SYSTEMS AND METHODS FOR DIRECT COATING OF ELECTRODES ON POROUS SUBSTRATES FOR ELECTROLYZERS

Description

INTRODUCTION

The information provided in this section is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

The present disclosure relates generally to systems and methods for direct coating of electrodes on porous substrates for electrolyzers. Specifically, electrolyzers are devices that perform electrolysis, which is the process of using electricity to split water into oxygen and hydrogen, which may be used as fuel in vehicles, such as automobiles. Electrolyzers consist of an anode and a cathode separated by an electrolyte. Electrolyzers may include a membrane electrode assembly (MEA), which helps produce the electrochemical reaction needed to split water and separate product hydrogen from product oxygen. On the anode side of the MEA, water is electrochemically oxidized into oxygen and proton. The proton diffuses through the membrane and is electrochemically reduced to hydrogen on the cathode side. Catalysts on each side enable reactions and the membrane allows protons to pass through while keeping the gases separate. In this way, the correct level of voltage and current must be applied to the cell to enable gas production.

In a traditional electrolyzer manufacturing, catalyst coated on membrane (CCM) process, multiple decals and multiple lamination processes are required. Accordingly, there is room for improvement in the art to reduce the materials used and the number of sub-processes required.

SUMMARY

One aspect of the disclosure provides a membrane electrode assembly for one of a proton exchange membrane electrolyzer or an alkaline electrolyzer to generate hydrogen for use as fuel in a vehicle, the membrane electrode assembly comprising a corrosion resistant substrate coated with an anode catalyst ink via one of slot die, spray coating methods, or sputtering to form an anode catalyst layer, wherein the anode catalyst layer includes ionomer strands that protrude into the corrosion resistant substrate, a porous substrate coated with a cathode catalyst ink via one of slot die, spray coating methods, or sputtering to form a cathode catalyst layer, wherein the cathode catalyst layer includes ionomer strands that protrude into the porous substrate, and a membrane disposed between the anode catalyst layer of the corrosion resistant substrate and the cathode catalyst layer of the porous substrate.

Implementations of the disclosure may include one or more of the following optional features. In some implementations, the depth of the ionomer strands of the anode catalyst layer protruding into the corrosion resistant substrate may be between approximately 1-80% of the total thickness of the corrosion resistant substrate.

The depth of the ionomer strands of the cathode catalyst layer protruding into the porous substrate may be between approximately 1-80% of the total thickness of the porous substrate.

The corrosion resistant substrate may be a porous transport layer. The porous transport layer may be formed from titanium-based components.

The porous substrate may be a gas diffusion layer. The gas diffusion layer may be formed from carbon-based components.

Another aspect of the disclosure provides a membrane electrode assembly for one of a proton exchange membrane electrolyzer or an alkaline electrolyzer, the membrane electrode assembly comprising a corrosion resistant substrate coated with an anode catalyst ink to form an anode catalyst layer, wherein the anode catalyst layer includes ionomer strands that protrude into the corrosion resistant substrate, a porous substrate coated with a cathode catalyst ink to form a cathode catalyst layer, wherein the cathode catalyst layer includes ionomer strands that protrude into the porous substrate, and a membrane disposed between the anode catalyst layer of the corrosion resistant substrate and the cathode catalyst layer of the porous substrate.

Implementations of the disclosure may include one or more of the following optional features. In some implementations, the depth of the ionomer strands of the anode catalyst layer protruding into the corrosion resistant substrate may be between approximately 1-80% of the total thickness of the corrosion resistant substrate.

The depth of the ionomer strands of the cathode catalyst layer protruding into the porous substrate may be between approximately 1-80% of the total thickness of the porous substrate.

The corrosion resistant substrate may be a porous transport layer. The porous transport layer may be formed from titanium-based components.

The porous substrate may be a gas diffusion layer. The gas diffusion layer may be formed from carbon-based components.

