Battery pack comprising gel polymer electrolyte and method of making same

Abstract

The invention relates to a battery comprising a gel polymer electrolyte and a method of making the same. A battery circulating lithium ions includes a negative electrode, a positive electrode spaced apart from the negative electrode, and a gel polymer electrolyte disposed between the negative electrode and the positive electrode and configured to provide a lithium ion conducting medium between the negative electrode and the positive electrode. The positive electrode includes a high voltage electroactive material that is formulated to undergo lithium intercalation and deintercalation. The gel polymer electrolyte includes an aliphatic polyester, a lithium salt, and an ionic liquid. The aliphatic polyester includes substituted or unsubstituted poly (ethylene carbonate) (PEC). The lithium salt includes lithium sulfonimide, lithium borate, or a combination thereof. The ionic liquid comprises substantially equimolar amounts of cations and anions, the cations comprising a complex of lithium (Li +) and ethylene glycol dimethyl ether, imidazole ions, or a combination thereof, and the anions comprising sulfinate ions, borate ions, or a combination thereof.

Description

Technical Field

[0001] The present disclosure relates to electrolytes for cycling lithium ion batteries, and more particularly to gel polymer electrolytes comprising a polymer, a lithium salt, and an ionic liquid. Background Art

[0002] The information provided in this section is intended to generally introduce the background of the present disclosure. To the extent that work currently named as inventors is described in this section, and aspects of the specification that may not have been otherwise identified as prior art at the time of filing, are not admitted, either explicitly or implicitly, as prior art to the present disclosure.

[0003] A battery pack for circulating lithium ions generally includes a positive electrode, a negative electrode spaced apart from the positive electrode, and an ion-conductive electrolyte that provides a lithium ion conducting medium between the positive and negative electrodes during discharge and charge of the battery pack. In order to provide a battery pack having high energy density, high power density and high voltage of such a battery pack, the materials for the negative electrode and the positive electrode should be selected to maximize the electrochemical potential difference between the negative electrode and the positive electrode. In order to help maintain the cycling stability of the battery pack, the electrolyte should be formulated to have a wide electrochemical stability window to avoid undesirable chemical reactions between the electrolyte and the negative and / or positive electrodes during cycling. Summary of the invention

[0004] According to one or more embodiments of the present disclosure, a battery pack for circulating lithium ions includes a negative electrode, a positive electrode spaced apart from the negative electrode, and a gel polymer electrolyte disposed between the negative electrode and the positive electrode and configured to provide a lithium ion conductive medium between the negative electrode and the positive electrode. The positive electrode includes a high voltage electroactive material configured to undergo lithium insertion and extraction. The gel polymer electrolyte includes an aliphatic polyester, a lithium salt, and an ionic liquid. The aliphatic polyester includes a substituted or unsubstituted poly (ethylene carbonate) (PEC). The lithium salt includes lithium sulfonimide, lithium borate, or a combination thereof. The ionic liquid includes substantially equimolar amounts of cations and anions. The cations include lithium (Li + ) and ethylene glycol dimethyl ether, imidazolium ion, or a combination thereof. The anion includes a sulfinate ion, a borate ion, or a combination thereof.

[0005] The substituted or unsubstituted PEC may include a PEC homopolymer composed of repeating substituted or unsubstituted ethylene carbonate monomer units, a PEC-based copolymer mainly including repeating substituted or unsubstituted ethylene carbonate monomer units, or a combination thereof.

[0006] The aliphatic polyester may further comprise an aliphatic polycarbonate, an aliphatic polylactone or a combination thereof, wherein the aliphatic polycarbonate comprises a 1 - the main repeating monomer unit, wherein R 1 is a substituted or unsubstituted divalent hydrocarbon group, the aliphatic polylactone comprises a 2 - the main repeating monomer unit, wherein R 2 is a substituted or unsubstituted divalent hydrocarbon group.

[0007] The aliphatic polyester may further include substituted or unsubstituted poly(propylene carbonate) (PPC), poly(trimethylene carbonate) (PTMC), polycaprolactone (PCL), poly(propiolactone) (PPL), or a combination thereof.

[0008] The aliphatic polyester may account for greater than or equal to about 5% and less than or equal to about 30% by weight of the gel polymer electrolyte.

[0009] The lithium salt may include lithium bis(trifluoromethane)sulfonyl imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), or a combination thereof.

[0010] The lithium salt may account for greater than or equal to about 40% and less than or equal to about 90% by weight of the gel polymer electrolyte.

[0011] The cation of the ionic liquid may include lithium (Li + ) and triethylene glycol dimethyl ether complex, lithium (Li + ) and tetraethylene glycol dimethyl ether complex or a combination thereof. The anion of the ionic liquid may include bis(fluorosulfonyl)imide (FSI), bis(trifluoromethane)sulfonylimide (TFSI), bis(oxalato)borate (BOB), difluorooxalatoborate (DFOB), or a combination thereof.

[0012] The ionic liquid may account for greater than or equal to about 5% and less than or equal to about 50% by weight of the gel polymer electrolyte.

[0013] The lithium salt may include lithium bis(trifluoromethane)sulfonyl imide (LiTFSI), and the cation of the ionic liquid may include lithium (Li + ) and triethylene glycol dimethyl ether, and the anion of the ionic liquid includes bis(trifluoromethane)sulfonyl imide (TFSI).

[0014] The gel polymer electrolyte may have a potential greater than or equal to about 5.5 volts vs. Li / Li + oxidation potential.

[0015] The gel polymer electrolyte may have an ionic conductivity of greater than or equal to about 8.5 mS / cm at 60 degrees Celsius (° C.).

[0016] The gel polymer electrolyte may further include a carrier including a microporous nonwoven material impregnated with and encapsulated in the gel polymer electrolyte.

[0017] According to one or more embodiments of the present disclosure, a circulating lithium ion battery pack includes a negative electrode, a positive electrode spaced apart from the negative electrode, and a gel polymer electrolyte disposed between the negative electrode and the positive electrode and configured to provide a lithium ion conductive medium between the negative electrode and the positive electrode. The negative electrode contains lithium greater than or equal to about 97% by weight. The positive electrode contains a high voltage electroactive material formulated to undergo lithium insertion and extraction. The gel polymer electrolyte contains an aliphatic polyester, a lithium salt, and an ionic liquid. The aliphatic polyester includes a substituted or unsubstituted poly(ethylene carbonate) (PEC). The lithium salt includes lithium bis(trifluoromethane)sulfonyl imide (LiTFSI). The ionic liquid contains substantially equimolar amounts of cations and anions, the cations including lithium (Li + ) and triethylene glycol dimethyl ether, and the anion includes bis(trifluoromethane)sulfonyl imide (TFSI). The lithium salt accounts for greater than or equal to about 40% and less than or equal to about 90% by weight of the gel polymer electrolyte.

[0018] The substituted or unsubstituted PEC may include a PEC homopolymer composed of repeating substituted or unsubstituted ethylene carbonate monomer units, a PEC-based copolymer mainly including repeating substituted or unsubstituted ethylene carbonate monomer units, or a combination thereof.

