Rechargeable lithium metal cell

Abstract

The present invention provides a rechargeable lithium metal cell comprising: an anode containing lithium metal; a cathode containing a high-voltage cathode material; and a plurality of lithium conductive layers interposed between the anode and the cathode, wherein the lithium conductive layer comprises a solid polymer anode liquid layer adjacent to the anode and one or more further electrolyte layers separating the polymer anode liquid layer from the cathode, and the solid polymer anode liquid layer comprises (i) a block copolymer comprising at least one hydrophobic nonionic block and at least one ionic block, and (ii) a lithium salt, and the solid polymer anode liquid layer has at least two glass transition temperature (Tg) values.

Description

[Technical Field]

[0001] Priority cross-referencing This application claims priority to Australian Provisional Patent Application No. 2023901163, filed on 19 April 2023, the contents of which should be deemed incorporated herein by reference.

[0002] The present invention relates to a rechargeable lithium metal cell comprising a lithium metal anode, a high-voltage cathode, and a plurality of lithium conductive layers interposed between the anode and the cathode. The lithium conductive layer comprises a solid polymer anode liquid layer adjacent to the anode and one or more further electrolyte layers separating the solid polymer anode liquid layer from the cathode. The solid polymer anode liquid layer comprises a block copolymer including hydrophobic nonionic blocks and ionic blocks, and a lithium salt. The present invention further relates to a method for cycling a rechargeable lithium metal cell; a method for manufacturing a rechargeable lithium metal cell; and a cathode half cell for manufacturing a rechargeable lithium metal cell. [Background technology]

[0003] Rechargeable lithium batteries are now ubiquitous in society. However, for many applications, it is desirable to have a higher energy density than commercially available lithium-ion batteries. In principle, significant improvements can be achieved by replacing the graphite anode with an anode material that has a higher specific capacity. Specific capacity of 3,860 mAh.g -1 Lithium metal is an ideal anode material for high-energy-density batteries. However, the development of commercially available lithium metal batteries has been hampered by significant challenges, including poor cycleability and safety risks. In particular, lithium metal cells are susceptible to cell failure caused by dendrite growth on the anode over multiple charge-discharge cycles, and to insufficient Coulomb efficiency and capacity degradation due to reactions between lithium metal and electrolytes or water.

[0004] One approach to mitigate these problems is to replace conventional liquid electrolytes with solid electrolytes. Solid polymer electrolytes offer a particularly promising approach to improving the overall electrochemical performance and safety of lithium metal due to their good shape flexibility, suppression of dendrite growth, elimination of leakage problems, and lower flammability compared to liquid electrolytes.

[0005] Block copolymer-based electrolytes have recently attracted attention due to their highly customizable chemical properties, allowing for a good balance between competing requirements in electrolyte composition: (i) a modulus high enough to suppress dendrite growth, (ii) good chemical and electrochemical stability in contact with the lithium metal anode, and (iii) sufficient ionic conductivity for satisfactory cell performance. Suitable block copolymers generally include hydrophobic and polar blocks that undergo phase separation in the solid state, providing a composite-like electrolyte structure comprising a network of interconnected mechanically robust hydrophobic domains and polar domains where lithium ion conduction can occur.

[0006] Solid polymer electrolytes containing such block copolymers are disclosed, for example, in International Publication No. 2019 / 084623 and have been successfully used in simple low-voltage cells (lithium iron phosphate cathode | block copolymer electrolyte | Li metal anode).

[0007] Another method to increase the energy density of a lithium battery is to increase the operating voltage. This creates a large electrochemical potential difference with respect to the anode when fully charged, for example, Li / Li + The selection of a cathode material having an electrochemical potential difference of at least 4V, but preferably significantly higher, is required. Examples of such materials include LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM622) and LiNi 0.8 Co 0.1 Mn 0.1include nickel-rich layered oxides such as O2 (NCM811), which have an electrochemical potential of 4.3 V or higher with respect to Li / Li + and have an electrochemical potential of 4.3 V or higher with respect to Li / Li.

[0008] Therefore, a particularly desirable high-energy cell combines a lithium metal anode with a cathode containing a high-voltage cathode material. However, such a combination still addresses anode-related issues (described above) and must be compatible with the high-voltage cathode over the required life of the cell, imposing a stringent set of requirements on the electrolyte while providing satisfactory lithium conductivity during cycling.

[0009] Therefore, there is a continuing need for rechargeable lithium metal cells that at least partially address one or more of the above disadvantages or provide useful alternatives.

[0010] References in this specification to patent documents or other items given as prior art should not be construed as an admission that the document or item was known or that the information it contains was part of the common general knowledge at the priority date of any of the claims. SUMMARY OF THE INVENTION

[0011] The inventors have now developed a high-energy-density lithium metal cell in which the lithium metal anode and high-voltage cathode are separated by multiple lithium-conductive electrolyte layers in a multilayer electrolyte structure. The electrolyte layers include a solid polymer anode liquid layer adjacent to the anode, the composition of which includes a block copolymer comprising hydrophobic nonionic blocks and ionic blocks combined with lithium salts. One or more further electrolyte layers separate the solid polymer anode liquid layer from the cathode. This type of cell has been shown to enable long-term cycling with good Coulomb efficiency and capacity maintenance at charge cutoff voltages of 4.3 or 4.5 V. While we do not wish to be limited by any theory, it is suggested that the separation of the solid polymer anode liquid layer from the cathode is important to avoid or to an acceptable extent the chemical and electrochemical oxidative decomposition processes that would occur during cell cycling if the solid polymer anode liquid layer were in direct contact with the high-voltage cathode material.

[0012] The inventors have shown that various different solid and / or liquid electrolyte spacer layers can be compatible with a high-voltage cathode and a solid polymer anode liquid layer to provide a high-energy cell with excellent cycling performance. In some preferred embodiments, one or more (or each of) further electrolyte layers contain a liquid organic electrolyte component, such as a free ionic liquid. For example, the liquid organic electrolyte component may be present as an additive in the solid electrolyte composition. While we do not wish to be limited by any theory, it is proposed that the liquid organic electrolyte component facilitates the movement of lithium ions and / or softens the electrolyte composition, and therefore promotes lithium conductivity through the lithium conductive layer in which it is present and / or across the interface between that layer and adjacent layers in the cell.

[0013] According to a first aspect, the present invention provides a rechargeable lithium metal cell comprising: an anode containing lithium metal; a cathode containing a high-voltage cathode material; and a plurality of lithium conductive layers interposed between the anode and the cathode, wherein the lithium conductive layer comprises a solid polymer anode liquid layer adjacent to the anode and one or more further electrolyte layers separating the polymer anode liquid layer from the cathode, and the solid polymer anode liquid layer comprises (i) a block copolymer comprising at least one hydrophobic nonionic block and at least one ionic block, and (ii) a lithium salt, and the solid polymer anode liquid layer has at least two glass transition temperature (Tg) values.

[0014] In some embodiments, the high-voltage cathode material is at least 4.1V vs Li / Li + , or at least 4.25V vs Li / Li + , or at least 4.35V vs Li / Li + For example, at least 4.5V vs Li / Li + It has an electrochemical potential of .

[0015] In some embodiments, the high-voltage cathode material comprises one or more metals selected from nickel, cobalt, and manganese.

[0016] In some embodiments, the high-voltage cathode material is selected from the group consisting of nickel-rich layered oxides, lithium-rich layered oxides, high-voltage spinel oxides, and high-voltage polyanionic compounds.

[0017] In some embodiments, the high-voltage cathode material is LiNi x Co y M z It is a nickel-rich layered oxide in the form of O2, where M is selected from Mn, Al, and combinations thereof, and x+y+z=1 and x≧0.6.

[0018] In some embodiments, the rechargeable lithium metal cell retains at least 90% of its capacity after 100 charge-discharge cycles performed at 0.2C and 50°C with a charge cutoff voltage of at least 4.25V, e.g., at least 4.35V, e.g., at least 4.5V. In some embodiments, the rechargeable lithium metal cell retains at least 85% of its capacity after 100 charge-discharge cycles performed at 0.2C and 25°C with a charge cutoff voltage of at least 4.25V, preferably at least 4.35V, more preferably at least 4.5V, e.g., 4.6V.

[0019] In some embodiments, the molecular weight of the block copolymer is greater than 50,000 g / mol, for example, greater than 100,000 g / mol. In some embodiments, the molecular weight of at least one hydrophobic nonionic block of the block copolymer is greater than its confounding molecular weight and may be greater than 18,000 g / mol, for example, greater than 25,000 g / mol.

[0020] In some embodiments, the block copolymer is a triblock copolymer in the form of ABA, where each A is a hydrophobic nonionic block and B is an ionic block.

[0021] In some embodiments, at least one hydrophobic nonionic block comprises a polymerization residue of a hydrophobic monomer, and at least one ionic block comprises a polymerization monomer residue having (a) a pendant organic ionic liquid cation having a counter anion, (b) a pendant anionic moiety, a pendant anionic moiety having a counter cation, or (c) a combination thereof, covalently bonded thereto.

[0022] In some embodiments, at least one ionic block comprises a polymerized monomer residue covalently bonded to a pendant organoionic liquid cation, such as an imidazolium, pyrrolidinium, phosphonium, pyridinium, and ammonium cation, selected from, for example, a dialkylimidazolium cation.

[0023] In some embodiments, the solid polymer anode liquid layer contains at least 10% by weight of a lithium salt.

[0024] In some embodiments, the solid polymer anode liquid layer further comprises an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof.

[0025] In some embodiments, the solid polymer anode liquid layer has a thickness of less than 50 μm, for example less than 20 μm, for example 0.5 to 10 μm.

[0026] In some embodiments, the solid polymer anode liquid layer is a coating on the anode.

[0027] In some embodiments, the polymer anode liquid layer is separated from the cathode by a separation distance of less than 100 μm, for example less than 50 μm, for example in the range of 15 to 45 μm.

[0028] In some embodiments, at least one of the further electrolyte layers contains an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof. In some embodiments, at least two of the further electrolyte layers contain an organic electrolyte. In some embodiments, each of the further electrolyte layers contains an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof.

[0029] In some embodiments, at least one of the further electrolyte layers contains a free ionic liquid. In some embodiments, at least two of the further electrolyte layers contain a free ionic liquid. In some embodiments, each of the further electrolyte layers contains a free ionic liquid. The free ionic liquid may be present in an amount of at least 1% by weight, e.g., at least 2% by weight, or at least 5% by weight, e.g., at least 10% by weight, relative to the total weight of the further electrolyte layers(s) present.

[0030] In some embodiments, one or more additional electrolyte layers include a solid cathode liquid layer adjacent to the cathode, the solid cathode liquid layer being selected from a solid polymer cathode liquid layer and a solid inorganic electrolyte layer.

[0031] In some embodiments, the solid cathode liquid layer adjacent to the cathode is a solid inorganic electrolyte layer comprising a lithium-containing inorganic material selected from garnet, NASICON-type materials, sulfides, and perovskites.

[0032] In some embodiments, the solid polymer cathode liquid layer adjacent to the cathode is a solid polymer cathode liquid layer.

[0033] In some embodiments, the solid polymer cathode liquid layer contains a fluorinated polymer. The fluorinated polymer may contain a carbon chain skeleton. The fluorinated polymer may also contain polymerized vinylidene difluoride units. In some embodiments, the fluorinated polymer is an ionic fluorinated polymer. In some embodiments, the fluorinated polymer is an ionic fluorinated polymer containing a carbon chain skeleton and pendant ionic groups covalently bonded to the carbon chain skeleton.

