Liquid cathode formulation for rechargeable metal halide batteries

Abstract

Rechargeable metal halide batteries with optimized active catholyte solutions have high energy density and do not require charging after manufacture. The optimized active catholyte solutions comprise (i) a mixture of metal halides and their corresponding halogens dissolved in an organic solvent at a concentration ratio greater than 0.5 and (ii) an oxidizing gas. The organic solvent is a nitrile-based compound and / or a heterocyclic compound. Ethylene glycol dimethyl ether can be added to the organic solvent to improve battery performance.

Description

Technical Field

[0001] This invention generally relates to rechargeable batteries, and more specifically, to active cathode electrolyte formulations for rechargeable metal halide batteries. Background Technology

[0002] Rechargeable batteries are in high demand across a wide range of applications, from small batteries for industrial and medical devices to large batteries for electric vehicles and grid energy storage systems. Each application requires a range of electrochemical properties, but battery performance remains a limiting factor in meeting high consumer standards today.

[0003] There are currently two types of rechargeable batteries: batteries that operate through the electrochemical insertion / extraction of ions, such as lithium-ion batteries; and batteries that operate through the conversion reaction of active electrode / electrolyte materials, such as nickel metal hydride (NiMH) batteries. The most well-known and widely used rechargeable battery is the lithium-ion battery, which uses intercalated lithium compounds as electrode materials, allowing lithium ions to move back and forth in the electrolyte pool. NiMH batteries use nickel hydroxide as the positive electrode, a hydrogen-absorbing alloy as the negative electrode, and an alkaline electrolyte (such as potassium hydroxide).

[0004] The drawbacks of lithium-ion and NiMH batteries have hindered their use in a wider range of applications. These drawbacks include slow charging speeds and the high cost of heavy metal cathode materials required to manufacture the batteries. Summary of the Invention

[0005] The present invention overcomes the shortcomings in the art by providing a rechargeable metal halide battery with an optimized active cathode electrolyte solution.

[0006] In one embodiment, the present invention relates to a battery comprising: an anode; a cathode current collector; and an electrolyte for facilitating ion transport between the anode and the cathode current collector, wherein the electrolyte comprises: a solvent containing one or more organic liquid compounds, an active cathode material comprising a mixture of metal halides and their respective halogens, wherein the molar concentration ratio of the metal halide to the halogen is greater than 0.5, the mixture is dissolved in the solvent, the active cathode material is in contact with the cathode current collector, and an oxidizing gas dissolved in the solvent.

[0007] In another embodiment, the present invention relates to an electrolyte for a rechargeable metal halide battery, comprising: a solvent containing one or more organic liquid compounds, an active cathode material comprising a mixture of metal halides and their respective halogens, wherein the molar concentration ratio of the metal halide to the halogen is greater than 0.5, the mixture is dissolved in the solvent, the active cathode material is in contact with a cathode current collector, and an oxidizing gas dissolved in the solvent.

[0008] In other embodiments, the present invention relates to a rechargeable battery comprising: an anode; a cathode current collector; and an electrolyte for facilitating ion transport between the anode and the cathode current collector, wherein the electrolyte comprises: a mixed solvent solution containing a nitrile-based compound and / or a heterocyclic compound; an active cathode material containing a mixture of lithium iodide (LiI) and iodine (I2), wherein the mixture is dissolved in the mixed solvent solution, the molar ratio of LiI to I2 being 0.5 to 8; the active cathode material being in contact with the cathode current collector; and an oxidizing gas dissolved in the solvent.

[0009] In other respects, the present invention relates to a method for preparing an electrolyte for a metal halide rechargeable battery, the method comprising: dissolving a mixture of a metal halide and its corresponding halogen in a solvent comprising a nitrile-based compound and / or a heterocyclic compound, wherein the molar concentration ratio of the metal halide to the halogen is greater than 0.5; and introducing an oxidizing gas into the mixed solvent.

[0010] In another aspect, the present invention relates to a method for manufacturing a metal halide rechargeable battery, the method comprising: dissolving a mixture of LiI and I2 in a solvent to form an electrolyte solution, wherein the solvent comprises a nitrile-based compound and / or a heterocyclic compound, and the molar concentration ratio of LiI to I2 is 0.5 to 8; forming an immersed membrane by immersing a membrane in the electrolyte solution; forming a stack comprising an anode, the immersed membrane, and a cathode current collector, wherein the immersed membrane is placed between the anode and the cathode current collector; and introducing an oxidizing gas into the stack.

