Rechargeable metal halide battery including an intercalation anode

Abstract

A metal halide battery includes an intercalation anode, a cathode containing a metal halide incorporated into a conductive material, an oxidizing gas, and an electrolyte in contact with the intercalation anode, the cathode, and the oxidizing gas. At current densities that allow the battery to be charged within 10 to 15 minutes, the battery has a cycle life approaching 1,000 cycles. An electrolyte that can be used in a metal halide battery includes (i) a carbonate ester-based compound having at least one ethyl group and an ionically conductive salt, or (ii) at least one cyclic ester compound, or both.

Description

Technical Field

[0001] The present invention generally relates to rechargeable metal halide batteries, and more particularly to rechargeable metal halide batteries comprising an intercalation anode, an oxidizing gas, and an electrolyte comprising (i) a compound based on a carbonate having at least one ethyl group and an ionic conductive salt or (ii) at least one cyclic ester compound or both.

Background Art

[0002] Rechargeable batteries are in high demand for a wide range of applications, from small batteries for industrial and medical equipment to large batteries for electric vehicles and grid energy storage systems. Currently used rechargeable batteries include two types: (i) batteries that operate by the electrochemical intercalation / deintercalation behavior of active ions, and (ii) batteries that operate by the conversion reaction of active electrode / electrolyte materials. The most well-known and widely used rechargeable battery is the lithium-ion battery, which uses an intercalated lithium compound as one of the electrode materials and has lithium ions that move in and out of a liquid electrolyte. Lithium-ion batteries have drawbacks that need to be overcome to meet the high standards in the market, such as slow charge / discharge rates and high costs of cathode materials. Cathode materials such as lithium nickel manganese cobalt oxide (NMC), lithium nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LCO), and lithium iron phosphate (LFP) have hindered the wider use of lithium-ion batteries. Lithium metal has been widely considered as a preferred active anode material due to its high theoretical energy density. However, problems associated with lithium metal, such as dendrite growth that causes cell short circuits, have hindered the wide commercialization of lithium-ion batteries.

Summary of the Invention

[0003] The present invention meets the needs in this field by using a rechargeable metal halide battery comprising an intercalation anode, an oxidizing gas, and an electrolyte that can include (i) a compound based on a carbonate having at least one ethyl group and an ionic conductive salt or (ii) at least one cyclic ester compound or both.

[0004] In one embodiment, the present invention relates to a battery comprising an intercalation anode, a cathode comprising a metal halide incorporated in a conductive material, an oxidizing gas, and an electrolyte in contact with the intercalation anode, the cathode, and the oxidizing gas.

[0005] In another embodiment, the present invention relates to a battery comprising an intercalation anode, a cathode comprising a metal halide incorporated in a conductive material, an oxidizing gas, and (i) a compound based on a carbonate having at least one ethyl group, and (ii) a metal cation [M] + [X] - having the formula [M] + and an ionic conductive salt comprising an anion [X] - , wherein the electrolyte is in contact with the intercalation anode, the cathode, and the oxidizing gas.

[0006] In a further embodiment, the present invention relates to a battery comprising an intercalation anode, a cathode comprising a metal halide incorporated in a conductive material, an oxidizing gas, and an electrolyte comprising at least one cyclic ester compound, wherein the electrolyte is in contact with the intercalation anode, the cathode, and the oxidizing gas.

[0007] In one aspect, the present invention relates to an intercalation anode, a metal halide cathode in a conductive material, a separator positioned between the intercalation anode and the conductive material of the metal halide cathode, and (i) a compound based on a carbonate having at least one ethyl group, and (ii) a chemical formula [M]+ [X] - has a metal cation [M] + and an anion [X] - A method of forming a battery, comprising forming a battery stack comprising an electrolyte comprising an ionic conductive salt containing a metal cation [M] having [X] and an anion [X], wherein an oxidizing gas is introduced into the battery stack, and the electrolyte is in contact with an intercalation anode, a metal halide cathode, and the oxidizing gas.

[0008] In another aspect, the present invention relates to a method of forming a battery, comprising forming a battery stack comprising an intercalation anode, a metal halide cathode in a conductive material, a separator positioned between the intercalation anode and the conductive material of the metal halide cathode, and an electrolyte comprising at least one cyclic ester compound, wherein an oxidizing gas is introduced into the battery stack, and the electrolyte is in contact with the intercalation anode, the metal halide cathode, and the oxidizing gas.

[0009] In other embodiments and aspects, the carbonate-based compound comprises at least two ethyl groups.

