阅读说明：本技术 具有激光诱导表面改性集流体的电极组件及其制造方法 (Electrode assembly with laser-induced surface modification current collector and method of manufacturing the same ) 是由 戴放 王宏亮 陈书如 Q·张 蔡梅 于 2020-11-27 设计创作，主要内容包括：本申请涉及具有激光诱导表面改性集流体的电极组件及其制造方法。在本文中提供了用于电化学电池的电极组件。所述电极组件包括具有第一表面的集流体、设置在所述集流体的第一表面上的金属氧化物层、和结合到所述集流体的第一表面上的含锂层。所述金属氧化物层包括多个特征。在本文中还提供了制造此类电极组件的方法。所述方法包括在氧的存在下将激光束引向所述集流体的第一表面以在所述第一表面上形成金属氧化物层,并将含锂层施加到所述金属氧化物层上,由此将含锂层与集流体结合。(The present application relates to an electrode assembly having a laser-induced surface modified current collector and a method of manufacturing the same. Provided herein are electrode assemblies for electrochemical cells. The electrode assembly includes a current collector having a first surface, a metal oxide layer disposed on the first surface of the current collector, and a lithium-containing layer bonded to the first surface of the current collector. The metal oxide layer includes a plurality of features. Methods of making such electrode assemblies are also provided herein. The method includes directing a laser beam toward a first surface of the current collector in the presence of oxygen to form a metal oxide layer on the first surface, and applying a lithium-containing layer onto the metal oxide layer, thereby bonding the lithium-containing layer to the current collector.)

1. An electrode assembly for an electrochemical cell, comprising:

a current collector having a first surface, wherein the current collector comprises a metal;

a metal oxide layer disposed on the first surface of the current collector, wherein the metal oxide layer comprises a plurality of features; and

a lithium-containing layer bonded to the first surface of the current collector.

2. The electrode assembly of claim 1, wherein the metal is selected from the group consisting of copper, nickel, titanium, iron, molybdenum, chromium, and combinations thereof, and the metal oxide is selected from the group consisting of copper oxide, nickel oxide, titanium oxide, iron oxide, molybdenum oxide, chromium oxide, and combinations thereof.

3. The electrode assembly of claim 1, wherein the bonding is mechanical bonding, chemical bonding, or a combination thereof.

4. The electrode assembly of claim 1, wherein the plurality of features is a plurality of mechanical interlocking features that form a mechanical bond with the lithium-containing layer.

5. The electrode assembly of claim 1, further comprising a bonding layer disposed between a lithium-containing layer and a metal oxide layer, wherein the bonding layer chemically bonds a lithium-containing layer to a metal oxide layer, wherein the bonding layer comprises a lithium oxide, the metal, or a combination thereof.

6. The electrode assembly of claim 1, wherein the lithium-containing layer is a lithium foil or a lithium film.

7. A lithium-containing electrochemical cell comprising:

a negative electrode assembly, comprising:

a current collector having a first surface, wherein the current collector comprises a metal;

a metal oxide layer disposed on the first surface of the current collector, wherein the metal oxide layer comprises a plurality of features; and

a lithium-containing layer bonded to the first surface of the current collector, wherein the bond between the lithium-containing layer and the first surface is a mechanical bond, a chemical bond, or a combination thereof;

a positive electrode assembly spaced apart from the negative electrode assembly;

a porous separator disposed between opposing surfaces of the negative electrode assembly and the positive electrode assembly; and

a liquid electrolyte infiltrating the negative electrode assembly, the positive electrode assembly, and the porous separator.

8. The lithium-containing electrochemical cell of claim 7, wherein the metal is selected from the group consisting of copper, nickel, titanium, iron, molybdenum, chromium, and combinations thereof, the metal oxide is selected from the group consisting of copper oxide, nickel oxide, titanium oxide, iron oxide, molybdenum oxide, chromium oxide, and combinations thereof, and the lithium-containing layer is a lithium foil or a lithium film.

9. The lithium-containing electrochemical cell of claim 7, wherein the plurality of features is a plurality of mechanical interlocking features that form a mechanical bond with the lithium-containing layer.

10. The lithium-containing electrochemical cell of claim 7, wherein the negative electrode assembly further comprises a bonding layer disposed between the lithium-containing layer and the metal oxide layer, wherein the bonding layer chemically bonds the lithium-containing layer to the metal oxide layer, wherein the bonding layer comprises lithium oxide, the metal, or a combination thereof.

Technical Field

The present application relates to an electrode assembly having a laser-induced surface modified current collector, a method of manufacturing the same, and an electrochemical cell including the same.

Background

This section provides background information related to the present disclosure that is not necessarily prior art.

High energy density electrochemical cells (cells), such as lithium ion batteries (batteries), may be used in various consumer products and vehicles, such as Hybrid Electric Vehicles (HEVs) and Electric Vehicles (EVs). A typical lithium ion battery includes a first electrode (e.g., a cathode), a second electrode of opposite polarity (e.g., an anode), an electrolyte material, and a separator. Conventional lithium ion batteries operate by reversibly transferring lithium ions between a negative electrode and a positive electrode. The separator and the electrolyte are disposed between the negative electrode and the positive electrode. The electrolyte is suitable for conducting lithium ions and may be in solid or liquid form. During battery charging, lithium ions move from the cathode (positive electrode) to the anode (negative electrode) and in the opposite direction as the battery discharges. For convenience, the negative electrode will be used synonymously with the anode, although as recognized by those skilled in the art, during certain phases of the lithium ion cycle, the anode function may be associated with the positive electrode rather than the negative electrode (e.g., the negative electrode may be the anode when discharged and the cathode when charged).

