flow plate substrate, a plurality of electrically conductive pins, e.g. metal pins, may be placed in the mold prior to injection of the polymer into the mold. The at least one via, e.g. a plurality of vias in this example, of the flow plate substrate is formed by the polymer flowing around the plurality of electrically conductive pins. The plurality of vias are simultaneous filled by the electrically conductive material, i.e. the plurality of pins. In embodiments where the plurality of pins are integral to the mold, the pins may be removed from the flow plate substrate, leaving a plurality of vias. The pins may have a diameter or greatest dimension with respect to their cross-section of between 0.1 mm and 10 mm, between 0.1 mm and 5 mm, between 0.1 mm and 1 mm, between 0.3 mm and 10 mm, between 0.3 mm and 5 mm, between 0.3 mm and 1 mm, between 0.5 mm and 10 mm, between 0.5 mm and 5 mm or even between 0.5 mm and 1 mm.

The dimensions, length, width and thickness, of the flow plate substrate are not particularly limited. In some embodiments, the thickness, T, (z-axis dimension, relative to FIGS. 1A-1D, for example) of the flow plate substrate may be from 0.025 cm to 3.2 cm, from 0.025 cm to 2.2 cm, from 0.025 cm to 1.2 cm, from 0.05 cm to 3.2 cm, from 0.05 cm to 2.2 cm, from 0.05 cm to 1.2 cm, from 0.1 cm to 3.2 cm, from 0.1 cm to 2.2 cm, or even from 0.1 cm to 1.2 cm. In some embodiments, the length (y-axis dimension relative to FIGS. 1A-1D, for example) of the flow plate substrate may be from 1 cm to 160 cm, from 1 cm to 120 cm, from 1 cm to 80 cm, from 10 cm to 160 cm, from 10 cm to 120 cm, from 10 cm to 80 cm, from 20 cm to 160 cm, from 20 cm to 120 cm, or even from 20 cm to 80 cm. In some embodiments, the width (x-axis dimension, relative to FIGS. 1 A-ID, for example) of the flow plate substrate may be from 1 cm to 160 cm, from 1 cm to 120 cm, from 1 cm to 80 cm, from 10 cm to 160 cm, from 10 cm to 120 cm, from 10 cm to 80 cm, from 20 cm to 160 cm, from 20 cm to 120 cm, or even from 20 cm to 80 cm.

The dimensions of the flow channel are not particularly limited, except by the dimension of the flow plate substrate, as the at least one flow channel must be capable of being contained within the dimensions of the flow plate substrate. It is inherent in the description of the flow plate substrate that the depth of the at least one flow channel, D, is less than the thickness, T, of the flow plate substrate. In some embodiments, the depth, D, of the at least one flow channel may be from 0.020 cm to 3 cm, from 0.020 cm to 2 cm, from 0.020 cm to 1 cm, from 0.04 cm to 3 cm, from 0.04 cm to 2 cm, from 0.04 cm to 1 cm, from 0.08 cm to 3 cm, from 0.08 cm to 2 cm, or even from 0.08 cm to 1 cm. In some embodiments, the width, W, of the at least one flow channel may be from may be from 0.1 cm to 3 cm, from 0.1 cm to 2 cm, from 0.1 cm to 1 cm, from 0.2 cm to 3 cm, from 0..2 cm to 2 cm, from 0..2 cm to 1 cm, from 0.3 cm to 3 cm, from 0.3 cm to 2 cm, or even from 0.3 cm to 1 cm. In some embodiments, the width, W of the at least one flow channel may be from 1 cm to 200 cm, from 1 cm to 150 cm from 1 cm to 100 cm or even from 1 cm to 50 cm. The at least one flow channel may be a serpentine flow channel or it may not be a serpentine flow channel.

The size, i.e. dimensions, shape, number (when a plurality of vias are used) and areal density (when a plurality of vias are used) of the at least one via is not particularly limited. The dimensions of the at least one via are not particularly limited, except by the dimension of the flow plate substrate, as the at least one via must be capable of being contained within the dimensions of the flow plate substrate. In some embodiments, the height, H, of the at least one via may be from may be from 0.020 cm to 3 cm, from 0.020 cm to 2 cm, from 0.020 cm to 1 cm, from 0.04 cm to 3 cm, from 0.04 cm to 2 cm, from 0.04 cm to 1 cm, from 0.08 cm to 3 cm, from 0.08 cm to 2 cm, or even from 0.08 cm to 1 cm. In some embodiments, the at least one via is a single via, as shown in FIGS, 3 A-3D, for example. In some embodiments, the at least one via is a plurality of vias, as shown in FIGS, 1 A-ID, for example. In some embodiments, the plurality of vias include from 2 to 2000000 vias, from 2 to 100000 vias, from 2 to 10000 vias, from 2 to 1000 vias, from 2 to 500 vias, from 2 to 300 vias, from 2 to 100 vias, from 10 to 2000000 vias, from 10 to 100000 vias , from 10 to 10000 vias, from 10 to 1000 vias, from 10 to 500 vias, from 10 to 300 vias, from 10 to 100 vias, from 25 to 2000000 vias, from 25 to 100000 vias, from 25to 10000 vias, from 25 to 1000 vias, from 25 to 500 vias, from 25 to 300 vias, or even from 25 to 100 vias. In some embodiments, the ratio of the surface area of the at least one via (e.g. the sum of the projected surface of a plurality of vias, if a plurality of vias are used) projected onto the surface (first or second major surface) of the flow plate substrate, to the surface area of the flow plate substrate (first or second major surface) is from 0.01 to 0.90, from, 0.01 to 0.80 from 0.01 to 0.70, from 0.05 to 0.90, from, 0.05 to 0.80 from 0.05 to 0.70, from 0.1 to 0.90, from a, 0.1 to 0.80 from 0.1 to 0.70, from 0.2 to 0.90, from, 0.2 to 0.80 from 0.2 to 0.70, from 0.3 to 0.90, from, 0.3 to 0.80 ore even from 0.3 to 0.70. In some embodiments, the width of the individual vias, when a plurality of vias are used is from 5 microns to 5 mm, from 5 microns to 2.5 mm, from 5 microns from 1 mm, from 5 microns to 500 microns, from 25 microns to 5 mm, from about 25 microns to 2.5 mm, from 25 microns to 1 mm, from 25 microns to 500 microns, from 50 microns to 5 mm, from 50 microns to 2.5 mm, from 50 microns to 1 mm, from 50 microns to 500 microns, from 100 microns to 5 mm, from 100 microns to 2.5 mm, from 100 microns to 1 mm or even from 5 microns to 100 microns. When a plurality of vias are used, the height of each individual via may be the same or may vary. The shape of the via may include at least one of a cube, cuboid (rectangular prism), cylinder, triangular prism, hexagonal prism, pyramidal, hemispheroid, pyramidal, truncated pyramidal, conical, truncated conical and the like. Combinations of shapes may be used.

The dimensions of the inlet and outlet ports are not particularly limited, except by the dimensions of the flow plate substrate. The inlet and outlet ports enable fluid, e.g. anolyte or catholyte, to access the at least one flow channel. The inlet and outlet ports may supply fluid to more than one flow channel. Multiple fluid inlet and outlet ports may be used. The location of the inlet and outlet ports within the flow plate substrate are selected based on the overall design of the flow plate substrate with respect to its integration into an

electrochemical cell or battery.

The electrically conductive flow plate substrate may include at least one of a metal, electrically conductive carbon, electrically conductive polymer and electrically conductive polymer composite. Useful metals for the electrically conductive flow plate substrate include, but are not limited to, at least one of silver, copper, gold, aluminum, magnesium, molybdenum, iridium, tungsten, zinc, lead, cobalt, nickel, manganese, ruthenium, lithium, iron, tin, platinum, palladium, tantalum, chromium, antimony, vanadium, titanium, zirconium, bismuth, indium, gallium, and cerium. Noble metals may be particularly useful, due to their stability. Combinations of metal may be used, e.g. metal alloys. Metal laminates may be used. The electrically conductive flow plate substrate may be a metal sheet, formed by known techniques. The at least one flow channel and the at least one via of the electrically conductive flow plate substrate may be formed in the metal sheet using conventional machining techniques discussed previously. In some embodiments, the electrically conductive flow plate substrate along with the at least one flow channel and/or the at least one via of the electrically conductive flow plate substrate may be formed by molding of a liquid metal followed by cooling to solidify the metal.

Useful electrically conductive carbon for the electrically conductive flow plate substrate includes, but is not limited to, carbon fiber sheets. In some embodiments, the carbon fiber sheets may include an electrically conductive core of a non-carbon fiber material. The carbon fiber sheets may include carbon fiber woven substrates and/or carbon fiber non-woven substrates. The carbon fiber woven substrates and/or carbon fiber non- woven substrates may be polymer-carbon fiber sheet composites or laminates, wherein the carbon fiber sheet is imbibed with a liquid polymer or liquid polymer precursor solution, which is later solidified via cooling or curing, for example, to form a solid polymer-carbon fiber sheet composite. The at least one flow channel and the at least one via of the electrically conductive flow plate substrate may be formed in the polymer-carbon fiber sheet composites using the previously described conventional machining techniques. Molding techniques may be used to form the at least one flow channel and/or the at least one via of the polymer-carbon fiber sheet composite during the formation thereof. The polymer of the polymer-carbon fiber sheet composite may include at least one of a thermoplastic and thermoset. The polymer selected for the polymer-carbon fiber sheet composite should have good chemical resistance to the anolyte and/or catholyte to which it will be exposed.

Useful electrically conductive polymer for the electrically conductive flow plate substrate includes, but is not limited to, at least one of polyaniline, polypyrrole and polyacetylene. The electrically conductive polymer may be used as a single component or may be used in a dielectric polymer-electrically conductive polymer composite or laminate.

Useful electrically conductive polymer composite for the electrically conductive flow plate substrate includes an electrically conductive particulate and a polymer, e.g. a dielectric polymer. In some embodiments, the electrically conductive particulate is dispersed in the polymer. The electrically conductive particulate in the electrically conductive polymer composite enables the composite to be electrically conductive, particularly when the polymer is a dielectric polymer. When the polymer is a dielectric polymer, the amount of electrically conductive particulate required to make the electrically conductive polymer composite electrically conductive depends on the particulate type and the material comprising the electrically conductive particulate. High aspect ratio electrically conductive particulate, e.g. electrically conductive fiber, may require a lower amount of particulate to form an electrically conductive composite compared to a low aspect ratio particulate, e.g. an electrically conductive spherical particle. A particulate comprising a highly electrically conductive material, e.g. silver, may require a lower amount of particulate to form an electrically conductive composite compared to a less electrically conductive material, e.g. iron. In some embodiments, the amount of electrically conductive particulate in the electrically conductive polymer composite may be between 5 percent by weight and 95 percent by weight, between 15 percent by weight and 95 percent by weight, between 25 percent by weight and 95 percent by weight, between 5 percent by weight and 85 percent by weight, between 15 percent by weight and 85 percent by weight, between 25 percent by weight and 85 percent by weight, between 5 percent by weight and 75 percent by weight, between 15 percent by weight and 75 percent by weight, or even between 25 percent by weight and 75 percent by weight. In some embodiments, the amount of polymer in the electrically conductive polymer composite may be between 5 percent by weight and 95 percent by weight, between 5 percent by weight and 85 percent by weight, between 5 percent by weight and 75 percent by weight, between 15 percent by weight and 95 percent by weight, between 15 percent by weight and 85 percent by weight, between 15 percent by weight and 75 percent by weight, between 25 percent by weight and 95 percent by weight, between 25 percent by weight and 85 percent by weight, or even between 25 percent by weight and 75 percent by weight. In some embodiments, it may be desirable for the electrically conductive polymer composite to include from 50 percent to 90 percent by weight polymer or even from 60 percent to 90 percent by weight polymer, due to at least one of lower cost, lower weight and ease of processing.

The electrically conductive particulate may include at least one of a metal particulate, electrically conductive carbon particulate and electrically conductive polymer particulate. The metal of the metal particulate may include, but is not limited to at least one of silver, copper, gold, aluminum, magnesium, molybdenum, iridium, tungsten, zinc, lead, cobalt, nickel, manganese, ruthenium, lithium, iron, tin, platinum, palladium, tantalum, chromium, antimony, vanadium, titanium, zirconium, bismuth, indium, gallium, and cerium. Noble metals may be particularly useful, due to their stability. Combinations of metal may be used, e.g. metal alloys. The electrically conductive carbon particulate may include, but is not limited to, at least one of carbon particles, carbon flakes, carbon fibers, carbon dendrites, carbon nanotubes and branched carbon nanotubes; combinations may be used. In some embodiments, the electrically conductive carbon particulate may include at least one of graphite particles, graphite flakes, graphite fibers and graphite dendrites; combinations may be used. The electrically conductive polymer particulate includes, but is not limited to, at least one of polyaniline, polypyrrole and polyacetylene.

Throughout this disclosure, the term "particulate", is meant to include particles, flakes, fibers, dendrites and the like. Particulate particles generally include particulates that have aspect ratios of length to width and length to thickness both of which are between 1 and 5. In some embodiments, the particle size may be from between 0.001 microns to 100 microns, from between 0.001 microns to 50 microns, from between 0.001 to 25 microns, from between 0.001 microns to 10 microns, from 0.001 microns to 1 microns, from between 0.01 microns and 100 microns, from between 0.01 microns to 50 microns, from between 0.01 to 25 microns, from between 0.01 microns to 10 microns, from 0.01 microns to 1 microns, from between 0.05 microns to 100 microns, from between 0.05 microns to 50 microns, from between 0.05 to 25 microns, from between 0.05 microns to 10 microns, from 0.05 microns to 1 microns, from between 0.1 microns and 100 microns, from between 0.1 microns to 50 microns, from between 0.1 to 25 microns, from between 0.1 microns to 10 microns, or even from between 0.1 microns to 1 microns. Particles may be spheroidal in shape.