[0034] In some embodiments, the pendant ion group comprises a plurality of organic ionic liquid cations. The organic ionic liquid cations may be selected from the group consisting of quaternary ammonium, imidazolium, benzimidazolium, pyrrolidinium, pyrrolium, indium, carbazolium, pyridinium, quinolinium, piperidinium, piperadinium, phosphonium, and sulfonium cations. In some embodiments, the organic ionic liquid cation comprises or consists of a quaternary ammonium cation. In some embodiments, the pendant ion group comprises a plurality of polymerization monomer residues, each polymerization monomer residue covalently bonded to the organic ionic liquid cation. In some embodiments, the pendant ion group is produced by graft polymerization of an ionic monomer onto a carbon chain skeleton, the ionic monomer comprising (i) a polymerizable ethylenically unsaturated functional group and (ii) an organic ionic liquid cation.

[0035] In some embodiments, the solid polymer cathode liquid layer comprises a lithium salt and at least one selected from a free ionic liquid and a poly(alkylene oxide).

[0036] In some embodiments, one or more additional electrolyte layers include an intermediate electrolyte layer interposed between the solid polymer anode liquid layer and the solid cathode liquid layer, for example, between the solid polymer anode liquid layer and the solid polymer cathode liquid layer. The intermediate electrolyte layer can be selected from a solid polymer electrolyte layer, a solid inorganic electrolyte layer, and a liquid electrolyte layer. The intermediate electrolyte layer can facilitate lithium ion conduction between the solid polymer cathode liquid layer and the solid polymer anode liquid layer during use.

[0037] In some embodiments, the intermediate electrolyte layer comprises a lithium-conductive polymer composition comprising (i) an ionic fluorinated polymer having a carbon chain skeleton and pendant ion groups covalently bonded to the carbon chain skeleton, (ii) a lithium salt, and optionally (iii) a free ionic liquid.

[0038] In some embodiments, the intermediate electrolyte layer includes a porous separator permeated with a liquid electrolyte containing a lithium-conductive polymer composition or a lithium salt.

[0039] In some embodiments, the intermediate electrolyte layer includes a solid inorganic electrolyte layer containing mobile lithium ions. The solid inorganic electrolyte layer may include a lithium-containing inorganic material selected from garnet, NASICON-type materials, sulfides, and perovskites.

[0040] In some embodiments, one or more additional electrolyte layers include a porous separator permeated with a liquid electrolyte containing a lithium salt. The liquid electrolyte may include a free ionic liquid.

[0041] In some embodiments, one or more additional electrolyte layers include a solid inorganic electrolyte layer containing mobile lithium ions. The solid inorganic electrolyte layer may contain a lithium-containing inorganic material selected from garnet, NASICON-type materials, sulfides, and perovskites.

[0042] In some embodiments, one or more further electrolyte layers include (i) a block copolymer comprising at least one hydrophobic nonionic block and at least one ionic block, and (ii) a second polymer anode liquid layer comprising a lithium salt, wherein the second polymer anode liquid layer is adjacent to the solid polymer anode liquid layer and spaced apart from the cathode.

[0043] In some embodiments, the further electrolyte layer includes (i) a solid cathode liquid layer adjacent to the cathode according to any embodiment disclosed herein, (ii) a second polymer anode liquid layer adjacent to the solid polymer anode liquid layer according to any embodiment disclosed herein, and (iii) an intermediate electrolyte layer interposed between the solid polymer anode liquid layer and the solid cathode liquid layer according to any embodiment disclosed herein. Thus, the intermediate electrolyte layer may be directly adjacent to both the solid cathode liquid layer and the second polymer anode liquid layer (i.e., sandwiched between these layers).

[0044] In some embodiments, each lithium conductive layer is a solid electrolyte.

[0045] According to a second aspect, the present invention provides a method for cycling a rechargeable lithium metal cell according to any embodiment of the first aspect, comprising one or more cycles of (i) charging the rechargeable lithium metal cell to a charge cutoff voltage of at least 4.1V, and (ii) discharging the rechargeable lithium metal cell.

[0046] In some embodiments, the charge cutoff voltage is at least 4.25V, for example, at least 4.35V, for example, at least 4.5V.

[0047] According to a third aspect, the present invention provides a method for manufacturing a rechargeable lithium metal cell according to any embodiment of the first aspect, comprising: providing an anode half cell including the anode; providing a cathode half cell including the cathode; and assembling the anode half cell and the cathode half cell to provide a rechargeable lithium metal cell having the plurality of lithium conductive layers interposed between the anode and the cathode.

[0048] In some embodiments, before assembling the anode half-cell and cathode half-cell, the anode half-cell includes a solid polymer anode liquid layer bonded to the anode.

[0049] In some embodiments, providing an anode half-cell involves generating a solid polymer anode liquid layer bonded to the anode by a coating technique selected from slot die coating, comma coating, or melt extrusion.

[0050] In some embodiments, the cathode half-cell includes a second polymer anode liquid layer containing a block copolymer and a lithium salt as an outer layer, and assembling the anode half-cell and cathode half-cell involves bonding the solid polymer anode liquid layer to the second polymer anode liquid layer.

[0051] In some embodiments, the cathode half-cell includes a solid cathode liquid layer adjacent to the cathode, such as a solid polymer cathode liquid layer.

[0052] According to a fourth aspect, the present invention provides a cathode half-cell comprising a cathode containing a high-voltage cathode material, the cathode being supported on a current collector; a solid polymer anode liquid layer; and one or more further electrolyte layers separating the solid polymer anode liquid layer from the cathode, wherein the solid polymer anode liquid layer comprises (i) a block copolymer comprising at least one hydrophobic nonionic block and at least one ionic block, and (ii) a lithium salt, and the solid polymer anode liquid layer having at least two glass transition temperature (Tg) values.

[0053] In some embodiments, one or more additional electrolyte layers include a solid cathode liquid layer adjacent to the cathode, such as a solid polymer cathode liquid layer. The solid polymer cathode liquid layer may contain a fluorinated polymer. The fluorinated polymer may contain a carbon chain skeleton. The fluorinated polymer may contain polymerized vinylidene difluoride units. The fluorinated polymer may be an ionic fluorinated polymer.

[0054] It will be understood that other features of the present invention according to the third and fourth aspects may be as disclosed herein with respect to the first aspect.

[0055] Where the terms “comprise,” “comprises,” and “comprising” are used herein (including in the claims), they should be interpreted as identifying the described features, integers, processes, or components, but not as excluding the existence of one or more other features, integers, processes, or components, or groups thereof.

[0056] Where used herein, terms such as “first,” “second,” and “third” relating to various features of the disclosed apparatus, method, system, etc., are arbitrarily assigned and are intended simply to distinguish two or more such features that the apparatus, method, system, etc., may incorporate into various embodiments. These terms do not, in themselves, indicate a particular orientation or arrangement. Furthermore, it should be understood that the presence of a “first” feature does not imply the presence of a “second” feature, nor does the presence of a “second” feature imply the presence of a “first” feature, and so on.

[0057] Further aspects of the present invention are shown below in the detailed description of the present invention.

[0058] Embodiments of the present invention are illustrated herein by reference only, with reference to the following appended drawings. [Brief explanation of the drawing]

[0059] [Figure 1] A schematic diagram of the rechargeable lithium metal cell according to the present invention is shown. [Figure 2] A rechargeable lithium metal cell according to several embodiments of the present invention is schematically shown, the cell comprising a second polymer anode liquid layer adjacent to a solid polymer anode liquid layer but separated from the cathode by one or more further electrolyte layers. [Figure 3] The following schematic diagram illustrates a rechargeable lithium metal cell according to several embodiments of the present invention, the cell comprising a solid polymer cathode liquid layer adjacent to the cathode and an intermediate electrolyte layer interposed between the solid polymer cathode liquid layer and the solid polymer anode liquid layer. [Figure 4] The present invention schematically illustrates a rechargeable lithium metal cell according to several embodiments, the cell comprising a porous separator permeated with a liquid electrolyte containing a lithium salt, as a further electrolyte layer separating the solid polymer anode liquid layer from the cathode. [Figure 5]The present invention schematically illustrates a rechargeable lithium metal cell according to several embodiments, the cell comprising a solid inorganic electrolyte layer containing mobile lithium ions as a further electrolyte layer separating the solid polymer anode liquid layer from the cathode. [Figure 6] Figure 2 schematically shows the method for manufacturing the rechargeable lithium metal cell. [Figure 7] This is a plot of voltage vs. capacitance when a lithium metal cell containing multiple solid polymer electrolyte layers, as performed in Example 2, was cycled at 0.1C, 0.2C, and 0.5C. [Figure 8] This is a plot of voltage vs. capacitance when a lithium metal cell containing an ionic liquid electrolyte layer was cycled at 0.1C, 0.2C, and 0.5C, as performed in Example 3. [Figure 9] This is a plot of voltage vs. capacitance when a lithium metal cell containing a solid garnet-based electrolyte layer was cycled at 0.1C, 0.2C, and 0.5C, as performed in Example 4. [Figure 10] This is a plot of voltage vs. capacitance when a lithium metal cell containing a solid NASICON-type electrolyte layer was cycled at 0.1C, 0.2C, and 0.5C, as performed in Example 5. [Figure 11] This is a plot of voltage vs. capacitance when a lithium metal cell containing a solid sulfide-based electrolyte layer was cycled at 0.1C, 0.2C, and 0.5C, as performed in Example 6. [Figure 12] This is a plot of voltage vs. capacitance when a lithium metal cell containing a Pilblox-based solid polymer anode liquid layer directly adjacent to the cathode was cycled at 0.1C and 0.2C, as performed in Example 7. [Modes for carrying out the invention]

[0060] The present invention relates to a rechargeable lithium metal cell. The rechargeable lithium metal cell comprises an anode containing lithium metal, a cathode containing a high-voltage cathode material, and a plurality of lithium conductive layers interposed between the anode and the cathode. The lithium conductive layer comprises a solid polymer anode liquid layer adjacent to the anode and one or more further electrolyte layers separating the polymer anode liquid layer from the cathode. The solid polymer anode liquid layer comprises (i) a block copolymer comprising at least one hydrophobic nonionic block and at least one ionic block, and (ii) a lithium salt. The solid polymer anode liquid layer has at least two glass transition temperature (Tg) values.

[0061] Figure 1 schematically shows a rechargeable lithium metal cell 100 according to several embodiments of the present invention. The cell 100 includes a lithium metal anode 102 and a high-voltage cathode 104, which are located on an anode current collector 106 and a cathode current collector 108, respectively. Thus, the cell 100 may be connected to other cells in a battery and / or external circuit via electrical connections to the current collectors. The cell 100 includes a plurality of lithium conductive layers 110 interposed between the anode 102 and the cathode 104. These layers include a solid polymer anode liquid layer 112 adjacent to the anode 102 and one or more further electrolyte layers 114 that separate the polymer anode liquid layer 112 from the cathode 104 by a distance indicated as d1 in Figure 1. The one or more further electrolyte layers 114 may include only a single further electrolyte layer as shown in Figure 1, but may include two or more layers as described below.

[0062] The rechargeable lithium metal cells according to this disclosure, also known as secondary lithium metal cells, may optionally be present in a rechargeable battery in combination with other similar or different rechargeable cells. It will be understood that the rechargeable battery may comprise additional conventional battery components such as hermetic packaging and electrical contacts.