[0010] In further embodiments and aspects, the carbonate-based compound is selected from the group consisting of ethylene carbonate (EC), vinylene carbonate (VC), propylene carbonate (PC), diethyl carbonate (DEC), dipropyl carbonate (DPC), dibutyl carbonate (DBC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), ethyl propyl carbonate (EPC), ethyl butyl carbonate (EBC), ethyl salicylate carbonate (ESC), fluoroethylene carbonate (FEC), allyl methyl carbonate (AMC), dodecyl ethyl carbonate (DDEC), diethyl decarbonate (DEDC), and combinations thereof.

[0011] In other embodiments and aspects, the metal cation [M] + is Li+ , Mg 2+ , Zn 2+ , Al 3+ , Na + and is selected from the group consisting of these and combinations thereof.

[0012] In further embodiments and aspects, the anion [X] - is nitrate ion (NO3 - ), hexafluorophosphate ion (PF6 - ), tetrafluoroborate ion (BF4 - ), bis(oxalato)borate ion (BOB - ), difluoro(oxalato)borate ion (DFOB - ), trifluoromethanesulfonate ion (TF - ), trifluoromethanesulfonyl imide ion (TFSI - ), fluorosulfonyl imide ion (FSI - ) and is selected from the group consisting of these and combinations thereof.

[0013] In other embodiments and aspects, at least one cyclic ester compound is an additive to a carbonate-based electrolyte.

[0014] In further embodiments and aspects, at least one cyclic ester compound has a weight % concentration between 5% and 20% in the electrolyte.

[0015] In other embodiments and aspects, at least one cyclic ester compound is selected from the group consisting of beta-propiolactone (BPL), beta-butyrolactone (BBL), alpha-methyl-gamma-butyrolactone (AMGBL), gamma-butyrolactone (GBL), gamma-valerolactone (GVL), delta-valerolactone (DVL), gamma-caprolactone (GCL), epsilon-caprolactone (ECL), gamma-octalactone (GOL), gamma-nonalactone (GNL), gamma-decalactone (GDL), delta-decalactone (DDL), gamma-undecalactone (GUL), delta-undecalactone (DUL), delta-dodecalactone (DDDL), and combinations thereof.

[0016] In further embodiments and aspects, at least one cyclic ester compound is gamma-butyrolactone (GBL) or epsilon-caprolactone (ECL) or both.

[0017] In other embodiments and aspects, the intercalation anode is selected from the group consisting of graphite, graphene, reduced graphene oxide (RGO), silicon, silicon alloy, silicon-carbon composite, carbon nanotube, fullerene, titanium dioxide (TiO2), titanium disulfide (TiS2), molybdenum dioxide (MoO2), molybdenum trioxide (MoO3), molybdenum disulfide (MoS2), and combinations thereof.

[0018] In further embodiments and aspects, the intercalation anode comprises graphite.

[0019] In other embodiments and aspects, the metal halide of the cathode is (i) metal ions selected from the group consisting of Li + , Mg + , Zn + , Al + , Na + and combinations thereof, (ii) I - , Br - , Cl - , F- It contains halide ions selected from the group consisting of and combinations thereof.

[0020] In further embodiments and aspects, the cathode is a conversion cathode selected from the group consisting of lithium iodide (LiI), lithium chloride (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), sodium chloride (NaCl), sodium iodide (NaI2), nickel chloride (NiCl2), zinc bromide (ZnBr2), zinc chloride (ZnCl2) and combinations thereof.

[0021] In other embodiments and aspects, the conductive material is selected from the group consisting of carbon black, carbon paper, carbon foam, carbon fiber, carbon nanofiber, carbon nanotube, activated carbon, amorphous carbon, graphite sheet, graphene, reduced graphene oxide and combinations thereof.

[0022] In further embodiments and aspects, the oxidizing gas is selected from the group consisting of oxygen, air, nitric oxide, nitrogen dioxide and combinations thereof.

[0023] Additional embodiments or aspects or both of the present invention are presented non - limitatively in the forms for carrying out the invention described below.

Brief Description of the Drawings

[0024]

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DETAILED DESCRIPTION OF THE INVENTION

[0025] A description of what is presently considered to be the preferred embodiment or embodiments, or both, of the claimed invention is set forth below. It is intended that any alternatives or modifications in function, purpose or structure be encompassed by the appended claims. As used in this specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. As used in this specification and the appended claims, the terms "comprise", "comprised", "comprises" or "comprising", or any combination thereof, specify the presence of the expressly recited components, elements, features or steps, or combinations thereof, but do not preclude the presence or addition of one or more other components, elements, features or steps, or combinations thereof.