Particulate flakes generally include particulates that have a length and a width each of which is significantly greater than the thickness of the flake. A flake includes particulates that have aspect ratios of length to thickness and width to thickness each of which is greater than 5. There is no particular upper limit on the length to thickness and width to thickness aspect ratios of a flake. Both the length to thickness and width to thickness aspect ratios of the flake may be between 6 and 1000, between 6 and 500, between 6 and 100, between 6 and 50, between 6 and 25, between 10 and 500, between 10 and 150, between 10 and 100, or even between 10 and 50. In some embodiments, the length and width of the flake may each be from between 0.001 microns to 50 microns, from between 0.001 to 25 microns, from between 0.001 microns to 10 microns, from 0.001 microns to 1 microns, from between 0.01 microns to 50 microns, from between 0.01 to 25 microns, from between 0.01 microns to 10 microns, from 0.01 microns to 1 microns, from between 0.05 microns to 50 microns, from between 0.05 to 25 microns, from between 0.05 microns to 10 microns, from 0.05 microns to 1 microns, from between 0.1 microns to 50 microns, from between 0.1 to 25 microns, from between 0.1 microns to 10 microns, or even from between 0.1 microns to 1 microns. Flakes may be platelet in shape. Particulate dendrites include particulates having a branched structure. The particle size of the dendrites may be the same as those disclosed for the particulate particles, discussed above.

Particulate fibers generally include particulates that have aspect ratios of the length to width and length to thickness both of which are greater 10 and a width to thickness aspect ratio less than 5. For a fiber having a cross sectional area that is in the shape of a circle, the width and thickness would be the same and would be equal to the diameter of the circular cross-section. There is no particular upper limit on the length to width and length to thickness aspect ratios of a fiber. Both the length to thickness and length to width aspect ratios of the fiber may be between 10 and 1000000, between 10 and 100000, between 10 and 1000, between 10 and 500, between 10 and 250, between 10 and 100, between 10 and 50, between 20 and 1000000, between 20 and 100000, between 20 and 1000, between 20 and 500, between 20 and 250, between 20 and 100 or even between 20 and 50. In some embodiments, the width and thickness of the fiber may each be from between 0.001 to 100 microns, from between 0.001 microns to 50 microns, from between 0.001 to 25 microns, from between 0.001 microns to 10 microns, from 0.001 microns to 1 microns, from between 0.01 to 100 microns, from between 0.01 microns to 50 microns, from between 0.01 to 25 microns, from between 0.01 microns to 10 microns, from 0.01 microns to 1 microns, from between 0.05 to 100 microns, from between 0.05 microns to 50 microns, from between 0.05 to 25 microns, from between 0.05 microns to 10 microns, from 0.05 microns to 1 microns, from between 0.1 to 100 microns, from between 0.1 microns to 50 microns, from between 0.1 to 25 microns, from between 0.1 microns to 10 microns, or even from between 0.1 microns to 1 microns. In some embodiments the thickness and width of the fiber may be the same.

The polymer of the polymer-carbon fiber sheet composite and the polymer of the electrically conductive polymer composite is not particularly limited. However, in order to ensure long term stability of the polymer in the anolyte and/or catholyte liquids it may be exposed to during use, the polymer may be selected to have good chemical resistance to the anolyte and/or catholyte, including the associated solvent, oxidizing/reducing active species, salts and/or other additives included therein. In some embodiments, the polymer may include at least one of a thermoplastic and thermoset. In some embodiments, the polymer may include a thermoplastic. In some embodiments, the polymer may include a thermoset. In some embodiments, the polymer may consists essentially of a thermoplastic. In some embodiments, the polymer may consists essentially of a thermoset. Thermoplastics may include thermoplastic elastomers. A thermoset may include a B-stage thermoset, e.g. a B- stage thermoset after final cure. In some embodiments, the polymer may include at least one of a thermoplastic and a B-stage thermoset. In some embodiments, the polymer may consist essentially of a B-stage thermoset, e.g. a B-stage thermoset after final cure. In some embodiments, polymer (polymer type) includes, but is not limited to, at least one of epoxy resin, phenolic resin, ionic polymer, polyurethane, urea-formadehyde resin, melamine resin, polyester, e.g. polyethylene terephthalate, polyamide, polyether, polycarbonate, polyimide, polysulphone, polyphenylene oxide, polyacrylate, polymethacrylate, polyolefin, e.g.

polyethylene and polypropylene, styrene and styrene based random and block copolymer, e.g. styrene-butadiene- styrene, chlorinated polymer, e.g. polyvinyl chloride, and fluorinated polymer, e.g. polyvinylidene fluoride and polytetrafluoroethylene. In some embodiments, the polymer may be at least one of polyurethane, polyester, polyamide, polyether, polycarbonate, polyimide, polysulphone, polyphenylene oxide, polyacrylate, polymethacrylate, polyolefin, styrene and styrene based random and block copolymer, chlorinated polymer, and fluorinated polymer. The polymer may be a polymer blend. In some embodiments, the polymer blend may include at least two polymers selected from the polymers of the present disclosure.

In some embodiments, the polymer-carbon fiber sheet composite and/or the electrically conductive polymer composite may include non-electrically conductive inorganic material, e.g. and non-electrically conductive inorganic filler, e.g. a metal oxide such as silica, alumina, zirconia and the like and combinations thereof. In some embodiments, polymer-carbon fiber sheet composite and the electrically conductive polymer composite includes from 0.5 percent to 20 percent, from 0.5 percent to 15 percent, from 0.5 percent to 10 percent, or even from 0.5 percent to 5 percent by weight non-electrically conductive inorganic filler. Non-electrically conductive inorganic filler may be used to improve various mechanical properties, e.g. tensile strength, toughness and/or flexing or bending strength.

In some embodiments, the polymer of the polymer-carbon fiber sheet composite and/or the electrically conductive polymer composite has a softening temperature from 50 degrees centigrade to 400 degrees centigrade, from 50 degrees centigrade to 350 degrees centigrade, from 50 degrees centigrade to 300 degrees centigrade or even from 50 degrees centigrade to 250 degrees centigrade. In some embodiments, the polymer of the polymer- carbon fiber sheet composite and/or the electrically conductive polymer composite is non- tacky at 25 degrees centigrade, 30 degrees centigrade, 40 degree centigrade, or even 50 degrees centigrade. In some embodiments, the polymer of the polymer-carbon fiber sheet composite and/or the electrically conductive polymer composite contains from 0 percent to 15 percent by weight, from 0 percent to 10 percent by weight, from 0 percent to 5 percent by weight, from 0 percent to 3 percent by weight, from 0 percent to 1 percent by weight or even substantially 0 percent by weight pressure sensitive adhesive. Low modulus and/or highly viscoelastic materials, such as a pressure sensitive adhesive, may flow during use, due to the compression forces within an electrochemical cell or liquid flow battery, and may make it difficult to obtain the desired separation between cell or battery components. In some embodiments the modulus, e.g. Young's modulus, of the polymer of the polymer-carbon fiber sheet composite and/or the electrically conductive polymer composite may be from 0.010 GPa to 10 GPa, from 0.1 GPa to 10 GPa, from 0.5 GPa to 10 GPa, from 0.010 GPa to 5 GPa, from 0.1 GPa to 5 GPa or even from 0.5 GPa to 5 GPa.

Dielectric flow plate substrate, i.e. a non-electrically conductive flow plate substrate, may include at least one of a dielectric polymer and a dielectric inorganic material. In some embodiments, the dielectric flow plate substrate includes at least one dielectric polymer. Dielectric polymer may be particularly useful, due to at least one of low cost, low weight and ease of processing.

Useful dielectric inorganic material include, but is not limited to, metal oxides. In some embodiments, the metal oxides of the dielectric inorganic material include, but are not limited to at least one of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, cerium oxide, and the like. In some embodiments, the amount of dielectric inorganic material in the dielectric flow plate substrate may be between 15 percent by weight and 100 percent by weight, between 25 percent by weight and 100 percent by weight, between 35 percent by weight and 100 percent by weight, between 50 percent by weight and 100 percent by weight, between 70 percent by weight and 100 percent by weight, between 85 percent by weight and 100 percent by weight, or even between 90 percent by weight and 100 percent by weight.

The dielectric polymer of the dielectric flow plate substrate is not particularly limited. However, in order to ensure long term stability of the dielectric polymer in the anolyte and/or catholyte liquids it may be exposed to during use, the dielectric polymer may be selected to have good chemical resistance to the anolyte and/or catholyte, including the associated solvent, oxidizing/reducing active species, salts and/or other additives included therein. In some embodiments, the dielectric polymer may include at least one of a dielectric

thermoplastic and dielectric thermoset. In some embodiments, the dielectric polymer may include a dielectric thermoplastic. In some embodiments, the dielectric polymer may include a dielectric thermoset. In some embodiments, the dielectric polymer may consists essentially of a dielectric thermoplastic. Dielectric thermoplastics may include dielectric thermoplastic elastomers. In some embodiments, the dielectric polymer may consists essentially of a dielectric thermoset. A dielectric thermoset may include a B-stage dielectric thermoset, e.g. a B-stage dielectric thermoset after final cure. In some embodiments, the dielectric polymer (dielectric polymer type) may include at least one of a dielectric thermoplastic and a B-stage dielectric thermoset. In some embodiments, the dielectric polymer may consist essentially of a B-stage dielectric thermoset, e.g. a B-stage dielectric thermoset after final cure. In some embodiments, dielectric polymer includes, but is not limited to, at least one of epoxy resin, phenolic resin, ionic polymer, polyurethane, urea-formadehyde resin, melamine resin, polyester, e.g. polyethylene terephthalate, polyamide, polyether, polycarbonate, polyimide, polysulphone, polyphenylene oxide, polyacrylate, polymethacrylate, polyolefin, e.g.

polyethylene and polypropylene, styrene and styrene based random and block copolymer, e.g. styrene-butadiene-styrene, chlorinated polymer, e.g. polyvinyl chloride, and fluorinated polymer, e.g. polyvinylidene fluoride and polytetrafluoroethylene. In some embodiments, the dielectric polymer may be at least one of polyurethane, polyester, polyamide, polyether, polycarbonate, polyimide, polysulphone, polyphenylene oxide, polyacrylate,

polymethacrylate, polyolefin, styrene and styrene based random and block copolymer, chlorinated polymer, and fluorinated polymer. The dielectric polymer may be a dielectric polymer blend or dielectric polymer composite. In some embodiments, the dielectric polymer blend and/or composite may include at least two dielectric polymers selected from the dielectric polymers of the present disclosure.

In some embodiments, the amount of dielectric polymer in the dielectric flow plate substrate may be between 15 percent by weight and 100 percent by weight, between 25 percent by weight and 100 percent by weight, between 35 percent by weight and 100 percent by weight, between 50 percent by weight and 100 percent by weight, between 70 percent by weight and 100 percent by weight, between 85 percent by weight and 100 percent by weight, or even between 90 percent by weight and 100 percent by weight.

The dielectric polymer may contain other fillers, e.g. inorganic materials, including but not limited to inorganic metal oxides. The dielectric polymer may even include small amounts; less than 5 percent by weight, less than 4 percent by weight, less than 3 percent by weight, less than 2 percent by weight or even less than 1 percent by weight; of electrically conductive material, so long as the addition of the electrically conductive material does not significantly alter the dielectric property of the dielectric polymer.

In some embodiments, the dielectric polymer of the dielectric flow plate substrate has a softening temperature from 50 degrees centigrade to 400 degrees centigrade, from 50 degrees centigrade to 350 degrees centigrade, from 50 degrees centigrade to 300 degrees centigrade or even from 50 degrees centigrade to 250 degrees centigrade. In some

embodiments, the polymer of the polymer-carbon fiber sheet composite and/or the

electrically conductive polymer composite is non-tacky at 25 degrees centigrade, 30 degrees centigrade, 40 degree centigrade, or even 50 degrees centigrade In some embodiments the modulus, e.g. Young's modulus, of the dielectric polymer may be from 0.010 GPa to 10 GPa, from 0.1 GPa to 10 GPa, from 0.5 GPa to 10 GPa, from 0.010 GPa to 5 GPa, from 0.1 GPa to 5 GPa, from 0.5 GPa to 5 GPa, from 0.010 GPa to 3 GPa, from 0.1 GPa to 3 GPa, or even from 0.5 GPa to 3 GPa. Porous Electrode Material and Electrically Conductive Material

The porous electrode material of the present disclosure is electrically conductive and the porosity facilitates the oxidation/reduction reaction that occur therein by increasing the amount of active surface area for reaction to occur, per unit volume of electrode, and by allowing the anolyte and catholyte to permeate into the porous regions and access this additional surface area.

The porous electrode material and/or the electrically conductive material may include at least one of woven and nonwoven fiber mats, woven and nonwoven fiber papers, felts and cloths (fabrics). In some embodiments, the porous electrode material and/or the electrically conductive material includes carbon fiber. The carbon fiber may include, but is not limited to, glass like carbon, amorphous carbon, graphite, graphene, carbon nanotubes and graphite. Particularly useful porous electrode material and/or the electrically conductive material include carbon papers, carbon felts and carbon cloths (fabrics), e.g. graphite papers, graphite felts and graphite cloths. In some embodiment, the porous electrode material and/or the electrically conductive material includes at least one of carbon paper, carbon felt and carbon cloth.

In some embodiments, the porous electrode material and/or the electrically conductive material may include at least one of a metal film, an electrically conductive particulate and an electrically conductive polymer composite; the electrically conductive polymer composite may include polymer and the electrically conductive particulate. The electrically conductive particulate may include at least one of metal particulate, electrically conductive carbon particulate and electrically conductive polymer particulate.

In some embodiments, the porous electrode material and/or the electrically conductive material includes a metal material, e.g. a porous metal material. The metal material may be a metal film. The metal of the metal material may include, but is not limited to, at least one of silver, copper, gold, aluminum, magnesium, molybdenum, iridium, tungsten, zinc, lead, cobalt, nickel, manganese, ruthenium, lithium, iron, tin, platinum, palladium, tantalum, chromium, antimony, vanadium, titanium, zirconium, bismuth, indium, gallium, and cerium. Combinations of metal may be used, e.g. metal alloys. Noble metals may be particularly useful, due to their stability.

In some embodiments, the porous electrode material and/or the electrically conductive material includes electrically conductive particulate, e.g. electrically conductive carbon particulate. In some embodiments, the porous electrode material and/or the electrically conductive material includes from 30 percent to 100 percent, from 40 percent to 100 percent, from 50 percent to 100 percent, from 60 percent to 100 percent, from 70 percent to 100 percent, from 80 percent to 100 percent, from 90 percent to 100 percent or even from 95 percent to 100 percent carbon fiber by weight. In some embodiments, the porous electrode material and/or the electrically conductive material includes from 50 percent to 100 percent, from 60 percent to 100 percent, from 70 percent to 100 percent, from 80 percent to 100 percent, from 90 percent to 100 percent, from 95 percent to 100 percent or even from 97 percent to 100 percent electrically conductive particulate by weight.