[0063] anode The rechargeable cells disclosed herein contain lithium metal and typically include an anode (also known as a negative electrode) made of lithium metal. Lithium metal has a high specific capacity (3,860 mAh / g). -1 Due to its low electrochemical potential and other factors, it is an ideal anode material for high-energy secondary batteries. However, lithium metal cells are susceptible to failures caused by dendrite growth on the anode over multiple charge-discharge cycles of the cell, as well as insufficient Coulomb efficiency and capacity degradation due to reactions between lithium metal and electrolyte or water. While we do not wish to be limited by any theory, the excellent cycle performance obtained in high-voltage lithium metal batteries configured as disclosed herein is thought to be at least partially attributable to the mitigation of one or more of these anode-related problems.

[0064] The anode may include a layer of metallic lithium having at least sufficient thickness for the required charging capacity of the cell. For example, the anode may include a layer of lithium metal having a thickness of 5 μm to 50 μm, for example, 15 μm to 30 μm. The metallic lithium anode may be located on a current collector, such as a metallic current collector such as copper foil. For example, the anode may include a layer of metallic lithium having a thickness of 5 μm to 50 μm, for example, 10 μm or 20 μm, laminated on a copper foil current collector having a thickness of 5 μm to 50 μm, for example, 10 μm.

[0065] Cathode The rechargeable lithium metal cells disclosed herein include a cathode (also known as an anode) comprising a high-voltage cathode material. As used herein, the cathode material of a lithium-based cell is an electroactive material of the cathode that can take up lithium ions by a reduction half-reaction during the discharge of the cell.

[0066] Commercial lithium batteries operating with liquid organic carbonate electrolytes are typically limited to discharge voltages below approximately 4V because the organic electrolyte is susceptible to oxidation at higher voltages. However, the energy density of a cell corresponds to the product of its specific capacity (charge capacity per unit mass) and its operating voltage (the difference in electrochemical potential between the cathode and anode during discharge). Therefore, it is desirable to develop cells that can operate stably at higher voltages by using a suitable high-voltage cathode material with good specific capacity.

[0067] In the context of lithium metal cells, high-voltage cathode materials, when fully charged, exhibit a large electrochemical potential difference relative to the lithium metal anode, particularly Li / Li + It has an electrochemical potential of more than 4V relative to Li / Li. In some embodiments of the cells disclosed herein, the high-voltage cathode material has at least 4.1V vs Li / Li + , or at least 4.25V vs Li / Li + For example, at least 4.35V vs Li / Li + For example, at least 4.5V vs Li / Li + It has an electrochemical potential of .

[0068] In some embodiments, the high-voltage cathode material is at least 150 mA.hg -1 For example, at least 200mA.hg -1 It has a specific capacity of .

[0069] In some embodiments, the high-voltage cathode material comprises one or more metals selected from nickel, cobalt, and manganese. For example, the high-voltage cathode material may be a nickel-rich layered oxide, a lithium-rich layered oxide, a high-voltage spinel oxide, or a high-voltage polyanion compound.

[0070] A suitable nickel-rich layered oxide is LiNi x Co y M zIt may also be in the form of O2, where M is selected from Mn, Al, and combinations thereof, and x+y+z=1 and x≧0.6. A specific example of a suitable nickel-rich layered oxide is LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM622) and LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811) is one example, and these are suitable for 4.3V and 4.6V lithium metal cells, respectively.

[0071] Suitable lithium-rich layered oxides are Li 1+x M 1-x It may take the form of O2 (wherein M is selected from Mn, Ni, and Co). A suitable example of a high-voltage spinel oxide is LiNi 0.5 Mn 1.5 It is O4.

[0072] The cathode contains a sufficient amount of high-voltage cathode material to provide the required charging capacity of the cell. In some embodiments, the cathode has a capacity of at least 1.5 mAh.cm². -2 For example, at least 2mAh.cm -2 It includes a high-voltage cathode of a certain quantity.

[0073] The high-voltage cathode material is preferably in the form of particulate matter. The cathode may further contain other components such as conductive additives and polymer binders. Conductive additives, also typically in particulate form, are included to improve the conductivity of the cathode material and its electrical contact with the current collector. The conductive additives may be carbon-based fine particles such as carbon black.

[0074] The binder may be any polymer material that, in principle, possesses sufficient thermal and chemical stability to withstand the chemical environment and electrochemical processes within the cell, particularly stability against oxidation by high-voltage cathode materials, and can bond the cathode's particulate components together to the current collector. A common polymer binder used in lithium-ion batteries is polyvinylidene fluoride (PVDF), which is preferred due to its high thermal and electrochemical stability and excellent adhesive properties. However, non-conductive binders can act as insulators against ion conduction. Therefore, in some embodiments, the binder is a conductive binder, particularly an ionic polymer binder. In some embodiments, the binder includes an ionic fluorinated polymer. In some embodiments, the binder includes an ionic fluorinated polymer containing pendant ionic groups covalently bonded to the polymer's carbon chain skeleton, for example, of the type described in more detail below in relation to a solid polymer cathode liquid layer. Such binders have been found suitable for strengthening the particulate cathode components while providing excellent ion conductivity and oxidation resistance by high-voltage cathode materials.

[0075] The cathode may include a layer of particulate matter components, including high-voltage cathode material and conductive additives, if present, having a thickness and cathode material load density suitable for providing the required charging capacity of the cell. The cathode layer may be present on a current collector, such as a metal current collector such as aluminum foil. The particulate matter components may be held together on the current collector by a polymer binder. Nevertheless, the resulting composite of particulate matter components and binder may be porous. Advantageously, the porous structure of the cathode may allow the penetration of a solid polymer cathode liquid composition into the cathode, as described below.

[0076] Lithium conductive layer The rechargeable lithium metal cell disclosed herein includes a plurality of lithium conductive layers interposed between the anode and the cathode. The role of the lithium conductive layers is, collectively, to electrically isolate the anode from the cathode and to facilitate the easy transport of lithium ions between the anode and cathode (low internal resistance) during the cell cycle, while avoiding or to an acceptable extent undesirable processes that would lead to capacity degradation or battery failure, such as irreversible redox reactions of electrolyte components at the cathode or anode or non-uniform lithium electroplating at the anode.

[0077] The lithium conductive layer comprises a solid polymer anode liquid layer adjacent to the anode and one or more further electrolyte layers that separate the polymer anode liquid layer from the cathode. In some embodiments, the polymer anode liquid layer is separated from the cathode by less than 100 μm, e.g., less than 50 μm, e.g., in the range of 15 to 45 μm. Such separation distances can avoid or tolerably limit undesirable reactions between the polymer anode liquid layer and the cathode while ensuring that the internal resistance of the cell remains unacceptably low.

[0078] In some embodiments, each lithium conductive layer is a solid electrolyte (SSE). Solid electrolytes, including but not limited to polymer solid electrolytes, can provide improved overall electrochemical performance and safety of lithium-based devices due to their good shape flexibility, elimination of leakage problems, and lower flammability compared to liquid electrolytes. However, in other embodiments, at least one lithium conductive layer may contain a liquid electrolyte impregnated, for example, through an inert porous separator.

[0079] Each lithium conductive layer may contain mobile lithium ions, typically present in at least one lithium salt in which the anions are not covalently bonded to the polymer structure or other solid-phase components. The same lithium salt may be present in each layer. The presence of mobile lithium ions through the intervening layer between the anode and cathode facilitates lithium transport during cell discharge and charging. Suitable lithium salts are described herein in relation to the solid polymer anode liquid layer and further electrolyte layers.

[0080] In some embodiments, at least one of the lithium conductive layers contains an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof.

[0081] The organic electrolyte (as a pure component, i.e., separated from the other components of the lithium conductive layer) may be liquid at the cell's operating temperature. In some embodiments, the organic electrolyte is liquid at 50°C or room temperature (22°C). Thus, the organic electrolyte can solubilize and move lithium ions during the charging and discharging of the cell. Therefore, the organic electrolyte facilitates lithium conductivity through the interface between the lithium conductive layer in which it exists and / or between that layer and adjacent layers (such as adjacent lithium conductive electrolyte layers).

[0082] A lithium conductive layer (one or more) containing an organic electrolyte can be a solid electrolyte or a liquid electrolyte. Therefore, in a solid electrolyte, the organic electrolyte exists as an additive not covalently bonded to the solid component of the solid electrolyte. While the electrolyte layer as a whole remains solid, the organic electrolyte additive can favorably soften the solid composition, migrate lithium cations into it, and / or promote lithium ion conductivity across the interface with adjacent solid electrolyte layers or electrodes (i.e., reduce interfacial resistance). Thus, the organic electrolyte component can favorably improve the performance of a cell in which all electrolyte layers are solid electrolytes.

[0083] In embodiments where the solid electrolyte is a solid polymer electrolyte layer, the solid polymer anode liquid layer may exhibit at least one glass transition temperature (Tg) value corresponding to the polymer component of the electrolyte composition. Therefore, the amount of organic electrolyte may be limited by essential conditions to avoid dissolution or excessive plasticization of the polymer component.

[0084] In some embodiments, one or more of the lithium conductive layers are solid electrolytes, such as solid polymer electrolytes, and contain an organic electrolyte in an amount of less than 50% by weight, for example, about 1% to about 50% by weight, for example, about 5% to about 35% by weight, or about 10% to about 30% by weight, relative to the total weight of the solid electrolyte.

[0085] In some embodiments, as described in more detail below, the liquid layer of the solid polymer anode adjacent to the anode contains an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof.

[0086] In some embodiments, at least one of the further electrolyte layers (separating the polymer anode liquid layer from the cathode) comprises an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof. In some embodiments, at least one of the further electrolyte layers (separating the polymer anode liquid layer from the cathode) comprises a free ionic liquid. The free ionic liquid may be present in an amount of at least 1% by weight, e.g., at least 2% by weight, or at least 5% by weight, e.g., at least 10% by weight, relative to the total weight of the further electrolyte layers (which may be present).

[0087] In some embodiments, at least one of the solid polymer anode liquid layer adjacent to the anode and a further electrolyte layer (separating the polymer anode liquid layer from the cathode) each contains an organic electrolyte independently selected from free ionic liquids, polar aprotic molecular compounds and combinations thereof. In some embodiments, at least one of the solid polymer anode liquid layer adjacent to the anode and a further electrolyte layer (separating the polymer anode liquid layer from the cathode) each contains a free ionic liquid.

[0088] In some embodiments, each of the further electrolyte layers (separating the polymer anode liquid layer from the cathode) comprises an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof.

[0089] In some embodiments, each lithium conductive layer contains an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof. In some embodiments, each lithium conductive layer contains a free ionic liquid, and optionally the same free ionic liquid.

[0090] As used herein, “free ionic liquid” refers to a low-melting-point organic salt in which neither cations nor anions are covalently bonded to the polymer structure or other solid-phase components. This does not mean that the ionic liquid is present in the liquid electrolyte phase; in fact, free ionic liquids can be mixed into the solid matrix of a solid electrolyte layer to enhance its lithium conductivity. In its pure form, free ionic liquids may have a melting point below 100°C, preferably below room temperature (22°C).

[0091] Certain ionic liquids can be particularly preferred liquid organic electrolytes due to their electrochemical stability in the presence of lithium metal anodes and / or high-voltage cathodes. In some embodiments, the cations of the free ionic liquid are selected from ammonium cations, pyridinium cations, pyrrolidinium cations, phosphonium cations, and combinations thereof. Ionic liquids having such cations have been found to promote the formation of particularly stable solid electrolyte interfaces (SEIs) on the surface of the battery anode. While not limited to theory, this can favorably assist the cyclability of the cell by reducing the tendency to form dendrites and improving the safety characteristics of the device.