[0026] As used herein, the term "metal halide" refers to a compound having a metal and a halogen. The metal of the metal halide can be any metal in Groups 1 to 16 of the periodic table, but is usually an alkali metal of Group 1. The halide of the metal halide is any halogen in Group 17 of the periodic table.

[0027] As used herein, the term "cathode" refers to the positive electrode of a battery cell that receives electrons from an external circuit and is reduced during discharge, and transfers electrons to the external circuit by oxidation during charging. In a metal halide battery, the cathode material comprises the metal halide as defined above. A suitable cathode material for a rechargeable metal halide battery may also be a conversion-type cathode material, which is an electrode material that undergoes a conversion reaction according to Equation (1) or Equation (2):

Number

Number

[0028] Unlike lithium-ion and nickel metal hydride (NiMH) batteries, metal halide batteries do not require heavy metal cathode materials (such as cobalt or nickel, respectively). Therefore, rechargeable metal halide batteries potentially have a lower manufacturing cost than conventional lithium-ion batteries or NiMH batteries. Furthermore, since rechargeable metal halide batteries do not require lithium metal, these batteries also have a reduced risk of ignition and thus operate more safely than rechargeable batteries that require lithium metal for operation and are used in the art.

[0029] As used herein, the term "anode" refers to the negative electrode of a battery cell that, during discharge, transfers electrons to an external circuit by oxidation and, during charging, receives electrons from the external circuit and is reduced. Suitable anode materials for rechargeable metal halide batteries may be intercalation-type anode materials, which have a reaction mechanism between the metal ions of the metal halide cathode material (including lithium for conversion-type cathode materials) and the anode material during the intercalation / deintercalation process, where the metal ions are inserted into stable sites within or on the surface of the anode material (during charging) and subsequently released therefrom (during discharge). Exemplary intercalation-type anode materials will typically have a lattice structure. Materials capable of forming such a lattice structure include carbon allotropes, silicon compounds, titanium compounds, and molybdenum compounds.

[0030] As used herein, the term "electrolyte" refers to a material that provides ion transport between the anode and cathode of a battery cell. The electrolyte serves as a conduction path for ion transport by interacting with the anode and cathode. During charging of the battery, the electrolyte facilitates the movement of ions from the cathode to the anode, while during discharge, the electrolyte facilitates the movement of ions from the anode to the cathode. In a rechargeable battery, the electrolyte promotes the formation of an ion cycle between the anode and cathode.

[0031] As used herein, the term "oxidizing gas" refers to a gas that induces a reduction-oxidation (redox) reaction in a battery cell. Examples of oxidizing gases include, but are not limited to, oxygen, air, nitric oxide, nitrogen dioxide, and combinations thereof. As is well known to those skilled in the art, a redox reaction is a reaction that transfers electrons between (i) a reducing agent that undergoes oxidation by loss of electrons and (ii) an oxidizing agent that undergoes reduction by gain of electrons. In the context of the present invention, the oxidizing gas cooperates with the electrolyte to form a stable SEI (solid-electrolyte interface phase) layer on the surface of the electrodes of a rechargeable metal halide battery and to promote the redox reaction of the active cathode material.

[0032] The rechargeable metal halide battery described in this specification comprises an anode, a metal halide cathode, an oxidizing gas, and an electrolyte in contact with the anode, the cathode, and the oxidizing gas. The battery has high output, rapid chargeability, and electrical stability. The combination of battery components enables the cycle life of the metal halide battery to be extended up to a maximum of 1000 cycles at a current density that allows the battery to be charged within 10 to 15 minutes (e.g., FIGS. 10 to 12, Examples 7 to 9).

[0033] In one embodiment, the metal halide cathode of the rechargeable metal halide battery comprises (i) metal ions selected from the group consisting of Li + , Mg 2+ , Zn 2+ , Al 3+ , Na + and combinations thereof, and (ii) halogen ions selected from the group consisting of I - , Br - , Cl - , F - and combinations thereof. When the metal halide cathode is a conversion cathode, the conversion cathode material can include, without limitation, lithium iodide (LiI), lithium chloride (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), sodium chloride (NaCl), sodium iodide (NaI2), nickel chloride (NiCl2), zinc bromide (ZnBr2), zinc chloride (ZnCl2), and combinations thereof.