[0011] In other respects, the present invention relates to a method for preparing an electrolyte for a metal halide rechargeable battery, the method comprising: combining a metal halide, a corresponding halogen of the metal halide, an oxidizing gas, and a solvent, wherein the solvent comprises a nitrile-based compound and / or a heterocyclic-based compound, and the molar concentration ratio of the metal halide to the halogen is greater than 0.5.

[0012] In another aspect, the present invention relates to a method for manufacturing a metal halide rechargeable battery, the method comprising: forming an electrolyte solution comprising LiI, I2, an oxidizing gas and a solvent, wherein the solvent comprises a nitrile-based compound and / or a heterocyclic compound, and the molar concentration ratio of LiI to I2 is 0.5 to 8; immersing a separator in the electrolyte solution; and forming a stack comprising an anode, an immersed separator and a cathode current collector, wherein the immersed separator is placed between the anode and the cathode current collector.

[0013] In other embodiments and aspects, the metal halide comprises dissociation into (i) selected from I - ,Br - Cl - and F -The ions and (ii) are selected from Li + Mg 2+ Al 3+ and Na + Salts of ions.

[0014] In other embodiments and aspects, the halogen is a molecular halogen including at least one of I2, Br2, Cl2 and F2.

[0015] In other implementations and aspects, the molar concentration ratio of metal halide to halogen is greater than 0.5.

[0016] In other implementations and aspects, the molar concentration ratio of metal halide to halogen is 0.5 to 8.

[0017] In other embodiments and aspects, the organic liquid compound / solvent comprises nitrile-based compounds and / or heterocyclic-based compounds.

[0018] In other embodiments and aspects, the nitrile-based compound is methoxypropionitrile (MPN).

[0019] In other embodiments and aspects, the heterocyclic compound is 1,3-dioxolane (DOL).

[0020] In other embodiments and aspects, the organic liquid compound / solvent also includes a compound based on ethylene glycol dimethyl ether.

[0021] In other embodiments and aspects, the compound based on ethylene glycol dimethyl ether is 1,2-dimethoxyethane (DME).

[0022] In other embodiments and aspects, the oxidizing gas is selected from oxygen, air, nitric oxide, nitrogen dioxide, and mixtures and combinations thereof.

[0023] In other embodiments and aspects, the electrolyte comprises other lithium salts selected from lithium nitrate (LiNO3), lithium fluoride (LiF), lithium bis(trifluoromethanesulfonyl)imide (LiTFSl; LiC2F6NO4S2), lithium trifluoromethanesulfonate (LiCF3SO3), lithium hexafluorophosphate (LiPF6), lithium hexafluoroarsenate (LiAsF6), lithium perchlorate (LiClO4), and lithium tetrafluoroborate (LiBF4).

[0024] In other embodiments and aspects, the anode comprises one or more alkali metals and / or one or more alkaline earth metals.

[0025] In other embodiments and aspects, the anode includes at least one of Li, Mg, Al and Na.

[0026] In other embodiments and aspects, the cathode current collector includes porous carbon materials and / or metals.

[0027] In other implementations and aspects, the porous carbon material is selected from carbon cloth, carbon nanoparticles, polymer binders, and combinations thereof.

[0028] In other implementations and aspects, the metal is selected from stainless steel, copper, nickel, titanium, aluminum, and combinations and alloys thereof.

[0029] Other embodiments and aspects of the invention will be provided in the specific embodiments set forth below, but are not limited thereto. Attached Figure Description

[0030] Figures 1A to 1C This is a comparison curve of the battery capacity after 10 cycles of a battery with an effective LiI (lithium iodide) concentration of 3M in a fully discharged state, under the following operating electrolyte (prepared in a 1:1 solvent mixture of MPN:DME (methoxypropionitrile: 1,2-dimethoxyethane)) and operating conditions: based solely on the LiI electrolyte solution ( Figure 1A ); LiI + iodine (I2) electrolyte solution used as the first cycle for charging cycle operation ( Figure 1B ); and the LiI+I2 electrolyte solution with the first cycle as the discharge cycle ( Figure 1C ).

[0031] Figure 2 This graph compares the battery charging capacity (dashed line) and discharging capacity (solid line) of five different electrolyte solutions prepared in a solvent mixture of 1:1 DOL:DME (1,3-dioxolane:methoxypropionitrile) with different mixtures of LiI and I2 after 400 cycles. Detailed Implementation

[0032] The following is a description of the preferred embodiment of the invention currently considered to be protected. Any substitutions or modifications in function, purpose, or structure shall be included in the appended claims. As used in this specification and the appended claims, unless the context clearly specifies otherwise, no quantifier precedes an element to include the plural case. The term "comprising" as used in the specification and the appended claims specifies the presence of a expressly listed component, element, feature, and / or step, but does not exclude the presence or addition of one or more other components, elements, and / or steps.