[0019] The aliphatic polyester may further comprise an aliphatic polycarbonate, an aliphatic polylactone or a combination thereof, wherein the aliphatic polycarbonate comprises a 1 - the main repeating monomer unit, wherein R 1 is a substituted or unsubstituted divalent hydrocarbon group, the aliphatic polylactone comprises a 2 - the main repeating monomer unit, wherein R 2 is a substituted or unsubstituted divalent hydrocarbon group.

[0020] The aliphatic polyester may account for greater than or equal to about 5% and less than or equal to about 30% by weight of the gel polymer electrolyte.

[0021] The cation of the ionic liquid may include lithium (Li +) and triethylene glycol dimethyl ether complex, lithium (Li + ) and tetraethylene glycol dimethyl ether, or a combination thereof. The anion of the ionic liquid may include bis(fluorosulfonyl)imide (FSI), bis(trifluoromethane)sulfonylimide (TFSI), bis(oxalato)borate (BOB), difluorooxalatoborate (DFOB), or a combination thereof.

[0022] The ionic liquid may account for greater than or equal to about 5% and less than or equal to about 50% by weight of the gel polymer electrolyte.

[0023] In a method for manufacturing a battery pack for circulating lithium ions, an electrolyte precursor is prepared. The electrolyte precursor comprises a solvated ionic liquid and an aliphatic polyester and a lithium salt dissolved in a polar aprotic organic solvent. The solvated ionic liquid comprises lithium bis(trifluoromethane)sulfonyl imide (TFSI)-triethylene glycol dimethyl ether, lithium bis(trifluoromethane)sulfonyl imide (TFSI)-tetraethylene glycol dimethyl ether, 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][TFSI]), or a combination thereof. The aliphatic polyester comprises substituted or unsubstituted poly(ethylene carbonate) (PEC). The lithium salt comprises lithium bis(trifluoromethane)sulfonyl imide (LiTFSI). The electrolyte precursor is applied to a substrate comprising a release film, a positive electrode or a microporous support structure. Then, the polar aprotic organic solvent is removed from the electrolyte precursor to form a gel polymer electrolyte on the substrate.

[0024] The present invention discloses the following scheme:

[0025] Solution 1. A circulating lithium ion battery pack, the battery pack comprising:

[0026] Negative electrode;

[0027] a positive electrode spaced apart from the negative electrode and comprising a high voltage electroactive material configured to undergo lithium intercalation and deintercalation; and

[0028] A gel polymer electrolyte disposed between the negative electrode and the positive electrode and configured to provide a lithium ion conductive medium between the negative electrode and the positive electrode, the gel polymer electrolyte comprising:

[0029] Aliphatic polyesters comprising substituted or unsubstituted poly(ethylene carbonate) (PEC),

[0030] A lithium salt comprising lithium sulfonimide, lithium borate, or a combination thereof, and

[0031] An ionic liquid comprising substantially equimolar amounts of cations and anions, wherein the cations include lithium (Li +) and ethylene glycol dimethyl ether, an imidazolium ion, or a combination thereof, and the anion includes a sulfinate ion, a borate ion, or a combination thereof.

[0032] Option 2. A battery pack according to Option 1, wherein the substituted or unsubstituted PEC comprises a PEC homopolymer composed of repeating substituted or unsubstituted ethylene carbonate monomer units, a PEC-based copolymer mainly comprising repeating substituted or unsubstituted ethylene carbonate monomer units, or a combination thereof.

[0033] Solution 3. The battery pack according to Solution 1, wherein the aliphatic polyester further comprises an aliphatic polycarbonate, an aliphatic polylactone, or a combination thereof, wherein the aliphatic polycarbonate comprises a 1 - the main repeating monomer unit, wherein R 1 is a substituted or unsubstituted divalent hydrocarbon group, the aliphatic polylactone comprises a 2 - the main repeating monomer unit, wherein R 2 is a substituted or unsubstituted divalent hydrocarbon group.

[0034] Option 4. A battery according to Option 1, wherein the aliphatic polyester further comprises substituted or unsubstituted poly(propylene carbonate) (PPC), poly(trimethylene carbonate) (PTMC), polycaprolactone (PCL), poly(propiolactone) (PPL), or a combination thereof.

[0035] Embodiment 5. The battery pack according to embodiment 1, wherein the aliphatic polyester accounts for greater than or equal to about 5% and less than or equal to about 30% by weight of the gel polymer electrolyte.

[0036] Option 6. A battery pack according to Option 1, wherein the lithium salt comprises lithium bis(trifluoromethane)sulfonyl imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), or a combination thereof.

[0037] Embodiment 7. The battery pack according to embodiment 1, wherein the lithium salt accounts for greater than or equal to about 40% and less than or equal to about 90% by weight of the gel polymer electrolyte.

[0038] Option 8. A battery pack according to Option 1, wherein the cation of the ionic liquid comprises lithium (Li + ) and triethylene glycol dimethyl ether complex, lithium (Li +) and tetraethylene glycol dimethyl ether, or a combination thereof, and wherein the anion of the ionic liquid comprises bis(fluorosulfonyl)imide (FSI), bis(trifluoromethane)sulfonylimide (TFSI), bis(oxalato)borate (BOB), difluorooxalatoborate (DFOB), or a combination thereof.

[0039] Embodiment 9. The battery pack according to embodiment 1, wherein the ionic liquid accounts for greater than or equal to about 5% and less than or equal to about 50% by weight of the gel polymer electrolyte.

[0040] Option 10. A battery according to Option 1, wherein the lithium salt comprises lithium bis(trifluoromethane)sulfonyl imide (LiTFSI), and the cation of the ionic liquid comprises lithium (Li + ) and triethylene glycol dimethyl ether, and the anion of the ionic liquid includes bis(trifluoromethane)sulfonyl imide (TFSI).

[0041] Embodiment 11. The battery pack according to embodiment 1, wherein the gel polymer electrolyte has a resistance greater than or equal to about 5.5 volts vs. Li / Li + oxidation potential.

[0042] Embodiment 12. The battery pack according to embodiment 1, wherein the gel polymer electrolyte has an ionic conductivity greater than or equal to about 8.5 mS / cm at 60 degrees Celsius (° C.).

[0043] Embodiment 13. The battery pack according to embodiment 1, wherein the gel polymer electrolyte further comprises:

[0044] A carrier comprising a microporous nonwoven material impregnated with and encapsulated in the gel polymer electrolyte.

[0045] Solution 14. A circulating lithium ion battery pack, the battery pack comprising:

[0046] a negative electrode comprising greater than or equal to about 97% lithium by weight;

[0047] a positive electrode spaced apart from the negative electrode and comprising a high voltage electroactive material configured to undergo lithium intercalation and deintercalation; and

[0048] A gel polymer electrolyte disposed between the negative electrode and the positive electrode and configured to provide a lithium ion conductive medium between the negative electrode and the positive electrode, the gel polymer electrolyte comprising:

[0049] Aliphatic polyesters comprising substituted or unsubstituted poly(ethylene carbonate) (PEC),

[0050] a lithium salt comprising lithium bis(trifluoromethane)sulfonyl imide (LiTFSI), and

[0051] An ionic liquid comprising substantially equimolar amounts of cations and anions, wherein the cations include lithium (Li + ) and triethylene glycol dimethyl ether, and the anion includes bis(trifluoromethane)sulfonyl imide (TFSI),

[0052] The lithium salt accounts for greater than or equal to about 40% and less than or equal to about 90% by weight of the gel polymer electrolyte.