Many different materials may be used to fabricate components for lithium ion batteries. Common negative electrode materials include lithium intercalation materials or alloy host materials, such as carbon-based materials, e.g., lithium-graphite intercalation compounds, or lithium-silicon compounds, lithium-tin alloys, and Lithium Titanate (LTO) (e.g., Li)_4+xTi₅O₁₂Where 0. ltoreq. x.ltoreq.3, e.g. Li₄Ti₅O₁₂). The negative electrode may also be fabricated from metallic lithium, commonly referred to as a Lithium Metal Anode (LMA), so that the electrochemical cell is considered a lithium metal battery or cell. The use of metallic lithium in the negative electrode of a rechargeable battery has various potential advantages, including having the highest theoretical capacity and the lowest electrochemical potential. Thus, batteries incorporating lithium metal anodes can have higher energy densities (potentially doubling the storage capacity and halving the size of the battery) while maintaining similar cycle life as other lithium ion batteries. Lithium metal batteries are therefore one of the most promising candidates for high energy storage systems.

However, lithium metal batteries also have potential drawbacks in some cases. For example, the relatively high level of reactivity of lithium metal can lead to interfacial instability and undesirable side reactions. Side reactions may occur between lithium metal and various species to which lithium metal may be exposed during the manufacture and/or operation of an electrochemical cell. Such side reactions may promote undesirable dendrite formation. Another potential cause of performance degradation in lithium metal batteries may result from poor long-term adhesion of lithium metal to the metal current collector of the negative electrode. In some cases, such weak long-term adhesion may result in undesirable increases in resistance and impedance during cycling of the battery.

It is therefore desirable to develop reliable high performance lithium-containing negative electrode materials for use in high energy electrochemical cells and methods related thereto that improve long term adhesion between lithium metal and metal current collectors.

Disclosure of Invention

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

The present disclosure relates to an electrode assembly having a laser-induced surface modified current collector and a method of manufacturing the electrode assembly.

In certain aspects, provided herein are methods of making an electrode assembly for an electrochemical cell. The method includes directing a laser beam in the presence of oxygen toward a first surface of a current collector comprising a metal to form a metal oxide layer on the first surface. The metal oxide layer includes a plurality of features (features). The method further includes applying a lithium-containing layer to the metal oxide layer. The lithium-containing layer forms a bond (bond) with the first surface of the current collector.

The metal may be selected from the group consisting of copper, nickel, titanium, iron, molybdenum, chromium, and combinations thereof, and the metal oxide may be selected from the group consisting of copper oxide, nickel oxide, titanium oxide, iron oxide, molybdenum oxide, chromium oxide, and combinations thereof.

The laser beam may have a power of greater than or equal to about 50W, a scan speed of greater than or equal to about 1 mm/s, and a spot size (spot size) of greater than or equal to about 20 μm.

Directing a laser beam toward a first surface of a current collector may include moving the laser beam relative to the current collector to create the plurality of features on the first surface.

The bonding between the lithium-containing layer and the first surface of the current collector may be mechanical bonding (mechanical bonding), chemical bonding (chemical bonding), or a combination thereof.

The plurality of features may be a plurality of mechanical interlocking features that form a mechanical bond with the lithium-containing layer.

Heat (heat) may be applied to the lithium-containing layer before the lithium-containing layer is applied to the metal oxide layer, while the lithium-containing layer is applied to the metal oxide layer, after the lithium-containing layer is applied to the metal oxide layer, or a combination thereof.

A bonding layer may be formed between the lithium-containing layer and the metal oxide layer. The bonding layer chemically bonds the lithium-containing layer to the metal oxide layer, and the bonding layer comprises lithium oxide, the metal, or a combination thereof.

The lithium-containing layer may be a lithium foil or a lithium film.

In still other aspects, provided herein are electrode assemblies for electrochemical cells. The electrode assembly includes a current collector having a first surface, a metal oxide layer disposed on the first surface of the current collector, and a lithium-containing layer bonded to the first surface of the current collector. The current collector includes a metal, and the metal oxide layer includes a plurality of features.

The metal may be selected from the group consisting of copper, nickel, titanium, iron, molybdenum, chromium, and combinations thereof, and the metal oxide may be selected from the group consisting of copper oxide, nickel oxide, titanium oxide, iron oxide, molybdenum oxide, chromium oxide, and combinations thereof.

The bonding between the lithium-containing layer and the first surface of the current collector may be mechanical bonding, chemical bonding, or a combination thereof.

The plurality of features may be a plurality of mechanical interlocking features that form a mechanical bond with the lithium-containing layer.