[0092] Examples of cations suitable for free ionic liquids include N,N-dialkylpyrrolidinium cations, such as N-methyl-N-propylpyrrolidinium (C3mpyr) and N-butyl-N-methylpyrrolidinium (C4mpyr), alkylpyridinium cations, such as 3-methyl-1-propylpyridinium, and ammonium cations, such as N-ethyl-tris(2-(2-methoxyethoxy)ethyl)ammonium (N 2(2o2o1)3 ), and tetraalkylphosphonium cations, such as trihexyl(tetradecyl)phosphonium(P 66614 ), diethyl(methyl)(isobutyl)phosphonium(P 122i4 ), triisobutyl(methyl)phosphonium(P 1i4i4i4 ), triethyl(methyl)phosphonium(P 1222 ), trimethyl(isobutyl)phosphonium(P 111i4 ) are some examples.

[0093] Free ionic liquids may contain a wide range of anions to balance the charge of selected cations, provided that they are sufficiently electrochemically stable within the cell (e.g., against redox reactions). In some embodiments, the free ionic liquid is alkyl phosphate, biscarbonate, sulfonylimide, e.g., bis(trifluoromethanesulfonyl)imide (TFSI; bistrifluimide; N(SO2CF3)2 -), bis(fluorosulfonyl)imide (FSI;N(SO2F)2 - ); Fluorosulfonyl-trifluoromethanesulfonyliimide (FTFSI); N(SO2C2F5)2 - , N(SO2CF3)(SO2C4F9) - , N(SO2CF3)(SO2Ar) - (In the formula, Ar is an aryl group), N(SO2CF3)(SO2R) - (wherein R is an alkyl group), N(SO2CF3)(COCF3) - Examples include sulfonylmethides, such as tris(trifluoromethanesulfonyl)methide and fluorinated alkyl sulfonates (RSO3 - (wherein R is a partially fluorinated alkyl, which may be a perfluoroalkyl)), fluorinated alkyl carboxylate (RCO2 - (wherein R is a partially fluorinated alkyl, which may be a perfluoroalkyl)), hexasubstituted phosphate (PF6 - PF3(CF3)3 - , PF3(C2F5)3 - (including), tetrasubstituted borates (e.g., BF4) - , B(CN)4 - In some cases, fluorinated C 1-4 Alkyl-BF3 - (BF3(CH3) - BF3 (CF3) - BF3 (C2H5) - BF3 (C2F5) - BF3 (C3F7) - (including), triflate (OTf, OSO2CF3) - The free ionic liquid includes an anion selected from a first group of counter anions consisting of ), and combinations thereof. In some preferred embodiments, the free ionic liquid includes an anion selected from bis(trifluoromethanesulfonyl)imide (TFSI), triflate (OTf), tetrafluoroborate (BF4), hexafluorophosphate (PF6), bis(fluorosulfonyl)imide (FSI), fluorosulfonyl-(trifluoromethanesulfonyl)imide (FTFSI), and combinations thereof.

[0094] In other embodiments, the organic liquid electrolyte comprises or consists of a polar aprotic molecular compound, particularly a polar aprotic solvent (i.e., a liquid at room temperature). Examples of suitable polar aprotic molecular compounds include linear ethers, cyclic ethers, esters, carbonates, lactones, nitriles, amides, sulfones, sulfolanes, diethyl ethers, dimethoxyethane, tetrahydrofuran, dioxane, dioxolane, methyltetrahydrofuran, methyl formate, ethyl formate, methyl propionate, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dibutyl carbonate, butyrolactone, acetonitrile, benzonitrile, nitromethane, nitrobenzene, dimethylformamide, N-methylpyrrolidone, dimethyl sulfone, tetramethylene sulfone, sulfolane, thiophene, and combinations thereof.

[0095] Solid polymer anode liquid layer The rechargeable lithium metal cell disclosed herein includes a solid polymer anode liquid layer adjacent to the anode as one of the lithium conductive layers interposed between the anode and the cathode. The solid polymer anode liquid layer (which may be referred to as the "first solid polymer anode liquid layer" in embodiments where a "second solid polymer anode liquid layer" is present) includes (i) a block copolymer comprising at least one hydrophobic nonionic block and at least one ionic block; (ii) a lithium salt; and optionally (iii) a liquid organic electrolyte. Despite the presence of the lithium salt and any liquid organic electrolyte, the solid polymer anode liquid layer exhibits at least two glass transition temperature (Tg) values.

[0096] "Block copolymer" means a polymer chain comprising (i) polymerization monomer residues that provide a hydrophobic nonionic block, and (ii) polymerization monomer residues that provide an ionic block. For example, a block copolymer may be an AB diblock linear copolymer, where A represents a hydrophobic nonionic block and B represents an ionic block. A block copolymer may contain three or more blocks. For example, a block copolymer may be a triblock copolymer in the form of ABA, where each A is a hydrophobic nonionic block and B is an ionic block. A suitable block copolymer also includes a graft copolymer, for example, an ionic polymer having a pendant hydrophobic polymer chain grafted thereon, provided that the copolymer remains capable of phase separation into hydrophobic and hydrophilic domains according to the principles disclosed herein.

[0097] Block copolymers may comprise a carbon chain skeleton (…-CCCCCC-…) of the kind obtained by polymerizing ethylenically unsaturated monomers (i.e., monomers whose polymerizable functional groups contain carbon-carbon double bonds). Thus, each block of a block copolymer may comprise a linear carbon chain segment of a block copolymer skeleton formed by polymerizing one or more ethylenically unsaturated monomers suitable for forming the required ionic or nonionic block.

[0098] The block copolymer present in the liquid layer of the solid polymer anode contains at least one hydrophobic nonionic block. The term "nonionic block" refers to a polymer block that does not contain an ionic charge. In other words, a hydrophobic nonionic block is a neutral polymer block.

[0099] The nonionic block contains polymerization residues of hydrophobic monomers. “Hydrophobic monomer” means a monomer that, when homopolymerized or copolymerized with one another, forms a polymer that is substantially insoluble in water. In the context of the present invention, the hydrophobic monomer is such that the resulting nonionic block is sufficiently nonpolar to phase-separate from the polar ionic block, thereby providing distinct polymer domains corresponding to different Tg values ​​in the solid polymer anode liquid layer.

[0100] There are no restrictions on the types of hydrophobic monomer residues that can be used for the purposes of the present invention, as long as the desired hydrophobic properties are induced. For example, the hydrophobic monomer residues may be derived from ethylenically unsaturated monomers such as (meth)acrylate monomers, vinyl ester monomers, styrene monomers, or combinations thereof. As used herein, the term (meth)acrylate includes both acrylate and methacrylate.

[0101] In some embodiments, the hydrophobic monomer residues are derived from styrene or styrene derivatives, indene or indene derivatives, vinylpyridine or vinylpyridine derivatives, alkyl (meth)acrylate or (meth)acrylate derivatives, vinylnaphthalene or derivatives, or combinations thereof. For example, the hydrophobic monomer residues may be derived from styrene, α-methylstyrene, methylstyrene, chlorostyrene, hydroxystyrene, vinylbenzyl chloride, methylindene, ethylindene, trimethylindene, vinylmethylpyridine, vinylbutylpyridine, vinylquinoline, vinylacridine, methyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, vinylcarbazole, or combinations thereof. In some preferred embodiments, the hydrophobic monomer residues are derived from styrene or methyl methacrylate, preferably styrene.

[0102] In some embodiments, the hydrophobic nonionic block has the following structures (I) and (II): [ka] (In the formula, R 1 , R 2 , R 3 and R 4a These are, independently, H or C 1-6 It is alkyl, R 4 C 1-12 It comprises a repeating unit having at least one alkyl, cycloalkyl, or bicycloalkyl group. In some embodiments, the repeating unit has structure (I), where R 1 and R 2 Both are H, and R 3 is H or methyl, and R 4 is C 1-12 It is alkyl, cycloalkyl, or bicycloalkyl. In some embodiments, the repeating unit has structure (II), where R 1 , R 2 , R 3 and R 4a Each of these is H.

[0103] The block copolymer present in the liquid layer of the solid polymer anode also contains at least one ionic block. The term "ionic block" refers to a polymer block containing an overall ionic charge that is balanced by counterions that are not covalently bonded to the polymer.

[0104] The ionic block may include (a) a pendant organic ionic liquid cation having a counter anion, (b) a pendant anionic moiety having a counter cation, or (c) a polymerized monomer residue covalently bonded to a combination thereof.

[0105] The polymerization monomer residues of the ionic block may be derived from ionic monomers having polymerizable ethylenically unsaturated groups such as (meth)acryloyl, (meth)acryloyloxy, vinyl ester, or styryl group. The polymerization monomer residues of the ionic block may be derived from functionalized styrene, functionalized indene, functionalized vinylpyridine, functionalized (meth)acrylate, functionalized (meth)acrylamide, or a combination thereof. In any case, the starting monomer is functionalized with a functional group that can be converted after polymerization to introduce a pendant organoionic liquid cation or pendant anionic moiety.

[0106] In some embodiments, the ionic block comprises a polymerized monomer residue to which a pendant organic ionic liquid cation is covalently bonded. The type of pendant organic ionic liquid cation is not particularly limited, as long as it exists as a pendant portion on the monomer residue forming the backbone of the ionic block. The pendant organic ionic liquid cation may include any known ionic liquid cation type, particularly organic nitrogen and organic phosphate ionic liquid cations. Preferred examples include imidazolium, pyrrolidinium, phosphonium, pyridinium, ammonium, benzimidazolium, pyrrolium, indium, carbazolium, quinolinium, piperidinium, piperadinium, and sulfonium cations. In some embodiments, the pendant organic ionic liquid cation is selected from imidazolium, pyrrolidinium, phosphonium, pyridinium, and ammonium. The cation may be monosubstituted, disubstituted, or trisubstituted, typically alkyl-substituted, and each alkyl independently is C 1-8 It is defined as containing a linear, branched, or cyclic carbon moiety.

[0107] In some embodiments, the pendant ionic liquid cation is selected from 1-alkylene-3-alkyl-imidazolium cations, N-alkylene-N-alkyl-pyrrolidinium cations, and alkylene-trialkyl-phosphonium cations, and in each case, the cation is covalently bonded to the polymerization monomer residue via an alkylene (i.e., alkanediyl) moiety. In each case, the alkylene may optionally be a C1-C 12 alkylene group, such as a C1-C6 alkylene group, for example, an ethylene (-CH2CH2-) group. In each case, the alkyl group(s) may be (independently) C1-C 16 alkyl groups, such as C1-C6 alkyl groups.

[0108] In some embodiments, the pendant organic ionic liquid cation is a dialkylimidazolium cation (1,3-dialkylimidazolium cation) covalently bonded to the polymerization monomer residue of the ionic block via one alkyl group (i.e., the alkyl group acting as a linker, which is appropriately called an alkylene group) of the imidazolium cation.

[0109] Each pendant organic ionic liquid cation in the ionic block is covalently bonded to the carbon chain backbone of the ionic block by a linking functional group, and its nature depends on the polymerizable ethylenic unsaturated group of the original monomer. For example, the linking group may be a carboxylate ester (-C[=O]O-; derived from a (meth)acrylate monomer), an amide (-C[=O]NR'-, where R' is C1-6 alkyl or H; derived from an acrylamide monomer) or a benzene-diyl (derived from a styrene monomer).

[0110] In some embodiments, the ionic block has the following structure (III):

Chemical formula

[0111] The pendant organic ionic liquid cation has a counteranion. A wide range of counteranions are suitable, provided they neutralize the charge of the pendant organic ionic liquid cation and are sufficiently electrochemically stable within the cell (for example, against redox reactions). In some embodiments, the counteranion is a fluorinated anion.

