CN117157196A

CN117157196A - Biodegradable electrochemical device with barrier layer

Info

Publication number: CN117157196A
Application number: CN202280026314.1A
Authority: CN
Inventors: G·麦圭尔; N·乔普拉; N-X·胡; A·拉福格; N·沙普洛
Original assignee: National Research Council of Canada; Xerox Corp
Current assignee: National Research Council of Canada; Xerox Corp
Priority date: 2021-03-31
Filing date: 2022-03-30
Publication date: 2023-12-01
Also published as: EP4313591A1; CA3213871A1; JP2024512955A; WO2022212454A1

Abstract

An electrochemical device is disclosed that may include an electrolyte composition disposed between an anode and a cathode and a water vapor barrier that may include a biodegradable material, wherein the water vapor barrier is configured to prevent water vapor from escaping from the electrochemical device. The water vapor barrier may also include polylactic acid or a metallized coating. The water vapor barrier may further comprise a plurality of layers and has a Water Vapor Transmission Rate (WVTR) of less than or equal to 2 wt% over 24 hours. Embodiments of the water vapor barrier may also include a polymeric biodegradable material or a metallized coating disposed on the biodegradable material. The water vapor barrier may further comprise a plurality of layers and has a Water Vapor Transmission Rate (WVTR) of less than or equal to 1mg/cm over a 24 hour period ² 。

Description

Biodegradable electrochemical device with barrier layer

Technical Field

Embodiments or embodiments of the present disclosure relate to biodegradable electrochemical devices, solid aqueous electrolytes thereof, and moisture barriers therefor.

Background

As the demand for portable and remote power sources continues to increase, the number of batteries produced in the world continues to increase. In particular, many new technologies require batteries to power embedded electronic devices. For example, embedded electronics, such as portable and wearable electronics, internet of things (IoT) devices, patient health monitoring, structural monitoring, environmental monitoring, smart packaging, and the like, all rely on battery power. Although the conventional battery can be partially recycled, no environment-friendly or biodegradable battery is currently available on the market. Thus, if not properly disposed or recycled, the increase in traditional battery manufacturing and use can result in a corresponding increase in toxic and hazardous waste in the environment. In view of this, there is a need to develop biodegradable batteries; particularly for those applications where disposable batteries are used for a limited period of time before disposal.

In addition, to meet the demand for flexible, low cost, medium or low performance batteries, all-printed batteries have been developed, which are marketed as single-use disposable batteries. However, none of these all-printed batteries are biodegradable.

One of the biggest challenges in producing biodegradable batteries is generally considered to be the development of biodegradable polymer electrolytes, which are the major polymer-based components of all-printed batteries. Moreover, developing a biodegradable polymer electrolyte that can also be printed using existing printing techniques is also an additional challenge.

Conventional biodegradable polymer electrolytes can generally include a combination of a biodegradable polymer and a conductive salt. To obtain a biodegradable polymer electrolyte, a biodegradable polymer and a conductive salt are dissolved in a solvent, and then the solvent is evaporated at a relatively slow rate to produce a solid polymer electrolyte membrane. Due to the low ion mobility in biodegradable polymers, these conventional biodegradable polymer electrolytes typically have low ionic conductivity at ambient temperature (e.g., less than about 10 at RT ^-5 S/cm). However, sufficient conductivity can be achieved if the polymer electrolyte is heated to a temperature (i.e., an operating temperature) sufficient to allow movement of the polymer chains, thereby allowing the ions to move more freely in the polymer electrolyte structure. Sufficient conductivity can also be achieved by adding additives to inhibit the crystallinity of the polymer electrolyte, thereby lowering its operating temperature. Therefore, biodegradable polymer electrolytes that can operate at room temperature with sufficient conductivity are limited.

In addition to the above drawbacks, the conventional biodegradable polymer electrolyte has a problem in that the manufacturing process is lengthy due to the time required for evaporating the solvent during the manufacturing process. For example, vacuum and/or temperature assisted evaporation of several hours is typically required to evaporate the solvent to produce a conventional biodegradable polymer electrolyte, and therefore, compatibility of the conventional biodegradable polymer electrolyte with high throughput printing processes in which successive layers must be laminated together within several minutes is restricted.

Although printable, biodegradable electrochemical devices, solid aqueous electrolytes thereof, and methods of synthesizing and manufacturing thereof exist, layers of various materials, including current collectors, cathode/anode materials, binders, adhesives, and electrolytes, require high fidelity, high precision printing. In addition, the maintenance of moisture or water content in an aqueous electrolyte is critical to battery performance by maintaining dissolved salts to achieve good ionic conductivity, while printed biodegradable batteries can suffer from reduced life due to loss of moisture by evaporation through biodegradable substrates such as polylactic acid (PLA) films. It is desirable to increase the moisture retention of these cells, particularly the electrolyte layer, by reducing the WVTR (water vapor transmission rate). At the same time, it remains a challenge to achieve sealing performance around an electrochemical device while maintaining or reducing the non-biodegradable content of printed biodegradable batteries, and sealing printed batteries (e.g., lithium ion batteries) is currently not possible using conventional relatively thick non-biodegradable foil "pouches".

Disclosure of Invention

The following is a simplified summary in order to provide a basic understanding of some aspects of one or more embodiments of the present teachings. This summary is not an extensive overview nor is it intended to identify key or critical elements of the teachings nor is it intended to delineate the scope of the disclosure. Rather, its primary purpose is merely to present one or more concepts in a simplified form as a prelude to the more detailed description that is presented later.

An electrochemical device is disclosed. The electrochemical device further includes an anode and a cathode. The device further includes an electrolyte composition disposed between the cathode and the anode, and a water vapor barrier, which may include a biodegradable material, wherein the water vapor barrier is configured to prevent water vapor from escaping from the electrochemical device. The water vapor barrier may also include polylactic acid. The water vapor barrier may also include a metallized or aluminum metallized coating. The water vapor barrier may further comprise a plurality of layers. The electrochemical device may also have a Water Vapor Transmission Rate (WVTR) of less than or equal to 2 wt% over 24 hours.

Embodiments of the water vapor barrier may also include a biodegradable material, which may include a polymer. The water vapor barrier may also include a metallized coating disposed on the biodegradable material. The water vapor barrier may include a polymer (which may further Including polylactic acid), metallized or aluminum metallized coatings. The water vapor barrier may also include a plurality of layers, and may have a Water Vapor Transmission Rate (WVTR) of less than or equal to 1mg/cm over a 24 hour period ² 。

Brief description of the drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present teachings. These and/or other aspects and advantages in embodiments of the disclosure will be apparent from and more readily appreciated from the following description of the various embodiments, taken in conjunction with the accompanying drawings, of which:

fig. 1 shows an exploded view of an exemplary biodegradable electrochemical device in a side-by-side configuration in accordance with one or more embodiments disclosed.

Fig. 2 illustrates an exploded view of another exemplary biodegradable electrochemical device in accordance with a stacked configuration of one or more embodiments disclosed.

Fig. 3 illustrates a cross-sectional view of a comparative example of a fully assembled surrogate of a biodegradable battery assembly having a water vapor barrier according to one or more embodiments.

Fig. 4 illustrates a cross-sectional view of an embodiment of a fully assembled surrogate of the electrochemical device assembly of example 1 having a water vapor barrier according to one or more embodiments.

Fig. 5 illustrates a cross-sectional view of an embodiment of a fully assembled surrogate of the electrochemical device assembly of example 2 having a water vapor barrier according to one or more embodiments.

Fig. 6 illustrates a cross-sectional view of an embodiment of a fully assembled surrogate of the electrochemical device assembly of example 3, having a water vapor barrier according to one or more embodiments.

Fig. 7 illustrates a cross-sectional view of one example of a surrogate for an electrochemical device assembly having a multi-layered encapsulated structure according to the present disclosure.

Fig. 8 shows a plot of water loss in milligrams per square centimeter versus time in days for the comparative example of fig. 3 as compared to examples 1-5 of fig. 4, 5, 6, and 7, respectively.

It should be noted that certain details in the figures have been simplified and that these details are drawn to facilitate the understanding of the present teachings, rather than to maintain strict structural accuracy, detail and scale.

Detailed Description

The following description of various exemplary aspects is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses.

As used throughout, ranges are used as shorthand expressions for describing each and every value that is within the range. Any value within the range can be selected as the end of the range. In addition, all references cited herein are incorporated by reference in their entirety. If a definition in the present disclosure conflicts with a definition in a cited reference, the present disclosure controls.

All percentages and amounts expressed herein and elsewhere in the specification are to be understood as weight percent unless otherwise indicated. The amounts given are based on the effective weight (active weight) of the material.

In addition, all numbers are either "about" or "approximately" as indicated, and experimental errors and variations as would be expected by one of ordinary skill in the art are contemplated. It is to be understood that all numerical values and ranges disclosed herein are approximations and ranges, whether or not it is utilized in conjunction with the "about". It will also be understood that the term "about" as used herein in connection with a number means that the value may be + -0.01% (inclusive) of the number, + -0.1% (inclusive), + -0.5% (inclusive), + -1% (inclusive), + -2% (inclusive) of the number, + -3% (inclusive) of the number, + -5% (inclusive) of the number, + -10% (inclusive) of the number, or + -15% (inclusive) of the number. It is further understood that when a range of values is disclosed herein, that is, any value within the range is specifically disclosed.

