Improving cycle stability and kinetics of rechargeable al / co2 batteries by functional cathode materials

Abstract

A battery is disclosed, including an anode, which may include a metal, a cathode, which may include a hydrophobic paper and an electrolyte separating the anode and the cathode, and where the hydrophobic paper may include a coating on a surface of the hydrophobic paper, and the battery uses carbon dioxide gas as an active cathode material. Examples of the battery include where the coating on the surface of the hydrophobic paper may include a high porosity and a high surface area. The coating on the surface of the hydrophobic paper may include an electroconductive carbon black or graphene. The hydrophobic paper may include carbon fiber. The coating on the surface of the hydrophobic paper faces towards the electrolyte or away from the electrolyte. The battery is configured to operate reversibly while charging and discharging.

Description

Improving Cycle Stability and Kinetics of Rechargeable AI / CO2 Batteries by Functional Cathode MaterialsREFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 588,356, filed on October 6, 2023, which is hereby incorporated by reference in its entirety.STATEMENT OF GOVERNMENT INTEREST

[0002] This invention was made with government support under 2119688, awarded by the National Science Foundation. The government has certain rights in the invention.TECHNICAL FIELD

[0003] The present teachings relate generally to rechargeable batteries and, more particularly, to rechargeable batteries using functional cathode materials.BACKGROUND

[0004] Rechargeable batteries are a key component various areas of technology, powering devices from smartphones and laptops to electric vehicles and can provide renewable energy storage systems. The ability to be recharged and used multiple times offers significant advantages over single-use batteries, in terms of cost savings and environmental impact.

[0005] Metal / carbon dioxide batteries have emerged as a potential avenue for advancing energy storage technology and sequestering carbon dioxide from ambient air. Aluminum (Al) is an anode material of interest for electrochemical CO2 capture and conversion due to its lower cost and reactivity in comparison to lithium and sodium anode materials, making it safer and more accessible for manufacturing. The abundance of aluminum across various regions of the world further adds to the interest in aluminum. Previous studies indicate that aluminum based batteries possess a significant discharge capability with the introduction of a small amount of oxygen, however, these batteries are not rechargeable.

[0006] Therefore, it is desirable to fabricate rechargeable batteries synthesized from metal / carbon dioxide materials, that exhibit sufficient reversible discharge and charge behavior.SUMMARY

[0007] The following presents 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 present teachings, nor to delineate the scope of the disclosure. Rather, its primary purpose is merely to present one or more concepts in simplified form as a prelude to the detailed description presented later.

[0008] A battery is disclosed, including an anode, which may include a metal, a cathode, which may include a hydrophobic paper and an electrolyte separating the anode and the cathode, and where the hydrophobic paper may include a coating on a surface of the hydrophobic paper, and the battery uses carbon dioxide gas as an active cathode material. Implementations of the battery include where the coating on the surface of the hydrophobic paper may include a high porosity and a high surface area. The coating on the surface of the hydrophobic paper may include an electroconductive carbon black or graphene. The hydrophobic paper may include carbon fiber. The coating on the surface of the hydrophobic paper faces towards the electrolyte or away from the electrolyte. The metal may include aluminum. The battery is configured to operate reversibly while charging and discharging. The battery further may include aluminum iodide.

[0009] A battery assembly is disclosed, including a battery chamber, which may include an anode comprising a metal, a cathode, which may include a hydrophobic paper coated on a surface, and an electrolyte separating the anode and the cathode, and where the battery uses carbon dioxide gas as an active cathode material. The assembly also includes an inlet port in communication with the battery chamber configured to introduce carbon dioxide gas into the battery chamber. The assembly also includes a spring-actuated outlet port configured to relieve pressure within the battery chamber. Implementations of the battery assembly can include where the coating on the surface of the hydrophobic paper may include an electroconductive carbon black or graphene. The hydrophobic paper may include carbon fiber. The coating on the surface of the hydrophobic paper faces towards the electrolyte or faces away from the electrolyte. The metal may include aluminum. The battery is configured to operate reversibly while charging and discharging. The battery further may include aluminum iodide.

[0010] A battery is disclosed, including an anode, a cathode, which may include a hydrophobic paper and a carbon fiber coated on a surface with a coating which may include electroconductive carbon black and graphene. The battery also includes an electrolyte separating the anode and the cathode, and where the coating on the surface of the hydrophobic paper faces towards the electrolyte, and the battery uses carbon dioxide gas as an active cathode material.