[0033] As used in this article, the term "anode" refers to the negative or reducing electrode of a battery that releases electrons from an external circuit and is oxidized during an electrochemical process.

[0034] As used in this article, the term "cathode" refers to the positive or oxidizing electrode of a battery that receives electrons from an external circuit and is reduced in an electrochemical process.

[0035] As used herein, the term "electrolyte" refers to the material that facilitates ion transport between the anode and cathode of a battery. The electrolyte acts as a catalyst for battery conductivity through its interaction with both the anode and cathode. During battery charging, the electrolyte promotes the movement of ions from the cathode to the anode, while during discharging, it promotes the movement of ions from the anode to the cathode.

[0036] As used herein, the term "oxidizing gas" refers to a gas that initiates a reduction-oxidation (redox) reaction in a redox cell. Examples of oxidizing gases include, but are not limited to, oxygen, air, nitric oxide, and nitrogen dioxide. As those skilled in the art will recognize, a redox reaction is a reaction in which electrons are transferred between (i) a reducing agent undergoing oxidation through electron loss and (ii) an oxidizing agent undergoing reduction through electron gain. A redox cell is a rechargeable electrochemical cell in which chemical energy is provided by two electrolytes separated by an ion-exchange membrane. In operation, ion exchange occurs through the ion-exchange membrane along with the flow of current, while the electrolytes circulate in their respective spaces.

[0037] As used herein, the term "metal halide" refers to a compound having both a metal and a halogen. The metal in a metal halide typically includes any metal from Groups 1 through 16 of the periodic table, but is usually an alkali metal from Group 1. The halide of a metal halide will be any halogen from Group 17 of the periodic table.

[0038] As used herein, the terms "nitrile" and "nitrile-based compound" refer to organic chemical substances containing at least one cyano functional group, wherein the carbon and nitrogen atoms are triple-bonded, i.e., C≡N. Examples of nitriles include, but are not limited to, acetonitrile, acrylonitrile, propionitrile, methoxyacetonitrile, methoxypropionitrile (MPN), propylnitrile, cyclopentadienylnitrile, 4-cyanobenzaldehyde, and ethylene glycol bis(propionitrile) ether (EGBP). Like ethylene glycol dimethyl ether, nitriles are chemically inert aprotic polar solvents.

[0039] As used herein, the term "heterocyclic compound" conventionally refers to a cyclic compound having at least two different elements as its ring members. As is known to those skilled in the art, there are too many types of heterocyclic compounds to list; therefore, for the purposes of this disclosure, the following list provides three examples of saturated and unsaturated heterocyclic compounds having nitrogen, oxygen, and sulfur as heteroatoms. It should be understood that this list of heterocyclic compounds is intended to be exemplary and not limiting. Examples of saturated 3-atom rings include, but are not limited to, azirropropane, ethylene oxide, and thioheteropropane. Examples of unsaturated 3-atom rings include, but are not limited to, azirropropene, oxacyclopropene, and thioheteropropene. Examples of saturated 4-atom rings include, but are not limited to, azirrobutane, oxacyclobutane, and thioheterobutane. Examples of unsaturated 4-atom rings include, but are not limited to, azirrobutadiene, oxacyclobutene, and thioheterobutene. Examples of saturated 5-atom rings include, but are not limited to, pyrrolidine, oxacyclopentane, and thioheteropentane. Examples of unsaturated 5-atom rings include, but are not limited to, pyrrole, furan, and thiophene. Examples of saturated 6-atom rings include, but are not limited to, piperidine, oxane, and thiaran. Examples of unsaturated 6-atom rings include, but are not limited to, pyridine, pyran, and thiaran. Examples of saturated 7-atom rings include, but are not limited to, azirheptan, oxeheptane, and thioheptanane. Examples of unsaturated 7-atom rings include, but are not limited to, azirhepene, oxeheptene, and thiohepene. Examples of saturated 8-atom rings include, but are not limited to, azirheptan, oxeheptane, and thioheptanane. Examples of unsaturated 8-atom rings include, but are not limited to, azirhepene, oxeheptene, and thioheptanene. Examples of saturated 9-atom rings include, but are not limited to, azirheptan nonane, oxeheptene, and thioheptan nonane. Examples of unsaturated 9-atom rings include, but are not limited to, azirheptan nonene, oxeheptene, and thioheptan nonene. An exemplary but non-limiting heterocycle used herein is 1,3-dioxolane (DOL).