[0112] In some embodiments, the counteranion of the pendant organic ionic liquid cation is selected from the first group of counteranions previously disclosed herein. In some preferred embodiments, the counteranion of the pendant organic ionic liquid cation is selected from bis(trifluoromethanesulfonyl)imide (TFSI), triflate (OTf), tetrafluoroborate (BF4), hexafluorophosphate (PF6), bis(fluorosulfonyl)imide (FSI), fluorosulfonyl-trifluoromethanesulfonylimide (FTFSI), and combinations thereof.

[0113] In addition to, or instead of, the pendant organic ionic liquid cation, the ionic block may include polymerized monomer residues covalently bonded to the pendant anionic moiety. The properties of the pendant anionic moiety are not particularly limited, as long as they are presented as a pendant portion to the monomer residues forming the backbone of the ionic block.

[0114] In some embodiments, the pendant anionic moiety comprises a tethered sulfonylimide anion, such as a tethered bis(sulfonyl)imide anion. For example, the ionic block has the following structure (IV):

Chemical Formula

[0115] The pendant anionic moiety has a counter cation. Suitably, the counter cation can be lithium.

[0116] In one embodiment, the polymerized monomer residues of the ionic block do not covalently bond to the pendant anionic moiety.

[0117] In some embodiments, the block copolymer has the following structure (V):

Chemical Formula

[0118] In some embodiments, R 1 , R 2 , R 14 and R 15 These are H and R respectively. 3 and R 16 Each is independently H or methyl. In these or other embodiments, R 13 R may be phenyl. In these or other embodiments, R 17 This may include a dialkyl-imidazolium group covalently bonded to the polymer chain via one of its alkyl groups.

[0119] In some embodiments, the block copolymer has the following structure (Va): [ka] (In the formula, R 1 , R 2 , R 3 , R 13 , R 14 , R 15 , R 16 x and y are defined for structure (V), n has values ​​in the range of 0 to about 20, or 0 to about 10, or 0 to about 5, for example, 1 to 3, and R 8 is H or, in some cases, C is substituted. 1-6 It contains alkyl groups (for example, n-butyl).

[0120] Block copolymers can have a wide range of molecular weights, including molecular weights less than 40,000 g / mol. However, in some embodiments, the molecular weight of the block copolymer is greater than 50,000 g / mol, for example, greater than 100,000 g / mol. References to the molecular weight of polymers herein refer to those obtained by gel permeation chromatography (GPC) or 1 This is intended to mean what is determined by any of the 1H NMR spectra. In some embodiments, the molecular weight of at least one hydrophobic nonionic block of the block copolymer is greater than 18,000 g / mol, for example, greater than 25,000 g / mol. In some embodiments, at least one hydrophobic nonionic block of the block copolymer contains at least 170 monomers, for example, at least 240 monomer polymerization residues.

[0121] While we do not wish to be limited by any theory, high molecular weight block copolymers, particularly those with high molecular weight nonionic blocks, are thought to possess desirable mechanical properties that enable the production of the polymer anode liquid layer as a robust, continuous thin film adjacent to the anode. Nonionic hydrophobic block segments are preferably high molecular weight, specifically exceeding their chain-confluence molecular weight, which is known to those skilled in the art as the point at which polymer chains begin to contangle at the molecular level, resulting in a significant increase in bulk mechanical strength properties. For example, polystyrene has a chain-confluence molecular weight of about 18,000 g / mol. Therefore, when polystyrene is used as a nonionic block, such as in ABA triblock copolymers, its molecular weight is preferably greater than 18,000 g / mol, more preferably greater than 21,000 g / mol.

[0122] In some embodiments, the block copolymer is a triblock copolymer in the form of ABA, where each A is a hydrophobic nonionic block and B is an ionic block. The incompatibility between the A and B blocks results in a phase-separated form in the bulk solid state. While not wishing to be limited by any theory, it is proposed that the triblock structure may allow a single polymer molecule to span three adjacent domains in the bulk solid polymer structure, with two nonionic blocks residing in different hydrophobic domains, and a polymerized ionic liquid block in the intermediate hydrophilic domain crosslinking the two cleaved hydrophobic A domains. This crosslinking is a key feature of ABA-type thermoplastic elastomers and results in a significant improvement in bulk mechanical properties over AB-type block copolymers.

[0123] Block copolymers can be prepared by any suitable means. In some embodiments, block copolymers are prepared by a process involving the polymerization of ethylenically unsaturated monomers. Polymerization of ethylenically unsaturated monomers is preferably carried out using living polymerization techniques. Examples of living polymerization include ionic polymerization and controlled radical polymerization (CRP). Examples of CRP include, but are not limited to, inducer polymerization, stable free radical-mediated polymerization (SFRP), atom transfer radical polymerization (ATRP), and reversible addition-cleavage chain transfer (RAFT) polymerization.

[0124] In some embodiments, block copolymers are formed by polymerizing ethylenically unsaturated monomers under the control of a living polymerization agent, such as a RAFT agent. Non-limiting examples of RAFT agents suitable for use according to the present invention are commercially available and should be referred to, for example, the Sigma Aldrich catalog (www.sigmaaldrich.com) or the Boron Molecular Catalog (www.boronmolecular.com).

[0125] When living polymerization agents such as RAFT agents are used, it will be understood that block copolymers may contain the functional groups of the living polymerization agent residues, for example, at the ends of polymer chains, as terminal functional groups of structures (V) and (Va), or as linkers between adjacent hydrophobic nonionic blocks and ionic blocks.

[0126] The solid polymer anode liquid layer contains a lithium salt. The lithium cations of the lithium salt maintain charge equilibrium with anions that are not covalently bonded to the block copolymer. Therefore, the lithium salt is additive to any lithium cations that exist as counterions to the pendant anionic moieties of the ionic block. Solid electrolytes containing anionic polymers have insufficient lithium conductivity if the only lithium source present in the electrolyte is lithium that equilibrates the charge of the immobilized anionic moieties on the polymer.

[0127] Apart from this, there are no particular restrictions on the type of lithium salt that can be used, as long as the salt is chemically compatible with the other components of the composition and the anion is sufficiently electrochemically stable in the cell (e.g., against redox reactions). In some embodiments, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), lithium bis(fluorosulfonyl)imide (Li-FSI), lithium fluorosulfonyl-trifluoromethanesulfonylimide (Li-FTFSI), lithium tris(trifluoromethanesulfonyl)methide, lithium tetrakis(3,5-bis(trifluoromethyl)-2,4,6-trifluorophenyl)borate (Li[C6F3(CF3)2]4), lithium triflate (LiOTf), lithium tetrafluoroborate (LiBF4), lithium hexafluorophosphate (LiPF6), LiC n F 2n+1 SO3 - (In the formula, n is an integer from 1 to 10), LiC n F 2n+1 CO2 - (wherein n is an integer from 1 to 10), and selected from combinations thereof.

[0128] In some embodiments, the ionic block comprises a polymerization monomer residue covalently bonded to the pendant organic ionic liquid cation, where the anion of the lithium salt is the same as the counteranion for the pendant organic ionic liquid cation.

[0129] The lithium salt is present in the solid polymer anode liquid layer in an amount sufficient to facilitate good ionic conductivity, particularly lithium transport between the cathode and anode during cell cycling. In some embodiments, the solid polymer anode liquid layer contains the lithium salt in an amount of at least 10% by weight. For example, the amount of lithium salt may be about 10% to about 50% by weight, for example, about 20% to about 35% by weight, relative to the total weight of the solid polymer anode liquid layer.

[0130] In preferred embodiments, the solid polymer anode liquid layer further comprises an organic electrolyte that is not covalently bonded to the block copolymer. The organic electrolyte is typically liquid at room temperature (in the absence of other components such as the block copolymer) and can solubilize lithium salts. Thus, the organic electrolyte facilitates lithium conductivity through the solid polymer anode liquid layer and across the interface between the solid polymer anode liquid layer and the adjacent lithium conductive layer during charging and discharging of the cell. However, the amount of organic electrolyte is inevitably limited to avoid dissolution or excessive plasticization of the block copolymer, which would undesirably degrade its polymer solid structure, as is evident from the two glass transition temperature (Tg) values.

[0131] Therefore, in some embodiments, the solid polymer anode liquid layer contains an organic electrolyte in an amount of less than 50% by weight. For example, the amount of organic electrolyte may be about 1% to about 50% by weight, e.g., about 5% to about 35% by weight, or about 10% to about 30% by weight, relative to the total weight of the solid polymer anode liquid layer. Within such a range, the organic electrolyte can provide a favorable balance between the high ionic conductivity and mechanical stability of the solid polymer anode liquid layer.

[0132] In some embodiments, the organic electrolyte is selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof. In some embodiments, the organic electrolyte includes or consists of a free ionic liquid.

[0133] In some embodiments, the cations of the free ionic liquid are selected from ammonium cations, pyridinium cations, pyrrolidinium cations, phosphonium cations, and combinations thereof. Ionic liquids having such cations have been found to promote the formation of particularly stable solid electrolyte interfaces (SEIs) on the surface of the battery anode. While not limited to theory, this can favorably assist the cyclability of the cell by reducing the tendency to form dendrites and improving the safety characteristics of the device.

[0134] Examples of cations suitable for free ionic liquids include N,N-dialkylpyrrolidinium cations, such as N-methyl-N-propylpyrrolidinium (C3mpyr) and N-butyl-N-methylpyrrolidinium (C4mpyr), alkylpyridinium cations, such as 3-methyl-1-propylpyridinium, and ammonium cations, such as N-ethyl-tris(2-(2-methoxyethoxy)ethyl)ammonium (N 2(2o2o1)3 ), and tetraalkylphosphonium cations, such as trihexyl(tetradecyl)phosphonium(P 66614 ), diethyl(methyl)(isobutyl)phosphonium(P 122i4 ), triisobutyl(methyl)phosphonium(P 1i4i4i4 ), triethyl(methyl)phosphonium(P 1222 ), trimethyl(isobutyl)phosphonium(P 111i4 ) are some examples.

[0135] The free ionic liquids may contain a wide range of anions to balance the charge of the selected cation, provided that they are sufficiently electrochemically stable (e.g., against redox reactions) within the cell. In embodiments where the ionic block of the block copolymer contains a polymer monomer residue covalently bonded to a pendant organic ionic liquid cation, the anion may be the same as or different from the counteranion of the pendant organic ionic liquid cation. The anion of the free ionic liquid may also be the same as or different from the anion of the lithium salt. In some embodiments, the anion of the free ionic liquid is a fluorinated anion.

[0136] In some embodiments, the free ionic liquid comprises an anion selected from the first group of counteranions previously disclosed herein. In some preferred embodiments, the free ionic liquid comprises an anion selected from bis(trifluoromethanesulfonyl)imide (TFSI), triflate (OTf), tetrafluoroborate (BF4), hexafluorophosphate (PF6), bis(fluorosulfonyl)imide (FSI), fluorosulfonyl-(trifluoromethanesulfonyl)imide (FTFSI), and combinations thereof.

[0137] In some embodiments, the organic electrolyte comprises or consists of polar aprotic molecular compounds, particularly polar aprotic solvents (i.e., liquids at room temperature). Examples of suitable polar aprotic molecular compounds include linear ethers, cyclic ethers, esters, carbonates, lactones, nitriles, amides, sulfones, sulfolanes, diethyl ethers, dimethoxyethane, tetrahydrofuran, dioxane, dioxolane, methyltetrahydrofuran, methyl formate, ethyl formate, methyl propionate, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dibutyl carbonate, butyrolactone, acetonitrile, benzonitrile, nitromethane, nitrobenzene, dimethylformamide, N-methylpyrrolidone, dimethyl sulfone, tetramethylene sulfone, sulfolane, thiophene, and combinations thereof.