[0034] In another embodiment, the anode of the rechargeable metal halide battery is an intercalation anode. Intercalation anode materials that can be used in rechargeable metal halide batteries include, without limitation, graphite, graphene, reduced graphene oxide (RGO), silicon, silicon alloys, silicon-carbon composites, carbon nanotubes, fullerenes, titanium dioxide (TiO2), titanium disulfide (TiS2), molybdenum dioxide (MoO2), molybdenum trioxide (MoO3), molybdenum disulfide (MoS2), and combinations thereof.

[0035] In a further embodiment, the metal halide cathode may be incorporated into a conductive material such as a carbon current collector or porous carbon or both. Examples of conductive materials that can be used to incorporate the cathode material include, without limitation, carbon black, carbon paper, carbon foam, carbon fiber, carbon nanofiber, carbon nanotube, activated carbon, amorphous carbon, graphite sheet, graphene, reduced graphene oxide, and combinations thereof. Depending on the conductive material used, the metal halide may be dispersed within the conductive material or adsorbed on the surface of the conductive material. When the conductive material is a porous material, the metal halide may be incorporated into a plurality of pores of the porous material.

[0036] In another embodiment, the electrolyte for a rechargeable metal halide battery comprises a compound based on a carbonate having at least one ethyl group. In a further embodiment, the electrolyte comprises a compound based on a carbonate having at least two ethyl groups. Examples of such compounds based on carbonates that can be used in the battery electrolyte include, but are not limited to, ethylene carbonate (EC), vinylene carbonate (VC), propylene carbonate (PC), diethyl carbonate (DEC), dipropyl carbonate (DPC), dibutyl carbonate (DBC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), ethyl propyl carbonate (EPC), ethyl butyl carbonate (EBC), ethyl salicylate carbonate (ESC), fluoroethylene carbonate (FEC), allyl methyl carbonate (AMC), dodecyl ethyl carbonate (DDEC), diethyl decarbonate (DEDC), and combinations thereof.

[0037] In another embodiment, the electrolyte comprises an ion-conductive salt having a metal cation [M] + [X] - and an anion [X] + . Examples of metal cations that can constitute the ion-conductive salt of the electrolyte solution include, but are not limited to, Li - , Mg + , Zn 2+ , Al 2+ , Na 3+ , and combinations thereof. Examples of anions that can constitute the ion-conductive salt include, but are not limited to, nitrate ion (NO3 + ), hexafluorophosphate ion (PF6 - ), tetrafluoroborate ion (BF4 - ), bisoxalatoborate ion (BOB - ), difluorooxalatoborate ion (DFOB - ), trifluoromethanesulfonate ion (TF - ), trifluoromethanesulfonyl imide ion (TFSI - ), and -) Fluorosulfonylimide ion (FSI - ) and combinations thereof.

[0038] In a further embodiment, the electrolyte comprises at least one cyclic ester or lactone (cyclic carboxylic acid ester) or both. The at least one cyclic ester or lactone or both are collectively referred to herein as "cyclic esters". The cyclic ester may be used as an additive to a carbonate-based electrolyte. Examples of such cyclic esters include, but are not limited to, beta-propiolactone (BPL), beta-butyrolactone (BBL), alpha-methyl-gamma-butyrolactone (AMGBL), gamma-butyrolactone (GBL), gamma-valerolactone (GVL), delta-valerolactone (DVL), gamma-caprolactone (GCL), epsilon-caprolactone (ECL), gamma-octalactone (GOL), gamma-nonalactone (GNL), gamma-decalactone (GDL), delta-decalactone (DDL), gamma-undecalactone (GUL), delta-undecalactone (DUL), delta-dodecalactone (DDDL) and combinations thereof.

[0039] A rechargeable metal halide battery manufactured with the components described herein may further include a separator between the anode and the cathode. In one embodiment, the battery stack is formed by placing a separator between an intercalation anode and a metal halide cathode. In a further embodiment, the battery stack is formed by placing a separator between an intercalation anode and a conductive material, the latter of which incorporates a metal halide cathode. In another embodiment, the separator described herein is immersed in an electrolyte solution and then incorporated into the battery stack. In a further embodiment, the electrolyte solution is introduced into the battery stack either during or after formation of the stack. In another embodiment, an oxidizing gas is introduced into the battery stack. During operation, the metal halide battery is charged after introduction of the oxidizing gas into the battery stack. To return the battery to a standby state, the oxidizing gas may be removed by purging the battery with an inert gas. Examples of inert gases include, but are not limited to, argon (Ar), nitrogen (N), helium (He), neon (Ne), xenon (Xe), krypton (Kr), and combinations thereof.