As used herein, the term "or" is an inclusive operator, equivalent to the term "and/or," unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for being based on other factors not described, unless the context clearly dictates otherwise. In the specification, the description of "at least one of A, B and C" includes embodiments comprising a combination of A, B or C, A, B or C, or A/B, A/C, B/C, A/B/B/B/B/C, A/B/C, etc. Furthermore, throughout the specification, the meaning of "a", "an", and "the" includes plural. The meaning of "in … … (in)" includes "in … … (in)" and "on … … (on)".

Reference will now be made in detail to exemplary embodiments of the present teachings, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same, like or like parts.

Disclosed herein is a biodegradable electrochemical device. As used herein, the term "biodegradable" or "biodegradable material" may refer to materials, components, substances, devices, etc. that are capable of or configured to be decomposed by organisms, particularly microorganisms in a landfill, in a reasonable time. Materials, components, substances, devices, etc. may be decomposed into water, carbon dioxide, methane, etc. naturally occurring gases, biomass, or combinations thereof. As used herein, the expression "biodegradable electrochemical device" or "biodegradable device" may refer to such electrochemical device or device, respectively: wherein at least one or more components thereof are biodegradable. In some cases, the biodegradable device or a substantial portion or number of components of the biodegradable device are biodegradable. In other cases, the biodegradable electrochemical device or all of the polymeric components of the biodegradable device are biodegradable. For example, the polymers and/or other organic-based components in the biodegradable devices are biodegradable, while the inorganic materials, including metals and/or metal oxides, in the biodegradable devices disclosed herein may not be biodegradable. It should be understood that an entire electrochemical device is generally considered to be biodegradable if all of the polymeric and/or organic based components of the electrochemical device are biodegradable. As used herein, the term "compostable" may refer to an article that can be composted or disposed of in a sustainable or environmentally friendly manner. The compostable materials may be considered a subset class of biodegradable materials in which additional specific ambient temperatures or conditions may be required to break down the compostable materials. Although the terms compostable and biodegradable are not synonymous, they may be used interchangeably in some cases, where the conditions required to decompose or decay biodegradable materials are understood to be similar to the conditions required to decompose compostable materials. As used herein, the term or expression "electrochemical device" may refer to a device that converts electricity into a chemical reaction and/or converts a chemical reaction into electricity. Exemplary electrochemical devices may be or include, but are not limited to, batteries, dye sensitized solar cells, electrochemical sensors, electrochromic glasses, fuel cells, electrolyzers, and the like.

As used herein, the term or expression "environmentally friendly electrochemical device" or "environmentally friendly device" may refer to an electrochemical device or device, respectively, that has substantially minimal, reduced, or no toxicity to the ecosystem or environment. In at least one embodiment, the electrochemical devices and/or components thereof disclosed herein are environmentally friendly.

As used herein, the term or expression "film" or "barrier layer" may refer to a thin, partial or substantially plastic and/or polymeric material that may be used in various electrochemical device components or parts, including, but not limited to, substrates, connectors, encapsulants (enclosures), barriers, or combinations thereof. The films described herein may be rigid or flexible depending on the inherent physical properties or dimensions of their respective compositions. In at least one embodiment, these films or barrier layers may be environmentally friendly or biodegradable.

As used herein, the terms or expressions "enclosure," "barrier," or "water vapor barrier" may refer to a material that is partially sealed, fully sealed, or otherwise used to prevent ingress or egress of moisture, water, or other vaporizable material through a barrier of an electrochemical device. In at least one embodiment, these encapsulates may be environmentally friendly or biodegradable.

As used herein, the term or expression "metal layer" may refer to a layer of metal on a surface, film, substrate, or barrier layer. Examples of metal layers described herein may include: a metallized coating that may be deposited onto a surface by vapor or chemical deposition, as well as a metal layer including a metal foil, a metal film, or other metal layer that is combined with or adhered to a surface, film, substrate, or barrier layer.

In at least one embodiment, the biodegradable electrochemical devices disclosed herein can include an anode, a cathode (i.e., a current collector and/or an active layer), and one or more electrolyte compositions (e.g., a biodegradable solid aqueous electrolyte composition). In another embodiment, the biodegradable electrochemical device may further comprise one or more substrates, one or more seals, one or more packages, one or more bags, one or more envelopes, or a combination thereof.

The biodegradable electrochemical devices disclosed herein may be flexible. As used herein, the term "flexible" may refer to a material, device, or component thereof that can bend around a predetermined radius of curvature without breaking and/or cracking. The biodegradable electrochemical devices and/or components thereof disclosed herein can be bent about a radius of curvature of about 30 cm or less, about 20 cm or less, about 10 cm or less, about 5 cm or less without breaking or cracking.

Fig. 1 illustrates an exploded view of an exemplary biodegradable electrochemical device 100 in a side-by-side or co-planar configuration, according to one or more embodiments. As shown in fig. 1, the biodegradable electrochemical device 100 may include: a first substrate 102, first and second current collectors 104, 106 adjacent to or on top of the first substrate 102, an anode active layer 108 adjacent to or on top of the first current collector 104, a cathode active layer 110 adjacent to or on top of the second current collector 106, an electrolyte layer 112 adjacent to or on top of the anode active layer 108 and the cathode active layer 110, and a second substrate 114 adjacent to or on top of the electrolyte composition 112. It should be understood that the first current collector 104 and the anode active layer 108 may be collectively referred to herein as an anode 120 of the biodegradable electrochemical device 100. It should also be appreciated that the second current collector 106 and the cathode active layer 110 may be collectively referred to herein as the cathode 122 of the biodegradable electrochemical device 100. As shown in fig. 1, the anode 120 and the cathode 122 of the biodegradable electrochemical device 100 may be coplanar such that the anode 120 and the cathode 122 are arranged along the same X-Y plane.

In at least one embodiment, the biodegradable electrochemical device 100 can include one or more seals (two seals are shown as 116, 118) that are capable of or configured to seal or hermetically seal the current collectors 104, 106, the anode active layer 108, the cathode active layer 110, and the electrolyte composition 112 between the first and second substrates 102, 114 of the biodegradable electrochemical device 100. For example, as shown in fig. 1, the biodegradable electric device 100 may include two sealing members 116, 118 interposed between the first and second substrates 102, 114 and surrounding the current collectors 104, 106, the anode active layer 108, the cathode active layer 110, and the electrolyte composition 112 to seal or hermetically seal the biodegradable electrochemical device 100. In another embodiment, the biodegradable electrochemical device 100 may be free or substantially free of the seals 116, 118. For example, the substrates 102, 114 may be fused or bonded to each other to seal the biodegradable electrochemical device 100.

Fig. 2 illustrates an exploded view of another example biodegradable electrochemical device 200 in a stacked configuration in accordance with one or more embodiments. As shown in fig. 2, the biodegradable electrochemical device 200 may include: a first substrate 202, a first current collector 204 adjacent to or on top of the first substrate 202, an anode active layer 208 adjacent to or on top of the first current collector 204, an electrolyte layer 212 adjacent to or on top of the anode active layer 208, a cathode active layer 210 adjacent to or on top of the electrolyte composition 212, a second current collector 206 adjacent to or on top of the cathode active layer 210, and a second substrate 214 adjacent to or on top of the second current collector 206. It should be understood that the first current collector 204 and the anode active layer 208 may be collectively referred to herein as an anode 220 of the biodegradable electrochemical device 200. It should also be appreciated that the second current collector 206 and the cathode active layer 210 may be collectively referred to herein as the cathode 222 of the biodegradable electrochemical device 200. As shown in fig. 2, the anode 220 and the cathode 222 of the biodegradable electrochemical device 200 may be arranged in a stacked configuration or geometry such that the anode 220 and the cathode 222 are disposed above or below each other.

In at least one embodiment, the biodegradable electrochemical device 200 can include one or more seals (two seals are shown as 216, 218) that are capable of or configured to hermetically seal the current collectors 204, 206, the anode active layer 208, the cathode active layer 210, and the electrolyte composition 212 between the first and second substrates 202, 214 of the biodegradable electrochemical device 200. For example, as shown in fig. 2, the biodegradable electric device 200 may include two seals 216, 218 interposed between the first and second substrates 202, 214 and surrounding the current collectors 204, 206, the anode active layer 208, the cathode active layer 210, and the electrolyte composition 212 to hermetically seal the biodegradable electrochemical device 200. In another embodiment, the biodegradable electrochemical device 200 may be free or substantially free of the seals 216, 218. For example, the substrates 202, 214 may be fused or bonded to each other to seal the biodegradable electrochemical device 200.

As shown in fig. 1 and 2, each current collector 104, 106, 204, 206 may include a respective tab (tab) 124, 126, 224, 226 that may extend outside of the seal 116, 118, 216, 218 to provide connectivity.