[0011] The features, functions, and advantages that have been discussed can be achieved independently in various implementations or can be combined in yet other implementations further details of which can be seen with reference to the following description.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present teachings and together with the description, serve to explain the principles of the disclosure. In the figures:

[0013] FIGS. 1A and IB depict a schematic of a battery configured for utilizing carbon dioxide as an active cathode material and an enlarged portion thereof, respectively, in accordance with the present disclosure.

[0014] FIGS. 2A and 2B are plots depicting voltage vs. capacity and current vs voltage for devices of the present disclosure.

[0015] FIGS. 3A and 3B depict several battery configurations showing different locations of cathode coatings, and a plot of current vs. voltage demonstrating the effect, respectively, in accordance with the present disclosure.

[0016] FIG. 4 is a plot of current vs. voltage of a battery having improved current density and cyclability, in accordance with the present disclosure.

[0017] FIGS. 5A and 5B are magnified images of carbon fiber coated with carbon black, and carbon fiber coated with carbon black and graphene, respectively, in accordance with the present disclosure.

[0018] It should be noted that some details of the figures have been simplified and are drawn to facilitate understanding of the present teachings rather than to maintain strict structural accuracy, detail, and scale.DETAILED DESCRIPTION

[0019] 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, similar, or like parts.

[0020] Metal-CCF batteries have emerged as a promising solution for advancing energy storage technology and sequestering carbon dioxide from ambient air. Aluminum (Al) is an anode material of interest for electrochemical CO2 capture and conversion due to its lower cost and reactivity in comparison to lithium and sodium anode materials, making it safer and more accessible for manufacturing. The abundance of aluminum across various regions of the world further adds to its attractiveness. Additionally, aluminum boasts a high specific energy of 2980A hour / kg, suggesting that its electrochemical conversion with CO2 can produce comparatively large amounts of electrical energy. Previous studies show that Aluminum / CO?bateries possess an advantageous discharge capability with the introduction of a small amount of oxygen, however, these bateries are not rechargeable.

[0021] By utilizing a homogeneous iodine-based redox mediator, the present disclosure provides a demonstration that an AI-CO2 batery can achieve reversible discharge and charge with minimal overpotential of 0.05V, reducing stripping / plating overpotentials by 40% across various current rates compared to an unmodified imidazolium -based ionic liquid electrolyte. This is achieved by replacing oxygen gas with aluminum iodide in the electrolyte, which maintains high discharge capacity and enables the batery to be recharged for up to 12 cycles at a 20 mA / gcarbon rate.

[0022] Examining the discharge and charge rates of different cathode materials can enable demonstration of the improvement in cycle stability. By utilizing functional carbon-based materials with increased surface area, heteroatom doping and unique pore structure as the cathode, it can be demonstrated that the rechargeable AI-CO2 batery can enhance CO2 reduction during the discharge processes, thereby improving reaction kinetics.

[0023] Higher surface area and porous materials facilitate faster electron transfer during the electrochemical reactions while allowing beter CO2 diffusion into the cathode, improving reaction rates.

[0024] In an exemplary aluminum / carbon dioxide (CO2) batery system, a higher surface area and porous materials facilitate faster electron transfer during the electrochemical reactions while allowing beter CO2 diffusion into the cathode, improving reaction rates.

[0025] One example cathode material used in an aluminum / C02 batery is a mixture of ketjenblack and Polyvinylidene fluoride with a ratio of 2: 1 coated on a Toray Carbon Paper 030, Wet Proofed. Ketjenblack is an amorphous product and the morphology network of this material plays a role in the reduction of CO2 acting as a catalyst and also as a cathode.

[0026] Another exemplary material being evaluated is a combination of ketjenblack mixed with graphene and Polyvinylidene fluoride (PVDF) in a ratio of 2:2: 1 coated on a Toray Carbon Paper 030, Wet Proofed. This material increases the conductivity of the cathode material allowing the batery to have higher current densities and beter cycle stability during the charge and discharge. The same 2:2: 1 ratio of ketjenblack:graphene:PVDF was coated on both sides of the Toray Carbon Paper 030, Wet proofed. This new setup enhances the kinetics of the cathode active material increasing the current density about three times more than the initial setup and also increasing the cyclability of the batery from seven to fifteen cycles.