[0040] The following discussion presents data derived from a battery operated with a graphite anode, a lithium iodide (LiI) cathode, an electrolyte solution containing 1M lithium hexafluorophosphate (LiPF6) as an ion-conductive salt dissolved in various different carbonate ester solutions (with and without cyclic ester additives), and oxygen as the oxidizing gas. It should be understood that the graphite anode, LiI cathode, electrolyte solution, and oxygen are used as exemplary materials and are not intended to be limited to the various different battery combinations disclosed herein.

[0041] Figure 1 shows 1 mA / cm 2Graph showing the first charge / discharge cycle of a rechargeable metal halide battery driven at a current density of 2 and comprising graphite as the anode material, LiI as the active cathode material, an electrolyte solution of 1 M LiPF6 dissolved in an organic solution of EC-DEC (1:1 by volume), and oxygen as the catalyst (Example 1). Figure 7 shows the same battery as in Figure 1 but operating at a current density of 5 mA / cm

[0042] Figure 2 is a graph of the cycle performance showing the first charge / discharge cycle of a rechargeable metal halide battery operating at a current density of 1 mA / cm 2 without using oxygen as the catalyst, comprising graphite as the anode material, LiI as the active cathode material, and an electrolyte solution of 1 M LiPF6 dissolved in EC-DEC (1:1 by volume) (Comparative Example 1). The first cycle results in Figure 2 show that when normalized by the amount of lithium iodide, the current efficiency is less than 70%, the coulombic efficiency is less than 10%, and the specific capacity is less than 10 mAh / g. When oxygen is removed from the battery in Figure 1, the rechargeability and lifespan of the battery are significantly reduced.

[0043] Figure 3 shows a current density of 1 mA / cm 2A graph of cycle performance showing the first charge / discharge cycle of a rechargeable metal halide battery operating at a current density of

[0044] Figure 4 shows a 2 graph of cycle performance showing the first charge / discharge cycle of a rechargeable metal halide battery operating at a current density of 1 mA / cm², with graphite as the anode material, LiI as the active cathode material, an electrolyte solution of 1 M LiPF6 dissolved in EC-EMC (1:1 by volume), and oxygen as the catalyst (Example 3). The results of the first cycle in Figure 4, when normalized by the amount of lithium iodide, show that both the current efficiency and the Coulombic efficiency exceed 95%, and the specific capacity is higher than 125 mAh / g.

[0045] Figure 5 shows a 2 graph of cycle performance showing the first charge / discharge cycle of a rechargeable metal halide battery operating at a current density of 1 mA / cm², with graphite as the anode material, LiI as the active cathode material, and an electrolyte solution of 1 M LiPF6 dissolved in EC-DMC (1:1 by volume), without using oxygen as the catalyst (Comparative Example 2). The results of the first cycle in Figure 5, when normalized by the amount of lithium iodide, show that the current efficiency is less than 70%, the Coulombic efficiency is less than 60%, and the specific capacity is less than 100 mAh / g. Removing oxygen also results in a battery with reduced rechargeability and lifespan.

[0046] Figure 6 shows a 2Graph of cycle performance showing the first and fifth charge / discharge cycles of a rechargeable metal halide battery operating at a current density of

[0047] 5 mA / cm 2 , with graphite as the anode material, LiI as the active cathode material, 3-methoxypropionitrile (MPN) as the electrolyte solution, and oxygen as the catalyst (Comparative Example 3). MPN represents an electrolyte solution that does not contain a carbonate ester having at least one ethyl group. The results of the first cycle in Figure 6, when normalized by the amount of lithium iodide, show that both the current efficiency and the Coulombic efficiency are less than 80%, and the specific capacity is higher than 100 mAh / g. In the fifth cycle, the specific capacity decreases to less than 80 mAh / g, representing less than 80% of the original capacity of the battery. The results of Figure 6 demonstrate that the carbonate ester electrolyte operating under oxygen described herein has superior rechargeability and efficiency compared to nitrile ester electrolytes such as MPN.

[0047] Figure 8 is a graph of cycle performance showing the first charge / discharge cycle of a rechargeable metal halide battery operating at a current density of 5 mA / cm 2 , with graphite as the anode material, LiI as the active cathode material, an electrolyte solution of 1 M LiPF6 dissolved in EC-DEC (1:1 volume %), an electrolyte additive GBL (10 wt %), and oxygen as the catalyst (Example 5). The results of the first cycle in Figure 8, when normalized by the amount of lithium iodide, show that both the current efficiency and the Coulombic efficiency exceed 85%, and the specific capacity is higher than 100 mAh / g.