The negative electrode assembly may further include a bonding layer disposed between the lithium-containing layer and the metal oxide layer. The bonding layer chemically bonds the lithium-containing layer to the metal oxide layer, and the bonding layer comprises lithium oxide, the metal, or a combination thereof.

The lithium-containing layer may be a lithium foil or a lithium film.

In still other aspects, provided herein are lithium-containing electrochemical cells. The lithium-containing electrochemical cell includes a negative electrode assembly, a positive electrode assembly spaced apart from the negative electrode assembly, a porous separator disposed between opposing surfaces of the negative electrode assembly and the positive electrode assembly, and a liquid electrolyte impregnating the negative electrode assembly, the positive electrode assembly, and the porous separator. The negative electrode assembly includes a current collector having a first surface, a metal oxide layer disposed on the first surface of the current collector, and a lithium-containing layer bonded to the first surface of the current collector. The current collector includes a metal, and the metal oxide layer includes a plurality of features.

The metal may be selected from the group consisting of copper, nickel, titanium, iron, molybdenum, chromium, and combinations thereof, and the metal oxide may be selected from the group consisting of copper oxide, nickel oxide, titanium oxide, iron oxide, molybdenum oxide, chromium oxide, and combinations thereof. The lithium-containing layer may be a lithium foil or a lithium film.

The bonding between the lithium-containing layer and the first surface of the current collector may be mechanical bonding, chemical bonding, or a combination thereof.

The plurality of features may be a plurality of mechanical interlocking features that form a mechanical bond with the lithium-containing layer.

The negative electrode assembly may further include a bonding layer disposed between the lithium-containing layer and the metal oxide layer. The bonding layer chemically bonds the lithium-containing layer to the metal oxide layer, and the bonding layer comprises lithium oxide, the metal, or a combination thereof.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

Drawings

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

Fig. 1A is a cross-sectional view of an electrode assembly according to one aspect of the present disclosure.

Fig. 1B is an exploded view of a portion of the electrode assembly of fig. 1A.

Fig. 1C is a cross-sectional view of an electrode assembly according to another aspect of the present disclosure.

Fig. 2 is a cross-sectional view of a lithium-containing electrochemical cell according to one aspect of the present disclosure.

Fig. 3 is an illustration of a method of manufacturing an electrode assembly for an electrochemical cell according to one aspect of the present disclosure.

Fig. 4 is an illustration of a method of manufacturing an electrode assembly for an electrochemical cell according to another aspect of the present disclosure.

Fig. 5A is a Scanning Electron Microscope (SEM) image of the surface of the copper current collector after a portion has been laser processed according to one aspect of the present disclosure.

Fig. 5B is an enlarged view of the SEM image of fig. 5A of the laser-treated portion of the copper current collector.

Fig. 6A depicts the etch time(s) vs atomic percent (%) of the untreated portion of the copper current collector and the laser treated portion of the copper current collector depicted in fig. 5A.

Fig. 6B depicts the binding energy (eV) vs counts/sec for the untreated portion of the copper current collector depicted in fig. 5A.

Fig. 6C depicts the binding energy (eV) vs counts/sec for the laser processed portion of the copper current collector depicted in fig. 5A.

Fig. 7A is a photograph of a lithium-based electrode assembly prepared according to the present disclosure after a peel test.

Fig. 7B is a photograph of a conventional lithium-based electrode assembly after a peel test.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Detailed Description

The exemplary embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those skilled in the art. Numerous specific details are set forth such as examples of specific compositions, components, devices, and methods to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some exemplary embodiments, well-known methods, well-known device structures, and well-known techniques have not been described in detail.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "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 stated features, elements, components, steps, integers, operations, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. While the open-ended term "comprising" should be understood as a non-limiting term used to describe and claim the various embodiments described herein, in certain aspects the term is instead understood to be a more limiting and limiting term such as "consisting of … …" or "consisting essentially of … …". Thus, for any given embodiment that recites a composition, material, component, element, feature, integer, operation, and/or process step, the disclosure also specifically includes embodiments that consist of, or consist essentially of, such recited composition, material, component, element, feature, integer, operation, and/or process step. In the case of "consisting of … …, alternative embodiments exclude any additional compositions, materials, components, elements, features, integers, operations, and/or process steps, and in the case of" consisting essentially of … …, "exclude from such embodiments any additional compositions, materials, components, elements, features, integers, operations, and/or process steps that substantially affect the basic and novel characteristics, but may include in such embodiments any compositions, materials, components, elements, features, integers, operations, and/or process steps that do not substantially affect the basic and novel characteristics.

Any 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. It is also to be understood that additional or alternative steps may be used, unless otherwise stated.

When a component, element, or layer is referred to as being "on," "engaged to," "connected to," or "coupled to" another element or layer, it may be directly on, engaged, connected, 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 another element or layer, "directly engaged", "directly connected", or "directly coupled" to the other 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 similar manner (e.g., "between.. vs" directly between.., "adjacent" vs "directly adjacent," etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

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

For ease of description, spatially and temporally relative terms, such as "before", "after", "inside", "outside", "below", "lower", "upper", "lower", and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Spatially and temporally relative terms may be intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the figures.