The electrically conductive particulate of the porous electrode material and/or the electrically conductive material may include at least one of a metal particulate, electrically conductive carbon particulate and electrically conductive polymer particulate. The metal of the metal particulate may include, but is not limited to, at least one of silver, copper, gold, aluminum, magnesium, molybdenum, iridium, tungsten, zinc, lead, cobalt, nickel, manganese, ruthenium, lithium, iron, tin, platinum, palladium, tantalum, chromium, antimony, vanadium, titanium, zirconium, bismuth, indium, gallium, and cerium.

Combinations of metal may be used, e.g. metal alloys. Noble metals may be particularly useful, due to their stability. The electrically conductive carbon particulate may include, but is not limited to, at least one of carbon particles, carbon flakes, carbon fibers, carbon dendrites, carbon nanotubes and branched carbon nanotubes; combinations may be used. In some embodiments, the electrically conductive carbon particulate may include at least one of graphite particles, graphite flakes, graphite fibers and graphite dendrites; combinations may be used. In some embodiments, the porous electrode material and/or the electrically conductive material includes from 5 percent to 100 percent, from 10 percent to 100 percent, from 20 percent to 100 percent, from 35 percent to 100 percent or even from 50 percent to 100 percent, by weight, of at least one of graphite particles, graphite flakes, graphite fibers and graphite dendrites. The electrically conductive polymer particulate includes, but is not limited to, at least one of polyaniline, polypyrrole and polyacetylene. Combinations of electrically conductive polymer particulate may be used. In some embodiments, the amount of electrically conductive polymer particulate in the porous electrode material and/or the electrically conductive material may be from 5 to 99 percent, from 5 to 95 percent, from 5 to 90 percent, from 5 to 80 percent, from 5 to 70 percent, from 10 to 99 percent, from 10 to 95 percent, from 10 to 90 percent, from 10 to 80 percent, from 10 to 70 percent, from 25 to 99 percent, from 25 to 95 percent, from 25 to 90 percent, from 25 to 80 percent, or even from 5 to 70 percent by weight.

In some embodiments, the porous electrode material and/or the electrically conductive material include an electrically conductive polymer composite comprising at least one polymer and at least one electrically conductive particulate, the at least one electrically conductive particulate may include electrically conductive particulate as described above. The polymer may include at least one of a thermoplastic polymer and a thermoset polymer. The polymer of the porous electrode material and/or the electrically conductive material may be at least one of a polymer particulate and polymer binder resin. In some embodiments of the present disclosure, the polymeric particulate may be at least one of polymer particles, polymer flakes, polymer fibers and polymer dendrites. In some embodiments, the polymer is fused polymer particulate. Fused polymer particulate may be formed from polymer particulates that are brought to a temperature to allow the contact surfaces of adjacent polymer particulates to fuse together. After fusing the individual particulates that formed the fused polymer particulate can still be identified. A fused polymer particulate is porous.

Fused polymer particulate is not particulate that has been completely melted to form a solid substrate, i.e. a non-porous substrate. In some embodiments, the polymer particulate may be fused at a temperature that is not less than 30 degrees centigrade, not less than 20 degrees centigrade or even not less than 10 degrees centigrade lower than the lowest glass lowest transition temperature of the polymer particulate. The polymer particulate may have more than one glass transition temperatures, if, for example, it is a block copolymer or a core-shell polymer. In some embodiments, the polymer particulate may be fused at a temperature that is below the highest melting temperature of the polymer particulate or, when the polymer particulate is an amorphous polymer, no greater than 50 degrees centigrade, no greater than 30 degrees centigrade or even no greater than 10 degrees centigrade above the highest glass transition temperature of the polymer particulate.

In some embodiments of the present disclosure, the polymer of the porous electrode material and/or the electrically conductive material may include a polymer binder resin and the polymer binder resin may be derived from a polymer precursor liquid. A polymer precursor liquid may be at least one of a polymer solution and a reactive polymer precursor liquid, each capable of being at least one of polymerized, cured, dried and fused to form a polymer binder resin. A polymer solution may include at least one polymer dissolved in at least one solvent. A polymer solution may be capable of being at least one of polymerized, cured, dried and fused to form a polymer binder resin. In some embodiments, the polymer solution is dried to form a polymer binder resin. A reactive polymer precursor liquid includes at least one of liquid monomer and liquid oligomer. The monomer may be a single monomer or may be a mixture of at least two different monomers. The oligomer may be a single oligomer or a mixture at least two different oligomers. Mixtures of one or more monomers and one or more oligomers may also be used. The reactive polymer precursor liquid may include at least one, optional, solvent. The reactive polymer precursor liquid may include at least one, optional, polymer, which is soluble in the liquid components of the reactive polymer precursor liquid. The reactive polymer precursor liquid may be capable of being at least one of polymerized, cured, dried and fused to form a polymer binder resin. In some embodiments, the reactive polymer precursor liquid is cured to form a polymer binder resin. In some embodiments, the reactive polymer precursor liquid is polymerized to form a polymer binder resin. In some embodiments, the reactive polymer precursor liquid is cured and polymerized to form a polymer binder resin. The terms "cure", "curing", "cured" and the like are used herein to refer to a reactive polymer precursor liquid that is increasing its molecular weight through one or more reactions that include at least one crosslinking reaction. Generally, curing leads to a thermoset material that may be insoluble in solvents. The terms "polymerize", "polymerizing", "polymerized and the like, generally refer to a reactive polymer precursor liquid that is increasing its molecular weight through one or more reactions that do not include a crosslinking reaction. Generally, polymerization leads to a thermoplastic material that may be soluble in an appropriate solvent. A reactive polymer precursor liquid that is reacting by at least one crosslinking reaction and at least one polymerization reaction may form either a thermoset or thermoplastic material, depending on the degree of polymerization achieved and the amounted crosslinking of the final polymer. Monomers and/or oligomers useful in the preparation of a reactive polymer precursor liquid include, but are not limited to, monomers and oligomers conventionally used to form the polymers, e.g. thermosets, thermoplastics and thermoplastic elastomers, described herein (below). Polymers useful in the preparation of a polymer solution include, but are not limited to the thermoplastic and thermoplastic elastomer polymers described herein (below). In the some embodiments of the present disclosure, the electrically conductive particulate, e.g. electrically conductive carbon particulate, may be adhered to the polymer, polymer particulate and/or polymer binder resin. In some embodiments of the present disclosure, the electrically conductive particulate, e.g. electrically conductive carbon particulate, may be adhered to the surface of the polymer particulate. In some embodiments of the present disclosure, the electrically conductive particulate may be adhered to the surface of the fused polymer particulate.

The polymer of the porous electrode material and/or the electrically conductive material may be selected to facilitate the transfer of select ion(s) of the electrolytes through at least one of the porous electrode material and the electrically conductive material. This may be achieved by allowing the electrolyte to easily wet a given polymer. The material properties, particularly the surface wetting characteristics of the polymer may be selected based on the type of anolyte and catholyte solution, i.e. whether they are aqueous based or non-aqueous based. As disclosed herein, an aqueous based solution is defined as a solution wherein the solvent includes at least 50% water by weight. A non-aqueous base solution is defined as a solution wherein the solvent contains less than 50% water by weight. In some embodiments, the polymer of the porous electrode material and/or the electrically conductive material may be hydrophilic. This may be particularly beneficial when the porous electrode material and/or the electrically conductive material is to be used in conjunction with aqueous anolyte and/or catholyte solutions. In some embodiments the polymer may have a surface contact angle with water, catholyte and/or anolyte of less than 90 degrees. In some embodiments, the polymer may have a surface contact with water, catholyte and/or anolyte of between 85 degrees and 0 degrees, between 70 degrees and 0 degrees, between 50 degrees and 0 degrees, between 30 degrees and 0 degrees, between 20 degrees and 0 degrees, or even between 10 degrees and 0 degrees.

Polymer (polymer type) of the porous electrode material and/or the electrically conductive material, which may be a polymer particulate or a polymer binder resin, may include thermoplastic resins (including thermoplastic elastomer), thermoset resins (including glassy and rubbery materials) and combinations thereof. Useful thermoplastic resins include, but are not limited to, homopolymer, copolymer and blends of at least one of polyalkylene, e.g. polyethylene, high molecular weight polyethylene, high density polyethylene, ultra-high molecular weight polyethylene, polypropylene, high molecular weight polypropylene;

polyacrylate; polymethacrylate, styrene and styrene based random and block copolymer, e.g. styrene-butadiene-styrene; polyester, e.g. polyethylene terephtahalate; polycarbonate, polyamide, polyamide-amine; polyalkylene glycol, e.g. polyethylene glycol and polypropylene glycol; polyurethane; polyether; chlorinated polymer, e.g. polyvinyl chloride; fluoropolymers including perfluorinated fluoropolymers, e.g. polytetrafluoroethylene (PTFE) and partially fluorinated fluoropolymer, e.g. . polyvinylidene fluoride, each of which may be semi-crystalline and/or amorphous; polyimide, polyetherimide, polysulphone; polyphenylene oxide; and polyketone. Useful thermoset resins include, but are not limited to, homopolymer, copolymer and/or blends of at least one of epoxy resin, phenolic resin, polyurethanes, urea- formadehyde resin and melamine resin.

In some embodiments, the polymer of the porous electrode material and/or the electrically conductive material has a softening temperature, e.g. the glass transition temperature and/or the melting temperature of between 20 degrees centigrade and 400 degrees centigrade, between 20 degrees centigrade and 300 degrees centigrade, between 20 degrees centigrade and 200 degrees centigrade, between 35 degrees centigrade and 400 degrees centigrade, between 35 degrees centigrade and 300 degrees centigrade, between 35 degrees centigrade and 200 degrees centigrade, between 50 degrees centigrade and 400 degrees centigrade, between 50 degrees centigrade and 300 degrees centigrade, between 50 degrees centigrade and 200 degrees centigrade, between 75 degrees centigrade and 400 degrees centigrade, between 75 degrees centigrade and 300 degrees centigrade, or even between 75 degrees centigrade and 200 degrees centigrade.

In some embodiments, the polymer particulate is composed of two or more polymers and has a core-shell structure, i.e. an inner core comprising a first polymer and an outer shell comprising a second polymer. In some embodiments, the polymer of the outer shell, e.g. second polymer, has a softening temperature, e.g. the glass transition temperature and/or the melting temperature that is lower than softening temperature of the first polymer. In some embodiments, the second polymer has a softening temperature, e.g. the glass transition temperature and/or the melting temperature of between 20 degrees centigrade and 400 degrees centigrade, between 20 degrees centigrade and 300 degrees centigrade, between 20 degrees centigrade and 200 degrees centigrade, between 35 degrees centigrade and 400 degrees centigrade, between 35 degrees centigrade and 300 degrees centigrade, between 35 degrees centigrade and 200 degrees centigrade, between 50 degrees centigrade and 400 degrees centigrade, between 50 degrees centigrade and 300 degrees centigrade, between 50 degrees centigrade and 200 degrees centigrade, between 75 degrees centigrade and 400 degrees centigrade, between 75 degrees centigrade and 300 degrees centigrade, or even between 75 degrees centigrade and 200 degrees centigrade. The polymer of the porous electrode material and/or the electrically conductive material may be an ionic polymer or non-ionic polymer. Ionic polymer include polymer wherein a fraction of the repeat units are electrically neutral and a fraction of the repeat units have an ionic functional group, i.e. an ionic repeat unit. In some embodiments, the polymer is an ionic polymer, wherein the ionic polymer has a mole fraction of repeat units having an ionic functional group of between 0.005 and 1. In some embodiments, the polymer is a non- ionic polymer, wherein the non-ionic polymer has a mole fraction of repeat units having an ionic functional group of from less than 0.005 to 0. In some embodiments, the polymer is a non-ionic polymer, wherein the non-ionic polymer has no repeat units having an ionic functional group. In some embodiments, the polymer consists essentially of an ionic polymer. In some embodiments, the polymer consists essentially of a non-ionic polymer. Ionic polymer includes, but is not limited to, ion exchange resins, ionomer resins and combinations thereof. Ion exchange resins may be particularly useful.

As broadly defined herein, ionic resin include resin wherein a fraction of the repeat units are electrically neutral and a fraction of the repeat units have an ionic functional group. In some embodiments, the ionic resin has a mole fraction of repeat units with ionic functional groups between 0.005 and 1. In some embodiments, the ionic resin is a cationic resin, i.e. its ionic functional groups are negatively charged and facilitate the transfer of cations, e.g.

protons, optionally, wherein the cationic resin is a proton cationic resin. In some

embodiments, the ionic resin is an anionic exchange resin, i.e. its ionic functional groups are positively charged and facilitate the transfer of anions. The ionic functional group of the ionic resin may include, but is not limited, to carboxylate, sulphonate, sulfonamide, quaternary ammonium, thiuronium, guanidinium, imidazolium and pyridinium groups.

Combinations of ionic functional groups may be used in an ionic resin.

Ionomer resin include resin wherein a fraction of the repeat units are electrically neutral and a fraction of the repeat units have an ionic functional group. As defined herein, an ionomer resin will be considered to be a resin having a mole fraction of repeat units having ionic functional groups of no greater than 0.15. In some embodiments, the ionomer resin has a mole fraction of repeat units having ionic functional groups of between 0.005 and 0.15, between 0.01 and 0.15 or even between 0.3 and 0.15. In some embodiments the ionomer resin is insoluble in at least one of the anolyte and catholyte. The ionic functional group of the ionomer resin may include, but is not limited, to carboxylate, sulphonate, sulfonamide, quaternary ammonium, thiuronium, guanidinium, imidazolium and pyridinium groups. Combinations of ionic functional groups may be used in an ionomer resin. Mixtures of ionomer resins may be used. The ionomers resin may be a cationic resin or an anionic resin. Useful ionomer resin include, but are not limited to NAFION, available from DuPont, Wilmington, Delaware; AQUIVION, a perfluorosulfonic acid, available from SOLVAY, Brussels, Belgium; FLEMION and SELEMION, fluoropolomer ion exchange resin, from Asahi Glass, Tokyo, Japan; FUMASEP ion exchange resin, including FKS, FKB, FKL, FKE cation exchange resins and FAB, FAA, FAP and FAD anionic exchange resins, available from Fumatek, Bietigheim-Bissingen, Germany, polybenzimidazols, and ion exchange materials and membranes described in U.S. Pat. No. 7,348,088, incorporated herein by reference in its entirety.