[0048] Figure 9 is a graph of cycle performance showing the first charge / discharge cycle of a rechargeable metal halide battery operating at a current density of 5 mA / cm 2Graph showing the first charge / discharge cycle of a rechargeable metal halide battery operating at a current density of [[0]], with graphite as the anode material, LiI as the active cathode material, an electrolyte solution of 1 M LiPF6 dissolved in EC-DEC (1:1 by volume), and an electrolyte additive ECL (10 wt%), and oxygen as the catalyst (Example 6). The results of the first cycle in Figure 9, when normalized by the amount of lithium iodide, show that both the current efficiency and the Coulombic efficiency exceed 80%, and the specific capacity is higher than 100 mAh / g.

[0049] Figure 10 is a graph of cycle life comparing different electrolyte solutions in a rechargeable metal halide battery cell with graphite as the anode material and LiI as the active cathode material, using a battery operated at a current density of 5 mA / cm 2 under oxygen. The electrolyte solutions being compared are: (1) 1 M LiPF6 in EC-DEC (1:1 by volume) (without additives), (2) 1 M LiPF6 in EC-DEC (1:1 by volume) containing the GBL additive (10 wt%), and (3) 1 M LiPF6 in EC-DEC (1:1 by volume) containing the ECL additive (10 wt%) (Example 7). As shown in Figure 10, the battery cells with GBL and ECL electrolyte additives demonstrate a longer cycle life (>500) compared to the battery without electrolyte additives. The battery with the GBL additive achieves nearly 1000 cycles at 80% of its initial capacity and maintains a discharge capacity exceeding 100 mAh / g at the 1000th cycle.

[0050] Figure 11 is a graph of cycle life comparing different weight percentages of the electrolyte additive GBL in a rechargeable metal halide battery cell with graphite as the anode material and LiI as the active cathode material, and the battery is operated at 5 mA / cm 2It is operated at a current density of

[0051] Figure 12 shows a graph of cycle life comparing different weight percentages of electrolyte additive ECL in a rechargeable metal halide battery cell with graphite as the anode material and LiI as the active cathode material, using a battery operated at a current density of 5 mA / cm 2 under oxygen. The electrolyte solution is 1 M LiPF6 dissolved in EC-DEC (1:1 volume %) containing ECL added to the electrolyte solution at the following weight percentages: 0%, 10%, 20%, 30%, 50% and 100% (Example 9). As shown in Figure 12, the electrolyte solution containing 10 wt% ECL has 689 charge / discharge cycles at 80% of its best cycle capacity and shows the longest cycle life of over 900 at 80% of its first cycle capacity (see Figure 10). Battery cells with more than 10 wt% ECL in the electrolyte solution show a decrease in cycle life. At 100 wt% ECL, the battery operates for less than 20 charge / discharge cycles.

[0052] The figures and examples presented herein show that a combination of an intercalation anode (such as graphite), a metal halide cathode, a carbonate ester-based electrolyte, at least one cyclic ester additive, and an oxidizing gas can improve the cycle life of a rechargeable battery by more than 900%, achieving nearly 100 cycles at 80% of the original capacity (e.g., Figures 10 - 12, Examples 7 - 9).

[0053] The description of various aspects or embodiments or both of the present invention is presented for illustrative purposes and is not intended to be exhaustive or to limit the invention to the disclosed embodiments. Numerous 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 is chosen to best explain the principles of an aspect or embodiment or both, the practical application, or the technical improvements over the technologies found in the marketplace, or to enable those skilled in the art to understand the aspects or embodiments or both disclosed herein.

Examples

[0054] The following examples are described to provide those skilled in the art with a complete disclosure of how to make and use aspects or embodiments or both of the invention described herein. Efforts have been made to ensure accuracy with respect to variables such as amounts, temperatures, etc., but experimental errors and deviations should be taken into account. Unless otherwise indicated, parts are parts by weight, temperature is in degrees Celsius, and pressure is at or near atmospheric pressure. All components are commercially available unless otherwise indicated.