[0138] Despite the presence of lithium salts and any organic electrolytes, the solid polymer anode liquid layer remains a solid electrolyte and exhibits at least two glass transition temperature (Tg) values ​​corresponding to different solid phases of the block copolymer.

[0139] Advantageously, the solid polymer anode liquid layer is solid under the nominal operating conditions of the rechargeable lithium metal cell. For example, the solid polymer anode liquid layer may be solid at least at room temperature, e.g., about 20°C. In some embodiments, the solid polymer anode liquid layer is solid at least up to about 30°C, about 50°C, about 70°C, or about 80°C. For example, the solid polymer anode liquid layer may be solid at temperatures up to at least 100°C.

[0140] "Tg" or glass transition temperature is a temperature value that represents the temperature or temperature range at which an amorphous polymer composition (or an amorphous region in a partially crystalline polymer composition) changes from a relatively hard and brittle state to a relatively viscous or rubbery state.

[0141] In the context of the present invention, the number of Tg values ​​of a given composition is determined by differential scanning calorimetry (DSC). Those skilled in the art will know the procedure for determining the number of Tg values ​​of a sample based on DSC characterization. For example, the Tg values ​​of a composition may be defined by the stepwise increase in heat capacity as a function of temperature. The presence of Tg values ​​is determined by either the starting temperature (i.e., the beginning or ending point) or the inflection point (i.e., the midpoint). Those skilled in the art will know how to analyze such a curve and identify the number of discontinuities corresponding to the number of Tg values. For example, Tg values ​​may be determined according to ASTM E1356-08, "Standard Test Method for Assignment of the Glass Transition temperatures by Differential Scanning Calorimetry".

[0142] As used herein, the Tg of a solid polymer anode liquid layer is intended to mean that obtained by DSC analysis performed on the composition of the layer itself (i.e., including the block copolymer, lithium salts, and any organic electrolytes). Nevertheless, the measured Tg of a composition is considered to reflect the Tg of the copolymer in that composition. However, the Tg profile of a composition may differ from the Tg profile of the copolymer due to possible plasticizing effects on the copolymer from the lithium salts and / or organic electrolytes present in the composition in addition to the copolymer.

[0143] At least two Tg values ​​of the solid polymer anode liquid layer are characteristic of its morphology having microphase separation. While we do not wish to be limited by theory, such morphology is considered beneficial to both the ionic conductivity and mechanical properties of the composition. For example, a solid electrolyte morphology characterized by microphase separation is thought to ensure a preferential pathway for ion diffusion and thus promote ionic conductivity. On the other hand, such microphase separation is thought to accentuate the composite-like characteristics of the composition and thus improve its overall mechanical properties.

[0144] As used herein, the expression “microphase separation” of a composition is intended to mean the presence or formation of nanometer-sized structures resulting from the spatial self-assembly of the composition components. While not limited to theory, such self-assembling structures are thought to form periodic nanostructure morphologies having connected ion-conducting domains. When an electrolyte composition exhibits microphase separation, at least one region of the nanophase separation may be characterized by periodic nanostructure lamellae, spherical, hexagonal, 3D continuous, or discontinuous morphologies. These domains may extend one-dimensional, two-dimensional, or three-dimensionally throughout the composition. The periodicity of the nanostructure morphology, when measured by small-angle X-ray scattering (SAXS), may be characterized by ordered domains having lattice parameter dimensions in the range of about 1 nm to about 500 nm.

[0145] The Tg of the solid polymer anode liquid layer associated with the hydrophobic nonionic block of the copolymer is not limited to any specific value. For example, the Tg associated with the nonionic block may be about 40°C to about 250°C, about 40°C to about 200°C, about 40°C to about 175°C, about 40°C to about 150°C, about 40°C to about 125°C, about 40°C to about 100°C, about 50°C to about 100°C, about 60°C to about 100°C, or about 70°C to about 100°C.

[0146] Similarly, the Tg of the solid polymer anode liquid layer related to the ionic block of the copolymer is not limited to any specific value. For example, the Tg related to the ionic block may be about -100°C to about 50°C, about -100°C to about 20°C, about -100°C to about 0°C, about -100°C to about -30°C, about -100°C to about -70°C, or about -100°C to about -90°C.

[0147] The solid polymer anode liquid layer is adjacent to the anode and therefore in direct contact with the metallic lithium of the anode. Preferably, the solid polymer anode liquid layer is a continuous film covering the entire anode surface. In such a configuration, the solid polymer anode liquid layer mediates the transport of lithium ions from the anode to the cathode during discharge and from the cathode to the anode during charging. Therefore, although we do not wish to be limited by any theory, the solid polymer anode liquid layer can inhibit dendrite formation when lithium is electroplated onto the anode during charging, and can also protect the electrolyte and anode from undesirable and potentially dangerous reactions during long-term use or when the cell is physically damaged.

[0148] In some embodiments, the solid polymer anode liquid layer may have a thickness of less than 50 μm, preferably less than 20 μm, for example, 0.5 to 20 μm, or 1 to 10 μm. Surprisingly, such thin anode liquid layers have been found to be sufficient to stabilize the lithium metal anode over long-term cell cycles when used in combination with one or more additional electrolyte layers that separate the solid polymer anode liquid layer from the cathode.

[0149] The solid polymer anode liquid layer may be positioned adjacent to the anode by any means. In some embodiments, the solid polymer anode liquid layer is formed on the anode as a coating. This does not preclude the possibility of casting the solid polymer anode liquid layer onto a suitable mold or other substrate to form a film that is later transferred onto the anode surface. However, pre-formed films of preferred thickness (e.g., less than 20 μm) cannot be easily transferred onto the anode.

[0150] Second polymer anode liquid layer In some embodiments, the cell includes a second polymer anode liquid layer comprising a block copolymer, lithium salt and optionally an organic electrolyte, and having at least two glass transition temperature (Tg) values. Optionally, the second polymer anode liquid layer may have the same composition as the solid polymer anode liquid layer. The second polymer anode liquid layer is located adjacent to the first solid polymer anode liquid layer but is still separated from the cathode by one or more further electrolyte layers. Advantageously, the second solid polymer electrolyte can cover any pinholes or other defects present in the first solid polymer anode liquid layer, thus ensuring that all lithium ion transport to and from the anode passes through the solid polymer layer containing the block copolymer.

[0151] Figure 2 schematically shows a rechargeable lithium metal cell 200 according to one such embodiment. The numbered cell 200 items are generally as described herein with reference to cell 100 in Figure 1. However, cell 200 includes a second polymer anode liquid layer 212 located adjacent to the (first) solid polymer anode liquid layer 112 as one of the further electrolyte layers 114. The second polymer anode liquid layer 212 comprises a block copolymer, lithium salt and optionally an organic electrolyte as disclosed herein, and has at least two glass transition temperature (Tg) values. In fact, layer 212 may have the same composition as the solid polymer anode liquid layer 112. Layer 212 is separated from the cathode 104 by one or more further electrolyte layers 114 represented as electrolyte layer 214 in Figure 2. The electrolyte layer 214 can appropriately include one or more solid electrolyte layers, including a solid polymer cathode liquid layer, as described later.

[0152] The presence of two similar or identical block copolymer solid electrolyte layers, such as layers 112 and 212, can facilitate the manufacture of the cell. During manufacture, an anode half-cell can be manufactured that includes a solid polymer anode liquid layer bonded to the anode. For example, an anode half-cell includes an anode current collector 106, a lithium metal anode 102, and a solid polymer anode liquid layer 112. Separately, a cathode half-cell can be manufactured that includes a cathode, one or more additional electrolyte layers, and a second polymer anode liquid layer on its outer surface. For example, a cathode half-cell includes a cathode current collector 108, one or more additional electrolyte layers 114, and a second polymer anode liquid layer 212. The cell can then be manufactured by assembling the anode half-cell and the cathode half-cell and bonding the solid polymer anode liquid layer (e.g., layer 112) to the second polymer anode liquid layer (e.g., layer 212). Advantageously, the resulting cells are mechanically robust and have excellent lithium transport properties across the newly formed interface between the two half-cell components due to the bonding between the two similar or identical solid polymer electrolyte layers.

[0153] Solid cathode liquid layer In some embodiments, the rechargeable lithium metal batteries disclosed herein include a solid cathode liquid layer adjacent to the cathode as one of the additional electrolyte layers that separates the solid polymer anode liquid layer from the cathode. The solid cathode liquid layer is preferably an oxidation-resistant electrolyte layer that can withstand exposure to a highly oxidative environment adjacent to the cathode when the cell is cycled. The solid cathode liquid layer can be selected from a solid polymer cathode liquid layer and a solid inorganic electrolyte layer.

[0154] In some embodiments, the solid cathode liquid layer comprises a lithium-containing inorganic material containing mobile lithium ions, such as garnet, NASICON-type material, sulfide, or perovskite. Appropriate lithium-ion conductivity between the solid cathode liquid layer and the cathode (overcoming interfacial resistance at grain boundaries between the two layers containing particulate inorganic material) can be ensured by (i) applying high pressure to the cathode of the inorganic material containing mobile lithium ions, and / or (ii) using an organic electrolyte additive (disclosed herein) to the solid cathode liquid layer.

[0155] Solid polymer cathode liquid layer In some embodiments, the rechargeable lithium metal batteries disclosed herein include a solid polymer cathode liquid layer adjacent to the cathode as one of the further electrolyte layers that separates the solid polymer anode liquid layer from the cathode.

[0156] The solid polymer cathode liquid layer preferably contains a lithium salt, thereby providing mobile lithium ions to facilitate lithium ion transport between the anode and cathode during cell discharge and charging. The lithium cations of the lithium salt are charged in equilibrium by anions that are not covalently bonded to the polymer matrix of the solid polymer cathode liquid layer. Apart from this, there are no particular restrictions on the type of lithium salt that can be used, as long as the salt is chemically compatible with the other components of the composition and the anions are sufficiently electrochemically stable (e.g., against redox reactions) within the cell. The lithium salt may be the same as or different from the lithium salt in the solid polymer anode liquid layer. In some embodiments, it is the same salt. In some embodiments, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), lithium bis(fluorosulfonyl)imide (Li-FSI), lithium fluorosulfonyl-trifluoromethanesulfonylimide (Li-FTFSI), lithium tris(trifluoromethanesulfonyl)methide, lithium tetrakis(3,5-bis(trifluoromethyl)-2,4,6-trifluorophenyl)borate (Li[C6F3(CF3)2]4), lithium triflate (LiOTf), lithium tetrafluoroborate (LiBF4), lithium hexafluorophosphate (LiPF6), LiC n F 2n+1 SO3 - (In the formula, n is an integer from 1 to 10), LiC n F 2n+1 CO2 - (wherein n is an integer from 1 to 10), and selected from combinations thereof.

[0157] The lithium salt is present in the solid polymer cathode liquid layer in an amount sufficient to facilitate good ionic conductivity, particularly lithium transport between the cathode and anode during cell cycling. In some embodiments, the solid polymer cathode liquid layer contains at least 10% by weight of the lithium salt. For example, the amount of lithium salt may be about 10% to about 30% by weight relative to the total weight of the solid polymer anode liquid layer.

[0158] Because it is in close proximity to the high-voltage cathode material, the solid polymer cathode liquid layer preferably contains an oxidation-stabilized polymer matrix.