Ion exchange resin include resin wherein a fraction of the repeat units are electrically neutral and a fraction of the repeat units have an ionic functional group. As defined herein, an ion exchange resin will be considered to be a resin having a mole fraction of repeat units having ionic functional groups of greater than 0.15 and less than 1.00. In some embodiments, the ion exchange resin has a mole fraction of repeat units having ionic functional groups of greater than 0.15 and less than 0.90, greater than 0.15 and less than 0.80, greater than 0.15 and less than 0.70, greater than 0.30 and less than 0.90, greater than 0.30 and less than 0.80, greater than 0.30 and less than 0.70 greater than 0.45 and less than 0.90, greater than 0.45 and less than 0.80, and even greater than 0.45 and less than 0.70. The ion exchange resin may be a cationic exchange resin or may be an anionic exchange resin. The ion exchange resin may, optionally, be a proton ion exchange resin. The type of ion exchange resin may be selected based on the type of ion that needs to be transported between the anolyte and catholyte through the ion permeable membrane. In some embodiments the ion exchange resin is insoluble in at least one of the anolyte and catholyte. The ionic functional group of the ion exchange resin may include, but is not limited, to carboxylate, sulphonate, sulfonamide, quaternary ammonium, thiuronium, guanidinium, imidazolium and pyridinium groups.

Combinations of ionic functional groups may be used in an ion exchange resin. Mixtures of ion exchange resins resin may be used. Useful ion exchange resins include, but are not limited to, fluorinated ion exchange resins, e.g. perfluorosulfonic acid copolymer and perfluorosulfonimide copolymer, a sulfonated polysulfone, a polymer or copolymer containing quaternary ammonium groups, a polymer or copolymer containing at least one of guanidinium or thiuronium groups a polymer or copolymer containing imidazolium groups, a polymer or copolymer containing pyridinium groups. The polymer may be a mixture of ionomer resin and ion exchange resin. In some embodiments, the amount of polymer contained in the of the porous electrode material and/or the electrically conductive material, on a weight basis, may be from 1 to 95 percent, from 5 to 95 percent, from 10 to 95 percent, from 20 to 95 percent, from 30 to 95 percent, from 1 to 90 percent, from 5 to 90 percent, from 10 to 90 percent, from 20 to 90 percent, from 30 to 90 percent, from 1 to 75 percent, from 5 to 75 percent, from 10 to 75 percent, from 20 to 75 percent, from 30 to 75 percent, from 1 to 70 percent, from 5 to 70 percent, from 10 to 70 percent, from 20 to 70 percent, from 30 to 70 percent, from 1 to 60 percent, from 5 to 60, from 10 to 60 percent, from 20 to 60 percent, from 30 to 60 percent, from 1 to 50 percent, from 5 to 50 percent, from 10 to 50 percent, from 20 to 50 percent, from 30 to 50 percent, from 1 to 40 percent, from 5 to 40 percent, from 10 to 40 percent, from 20 to 40 percent, or even from 30 to 40 percent.

The porous electrode material and/or the electrically conductive material of the present disclosure may include non-electrically conductive, inorganic particulate, e.g. non- electrically conductive inorganic filler. Non-electrically conductive inorganic filler includes, but is not limited to, metal oxide such as silica, alumina, zirconia and the like and

combinations thereof. In some embodiments, the porous electrode material and/or the electrically conductive material includes from 0.5 percent to 20 percent, from 0.5 percent to 15 percent, from 0.5 percent to 10 percent, or even from 0.5 percent to 5 percent by weight non-electrically conductive inorganic filler. Non-electrically conductive inorganic filler may be used to improve various mechanical properties, e.g. tensile strength, toughness and/or flexing or bending strength

The polymer and electrically conductive particulate are fabricated into the porous electrode material and/or the electrically conductive material by mixing the polymer and electrically conductive particulate to form an electrically conductive blend, coating the electrically conductive blend into the at least one flow channel of the flow plate substrate (with respect to the porous electrode material) or coating the electrically conductive blend into the at least one vias (with respect to the electrically conductive material), and providing at least one of a fusing, curing, polymerizing and drying treatment to form porous electrode material and/or an electrically conductive material. The porous electrode material and/or the electrically conductive material may be in the form of a continuous sheet or layer. After drying or during drying, the temperature may be such that the temperature is near, at or above the softening temperature of the polymer, e.g. the glass transition temperature and/or the melting temperature of the polymer, which may aid in the adhering of electrically conductive particulate to the polymer and/or further fuse the polymer. The processing of the polymer and electrically conductive particulate blend may be modified by those of ordinary skill in the art to produce a final material that is porous or non-porous.

The electrically conductive material is contained in at least a portion of the at least one via. In some embodiments, 20 to 100 percent, 30 to 100 percent, 40 to 100 percent, 50 to 100 percent, 60 to 100 percent, 70 to 100 percent, 80 to 100 percent, 90 to 100 percent or even from 95 to 100 percent of the volume of the at least one via contains electrically conductive material. Enhanced electrical performance (e.g. greater electrical conductivity and/or lower electrical resistance) may be obtained when 50 to 100 percent, 60 to 100 percent, 70 to 100 percent, 80 to 100 percent, 90 to 100 percent or even from 95 to 100 percent of the volume of the at least one via contains electrically conductive material. The volume of the at least one via is an inherent property of the at least one via and the volume is based on the dimensions and number of the at least one via.

The porous electrode material is contained in at least a portion of the at least one flow channel of the flow plate substrate. In some embodiments, 20 to 100 percent, 30 to 100 percent, 40 to 100 percent, 50 to 100 percent, 60 to 100 percent, 70 to 100 percent, 80 to 100 percent, 90 to 100 percent or even from 95 to 100 percent of the volume of the at least one flow channel contains porous electrode material. Enhanced electrical performance (e.g. greater electrical conductivity and/or lower electrical resistance) may be obtained when 50 to 100 percent, 60 to 100 percent, 70 to 100 percent, 80 to 100 percent, 90 to 100 percent or even from 95 to 100 percent of the volume of the at least one flow channel contains porous electrode material. The volume of the at least one flow channel is an inherent property of the at least one flow channel and the volume is based on the dimensions and number of the at least one flow channel.

In some embodiments, the electrically conductive material includes at least one of an electrically conductive sheet, an electrically conductive pin and a plurality of electrically conductive pins. The electrically conductive material may be a solid electrically conductive material, i.e. impervious to fluid flow. In some embodiments, the electrically conductive material includes at least one of metal sheet, a metal pin and a plurality of metal pins. In some embodiments, the metal of the at least one of metal sheet, a metal pin and a plurality of metal pins may include at least one of silver, copper, gold, aluminum, magnesium, molybdenum, iridium, tungsten, zinc, lead, cobalt, nickel, manganese, ruthenium, lithium, iron, tin, platinum, palladium, tantalum, chromium, antimony, vanadium, titanium, zirconium, bismuth, indium, gallium, and cerium. Noble metals may be particularly useful, due to their stability. In some embodiments, the electrically conductive material includes from 70 to 100 percent, from 80 to 100, from 90 to 100 percent, from 95 to 100 percent, from 98 to 100 percent or even from 99 to 100 percent by weight metal. In some embodiments, the electrically conductive material is 100 percent metal by weight. In some embodiments, the electrically conductive material contains less than 20 percent, less than 10 percent, less than 5 percent, less than 1 percent or even 0 percent voids, based on volume.

In one embodiment, polymer particulate and electrically conductive particulate may be mixed together as dry components, forming a dry blend. Milling media, e.g. milling beads may, be added to the dry blend to facilitate the mixing process and/or to at least partially embed the electrically conductive particulate into the surface of the polymer particulate. The dry blend may then be coated, using conventional techniques, including but not limited to knife coating and electrostatic coating, on the flow plate substrate. The coating, which fills at least one of the at least one flow channel and the at least one via, may then be heat treated at temperatures near, at or above the softening temperature of the polymer particulate, e.g. the glass transition temperature and/or the melting temperature of the polymer particulate, to fuse at least a portion of the polymer parti culate/carbon particulate dry blend into a porous material, thereby forming a porous electrode material and/or the electrically conductive material. Excess coating may be removed by conventional techniques. In some

embodiments, the excess coating is removed prior to heat treatment. The porous electrode material and/or the electrically conductive material may be in the form of a sheet. The thermal treatment may also aid in adhering the electrically conductive carbon particulate to the surface of the polymer particulate. The thermal treatment may be conducted under pressure, e.g. in a heated press or between heated rolls. The press and or heated rolls may be set to provide a specific desired gap, which will facilitate obtaining a desired thickness.

In an alternative embodiment, the dry blend or the individual particulates may be added to an appropriate liquid medium, i.e. a solvent, and mixed, using conventional techniques, e.g. blade mixing or other agitation, forming a polymer particulate/electrically conductive particulate dispersion. Milling media, e.g. milling beads, may be added to the dispersion to facilitate the mixing process and/or to at least partially embed the electrically conductive particulate into the surface of the polymer particulate. If milling media is employed, agitation is usually achieved by shaking or rolling the container holding the dry blend. The dispersion may be coated on the flow plate substrate using conventional techniques, e.g. knife coating, which fills at least one of the at least one flow channel and the at least one via with dispersion. The coating may then be dried, via heat treatment at elevated temperatures, to remove the liquid medium and to fuse at least a portion of the polymer particulate/electrically conductive particulate blend into a porous material, thereby forming a porous electrode material and/or the electrically conductive material. Excess coating may be removed by conventional techniques. In some embodiments, the excess coating is removed prior to heat treatment. The porous electrode material and/or the electrically conductive material may be in the form of a sheet. The thermal treatment may also aid in adhering the electrically conductive particulate to the surface of the polymer particulate. The heat treatment used to dry the dispersion, i.e. evaporate the liquid medium, and to fuse at least a portion of the polymer particulate may be at the same or different temperatures. Vacuum may be used to remove the liquid medium or aid in the removal of the liquid medium. In another embodiment, the polymer particulate may be obtained as a dispersion, e.g. the dispersion resulting from a suspension or emulsion polymerization, and the electrically conductive carbon particulate may be added to this dispersion. Mixing, coating, drying and fusing may be conducted as described above.

In yet another alternative embodiment, the dry blend or the individual particulates may be added to an appropriate liquid medium, i.e. polymer precursor liquid, and mixed, using conventional techniques, e.g. blade mixing or other agitation, forming a polymer particulate/electrically conductive particulate dispersion. Milling media, e.g. milling beads, may be added to the dispersion to facilitate the mixing process and/or to at least partially embed the electrically conductive particulate into the surface of the polymer particulate. If milling media is employed, agitation is usually achieved by shaking or rolling the container holding the dispersion. The dispersion may be coated on the flow plate substrate using conventional techniques, e.g. knife coating, which fills at least one of the at least one flow channel and at least one via with dispersion. The coating may then be at least one of dried, cured, polymerized and fused, forming a binder resin and transforming the polymer particulate/electrically conductive particulate blend into a porous material or non-porous material, thereby forming a porous electrode material and/or the electrically conductive material. Excess coating may be removed by conventional techniques. In some

embodiments, the excess coating is removed prior to the at least one of drying, curing, polymerizing and fusing. The porous electrode material and/or the electrically conductive material may be in the form of a sheet. If thermal treatment is used to form the polymer binder resin or a secondary thermal treatment is applied to the polymer binder resin, the temperature may be such that the temperature is near, at or above the softening temperature of the polymer binder resin, e.g. the glass transition temperature and/or the melting temperature of the polymer binder resin, which may aid in the adhering of electrically conductive particulate to the binder resin and/or further fuse the binder resin.

In another embodiment, an electrically conductive particulate may be dispersed in a polymer precursor liquid and mixed using conventional techniques, e.g. blade mixing or other agitation,. Milling media, e.g. milling beads, may be added to the dispersion to facilitate the mixing process. If milling media is employed, agitation is usually achieved by shaking or rolling the container holding the dispersion. The resulting dispersion may be coated on a flow plate substrate, using conventional techniques, e.g. knife coating, which fills the at least one via with dispersion. The polymer precursor liquid coating may then be at least one of dried, cured, polymerized and fused, forming an electrically conductive polymer composite suitable as an electrically conductive material, e.g. a non-porous electrically conductive material. Excess coating may be removed by conventional techniques. In some

embodiments, the excess coating is removed prior to the at least one of drying, curing, polymerizing and fusing. The electrically conductive material may be in the form of a sheet. If a thermal treatment is used to form the polymer binder resin or a secondary thermal treatment is applied to the polymer binder resin, the temperature may be such that the temperature is near, at or above the softening temperature of the polymer binder resin, e.g. the glass transition temperature and/or the melting temperature of the polymer binder resin, which may aid in the adhering of electrically conductive particulate to the binder resin and/or further fuse the binder resin.

In some embodiments, the polymer precursor liquid is a polymer solution, e.g. at least one polymer dissolved in at least one solvent, and the electrically, conductive particulate is dispersed in the polymer solution. Milling media, e.g. milling beads, may be added to the dispersion to facilitate the mixing process. The resulting dispersion may be coated on a flow plate substrate using conventional techniques, e.g. knife coating, which fills at least one of the at least one flow channel and the at least one via with dispersion. The dispersion coating may be dried, forming a polymer binder resin and a corresponding, porous material, the porous electrode material and/or the electrically conductive material. Excess coating may be removed by conventional techniques. In some embodiments, the excess coating is removed prior to drying. The porous electrode material and/or the electrically conductive material may be in the form of a sheet. After drying or during drying, the temperature may be such that the temperature is near, at or above the softening temperature of the polymer binder resin, e.g. the glass transition temperature and/or the melting temperature of the polymer binder resin, which may aid in the adhering of electrically conductive particulate to the binder resin and/or further fuse the binder resin.

The solvent used in the polymer solution is not particularly limited, except that the polymer that will form the polymer binder resin must be soluble in it. The solvent may be selected based on the chemical structure of the polymer and the solubility of the polymer in the solvent. The optional solvent used in the reactive polymer precursor liquid is not particularly limited, except that the at least one of a liquid monomer and a liquid oligomer is soluble in the solvent. Useful solvents include, but are not limited to, water, alcohols (e.g. methanol, ethanol and propanol), acetone, ethyl acetate, alkyl solvents (e.g. pentane, hexane, cyclohexane, heptane and octane), methyl ethyl ketone, ethyl ethyl ketone, dimethyl ether, petroleum ether, toluene, benzene, xylenes, dimethylformamide, dimethylsulfoxide, chloroform, carbon tetrachloride, chlorobenzene and mixtures thereof.