Throughout this disclosure, numerical values represent approximate measurements or range limits to include embodiments that deviate slightly from the given value and that generally have the listed values, as well as embodiments that have exactly the listed values. Other than in the examples provided at the end of the detailed description, all numerical values of parameters (such as amounts or conditions) in this specification (including the appended claims) are to be understood as being modified in all instances by the term "about", whether or not "about" actually appears before the numerical value. By "about" is meant that the numerical value allows some slight imprecision (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If the imprecision provided by "about" is not otherwise understood in the art with this ordinary meaning, then "about" as used herein at least refers to variations that may result from ordinary methods of measuring and using such parameters. For example, "about" may encompass variations of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in certain aspects optionally less than or equal to 0.1%.

In addition, the disclosure of a range includes all values within the full range and further sub-ranges, including the endpoints and sub-ranges given for these ranges.

Exemplary embodiments will now be described more fully with reference to the accompanying drawings.

The present technology contemplates an electrode assembly or assembly for an electrochemical cell and a method of making the same. The electrochemical cell may comprise, for example, a battery, a capacitor or a supercapacitor. Suitable batteries may include lithium ion, lithium sulfur, and lithium-lithium symmetric batteries. High energy density electrochemical cells, such as lithium-based batteries, are useful in a variety of consumer products. In a wide variety of situations, such electrochemical cells are used in vehicular applications. However, the present techniques may also be used in a wide variety of other applications. For example, devices in which such electrochemical cells may be used include electric motors for hybrid or all-electric vehicles, laptops, tablets, mobile phones, and cordless power tools or appliances.

In various aspects, the present disclosure provides an electrode assembly, such as a lithium-based (Li-based) negative electrode assembly, and methods of forming related thereto. The electrode assembly includes a current collector including a metal and having a first surface, and a metal oxide layer disposed on the first surface of the current collector. An electroactive lithium-containing layer can be disposed on or bonded to the first surface of the current collector. The metal in the metal current collector is optionally selected from: copper (Cu), nickel (Ni), iron (Fe), titanium (Ti), chromium (Cr), molybdenum (Mo), and combinations thereof. For example, the current collector may be formed of an iron alloy (e.g., stainless steel). Copper and nickel are particularly challenging metal substrates on which to form lithium-containing layers because such metals typically do not react with lithium at room temperature and have significant nucleation overpotentials (nucleation overpotentials). Current techniques for forming lithium-containing layers on such metallic current collectors typically involve treating the current collector with strong solvents (e.g., toluene or acetone) and acids (e.g., sulfuric acids). Such techniques typically involve multiple laborious processing steps, and even after processing, the adhesive strength between the lithium-containing layer and the current collector may be low. If the bond between the lithium metal and the current collector is weak, the resistance and impedance of the electrode will increase over time. Electrode assemblies formed according to various aspects of the present disclosure advantageously have improved adhesion between the lithium-containing layer and the current collector.

One example of an electrode assembly 100 formed according to various methods of the present disclosure described below is shown in fig. 1A. The electrode assembly 100 includes a current collector 30 having a first surface 32. The current collector 30 is substantially parallel to the lithium-containing layer 50 and the metal oxide layer 35 disposed therebetween, the metal oxide layer 35 bonding the current collector 30 to the lithium-containing layer 50. The metal oxide layer 35 is disposed on the first surface 32 of the current collector 30. The metal oxide layer 35 bonds and/or connects the lithium-containing layer 50 and the current collector 30 to form the electrode assembly 100. In any embodiment, the bond between the lithium-containing layer 50 and the current collector 30 may be a mechanical bond, a chemical bond, or a combination thereof. In certain aspects, the electrode assembly 100 may be a lithium-based negative electrode assembly.

In certain variations, the current collector 30 is a film or foil having a thickness of about 1 μm to about 25 μm, and in certain aspects optionally about 5 μm to about 10 μm. The lithium-containing layer 50 can be a lithium film or foil and can have an applied thickness of about 1 μm to about 20 μm, and in certain aspects optionally about 2 μm to about 10 μm. As will be understood by those skilled in the art, the thickness of the lithium-containing layer 50 may increase during cycling of an electrochemical cell containing the electrode assembly 100. For example, lithium present in the electrochemical cell may be plated onto the lithium-containing layer 50. Thus, the lithium-containing layer 50 may provide a thin initiation layer (initiator layer) or strike-plate layer that facilitates subsequent growth of lithium that may migrate from the electroactive material of the incorporated electrode or electrolyte system. While the thickness of the metal oxide layer 35 can vary depending on the parameters of the method of forming the same, in various instances, the metal oxide layer 35 can have a thickness of about 5 nm to about 5 μm, and optionally in certain aspects about 0.02 μm to about 1 μm.