[0159] In some embodiments, the solid polymer cathode liquid layer comprises a fluorinated polymer, particularly a fluorinated polymer (…-CCCCCC-…) containing a carbon chain skeleton. Thus, the carbon atoms of the skeleton are at least partially fluorinated. In some embodiments, the fluorinated polymer is an ionic polymer. Preferably, the ionic fluorinated polymer contains pendant ionic groups, such as cationic groups, covalently bonded to the carbon chain skeleton. In some embodiments, the pendant ionic groups comprise one or more organic ionic liquid cations, preferably each pendant ionic group comprises multiple organic ionic liquid cations.

[0160] The organic ionic liquid cation present in the pendant ionic group may include any known ionic liquid cation type. Preferred examples include quaternary ammonium, imidazolium, benzimidazolium, pyrrolidinium, pyrrolium, indium, carbazolium, pyridinium, quinolinium, piperidinium, piperadinium, phosphonium, and sulfonium cations. The cation(s) may be monosubstituted, disubstituted, or trisubstituted, typically alkyl-substituted, and each alkyl independently may be C 1-8 It is defined as containing a linear, branched, or cyclic carbon moiety.

[0161] In some embodiments, the organoionic liquid cation(s) present in the pendant ionic group are quaternary ammonium groups, particularly tetraalkyl quaternary ammonium groups covalently bonded to the rest of the pendant ionic group via one of the alkyl groups (the alkyl group acting as a linker may appropriately be called an alkylene group).

[0162] In some embodiments, the fluorinated polymer has the following structure (VI): [ka] (In the formula, R 21 and R 22 Each of these is independently a hydrogen atom (H) or a fluorine atom (F), and R 23 The repeating unit comprises a pendant ionic group having one or more organic ionic liquid cations, preferably a pendant ionic group containing multiple organic ionic liquid cations. In some embodiments, R 21 and R 22 Both are H.

[0163] R 23 This can be a pendant ion group comprising a plurality of organic ionic liquid cations selected from quaternary ammonium, imidazolium, benzimidazolium, pyrrolidinium, pyrrolium, indium, carbazolium, pyridinium, quinolinium, piperidinium, piperarinium, phosphonium, and sulfonium cations. In some embodiments, the ionic liquid cation is a quaternary ammonium cation.

[0164] In some embodiments, the fluorinated polymer has the following structure (VII): [ka] (In the formula, R 21 , R 22 and R 23 As defined above, R 24 , R 25 and R 26 (Each element is independently either H or F, j is between 65 and 99 mol%, k is between 1 and 35 mol%, and j + k = 100 mol%) Includes. In some embodiments, j is 67-97 mol% and k is 3-33 mol%. In some embodiments, j is 70-90 mol% and k is 10-30 mol%. In some embodiments, R 21 , R 22 , R 24 , R 25 H and R 26is F. Therefore, the fluorinated polymer can be considered a PVDF-based polymer grafted with pendant ion groups. The fluorinated polymer may be a block copolymer or a random copolymer, for example, if it has structure (VII).

[0165] Pendant ionic groups, for example, R in structures (VI) and (VII). 23 The polymer may be an oligomer or polymer comprising a polymerized monomer residue to which an organic ionic liquid cation is covalently bonded. The polymerized monomer residue may be derived from an ionic monomer containing a pendant organic ionic liquid cation of the type described herein. The type of such monomer is not particularly limited, as long as they contain a polymerizable moiety and an organic ionic liquid cation. In some embodiments, the polymerizable moiety is an ethylenically unsaturated functional group, such as (meth)acryloyl, (meth)acryloyloxy, vinyl ester, or styryl group. Non-limiting classes of such monomers include (meth)acryloyloxy-ammonium, (meth)acryloyloxy-imidazolium, (meth)acryloyloxy-pyrrolidinium, and (meth)acryloyloxy-pyridinium monomers. In other embodiments, the polymerizable moiety is an epoxy functional group such as a glycidyl group.

[0166] Non-limiting examples of suitable ionic monomers include trialkylaminoalkyl(meth)acrylates (e.g., trimethylaminoethyl methacrylate or trimethylaminoethyl acrylate), trialkylaminoalkylacrylamides (e.g., trimethylaminopropylacrylamide), 1-alkyl-3-vinylimidazolium, 4-vinyl-1-alkylpyridinium, 1-(4-vinylbenzyl)-3-alkylimidazolium, 2-(methacryloyloxy)dialkylammonium, 1-(vinyloxyethyl)-3-alkylimidazolium, 1-vinylimidazolium, 1-allyliimidazolium, N-alkyl-N-allylammonium, 1-vinyl-3-alkylimidazolium, 1-glycidyl-3-alkylimidazolium, N-allyl-N-alkylpyrrolidinium, N-vinylcarbazolium, or quaternary diallyldialkylammonium cations. In these examples, each alkyl is independently C 1-10 It can be an alkyl group.

[0167] The pendant ionic group may be covalently bonded to the carbon chain skeleton of the fluorinated polymer by any suitable means. In some preferred embodiments, the pendant ionic group is produced by directly graft polymerization (a term including graft oligomerization) of an ionic monomer onto the carbon chain skeleton of the fluorinated polymer. Here, the ionic monomer includes a pendant organoionic liquid cation and a polymerizable functional group, such as an ethylenically unsaturated functional group. While the ionic monomer is preferably the only monomer present in the pendant ionic group, it is not excluded that the ionic monomer and other nonionic monomers may copolymerize to form the pendant ionic group grafted onto the carbon chain skeleton of the fluorinated polymer.

[0168] In some embodiments, graft polymerization is carried out by atom transfer radical polymerization (ATRP) using a transition metal catalyst. Suitable starting materials for graft polymerization using ATRP are (i)R 23A fluorinated polymer comprising repeating units having the structure (VI) defined above, except that is a non-fluorinated halide, or (ii)R 23 It is a fluorinated polymer containing the structure (VII) defined above, except that is a non-fluorinated halide. In all cases, R 23 The fluoride may be chloride (Cl), bromide (Br), or iodide (I), preferably Cl. The carbon-halide bond is readily activated for monomer insertion in ATRP polymerization because of the presence of a fluorine group on the polymer backbone. Transition metal catalysts for ATRP are known to those skilled in the art. For example, the catalyst may be a copper complex such as a complex of copper(I) chloride (CuCl) and 4,4'-dimethyl-2,2'-bipyridyl (bpy). Suitable reaction solvents for ATRP graft polymerization include N-methylpyrrolidone, dimethylacetamide, dimethyl sulfoxide, and acetone.

[0169] Ionic monomers can be grafted onto the carbon chain skeleton of a fluorinated polymer in an amount of 3 to 85 mol%, preferably 40 to 85 mol%, based on the total monomers in the polymer.

[0170] In some embodiments, the fluorinated polymer has the following structure (Via): [ka] (In the formula, R 21 and R 22 The structures (VI) are defined above, and R 27 is H or methyl, z refers to the number of ionic monomers present in the pendant ionic group, typically defined by the degree of graft polymerization, L 1 This is a divalent linker, for example, C 1-12 It is alkylene, R 28 It includes repeating units having an organic ionic liquid cation.

[0171] In some embodiments, the fluorinated polymer has the following structure (Vib): [Chemistry] (In the formula, R 21 , R 22 , R 27 and z are as defined for the structure (Via), and n 1 has a value in the range of 0 to about 20, or 0 to about 10, or 0 to about 5, for example 1 to 3, for example 1, and R 29 , R 30 and R 31 are each independently, optionally substituted, C 1-12 alkyl, for example C 1-6 alkyl, for example methyl).

[0172] Pendant ion groups, such as R in structures (VI) and (VII) 23 contain one or more counter anions and balance the charge of one or more organic ionic liquid cations. A wide range of counter anions are suitable if they neutralize the charge of the organic ionic liquid cation and are sufficiently electrochemically stable in the cell (e.g., for redox reactions). Preferably, the counter anion is a fluorinated counter anion.

[0173] In some embodiments, the counter anion of the pendant ion group is selected from the first group of counter anions disclosed hereinabove. In some preferred embodiments, the counter anion(s) of the pendant ion group are selected from bis(trifluoromethanesulfonyl)imide (TFSI), triflate (Otf), tetrafluoroborate (BF4), hexafluorophosphate (PF6), bis(fluorosulfonyl)imide (FSI), fluorosulfonyl-(trifluoromethanesulfonyl)imide (FTFSI), and combinations thereof.

[0174] The counter anion of the pendant ion group may be the same as or different from the anion of the lithium salt present in the solid polymer cathode liquid layer. The counter anion may also be the same as or different from any of the anions present in the solid polymer anode liquid layer (e.g., from any counter anion for a lithium salt, any free ionic liquid electrolyte, and / or an ionic block).

[0175] The molecular weight of the fluorinated polymer can range from 30,000 to 2,000,000 g / mol, such as 100,000 to 1,500,000 g / mol. The average molecular weight can be calculated based on the intrinsic viscosity [η] in the estimation formula.

[0176] In some embodiments, the solid polymer cathode liquid layer contains an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof, as disclosed earlier herein.

[0177] In some embodiments, the solid polymer cathode liquid layer contains a free ionic liquid. In some embodiments, the cation of the free ionic liquid is selected from ammonium cations, pyridinium cations, pyrrolidinium cations, phosphonium cations, and combinations thereof. In some embodiments, the anion of the free ionic liquid is a fluorinated anion. Non-limiting examples of suitable free ionic liquids include 3-methyl-1-propylpyridinium bis(fluorosulfonyl)imide, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, and equivalent bis(trifluoromethanesulfonyl)imide salts.

[0178] In some embodiments, the solid polymer cathode liquid layer contains a lithium salt in combination with a polymer capable of solubilizing the lithium salt. Preferably, the polymer is a poly(alkylene oxide), such as polyethylene oxide. In some embodiments, the polymer exists as a second polymer in combination with a fluorinated polymer. The fluorinated polymer may be ionic or nonionic, such as a nonionic fluorinated polymer, like polyvinylidene fluoride cohexafluoropropylene. Non-limiting examples of compositions for such solid polymer cathode liquid layers comprising the first and second polymers are disclosed in U.S. Patent Application Publication No. 2009 / 0162754.

[0179] In some embodiments, the solid polymer cathode liquid layer comprises (i) a monomer containing an ionic liquid cation and (ii) another ionic additive selected from the polymer or copolymer thereof. Here, the monomer containing an ionic liquid cation may be of the type described herein with respect to ionic monomers used in graft polymerization reactions.

[0180] Despite the presence of lithium salts, any free ionic liquids or other liquid organic electrolytes, any second polymer, and any other additives, the solid polymer cathode liquid layer remains a solid electrolyte. Therefore, it can be solid at least at room temperature, for example, about 20°C. In some embodiments, the solid polymer cathode liquid layer is solid at least up to about 30°C, about 50°C, about 70°C, or about 80°C. For example, the solid polymer cathode liquid layer can be solid at temperatures up to at least 100°C.

[0181] The solid polymer cathode liquid layer is adjacent to the cathode and may therefore be in direct contact with the high-voltage cathode material of the cathode. Advantageously, the solid polymer cathode liquid layer disclosed herein has been found to be highly stable against oxidation by the high-voltage cathode material while providing excellent lithium conductivity from anode to cathode during discharge and from cathode to anode during charging.

[0182] The solid polymer cathode liquid layer is preferably a continuous film covering the entire cathode surface. However, it should be understood that the solid polymer cathode liquid layer and the cathode do not need to be completely separate layers intersecting at a planar interface. In some embodiments, the polymer-based composition of the solid polymer cathode liquid layer is incorporated into the porosity of the cathode. Integration of the solid polymer cathode liquid layer and the cathode can advantageously facilitate lithium ion transport to and from the high-voltage cathode material throughout the entire cathode structure. Nevertheless, the solid polymer cathode liquid layer forms a spacer layer between the cathode, particularly between the particulate high-voltage cathode material within the cathode and the solid polymer anode liquid layer.