In some embodiments, the polymer precursor liquid is a reactive polymer precursor liquid, e.g. at least one of a liquid monomer and a liquid oligomer, and the electrically conductive particulate is dispersed in the reactive polymer precursor solution. The reactive polymer precursor may optionally include at least one solvent and may optionally include at least one polymer that is soluble in the liquid components of the reactive polymer precursor liquid. Milling media, e.g. milling beads, may be added to the dispersion to facilitate the mixing process. The resulting dispersion may be coated on a flow plate substrate, using conventional techniques, e.g. knife coating, which fills at least one of the at least one flow channel and the at least one via with dispersion. The reactive polymer precursor liquid coating may then be at least one of dried, cured, polymerized and fused, forming a polymer binder resin and a corresponding porous electrode material and/or the electrically conductive material. Excess coating may be removed by conventional techniques. In some

embodiments, the excess coating is removed prior to drying, curing, polymerizing and fusing. The porous electrode material and/or the electrically conductive material may be in the form of a sheet. If a thermal treatment is used to form the polymer binder resin or a secondary thermal treatment is applied to the polymer binder resin, the temperature may be such that the temperature is near, at or above the softening temperature of the polymer binder resin, e.g. the glass transition temperature and/or the melting temperature of the polymer binder resin, which may aid in the adhering of electrically conductive particulate to the binder resin and/or further fuse the binder resin.

When the polymer precursor liquid is a reactive polymer precursor liquid, the reactive polymer precursor liquid may include appropriate additives to aid in the curing and/or polymerization of the reactive polymer precursor liquid. Additives include, but are not limited to catalysts, initiators, curatives, inhibitors, chain transfer agents and the like. Curing and/or polymerization may be conducted by at least one of thermal and radiation. Radiation may include actinic radiation, including UV and visible radiation. Upon curing, the reactive polymer precursor liquid may form a B-stage polymer binder resin, i.e. capable of a second step cure. If B-stageable polymer binder resins are desired, the first cure may be a thermal cure, and the second cure may be a radiation cure, both curing steps may be thermal cure, for example, at two different cure temperatures, both cures may be radiation cure, at two different wavelengths, or the first cure may be a radiation cure and the second cure a thermal cure.

Electrically Conductive layer

The optional electrically conductive layer can include any electrically conductive species known in the art. The electrically conductive layer may be a single layer or multiple layers. The electrically conductive layer may include at least one of a metal, e.g. metal film, electrically conductive particulate (e.g. electrically conductive carbon particulate), electrically conductive polymer and electrically conductive polymer composite, as previously described. In some embodiments, the electrically conductive layer may include at least one of a metal film, an electrically conductive particulate and an electrically conductive polymer composite comprising polymer and the electrically conductive particulate. Metal film, electrically conductive particulate and electrically conductive polymer composite comprising polymer and electrically conductive particulate have been described with respect to the porous electrode material and electrically conductive material and the same materials may be used for the electrically conductive layer. The metal may include at least one of silver, copper, gold, aluminum, magnesium, molybdenum, iridium, tungsten, zinc, lead, cobalt, nickel, manganese, ruthenium, lithium, iron, tin, platinum, palladium, tantalum, chromium, antimony, vanadium, titanium, zirconium, bismuth, indium, gallium, and cerium. The electrically conductive layer may include an electrically conductive adhesive, e.g. at least one of an electrically conductive pressure sensitive adhesive, an electrically conductive hot melt adhesive and an electrically conductive cure in place adhesive. Electrically conductive adhesives known in the art may be used. In some embodiments, the electrically conductive adhesive includes at least one of a metal, electrically conductive carbon and electrically conductive polymer. The electrically conductive layer may be in the form of a sheet, e.g. a continuous sheet. One example of a suitable sheet for an electrically conductive layer is a 0.6 mm thick sheet available under the trade designation SIGRACELL TF6, from SGL Carbon GmbH, Meitingen, Germany. The electrically conductive layer may be a discontinuous layer, including a plurality of discrete regions or islands of electrically conductive material. The discrete regions may align with the at least one via, e.g. a plurality of vias, of the flow plate substrate. In some embodiments, the electrically conductive layer is impervious to fluid. Generally, an electrically conductive layer, which is impervious to fluid, will be used when the electrically conductive material contained in the at least one via of the flow plate substrate is a porous material that is not impervious to fluid. In these embodiments, the electrically conductive layer, which is impervious to fluid, prevents fluid communication between the first major surface and the second major surface of the flow plate substrate, through the thickness of the flow plate substrate. The electrically conductive layer may be laminated, insert molded or compression molded to or with the flow plate substrate.

Ion Permeable Membrane

In some embodiments, the monopolar plate-electrode assemblies of the present disclosure may include an ion permeable membrane, ion exchange membranes being particularly useful. Ion permeable membranes and ion exchange membranes known in the art may be used. Ion permeable membranes, e.g. ion exchange membranes, are often referred to as separators and may be prepared from ionic polymers. Ionic polymer useful in ion permeable membranes of the present disclosure include, but is not limited to, ion exchange resin and ionomer resin, as previously described and combinations thereof. Ion exchange resins may be particularly useful.

The ionic polymer of the ion permeable membrane may include polymer wherein a wherein a fraction of the repeat units are electrically neutral and a fraction of the repeat units have an ionic functional group. In some embodiments, the ionic polymer has a mole fraction of repeat units with ionic functional groups between 0.005 and 1, between 0.01 and 1, between 0.05 and 1, between 0.005 and 0.7, between 0.01 and 0.7, between 0.05 and 0.7, between 0.005 and 0.4, between 0.01 and 0.4 or even between 0.05 and 0.4. In some embodiments, the ionic polymer is a cationic resin, i.e. its ionic functional groups are negatively charged and facilitate the transfer of cations, e.g. protons, optionally, wherein the cationic resin is a proton cationic resin. In some embodiments, the ionic polymer is an anionic exchange resin, i.e. its ionic functional groups are positively charged and facilitate the transfer of anions. The ionic functional group of the ionic polymer may include, but is not limited, to carboxylate, sulphonate, sulfonamide, quaternary ammonium, thiuronium, guanidinium, imidazolium and pyridinium groups. Combinations of ionic functional groups may be used in an ionic polymer.

Ionic polymer may include conventional thermoplastics and thermosets that have been modified by conventional techniques to include at least one of type of ionic functional group, e.g. anionic and/or cationic. Useful thermoplastic resins that may be modified include, but are not limited to, at least one of polyethylene, e.g. high molecular weight polyethylene, high density polyethylene, ultra-high molecular weight polyethylene, polypropylene, e.g. high molecular weight polypropylene, polystyrene, poly(meth)acrylates, e.g. polyacrylates based on acrylic acid that may have the acid functional group exchanged for, for example, an alkali metal, chlorinated polymer, e.g. polyvinyl chloride, fluoropolymer, e.g. perfluorinated fluoropolymer and partially fluorinated fluoropolymer (for example polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF)) each of which may be semi-crystalline and/or amorphous, polyetherimides and polyketones. Useful thermoset resins include, but are not limited to, at least one of epoxy resin, phenolic resin, polyurethanes, urea-formadehyde resin and melamine resin.

In some embodiments, the ion permeable membranes, e.g. ion exchange membranes, may include a fluorinated ion exchange resin. Ion permeable membranes useful in the embodiments of the present disclosure may be fabricated from ion exchange resins and/or ionomer known in in the art or may be commercially available as membrane films and include, but are not limited to, NAFION PFSA MEMBRANES, available from DuPont, Wilmington, Delaware; AQUIVION PFSA, a perfluorosulfonic acid, available from

SOLVAY, Brussels, Belgium; FLEMION and SELEMION, fluoropolomer ion exchange membranes, available from Asahi Glass, Tokyo, Japan; FUMASEP ion exchange membranes, including FKS, FKB, FKL, FKE cation exchange membranes and FAB, FAA, FAP and FAD anionic exchange membranes, available from Fumatek, Bietigheim-Bissingen, Germany and ion exchange membranes, perfluorosulfonic acid ionomer having an 825 equivalent weight, available under the trade designation "3M825EW", available as a powder or aqueous solution, from the 3M Company, St. Paul, Minnesota, perfluorosulfonic acid ionomer having an 725 equivalent weight, available under the trade designation "3M725EW", available as a powder or aqueous solution, from the 3M Company and materials described in U.S. Pat. No. 7,348,088, incorporated herein by reference in its entirety. In some embodiments, the ion exchange membrane includes a fluoropolymer. In some embodiments, the fluoropolymer of the ion exchange membrane may contain from 10% to 90%, from 20% to 90%, from 30% to 90% or even from 40% to 90% fluorine by weight.

The ion permeable membranes of the present disclosure may be obtained as free standing films from commercial suppliers or may be fabricated by coating a solution of the appropriate membrane resin, e.g. ion exchange membrane resin, in an appropriate solvent, and then heating to remove the solvent. The membrane may be formed from a coating solution by coating the solution on a release liner and then drying the membrane coating solution coating to remove the solvent.

Any suitable method of coating may be used to coat the membrane coating solution on a release liner. Typical methods include both hand and machine methods, including hand brushing, notch bar coating, fluid bearing die coating, wire-wound rod coating, fluid bearing coating, slot-fed knife coating, and three-roll coating. Most typically three-roll coating is used. Coating may be achieved in one pass or in multiple passes. Coating in multiple passes may be useful to increase coating weight without corresponding increases in cracking of the ion permeable membrane.

The amount of solvent, on a weight basis, in the membrane coating solution may be from 5 to 95 percent, from 10 to 95 percent, from 20 to 95 percent, from 30 to 95 percent, from 40 to 95 percent, from 50 to 95 percent, from 60 to 95 percent, from 5 to 90 percent, from 10 to 90 percent, from 20 percent to 90 percent, from 30 to 90 percent, from 40 to 90 percent, from 50 to 90 percent, from 60 to 90 percent, from 5 to 80 percent, from 10 to 80 percent from 20 percent to 80 percent, from 30 to 80 percent, from 40 to 80 percent, from 50 to 80 percent, from 60 to 80 percent, from 5 percent to 70 percent, from 10 percent to 70 percent, from 20 percent to 70 percent, from 30 to 70 percent, from 40 to 70 percent, or even from 50 to 70 percent..

The amount of membrane resin, e.g. ion exchange resin and ionomer resin, on a weight basis, in the membrane coating solution may be from 5 to 95 percent, from 5 to 90 percent, from 5 to 80 percent, from 5 to 70 percent, from 5 to 60 percent, from 5 to 50 percent, from 5 to 40 percent, from 10 to 95 percent, from 10 to 90 percent, from 10 to 80 percent, from 10 to 70 percent, from 10 to 60 percent, from 10 to 50 percent, from 10 to 40 percent, from 20 to 95 percent, from 20 to 90 percent, from 20 to 80 percent, from 20 to 70 percent, from 20 to 60 percent, from 20 to 50 percent, from 20 to 40 percent, from 30 to 95 percent, from 30 to 90 percent, from 30 to 80 percent, from 30 to 70 percent, from 30 to 60 percent, or even from 30 to 50 percent.

The thickness of the ion permeable membrane may be from 5 microns to 250 microns, from 5 microns to 200 microns, from 5 microns to 150 microns, from 5 microns to 100 microns, from 10 microns to 250 microns, from 10 microns to 200 microns, from 10 microns to 150 microns, from 5 microns to 10 microns, from 15 microns to 250 microns, from 15 microns to 200 microns, from 15 microns to 150 microns, or even from 15 microns to 100 microns. Discontinuous Transport Protection Layer

In some embodiments, the monopolar plate-electrode assemblies of the present disclosure may include a discontinuous transport protection layer. The discontinuous transport protection layer protects the ion permeable membrane from puncture by the electrically conductive particulate, e.g. carbon fibers, of the porous electrode material and thus may prevents localized shorting that has been found to be an issue in some electrochemical cell and liquid flow battery designs. The discontinuous transport protection layers of the present disclosure may also improve fluid flow within the monopolar plate-electrode assembly and subsequently fluid flow within an electrochemical cell and/or battery. The term "transport" within the phrase "transport protection layer" refers to fluid transport within and/or through the protection layer. The term "discontinuous" refers to the porous nature of the transport protection layer, which allows fluid communication through at least its thickness, i.e. between the first major surface and the opposed second major surface of the discontinuous transport protection layer. This may lead to improved, i.e. decreased, or at least not significantly altered cell resistance, contrary to what one might expect to occur with the inclusion of an additional layer within the monopolar plate-electrode assembly and subsequently with the inclusion of an additional layer in an electrochemical cell and/or battery. The discontinuous transport protection layer is generally a porous layer, e.g. a nonwoven or woven fabric or mesh material, providing a space between the porous electrode material and the ion permeable membrane.

The thickness of the discontinuous transport protection layer may be from 25 microns to 3000 microns, from 25 microns to 2000 microns, from 25 microns to 1000 microns, from 25 microns to 500 microns, from 50 microns to 3000 microns, from 50 microns to 2000 microns, from 50 microns to 1000 microns, from 50 microns to 500 microns, from 75 microns to 3000 microns, from 75 microns to 2000 microns, from 75 microns to 1000 microns, from 75 microns to 500 microns, from 100 microns to 3000 microns, from 100 microns to 2000 microns, from 100 microns to 1000 microns, or even from 100 microns to 500 microns.

The monopolar plate-electrode assemblies of the present disclosure may be used to fabricate an electrochemical cell for use in, for example, a liquid flow battery, e.g. a redox flow battery. Generally, an electrochemical cell for a liquid flow battery includes two half cells, each half cell including an electrode (e.g. anode or cathode). In some embodiments, the present disclosure provides an electrochemical cell that include at least one monopolar plate- electrode assembly. In one embodiment, the present disclosure provides an electrochemical cell including a monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the present disclosure. In another embodiment, the present disclosure provides an electrochemical cell including two monopolar plate-electrode assemblies, i.e. a first and a second monopolar plate-electrode assembly, according to the present disclosure. In some embodiments, the present disclosure provides an electrochemical cell including a first and a second monopolar plate-electrode assembly according to the present disclosure, wherein the monopolar plate-electrode assemblies are the same construction. When at least two monopolar plate-electrode assemblies are used, the monopolar plate-electrode assemblies may be the same, for examples, both being monopolar plate assembly 100 or, both being monopolar plate-electrode assembly 101; or may be different, e.g. one being monopolar plate-electrode assembly 100 and one being monopolar plate assembly 101. In some embodiments, the present disclosure provides an

electrochemical cell for a liquid flow battery comprising two half cells, each half cell including an electrode, wherein at least one of the half cells includes a monopolar plate- electrode assembly according to any one of the monopolar plate-electrode assemblies of the present disclosure. In some of these embodiments, the electrode of the at least one half cell, which includes the monopolar plate-electrode assembly according to any one of the of the monopolar plate-electrode assemblies of the present disclosure, consists essentially of the porous electrode material of the monopolar plate-electrode assembly. In some embodiments, the present disclosure provides an electrochemical cell for a liquid flow battery comprising two half cells, each half cell including an electrode and each half cell includes a monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the present disclosure. In some of these embodiments, the electrodes of each half cell, wherein each half cell includes a monopolar plate-electrode assembly according to any one of the of the monopolar plate-electrode assemblies of the present disclosure, consist essentially of the porous electrode material of each monopolar plate-electrode assembly. The porous electrode material for each monopolar plate-electrode assembly may be the same or different (two different porous electrode materials).