[0040] Metal halide batteries are redox batteries that use metal halides as the active cathode material in the presence of an oxidizing gas. Unlike lithium-ion and NiMH batteries, metal halide batteries are not manufactured using heavy metals; therefore, they have a potentially lower manufacturing cost than conventional lithium-ion or NiMH batteries. To become a suitable alternative to lithium-ion and NiMH batteries, metal halide batteries need to be optimized.

[0041] As used herein, the terms "ethylene glycol dimethyl ether" and "ethylene glycol dimethyl ether-based compounds" refer to ethylene glycol ether solvents that do not carry free hydroxyl groups. Due to the lack of functional groups, ethylene glycol dimethyl ether solvents are chemically inert and aprotic (lacking H atoms / cannot form hydrogen bonds) polar solvents. The general chemical formula for ethylene glycol dimethyl ethers is: R 1 O-(CR 2 2CR 2 2O)n-CR1 Examples of ethylene glycol dimethyl ether solvents include, but are not limited to, 1,2-dimethoxyethane, 1,2-diethoxyethane, 2-methoxyethyl ether (diethylene glycol dimethyl ether), 1,2-bis(2-methoxyethoxy)ethane (triethylene glycol dimethyl ether), and bis[2-(2-methoxyethoxy)ethyl] ether (tetraethylene glycol dimethyl ether).

[0042] This article describes a battery comprising an anode, an electrolyte, and a cathode current collector in contact with an active cathode material, wherein the electrolyte comprises (i) a solvent containing one or more organic liquid compounds; (ii) a mixture of metal halides and their respective halogens, wherein the mixture is used as the active cathode material and is dissolved in the solvent; and (iii) an oxidizing gas also dissolved in the solvent.

[0043] In one embodiment, the metal halide and its corresponding halogen are dissolved in a solvent before the oxidizing gas is introduced. In another embodiment, the metal halide, its corresponding halogen, and the oxidizing gas are introduced into the solvent together. In yet another embodiment, the metal halide, its corresponding halogen, the oxidizing gas, and the solvent are combined to form an electrolyte solution.

[0044] Solvents that can be used to prepare the electrolyte formulations described herein include, but are not limited to, nitriles, heterocyclic compounds, and ethylene glycol dimethyl ether. In one embodiment, the solvent includes nitriles and ethylene glycol dimethyl ether. In another embodiment, the solvent includes a heterocyclic compound having ethylene glycol dimethyl ether. In yet another embodiment, the solvent includes nitriles and heterocyclic compounds. In yet another embodiment, the solvent includes nitriles, heterocyclic compounds, and ethylene glycol dimethyl ether.

[0045] Metal halides that can be used to prepare the electrolyte formulations described herein include any metal halide, which includes salts that can dissociate into: (i) selected from I - ,Br - Cl - and F - (ii) ions selected from Li + Mg 2+ Al 3+ and Na + The ions. The halogen can be any molecular halogen containing at least one of I2, Br2, Cl2, and F2. In one embodiment, the molar concentration ratio of the metal halide to the halogen is greater than 0.5. In another embodiment, the molar concentration ratio is from 0.5 to 8. In other embodiments, the molar concentration ratio is about 1. For illustrative purposes only and not intended to be limiting, the metal halide LiI and the halogen I2 will be described herein as an exemplary mixture of active cathode materials.

[0046] Oxidizing gases that can be used in electrolytes include, but are not limited to, oxygen, air, nitric oxide, nitrogen dioxide, and mixtures and combinations thereof.

[0047] In another embodiment, the electrolyte may include one or more lithium salts (in addition to LiI). Examples of other lithium salts include, but are not limited to, lithium nitrate (LiNO3), lithium fluoride (LiF), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI; LiC2F6NO4S2), lithium trifluoromethanesulfonate (LiCF3SO3), lithium hexafluorophosphate (LiPF6), lithium hexafluoroarsenate (LiAsF6), lithium perchlorate (LiClO4), and lithium tetrafluoroborate (LiBF4).

[0048] Examples of materials that can be used as the anode of the rechargeable battery described herein include, but are not limited to, one or more alkali metals and / or one or more alkaline earth metals. In one embodiment, the anode comprises at least one of Li, Mg, Al, and Na.

[0049] Examples of materials used in cathode current collectors for rechargeable batteries include, but are not limited to, porous carbon materials and compatible metals. Examples of porous carbon materials include, but are not limited to, carbon cloth, carbon nanoparticles, polymer binders, and combinations thereof. Examples of compatible metals include, but are not limited to, stainless steel, copper, nickel, titanium, aluminum, and combinations thereof and alloys thereof.