The setThe fluid 30 may comprise a metal selected from the group consisting of: copper (Cu), nickel (Ni), iron (Fe), titanium (Ti), chromium (Cr), molybdenum (Mo), and combinations thereof. In some embodiments, the metal may be formed from a ferrous alloy, such as stainless steel. The metal oxide layer 35 comprises a metal oxide formed, for example, by exposing the first surface 32 of the current collector 30 to oxygen. The metal oxide may be selected from copper oxides (e.g. Cu)₂O、CuO、CuO₂、Cu₂O₃) Nickel oxide (e.g. NiO, Ni)₂O₃) Titanium oxide (e.g., TiO)₂、TiO、Ti₂O₃、Ti₃O、Ti₂O、Ti_nO_2n-1Where n is 3-9 inclusive), iron oxides (e.g., FeO)₂、Fe₃O₄、Fe₄O₅、Fe₅O₆、Fe₅O₇、Fe₂₅O₃₂、Fe₁₃O₁₉、Fe₂O₃) Chromium oxide (e.g. CrO, Cr)₂O₃、CrO₂、CrO₃、CrO₅、Cr₈O₂₁) Molybdenum oxide (MoO)₂、MoO₃、Mo₈O₂₃、Mo₁₇O₄₇) And one or more combinations thereof.

As shown in fig. 1B, the metal oxide layer 35 also includes a plurality of features 45. The features 45 may be in the shape of substantially triangular peaks with valleys 47 disposed between the features 45. In some embodiments, the features 45 may have a substantially uniform shape, or the shapes may be non-uniform and define the same or different shapes. Similarly, the valleys 47 may have a substantially uniform shape, or the shapes may be non-uniform and define the same or different shapes. In any embodiment, the plurality of features 45 may be a plurality of mechanical interlocking features that form a mechanical bond with the lithium-containing layer 50 such that the lithium-containing layer 50 has improved adhesion to the current collector 30. For example, the plurality of features 45, which are a plurality of mechanical interlocking features, may be understood as a type of groove configuration such that the lithium-containing layer 50 interlocks with the features 45 and valleys 47 of the metal oxide layer 35, thereby forming a mechanical bond between the lithium-containing layer 50 and the current collector 30. It is contemplated herein that other mechanical interlocking shapes and designs may be used to interlock components together. For example, complementary protruding flanges, grooves, channels, locking wings of different shapes may be used as mechanical interlocking features. For example, the one or more interlocking features may define a triangular region, a quadrilateral region, an annular region, a curved-shape region, or a combination thereof. The valleys 47 may define triangular regions, quadrilateral regions, annular regions, curved shaped regions, or combinations thereof.

Additionally or alternatively, the electrode assembly may further comprise a bonding layer disposed between the lithium-containing layer and the current collector. For example, as shown in fig. 1C, in the electrode assembly 110, the bonding layer 37 may be disposed between the lithium containing layer 50 and the metal oxide layer 35. The bonding layer 37 may advantageously form a chemical bond between the lithium-containing layer 50 and the metal oxide layer 35, thereby providing further improved adhesion between the lithium-containing layer 50 and the current collector 30. As described further below, the bonding layer 37 may be formed when the lithium-containing layer 50 is heated and applied to the current collector 30. Thus, the bonding layer 37 may comprise lithium oxide (e.g., LiO)₂) And metal from current collector 30. For example, depending on the composition of current collector 30, the metal in the bond layer 37 may be selected from copper (Cu), nickel (Ni), iron (Fe), titanium (Ti), chromium (Cr), molybdenum (Mo), and combinations thereof. Although the bonding layer 37 is shown as a continuous discrete layer in fig. 1C, it is contemplated herein that the bonding layer 37 may be discontinuous and/or mixed or dispersed with the metal oxide layer 35.

In various aspects, electrochemical cells for use in a battery (e.g., a lithium ion battery or a lithium sulfur battery) or as a capacitor are provided herein. The electrochemical cell may include an electrode assembly as described herein. For example, as best shown in fig. 2, a lithium-containing electrochemical cell 300 (also referred to herein as "electrochemical cell 300" or "cell 300") of a lithium-ion battery (not shown) includes a negative electrode assembly 312, a positive electrode assembly 315, a porous separator 316, and a liquid electrolyte 318 that impregnates, wets, or wets the surfaces of at least a portion of the negative electrode assembly 312, a portion of the positive electrode assembly 315, and the porous separator 316, respectively, and fills the pores. The negative electrode current collector 30 described herein is disposed adjacent to and in electrical connection with the lithium-containing layer 50 described herein. The current collector 30 has a first surface 32, and a metal oxide layer 35 as described herein may be disposed on the first surface 32 of the current collector 30. The metal oxide layer 35 includes a plurality of features (not shown) as described herein. The lithium-containing layer 50 is bonded to the first surface 32 of the current collector 30 as described herein. Optionally, the negative electrode assembly 312 includes a bonding layer 37 described herein disposed between the lithium-containing layer 50 and the metal oxide layer 35.

The positive electrode assembly 315 is spaced apart from the negative electrode assembly 312. The positive electrode assembly 315 includes a positive electrode current collector 322 disposed adjacent to and electrically connected to the positive electrode layer 314. Positive electrode layer 314 may be coated, deposited, or otherwise formed on a major surface of positive electrode current collector 322. With respect to the position of separator 316, negative electrode assembly 312 includes a front surface 324 and positive electrode assembly 315 includes a front surface 328. When assembled, the front surfaces 324, 328 of the negative and positive electrode assemblies 312, 315 are opposed to each other, and the separator 316 is sandwiched between the opposed front surfaces 324, 328 of the negative and positive electrode assemblies 312, 315. In particular, the separator 316 includes a first side 332 facing the negative electrode assembly 312 and an opposite second side 334 facing the positive electrode assembly 315.