In at least one embodiment, any one or more of the substrates 102, 114, 202, 214 of each biodegradable electrochemical device 100, 200 may be or include (but are not limited to) a biodegradable substrate. Exemplary biodegradable substrates may be or include, but are not limited to, one or more of polylactic acid (PLA), polylactic-co-glycolic acid (PLGA), silk-fibroin (silk-fibrin), chitosan, polycaprolactone (PCL), polyhydroxybutyrate (PHB), rice paper, cellulose, or combinations or composites thereof.

The biodegradable substrate of each biodegradable electrochemical device 100, 200 may remain stable at a temperature of about 50 ℃ to about 150 ℃. As used herein, the term "stable" or "stability" may refer to the ability of a substrate to resist dimensional changes and maintain structural integrity when exposed to temperatures from about 50 ℃ to about 150 ℃. For example, the biodegradable substrate can or is configured to maintain structural integrity after exposure to a temperature of about 50 ℃ to about 150 ℃, with a dimensional change of less than about 20%, less than about 15%, or less than about 10%. In one example, each biodegradable substrate can be stable (e.g., less than 20% change in size) at a temperature of from about 50 ℃, about 60 ℃, about 70 ℃, about 80 ℃, about 90 ℃, about 100 ℃, or about 110 ℃ to about 120 ℃, about 130 ℃, about 140 ℃, or about 150 ℃. In another example, each biodegradable substrate can be stable at a temperature of at least 100 ℃, at least 105 ℃, at least 110 ℃, at least 115 ℃, at least 120 ℃, at least 125 ℃, at least 130 ℃, at least 135 ℃, at least 140 ℃, or at least 145 ℃. In at least one embodiment, the biodegradable substrate may be stable at a temperature of about 50 ℃ to about 150 ℃ for about 5 minutes to about 60 minutes or more. For example, the biodegradable substrate may be stable at the above temperatures for about 5 minutes, about 10 minutes, about 20 minutes, or about 30 minutes to about 40 minutes, about 45 minutes, about 50 minutes, about 60 minutes, or more.

In at least one embodiment, the biodegradable substrate is weldable, bondable, and/or permanently heat sealable without the use of additional adhesives. For example, the biodegradable substrates of the substrates 102, 114, 202, 214 may all be welded and/or bonded to one another without the use of the respective seals 116, 118, 216, 218. Exemplary biodegradable substrates that can be welded and/or bonded to each other can be or include, but are not limited to, thermoplastics such as polylactic acid (PLA), polylactides modified with a nucleating agent to increase crystallinity (e.g., polylactides modified with a nucleating agent D (PLA-D) and polylactides modified with a nucleating agent E (PLA-E)), polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), PLA and Polyhydroxybutyrate (PHB) blends, PHB-based blends, and the like, or combinations thereof. As used herein, the terms or expressions "bondable," "weldable," and/or "permanently heat sealable" may refer to the ability of a material (e.g., a substrate) to heat seal two surfaces to one another or to permanently join two surfaces to one another by heating or melting.

The anode active layer 108, 208 of each biodegradable electrochemical device 100, 200 may be or include (but is not limited to) ) Zinc (Zn), lithium (Li), carbon (C), cadmium (Cd), nickel (Ni), magnesium (Mg), magnesium alloys, zinc alloys, and the like, or combinations and/or alloys thereof. Exemplary anode active layers or materials thereof may be or include (but are not limited to), the like, or combinations thereof. In at least one embodiment, the anode active layer may include a sufficient amount of zinc oxide (ZnO) to regulate or control H ₂ And (3) gas.

In at least one embodiment, the anode active layer 108, 208 of each biodegradable electrochemical device 100, 200 may be prepared or fabricated from an anode paste. For example, the anode active layer may be prepared from zinc anode paste. The anode paste may be prepared in an attritor mill. In at least one embodiment, the stainless steel shot may be placed in a stirred ball mill to facilitate the preparation of the anode paste. The anode paste may include one or more metals or metal alloys, one or more organic solvents, one or more styrene-butadiene rubber binders, or combinations thereof. In exemplary embodiments, the anode paste may include ethylene glycol, a styrene-butadiene rubber binder, zinc oxide (ZnO), bismuth (III) oxide (Bi ₂ O ₃ ) One or more of zinc powder, or a combination thereof. Exemplary organic solvents are known in the art and may be or include (but are not limited to) ethylene glycol, acetone, NMP, and the like, or combinations thereof. In at least one embodiment, any one or more biodegradable binders may be used in place of, or in combination with, the styrene butadiene rubber binder.

The cathode active layer 110, 210 of each biodegradable electrochemical device 100, 200 may be or include (but is not limited to): iron (Fe), iron (VI) oxide, mercury oxide (HgO), manganese (IV) oxide, carbon (C), carbon-containing cathode, gold (Au), molybdenum (Mo), tungsten (W), molybdenum trioxide (MoO) ₃ ) Silver oxide (Ag) ₂ O), copper (Cu), vanadium oxide (V) ₂ O ₅ ) Nickel oxide (NiO), copper iodide (Cu) ₂ I ₂ ) Copper chloride (CuCl), etc., or combinations and/or alloys thereof. In one exemplary embodiment, the cathode active layer 110, 210 may include manganese (IV) oxide. Carbon and/or carbon-containing cathode active layers can be used in aqueous metal-air batteries, such as zinc-air batteries.

In at least one embodiment, the cathode active layer 110, 210 may include one or more additives capable of or configured to at least partially enhance the electron conductivity of the cathode active layer 110, 210. Exemplary additives may be or include, but are not limited to, carbon particles such as graphite, carbon nanotubes, carbon black, and the like, or combinations thereof.

In at least one embodiment, the cathode active layer 110, 210 of each biodegradable electrochemical device 100, 200 may be prepared or manufactured from a cathode paste. For example, the cathode active layer 110, 210 may be prepared from a manganese (IV) oxide cathode paste. The cathode paste may be prepared in a stirred ball mill. In at least one embodiment, stainless steel shot may be placed in a stirred ball mill to facilitate the preparation of the cathode paste. The cathode paste may include one or more metals or metal alloys, one or more organic solvents (such as ethylene glycol), one or more styrene-butadiene rubber binders, or combinations thereof. In one exemplary embodiment, the cathode paste may include ethylene glycol, a styrene-butadiene rubber binder, manganese (IV) oxide (MnO ₂ ) One or more of graphite, or a combination thereof. Exemplary organic solvents are known in the art and may be or include (but are not limited to) ethylene glycol, acetone, NMP, and the like, or combinations thereof. In at least one embodiment, one or more organic solvents may be substituted with or used in combination with an aqueous solvent (e.g., water). For example, water may be used with manganese (IV) oxide.

The viscosity of the anode and/or cathode paste may be about 100cP to about 1e6 cP. For example, the viscosity of the anode and/or cathode paste may be greater than or equal to about 100cP, greater than or equal to about 200cP, greater than or equal to about 500cP, greater than or equal to about 1,000cP, greater than or equal to about 1,500cP, greater than or equal to about 2,000cP, greater than or equal to about 10,000cP, greater than or equal to about 20,000cP, greater than or equal to about 50,000cP, greater than or equal to about 1e5 cP, greater than or equal to about 1.5e5 cP, greater than or equal to about 2e5 cP, greater than or equal to about 3e5 cP, greater than or equal to about 4e5 cP, greater than or equal to about 5e5 cP, greater than or equal to about 6e5 cP, greater than or equal to about 7e5 cP, greater than or equal to about 8e5 cP, or greater than or equal to about 9e5 cP. In another embodiment, the viscosity of the anode and/or cathode paste may be less than or equal to about 200cP, less than or equal to about 500cP, less than or equal to about 1,000cP, less than or equal to about 1,500cP, less than or equal to about 2,000cP, less than or equal to about 10,000cP, less than or equal to about 20,000cP, less than or equal to about 50,000cP, less than or equal to about 1e5 cP, less than or equal to about 1.5e5 cP, less than or equal to about 2e5 cP, less than or equal to about 3e5 cP, less than or equal to about 4e5 cP, less than or equal to about 5e5 cP, less than or equal to about 6e5 cP, less than or equal to about 7e5 cP, less than or equal to about 8e5 cP, less than or equal to about 9e5 cP, or less than or equal to about 1e6 cP.

In at least one embodiment, each of the anode 120, 220 and cathode 122, 222 or active layers 108, 110, 208, 210 thereof may independently include a biodegradable binder. The function of the biodegradable binder is to secure the particles of each of the layers, either anode current collector 104, 204, cathode current collector 106, 206, anode active layer 108, 208, cathode active layer 110, 210, or a combination thereof, together and provide adhesion to the underlying substrate. Exemplary biodegradable binders may be or include, but are not limited to, one or more of chitosan, polylactic-co-glycolic acid (PLGA), gelatin, xanthan gum, cellulose Acetate Butyrate (CAB), polyhydroxybutyrate (PHB), or combinations thereof. In at least one embodiment, any one or more of the biodegradable polymers disclosed herein with respect to the electrolyte composition may also be used as the biodegradable binder for the anode 120, 220, cathode 122, 222, components thereof, or any combination thereof. As further described herein, the one or more biodegradable polymers may be crosslinked. Thus, the degradable biological binders for the anode 120, 220, cathode 122, 222, and/or components thereof may include crosslinked biodegradable binders disclosed herein for the electrolyte compositions.