[0053] Option 15. A battery pack according to Option 14, wherein the substituted or unsubstituted PEC comprises a PEC homopolymer composed of repeating substituted or unsubstituted ethylene carbonate monomer units, a PEC-based copolymer mainly comprising repeating substituted or unsubstituted ethylene carbonate monomer units, or a combination thereof.

[0054] Embodiment 16. The battery pack according to embodiment 14, wherein the aliphatic polyester further comprises an aliphatic polycarbonate, an aliphatic polylactone, or a combination thereof, wherein the aliphatic polycarbonate comprises a 1 - the main repeating monomer unit, wherein R 1 is a substituted or unsubstituted divalent hydrocarbon group, the aliphatic polylactone comprises a 2 - the main repeating monomer unit, wherein R 2 is a substituted or unsubstituted divalent hydrocarbon group.

[0055] Embodiment 17. The battery pack according to embodiment 14, wherein the aliphatic polyester accounts for greater than or equal to about 5% and less than or equal to about 30% by weight of the gel polymer electrolyte.

[0056] Option 18. A battery pack according to Option 14, wherein the cation of the ionic liquid comprises lithium (Li + ) and triethylene glycol dimethyl ether complex, lithium (Li + ) and tetraethylene glycol dimethyl ether, or a combination thereof, and wherein the anion of the ionic liquid comprises bis(fluorosulfonyl)imide (FSI), bis(trifluoromethane)sulfonylimide (TFSI), bis(oxalato)borate (BOB), difluorooxalatoborate (DFOB), or a combination thereof.

[0057] Embodiment 19. The battery pack according to embodiment 14, wherein the ionic liquid accounts for greater than or equal to about 5% and less than or equal to about 50% by weight of the gel polymer electrolyte.

[0058] Solution 20. A method for manufacturing a cycling lithium-ion battery, the method comprising:

[0059] preparing an electrolyte precursor, the electrolyte precursor comprising a solvated ionic liquid and an aliphatic polyester and a lithium salt dissolved in a polar aprotic organic solvent, the solvated ionic liquid comprising lithium bis(trifluoromethane)sulfonyl imide (TFSI)-triethylene glycol dimethyl ether, lithium bis(trifluoromethane)sulfonyl imide (TFSI)-tetraethylene glycol dimethyl ether, 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][TFSI]), or a combination thereof, the aliphatic polyester comprising a substituted or unsubstituted poly(ethylene carbonate) (PEC), and the lithium salt comprising lithium bis(trifluoromethane)sulfonyl imide (LiTFSI);

[0060] applying the electrolyte precursor to a substrate, the substrate comprising a release film, a cathode electrode, or a microporous support structure; and

[0061] The polar aprotic organic solvent is removed from the electrolyte precursor to form a gel polymer electrolyte on the substrate.

[0062] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings.The detailed description and specific examples are intended for illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The present disclosure will be more fully understood from the detailed description and accompanying drawings, in which:

[0064] Figure 1 is a schematic perspective view of a motor vehicle powered by a battery pack including a plurality of battery modules.

[0065] Figure 2 yes Figure 1 Schematic cross-sectional view of a portion of one of the battery modules of FIG. 1 , the battery module including a plurality of cycling lithium-ion electrochemical cells or batteries.

[0066] Figure 3 is a schematic cross-sectional view of a circulating lithium ion battery including a negative electrode, a positive electrode, and a gel polymer electrolyte sandwiched between the negative and positive electrodes.

[0067] Among the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0068] The gel polymer electrolytes of the present disclosure have a wide electrochemical stability window and can help improve the cycling stability of batteries that cycle lithium ions, particularly batteries that include high voltage positive electrode materials having an operating voltage greater than about 4.3 volts.

[0069] Figure 1 A motor vehicle 2 is depicted that is powered by an electric motor 4 that draws power from a battery pack 6 that includes one or more battery modules 8. The battery modules 8 may be electrically coupled together in a series and / or parallel arrangement to meet the desired capacity and power requirements of the electric motor 4. The vehicle 2 may be a pure electric vehicle and may be powered entirely by the electric motor 4, or the vehicle 2 may be a hybrid vehicle and may be powered by the electric motor 4 and an internal combustion engine (not shown).

[0070] like Figure 2 As shown in , each battery module 8 includes one or more electrochemical cells or batteries 10 that circulate lithium ions. In practice, the battery packs 10 in the battery module 8 are typically assembled as stacked layers, which include a negative electrode layer 12, a negative electrode current collector 13, a positive electrode layer 14, a positive electrode current collector 15, and a separator layer 16. Each battery pack 10 is defined by a negative electrode layer 12 and a positive electrode layer 14 separated from each other by a separator layer 16. In practice, the separator layer 16 can be permeated with an electrolyte that is used to provide a lithium ion conductive medium between the negative electrode layer 12 and the positive electrode layer 14, or the separator layer 16 itself can be used as an electrolyte. The negative electrode layer 12 is disposed on the negative electrode current collector 13 and is electrically connected to the negative electrode current collector 13, and the positive electrode layer 14 is disposed on the positive electrode current collector 15 and is electrically connected to the positive electrode current collector 15. As shown Figure 2 As shown in , for efficiency, these layers can be stacked so that some of the negative electrode collectors 13 and some of the positive electrode collectors 15 are double-sided and include a negative electrode layer 12 or a positive electrode layer 14 on both sides thereof. In this arrangement, adjacent negative electrode layers 12 and positive electrode layers 14 share a single negative electrode collector 13 or positive electrode collector 15.

[0071] Figure 3 An electrochemical cell or battery 20 of circulating lithium ions is depicted. The battery 20 can generate an electrical current during discharge that can be used to power a load device (e.g., an electric motor 4), and can be recharged by connection to a power source. Figure 1 and 21 , in aspect, the battery pack 20 may be used to supply power to the motor 4 of the motor vehicle 2. Additionally or alternatively, the battery pack 20 may be used in other transportation applications (e.g., motorcycles, boats, tractors, buses, motorbikes, mobile homes, campers, tanks, and aircraft), and may be used to power stationary and / or portable electronic devices, components, and devices used in a wide variety of other industries and applications, including industrial, residential and commercial buildings, consumer products, industrial equipment and machinery, agricultural or farm equipment, and heavy machinery (as non-limiting examples).

[0072] The battery 20 includes a negative electrode 22, a positive electrode 24 spaced from the negative electrode 22, and a gel polymer electrolyte 26 sandwiched between opposing facing surfaces 38, 40 of the negative electrode 22 and the positive electrode 24. The negative electrode 22 is disposed on a negative electrode current collector 30, and the positive electrode 24 is disposed on a positive electrode current collector 32. In practice, the negative electrode current collector 30 and the positive electrode current collector 32 are electrically coupled to a power source or load 34 (e.g., a motor 4) via an external circuit 36. The negative electrode and the positive electrode 22, 24 are configured to establish an electrochemical potential difference between the negative electrode and the positive electrode 22, 24 when the battery 20 is at least partially charged. During discharge of the battery 20, the electrochemical potential established between the negative electrode and the positive electrode 22, 24 drives spontaneous reduction and oxidation (redox) reactions within the battery 20 and releases lithium ions and electrons at the negative electrode 22. The released lithium ions travel from the negative electrode 22 through the gel polymer electrolyte 26 to the positive electrode 24, while the electrons travel from the negative electrode 22 to the positive electrode 24 via the external circuit 36, which generates an electric current. After the negative electrode 22 has been partially or completely depleted of lithium, the battery 20 can be charged by connecting the negative and positive electrodes 22, 24 to the power source 34, which drives the non-spontaneous redox reaction within the battery 20 and releases lithium ions and electrons from the positive electrode 24. The repeated discharge and charge of the battery 20 may be referred to herein as a "cycle", with one complete charge event followed by a complete discharge event being considered a complete cycle.