[0050] As those skilled in the art will understand, the batteries described herein are intended to be manufactured and sold as battery assemblies. Examples of such battery assemblies include, but are not limited to, pouch cells, cylindrical cells, prismatic cells, coin cells, and Swagelok cells. (RTM) Battery (SWAGELOK Corporation, Solon, OH, USA).

[0051] The liquid active cathode material described in this paper increases the solubility of metal halides without significantly increasing electrolyte viscosity, thereby resulting in a metal halide battery with improved energy density compared to conventional metal halide batteries. This high energy density of the metal halide battery is achieved through an active cathode material formulation comprising a mixture of metal halides and their corresponding halogens in the presence of an oxidizing gas. The combination of molecular halogens and metal halides as active cathode materials reduces the manufacturing cost of the high-energy-density metal halide battery described in this paper because molecular halogens are less expensive than metal halide salts.

[0052] Example 1 describes the general steps for preparing a battery using an active cathode electrolyte solution comprising (i) a mixed solvent solution of nitrile, methoxypropionitrile (MPN) and ethylene glycol dimethyl ether, 1,2-dimethoxyethane (DME) in a 1:1 volume ratio, and (ii) LiI or LiI+I2 as the active cathode material. Figures 1A to 1C Table 1 shows the discharge capacity performance of three metal halide batteries manufactured according to the method in Example 1 after ten cycles, wherein the effective molar concentration of the active cathode material and the discharge conditions are as follows: only 3M LiI ( Figure 1A ); 1M LiI + 1M I2 first cycle charge ( Figure 1B ); and the first cycle discharge of 1M LiI + 1M I2 ( Figure 1C ). Figure 1B and Figure 1C It also includes the discharge conditions used for testing, wherein Figure 1B The discharge capacity performance of the battery after it has been charged following manufacturing is shown. Figure 1C The discharge capacity performance of the batteries after manufacturing, without initial charging, is shown. All batteries are at 1 mA / cm². 2 The test was conducted at current density. For example... Figures 1A to 1C As shown in Table 1, the battery made with Li+I2 active cathode material performs better than the battery made with LiI alone. The data also indicate that when the first cycle is a discharge cycle, the battery made with LiI+I2 active cathode material performs better after ten cycles (5.67 mA-hr / cm). 2 The reading showed a higher efficiency than the initial charge cycle (4.71 mA-hr / cm). 2 Higher discharge capacity. These data indicate that, unlike conventional metal halide batteries, batteries made using active cathode formulations containing metal halides and their corresponding molecular halogens can discharge immediately after manufacturing without requiring an initial charge cycle.

[0053] Table 1

[0054]

[0055] Example 2 describes the procedure for testing the viscosity of the metal halide / molecular halogen active cathode material described herein in a mixed solvent solution. As shown in Table 2, when LiI is the only active cathode material in the organic electrolyte solution, the viscosity of the electrolyte solution increases with increasing LiI content (Test 1 and Test 2). When testing the viscosity of a control electrolyte solution containing LiI+I2, the LiI+I2 electrolyte solution exhibits the same viscosity as the LiI-only electrolyte solution (Test 5 and Test 6). The results in Table 2 indicate that introducing the corresponding molecular halogen into the metal halide active cathode electrolyte formulation has no effect on the viscosity of the electrolyte solution. Due to the molecular weight difference between metal halides and molecular halogens, replacing some of the metal halides in the battery with molecular halogens leads to an increase in the amount of active cathode material that can be loaded into the battery during manufacturing. The resulting increase in active cathode material without a corresponding increase in viscosity results in a battery with improved volumetric energy density and increased charge transport kinetics compared to conventional metal halide batteries.

[0056] Table 2

[0057] test# <![CDATA[Iodine (I2, M)]]> Lithium iodide (LiI, M) Viscosity (CP) 1 0 0.5 1.32 2 0 1 2.06 3 0.5 0 0.95 4 1 0 1.07 5 0.5 0.5 1.36 6 1 1 2.06

[0058] Figure 2 The charge / discharge capacities of metal halide batteries fabricated using the following LiI+I2 active cathode formulations after 400 cycles are shown: 0.8M LiI + 0.1M I2; 0.5M LiI + 0.25M I2; 0.33M LiI + 0.33M I2; 0.2M LiI + 0.4M I2; and 1M LiI as a control. Figure 2 As shown, a metal halide battery fabricated using a LiI cathode formulation with equimolar concentrations of LiI and I2 (0.33M LiI + 0.33M I2) maintained the same discharge capacity as the control battery (1M LiI) after 250 cycles. Table 3 provides data based on... Figure 2 The data in Table 3 shows the range of molar concentrations of LiI to I2. As shown in Table 3, the batteries described herein operate at molar concentration ratios of metal halide to halogen ranging from 0.5 to infinity. In the context of the LiI+I2 batteries in Table 3, I2 > 0. More generally, for the metal halide / halogen batteries described herein, the halogen molar concentration can be close to, but not equal to, zero (halogen > 0). Since the commercial cost of metal halide salts is significantly higher than that of molecular halogens, batteries manufactured using active cathode electrolyte formulations containing both metal halides and molecular halogens are more cost-effective than conventional metal halide batteries.