The electrochemical cell 300 may have a thickness of about 100 μm to about 1 mm, as measured from an outer surface of the negative electrode current collector 30 to an opposite outer surface of the positive electrode current collector 322. Separately, the current collectors 30, 322 may have a thickness of about 20 μm, and the porous separator 316 may have a thickness of about 25 μm.

In certain other variations, the electrochemical cell may be a supercapacitor, such as a lithium ion-based supercapacitor.

In various aspects, the present disclosure provides methods of forming the electrode assemblies described above. For example, as shown in FIG. 3, the methodThe method includes directing a laser beam 15 from a laser source 10 toward a first surface (e.g., first surface 32) of a current collector (e.g., current collector 30) as described herein that includes a metal as described herein. The laser beam 15 may be directed toward the first surface 32 of the current collector 30 via a laser head 20, such as a scanning head or scanner (e.g., one-dimensional (1D) scanner, two-dimensional scanner (2D)). The method may be performed in the presence of oxygen to form a metal oxide layer (e.g., metal oxide layer 35) (not shown) as described herein including a plurality of features (e.g., features 45) (not shown) as described herein on first surface 32 of current collector 30. The oxygen and/or air may be provided by an oxygen source 40, such as compressed oxygen (O) gas, for example, 40₂) A container or a bottle.

In any embodiment, the current collector 30 may be placed at the focal plane of the laser beam 15. The laser beam 15 may be a nanosecond pulsed laser beam or an ultrafast laser beam, such as a picosecond laser, a femtosecond laser. The laser beam 15 may have a pulse width greater than or equal to about 1 ns and less than or equal to about 1 μ s, optionally greater than or equal to about 50 ns and less than or equal to about 500 ns, optionally greater than or equal to about 100 ns and less than or equal to about 250 ns, and optionally about 200 ns. The laser beam 15 may have a pulse overlap (pulse overlap) of greater than or equal to about 0% and less than or equal to about 90%, optionally greater than or equal to about 5% and less than or equal to about 75%, optionally greater than or equal to about 10% and less than or equal to about 50%, and optionally about 30%. The laser beam 15 may have a repetition rate (repetition rate) of greater than or equal to about 1 kHz and less than or equal to about 1 MHz, optionally greater than or equal to about 10 kHz and less than or equal to about 750 kHz, optionally greater than or equal to about 100 kHz and less than or equal to about 500 kHz, and optionally about 20 kHz.

The laser beam 15 may produce spot sizes greater than or equal to about 20 μm and less than or equal to about 1000 μm, optionally greater than or equal to about 40 μm and less than or equal to about 500 μm, optionally greater than or equal to about 60 μm and less than or equal to about 100 μm. The laser beam 15 may have a scan speed of greater than or equal to about 1 mm/s and less than or equal to about 15 m/s, optionally greater than or equal to about 100 mm/s and less than or equal to about 10 m/s, optionally greater than or equal to about 500 mm/s and less than or equal to about 5 m/s, and optionally greater than or equal to about 750 mm/s and less than or equal to about 1 m/s. The laser beam 15 may have a scan power of greater than or equal to about 50W and less than or equal to about 2000W, optionally greater than or equal to about 100W and less than or equal to about 1000W, optionally greater than or equal to about 200W and less than or equal to about 500W, and optionally greater than or equal to about 200W and less than or equal to about 400W.

In any embodiment, directing the laser beam 15 toward the first surface 32 of the current collector 30 produces a metal oxide layer as described herein that includes a plurality of features as described herein. For example, if the current collector comprises copper metal, the metal oxide layer formed on the first surface of the current collector is a copper oxide layer having a plurality of features. Similarly, if the current collector comprises nickel, the metal oxide layer formed on the first surface of the current collector is a nickel oxide layer having a plurality of features. The laser beam 15 may be moved relative to the current collector 30 as indicated by the arrows in fig. 3 to create a pattern, such as the various features described herein. For example, the laser head 20 may move the laser beam 15 while the current collector 30 remains stationary. In another example, the current collector 30 may be moved while the laser head 20 remains stationary.

The method further includes applying a lithium-containing layer described herein (e.g., lithium-containing layer 50) on the exposed surface of the metal oxide layer on the current collector such that the lithium-containing layer forms a bond with the first surface of the current collector as described herein. In certain aspects, applying the lithium-containing layer onto the exposed surface of the metal oxide layer comprises contacting the lithium-containing layer with the surface of the metal oxide layer using a linking method selected from the group consisting of: lamination, thermal bonding, hot dipping, spot welding, laser welding, ultrasonic welding, and combinations thereof.

In various aspects, the lithium-containing layer may be cleaned prior to being applied to or disposed on the current collector. Lithium metal is a relatively soft metal and is highly reactive. Thus, grit blasting the electrode with loose hard abrasives may not be suitable for cleaning the lithium-containing layer. Furthermore, in view of the high reactivity of lithium metal, it may also be suitable to avoid the use of protic solvents (e.g. alcohols, acetone, ethers, etc.) during cleaning. Thus, a suitable cleaning process may include wiping the lithium metal layer with an aprotic solvent (e.g., hexane), or other relatively mild cleaning techniques that do not undesirably react with the lithium metal.