The electrolyte layer 112, 212 of each of the respective biodegradable electrochemical devices 100, 200 may be or include an electrolyte composition. The electrolyte composition may utilize a biodegradable polymeric material. The electrolyte composition may be a solid aqueous electrolyte composition. The solid aqueous electrolyte composition may be or include a copolymer hydrogel and a salt dispersed in the hydrogel and/or throughout the hydrogel. The copolymer may include at least two Polycaprolactone (PCL) chains linked with a polymer Central Block (CB). For example, the copolymer may be a block copolymer or a graft copolymer comprising at least two PCL chains, such as PCL-CB-PCL, attached to a central block of the polymer. In another example, the copolymer may be a block copolymer or a graft copolymer comprising at least one or more of polylactic acid (PLA), polyglycolic acid (PGA), polyethylenimine (PEI), or a combination thereof, linked to a polymer central block.

The copolymer or solid may be present in the hydrogel in an amount of about 5 wt% or more to 90 wt% or less based on the total weight of the hydrogel (e.g., the total weight of solvent, polymer, and salt). For example, the copolymer may be present in an amount of about 5% by weight or greater, 10% by weight or greater, 15% by weight or greater, 20% by weight or greater, 25% by weight or greater, 30% by weight or greater, 35% by weight or greater, based on the total weight of the hydrogel. In another example, the copolymer may be present in an amount of 90 wt% or less, 80 wt% or less, 70 wt% or less, or 60 wt% or less based on the total weight of the hydrogel. In a preferred embodiment, the copolymer or solid may be present in the hydrogel in an amount of about 5 wt% to about 60 wt%, about 5 wt% to about 50 wt%, about 20 wt% to about 40 wt%, or about 30 wt%, based on the total weight of the hydrogel. In yet another preferred embodiment, the copolymer or solid may be present in the hydrogel in an amount of from greater than 30% to 60% by weight based on the total weight of the hydrogel.

The copolymer may be present in the hydrogel in an amount sufficient to provide a bubble-free or substantially bubble-free continuous film or layer. The copolymer may also be present in the hydrogel in an amount sufficient to provide a viscosity of about 1,000cp to about 100,000 cp. For example, the copolymer is present in the hydrogel in an amount sufficient to provide a viscosity of from about 1,000cp, about 5,000cp, about 10,000cp, or about 20,000cp to about 30,000cp, about 40,000cp, about 50,000cp, about 75,000cp, about 90,000cp, or about 100,000 cp.

The polymer core block of the copolymer may be a biodegradable polymer, thereby improving or increasing the biodegradability of the solid aqueous electrolyte composition. The biodegradable polymer of the polymer central block is preferably naturally occurring. The polymeric central block may be or include, or be derived from, a polymer, such as a biodegradable polymer, that includes at least two free hydroxyl groups that are reactive with epsilon-caprolactone. Also as described herein, a polymer comprising at least two free hydroxyl groups can be reacted with epsilon-caprolactone to form a copolymer. Exemplary polymers that include at least two free hydroxyl groups that can be used to form the polymeric Center Block (CB) can be or include, but are not limited to, one or more of polyvinyl alcohol (PVA), hydroxyl-containing polysaccharides, biodegradable polyesters, hydroxy fatty acids (such as castor oil), and the like, or combinations thereof. Exemplary hydroxyl-containing polysaccharides may be or include, but are not limited to, starch, cellulose, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, chitin, guar gum, xanthan gum, agar, pullulan, amylose (amylose), alginic acid, dextran, and the like, or combinations thereof. Exemplary degradable biopolyesters can be or include, but are not limited to, polylactide, polyglycolic acid, polylactide-co-glycolic acid, polyitaconic acid, polybutylene succinate, and the like, or combinations thereof. In preferred embodiments, the polymeric central block may be or include one or more of polyvinyl alcohol (PVA), hydroxyl containing polysaccharides, biodegradable polyesters, or hydroxy fatty acids.

In at least one embodiment, the polymer core block of the copolymer may not be a biodegradable polymer. For example, the polymeric central block of the copolymer may be or include, but is not limited to, polyethylene glycol (PEG), hydroxyl terminated polyesters, hydroxyl terminated polyolefins (e.g., hydroxyl terminated polybutadiene), and the like, or combinations thereof.

The copolymer comprising at least two Polycaprolactone (PCL) chains bonded to the polymer central block may be a graft copolymer or a block copolymer. Whether the polymer is a graft copolymer or a block polymer may depend, at least in part, on the number and/or location of the at least two free hydroxyl groups of the polymer center block. For example, epsilon caprolactone is reacted with a polymer center block having hydroxyl groups on monomers along the length of the polymer center block chain to form a graft copolymer. In another example, epsilon-caprolactone is reacted with a polymer center block having hydroxyl groups at each end of the polymer center block, respectively, to form a block copolymer. Exemplary block copolymers may be or include triblock copolymers, tetrablock copolymers, radial block copolymers, or combinations thereof.

As described above, the electrolyte composition may be a solid aqueous electrolyte composition including a hydrogel of the copolymer and a salt dispersed in the hydrogel. The salt in the hydrogel may be or include any suitable ionic salt known in the art. Exemplary ionic salts may be or include (but are not limited to) one or more of organic based salts, inorganic based salts, room temperature ionic liquids, deep eutectic solvent based salts, and the like, or combinations or mixtures thereof. In a preferred embodiment, the salt is or includes a salt useful for zinc/manganese (IV) oxide (Zn/MnO) ₂ ) Electrochemical salts. Exemplary salts may be or include, but are not limited to, zinc chloride (ZnCl) ₂ ) Ammonium chloride (NH) ₄ Cl), sodium chloride (NaCl), phosphate Buffered Saline (PBS), sodium sulfate (Na) ₂ SO ₄ ) Zinc sulfate (ZnSO) ₄ ) Manganese sulfate (MnSO) ₄ ) Magnesium chloride (MgCl) ₂ ) Calcium chloride (CaCl) ₂ ) Ferric chloride (FeCl) ₃ ) Lithium hexafluorophosphate (LiPF) ₆ ) Potassium hydroxide (KOH), sodium hydroxide (NaOH), and the like, or a combination thereof. In a preferred embodiment, the salt of the electrolyte composition may be or include ammonium chloride (NH ₄ Cl), zinc chloride (ZnCl) ₂ ) Or a combination or mixture thereof. In another embodiment, the salt may be or include an alkali metal salt, such as sodium hydroxide (NaOH), ammonium hydroxide (NH) ₄ OH), potassium hydroxide (KOH), or a combination or mixture thereof.

The salt may be present in an amount that is capable of, configured to, or sufficient to provide ionic conductivity. For example, the salt may be present in the hydrogel in an amount or concentration of at least 0.1M, more preferably at least 0.5M, even more preferably at least 2M, even more preferably at least 4M. The salt may be present in the hydrogel at a concentration of 10M or less, more preferably 6M or less. In another example, the salt may be present in the hydrogel in an amount of about 3M to about 10M, about 4M to about 10M, about 5M to about 9M, or about 6M to about 8M. In one exemplary embodiment, the salt includes ammonium chloride and zinc chloride, wherein the ammonium chloride is present in an amount of about 2.5M to about 3M, about 2.8M to about 2.9M, or about 2.89M, and the zinc chloride is present in an amount of about 0.5M to 1.5M, about 0.8M to about 1.2M, or about 0.9M.

In at least one embodiment, the electrolyte composition may include one or more additives. The one or more additives may be or include (but are not limited to) biodegradable or environmentally friendly nanomaterials. The biodegradable nanomaterial may be capable of or configured to provide and/or increase the structural strength of the electrolyte layer or electrolyte composition thereof without sacrificing the flexibility of the electrolyte layer or electrolyte composition thereof. Exemplary biodegradable nanomaterials of additives can be or include (but are not limited to) polysaccharide-based nanomaterials, inorganic nanomaterials, and the like, or combinations thereof. Exemplary polysaccharide-based nanomaterials can be or include (but are not limited to) one or more of cellulose nanocrystals, chitin nanocrystals, chitosan nanocrystals, starch nanocrystals, and the like, or combinations or mixtures thereof. Exemplary inorganic nanomaterials can be or include, but are not limited to, one or more of silicon oxide (e.g., fumed silica), aluminum oxide, layered silicate, or lime, or a combination or mixture thereof. Exemplary layered silicates may be or include (but are not limited to) one or more of the following: bentonite, kaolinite, dickite, nacrite, stapulgite, illite, halloysite, montmorillonite, hectorite, fluorohectorite (fluorohectorite), nontronite, beidellite, saponite, volkonskoite (volkonskoite), magadiite, sauconite, kenyaite (kenyaite), sauconite, muscovite, vermiculite, mica, hydromica, polysilicite (pheite), sodalite (brammalite), chlorite, or combinations or mixtures thereof.