[0059] Table 3

[0060] <![CDATA[Molar concentrations of LiI and I2]]> <![CDATA[LiI / I2]]> 1MLiI ∞ <![CDATA[0.8M LiI+0.1M I2]]> 8 <![CDATA[0.5M LiI+0.25MI2]]> 2 <![CDATA[0.33 M LiI + 0.33 M I2 (pre - charge)]]> 1 <![CDATA[0.33MLiI + 0.33MI2 (pre-discharge)]]> 1 <![CDATA[0.2MLiI+0.4MI2]]> 0.5

[0061] Example 3 describes the process used to test the solubility of the metal halide / molecular halogen active cathode material described herein in a mixed solvent solution. As shown in Table 4, the maximum solubility of LiI alone in a solvent solution with an MNP:DME ratio of 1:1 is 5 M; however, when I2 is added to the solution, the maximum solubility of LiI increases to 7 M, indicating a synergistic effect between LiI and I2 in the mixed solvent electrolyte solution.

[0062] Table 4

[0063]

[0064] Referring to Table 4, the effective iodine ions (I₂) in the battery under fully discharged conditions - Concentration of I - =LiI + 2I₂. When 7MLiI and 3MI₂ are used as active cathode materials, the concentration of iodide ions in the electrolyte is 13MI₂ under fully discharged conditions. - The effective iodide ion concentration is more than twice that obtained by batteries with only LiI or I2 active cathode materials. The intermediate product of the reaction between 7M LiI and 3M I2 is 3M triiodide ions (I3). - (; charging products) and 4M I - (Discharge products). The chemicals that contribute to the high discharge capacity of metal halide batteries are the charge products in the electrolyte solution (i.e., I3). - Therefore, for batteries manufactured with an optimized concentration of LiI+I2 in the electrolyte solution, the presence of I3 in the electrolyte solution is crucial. - The presence of ions means the battery does not need to be charged before use. The results in Table 4 indicate that preparing electrolyte solutions in organic solvents using stoichiometric amounts of metal halides and their corresponding halogens allows for optimization of the solubility of chemicals in the electrolyte that contribute to discharge capacity.

[0065] The metal halide / molecular halogen active cathode electrolyte material described in this article has the following improvements compared to conventional metal halide batteries: lower manufacturing cost, higher load capacity, higher energy density, higher charge transport kinetics, and the ability to discharge immediately after manufacturing.

[0066] For illustrative purposes, various embodiments of the invention have been described, but are not intended to be exhaustive or limiting. Many modifications and variations will be apparent to those skilled in the art without departing from the scope of the described embodiments. The terminology used herein has been chosen to best explain the principles of the embodiments, practical applications of techniques found in the market, or technical improvements, or to enable those skilled in the art to understand the embodiments disclosed herein.

[0067] experiment

[0068] The following embodiments are described to provide a complete disclosure to those skilled in the art on how to manufacture and use the aspects and embodiments of the invention set forth herein. While efforts have been made to ensure the accuracy of variables (such as amounts, temperatures, etc.), experimental errors and biases should be taken into account. Unless otherwise stated, parts are parts by weight, temperatures are in degrees Celsius, and pressures are at or near atmospheric pressure. Unless otherwise stated, all components are commercially available.

[0069] Example 1

[0070] General steps in battery fabrication

[0071] Batteries were fabricated using LiI and I2 as active cathode materials. LiI was placed in vials and dried on a hot plate at 120°C in an argon-filled glove box (<0.1 ppm H2O, O2) for 12 hours. I2 was used in its condition upon arrival. A compound based on ethylene glycol dimethyl ether (DME), a compound based on nitrile (MPN), and a heterocyclic compound (1,3-dioxolane) were mixed with 20 mg of molecular sieve. The cells were stored overnight in separate vials. Then, mixed solvent solutions were prepared at a 1:1 volume ratio using the following compounds: (i) DME and MPN, and (ii) DME and 1,3-dioxolane. For testing, individual LiI, individual I2, or a mixture of LiI and I2 were dissolved in the mixed solvent solution at predetermined molar ratios to form active cathode electrolyte solutions. Each electrolyte solution was then used to wet a quartz filter separator and a cathode current collector, which consisted of carbon cloth, carbon nanoparticles, and a polymer binder. The active cathode material was kept in constant contact with the carbon cathode current collector and the electrolyte solution. All battery assembly was performed in a glove box. The lithium metal foil anode, the electrolyte-wetted separator, and the wetted carbon current collector were placed sequentially inside a Swagelok-type battery equipped with an oxygen inlet and outlet pipe. Oxygen was introduced from the inlet pipe, purging and completely replacing the argon gas within the battery.