[0027] FIGS. 1A and IB depict a schematic of a batery configured for utilizing carbon dioxide as an active cathode material and an enlarged portion thereof, respectively, in accordance with the present disclosure. Shown in IG. 1A is a batery 100 which includes a cathode 102 and an anode 104. The batery further includes an inlet valve 106 which can control the flow of an inlet gas 110 and an outlet valve 108 which can control flow of an outlet gas 112. Disposed between the cathode 102 and the anode 104 is a batery chamber 114 which includes a spring 116. Severalgaskets 118, which can be comprised of polytetrafluoroethylene, for example or other gasket 120 materials are located in the cathode 102 and anode 104, respectively. In examples, the cathode 102 further includes screw hole 122 used in a partial assembly step of the battery 100. In an expanded battery chamber 114A, a carbon black 102B layer of the cathode 102 and a cathode coating 102A is shown, with a separator and electrolyte 124 disposed between the anode 104. The spring 116 holds and maintains contact between the layers shown in the battery chamber 114A. FIG. IB shows an additional enlarged view of battery chamber 126 showing a diffusion of carbon dioxide gas 128 through the cathode 102 side of the battery 100. Also shown within the separator / electrolyte 124 layer is the reaction of an aluminum anode 104 composition, as well as a charging path 130 of the battery 100 and a discharging path 132 of the battery 100.

[0028] FIGS. 2A and 2B are plots depicting voltage vs. capacity and current vs voltage for devices of the present disclosure. FIG. 2A is a plot of voltage (V) vs. capacity (mAh / g) for batteries including an addition of aluminum iodide into the electrolyte, which enables reversibility of the charging. This is shown for compositions of 1.3 AlC13 / [l-Ethyl-3-methylimidazolium chloride ([EMIM]C1) + CO2, 0.05 M A1I3- 1.3 A1C13 / [EMIM]C1, and 1.3 AlCl3 / [l-Ethyl-3- methylimidazolium chloride ([EMIM]C1) + CO2The A1I3allows for battery reversibility via a CO2reduction reaction.

[0029] FIGS. 3A and 3B depict several battery configurations showing different locations of cathode coatings, and a plot of current vs. voltage demonstrating the effect, respectively, in accordance with the present disclosure. In a battery with a first orientation 300, where a cathode coating 306 is in direct contact with the separator / electrolyte 308, the battery orientation 300 further comprises a cathode including a carbon paper 304 layer and cathode coating 306, an anode 310, comprised of, for example, aluminum, and a separator / electrolyte 308 disposed therebetween. A spring 312 is compressed against an outer surface of the cathode, pressing the layers of the carbon paper 304 layer and cathode coating 306 against the separator / electrolyte 308. In this first orientation 300, carbon dioxide flow introduced into the battery or electrochemical cell, produces carbon dioxide flow across, or parallel to the surface of the cathode 314 in this first orientation 300. In a battery having a second orientation 302, a cathode includes a cathode having a carbon paper 304 layer and cathode coating 306, where the cathode coating 306 is facing away from and not in direct contact with a separator / electrolyte 308 that is disposed between the cathode and an anode 310. A spring 312 is compressed against an outer surface of the cathode, pressing the layers of the carbon paper 304 layer and cathode coating 306 against the separator / electrolyte 308. In this second orientation 302, carbon dioxide flow introduced into the battery or electrochemical cell, produces carbon dioxide flow perpendicular to the surface of the cathode 316. The separator / electrolyte 308 includes materials known in the art as a separator, and imidazolium-based ionic liquid electrolyte materials.