The one or more additives may be present in an amount of at least 0.1% by weight based on the total weight of the hydrogel. For example, the one or more additives may be present in an amount of at least 0.1 wt%, at least 0.5 wt%, or at least 1 wt%, based on the total weight of the hydrogel. The one or more additives may also be present in an amount of 40% by weight or less based on the total weight of the hydrogel. For example, the one or more additives may be present in an amount of 40% by weight or less, 20% by weight or less, or 10% by weight or less, based on the total weight of the hydrogel.

In at least one embodiment, the electrolyte composition may include an aqueous solvent. For example, the electrolyte composition may include water. In at least one embodiment, the electrolyte composition may include a co-solvent. For example, the electrolyte composition may include water and an additional solvent. Exemplary co-solvents may be or include (but are not limited to) one or more of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, or combinations thereof. The co-solvent may include water in an amount of greater than about 20%, greater than about 30%, greater than about 40%, greater than about 50% to greater than about 60%, greater than about 70%, greater than about 80%, greater than about 85%, or greater than about 90%, by total weight or volume of the aqueous solvent of the electrolyte composition.

In at least one embodiment, the electrolyte composition includes a hydrogel of the copolymer and a salt, a solvent (such as water, or water and a co-solvent), one or more photoinitiators, optionally one or more additives, or a combination thereof dispersed in the hydrogel. For example, the electrolyte composition includes a hydrogel of the copolymer, a salt dispersed in the hydrogel, a solvent, one or more additives, or a combination or mixture thereof. In at least one embodiment, the electrolyte composition consists of or consists essentially of a hydrogel of the copolymer, a salt dispersed in the hydrogel, and a solvent (e.g., water, or water and a co-solvent). In another embodiment, the electrolyte composition consists of, or consists essentially of, a hydrogel of the copolymer, a salt dispersed in the hydrogel, a solvent, and one or more additives. The solvent, which may be water or a combination of water and a co-solvent, may constitute the balance of the hydrogel. Suitable electrolyte compositions, and processes and procedures for their production, are disclosed in International application No. PCT/US2020/046932, the disclosure of which is incorporated herein by reference in its entirety.

As previously described, the electrolyte layer 112, 212 of each biodegradable electrochemical device 100, 200 may be or include a solid aqueous electrolyte composition. The solid aqueous electrolyte composition may have mechanical and electrochemical properties sufficient for commercially available printed batteries or commercially useful printed batteries. For example, the solid aqueous electrolyte composition may have a young's modulus or storage modulus of greater than about 0.10 megapascals (MPa), greater than about 0.15MPa, or greater than about 0.20MPa, thereby providing the solid aqueous electrolyte composition with sufficient strength while maintaining sufficient flexibility to prevent it from breaking under stress. The solid aqueous electrolyte composition can have a young's modulus of less than or equal to about 100MPa, less than or equal to about 80MPa, less than or equal to about 60MPa, or less.

As used herein, the term or expression "yield strength" may refer to the maximum stress that a material is capable of withstanding or accepting before the material begins to permanently deform. The yield strength of the solid aqueous electrolyte composition may be about 5kPa or greater. For example, the yield strength of the solid aqueous electrolyte composition may be about 5kPa or greater, about 8kPa or greater, about 10kPa or greater, about 12kPa or greater, about 15kPa or greater, or about 20kPa or greater.

The solid aqueous electrolyte composition is electrochemically stable to both the anode active layer 108, 208 and the cathode active layer 110, 210 of each biodegradable electrochemical device 100, 200. For example, the solid aqueous electrolyte composition can maintain a stable open circuit voltage for a long period of time, thereby exhibiting electrochemical stability to the anode active layers 108, 208 and the cathode active layers 110, 210 of the respective biodegradable electrochemical devices 100, 200. In at least one embodiment, the solid aqueous electrolyte composition may be electrochemically stable upon contact with the electrode layer for at least one month, at least two months, at least three months, at least four months, at least five months, at least six months, at least one year or more.

The solid aqueous electrolyte compositions disclosed herein may be used in any electrochemical device, such as electrochemical cells, batteries, and/or biodegradable electrochemical devices 100, 200 disclosed herein. In a preferred embodiment, a solid aqueous electrolyte composition can be used that includes a Zn anode active layer and MnO ₂ In a battery of a cathode active layer.

The current collectors 104, 106, 204, 206 of each biodegradable electrochemical device 100, 200 may be capable of or configured to receive, conduct, and transmit electrical power. The example current collectors 104, 106, 204, 206 may be or include, but are not limited to, silver (e.g., silver particles and silver nanoparticles), carbon (e.g., carbon black, graphite, carbon fibers, carbon nanoparticles (e.g., carbon nanotubes), graphene, reduced Graphene Oxide (RGO)), and the like, or any combination thereof.

Method

Embodiments of the present disclosure may provide methods of manufacturing electrochemical devices (e.g., biodegradable electrochemical devices 100, 200 as disclosed herein). The method may include providing a biodegradable substrate. The method may further comprise depositing an electrode and/or electrode composition adjacent to or on the biodegradable substrate. Depositing an electrode may include depositing and drying a current collector of the electrode, and depositing and drying an active layer (i.e., anode or cathode material) adjacent to or on the current collector. The method may further comprise drying the electrode and/or the electrode composition. The electrode composition may be thermally dried (e.g., heated). The method may further comprise depositing a biodegradable, radiation curable electrolyte composition on or adjacent to the electrode composition. The method may further comprise radiation curing the biodegradable, radiation curable electrolyte composition. The biodegradable, radiation-curable electrolyte composition may be radiation-cured either before or after drying the electrode composition. The biodegradable substrate may be thermally compatible with optional thermal drying. For example, the biodegradable substrate can remain dimensionally stable (e.g., free of swelling (bucking) and/or curling) when heat dried. The method may include depositing a second electrode and/or electrode composition on or adjacent to the biodegradable, radiation curable electrolyte composition. In at least one embodiment, each of the first and second electrode compositions is a metal foil composition. The metal foil composition of the first electrode may be different from the metal foil composition of the second electrode.

In at least one embodiment, the electrochemical device, all components thereof, or substantially all components thereof are manufactured by a printing process. Printing processes may include deposition, stamping, spraying, sputtering, spraying, coating, layering, and the like. For example, one or more current collectors, one or more electrode compositions, biodegradable radiation curable electrolyte compositions, or combinations thereof may be deposited by a printing process. Exemplary printing processes can be or include, but are not limited to, one or more of screen printing, ink jet printing, flexographic printing (e.g., stamping), gravure printing, offset printing, inkjet printing, aerosol printing, typesetting, roll-to-roll (roll-to-roll) methods, and the like, or combinations thereof. In a preferred embodiment, the components of the electrochemical device are printed by screen printing.

In at least one embodiment, radiation curing the biodegradable radiation curable electrolyte composition includes exposing the electrolyte composition to radiant energy. The radiant energy may be ultraviolet light. Exposing the biodegradable radiation curable electrolyte composition to radiation energy can at least partially crosslink the biodegradable radiation curable electrolyte composition, thereby forming a hydrogel. The biodegradable radiation curable electrolyte composition is radiation curable at room temperature. In at least one embodiment, the biodegradable radiation curable electrolyte composition is cured under an inert atmosphere. For example, the biodegradable radiation curable electrolyte composition may be cured in nitrogen, argon, or the like. In another embodiment, the biodegradable radiation curable electrolyte composition is curable in a non-inert atmosphere.

In at least one embodiment, the biodegradable radiation curable electrolyte composition can be radiation cured in a time period of from about 5ms to about 100 ms. For example, the biodegradable radiation curable electrolyte composition can be radiation cured for a time of about 5ms, about 10ms, about 15ms, about 20ms, about 30ms, about 40ms, or about 50ms to about 60ms, about 70ms, about 80ms, about 85ms, about 90ms, about 95ms, or about 100 ms. The length of time sufficient to radiation cure the biodegradable radiation curable electrolyte composition may be determined at least in part by the power output of the ultraviolet light.

In at least one embodiment, the method may further include depositing an adhesive, such as a biodegradable adhesive, to provide the seal 116, 118, 216, 218 of each biodegradable electrochemical device 100, 200. For example, the method may include depositing a layer of adhesive to bond substrates or portions of substrates (e.g., areas around tabs 124, 126, 224, 226) of the electrochemical device to one another. In some embodiments, the adhesive may be a hot melt adhesive. In another embodiment, the electrochemical device may be free or substantially free of any binder. For example, the biodegradable substrate may be weldable and/or heat sealable without the use of additional adhesives.

In at least one embodiment, the biodegradable substrate may be a continuous web or may be supported by a continuous web. As used herein, the term "web" may refer to a moving support surface, such as a conveyor belt. In at least one example, a plurality of electrochemical devices are printed simultaneously as separate or joined elements or components on a continuous web. For example, individual components of multiple electrochemical devices may be printed simultaneously as separate or connected components on a continuous web as an array in a parallel flow path. As used herein, the term or expression "connected element" or "connected component" may refer to elements or components, respectively, in an electrochemical device that are physically touching, overlapping, or otherwise in contact with each other. Exemplary connected elements may be or include an active layer (e.g., a cathode active layer or an anode active layer) deposited adjacent to or on top of a current collector layer, a current collector layer and copper tape tabs, or an electrolyte layer on top of an active anode/cathode layer.