FIG. 5 A shows schematic cross-sectional side views of an exemplary electrochemical cell according to one exemplary embodiment of the present disclosure. Electrochemical cell 500 includes a single monopolar plate-electrode assembly 100 (without optional electrically conductive layer 70), as previously described in FIGS. 2A-2D. Electrochemical cell 500 further includes ion permeable membrane 80, having a first and second major surface, conventional electrode 55, e.g. carbon fiber mat, and conventional flow plate 105 which includes at least one channel 25. One major surface of ion permeable membrane 80 is adjacent the at least one flow channel 20 of monopolar plate-electrode assembly 100 and the other major surface of ion permeable membrane 80 is adjacent conventional electrode 55. Conventional electrode 55 is disposed between ion permeable membrane 80 and conventional flow plate 105, with the at least one channel 25 of conventional flow plate 105 adjacent conventional electrode 55. The inlet and outlet ports of the monopolar plate-electrode assembly and the conventional flow plate, which would not be visible in this perspective, are indicated by the dashed lines. Electrochemical cell 500 may also include current collectors 201 and 202. Monopolar plate-electrode assembly 100 is in electrical communication with current collector 201 at least through porous electrode material 50 and electrically conductive material 60. Conventional flow plate 105 is electrically conductive and is in electrical communication with conventional electrode 55 and current collector 202 through its major surfaces. Support plates, not shown, may be placed adjacent to the exterior surfaces of current collectors 201 and 202. The support plates are electrically isolated from the current collector and provide mechanical strength and support to facilitate compression of the cell assembly. In some embodiments, electrochemical cell 500 includes at least one monopolar plate-electrode assembly, e.g. monopolar plate-electrode assembly 100, including a flow plate substrate, e.g. flow plate substrate 10 as previously described, a porous electrode material, e.g. porous electrode material 50, as previously described, and an electrically conductive material 60, as previously described. The monopolar plate-electrode assembly of

electrochemical cell 500 may be any of the monopolar plate-electrode assemblies of the present disclosure, for example, monopolar plate-electrode assemblies 100, 101, 101-1, 101-2 and 101-3 (FIGS. 2 A through 2D, FIGS. 4 A through 4D and FIGS 4C-1, 4C-2 and 4C-3, respectively). Electrochemical cell 500 may be divided into two half cells, one which includes monopolar plate-electrode assembly 100 and one that includes conventional flow plate 105 and conventional electrode 55. The electrode of the half cell that includes monopolar plate-electrode assembly 100 includes porous electrode material 50. The electrode of the half cell that includes conventional flow plate 105 includes conventional electrode 55. Note, if the monopolar plate-electrode assembly includes an ion permeable membrane, the ion permeable membrane shown in FIG. 5 A may not be required.

FIG. 5B shows schematic cross-sectional side views of an exemplary electrochemical cell according to one exemplary embodiment of the present disclosure. Electrochemical cell 501 includes two monopolar plate-electrode assemblies 100 and 101 (both without optional electrically conductive layer 70), as previously described in FIGS. 2A through 2D and FIGS. 4A through 4D, respectively. Electrochemical cell 501 further includes ion permeable membrane 80, having a first and second major surface. One major surface of ion permeable membrane 80 is adjacent the at least one flow channel 20 of monopolar plate-electrode assembly 100 and the other major surface of ion permeable membrane 80 is adjacent the at least one flow channel 20 of monopolar plate-electrode assembly 101. Ion permeable membrane 80 is disposed between monopolar plate-electrode assemblies 100 and 101. The inlet and outlet ports of the monopolar plate-electrode assemblies, which would not be visible in this perspective, are indicated by the as dashed lines. Electrochemical cell 501 also may include current collectors 201 and 202. Monopolar plate-electrode assembly 100 is in electrical communication with current collector 201 at least through porous electrode material 50 and electrically conductive material 60 of monopolar plate-electrode assembly 100.

Monopolar plate-electrode assembly 101 is in electrical communication with current collector 202 at least through porous electrode material 50 and electrically conductive material 60 of monopolar plate-electrode assembly 101. Support plates, not shown, may be placed adjacent to the exterior surfaces of current collectors 201 and 202. The support plates are electrically isolated from the current collector and provide mechanical strength and support to facilitate compression of the cell assembly. In some embodiments, electrochemical cell 501 includes at least two monopolar plate-electrode assemblies, e.g. monopolar plate electrode assemblies 100 and 101, each including a flow plate substrate, e.g. flow plate substrate 10 or 11, as previously described, a porous electrode material, e.g. porous electrode material 50 as previously described, and an electrically conductive material 60 as previously described. The monopolar plate-electrode assembly of electrochemical cell 501 may be any of the monopolar plate-electrode assemblies of the present disclosure, for example, monopolar plate-electrode assemblies 100, 101, 101-1, 101-2 and 101-3 (FIGS. 2 A through 2D, FIGS. 4 A through 4D and FIGS. 4C-1, 4C-2 and 4C-3, respectively). Electrochemical cell 501 may be divided into two half cells, one which includes monopolar plate-electrode assembly 100 on the left side of the membrane and one that includes monopolar plate-electrode assembly 101 on the right side of the membrane. The electrode of each half cell that includes monopolar plate- electrode assembly 100 and monopolar plate-electrode assembly 101, respectively, includes porous electrode material 50. The porous electrode material for each monopolar plate- electrode assembly may be the same or different (two different porous electrode materials). Note, if at least one of the monopolar plate-electrode assembly includes an ion permeable membrane, the ion permeable membrane shown in FIG. 5B may not be required. When at least two monopolar plate-electrode assemblies are used, the monopolar plate-electrode assemblies may be the same, e.g. both being a monopolar plate assembly 100 or both being a monopolar plate-electrode assembly 101; or may be different, e.g. one being monopolar plate-electrode assembly 100 and one being monopolar plate assembly 101.

Individual monopolar plate-electrode assemblies may be arranged to form an electrochemical cell stack. The electrochemical cell stacks of the present disclosure may include a plurality of monopolar plate-electrode assemblies, as previously described herein. In one embodiment, the present disclosure provides an electrochemical cell stack including at least two, at least three, at least four, at least five or even at least six monopolar plate- electrode assemblies, according to any one of the monopolar plate-electrode assemblies of the present disclosure. In some embodiments, the monopolar plate-electrode assemblies of the electrochemical cell stack may all have the same construction. In some embodiments, one or more of monopolar plate-electrode assemblies of the electrochemical cell stack may differ from a first monopolar plate-electrode assembly of the electrochemical cell stack. FIG. 6 shows a schematic cross-sectional side view of an exemplary electrochemical cell stack according to one exemplary embodiment of the present disclosure. Electrochemical cell stack 600 includes monopolar plate-electrode assemblies 100a, 100b, 100c (as described as element 100 of FIGS. 2A through 2D) and monopolar plate-electrode assemblies 101a, 101b, 101c (as described as element 101 of FIGS, 4A through 4D). Arranged in this manner, the monopolar plate-electrode assemblies allow anolyte to flow through one set of flow channels, the at least one flow channel of monopolar plate-electrode assemblies 100a, 101b and 100b, and catholyte to flow through a seconds set of flow channels, the at least one flow channel of monopolar plate-electrode assemblies 101a, 101c and 100c, for example. Cell stack 600 includes multiple electrochemical cells, each cell represented by an ion permeable membrane, 80, and the corresponding adjacent monopolar plate-electrode assemblies. Electrochemical cell stack 600 also may include current collectors 201 and 202. The monopolar plate electrode assemblies may be any of the monopolar plate-electrode assemblies of the present disclosure, for example, monopolar plate-electrode assemblies 100, 101, 101-1, 101-2 and 101-3 (FIGS. 2 A through 2D, FIGS. 4 A through 4D and FIGS 4C-1, 4C-2 and 4C-3, respectively). If one or more of the monopolar plate-electrode assemblies of an individual cell include an integral ion permeable membrane (see FIG. 4C-1, for example), the corresponding, separate ion permeable membrane 80 shown in FIG. 6 may not be required. Within an electrochemical cell stack, the monopolar plate-electrode assemblies may be the same or may be different. In some embodiments, at least one of the monopolar plate- electrode assemblies may include optional electrically conductive layer, e.g. electrically conductive layer 70 of FIGS. 2A through 2D and FIGS. 4A through 4D. In some

embodiments, electrically conductive layer 70 may be an electrically conductive adhesive layer, the electrically conductive adhesive layer bonding a first monopolar plate-electrode assembly to a second monopolar plate-electrode assembly. For example, monopolar plate- electrode assembly 101a, which may include optional electrically conductive layer 70 (not shown) adjacent its second major surface, may be bonded to monopolar plate-electrode assembly 101b, through the optional electrically conductive layer disposed between monopolar plate-electrode assembly 101a and monopolar plate-electrode assembly 101b, when the optional electrically conductive layer is an electrically conductive adhesive layer. Support plates, not shown, may be placed adjacent to the exterior surfaces of current collectors 201 and 202. The support plates are electrically isolated from the current collector and provide mechanical strength and support to facilitate compression of the cell assembly. The anolyte and catholyte inlet and outlet ports and corresponding fluid distribution system are not shown. These features may be provided as known in the art.

The monopolar plate-electrode assemblies and their corresponding electrochemical cells and cell stacks of the present disclosure may be used to fabricate liquid flow batteries, e.g. a redox flow battery. In some embodiments, the present disclosure provides a liquid flow battery that includes at least one monopolar plate-electrode assembly according to the present disclosure. In some embodiments, the present disclosure provides a liquid flow battery that includes at least two, at least three, at least four, at least six, at least ten, at least twenty or even more monopolar plate-electrode assemblies according to the present disclosure. In some embodiments, the monopolar plate-electrode assemblies of the liquid flow battery may all have the same construction. In some embodiments, one or more monopolar plate- electrode assemblies of the liquid flow battery may differ from a first monopolar plate- electrode assembly of the liquid flow battery. In one embodiment, the present disclosure provides a liquid flow battery including a monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the present disclosure, for example monopolar plate-electrode assemblies 100, 101, 101-1, 101-2 and 101-3. In some embodiments, the present disclosure provides a liquid flow battery comprising at least one electrochemical cell, said electrochemical cell comprising two half cells, each half cell including an electrode, wherein at least one of the half cells includes a monopolar plate- electrode assembly according to any one of the embodiments of the present disclosure. In some embodiments of this liquid flow battery, the electrode of the at least one half cell, which includes the monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the present disclosure, consists essentially of the porous electrode material of the monopolar plate-electrode assembly. In some embodiments, the present disclosure provides a liquid flow battery comprising at least one electrochemical cell, said electrochemical cell comprising two half cells, each half cell including an electrode, wherein each half cell includes a monopolar plate-electrode assembly according to any one of the embodiments of the present disclosure. In some embodiments of this liquid flow battery, the electrodes of each half cell, wherein each half cell includes a monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the present disclosure, consist essentially of the porous electrode material of the corresponding monopolar plate-electrode assembly. The porous electrode material for each monopolar plate-electrode assembly may be the same or different (two different porous electrode materials).

FIG. 7 shows a schematic view of an exemplary single cell, liquid flow battery according to one exemplary embodiment of the present disclosure. Liquid flow battery 700 includes monopolar plate-electrode assemblies 100 and ion permeable membrane 80, all as previously described. The monopolar plate-electrode assemblies may be any of the monopolar plate-electrode assemblies of the present disclosure, for example, monopolar plate-electrode assemblies 100, 101, 101-1, 101-2 and 101-3 (FIGS. 2A through 2D, FIGS. 4A through 4D and FIGS 4C-1, 4C-2 and 4C-3, respectively). If at least one of the monopolar plate-electrode assemblies include an ion permeable membrane, the ion permeable membrane shown in FIG. 7 may not be required. Liquid flow battery 700 may also include current collectors 201 and 202, anolyte reservoir 220 and anolyte fluid distribution 220', and catholyte reservoir 222 and catholyte fluid distribution system 222' . Pumps for the fluid distribution system are not shown. Current collectors 201 and 202 may be connected to an external circuit which includes an electrical load (not shown). Support plates, not shown, may be placed adjacent to the exterior surfaces of current collectors 201 and 202. The support plates are electrically isolated from the current collector and provide mechanical strength and support to facilitate compression of the cell assembly. Although a single cell liquid flow battery is shown, it is known in the art that liquid flow batteries may contain multiple electrochemical cells, i.e. a cell stack. For example, cell stack 600 may replace the single electrochemical cell of FIG. 7. Flow fields may be present, but this is not a

requirement. In some embodiments, multiple cell stacks may be used to form a liquid flow battery. The multiple cell stacks may be connected in series.

The monopolar plate-electrode assemblies of the present disclosure may provide improved cell short resistance and cell resistance. Cell short resistance is a measure of the resistance an electrochemical cell has to shorting, for example, due to puncture of the membrane by conductive fibers of the electrode. In some embodiments, a test cell, as described in the Example section of the present disclosure, which includes at least one of a an electrode assembly and membrane-electrode assembly of the present disclosure may have a cell short resistance of greater than 1000 ohm-cm², greater than 5000 ohm-cm² or even greater than 10000 ohm-cm². In some embodiments the cell short resistance may be less than 10000000 ohm-cm². Cell resistance is a measure of the electrical resistance of an

electrochemical cell through the membrane, i.e. laterally across the cell, shown in FIG. 5 or FIG. 7. In some embodiments, a test cell, as described in the Example section of the present disclosure, which includes at least one monopolar plate-electrode assembly of the present disclosure may have a cell resistance of between 0.01 and 10 ohm-cm², 0.01 and 5 ohm-cm², between 0.01 and 3 ohm-cm², between 0.01 and 1 ohm-cm², between 0.04 and 5 ohm-cm², between 0.04 and 3 ohm-cm², between 0.04 and 0.5 ohm-cm², between 0.07 and 5 ohm-cm², between 0.07 and 3 ohm-cm² or even between 0.07 and 0.1 ohm-cm².