[0030] The use of functional carbon-based materials having increased surface area, heteroatom doping and unique pore structure as the cathode, can influence the behavior of a rechargeable Al- CO2 battery, which can enhance CO2 reduction during the discharge processes, thereby improving reaction kinetics. For example, higher surface area and / or porous materials facilitate faster electron transfer during the electrochemical reactions while allowing better CO2 diffusion into the cathode, improving reaction rates. This is shown in FIG. 3B, where a larger magnitude of current can be realized when a first orientation 300 where the cathode coating, comprising the higher surface area and porous materials is in closer, or direct contact with the electrolyte, as noted by the dotted line in FIG. 3B, as compared to the data represented by the solid line, which shows the performance of the second orientation 302, where the cathode coating 306 is facing away from and not in direct contact with a separator / electrolyte 308 that is disposed between the cathode and an anode 310. Without being bound by any particular theory, it is hypothesized that in an exemplary aluminum / carbon dioxide (CO2) battery system, a higher surface area and porous materials facilitate faster electron transfer during the electrochemical reactions while allowing improved CO2 diffusion into the cathode, improving reaction rates. An example cathode material used in an aluminum / CCh battery can include a mixture of Ketjenblack carbon black and polyvinylidene fluoride with a ratio of 2: 1 coated on a Toray Carbon Paper 030, Wet Proofed. Ketjenblack is an amorphous carbon black product and the morphology network of this material plays a role in the reduction of CO2 acting as a catalyst and also as a cathode.

[0031] Another exemplary material being evaluated is a combination of Ketjenblack carbon black mixed with graphene and polyvinylidene fluoride (PVDF) in a ratio of 2:2: 1 coated on a Toray Carbon Paper 030, Wet Proofed. This material increases the conductivity of the cathode material allowing the battery to have higher current densities and better cycle stability during the charge and discharge. The same 2:2: 1 ratio of Ketjenblack:graphene:PVDF was coated on both sides of the Toray Carbon Paper 030, Wet proofed. This setup enhances the kinetics of the cathode active material increasing the current density about three times more than the initial setup and also increasing the cyclability of the battery from seven to fifteen cycles.

[0032] FIG. 4 is a plot of current vs. voltage of a battery having improved current density and cyclability, in accordance with the present disclosure. The various cathode coatings shown below in Table 1 are described therein and shown in the plot of FIG. 4, indicating maximum charge peak, maximum discharge peak, and max number of cycles for each example material.

[0033] FIGS. 5A and 5B are magnified images of carbon fiber coated with carbon black, and carbon fiber coated with carbon black and graphene, respectively, in accordance with the present disclosure. As shown in the micrographs of FIGS. 5A and 5B, the carbon fiber coated with both ketjenblack carbon black and graphene shows increased porosity and higher surface energy in the composition shown in FIG. 5B as compared to the composition of the image of FIG. 5A, which includes a carbon fiber coated with only ketjenblack carbon black.

[0034] The present disclosure provides batteries or electrochemical cells including an anode, comprising a metal, a cathode, comprising a hydrophobic paper, and an electrolyte separating the anode and the cathode, and wherein the hydrophobic paper comprises a coating on a surface of the hydrophobic paper, and the battery uses carbon dioxide gas as an active cathode material. The coating on the surface of the hydrophobic paper can have a material having a high porosity and a high surface area, such as an electroconductive, or electrically conductive material, such as, but not limited to carbon black, like a ketjenblack carbon black, graphene, and the like.

[0035] In examples, the hydrophobic paper comprises carbon fiber, and the coating on the surface of the hydrophobic paper faces towards the electrolyte, or alternatively, away from the electrolyte. In examples, the metal or anode can include aluminum or alloys thereof. Such a battery is configured to operate reversibly while charging and discharging. The battery, and in particular the electrolyte material can include aluminum iodide, AICT / | l -Ethyl-3-mcthylimidazoliiim chloride ([EMIM]C1).

[0036] In an exemplary battery assembly, the battery assembly includes a battery chamber, that includes a metal anode, a cathode, including a hydrophobic paper coated on a surface, and an electrolyte separating the anode and the cathode, wherein the battery uses carbon dioxide gas as an active cathode material, an inlet port in communication with the battery chamber configured to introduce carbon dioxide gas into the battery chamber, and a spring-actuated outlet port configured to relieve pressure within the battery chamber.

[0037] As shown herein, the examples described herein provide an aluminum / CCE battery set up allowing CO2 gas as an active cathode material. Furthermore, the inclusion of aluminum iodide (Alls) allows for battery reversibility via CO2 reduction reactions. The use of hydrophobic paperdecreases current density due to decreased electrode / electrolyte contact, and the addition of graphene to ketjenblack coating improves cyclability and kinetics of battery operation and performance.