In at least one embodiment of the exemplary biodegradable electrochemical device, a solid aqueous electrolyte thereof and methods of synthesizing and manufacturing the same are available, and layers of various materials (including current collectors, cathode/anode materials, binders, and electrolytes) need to be printed with high fidelity and high precision. In addition, maintaining moisture in the aqueous electrolyte is critical to cell performance by maintaining dissolved salts to achieve good ionic conductivity, while printing biodegradable or compostable cells shortens life due to water loss by evaporation through the biodegradable substrate, which may be a polylactic acid (PLA) film. Such electrochemical devices may have a biodegradable polymer composite film encapsulation pouch having a biodegradable barrier layer. Exemplary biodegradable encapsulating materials may be or include, but are not limited to, one or more of polylactic acid (PLA), polylactic-co-glycolic acid (PLGA), silk fibroin, chitosan, polycaprolactone (PCL), polyhydroxy Ding Suanzhi (PHB), rice paper, cellulose, or combinations or composites thereof.

In at least one embodiment, a flexible biodegradable electrochemical device comprising an anode, a cathode, and an electrolyte composition may have a biodegradable moisture or water vapor barrier or barrier layer that forms an enclosure, film, or pouch around the exterior of the electrochemical device to prevent evaporation of moisture present within the aqueous electrolyte material; the electrolyte composition includes a crosslinked biodegradable polymer material printed between an anode and a cathode that is radiation curable prior to crosslinking. In such embodiments, since the entire electrochemical device is biodegradable, the device has an extended service life due to the improved water vapor barrier or moisture barrier layer properties of the encapsulation pouch, and it is biodegradable and/or biodegradable at the end of the service life. The function of the biodegradable water vapor barrier or enclosure is to provide a moisture barrier layer to prevent evaporation of water from the aqueous electrolyte composition within the electrochemical device, thereby extending the useful life of the electrochemical device. It is noted that, with respect to the water vapor barrier or moisture barrier layers described herein, while certain embodiments of the electrochemical devices may have a significant amount of water or moisture, other solvents or vaporizable materials may also contribute to the prolonged and acceptable operation of the electrochemical devices encapsulated within the water vapor barrier of the present disclosure.

The biodegradable water vapor barrier of each biodegradable electrochemical device can remain stable at a temperature of about 50 ℃ to about 150 ℃. As used herein, the term "stable" or "stability" may refer to the ability of a substrate to resist dimensional changes and maintain structural integrity when exposed to temperatures of about 50 ℃ to about 150 ℃. For example, the degradable biological vapor barrier can or is configured to maintain structural integrity after exposure to a temperature of about 50 ℃ to about 150 ℃, wherein the dimensional change is less than about 20%, less than about 15%, or less than about 10%. In one example, each biodegradable water vapor barrier may be stable (e.g., less than 20% change in size) at a temperature of about 50 ℃, about 60 ℃, about 70 ℃, about 80 ℃, about 90 ℃, about 100 ℃, or about 110 ℃ to about 120 ℃, about 130 ℃, about 140 ℃, or about 150 ℃. In another example, each biodegradable water vapor barrier can be stable at a temperature of at least 100 ℃, at least 105 ℃, at least 110 ℃, at least 115 ℃, at least 120 ℃, at least 125 ℃, at least 130 ℃, at least 135 ℃, at least 140 ℃, or at least 145 ℃. In at least one embodiment, the biodegradable water vapor barrier may be stable at a temperature of about 50 ℃ to about 150 ℃ for about 5 minutes to about 60 minutes or more. For example, the biodegradable water vapor barrier may be stable at the above temperatures for a period of time of about 5 minutes, about 10 minutes, about 20 minutes, or about 30 minutes to about 40 minutes, about 45 minutes, about 50 minutes, about 60 minutes, or longer.

In at least one embodiment, the biodegradable vapor barrier material is weldable, bondable, and/or permanently heat sealable without the use of an additional adhesive. For example, the biodegradable water vapor barriers for electrochemical device enclosures described herein may be weldable and/or bondable to one another without the use of a corresponding seal. Exemplary biodegradable water vapor barrier materials that are weldable and/or bondable to one another may be or include, but are not limited to, thermoplastics such as polylactic acid (PLA), polylactides modified with a nucleating agent to increase crystallinity (such as polylactide modified with a nucleating agent D (PLA-D) and polylactide modified with a nucleating agent E (PLA-E)), polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), blends of PLA and Polyhydroxybutyrate (PHB), PHB-based blends, and the like, or combinations thereof. As used herein, the terms or expressions "bondable," "weldable," and/or "permanently heat sealable" may refer to the ability of a material (e.g., a substrate) to heat seal two surfaces to one another or to permanently join two surfaces to one another by heating or melting.

In some embodiments, the biodegradable envelope, bag, or vapor barrier may be made of a metallized biodegradable polylactic acid (PLA) film, such as an aluminum metallized polylactic acid film. The metallic surface layer providing metallization may be aluminum. In certain embodiments, the metallized layer may include aluminum, other suitable metals or alloys, ceramics, clays, hybrid materials of inorganic-organic biopolymers, and combinations thereof. Alternative embodiments may have multiple layers of metal on the inner layer, the outer layer, or both of the multilayer film. The PLA film may be biaxially stretched to improve the physical properties of the encapsulated bag. Still other embodiments may incorporate additives into the film to provide enhanced moisture barrier properties. In alternative embodiments, the biodegradable envelope, pouch, or water vapor barrier for an electrochemical device may have a single layer, or multiple layers in combination with one or more materials. The metallized layer film or barrier may provide a thickness of about 1nm to about 100nm, about 5nm to about 50nm, or about 10nm to about 40 nm. In certain examples, the overall thickness of the monolayer film or barrier may be from about 1 μm to about 100 μm, from about 40 μm to about 80 μm, or from about 50 μm to about 75 μm. On a base film layer such as PLA, the metallized layer of the water vapor barrier may have a thickness of about 0.5nm to about 100nm, about 5nm to about 50nm, or about 5nm to about 25 nm.

In certain examples, the biodegradable envelope, bag, or vapor barrier may be made of a multi-layer composite material constructed by extruding or laminating a biodegradable polymer on each side of a thin metal foil (e.g., aluminum). Unlike the metallized polymer layer in the biodegradable envelope, the thin continuous metal layer in such a multi-layer laminate composite can provide a strong barrier layer in combination with one or more biodegradable envelope layers. The advantage of such a multilayer laminate structure is that the continuous metal film forms such layers: which is more effective in preventing water penetration through the composite while also providing the option of providing a thicker metal layer or layers of aluminum or metals. Thus, the metal layer providing the water vapor barrier may be from about 1 μm to about 200 μm, or from about 5 μm to about 150 μm, or from about 10 μm to about 100 μm. Metal foil layers according to the present disclosure are less prone to problems such as pinholes in aluminum or metal layers, which are more prevalent in metal films formed by sputtering or other deposition methods described herein. Pinholes are present in the metal or other barrier layer within the biodegradable envelope, bag or vapor barrier, which in some cases allow some water to permeate through the composite.

For certain examples having multilayer composites according to the present disclosure, several methods may be employed to form these multilayer laminates. In a first example, a pre-existing polymer sheet may be pressed against one or each side of an aluminum sheet at an appropriate temperature and pressure, wherein the adhesion of the polymer sheet to the aluminum or metal foil is achieved or enhanced using one or more mutually staggered or interposed adhesive tie layers (tie layers). In a second example, the polymer layer and adhesive tie layer may be melt extruded directly as a thin film onto the surface of an aluminum or other metal foil using a multilayer film casting process known to those skilled in the art. Other metal foils or films comprising metals such as magnesium, titanium, iron, nickel, copper, zinc, or alloys or mixtures thereof may be used in accordance with the present disclosure.

In certain embodiments, other materials known to have water vapor barrier properties may be used. These materials must meet the biodegradable and/or compostable requirements and include materials (e.g., beeswax), plasticizers and alternative biodegradable polymer composite films. In alternative embodiments, the water vapor barrier is not part of the electrochemical device substrate, and may be used with higher temperature stability and tolerance, and a wider range of temperature tolerance, than biodegradable materials, polymers, or composites. Embodiments of electrochemical devices having a biodegradable encapsulant or water vapor barrier with moisture barrier properties may exhibit reduced Water Vapor Transmission Rate (WVTR) as compared to electrochemical devices without such barriers, layers, or encapsulates, exhibiting a WVTR of about 0% to about 5% within 24 hours, about 0.1% to about 2% within 24 hours, or about 0.5% to about 1% within 24 hours. WVTR may also be expressed as a percentage of the total weight of water loss to the total weight of an electrochemical device including an encapsulant or moisture barrier. Biodegradable packages having moisture barrier properties in accordance with the present disclosure, as compared to electrochemical devices without such barrier layers or encapsulants Embodiments of the seal or the water vapor barrier electrochemical device may exhibit reduced Water Vapor Transmission Rate (WVTR), the water vapor barrier exhibiting a WVTR of about 0.0g/m ² 24 hours to about 10g/m ² For/24 hours, about 0.5g/m ² 24 hours to about 5g/m ² For/24 hours, or about 1g/m ² 24 hours to about 2g/m ² And/or 24 hours. WVTR is expressed herein as weight percent or weight percent (wt%) of the total electrochemical device. Certain examples of electrochemical devices having a biodegradable enclosure or vapor barrier with moisture barrier properties may exhibit reduced vapor transmission rate (WVTR) compared to electrochemical devices without such a barrier layer or enclosure, the vapor barrier of the present disclosure exhibiting a WVTR of about 0mg/cm ² 24 hours to about 5.0mg/cm ² 24 hours, about 0.1mg/cm ² 24 hours to about 1mg/cm ² /24 hours, or about 0.1mg/cm ² 24 hours to about 0.5mg/cm ² And/or 24 hours.