In some embodiments of the present disclosure, the liquid flow battery may be a redox flow batter}', for example, a vanadium redox flow battery (VRFB), wherein a V³7 V^2÷ sulfate solution serves as the negative electrolyte ("anolyte") and a V⁵7V^4÷ sulfate solution serves as the positive electrolyte ("catholyte"). It is to be understood, however, that other redox chemistries are contemplated and within the scope of the present disclosure, including, but not limited to, V²7V³⁺ vs. BrVClBn, Βη/ΒΓ vs. S/S^2"", BrTBn vs. Zn²7Zn, Ce Ce³⁺ vs. V²7V³⁺, Fe³7Fe²⁺ vs. Bn/Br^", Mn² Mn³⁺ vs. Bn/Br^", Fe 7Fe²⁺ vs. Ti²7Ti⁴⁺ and Cr³7Cr²⁺, acidic/basic chemistries. Other chemistries useful in liquid flow batteries include

coordination chemistries, for example, those disclosed in U.S. Pat. Αρρί, Nos. 2014/0028260, 2014/0099569, and 2014/0193687 and organic complexes, for example, U.S. Pat. Publ. No. 2014/370403 and international application published under the patent cooperation treaty Int. Publ. No. WO 2014/052682, all of which are incorporated herein by reference in their entirety.

In electrochemical cells, electrochemical cell stacks and liquid flow batteries of the present disclosure that contain at least one monopolar plate-electrode assembly of the present disclosure, the components of the cell, cell stack and liquid flow battery (e.g. monopolar plate-electrode assembly, ion permeable membrane, discontinuous transport protection layer, conventional electrode, conventional monopolar plate) may be configured one adjacent to the other in the desired sequence, e.g. a first monopolar plate-electrode assembly, a discontinuous transport protection layer, an ion permeable membrane and a second monopolar piate- electrode assembly, and then held together by mechanical means, for example, by an electrochemical cell frame, an electrochemical ceil stack frame or liquid flow battery frame, as is known in the art.

In electrochemical cells, electrochemical cell stacks and liquid flow batteries of the present disclosure that contain at least one monopolar plate-electrode assembly of the present disclosure, each individual ceil, each individual ceil of a cell stack and each individual cell of a liquid flow battery may be electrically isolated in the non-electrochemically active areas of the cell, as is known in the art. Thus, the perimeter region of a given cell may be electrically isolated from any other given cell.

The electrochemical cells, electrochemical cell stacks and liquid flow batteries of the present disclosure, that contain at least one monopolar plate-electrode assembly of the present disclosure, may be actively cooled. Cooling/heating cells in the stack may be provided, or the reactants may be temperature controlled remotely such as inline heat exchangers or temperature control in the reactant tanks may be provided.

The present disclosure also provides methods of making a monopolar plate-electrode assembly. In some embodiments, the method of making an monopolar plate-electrode assembly includes (i) providing a flow plate substrate having a first major surface and an opposed second major surface in the x-y plane of the monopolar plate-electrode assembly, wherein the first major surface includes at least one flow channel, allowing fluid flow in the x-y plane of the monopolar plate-electrode assembly, the at least one flow channel is in fluid communication with a fluid inlet port and a fluid outlet port of the flow plate substrate, and wherein the flow plate substrate includes at least one via intersecting the channel bottom of the at least one flow channel and the second major surface of the flow plate substrate, (ii) disposing a porous electrode material in at least a portion of the at least one flow channel (iii) disposing an electrically conductive material in at least a portion of the at least one via, wherein the electrically conductive material is in electrical communication with the porous electrode material, thereby forming a monopolar plate-electrode assembly wherein the monopolar plate-electrode assembly exhibits electrical communication through the thickness of the flow plate substrate and does not exhibit fluid communication through the thickness of the flow plate substrate. In another embodiment, the method may further include disposing an electrically conductive layer adjacent to and in contact with the second major surface of the flow plate substrate, wherein the electrically conductive layer is impervious to fluid. In yet another embodiment, the step of disposing a porous electrode material in at least a portion of the at least one flow channel and the step of disposing an electrically conductive material in at least a portion of the at least one via are conducted in a single step.

In some embodiments of the method of making a monopolar plate-electrode assembly, the disposing step or steps may include providing at least one of pressure and heat to at least one of the porous electrode material and/or electrically conductive material.

Providing at least one of pressure and heat to at least one of the porous electrode material and/or electrically conductive material may urge the porous electrode material into the at least one flow channel and/or urge the electrically conductive material into the at least one via. In some embodiments the disposing step includes at least one of coating, e.g. knife coating a polymer, polymer composite or polymer precursor (the polymer precursor may contain electrically conductive particulate); extruding, e.g. melt extruding a polymer, polymer composite or polymer precursor; and printing, e.g. 3-dimensional printing and ink jet printing a polymer, polymer composite or polymer precursor. Coating, e.g. knife coating, and extrusion processes, e.g. polymer melt extrusion, and polymer printing are well known in the art and conventional techniques may be employed in the fabrication of the monopolar plate- electrode assemblies of the present disclosure.

Select embodiments of the present disclosure include, but are not limited to, the following:

In a first embodiment, the present disclosure provides a monopolar plate-electrode assembly comprising:

an electrically conductive material contained in at least a portion of the at least one via, wherein the electrically conductive material is in electrical communication with the porous electrode material; and

wherein the monopolar plate-electrode assembly exhibits electrical communication through the thickness of the flow plate substrate and does not exhibit fluid communication through the thickness of the flow plate substrate.

In a second embodiment, the present disclosure provides a monopolar plate-electrode assembly according to the first embodiment, wherein the flow plate substrate is an electrically conductive flow plate substrate.

In a third embodiment, the present disclosure provides a monopolar plate-electrode assembly according to the second embodiment, wherein the electrically conductive flow plate substrate includes at least one of at least one of a metal, electrically conductive carbon, electrically conductive polymer and electrically conductive polymer composite.

In a fourth embodiment, the present disclosure provides a monopolar plate-electrode assembly according to the first embodiment, wherein the flow plate substrate is a dielectric flow plate substrate.

In a fifth embodiment, the present disclosure provides a monopolar plate-electrode assembly according to the fourth embodiment, wherein the dielectric flow plate substrate includes at least one dielectric polymer.

In a sixth embodiment, the present disclosure provides a monopolar plate-electrode assembly according to the fifth embodiment, wherein the at least one dielectric polymer includes at least one of epoxy resin, phenolic resin, ionic polymer, polyurethane, urea- formadehyde resin, melamine resin, polyester, polyamide, polyether, polycarbonate, polyimide, polysulphone, polyphenylene oxide, polyacrylate, polymethacrylate, polyolefin, styrene and styrene based random and block copolymer, chlorinated polymer, and fluorinated polymer.

In a seventh embodiment, the present disclosure provides a monopolar plate-electrode assembly according to any one of the first through sixth embodiments, wherein the at least one via is a plurality of vias. In an eighth embodiment, the present disclosure provides a monopolar plate-electrode assembly according to any one of the first through seventh embodiments, wherein the at least one via is a plurality of vias, wherein the porous electrode material includes electrically conductive carbon particulate.

In a ninth embodiment, the present disclosure provides a monopolar plate-electrode assembly according to the eighth embodiment, wherein the electrically conductive carbon particulate of the porous electrode material is at least one of carbon particles, carbon flakes, carbon fibers, carbon dendrites, carbon nanotubes and branched carbon nanotubes.

In a tenth embodiment, the present disclosure provides a monopolar plate-electrode assembly according to any one of the first through ninth embodiments, wherein the at least one via is a plurality of vias, wherein the electrically conductive material includes at least one of a metal material, an electrically conductive particulate and an electrically conductive polymer composite comprising polymer and the electrically conductive particulate.

In an eleventh embodiment, the present disclosure provides a monopolar plate- electrode assembly according to the tenth embodiment, wherein the metal of the metal material includes at least one of silver, copper, gold, aluminum, magnesium, molybdenum, iridium, tungsten, zinc, lead, cobalt, nickel, manganese, ruthenium, lithium, iron, tin, platinum, palladium, tantalum, chromium, antimony, vanadium, titanium, zirconium, bismuth, indium, gallium, and cerium.

In a twelfth embodiment, the present disclosure provides a monopolar plate-electrode assembly according to the tenth embodiment, wherein the polymer of the electrically conductive polymer composite includes at least one of polyalkylene, polyacrylate, polymethacrylate, styrene and styrene based random and block copolymer, polyester, polycarbonate, polyamide, polyamide-amine, polyalkylene glycol, polyurethane, polyether, chlorinated polymer; fluoropolymer, polyimide, polyetherimide, polysulphone;

polyphenylene oxides; and polyketone, epoxy resin, phenolic resin, urea-formadehyde resin and melamine resin.

In a thirteenth embodiment, the present disclosure provides a monopolar plate- electrode assembly according to the tenth or twelfth embodiment, wherein the electrically conductive particulate includes at least one of metal particulate, electrically conductive carbon particulate and electrically conductive polymer particulate.

In a fourteenth embodiment, the present disclosure provides a monopolar plate- electrode assembly according to any one of the first through thirteenth embodiments, wherein the electrically conductive material is impervious to fluid.

In a fifteenth embodiment, the present disclosure provides a monopolar plate- electrode assembly according to any one of the first through fourteenth embodiments, wherein the electrically conductive material comprises at least one of an electrically conductive sheet, an electrically conductive pin and a plurality of electrically conductive pins.

In a sixteenth embodiment, the present disclosure provides a monopolar plate- electrode assembly according to any one of the first through fourteenth embodiments, wherein the electrically conductive material comprises at least one of a metal sheet, a metal pin and a plurality of metal pins.

In a seventeenth embodiment, the present disclosure provides a monopolar plate- electrode assembly according to any one of the first through sixteenth embodiments, wherein the flow plate substrate has a thickness from 0.025 cm to 3.2 cm.

In an eighteenth embodiment, the present disclosure provides a monopolar plate- electrode assembly according to any one of the first through seventeenth embodiments, wherein 50 to 100 percent of the volume of the at least one flow channel contains porous electrode material.

In a nineteenth embodiment, the present disclosure provides a monopolar plate- electrode assembly according to any one of the first through eighteenth embodiments, wherein 50 to 100 percent of the volume of the at least one via contains electrically conductive material.

In a twentieth embodiment, the present disclosure provides a monopolar plate- electrode assembly according to any one of the first through nineteenth embodiments further comprising an ion permeable membrane disposed adjacent the first major surface of the flow plate substrate.

In a twenty-first embodiment, the present disclosure provides a monopolar plate- electrode assembly according to the twentieth embodiment, further comprising a

discontinuous transport protection layer disposed between the ion permeable membrane and the first major surface of the flow plate substrate.

In a twenty-second embodiment, the present disclosure provides a monopolar plate- electrode assembly according to any one of the first through twenty-first embodiments further comprising an electrically conductive layer adjacent to and in contact with the second major surface of the flow plate substrate, wherein the electrically conductive layer is impervious to fluid.

In a twenty-third embodiment, the present disclosure provides a method of forming a monopolar plate-electrode assembly comprising:

disposing an electrically conductive material in at least a portion of the at least one via, wherein the electrically conductive material is in electrical communication with the porous electrode material, thereby forming monopolar plate-electrode assembly, wherein the monopolar plate-electrode assembly exhibits electrical communication through the thickness of the flow plate substrate and does not exhibit fluid communication through the thickness of the flow plate substrate.

In a twenty-fourth embodiment, the present disclosure provides an electrochemical cell for a liquid flow battery comprising: two half cells, each half cell including an electrode, wherein at least one of the half cells includes a monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the first through twenty- second embodiments.

In a twenty-fifth embodiment, the present disclosure provides an electrochemical cell for a liquid flow battery according to the twenty -fourth embodiment, wherein the electrode of the at least one half cell, which includes the monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the first through twenty-second embodiments, consists essentially of the porous electrode material of the monopolar plate- electrode assembly.

In a twenty-sixth embodiment, the present disclosure provides a liquid flow battery comprising: at least one electrochemical cell, said electrochemical cell comprising two half cells, each half cell including an electrode, wherein at least one of the half cells includes a monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the first through twenty-second embodiments.

In a twenty-seventh embodiment, the present disclosure provides a liquid flow battery according to the twenty-sixth embodiment, wherein the electrode of the at least one half cell, which includes the monopolar plate-electrode assembly according to any one of the monopolar plate-electrode assemblies of the first through twenty-second embodiments, consists essentially of the porous electrode material of the monopolar plate-electrode assembly.

EXAMPLES

These examples are merely for illustrative purposes only and are not meant to be limiting on the scope of the appended claims. All parts, percentages, ratios, etc. in the examples and the rest of the specification are by weight, unless noted otherwise. Solvents and other reagents used were obtained from Sigma-Aldrich Chemical Company, St. Louis, Missouri unless otherwise noted. All water used was DI water.

Materials

Effective Electrode Resistance Measurement

A monopolar plate-electrode assembly was placed between two graphite plates of a test cell. The flow plates of the test cell were commercially available quad serpentine flow channel with 25 cm² active area, available from Fuel Cell Technologies, Albuquerque, New Mexico. The smooth side of the graphite plates were facing the sample. They were then pressed to the desired compressions by torqueing the bolts to 110 in-lbs torque, compressing the monopolar plate-electrode assembly between the graphite plates. Using power supply TDK - Lambda ZUP 10-40, a constant 35 A current was applied across the sample, and the voltage between the two plates was measured using a KEITHLEY 197 A Autoranging microvolt DMM.

Electrode Solution 1 Preparation

An electrode solution was prepared as follows. Water, 60 ml, was poured into a 500 ml beaker with a teflon coated magnetic stir bar. One drop of Palmolive Original dish soap was added. (Colgate-Palmolive Company, New York). The beaker was placed on a magnetic stir plate and the plate was turned on to a medium setting. TREVIRA 255, 0.2 gm, was added to the beaker and allowed to mix for a minimum of 30 sec to disperse the fibers into the water. ANS, 0.8 gm, was broken up using mortar and pestle, added to solution and allowed to mix for a minimum of 30 sec. Granco XN-100-05M, 1.0 gm, was added to mixture and allowed to mix for a minimum of 30 sec, producing Electrode Solution 1.

Electrode Solution 2 Preparation

The preparation of Electrode Solution 2 followed the Electrode Solution 1

Preparation, except 200 ml of water was used instead of 60 ml water.