Another aspect of the disclosure provides a method for making a membrane electrode assembly comprising providing a corrosion resistant substrate, providing a membrane, providing a porous substrate, applying an anode catalyst ink to the corrosion resistant substrate, applying a cathode catalyst ink to the porous substrate, and laminating the corrosion resistant substrate coated with the anode catalyst ink and the porous substrate coated with the cathode catalyst ink with the membrane.

Implementations of the disclosure may include one or more of the following optional features. In some implementations, the anode catalyst ink may include ionomer strands that protrude into the corrosion resistant substrate, and the depth of the ionomer strands protruding into the corrosion resistant substrate may be between approximately 1-80% of the total thickness of the corrosion resistant substrate.

The cathode catalyst ink may include ionomer strands that protrude into the porous substrate, and the depth of the ionomer strands protruding into the porous substrate may be between approximately 1-80% of the total thickness of the porous substrate.

The corrosion resistant substrate may be a porous transport layer. The porous transport layer may be formed from titanium-based components.

The porous substrate may be a gas diffusion layer.

The details of one or more implementations of the disclosure are set forth in the accompanying drawings and description below. Other aspects, features, and advantages will be apparent from the description, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustrative purposes only of selected configurations and are not intended to limit the scope of the present disclosure.

FIG. 1 is a side view schematic of a membrane electrode assembly (MEA) in accordance with principles of the present disclosure;

FIG. 2 is a side exploded view of the MEA of FIG. 1;

FIG. 3 is a schematic illustrating a method of manufacturing the MEA of FIG. 1; and

FIG. 4 is a flowchart method of manufacturing the MEA of FIG. 1.

Corresponding reference numerals indicate corresponding parts throughout the drawings.

DETAILED DESCRIPTION

Example configurations will now be described more fully with reference to the accompanying drawings. Example configurations are provided so that this disclosure will be thorough, and will fully convey the scope of the disclosure to those of ordinary skill in the art. Specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of configurations of the present disclosure. It will be apparent to those of ordinary skill in the art that specific details need not be employed, that example configurations may be embodied in many different forms, and that the specific details and the example configurations should not be construed to limit the scope of the disclosure.

The terminology used herein is for the purpose of describing particular exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. Additional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,” “connected to,” “attached to,” or “coupled to” another element or layer, it may be directly on, engaged, connected, attached, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” “directly attached to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

The terms “first,” “second,” “third,” etc. may be used herein to describe various elements, components, regions, layers and/or sections. These elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example configurations.

Referring to FIGS. 1 and 2, a membrane electrode assembly (MEA) 100 is generally shown. The MEA 100 may be incorporated into a proton exchange membrane (PEM) electrolyzer or an alkaline electrolyzer. Any of the aforementioned electrolyzers may be configured to split water into oxygen and hydrogen, which may be used as fuel in vehicles, such as automobiles, or fuel in any other suitable application. The MEA 100 includes a membrane 102, a corrosion resistant porous substrate 104, and a porous substrate 106.

The membrane 102 may use PFSA or non-PFSA ionomer materials. The membrane 102 can have reinforcement materials such as expanded polytetrafluoroethylene (ePTFE) or any other suitable materials for mechanical support. Any reinforcement materials of the membrane 102 may form a reinforcement layer, which may have a reinforcement layer thickness between 0-100% of the total thickness of the membrane 102.

The membrane 102 may have gas recombination catalysts (GRC), such as Platinum, Platinum on Carbon, Platinum on others, or other additives. Any GRC of the membrane 102 may form a gas recombination layer (GRL) having a GRL thickness between 0-100% of the total thickness of the membrane 102. The membrane 102 may include chemical mitigation additives, such as Cerium, Manganese, Cobalt, etc., in different format of chemical compounds.