In various aspects, applying the lithium-containing layer can include applying heat to the lithium-containing layer, the metal oxide layer, or both. The heat may be applied to the lithium containing layer before the lithium containing layer is applied to the metal oxide layer, while the lithium containing layer is applied to the metal oxide layer, after the lithium containing layer is applied to the metal oxide layer, or any combination thereof. Heating can result in the formation of a bonding layer (e.g., bonding layer 37) as described herein, wherein the bonding layer chemically bonds the lithium-containing layer to the metal oxide layer and the current collector, for example, by a reaction shown below:

MO + 2Li –> LiO₂ + M

wherein M represents a metal in the metal oxide layer. For example, if the metal oxide layer is a copper oxide layer, the bonding layer may comprise lithium oxide and copper. Thus, the heat may promote adhesion between the lithium-containing layer and the current collector. While suitable heating temperatures and conditions depend on the materials used, in various instances, the heat applied may be from about 100 ℃ to about 300 ℃, and in certain aspects optionally from about 140 ℃ to about 180 ℃. The heat may be applied for a period of time from about 1 minute to about 15 minutes.

In certain aspects, the method may further comprise applying pressure to the lithium-containing layer, the bonding layer, the metal oxide layer, and/or the current collector. The applied pressure may press the layers together and aid in the bonding and/or adhesion of the current collector and the lithium-containing layer. In various instances, pressure may be applied using rollers, platens, blades, and/or related methods. The applied pressure can be from about 0.1 MPa to about 5 MPa, and in certain aspects optionally from about 0.1 MPa to about 1 MPa. The pressure may be applied for a period of about 1 minute to about 15 minutes, and in certain aspects optionally about 1 minute to about 10 minutes. In certain aspects, the heat and pressure may be applied simultaneously.

In various aspects, one or more method steps may be performed in an inert environment (e.g., argon (Ar)) and/or vacuum. For example, the application or disposition of the lithium-containing layer onto the metal oxide layer disposed on the current collector and/or the heating of the lithium-containing layer, the metal oxide layer, and/or the current collector may be performed in an inert environment and/or in a vacuum to eliminate or minimize lithium metal side reactions.

As shown in fig. 4, the methods described herein may be incorporated into a continuous process for producing a large number of electrode assemblies. For example, the roll-to-roll process may be performed by moving the current collector sheet 31 on the roller system 65 under the laser head 20 connected to the gantry system 60. The laser head 20 may be moved in the direction indicated by the arrow to create a pattern of metal oxide layers 35 comprising a plurality of features as described herein on the first surface 32 of the current collector sheet 31.

Examples

Example 1-comparison of laser treated surface of copper (Cu) current collector to untreated surface of Cu current collector

In the presence of oxygen (e.g. from compressed O)₂Bottle), laser treating a portion of a surface of a Cu current collector with a nanosecond laser to form a CuO layer on the surface. The laser beam has a power of 270W, a wavelength of 1064 nm, a scanning speed of 500 mm/s, a pulse width of 200 ns, a repetition rate of 20 kHz, an overlap of 30% and a circular spot size of about 67 μm. The laser treatment temperature was about 3500 ℃. The remaining portion of the Cu current collector was not laser treated. A Scanning Electron Microscope (SEM) image of the Cu current collector was taken and as shown in fig. 5A, the untreated portion 500 of the Cu current collector had a smooth surface and the laser treated portion 510 of the Cu current collector included a number of features. The various features are more clearly depicted in fig. 5B, which shows an enlarged view of fig. 5A. X-ray photoelectron spectroscopy (XPS) analysis was performed on the untreated portion 500 and the laser treated portion 510 to determine the amount of oxygen. XPS results are shown in FIG. 6A, line605 corresponds to the untreated portion and line 607 corresponds to the laser treated portion. The x-axis in fig. 6A corresponds to the etching time (seconds) 601, and the y-axis corresponds to the atomic percent (%) 603. XPS analysis was also performed on the untreated portion 500 and the laser treated portion 510. XPS results of the untreated portion 500 and the laser treated portion 510 are shown in fig. 6B and 6C, respectively. The x-axis in fig. 6B and 6C corresponds to binding energy (eV)610 and the y-axis corresponds to counts/sec 612. FIG. 6C confirms the presence of CuO on the surface of the laser-treated portion 510, with regions 618 and 620 indicating the presence of strong Cu from CuO^{2 +}. FIG. 6B confirms that there is no or little CuO on the surface of the untreated portion 500, and the regions 614 and 616 indicate the absence of Cu²⁺。

Example 2 Peel-off test

Peel tests were performed on conventional lithium-based electrode assemblies and lithium-based electrode assemblies prepared according to the present disclosure. In particular, the conventional lithium-based electrode assembly is prepared by applying a lithium layer onto a Cu current collector, wherein the Cu current collector is untreated. A lithium-based electrode assembly prepared according to the present disclosure was prepared by laser treating a Cu current collector surface as described in example 1 above to form a CuO layer and applying a lithium foil layer onto the laser treated surface of the Cu current collector. As shown in fig. 7A, the lithium-based electrode assembly prepared according to the present disclosure showed excellent adhesion, while as shown in fig. 7B, the conventional lithium-based electrode assembly suffered adhesion failure.