Flow Plate Substrate 1 Preparation

Three sheets of polypropylene available under the trade designation

POLYPROPYLENE NATURAL, from Plastics International, Eden Prairie, MN, having dimensions of 0.78 mm thick x 300 mm x 280 mm or two sheet of polyvinylchloride (PVC) available under the trade designation PVC TYPE 1, from Plastics International, Eden Prairie, MN having dimensions of 1.57 mm thick x 300 mm x 280 mm were stacked together and placed on the metal tooling that contained the inverse dimensions of four flow fields, enabling the formation of four flow plate substrates in a single step (once separated via cutting of the polypropylene or the PVC). The flow field pattern of the metal tooling was machined into a plastic substrate that was subsequently metal plated using known techniques. The metal tooling with polypropylene sheets adjacent the flow field pattern were pressed in a compression molder, Rucker PHI 400 ton (City of Industry, CA). The molding conditions used are noted below. Note the "Cure" step is essentially a water cooling step. Temperature H P PreEmboss Cure

control heat

150°C 80,000 lbs 30 120 6 min

second second

The resultant flow fields of each of the four flow plate substrates had the following dimensions after pressing.

Channel length 53.4 mm

Channel width at the top 0.95 mm

Channel width at the bottom 0.73 mm

Channel Depth 0.75 mm

Channel pitch 1.64 mm

Overall channel array width 47.9 mm

Manifold length 51.5 mm

Manifold width 3.15 mm

Manifold Depth 0.75 mm

The length of the manifold is parallel to the channel array width allowing the manifold to be in fluid communication with all of the channels. Vias, having a diameter of 0.43 mm and extending though the thickness of the flow plate substrate, were machined. All the vias were located within a channel and the center-to-center distance, between adjacent vias within a channel, was 2.95 mm. Flow Plate Substrate 2 Preparation

Four sheets of polypropylene available under the trade designation

POLYPROPYLENE NATURAL, from Plastics International, Eden Prairie, MN, having dimensions of 0.78 mm thick x 300 mm x 280 mm were stacked together and placed on the metal tooling that contained the inverse dimensions of four flow fields, enabling the formation of four flow plate substrates in a single step (once separated via cutting of the polypropylene). The flow field pattern of the metal tooling was machined into a plastic substrate that was subsequently metal plated using known techniques. The metal tooling with polypropylene sheets adjacent the flow field pattern were pressed in a compression molder, Rucker PHI 400 ton (City of Industry, CA). The molding conditions used are noted below. Note the "Cure" step is essentially a water cooling step. Temperature H P PreEmboss Cure

control heat

150°C 80,000 lbs 30 120 6 min

second second

Channel length 53.4 mm

Channel width at the top 0.95 mm

Channel width at the bottom 0.73 mm

Channel Depth 0.75 mm

Channel pitch 1.64 mm

Overall channel array width 47.9 mm

Manifold length 51.5 mm

Manifold width 3.15 mm

Manifold Depth 0.75 mm

The length of the manifold is parallel to the channel array width allowing the manifold to be in fluid communication with all of the channels.

The molded flow plate substrate was modified by milling out a 45 mm x 45 mm square, in the land region of the flow plate substrate directly under the channels, leaving only the ribs between the channels. The resultant flow plate substrate had a pocket to place a conductive layer.

Coating Apparatus

The coating apparatus consisted of a clear, plastic tube having a 101 mm inside diameter and a length of 100 mm long; a flow plate substrate holder which was composed of two equal half-cylinders that, when placed adjacent to each other to form a cylinder, had an outside diameter of 101 mm, a length of 63.6 mm and had a 53.2 mm x 62 mm rectangular hole that extended through the length of the cylinder; a plastic frame having a diameter of 101 mm, a thickness of 6.3 mm, a rectangular recess, 1 mm in depth x 71 mm x 63 mm, machined in the middle of the frame and, in the center of the recess, a rectangular hole, 62 mm x 53.2 mm, in which the length and width aligned with the length and width of recess. The plastic frame has four through holes along the perimeter of the rectangular recess, two each adjacent the 63 mm width of the recess. The bottom of each half cylinder of the flow plate substrate holder has two threaded holes that aligned with the through holes of the plastic frame. This enables the half cylinders to be attached to the plastic frame by a set of four screws and, once assembled, also allows the flow plate substrate to be securely held between the plastic frame and flow plate substrate holder.

Example 1

A polypropylene flow plate substrate, prepared as described in the Flow Plate

Substrate 1 Preparation method, was cut into a rectangle, 71 mm x 63 mm, with the flow field channels centered within the rectangle. The flow plate substrate was placed in the recess of the plastic frame of the coating apparatus with the flow fields oriented upwards. The two half cylinders of the flow plate substrate holder were placed on top of the flow plate substrate and attached to the plastic frame via four screws, forming an assembly. Next, the clear plastic tube was placed in a Buchner funnel having an inside diameter of 101 mm. The Buchner funnel is mounted to a 2000 ml vacuum flask. The assembly, was then placed inside the clear plastic tube with the plastic frame oriented adjacent the Buchner funnel bottom. Electrode Solution 1 was then poured into the rectangular hole of the flow plate substrate holder. A 101 mm diameter x 12.9 mm thick disk was then placed on top of the clear tube and the vacuum was turned on. After water stopped dripping from the bottom of the Buchner funnel, the vacuum was turned off and the flow plate substrate, which contained electrode material (ANS and Granco XN-100-05M) from Electrode Solution 1 in both the channels and vias, was carefully removed. The sample was then placed on a metal mesh and placed in an oven to dry at 85°C, producing a monopolar plate-electrode assembly, Example 1. Using the

Effective Electrode Resistance Measurement test, described above, the voltage measured across Example 1 was 0.057 volts.

Example 2

Example 2 included electrically conductive pins in the vias of the flow plate substrate. A PVC flow plate substrate, prepared as described in the Flow Plate Substrate 1 Preparation method, was cut into a rectangle, 71 mm x 63 mm, with the flow field channels centered within the rectangle. Pentel Super Hi-Polymer Lead 0.70 mm - Medium Point - 2B pencil lead was used as the pins and inserted into vias of the flow plate substrate. Once the lead had penetrated through to the opposite side, the lead was broken off. This process was repeated until all the vias had been filled. Next, using a tweezers, the lead was broken off as close to the flow plate substrate surface as possible without removing the lead from the sample. The lead was worn down to the surface of the flow plate substrate by applying pressure to the flow field film sample, and abrasively rubbing it on a piece of paper. As the pencil lead had a larger diameter than the vias, the propylene of the flow plate substrate was deformed during the insertion of the pencil lead into the vias, which allowed the pencil lead to be held firmly in the vias. The channels of the flow plate substrate were then exposed to Electrode Solution 2, using the Coating Apparatus and the general procedure described in Example 1. As the vias had electrically conductive pins in them which prevented solution from flowing through the vias, liquid from Electrode Solution 2 drained from the interior of the apparatus through the seam between the plastic frame and flow plate substrate holder. After water stopped dripping from the bottom of the Buchner funnel, the vacuum was turned off and the flow plate substrate, which contained electrode material (ANS and Granco XN-100-05M) from Electrode Solution 2 in the channels, was carefully removed. The sample was then placed on a metal mesh and placed in an oven to dry at 85°C, producing a monopolar plate-electrode assembly, Example 2. Using the Effective Electrode Resistance Measurement test, described above, the voltage measured across Example 2 was 0.012 volts.

Example 3

A polypropylene flow plate substrate, prepared as described in the Flow Plate

Substrate 2 Preparation method, was cut into a rectangle, 71 mm x 63 mm, with the flow field channels centered within the rectangle. A conductive layer was 45 mm x 45 mm machined sheets of SIGRACELL BIPOLAR PLATE TF6 available from SGL Carbon, GmbH, Meitingen, Germany. The machined sheets were placed in the pocket of the flow plate substrate such that they formed the bottom of the channels and extended to the back side of the molded flow plate substrate, thus providing a portion of the conductive path through the thickness of the flow plate substrate. The flow plate substrate was placed in the recess of the plastic frame of the coating apparatus with the flow fields oriented upwards. The two half cylinders of the flow plate substrate holder were placed on top of the flow plate substrate and attached to the plastic frame via four screws, forming an assembly. Next, the clear plastic tube was placed in a Buchner funnel having an inside diameter of 101 mm. The Buchner funnel is mounted to a 2000 ml vacuum flask. The assembly, was then placed inside the clear plastic tube with the plastic frame oriented adjacent the Buchner funnel bottom. Electrode Solution 1 was then poured into the rectangular hole of the flow plate substrate holder. A 101 mm diameter x 12.9 mm thick disk was then placed on top of the clear tube and the vacuum was turned on. Excess fluid drained from the sample around the flow plate substrate holder and into the Buchner funnel. After water stopped dripping from the bottom of the Buchner funnel, the vacuum was turned off and the flow plate substrate, which contained electrode material (ANS and Granco XN-100-05M) from Electrode Solution 1 in the channels, was carefully removed. The sample was then placed on a metal mesh and placed in an oven to dry at 85°C, producing a monopolar plate-electrode assembly, Example 3. Using the Effective Electrode Resistance Measurement test, described above, the voltage measured across Example 3 was 0.150 volts.

Claims

claimed:

A monopolar plate-electrode assembly comprising:

wherein the monopolar plate-electrode assembly exhibits electrical communication through the thickness of the flow plate substrate and does not exhibit fluid

communication through the thickness of the flow plate substrate.

The monopolar plate-electrode assembly according to claim 1, wherein the flow plate substrate is an electrically conductive flow plate substrate.

The monopolar plate-electrode assembly according to claim 2, wherein the electrically conductive flow plate substrate includes at least one of at least one of a metal, electrically conductive carbon, electrically conductive polymer and electrically conductive polymer composite.

The monopolar plate-electrode assembly according to claim 1, wherein the flow plate substrate is a dielectric flow plate substrate.

The monopolar plate-electrode assembly according to claim 4, wherein the dielectric flow plate substrate includes at least one dielectric polymer.

6. The monopolar plate-electrode assembly according to claim 5, wherein the at least one dielectric polymer includes at least one of epoxy resin, phenolic resin, ionic polymer, polyurethane, urea-formadehyde resin, melamine resin, polyester, polyamide, polyether, polycarbonate, polyimide, polysulphone, polyphenylene oxide, polyacrylate, polymethacrylate, polyolefin, styrene and styrene based random and block copolymer, chlorinated polymer, and fluorinated polymer.

7. The monopolar plate-electrode assembly according to claim 1, wherein the at least one via is a plurality of vias.

8. The monopolar plate-electrode assembly according to claim 1, wherein the porous electrode material includes electrically conductive carbon particulate.

9. The monopolar plate-electrode assembly according to claim 8, wherein the

electrically conductive carbon particulate of the porous electrode material is at least one of carbon particles, carbon flakes, carbon fibers, carbon dendrites, carbon nanotubes and branched carbon nanotubes.

10. The monopolar plate-electrode assembly according to claim 1, wherein the

electrically conductive material includes at least one of a metal material, an electrically conductive particulate and an electrically conductive polymer composite comprising polymer and the electrically conductive particulate.

11. The monopolar plate-electrode assembly according to claim 10, wherein the metal of the metal material includes at least one of silver, copper, gold, aluminum, magnesium, molybdenum, iridium, tungsten, zinc, lead, cobalt, nickel, manganese, ruthenium, lithium, iron, tin, platinum, palladium, tantalum, chromium, antimony, vanadium, titanium, zirconium, bismuth, indium, gallium, and cerium.

12. The monopolar plate-electrode assembly according to claim 10, wherein the polymer of the electrically conductive polymer composite includes at least one of

polyalkylene, polyacrylate, polymethacrylate, styrene and styrene based random and block copolymer, polyester, polycarbonate, polyamide, polyamide-amine,

polyalkylene glycol, polyurethane, polyether, chlorinated polymer; fluoropolymer, polyimide, polyetherimide, polysulphone; polyphenylene oxides; and polyketone, epoxy resin, phenolic resin, urea-formadehyde resin and melamine resin.

13. The monopolar plate-electrode assembly according to claim 10, wherein the

electrically conductive particulate includes at least one of metal particulate, electrically conductive carbon particulate and electrically conductive polymer particulate.

14. The monopolar plate-electrode assembly according to claim 1, wherein the

electrically conductive material is impervious to fluid.

15. The monopolar plate-electrode assembly according to claim 1, wherein the

electrically conductive material comprises at least one of an electrically conductive sheet, an electrically conductive pin and a plurality of electrically conductive pins.

16. The monopolar plate-electrode assembly according to claim 1, wherein the

electrically conductive material comprises at least one of a metal sheet, a metal pin and a plurality of metal pins.

17. The monopolar plate-electrode assembly according to claim 1, wherein the flow plate substrate has a thickness from 0.025 cm to 3.2 cm.

18. The monopolar plate-electrode assembly according to claim 1, wherein 50 to 100 percent of the volume of the at least one flow channel contains porous electrode material.

19. The monopolar plate-electrode assembly according to claim 1, wherein 50 to 100 percent of the volume of the at least one via contains electrically conductive material.

20. The monopolar plate-electrode assembly according to claim 1 further comprising an ion permeable membrane disposed adjacent the first major surface of the flow plate substrate.

21. The monopolar plate-electrode assembly according to claim 20 further comprising a discontinuous transport protection layer disposed between the ion permeable membrane and the first major surface of the flow plate substrate.

22. The monopolar plate-electrode assembly according to claim 1 further comprising an electrically conductive layer adjacent to and in contact with the second major surface of the flow plate substrate, wherein the electrically conductive layer is impervious to fluid.

23. A method of forming a monopolar plate-electrode assembly comprising:

24. An electrochemical cell for a liquid flow battery comprising two half cells, each half cell including an electrode, wherein at least one of the half cells includes a monopolar plate-electrode assembly according to claim 1.

25. The electrochemical cell for a liquid flow battery according to claim 24, wherein the electrode of the at least one half cell, which includes the monopolar plate-electrode assembly according to claim 1, consists essentially of the porous electrode material of the monopolar plate-electrode assembly.

26. A liquid flow battery comprising at least one electrochemical cell, said

electrochemical cell comprising two half cells, each half cell including an electrode, wherein at least one of the half cells includes a monopolar plate-electrode assembly according to claim 1.

27. The liquid flow battery according to claim 26, wherein the electrode of the at least one half cell, which includes the monopolar plate-electrode assembly according to claim

1, consists essentially of the porous electrode material of the monopolar plate- electrode assembly.