[0072] Example 2

[0073] The effect of iodine-active material formulations on electrolyte viscosity

[0074] Following the battery manufacturing steps of Example 1, the viscosities of six different liquid cathode formulations were tested. As shown in Table 2, the following six mixtures of LiI, I2, and LiI+I2 were prepared in 30 mL of a 1:1 MPN:DME (v / v) solvent mixture: (1) 0.5 M I2; (2) 1 M I2; (3) 0.5 M LiI; (4) 1 M LiI; (5) 0.5 M I2 + 0.5 M LiI; and (6) 1 M I2 + 1 M LiI. SEKONIC was used. (RTM)The VM-100A-L torsional vibration meter (Kabushiki Kaisha Sekonic, Tokyo, JP) measured the viscosity of the solution in six tests.

[0075] Example 3

[0076] The effect of iodine-active material formulations on total mass load

[0077] A 50:50 MPN:DME (v / v) mixed solvent solution was prepared as described in Example 1 and separated into three 1 mL volumes. To test the solubility of the active cathode materials, the following three active cathode materials were added to three 1 mL volumes of the mixed solvent solution: 5 mM LiI; 3 mM I2; and 7 mM LiI + 3 mM I2. Table 4 shows the results of the solubility test.

Claims

1. A battery comprising: an anode; a cathode current collector; and an electrolyte that facilitates the transport of ions between the anode and the cathode, wherein the electrolyte comprises: a solvent comprising one or more organic liquid compounds, an active cathode material comprising a mixture of a metal halide and its corresponding halogen, wherein the molar concentration ratio of the metal halide to the halogen is 1 to 2, the mixture is dissolved in the solvent, and the active cathode material is in contact with the cathode current collector, and an oxidizing gas dissolved in the solvent.

2. The battery of claim 1, wherein the metal halide comprises a salt that dissociates into (i) an ion selected from the group consisting of I - , Br - , Cl - , and F - and (ii) an ion selected from the group consisting of Li + , Mg 2+ , Al 3+ , and Na + .

3. The battery of claim 1, wherein the halogen is a molecular halogen comprising at least one of I2, Br2, Cl2, and F2.

4. The battery of claim 1, wherein the one or more organic liquid compounds comprise a nitrile and / or a heterocyclic compound.

5. The battery of claim 4, wherein the one or more organic liquid compounds comprise ethylene glycol dimethyl ether.

6. The battery of claim 1, wherein the anode comprises one or more alkali metals and / or one or more alkaline earth metals.

7. The battery of claim 2, wherein the anode comprises at least one of Li, Mg, Al, and Na.

8. The battery of claim 1, wherein the cathode current collector comprises a porous carbon material and / or a metal.

9. The battery of claim 1, wherein the oxidizing gas is selected from the group consisting of oxygen, air, nitric oxide, nitrogen dioxide, and mixtures and combinations thereof.

10. An electrolyte for a rechargeable metal halide battery comprising: a solvent comprising one or more organic liquid compounds, an active cathode material comprising a mixture of a metal halide and its corresponding halogen, wherein the molar concentration ratio of the metal halide to the halogen is 1 to 2, and the mixture is dissolved in the solvent; and an oxidizing gas dissolved in the solvent.

11. The electrolyte of claim 10, wherein the metal halide comprises a salt that dissociates into (i) an ion selected from the group consisting of I - , Br - , Cl - , and F - and (ii) an ion selected from the group consisting of Li + , Mg 2+ , Al 3+ , and Na + .

12. The electrolyte of claim 10, wherein the halogen is a molecular halogen comprising at least one of I2, Br2, Cl2, and F2.

13. The electrolyte of claim 10, wherein the organic solvent comprises a nitrile and / or a heterocyclic compound.

14. The electrolyte of claim 13, wherein the organic liquid compound comprises ethylene glycol dimethyl ether.

15. The electrolyte of claim 10, wherein the oxidizing gas is selected from the group consisting of oxygen, air, nitric oxide, nitrogen dioxide, and mixtures and combinations thereof.