[0073] The negative electrode 22 is configured to store and release lithium ions to facilitate charging and discharging, respectively, of the battery 20. The negative electrode 22 may be in the form of a continuous material layer disposed on a major surface of a negative electrode current collector 30.

[0074] In an embodiment, the negative electrode 22 may include an electrochemically active (electroactive) material (electroactive negative electrode material) that can store and release lithium ions by undergoing a reversible redox reaction with lithium during charging and discharging of the battery 20. Examples of electroactive negative electrode materials include lithium, lithium-based materials, lithium alloys (e.g., alloys of lithium and silicon, aluminum, indium, tin, or combinations thereof), carbon-based materials (e.g., graphite, activated carbon, carbon black, hard carbon, soft carbon, and / or graphene), silicon, silicon-based materials (e.g., silicon oxide, alloys of silicon and tin, iron, aluminum, cobalt, or combinations thereof and / or composites of silicon and / or silicon oxide and carbon), tin oxide, aluminum, indium, zinc, germanium, silicon oxide, lithium silicon oxide, lithium silicide, titanium oxide, lithium titanate, and combinations thereof. The electroactive material of negative electrode 22 may comprise greater than or equal to about 50%, optionally greater than or equal to about 60%, or optionally greater than or equal to about 70% and less than or equal to about 95%, optionally less than or equal to about 90%, or optionally less than or equal to about 80% by weight of negative electrode 22.

[0075] In an embodiment, wherein the negative electrode 22 comprises an electroactive negative electrode material other than lithium, the negative electrode 22 may be in the form of a granular material, and the particles of the electroactive material of the negative electrode 22 may be mixed with a polymer binder and an optional conductive material. The polymer binder may provide structural integrity for the negative electrode 22. Examples of polymer binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene propylene diene monomer (EPDM) rubber, styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), nitrile rubber (NBR), styrene-butadiene rubber (SBR), styrene-ethylene-butylene-styrene copolymer (SEBS), polyacrylates, alginates, polyacrylic acid, and combinations thereof. The conductive material may provide good conductivity for the negative electrode 22. Examples of conductive materials include carbon-based materials, metals (e.g., nickel), and / or conductive polymers. Examples of conductive carbon-based materials include carbon black (CB) (e.g., acetylene black), graphite, graphene (e.g., graphene nanosheets, GNPs), graphene oxide, carbon nanotubes (CNTs), and / or carbon fibers (e.g., carbon nanofibers). Examples of conductive polymers include polyaniline, polythiophene, polyacetylene, and / or polypyrrole. In an aspect, the negative electrode 22 can include a conductive material including carbon black.

[0076] In an embodiment, the negative electrode 22 may consist essentially of lithium or consist of lithium, and the negative electrode 22 may be in the form of a non-porous metal film or foil, such as a lithium metal film or a lithium metal foil. In this case, the negative electrode 22 may contain more than 97% lithium by weight, or optionally more than 99% lithium, and may be substantially free of elements or compounds that undergo a reversible redox reaction with lithium during operation of the battery 20. In addition, in this case, the negative electrode 22 may be substantially free of a polymer binder and / or a conductive material.

[0077] The positive electrode 24 is configured to store and release lithium ions during discharge and charge of the battery 20. The positive electrode 24 can be in the form of a continuous porous layer disposed on the main surface of the positive electrode current collector 32. The positive electrode 24 includes an electrochemically active (electroactive) material (electroactive positive electrode material), a polymer binder, and an optional conductive material. In one aspect, the electroactive material of the positive electrode 24 can be a granular material, and the particles of the electroactive material of the positive electrode 24 can be mixed with a polymer binder and an optional conductive material.

[0078] The electroactive material of the positive electrode 24 can store and release lithium ions by undergoing a reversible redox reaction with lithium at a higher electrochemical potential than the electrochemically active material of the negative electrode 22, so that there is an electrochemical potential difference between the negative electrode 22 and the positive electrode 24. The electroactive material of the positive electrode 24 can include a material capable of lithium insertion and deinsertion or a material capable of conversion reaction with lithium. In aspects, where the electroactive material of the positive electrode 24 includes an intercalation host material in which reversible insertion or insertion of lithium ions can occur, the electroactive material of the positive electrode 24 can include a lithium transition metal oxide. For example, the electroactive material of the positive electrode 24 may include a layered lithium transition metal oxide represented by the formula LiMeO2, an olivine-type lithium transition metal oxide represented by the formula LiMePO4, a monoclinic lithium transition metal oxide represented by the formula Li3Me2(PO4)3, a spinel-type lithium transition metal oxide represented by the formula LiMe2O4, hydroxyphosphite represented by one or both of the following formulas LiMeSO4F or LiMePO4F, or a combination thereof, wherein Me is a transition metal (e.g., Co, Ni, Mn, Fe, Al, V, or a combination thereof). In aspects where the electroactive material of positive electrode 24 comprises a conversion material, the electroactive material of positive electrode 24 may comprise sulfur, selenium, tellurium, iodine, a halide (e.g., a fluoride or chloride), a sulfide, a selenide, a telluride, an iodide, a phosphide, a nitride, an oxide, an oxysulfide, an oxyfluoride, a sulfur fluoride, a sulfur-oxyfluoride, or lithium and / or a metal compound thereof (e.g., a compound of iron, manganese, nickel, copper, and / or cobalt). The electroactive material of positive electrode 24 may comprise greater than or equal to about 50%, optionally greater than or equal to about 60%, or optionally greater than or equal to about 70% and less than or equal to about 95%, optionally less than or equal to about 90%, or optionally less than or equal to about 80% by weight of positive electrode 24.

[0079] In one aspect, the electroactive material of the positive electrode 24 may include a material having a voltage greater than about 4.3 volts (V), optionally greater than about 4.5 V, or optionally greater than about 4.7 V vs. Li / Li + In one aspect, the high voltage electroactive material of the positive electrode 24 may have a working voltage of greater than or equal to about 5V vs. Li / Li + Examples of high voltage electroactive positive electrode materials include nickel-rich layered oxides (LiNi 1-x M x O2, wherein M = Co, Mn and / or Al), lithium-rich layered oxides (Li 1+x M 1-x O2, where M = Mn, Ni and / or Co), spinel oxides (LiMn 2-xMO4, wherein M = Ni, Co and / or Mn), and polyanionic compounds. Examples of high voltage nickel-rich layered oxides include LiNiO2, LiNi 1-x M x O2 and Li[Ni 1-x- y Co x Mn y ]O2. Examples of lithium-rich layered oxides include (xLi2MnO3·(1-x)LiMO2, where M=Ni, Co and / or Mn). Examples of high voltage spinel oxides include LiNi 0.5 Mn 1.5 O4. Examples of high voltage polyanionic compounds include phosphates, silicates, sulfates, and combinations thereof.