[0038] While the present teachings have been illustrated with respect to one or more implementations, alterations and / or modifications may be made to the illustrated examples without departing from the spirit and scope of the appended claims. For example, it may be appreciated that while the process is described as a series of acts or events, the present teachings are not limited by the ordering of such acts or events. Some acts may occur in different orders and / or concurrently with other acts or events apart from those described herein. Also, not all process stages may be required to implement a methodology in accordance with one or more aspects or embodiments of the present teachings. It may be appreciated that structural objects and / or processing stages may be added, or existing structural objects and / or processing stages may be removed or modified. Further, one or more of the acts depicted herein may be carried out in one or more separate acts and / or phases. Furthermore, to the extent that the terms “including,” “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” The term “at least one of’ is used to mean one or more of the listed items may be selected. Further, in the discussion and claims herein, the term “on” used with respect to two materials, one “on” the other, means at least some contact between the materials, while “over” means the materials are in proximity, but possibly with one or more additional intervening materials such that contact is possible but not required. Neither “on” nor “over” implies any directionality as used herein. The term “conformal” describes a coating material in which angles of the underlying material are preserved by the conformal material. The term “about” indicates that the value listed may be somewhat altered, as long as the alteration does not result in nonconformance of the process or structure to the illustrated embodiment. The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with” or “in connection with via one or more intermediate elements or members.” Finally, the terms “exemplary” or “illustrative” indicate the description is used as an example, rather than implying that it is an ideal. Other embodiments of the present teachings may be apparent to those skilled in the art from consideration of the specification and practice of the disclosure herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the present teachings being indicated by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A batery, comprising: an anode, comprising a metal; a cathode, comprising a hydrophobic paper; and an electrolyte separating the anode and the cathode; and wherein: the hydrophobic paper comprises a coating on a surface of the hydrophobic paper; and the batery uses carbon dioxide gas as an active cathode material.

2. The batery of claim 1, wherein the coating on the surface of the hydrophobic paper comprises a high porosity and a high surface area.

3. The batery of claim 1, wherein the coating on the surface of the hydrophobic paper comprises an electroconductive carbon black.

4. The batery of claim 1, wherein the coating on the surface of the hydrophobic paper comprises graphene.

5. The batery of claim 1, wherein the hydrophobic paper comprises carbon fiber.

6. The batery of claim 1, wherein the coating on the surface of the hydrophobic paper faces towards the electrolyte.

7. The batery of claim 1, wherein the coating on the surface of the hydrophobic paper faces away from the electrolyte.

8. The batery of claim 1, wherein the metal comprises aluminum.

9. The batery of claim 1, wherein the batery is configured to operate reversibly while charging and discharging.

10. The batery of claim 1, wherein the batery further comprises aluminum iodide.

11. A batery assembly, comprising: a batery chamber, comprising: an anode, comprising a metal;a cathode, comprising a hydrophobic paper coated on a surface; and an electrolyte separating the anode and the cathode; and wherein the battery uses carbon dioxide gas as an active cathode material; an inlet port in communication with the battery chamber configured to introduce carbon dioxide gas into the battery chamber; and a spring-actuated outlet port configured to relieve pressure within the battery chamber.

12. The battery assembly of claim 11, wherein the coating on the surface of the hydrophobic paper comprises an electroconductive carbon black.

13. The battery assembly of claim 11, wherein the coating on the surface of the hydrophobic paper comprises graphene.

14. The battery assembly of claim 11, wherein the hydrophobic paper comprises carbon fiber.

15. The battery assembly of claim 11, wherein the coating on the surface of the hydrophobic paper faces towards the electrolyte.

16. The battery assembly of claim 11, wherein the coating on the surface of the hydrophobic paper faces away from the electrolyte.

17. The battery assembly of claim 11, wherein the metal comprises aluminum.

18. The battery assembly of claim 11, wherein the battery is configured to operate reversibly while charging and discharging.

19. The battery assembly of claim 11, wherein the battery further comprises aluminum iodide.

20. A battery, comprising: an anode, comprising aluminum; a cathode, comprising a hydrophobic paper comprising carbon fiber coated on a surface with a coating comprising electroconductive carbon black and graphene; and an electrolyte separating the anode and the cathode; and wherein: the coating on the surface of the hydrophobic paper faces towards the electrolyte; and the battery uses carbon dioxide gas as an active cathode material.

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