In some embodiments, the electrochemical device may be arranged such that the cell or electrochemical device is housed in an enclosure or entirely within a water vapor barrier as described with improved water vapor barrier properties, and oriented or arranged such that the cathode and anode are in a side-by-side or transverse X-Y planar geometry, as shown in fig. 1. In alternative embodiments, the electrochemical device may be arranged such that the cell or electrochemical device is housed in an enclosure as described above, which has improved water vapor barrier properties, and is oriented or arranged such that the cathode and anode are in a stacked geometry, as shown in fig. 2.

Embodiments of the present disclosure may provide methods of manufacturing, producing, or otherwise encapsulating electrochemical devices having improved moisture barrier properties or water vapor barrier properties. The method can include orienting a first metallized PLA film having four sides and a second metallized PLA film having four sides with a non-metallized side of the first metallized PLA film facing a non-metallized side of the second metallized PLA film. One or more edges of the first and second metallized PLA films may be sealed together. A biodegradable or compostable electrochemical device can be placed between the first metallized PLA film and the second metallized PLA film, and then the sides of the first metallized PLA film and the second metallized PLA film are sealed together such that one or more electrodes of the electrochemical device are exposed through at least one of the four sides.

The method may further comprise the steps of: a first metallized PLA film having four sides is oriented on the top surface of the electrochemical device with the non-metallized side facing the electrochemical device. The second metallized PLA film is positioned on the bottom surface of the electrochemical device with the non-metallized side facing the electrochemical device. All four sides of the first metallized PLA film and four sides of the second metallized PLA film may be sealed together such that one or more electrodes are exposed through at least one of the four sides. An encapsulant or vapor barrier fabricated from a biodegradable aluminized polymer barrier layer in combination with a surface coating and/or polymer additive in this manner may reduce or prevent the loss of water vapor from a biodegradable or compostable electrochemical device. By preventing evaporation of the electrolyte solvent over time, such a device can significantly extend the useful life of a biodegradable or compostable electrochemical device.

Examples

The examples and other embodiments described herein are illustrative and are not intended to limit the full scope of the compositions and methods of the present disclosure. Equivalent alterations, modifications and variations of specific embodiments, materials, compositions and methods may be made within the scope of the present disclosure, with substantially similar results.

Comparative example 1

Comparative example 1 describes surrogate testing in connection with embodiments of the biodegradable battery configurations described herein having improved moisturization. Fig. 3 illustrates a cross-sectional view of a comparative example of a fully assembled surrogate of a biodegradable battery assembly with a water vapor barrier according to one or more embodiments. The surrogate test was performed to measure the loss of moisture through the PLA-D biodegradable substrate under conditions similar to a fully assembled biodegradable battery. Comparative example 1 is a surrogate battery assembly 300 having a membrane envelope 304 surrounding a piece of filter paper 302, the filter paper 302 being a surrogate for an aqueous electrolyte battery composition. Two sheets of PLA-D biaxially oriented film having a thickness of 80 μm were cut into square shapes of 2cm by 3 cm. The two cut films were laminated together in a similar orientation. Three of the four sides of the film sheet were heat sealed together using an MSK-130 heat sealer, available from MTI corporation, set at 170 ℃ for 5 seconds to form a bag or envelope having a single 3cm unsealed side. A1 cm square piece of whatman1825-150 filter paper 302 was placed in a 2cm 3cm bag 304. The bag with filter paper 302 is then weighed and peeled. 3 drops of Deionized (DI) water were added to the paper in the pouch and then the remaining open edge of the pouch was sealed to form a heat seal 306 under the same conditions as previously described. The weight of the bag was measured over time to determine the loss of water. Surrogate testing involved creating a full-sized sealed base structure to which a known, measured amount of water was added to reflect a similar amount in a fully assembled biodegradable cell. The water loss over time is then measured by periodically weighing surrogate battery assembly 300. This test protocol was then repeated with experimental examples 1-3 to evaluate the various embodiments of the membrane encapsulation to inhibit water permeation loss of the water-based electrolyte composition within the biodegradable electrochemical device.

Example 1

Fig. 4 illustrates a cross-sectional view of a fully assembled surrogate of the electrochemical device assembly of example 1, having a water vapor barrier according to one or more embodiments. Two 4cm x 4cm square pieces of Enviromet HS 75 μm thick outline PLA manufactured by Celplast, toronto Ontario, canada were oriented and laminated together with the PLA side facing inward to form an enclosure 400 for an electrochemical device. An MSK-130 heat sealer was used, wherein the soft mold was set at 170 ℃ for 3 seconds to seal three of the four sides of the sheet together, creating an envelope 400 with one open side, resulting in an envelope 400 with an inner PLA layer 410 and an outer aluminum layer 412. The water-soaked filter paper 402 and PLA-D sealed pouch 404 sealed at the sides similar to the embodiment described for comparative example 1 were then placed inside the PLA-al pouch 400 and the remaining sides 414 were sealed with MSK-130. The weight of the bag 400 is measured over time to determine the loss of water.

Example 2

Fig. 5 illustrates a cross-sectional view of a fully assembled surrogate of the electrochemical device assembly of example 2 having a water vapor barrier according to one or more embodiments. Eight pieces of 4cm x 4cm square Enviromet 75 μm thick, aluminum PLA were oriented and laminated together with the PLA side facing inward to form an encapsulating pouch or water vapor barrier 500 for an electrochemical device having four layers. An MSK-130 heat sealer was used, wherein the soft mold was set at 170 ℃ for 3 seconds to seal three of the four sides of each sheet together, creating an open sided envelope 500. In this embodiment, the wall of the envelope 500 is composed of a first layer (with a first PLA layer 508 and a first aluminum layer 510), a second layer (with a second PLA layer 512 and a second aluminum layer 514), a third layer (with a third PLA layer 516 and a third aluminum layer 518), and a fourth layer (with a fourth PLA layer 520 and a fourth aluminum layer 522), forming a four-sheet laminate Enviromet Aluminized PLA. The water-impregnated filter paper 502 and PLA-D enclosed pouch 504 sealed at edge 506 similar to the embodiment described for comparative example 1 are then placed into the PLA-al pouch 500 and the remaining edge 522 is sealed with MSK-130. Over time, the weight of the envelope 500 is measured to determine the loss of water.

Example 3

Fig. 6 is a cross-sectional view of a fully assembled surrogate of the electrochemical device assembly of example 3 having a water vapor barrier according to one or more embodiments. Two pieces of 4cm x 4cm square Enviromet 75 μm thick, aluminum PLA were oriented and laminated together with the PLA side facing inward, forming an envelope pouch 600 with a single water vapor barrier layer for an electrochemical device. An MSK-130 heat sealer was used, wherein the soft mold was set at 170 ℃ for 3 seconds to seal 3 of the 4 sides together, creating an open sided envelope 600. In this embodiment, the wall of the envelope bag 600 is composed of a PLA layer 604 and an aluminium layer 606. A 1cm piece of square Whatman 1825-150 filter paper 602 was placed in a 4cm x 4cm envelope 600. The bag 600 with the paper sheet 602 inside is then weighed and peeled. 3 drops of deionized water were added to the paper 602 in the bag 600 and the last open edge of the bag was then sealed with MSK-130 as described above. The weight of the bag was measured over time to determine the loss of water.

Examples 4, 5, 6 and 7

Fig. 7 illustrates a cross-sectional view of one example of a surrogate for an electrochemical device assembly having a multi-layered encapsulated structure according to the present disclosure. In the multilayer encapsulation structure 700, the first and second sides of the metal barrier layer 702 have a first adhesive tie layer 704 and a second adhesive tie layer 706 deposited on the metal barrier layer 702. It should be noted that in some material configurations of the multi-layer composite structure 700, an adhesive tie layer is not required, but in other examples, an adhesive tie layer is required to be present where no adhesive is present and the polymer does not adhere to aluminum or other metal surfaces. In some examples, the composition of the adhesive tie layers 704, 706 are biodegradable, but because they are sufficiently thin compared to the metal and polymer layers, they may be made partially or entirely of non-biodegradable materials. In these examples, the relative weight percent of any non-biodegradable material will be less than 10 weight percent of the entire encapsulating material. In some examples, the aluminum or metal barrier 702 surface may be surface treated to enhance adhesion of one or more layers to the metal barrier layer 702 surface, such as plasma or corona treatment. It is contemplated that the outer first biodegradable polymer layer 708 and the second biodegradable polymer layer 710 will both be composed of the same material, however, in some instances, the first biodegradable polymer layer 708 and the second biodegradable polymer layer 710 may not be composed of the same material, and thus the material composition of the adhesive tie layers 704, 706 may also be different, as each polymer type used in the first biodegradable polymer layer 708 and the second biodegradable polymer layer 710 requires optimized adhesion. The metal layer or metal barrier layer described herein provides a water impermeable layer (moisture impermeable layer or moisture impenetrable layer) for the multilayer encapsulation structure of the present disclosure. In certain examples of such multilayer encapsulation structures, the metal layer or metal barrier layer is such that no water, moisture, or solvent passes through the encapsulation.