[0080] The polymer binder is electrochemically inactive and may be included in the positive electrode 24 to provide structural integrity to the positive electrode 24 and / or to help the positive electrode 24 adhere to the main surface of the positive electrode current collector 32. Examples of polymer binders include polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), ethylene propylene diene monomer (EPDM) rubber, styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), nitrile rubber (NBR), styrene-butadiene rubber (SBR), styrene-ethylene-butylene-styrene copolymer (SEBS), polyacrylates, alginates, polyacrylic acid, and combinations thereof. The polymer binder may account for greater than or equal to about 1%, or optionally greater than or equal to about 5% and less than or equal to about 10% by weight of the positive electrode 24.

[0081] The optional conductive material is electrochemically inactive and may be included in the positive electrode 24 to provide sufficient conductivity to the positive electrode 24 to support electron penetration therein. Examples of conductive materials include carbon-based materials, metals (e.g., nickel), and / or conductive polymers. Examples of conductive carbon-based materials include carbon black (CB) (e.g., acetylene black), graphite, graphene (e.g., graphene nanosheets, GNPs), graphene oxide, carbon nanotubes (CNTs), and / or carbon fibers (e.g., carbon nanofibers). Examples of conductive polymers include polyaniline, polythiophene, polyacetylene, and / or polypyrrole. When included in the positive electrode 24, the optional conductive material may account for greater than 0%, optionally greater than or equal to about 1%, or optionally greater than or equal to about 5% and less than or equal to about 10% by weight of the positive electrode 24.

[0082] The gel polymer electrolyte 26 is disposed between the negative electrode 22 and the positive electrode 24 and is configured to provide a lithium ion conductive medium between the negative electrode 22 and the positive electrode 24. The gel polymer electrolyte 26 physically separates and electrically isolates the negative electrode 22 and the positive electrode 24 from each other while allowing lithium ions to pass through. The gel polymer electrolyte 26 can be sandwiched between the negative electrode 22 and the positive electrode 24, and can be in direct physical contact with the opposite facing surfaces 38, 40 of the negative electrode 22 and the positive electrode 24. The gel polymer electrolyte 26 can have a thickness of greater than or equal to about 5 micrometers (μm), optionally greater than or equal to about 10 μm, or optionally greater than or equal to about 20 μm and less than or equal to about 500 μm, optionally less than or equal to about 200 μm, or optionally less than or equal to about 50 μm.

[0083] The gel polymer electrolyte 26 comprises an aliphatic polyester, a lithium salt, an ionic liquid, and an optional support structure.

[0084] The aliphatic polyester is formulated to provide the gel polymer electrolyte 26 with flexibility and the ability to establish a strong interfacial contact with the facing surface 38 of the negative electrode 22 and the facing surface 40 of the positive electrode 24. In addition, the aliphatic polyester is formulated to provide the gel polymer electrolyte 26 with a relatively wide electrochemical stability window. For example, compared to poly(ethylene oxide), the aliphatic polyester can provide the gel polymer electrolyte 26 with a relatively high oxidation potential, so that the gel polymer electrolyte 26 can be positioned in direct physical contact with the facing surface 40 of the positive electrode 24 without being oxidized, even when the positive electrode 24 is operated at a high voltage, such as at a voltage greater than about 5 V. The aliphatic polyester can provide the gel polymer electrolyte 26 with a voltage greater than about 5 V, optionally greater than about 5.5 V, optionally greater than about 5.6 V, or optionally greater than about 5.7 V vs. Li / Li + The aliphatic polyester can provide the gel polymer electrolyte 26 with an oxidation potential of less than 0 V vs. Li / Li + In addition, the aliphatic polyester is formulated to provide a gel polymer electrolyte 26 with high ionic conductivity. For example, the aliphatic polyester can provide the gel polymer electrolyte 26 with an ionic conductivity of greater than or equal to about 6 millisiemens / cm (mS / cm) at 60 degrees Celsius (° C.), optionally greater than or equal to about 7 mS / cm, optionally greater than or equal to about 8 mS / cm, or optionally greater than or equal to about 8.5 mS / cm.

[0085] The aliphatic polyester may include an aliphatic polycarbonate, an aliphatic polylactone, or a combination thereof. A polycarbonate is a polymer having a carbonate group (—O—(C=O)—O—) on its main chain. A polylactone is a polymer having an ester group (—C(=O)—O—) on its main chain.

[0086] For example, the aliphatic polyester may comprise an aliphatic polycarbonate comprising a polycarbonate having the formula -O-(C=O)-OR 1 -repeating monomer units, wherein R 1 is a substituted or unsubstituted divalent hydrocarbon group having the following structure (1):

[0087]

[0088] Additionally or alternatively, the aliphatic polyester may comprise an aliphatic polylactone comprising a polyol having the formula -O-(C=O)-R 2 -repeating monomer units, wherein R 2 is a substituted or unsubstituted divalent hydrocarbon group having the following structure (2):

[0089]

[0090] A divalent hydrocarbon group (i.e. R 1 and R 2 Examples of ) include divalent acyclic hydrocarbon groups (alkylene groups), divalent cyclic hydrocarbon groups (arylene groups), divalent alicyclic hydrocarbon groups, and combinations thereof. Examples of alkylene groups include C2-C 20 Straight or branched saturated aliphatic groups such as methylene (—CH2—), ethylene (—CH2—CH2—), trimethylene (—CH2—CH2—CH2—), tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, dodecamethylene, ethylethylene, 1,2-dimethylethylene, 1,1-dimethylethylene, propylethylene, 1-ethyl-2-methylethylene, butylethylene, pentylethylene, hexylethylene, and octylethylene, and combinations thereof. Examples of alkylene groups include C2-C 20 Straight or branched unsaturated aliphatic groups, such as alkenylene groups, such as vinylene (-HC=CH-), propenylene (-H2C-CH=CH-), propylene (-CH(CH3)CH2-), and combinations thereof. Examples of arylene groups include styrene, benzylene, phenylene (-C6H4-), 4,4'-diphenylene, 4,4'-biphenylene-2,2-propane, 1,8-naphthylene, and combinations thereof. Examples of divalent alicyclic groups include 1,2-cyclopentylene, 1,3-cyclopentylene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, 1,3-cyclohexane dimethylene, 1,4-cyclohexane dimethylene, cyclohexylethylene, and combinations thereof.

[0091] The aliphatic polyester may be a homopolymer or a copolymer. For example, the aliphatic polyester may comprise a substituted or unsubstituted aliphatic polycarbonate homopolymer, a substituted or unsubstituted aliphatic polylactone homopolymer, or a combination thereof. In embodiments, where the aliphatic polyester comprises a copolymer, the aliphatic polyester may comprise a substituted or unsubstituted polycarbonate-based copolymer, a substituted or unsubstituted polylactone-based copolymer, or a combination thereof. In polycarbonate-based copolymers, the major repeating units in the copolymer chain are those having the formula -O-(C=O)-OR 1 In the polylactone-based copolymers, the main repeating units in the copolymer chain are monomers having the formula -O-(C=O)-R 2 -monomer.