[0055] For each of the examples, the same materials and cell manufacturing techniques were used. The following materials were purchased from Sigma Aldrich (St. Louis, MO, USA): 1M lithium hexafluorophosphate (LiPF6), ethylene carbonate (EC) - diethyl carbonate (DEC) (1:1 volume %) electrolyte solution, gamma - butyrolactone (GBL), epsilon - caprolactone (ECL), and lithium iodide (LiI). The above - mentioned materials were dried and stored in an argon - filled glove box (<0.1 ppm H2O, O2). The LiI cathode was prepared by incorporating LiI into a carbon cloth current collector at a mass loading of 3 oz / yd 2 (102 g / m 2 ). (ZOLTEK(R) PX30, Zoltek Corporation, St. Louis, MO, USA). GBL or ECL was used as an electrolyte additive and evaluated at different weight ratios in the presence of oxidizing gases. A CELGARD(R) (Celgard, LLC, Charlotte, NC, USA) separator was placed between the graphite anode and the LiI cathode. The separator was wetted with the electrolyte solution. All cell assemblies were carried out in an argon - filled glove box. All cell components were placed in a cell equipped with inlet and outlet SWAGELOK(R) (Swagelok Company, Solon, OH, USA) tubes for oxygen flow. After introducing oxygen from the inlet tube outside the argon - filled glove box, the cell was completely sealed by closing the valves on both the inlet and outlet tubes.

[0056] (Example 1) Performance of the rechargeable lithium iodide - graphite cell 1M LIPF6 EC - DEC electrolyte (1:1 volume %), under oxygen (1 mA / cm 2 ) A rechargeable lithium iodide battery with a graphite anode and an electrolyte solution of 1M LiPF6 and EC - DEC (1:1 volume %) as the active cathode material was under oxygen at 1 mA / cm 2It was operated at a current density of. Figure 1 shows the current efficiency, Coulomb efficiency, and specific capacity (normalized by the amount of lithium iodide) in the first charge / discharge cycle.

[0057] (Comparative Example 1) Performance of a rechargeable lithium iodide graphite cell 1M LIPF6 EC-DEC electrolyte (1:1 volume %), under argon (1 mA / cm 2 ) A rechargeable lithium iodide battery comprising a graphite anode, 1M LiPF6 as the active cathode material, and an electrolyte solution of 1M LiPF6 EC-DEC (1:1 volume %) was operated under argon at a current density of 1 mA / cm 2 Figure 2 shows the current efficiency, Coulomb efficiency, and specific capacity (normalized by the amount of lithium iodide) in the first charge / discharge cycle.

[0058] (Example 2) Performance of a rechargeable lithium iodide graphite cell 1M LIPF6 EC-DPC electrolyte (1:1 volume %), under oxygen (1 mA / cm 2 ) A rechargeable lithium iodide battery comprising a graphite anode, 1M LiPF6 as the active cathode material, and an electrolyte solution of 1M LiPF6 EC-DPC (1:1 volume %) was operated under oxygen at a current density of 1 mA / cm 2 Figure 3 shows the current efficiency, Coulomb efficiency, and specific capacity (normalized by the amount of lithium iodide) in the first charge / discharge cycle.

[0059] (Example 3) Performance of a rechargeable lithium iodide graphite cell 1M LIPF6 EC-EMC electrolyte (1:1 volume %), under oxygen (1 mA / cm 2 ) A rechargeable lithium iodide battery comprising a graphite anode and an electrolyte solution of 1M LiPF6 EC-EMC (1:1 volume %) was operated under oxygen at a current density of 1 mA / cm 2It was operated at a current density of. Figure 4 shows the current efficiency, Coulomb efficiency, and specific capacity (normalized by the amount of lithium iodide) in the first charge / discharge cycle.

[0060] (Comparative Example 2) Performance of a rechargeable lithium iodide / graphite cell 1M LIPF6 EC-DMC electrolyte (1:1 volume %), under argon (1 mA / cm 2 ) A rechargeable lithium iodide battery comprising a graphite anode and an electrolyte solution of 1M LiPF6 EC-DMC (1:1 volume %) was operated under argon at a current density of 1 mA / cm 2 . Figure 5 shows the current efficiency, Coulomb efficiency, and specific capacity (normalized by the amount of lithium iodide) in the first charge / discharge cycle.

[0061] (Comparative Example 3) Performance of a rechargeable lithium iodide / graphite cell MPN electrolyte, under oxygen A rechargeable lithium iodide battery comprising a graphite anode and an electrolyte solution of MPN was operated under oxygen at a current density of 1 mA / cm 2 . Figure 6 shows the current efficiency, Coulomb efficiency, and specific capacity (normalized by the amount of lithium iodide) in the first and fifth charge / discharge cycles.