Example 4: a semi-structured multilayer composite was prepared using a commercial three-layer PLA film as the tie layer. A formulation of commercial extrusion grade PLA obtained from cobion blended with a crystallization agent (reagent D, luminey D070 of cobion) was melt extruded to obtain a PLA sheet of approximately 100 μm thickness. A multilayer laminate was prepared using a 40 μm thick aluminum foil obtained from All films inc., ohio, USA, a sheet of extruded PLA-D polymer, and a three layer PLA film Evlon EV-HS1 as an intermediate adhesive tie layer. The multilayer laminate was pressed at 120℃for 20 minutes at 5000 PSI. The resulting multilayer film can be considered half of the multilayer structure detailed in fig. 7. However, since the aluminum layer served as a water vapor barrier layer, this half-structure was sufficient to demonstrate barrier properties in the surrogate evaluations according to the present disclosure. A complete structure may only be required in some instances to protect the aluminum layer from mechanical damage by adding a polymeric scratch resistant layer. The same method as for the half-structure can be used to fabricate the complete structure.

Example 5: a semi-structured multilayer composite is prepared using a non-biodegradable polyamide based adhesive as the tie layer. A thin layer of polyamide-based adhesive powder (Evonik Vestamelt Hylink) was coated on 40 μm thick aluminum foil using an electrostatic spray gun and then placed in an oven at 140 ℃ for 10 minutes. The PLA-D sheet obtained in the manner detailed in example 4 was then applied to the adhesive tie layer side of the aluminum foil and was pressed at 120 ℃ for 20 minutes at 5000 PSI. The weight of the adhesive tie layer was 2mg/cm ² While the weight of the half-structure is 32.4mg/cm ² This results in an adhesive tie layer weight of about 6% by weight based on the total weight of the half-structure. The adhesive tie layer weight of the fully symmetrical multilayer structure was calculated to be 54.4mg/cm ² 4mg/cm in (B) ² Or 7.4 wt% of a non-biodegradable adhesive tie layer.

Example 6: semi-structured multilayer composites were prepared using Polycaprolactone (PCL) film as the adhesive tie layer. PCL adhesive tie layer films were obtained by pressing the CAPA6500 PCL pellets obtained from Ingevity at 100 ℃,5000PSI for 20 minutes. A multilayer laminate was prepared using 40 μm thick aluminum foil, a sheet of extruded PLA-D (as example 4 and used in accordance with the present disclosure) and PCL film as the adhesive tie layer. The multilayer laminate was pressed at 120℃for 20 minutes at 5000 PSI.

Example 7: a semi-structured multilayer composite was prepared using amorphous grade PLA film as the adhesive tie layer. An amorphous PLA layer film was prepared by pressing PLA pellets at 200 ℃ for 20 minutes at 5000 PSI. A multilayer laminate was prepared using 40 μm thick aluminum foil, a sheet of extruded PLA-D (as described in example 4) and interdigitated amorphous PLA film as an adhesive tie layer. The multilayer laminate was pressed at 120deg.C and 5000PSI for 20 minutes

In certain embodiments, the multilayer composites of examples 6 and 7 can be made in one step by direct melt extrusion of a bilayer of adhesive tie layer and PLA film on an aluminum roll, as is common in the multilayer packaging manufacturing industry.

To demonstrate the barrier properties of the multilayer composites prepared in examples 4, 5, 6 and 7, hermetically sealed bags of each multilayer laminate (semi-structured) were prepared by cutting sheets of similar dimensions and heat sealing them on their edges by pressing them between jaws of a hand-held heat sealer set at 200 ℃ for 5 seconds. Each pocket is filled with paper towels saturated with water. The weight of each bag was then measured daily to monitor the water penetration through the multi-layer composite and subsequent evaporation.

Fig. 8 shows a graph of water loss in milligrams per square centimeter versus time in days for the comparative example of fig. 3 compared to examples 1 to 7 of fig. 4, 5, 6 and 7, respectively. For each example, the cumulative water loss in milligrams per square centimeter was measured by weight every 24 hours, then normalized by surface area, and plotted. Comparative example 1 having only a PLA-D substrate as the barrier layer showed about 15mg/cm ² I.e. the total water loss on day 9. Example 1 using an additional aluminized PLA barrier layer showed significantly reduced cumulative water loss at day 9 of about 1.34mg/cm ² . Example 2 with four aluminized PLA barrier layers in combination, on day 9, showed a significant reduction in cumulative water loss0.66mg/cm ² . Example 3, which used only aluminized PLA as the barrier layer, showed a moderately improved reduction in cumulative water loss on day 9 of 2.84mg/cm compared to the total water loss at similar times for comparative example 1 ² . The multilayer samples in examples 4, 5, 6 and 7 had little or negligible water loss at day 9. The overall results are shown in tables 1 and 2.

TABLE 1

TABLE 2

Continuity test

With the embodiments of biodegradable batteries having a barrier layer described herein, problems may occur that affect the continuity of the battery tab, particularly if heat sealing is used across the tab. This problem was evaluated by assembling several full-size batteries (similar to example 2) using aluminized PLA as the outer barrier layer. The MSK sealer uses a lower temperature, 135 ℃, to prevent unnecessary thermal exposure and potential damage to the battery tabs while also providing a robust seal. The MSK sealer was set to a lower temperature of 135 ℃ in the soft mold for a longer period of 6 seconds. The device was found to be completely normal after heat sealing, with no loss of tab continuity.

The present disclosure has been described with reference to exemplary embodiments. While a limited number of embodiments have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the foregoing detailed description. The disclosure should be construed to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. An electrochemical device, comprising:

an anode;

a cathode;

an electrolyte composition disposed between the anode and the cathode; and

a water vapor barrier comprising a biodegradable material, wherein the water vapor barrier comprising a biodegradable material is used to reduce water vapor escaping from the electrochemical device.

2. The electrochemical device of claim 1, wherein the water vapor barrier further comprises polylactic acid (PLA).

3. The electrochemical device of claim 1, wherein the water vapor barrier further comprises a metallized coating.

4. The electrochemical device of claim 3, wherein the metallized coating comprises aluminum.

5. The electrochemical device of claim 1, wherein the water vapor barrier further comprises a plurality of layers.

6. The electrochemical device of claim 1, wherein the water vapor barrier further comprises a water impermeable layer.

7. The electrochemical device of claim 6, wherein the water impermeable layer comprises a metal.

8. The electrochemical device of claim 7, wherein the metal layer has a thickness of about 1 μιη to about 150 μιη.

9. The electrochemical device of claim 1, wherein the anode is printed directly on the water vapor barrier.

10. The electrochemical device of claim 1, wherein the cathode is printed directly on the water vapor barrier.

11. A water vapor barrier, comprising:

a biodegradable material, the biodegradable material comprising a polymer; and

a metal layer coating disposed on the biodegradable material.

12. The water vapor barrier of claim 11, wherein the polymer comprises polylactic acid (PLA).

13. The water vapor barrier of claim 11, wherein the metal layer comprises aluminum.

14. The water vapor barrier of claim 11, further comprising a plurality of layers.

15. The water vapor barrier of claim 11, wherein the metal layer has a thickness of about 1 μιη to about 150 μιη.

16. The water vapor barrier of claim 11, further comprising:

an anode;

a cathode; and

an electrolyte composition disposed between the anode and the cathode; and

a water vapor barrier comprising a biodegradable material encapsulating the anode, the cathode, and the electrolyte composition; and is also provided with

Wherein the anode, the cathode, and the electrolyte composition are encapsulated by the water vapor barrier.

17. An electrochemical device, comprising:

an anode;

a cathode;

an electrolyte composition disposed between the anode and the cathode; and

a water vapor barrier comprising a biodegradable material, wherein:

the water vapor barrier comprising a biodegradable material is for preventing water vapor from escaping from the electrochemical device; and

the water vapor barrier comprising biodegradable material further comprises a polylactic acid (PLA) layer and a metal layer; and

the electrochemical device has a Water Vapor Transmission Rate (WVTR) of less than or equal to 1mg/cm within 24 hours ² 。

18. The electrochemical device of claim 17, wherein the water vapor barrier further comprises a plurality of layers.

19. The electrochemical device of claim 17, wherein the metal layer has a thickness of about 0.1 μιη to about 10 μιη.

20. The electrochemical device of claim 17, wherein the metal layer has a thickness of about 20 μιη to about 150 μιη.