[0092] In an embodiment, the aliphatic polyester may include a poly(ethylene carbonate) (PEC) homopolymer composed of repeating substituted or unsubstituted ethylene carbonate monomer units (-O-(C=O)-O-CH2-CH2-) and / or a PEC-based copolymer mainly comprising repeating substituted or unsubstituted ethylene carbonate monomer units, and other repeating monomer units. In an embodiment, the aliphatic polyester may include a poly(propylene carbonate) (PPC) homopolymer composed of repeating substituted or unsubstituted propylene carbonate monomer units (-O-(C=O)-O-CH(CH3)CH2-) and / or a PPC-based copolymer mainly comprising repeating substituted or unsubstituted propylene carbonate monomer units, and other repeating monomer units. In an embodiment, the aliphatic polyester may include a poly(trimethylene carbonate) (PTMC) homopolymer composed of repeating substituted or unsubstituted trimethylene carbonate monomer units and / or a PTMC-based copolymer mainly comprising repeating substituted and unsubstituted trimethylene carbonate monomer units, and other repeating monomer units. In an embodiment, the aliphatic polyester may comprise a monomeric unit composed of repeating substituted or unsubstituted caprolactone (—O—(C═O)—C6H 10 In an embodiment, the aliphatic polyester may comprise a substituted or unsubstituted poly(propiolactone) (PPL) homopolymer and / or a substituted or unsubstituted PPL-based copolymer. In an embodiment, the aliphatic polyester may comprise a substituted or unsubstituted homopolymer or copolymer of PEC, PPC, PTMC, PCL, PPL, or a combination thereof.

[0093] When a polymer, copolymer, monomer, or divalent hydrocarbon group (i.e., R 1 and R 2) is referred to as being substituted, this means that one or more of its hydrogen atoms are replaced or substituted by another atom or group of atoms referred to as a substituent. Examples of substituents include halogens (e.g., -F, -Cl, -Br, and -I) and straight-chain or branched acyclic or cyclic monovalent hydrocarbon radicals, such as C1–C 10 Straight or branched alkyl (-C n H 2n+1 ), alkenyl (-C n H 2n-1 , wherein n≥2), aryl, alkoxy, aryloxy, carboxyl, acyloxy, and combinations thereof. Straight chain C1–C 10 Examples of alkyl groups include methyl (-CH3), ethyl (-CH2CH3), propyl (-CH2CH2CH3) and butyl (-CH2CH2CH2CH3). 10 Examples of alkyl groups include isopropyl (-CH(CH3)2), isobutyl (-CH2-CH(CH3)2), sec-butyl (-(CH3)CH-CH2-CH3), tert-butyl (-C(CH3)3), isopentyl (-(CH2)2-CH(CH3)2), and tert-pentyl (-(CH3)2C-CH2-CH3). Alkenyl groups are aliphatic hydrocarbon groups having at least one carbon-carbon double bond (C=C) and are formed when a hydrogen atom is removed from an alkenyl group. Examples of alkenyl groups include vinyl (-CH=CH2), allyl (-CH2-HC=CH2), propenyl (-CH=CHCH3), isopropenyl (-(CH3)C=CH2), ethylene (=CH-CH3), isopropylene (=C(CH3)2). Examples of aryl groups include phenyl (-C6H5), benzyl (-CH2-C6H5), benzal (=CH-C6H5), styryl (-CH=CH-C6H5), phenethyl (-CH2-CH2-C6H5), cinnamyl (-CH2-CH=CH-C6H5), diphenylmethyl (-CH(C6H5)2). Alkoxy is an alkyl group bonded to oxygen alone (-OX, wherein X is an alkyl group). Aryloxy is an aryl group bonded to oxygen alone (-OY, wherein Y is an aryl group). Examples of alkoxy include methoxy (-OCH3) and ethoxy (-OCH2CH3). Examples of aryloxy include phenoxy (-OC6H5). Carboxyl is an organic functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group (-C(=O)OH). Acyloxy is represented by the formula -O-(C=O)-X, wherein X is an alkyl group.

[0094] The aliphatic polyester may comprise greater than or equal to about 5%, optionally greater than or equal to about 10% and less than or equal to about 30%, or optionally less than or equal to about 20% by weight of the gel polymer electrolyte 26 .

[0095] The lithium salt is formulated to provide a gel polymer electrolyte 26 having good ionic conductivity, for example, by creating lithium ion transport channels therethrough. The lithium salt may include lithium sulfonyl imide, lithium borate, or a combination thereof. Examples of lithium sulfonyl imide salts include lithium bis(trifluoromethane)sulfonyl imide (LiN(CF3SO2)2) (LiTFSI), lithium bis(fluorosulfonyl)imide (LiN(FSO2)2) (LiFSI), and combinations thereof. Examples of lithium borate salts include lithium bis(oxalato)borate (LiB(C2O4)2) (LiBOB), lithium difluoro(oxalato)borate (LiBF2(C2O4)) (LiDFOB), and combinations thereof. In aspect, the lithium salt may include LiTFSI. The lithium salt may be present in the gel polymer electrolyte 26 at a concentration of greater than or equal to about 3 moles / liter (mol / L), optionally greater than or equal to about 4 mol / L, or optionally greater than or equal to about 5 mol / L and less than or equal to about 10 mol / L, optionally less than or equal to about 8 mol / L, or optionally less than or equal to about 6 mol / L. In an aspect, the lithium salt may be present in the gel polymer electrolyte 26 at a concentration of about 5.5 mol / L. The lithium salt may account for greater than or equal to about 40%, optionally greater than or equal to about 50%, or optionally greater than about 60% and less than or equal to about 90%, optionally less than or equal to about 80%, or optionally less than or equal to about 70% by weight of the gel polymer electrolyte 26. The relatively high lithium salt concentration in the gel polymer electrolyte 26 may help provide a gel polymer electrolyte with high oxidative stability.

[0096] The ionic liquid penetrates the aliphatic polyester and is formulated to provide a gel polymer electrolyte 26 having a combination of good thermal stability, oxidative stability, and ionic conductivity. In addition, the ionic liquid is formulated to have excellent chemical compatibility with the aliphatic polyester. The ionic liquid can help provide a gel polymer electrolyte 26 with good ionic conductivity (e.g., by forming a lithium ion transfer path or bridge therein). The ionic liquid comprises cations and anions. In an embodiment, the cations and anions can be present in the ionic liquid in substantially equimolar amounts and can be referred to as a solvated ionic liquid. The cations of the ionic liquid can include lithium (Li + ) and ethylene glycol dimethyl ether (glycol dimethyl ether), an imidazolium ion, or a combination thereof. Examples of glycol dimethyl ethers include triethylene glycol dimethyl ether (triglyme) and tetraethylene glycol diethyl ether (tetraglyme). In aspects, the cation of the ionic liquid may include lithium (Li + ) and triethylene glycol dimethyl ether complex, lithium (Li + ) and tetraethylene glycol dimethyl ether, or a combination thereof. Examples of imidazolium ions include 1-ethyl-3-methylimidazolium ([Emim] +). The anion of the ionic liquid may include a sulfinate ion, a borate ion, or a combination thereof. Examples of sulfinate ions include bis(fluorosulfonyl)imide (N(FSO2)2 - )(FSI), bis(trifluoromethane)sulfonimide(N(CF3SO2)2 – )(TFSI), and combinations thereof. Examples of borate ions include bis(oxalato)borate (B(C2O4)2 - )(BOB), difluorooxalatoborate (BF2(C2SO4)-)(DFOB), and combinations thereof. In one aspect, the anion of the ionic liquid comprises bis(trifluoromethane)sulfonimide.