[0062] (Example 4) Performance of a rechargeable lithium iodide / graphite cell 1M LIPF6 EC-DEC electrolyte (1:1 volume %), under oxygen (5 mA / cm 2 ) A rechargeable lithium iodide battery comprising a graphite anode and an electrolyte solution of 1M LiPF6 EC-DEC (1:1 volume %) was operated under oxygen at a current density of 5 mA / cm 2 . Figure 7 shows the current efficiency, Coulomb efficiency, and specific capacity (normalized by the amount of lithium iodide) in the first charge / discharge cycle.

[0063] (Example 5) Performance of a rechargeable lithium iodide graphite cell 1M LIPF6 EC-DEC electrolyte (1:1 volume %) containing GBL additive (10 wt %), under oxygen (5 mA / cm 2 ) A rechargeable lithium iodide battery comprising a graphite anode and an electrolyte solution of 1M LiPF6 EC-DEC (1:1 volume %) containing electrolyte additive GBL (10 wt %) was operated under oxygen at a current density of 5 mA / cm 2 . Figure 8 shows the current efficiency, Coulombic efficiency and specific capacity (normalized by the amount of lithium iodide) in the first charge / discharge cycle.

[0064] (Example 6) Performance of a rechargeable lithium iodide graphite cell 1M LIPF6 EC-DEC electrolyte (1:1 volume %) containing ECL additive (10 wt %), under oxygen (5 mA / cm 2 ) A rechargeable lithium iodide battery comprising a graphite anode and an electrolyte solution of 1M LiPF6 EC-DEC (1:1 volume %) containing electrolyte additive ECL (10 wt %) was operated under oxygen at a current density of 5 mA / cm 2 . Figure 9 shows the current efficiency, Coulombic efficiency and specific capacity (normalized by the amount of lithium iodide) in the first charge / discharge cycle.

[0065] (Example 7) Performance of a rechargeable lithium iodide graphite cell 1M LIPF6 EC-DEC electrolyte (1:1 volume %) with and without additives, under oxygen (5 mA / cm 2 ) Under oxygen, current density 5 mA / cm 2A rechargeable lithium iodide battery comprising a graphite anode and the following electrolyte solutions that were operated in [conditions] was compared: (1) 1M LiPF6 EC-DEC (1:1 volume %) (without additives), (2) 1M LiPF6 EC-DEC (1:1 volume %) containing a GBL additive (10 wt %), and (3) 1M LiPF6 EC-DEC (1:1 volume %) containing an ECL additive (10 wt %). Figure 10 shows the cycle life of a lithium iodide battery, a battery with a GBL additive, and a battery with an ECL additive as a function of specific capacity (mAh / g) for the case of a battery without additives.

[0066] (Example 8) Performance of a Rechargeable Lithium Iodide Graphite Cell A 1M LIPF6 EC-DEC electrolyte (1:1 volume %) containing GBL additives in various weight ratios, under oxygen (5 mA / cm 2 ) A rechargeable lithium iodide battery comprising a graphite anode, a 1M LiPF6 EC-DEC (1:1 volume %) electrolyte solution, and GBL additives in the following weight percentages with respect to the electrolyte was operated under oxygen at a current density of 5 mA / cm 2 : 0%, 10%, 20%, 30%, 50%, and 100%. Figure 11 shows the cycle life at 80% of the original capacity (from Example 7) per GBL weight percentage.

[0067] (Example 9) Performance of a Rechargeable Lithium Iodide Graphite Cell A 1M LIPF6 EC-DEC electrolyte (1:1 volume %) containing ECL additives in various weight ratios, under oxygen (5 mA / cm 2 ) A rechargeable lithium iodide battery comprising a graphite anode, a 1M LiPF6 EC-DEC (1:1 volume %) electrolyte solution, and ECL additives in the following weight percentages with respect to the electrolyte was operated under oxygen at a current density of 5 mA / cm 2 : 0%, 10%, 20%, 30%, 50%, and 100%. Figure 12 shows the cycle life at 80% of the original capacity (from Example 7) per ECL weight percentage.

Claims

1. A graphite anode A cathode of LiI incorporated into a conductive material Oxygen, and An electrolyte of 1 M LiPF6 dissolved in ethylene carbonate diethyl carbonate (1:1 volume %) containing 10 wt % gamma-butyrolactone, in contact with the anode, the cathode and the oxygen A battery comprising the same.

2. A graphite anode A cathode of LiI incorporated into a conductive material Oxygen, and An electrolyte of 1 M LiPF6 dissolved in ethylene carbonate diethyl carbonate (1:1 volume %) containing 10 wt % epsilon-caprolactone, in contact with the anode, the cathode and the oxygen A battery comprising the same.

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