16. A rechargeable battery comprising: an anode; a cathode current collector; and an electrolyte that facilitates the transport of ions between the anode and the cathode current collector, wherein the electrolyte comprises: a mixed solvent solution comprising a nitrile-based compound and / or a heterocyclic-based compound, an active cathode material comprising a mixture of Lil and I2, wherein the mixture is dissolved in the mixed solvent solution, the molar concentration ratio of Lil to I2 is 1 to 2, and the active cathode material is in contact with the cathode current collector, and an oxidizing gas dissolved in the solvent.

17. The rechargeable battery of claim 16, wherein the nitrile-based compound is methoxypropionitrile and the heterocyclic-based compound is 1,3-dioxolane.

18. The rechargeable battery of claim 16, wherein the mixed solvent solution comprises a glyme-based compound.

19. The rechargeable battery of claim 18, wherein the glyme-based compound is 1,2- dimethoxyethane.

20. The rechargeable battery of claim 16, wherein the electrolyte comprises an additional lithium salt selected from the group consisting of lithium nitrate (LiNO3), lithium fluoride (LiF), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI; LiC2F6NO4S2), lithium trifluoromethanesulfonate (LiCF3SO3), lithium hexafluorophosphate (LiPF6), lithium hexafluoroarsenate (LiAsF6), lithium perchlorate (LiClO4), and lithium tetrafluoroborate (LiBF4).

21. The rechargeable battery of claim 16, wherein the anode comprises Li.

22. The rechargeable battery of claim 16, wherein the cathode current collector comprises a porous carbon material and / or a metal.

23. The rechargeable battery of claim 16, wherein the oxidizing gas is selected from the group consisting of oxygen, air, nitric oxide, nitrogen dioxide, and mixtures and combinations thereof.

24. A method of making an electrolyte for a metal halide rechargeable battery, the method comprising: dissolving a metal halide and its corresponding halogen in a solvent comprising a nitrile-based compound and / or a heterocycle-based compound, wherein the molar concentration ratio of the metal halide to the halogen is 1 to 2; and introducing an oxidizing gas into the solvent.

25. The method of claim 24, wherein the metal halide comprises a salt that dissociates into (i) an ion selected from the group consisting of I - , Br - , Cl - , and F - and (ii) an ion selected from the group consisting of Li + , Mg 2+ , Al 3+ , and Na + .

26. The method of claim 24, wherein the halogen is a molecular halogen comprising at least one of I2, Br2, Cl2, and F2.

27. The method of claim 24, wherein the nitrile-based compound is methoxypropionitrile and the heterocycle-based compound is 1,3-dioxolane.

28. The method of claim 24, wherein the mixed solvent solution comprises a glyme-based compound.

29. The method of claim 24, wherein the glyme-based compound is 1,2-dimethoxyethane.

30. The method of claim 24, wherein the oxidizing gas is selected from the group consisting of oxygen, air, nitric oxide, nitrogen dioxide, and mixtures and combinations thereof.

31. A method of manufacturing a metal halide rechargeable battery, the method comprising: dissolving LiI and I2 in a solvent to form an electrolyte solution, wherein the solvent comprises a nitrile-based compound and / or a heterocycle-based compound, and the molar concentration ratio of the LiI to the I2 is 1 to 2; immersing a separator in the electrolyte solution; forming a stack comprising an anode, the immersed separator, and a cathode current collector, wherein the immersed separator is placed between the anode and the cathode current collector; and introducing an oxidizing gas into the stack.

32. The method of claim 31, wherein the nitrile-based compound is methoxypropionitrile and the heterocycle-based compound is 1,3-dioxolane.

33. The method of claim 31, wherein the solvent comprises a glyme-based compound.

34. The method of claim 33, wherein the ethylene glycol dimethyl ether-based compound is 1,2-dimethoxyethane.

35. A method of making an electrolyte for a metal halide rechargeable battery, the method comprising: combining a metal halide, a corresponding halogen of the metal halide, an oxidizing gas, and a solvent, wherein the solvent comprises a nitrile-based compound and / or a heterocycle-based compound, and the molar concentration ratio of the metal halide to the halogen is 1 to 2.

36. A method of manufacturing a metal halide rechargeable battery, the method comprising: forming an electrolyte solution comprising LiI, I2, an oxidizing gas, and a solvent, wherein the solvent comprises a nitrile-based compound and / or a heterocycle-based compound, and the molar concentration ratio of LiI to I2 is 1 to 2; immersing a separator in the electrolyte solution; and forming a stack comprising an anode, the immersed separator, and a cathode current collector, wherein the immersed separator is positioned between the anode and the cathode current collector.

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