[0097] The ionic liquid may comprise greater than or equal to about 5%, optionally greater than or equal to about 10%, or optionally greater than or equal to about 20% and less than or equal to about 50%, optionally less than or equal to about 40%, or optionally less than or equal to about 30% by weight of the gel polymer electrolyte 26.

[0098] The optional support structure can help provide mechanical stability to the gel polymer electrolyte 26, and can include a microporous nonwoven material impregnated, permeated and / or encapsulated in the gel polymer electrolyte 26. For example, the support structure can include a mat of nonwoven fibers. The fibers can include polymers (e.g., polyolefins and / or polyamides), glass, or a combination thereof. For example, the support structure can include a nonwoven fiber mat of polypropylene (PP), polyethylene (PE) and / or polyethylene terephthalate (PET). The support member can have a thickness greater than or equal to about 5 μm, optionally greater than or equal to about 10 μm and less than or equal to about 200 μm, optionally less than or equal to about 100 μm, or optionally less than or equal to about 50 μm.

[0099] The aliphatic polyester, lithium salt, ionic liquid, and optional support structure together may account for greater than or equal to about 90%, optionally greater than or equal to 95%, or optionally greater than or equal to about 99% by weight of the gel polymer electrolyte 26. In an embodiment, the gel polymer electrolyte 26 may be substantially free of an organic solvent, i.e., a non-aqueous aprotic organic solvent. Non-limiting examples of non-aqueous aprotic organic solvents include cyclic carbonates (e.g., ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), fluoroethylene carbonate (FEC), and vinylene carbonate (VC)); linear carbonates (e.g., dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC)); aliphatic carboxylates (e.g., methyl formate, methyl acetate, methyl propionate); lactones (e.g., γ-butyrolactone, γ-valerolactone, and / or δ-valerolactone); nitriles (e.g., succinonitrile, valerolactone, and / or valerolactone); dinitriles and / or adiponitrile); sulfones (e.g., tetramethylene sulfone, ethyl methyl sulfone, vinyl sulfone, phenyl sulfone, 4-fluorophenyl sulfone, benzyl sulfone and / or cyclopentane); aliphatic ethers (e.g., triethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, 1,3-dimethoxypropane, 1,2-dimethoxyethane, 1,2-diethoxyethane and / or ethoxymethoxyethane); cyclic ethers (e.g., 1,4-dioxane, tetrahydrofuran, 2-methyltetrahydrofuran), 1,3-dioxolane); phosphates (e.g., triethyl phosphate and / or trimethyl phosphate); and combinations thereof.

[0100] The negative and positive electrode current collectors 30, 32 are conductive and each provide an electrical connection between the external circuit 36 ​​and its negative and positive electrodes 22, 24. In one aspect, the negative and positive electrode current collectors 30, 32 can be in the form of a non-porous metal foil, a perforated metal foil, a porous metal mesh, or a combination thereof. The negative electrode current collector 30 can be made of copper, nickel or its alloy, stainless steel or other suitable conductive materials. The positive electrode current collector 32 can be made of aluminum (Al) or other suitable conductive materials.

[0101] method

[0102] In the method of manufacturing the battery pack 20, an electrolyte precursor may be prepared. The electrolyte precursor may include a mixture of an ionic liquid and a polymer solution. The ionic liquid may have a composition substantially the same as that of the ionic liquid described above with respect to the gel polymer electrolyte 26. For example, the ionic liquid may include a solvated ionic liquid of lithium bis(trifluoromethane)sulfonyl imide (TFSI)-triethylene glycol dimethyl ether, lithium bis(trifluoromethane)sulfonyl amide (TFSI)-tetraethylene glycol dimethyl ether, 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][TFSI]), or a combination thereof.

[0103] The polymer solution may include an aliphatic polyester and a lithium salt optionally dissolved in a polar aprotic organic solvent. The aliphatic polyester may have substantially the same composition as the aliphatic polyester described above with respect to the gel polymer electrolyte 26. Examples of polar aprotic organic solvents include acetonitrile (ACN) and tetrahydrofuran (THF). In an embodiment, where the polymer solution includes a lithium salt, the lithium salt may have substantially the same composition as the lithium salt described above with respect to the gel polymer electrolyte 26.

[0104] The ionic liquid and the polymer solution can be mixed together so that the resulting electrolyte precursor has a desired mass ratio of lithium salt to aliphatic polyester. For example, the mass ratio of lithium salt to aliphatic polyester (lithium salt: aliphatic polyester) in the electrolyte precursor can be greater than or equal to about 1:1, or optionally greater than or equal to 2:1 and less than or equal to 4:1, or optionally less than or equal to 3:1.

[0105] In an embodiment, the electrolyte precursor may be cast on a substrate to form an electrolyte precursor layer. The polar aprotic organic solvent may then be removed from the electrolyte precursor layer to form a gel polymer electrolyte 26. In an embodiment, the substrate may include a release film, and the gel polymer electrolyte 26 may be removed from the release film and applied to the facing surface 38 of the negative electrode 22 or the facing surface 40 of the positive electrode 24. In an embodiment, the substrate may include the negative electrode 22 or the positive electrode 24, and the electrolyte precursor may be allowed to penetrate the pores of the negative electrode 22 or the positive electrode 24 before removing the polar aprotic organic solvent therefrom.

[0106] In embodiments, where the gel polymer electrolyte 26 includes a support structure, the substrate may include the support structure and may be immersed in the electrolyte precursor so that the support structure is impregnated, infiltrated and / or encapsulated in the electrolyte precursor. The polar aprotic organic solvent may then be removed from the electrolyte precursor layer to form the gel polymer electrolyte 26 including the support structure.

[0107] The foregoing description is merely exemplary and is absolutely not intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be limited thereto, because after studying the drawings, the specification and the following claims, other modifications will become apparent. It should be understood that one or more steps in the method may be implemented in different orders (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more features described with respect to any embodiment of the present disclosure may be implemented in any other embodiment and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the embodiments are not mutually exclusive, and the mutual replacement of one or more embodiments is still within the scope of the present disclosure.

[0108] The terms used herein are intended to be limited only for the purpose of describing exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "one" and "the" used herein are intended to also include plural forms. The terms "comprising", "including" and "having" are inclusive, and therefore specify the presence of specified features, elements, compositions, steps, integers, operations and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their combinations. Although the open terms "comprising", "including" and "having" should be understood as non-limiting terms for describing and requesting the various embodiments described herein, in some aspects, these terms are understood as more restrictive and constraining terms, such as "consisting of..." or "consisting essentially of..." Therefore, for any given embodiment of a composition, material, component, element, ingredient, feature, integer, operation and / or method step, the present disclosure also clearly includes an embodiment consisting of or essentially consisting of these enumerated compositions, materials, components, elements, ingredients, features, integers, operations and / or method steps. In the case of “consisting of,” the alternative embodiment does not include any additional compositions, materials, components, elements, ingredients, features, integers, operations and / or method steps, while in the case of “consisting essentially of,” such an embodiment does not include any additional compositions, materials, components, elements, ingredients, features, integers, operations and / or method steps that substantially affect the basic and novel characteristics, but may include any compositions, materials, components, elements, ingredients, features, integers, operations and / or method steps that do not substantially affect the basic and novel characteristics in the embodiment.