The foregoing description of the embodiments has been presented 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 embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not explicitly shown or described. It can 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.

The present application may include the following technical solutions.

1. A method of manufacturing an electrode assembly for an electrochemical cell, the method comprising:

directing a laser beam in the presence of oxygen toward a first surface of a current collector comprising a metal to form a metal oxide layer on the first surface, wherein the metal oxide layer comprises a plurality of features; and

applying a lithium-containing layer onto the metal oxide layer, wherein the lithium-containing layer forms a bond with the first surface of the current collector.

2. The process of scheme 1, wherein the metal is selected from the group consisting of copper, nickel, titanium, iron, molybdenum, chromium, and combinations thereof, and the metal oxide is selected from the group consisting of copper oxide, nickel oxide, titanium oxide, iron oxide, molybdenum oxide, chromium oxide, and combinations thereof.

3. The method of protocol 1, wherein the laser beam has a power of greater than or equal to about 50W, a scan speed of greater than or equal to about 1 mm/s, and a spot size of greater than or equal to about 20 μm.

4. The method of scheme 1, wherein directing a laser beam toward a first surface of a current collector comprises moving a laser beam relative to the current collector to create the plurality of features on the first surface.

5. The method of scheme 1, wherein the binding is mechanical binding, chemical binding, or a combination thereof.

6. The method of scheme 1, wherein the plurality of features is a plurality of mechanical interlocking features that form a mechanical bond with the lithium-containing layer.

7. The method of scheme 1, wherein heat is applied to the lithium containing layer before the lithium containing layer is applied to the metal oxide layer, while the lithium containing layer is applied to the metal oxide layer, after the lithium containing layer is applied to the metal oxide layer, or a combination thereof.

8. The method of scheme 1, wherein a bonding layer is formed between a lithium-containing layer and a metal oxide layer, wherein the bonding layer chemically bonds the lithium-containing layer to the metal oxide layer, wherein the bonding layer comprises a lithium oxide, the metal, or a combination thereof.

9. The method of scheme 1, wherein the lithium-containing layer is a lithium foil or a lithium film.

10. An electrode assembly for an electrochemical cell, comprising:

a current collector having a first surface, wherein the current collector comprises a metal;

a metal oxide layer disposed on the first surface of the current collector, wherein the metal oxide layer comprises a plurality of features; and

a lithium-containing layer bonded to the first surface of the current collector.

11. The electrode assembly of scheme 10, wherein the metal is selected from the group consisting of copper, nickel, titanium, iron, molybdenum, chromium, and combinations thereof, and the metal oxide is selected from the group consisting of copper oxide, nickel oxide, titanium oxide, iron oxide, molybdenum oxide, chromium oxide, and combinations thereof.

12. The electrode assembly of scheme 10, wherein the bonding is mechanical bonding, chemical bonding, or a combination thereof.

13. The electrode assembly of scheme 10, wherein the plurality of features is a plurality of mechanical interlocking features that form a mechanical bond with the lithium-containing layer.

14. The electrode assembly of scheme 10, further comprising a bonding layer disposed between the lithium-containing layer and the metal oxide layer, wherein the bonding layer chemically bonds the lithium-containing layer to the metal oxide layer, wherein the bonding layer comprises lithium oxide, the metal, or a combination thereof.

15. The electrode assembly of scheme 10, wherein the lithium-containing layer is a lithium foil or a lithium film.

16. A lithium-containing electrochemical cell comprising:

a negative electrode assembly, comprising:

a current collector having a first surface, wherein the current collector comprises a metal;

a metal oxide layer disposed on the first surface of the current collector, wherein the metal oxide layer comprises a plurality of features; and

a lithium-containing layer bonded to the first surface of the current collector;

a positive electrode assembly spaced apart from the negative electrode assembly;

a porous separator disposed between opposing surfaces of the negative electrode assembly and the positive electrode assembly; and

a liquid electrolyte infiltrating the negative electrode assembly, the positive electrode assembly, and the porous separator.

17. The lithium-containing electrochemical cell of claim 16, wherein the metal is selected from the group consisting of copper, nickel, titanium, iron, molybdenum, chromium, and combinations thereof, the metal oxide is selected from the group consisting of copper oxide, nickel oxide, titanium oxide, iron oxide, molybdenum oxide, chromium oxide, and combinations thereof, and the lithium-containing layer is a lithium foil or a lithium film.

18. The lithium-containing electrochemical cell of scheme 16, wherein the bonding is mechanical bonding, chemical bonding, or a combination thereof.

19. The lithium-containing electrochemical cell of claim 16, wherein the plurality of features are a plurality of mechanical interlocking features that form a mechanical bond with the lithium-containing layer.

20. The lithium-containing electrochemical cell of claim 16, wherein the negative electrode assembly further comprises a bonding layer disposed between the lithium-containing layer and the metal oxide layer, wherein the bonding layer chemically bonds the lithium-containing layer to the metal oxide layer, wherein the bonding layer comprises lithium oxide, the metal, or a combination thereof.