The corrosion resistant substrate 104 may be a porous transport layer (PTL) or any other suitable substrate. The corrosion resistant substrate 104 may be formed from titanium-based components, such as sintered titanium particle substrates, titanium fiber paper, expanded titanium mesh, or any other suitable material. The corrosion resistant substrate 104 is designed to be porous and conductive, both in-plane and through plane. The corrosion resistant substrate 104 is configured to receive and be coated with an anode catalyst ink to form an anode catalyst layer 108. The anode catalyst layer 108 primarily includes both catalyst and binder. Ionomer, in addition to proton conducting function, acts as a binder in most cases. In some implementations, the anode catalyst layer 108 may include ionomer strands protruding into the corrosion resistant substrate 104. The depth of the ionomer strands of the anode catalyst layer 108 protruding into the corrosion resistant substrate 104 is between approximately 1-80% of the total thickness of the corrosion resistant substrate 104. In other implementations, the anode catalyst layer 108 and its components such as catalyst, binder (e.g., Ionomer) may be adjacent to, but not protrude into, the corrosion resistant substrate 104. The anode catalyst layer 108 may be applied to the corrosion resistant substrate 104 via slot die, spray coating methods, sputtering, or any other suitable method.

The porous substrate 106 may be a gas diffusion layer (GDL) or any other suitable substrate. The porous substrate 106 may be formed from carbon-based components, such as carbon cloth, carbon paper, and/or any other suitable material. The porous substrate 106 is configured to receive and be coated with a cathode catalyst ink to form a cathode catalyst layer 110. In some implementations, the cathode catalyst layer 110 includes ionomer strands protruding into the porous substrate 106. The depth of the ionomer strands of the cathode catalyst layer 110 protruding into the porous substrate 106 is between approximately 1-80% of the total thickness of the porous substrate 106. In other implementations, the cathode catalyst layer 110 and its components such as catalyst, binder (e.g., Ionomer) may be adjacent to, but not protrude into, the porous substrate 106. The cathode catalyst layer 110 may be applied to the porous substrate 106 via slot die, spray coating methods, sputtering, or any other suitable method.

Referring to FIG. 3, the MEA 100 may be manufactured via lamination. Specifically, the corrosion resistant substrate 104 is coated with the anode catalyst ink to form the anode catalyst layer 108, and the porous substrate 106 is coated with the cathode catalyst ink to form the cathode catalyst layer 110. Then, the corrosion resistant substrate 104 coated with the anode catalyst layer 108 and the porous substrate 106 coated with the cathode catalyst layer 110 are laminated with the membrane 102 and held in place by gasket 112. In some implementations, the gasket 112 may be between the membrane 102 and the anode catalyst layer 108 or the gasket 112 may be between the membrane 102 and the cathode catalyst layer 110.

Referring to FIG. 4, a method 200 for manufacturing the MEA 100 is generally shown. At step 202, the corrosion resistant substrate 104 or PTL is provided. At step 204, the membrane 102 is provided. At step 206, the porous substrate 106 or GDL is provided. At step 208, the anode catalyst ink is applied to the corrosion resistant substrate 104 to form the anode catalyst layer 108. At step 210, the cathode catalyst ink is applied to the porous substrate 106 to form the cathode catalyst layer 110. At step 212, the gasket 112 is provided. At step 214, the corrosion resistant substrate 104 coated with the anode catalyst layer 108 and the porous substrate 106 coated with the cathode catalyst layer 110 are laminated with the membrane 102 using the gasket 112 to form the MEA 100.

During the manufacture of traditional MEAs, an anode catalyst ink and a cathode catalyst ink are both coated on separate decals, laminated with a membrane, and then the decals are removed. Subsequently, an adhesive is screen printed or dispensed on the outer edges of a PTL or GDL substrates. Later, the PTL or GDL are pressed or laminated against catalyst coated membranes. Finally, the entire assembly is laminated to form the MEA. The MEA 100 and method 200 of manufacturing the same as described herein eliminates the intermediate lamination step, application of adhesive on PTL or GDL, and eliminates the need for additional decals. In some implementations, one or more portions of the MEA 100 (e.g., the cathode side) and method 200 of manufacturing the same may implement portions of the traditional process.

A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

The foregoing description has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular configuration are generally not limited to that particular configuration, but, where applicable, are interchangeable and can be used in a selected configuration, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.