[0109] Any method steps, methods, and operations described herein are not to be construed as necessarily requiring their performance in the order discussed or illustrated, unless expressly specified as an order of performance. It is also to be understood that additional or alternative steps may be used unless otherwise specified.

[0110] When a component, element, or layer is referred to as being "on," "engaged," "connected," or "coupled" to another element or layer, it may be directly on, directly engaged, connected, or coupled to, or there may be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly engaged," "directly connected," or "directly coupled" to another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). The term "and / or" as used herein includes a combination of one or more related enumerated items.

[0111] Although the terms first, second, third, etc. may be used in this article to describe various steps, elements, components, regions, layers and / or sections, unless otherwise specified, these steps, elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish a step, element, component, region, layer or section from another step, element, component, region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other ordinal terms do not imply order or sequence when used in this article. Therefore, the first step, element, component, region, layer or section discussed below can be referred to as the second step, element, component, region, layer or section without departing from the teaching of exemplary embodiments.

[0112] For ease of description, spatially or temporally relative terms such as "front", "rear", "inside", "outside", "lower", "below", "lower", "upper", etc. may be used herein to describe the relationship of one element or component to another element or component as shown in the drawings. The spatially or temporally relative terms are intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the drawings.

[0113] Throughout this disclosure, numerical values ​​represent approximate measurements or range limits, and include slight deviations from given values ​​and embodiments that have approximately the listed values ​​as well as embodiments that have exactly the listed values. In addition to the examples provided at the end of the specific embodiments, all numerical values ​​of parameters (such as amounts or conditions) in this specification should be understood to be modified by the term "about" in all cases, regardless of whether "about" actually appears before the numerical value. The numerical values ​​of the parameters in the attached claims should be understood to be modified by the term "about" only when the term "about" appears before the numerical value. "Approximately" means that the specified numerical value allows a certain slight imprecision (close to the accuracy of the value; approximately or reasonably close to the value; almost). If the imprecision provided by "approximately" is not understood in this ordinary sense in the art, "approximately" used herein at least refers to changes that may be caused by ordinary methods of measuring and using such parameters. For example, "approximately" may include changes of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in some aspects, optionally less than or equal to 0.1%. Additionally, disclosure of ranges includes disclosure of all values ​​within the entire range and further subdivided ranges, including endpoints and subranges given within those ranges.

[0114] As used herein, unless otherwise indicated, the terms "composition" and "material" are used interchangeably to refer generally to materials that contain at least a preferred chemical component, element, or compound, but may also contain additional elements, compounds, or substances, including trace impurities. An "X-based" composition or material generally refers to a composition or material in which "X" is the single largest component of the composition or material on a weight percent (%) basis. This can include compositions or materials having greater than 50% by weight of X, and can also include compositions or materials having less than 50% by weight of X, as long as X is the single largest component of the composition or material based on its total weight. When a composition or material is referred to as being "substantially free" of a substance, the composition or material may contain less than 5%, optionally less than 3%, optionally less than 1%, or optionally less than 0.1% by weight of the substance.

[0115] As used herein, the term "metal" may refer to a pure elemental metal, or to an alloy of an elemental metal and one or more other metals or nonmetallic elements, referred to as "alloying" elements. Alloying elements may be selected to impart certain desirable properties to the alloy that are not exhibited by the base metal element.

Claims

1. A battery pack for circulating lithium ions, the battery pack comprising: Negative electrode; a positive electrode spaced apart from the negative electrode and comprising a high voltage electroactive material configured to undergo lithium intercalation and deintercalation; and A gel polymer electrolyte disposed between the negative electrode and the positive electrode and configured to provide a lithium ion conductive medium between the negative electrode and the positive electrode, the gel polymer electrolyte comprising: Aliphatic polyesters comprising substituted or unsubstituted poly(ethylene carbonate) (PEC), A lithium salt comprising lithium sulfonimide, lithium borate, or a combination thereof, and An ionic liquid comprising substantially equimolar amounts of cations and anions, wherein the cations include lithium (Li + ) and ethylene glycol dimethyl ether, an imidazolium ion, or a combination thereof, and the anion includes a sulfinate ion, a borate ion, or a combination thereof.

2. The battery according to claim 1, wherein the substituted or unsubstituted PEC comprises a PEC homopolymer composed of repeating substituted or unsubstituted ethylene carbonate monomer units, a PEC-based copolymer mainly comprising repeating substituted or unsubstituted ethylene carbonate monomer units, or a combination thereof.

3. The battery pack according to claim 1, wherein the aliphatic polyester further comprises an aliphatic polycarbonate, an aliphatic polylactone, or a combination thereof, the aliphatic polycarbonate comprising a 1 - the main repeating monomer unit, wherein R 1 is a substituted or unsubstituted divalent hydrocarbon group, the aliphatic polylactone comprises a 2 - the main repeating monomer unit, wherein R 2 is a substituted or unsubstituted divalent hydrocarbon group.

4. The battery of claim 1, wherein the aliphatic polyester further comprises substituted or unsubstituted poly(propylene carbonate) (PPC), poly(trimethylene carbonate) (PTMC), polycaprolactone (PCL), poly(propiolactone) (PPL), or a combination thereof.

5. The battery of claim 1, wherein the lithium salt comprises lithium bis(trifluoromethane)sulfonyl imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), or a combination thereof.

6. The battery pack according to claim 1, wherein the aliphatic polyester accounts for greater than or equal to about 5% and less than or equal to about 30% by weight of the gel polymer electrolyte, the lithium salt accounts for greater than or equal to about 40% and less than or equal to about 90% by weight of the gel polymer electrolyte, and the ionic liquid accounts for greater than or equal to about 5% and less than or equal to about 50% by weight of the gel polymer electrolyte.

7. The battery pack according to claim 1, wherein the lithium salt comprises lithium bis(trifluoromethane)sulfonyl imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), or a combination thereof, and the cation of the ionic liquid comprises lithium (Li + ) and triethylene glycol dimethyl ether, and wherein the anion of the ionic liquid comprises bis(fluorosulfonyl)imide (FSI), bis(trifluoromethane)sulfonylimide (TFSI), bis(oxalato)borate (BOB), difluorooxalatoborate (DFOB), or a combination thereof.

8. The battery of claim 1, wherein the gel polymer electrolyte has a relative humidity of greater than or equal to about 5.5 volts vs. Li / Li + oxidation potential.

9. The battery of claim 1, wherein the gel polymer electrolyte has an ionic conductivity greater than or equal to about 8.5 mS / cm at 60 degrees Celsius (°C).

10. The battery pack according to claim 1, wherein the gel polymer electrolyte further comprises: A carrier comprising a microporous nonwoven material impregnated with and encapsulated in the gel polymer electrolyte.

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