[0183] The solid polymer cathode liquid layer may have a thickness of less than 50 μm, preferably less than 20 μm, above the cathode surface, for example, between 0.5 and 20 μm, or between 1 and 10 μm. Therefore, the solid polymer anode liquid layer is spaced at least by the thickness of this layer from the cathode. Surprisingly, it has been found that such a thin cathode liquid layer is sufficient to make the high-voltage cathode compatible with the other electrolyte layers of the cell containing the solid polymer anode liquid layer.

[0184] The solid polymer cathode liquid layer may be positioned adjacent to the cathode by any means. For example, the solid polymer cathode liquid layer can be cast onto a suitable mold or other substrate to form a film that will later be transferred onto the cathode surface. However, in some embodiments, the cathode liquid composition is applied to the cathode as a precursor fluid so as to penetrate the porous structure of the cathode. In this case, a sufficient amount of the cathode liquid composition is applied so as to penetrate the porous cathode and form a continuous upper layer film on the surface of the cathode. The subsequent drying and / or curing of the cathode liquid composition forms a solid polymer cathode liquid layer on the cathode.

[0185] intermediate electrolyte layer In some embodiments, the cell includes an intermediate electrolyte layer interposed between a solid cathode liquid layer (e.g., a solid polymer cathode liquid layer as disclosed herein) and a solid polymer anode liquid layer. The intermediate electrolyte layer can be selected from a solid polymer electrolyte layer, a solid inorganic electrolyte layer, and a liquid electrolyte layer. The intermediate electrolyte layer can facilitate lithium ion conduction between the solid cathode liquid layer and the solid polymer anode liquid layer (and thus between the cathode and the anode) during use. Without being limited to any theory, the intermediate electrolyte layer (i) helps to make these layers compatible by reducing the interfacial resistance that would exist if the solid cathode liquid layer and the solid polymer anode liquid layer were directly adjacent, thus reducing the internal resistance of the cell; (ii) provides a reservoir of lithium salts for replenishing lithium salts present in the solid cathode liquid layer and the solid polymer anode liquid layer (in preferred embodiments, this is a very thin layer, for example, less than 20 μm); and / or (iii) provides a minimum separation distance between the solid polymer anode liquid layer and the cathode.

[0186] In some embodiments, the intermediate electrolyte layer is a solid polymer electrolyte layer. The intermediate solid polymer electrolyte layer may include a conductive polymer composition comprising a fluorinated polymer, preferably a fluorinated polymer containing pendant ion groups covalently bonded to a carbon chain skeleton as disclosed herein, together with a lithium salt and optionally a free ionic liquid or other liquid organic electrolyte additive as disclosed herein.

[0187] In some embodiments, the intermediate solid polymer electrolyte layer includes a porous separator impregnated with a conductive polymer composition. The porous separator may be a microporous polymer film. For example, the porous separator may include polyolefins (polyethylene, polypropylene, etc.), fluororesins (polytetrafluoroethylene, etc.), polyaramid, or polyimide. Alternatively, the porous separator may include paper or nonwoven fabric containing resin fibers or glass fibers. The separator may include a single film, multiple films, for example, a laminated structure of polyethylene film / polypropylene film / polyethylene film. The porous separator can be impregnated with a conductive coating to facilitate impregnation by the conductive polymer composition and ion conduction through the electrolyte layer. Examples of such impregnated separators and methods for producing them are disclosed in U.S. Patent Application Publication No. 2019 / 0270876 and Japanese Patent No. 7138267.

[0188] Figure 3 schematically shows rechargeable lithium metal cells 300 according to several embodiments. The numbered cell 300 items are generally as described herein with reference to cell 100 in Figure 1. Each lithium conductive layer 110 of cell 300 is a solid electrolyte layer. Cell 300 includes a solid polymer cathode liquid layer 314 as one of a further electrolyte layer 114 that separates the polymer anode liquid layer 112 from the cathode 104. The cathode liquid layer 314 includes (i) a fluorinated polymer containing pendant ionic groups covalently bonded to a polymer backbone as disclosed herein, (ii) a lithium salt, and optionally (iii) a free ionic liquid. The composition of the cathode liquid layer 314 may penetrate the porosity of the cathode 104, but nevertheless, the cathode liquid layer 314 forms a continuous top film on the surface of the cathode 104 having a thickness of 1 to 10 μm, for example, about 5 μm (denoted as d2).

[0189] Cell 300 includes an intermediate electrolyte layer 316 interposed between a solid polymer cathode liquid layer 314 and a solid polymer anode liquid layer 112, as another further electrolyte layer 114. The intermediate electrolyte layer 316 includes a porous separator impregnated with a conductive polymer composition comprising (i) a fluorinated polymer containing pendant ion groups covalently bonded to a polymer backbone as disclosed herein, (ii) a lithium salt, and optionally (iii) a free ionic liquid.

[0190] Cell 300 also optionally includes a second polymer anode liquid layer 312, which is located adjacent to the solid polymer anode liquid layer 112 but separated from the cathode 104 by layers 314 and 316, as another further electrolyte layer 114. The second polymer anode liquid layer 312 may have the same composition as the solid polymer anode liquid layer 112. As described for cell 200, the presence of two similar or identical solid polymer electrolyte layers, such as layers 112 and 312, can facilitate the manufacture of the cell and reduce the risk to cell performance caused by pinholes or other defects present in the solid polymer anode liquid layer 112.

[0191] While intermediate solid polymer electrolyte layers containing ionic fluorinated polymers have been successfully demonstrated herein, other lithium-conductive polymer compositions are also conceivable. In some embodiments, for example, the intermediate solid polymer electrolyte layer comprises a lithium-solubilized nonionic polymer, such as a poly(alkylene oxide) including polyethylene oxide, in combination with a lithium salt and optionally a free ionic liquid. Non-limiting examples of such polymer electrolyte compositions and their ability to reduce interlayer interfacial resistance in lithium cells are disclosed in European Patent No. 3285324.

[0192] liquid electrolyte layer In some embodiments, the cell includes a porous separator permeated with a liquid electrolyte containing a lithium salt, as a further electrolyte layer separating the solid polymer anode liquid layer from the cathode. Optionally, this liquid electrolyte layer is an intermediate electrolyte layer interposed between the solid polymer cathode liquid layer and the solid polymer anode liquid layer, as disclosed herein.

[0193] The porous separator may be according to any of the embodiments disclosed herein in relation to a further solid polymer electrolyte layer. For example, the porous separator may be a microporous polymer film impregnated with a conductive coating to facilitate penetration by the liquid electrolyte.

[0194] The liquid electrolyte contains a lithium salt dissolved in a liquid carrier of the electrolyte. The lithium salt may be the same as or different from the lithium salt in the liquid layer of the solid polymer anode. In some embodiments, it is the same salt. In some embodiments, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), lithium bis(fluorosulfonyl)imide (Li-FSI), lithium fluorosulfonyl-trifluoromethanesulfonylimide (Li-FTFSI), lithium tris(trifluoromethanesulfonyl)methide, lithium tetrakis(3,5-bis(trifluoromethyl)-2,4,6-trifluorophenyl)borate (Li[C6F3(CF3)2]4), lithium triflate (LiOTf), lithium tetrafluoroborate (LiBF4), lithium hexafluorophosphate (LiPF6), LiC n F 2n+1 SO3 - (In the formula, n is an integer from 1 to 10), LiC n F 2n+1 CO2 - (wherein n is an integer from 1 to 10), and selected from combinations thereof.

[0195] In some embodiments, the liquid electrolyte includes a free ionic liquid. The free ionic liquid may be present as the main or sole liquid component of the liquid carrier. Optionally, the free ionic liquid may be supplemented by a tetraglyme (C + H 10 O5), a polar aprotic molecular liquid such as vinylidene carbonate (VC), fluoroethylene carbonate (FEC), and / or other electrolyte additives known to those skilled in the art. 22

[0196] In some embodiments, the cation of the free ionic liquid is selected from ammonium cations, pyridinium cations, pyrrolidinium cations, phosphonium cations, and combinations thereof. In some embodiments, the anion of the free ionic liquid is a fluorinated anion. The anion may be selected from the first group of counter anions as disclosed hereinabove. Non-limiting examples of suitable free ionic liquids include 3-methyl-1-propylpyridinium bis(fluorosulfonyl)imide, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, and equivalent bis(trifluoromethanesulfonyl)imide salts.

[0197] The ionic liquid-based liquid electrolyte is preferred for its good compatibility with lithium metal anodes and high-voltage cathodes, but it is not excluded that the liquid electrolyte includes an organic solvent as a carrier for lithium salts. Thus, the liquid electrolyte may include a carbonate solvent. For example, the carbonate solvent may include one or more of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, and propylene carbonate.

[0198] ​Figure 4 schematically shows rechargeable lithium metal cells 400 according to several embodiments. The numbered cell 400 items are generally as described herein with reference to cell 100 with reference to Figure 1. Cell 400 includes a solid polymer cathode liquid layer 414 as one of a further electrolyte layer 114 that separates the polymer anode liquid layer 112 from the cathode 104. The cathode liquid layer 414 includes (i) a fluorinated polymer containing pendant ionic groups covalently bonded to the polymer backbone disclosed herein, (ii) a lithium salt, and optionally (iii) a free ionic liquid. The composition of the cathode liquid layer 414 may penetrate the porosity of the cathode 104, but nevertheless, the cathode liquid layer 414 forms a continuous top layer on the surface of the cathode 104 having a thickness of 1 to 10 μm, for example, about 5 μm (denoted as d2).

[0199] Cell 400 includes an intermediate liquid electrolyte layer 416 interposed between the solid polymer cathode liquid layer 414 and the solid polymer anode liquid layer 112, as another further electrolyte layer 114. The liquid electrolyte layer 416 includes a porous separator permeated with a liquid electrolyte containing a free ionic liquid and a lithium salt.

[0200] The liquid electrolyte layer can be manufactured within the cell structure by any method. In some embodiments, a porous separator is placed in contact with the solid polymer cathode liquid layer in the absence of the liquid electrolyte, and then the liquid electrolyte is permeated into it. For example, the porous separator may be sandwiched between the solid polymer cathode liquid layer and the solid polymer anode liquid layer in the cell structure, as shown in Figure 4, and then the liquid electrolyte composition is permeated into the porosity of the separator under vacuum.

[0201] solid inorganic electrolyte layer In some embodiments, the cell includes a solid inorganic electrolyte layer containing mobile lithium ions as a further electrolyte layer separating the solid polymer anode liquid layer from the cathode. Optionally, this solid inorganic electrolyte layer is an intermediate electrolyte layer interposed between the solid polymer cathode liquid layer and the solid polymer anode liquid layer, as disclosed herein. However, the solid inorganic electrolyte layer may also be miscible with the cathode by other means, including locating it directly adjacent to the cathode and applying very high pressure compression to reduce resistance at the interface between the two solid layers. Accordingly, some embodiments of the present invention do not include the solid polymer cathode liquid layer disclosed herein.

[0202] The solid inorganic electrolyte layer may contain a lithium-containing inorganic material selected from garnet, NASICON-type material, sulfide, and perovskite. A non-limiting example of a suitable garnet is Li 6.25 La3Zr2Al 0.25 O 12 Li 6.6 La3Zr 1.6 Ta 0.4 O 12 Li 6.75 La3Zr 1.75 Nb 0.25 O 12 (Cubic phase) and Li7La3Zr2O 12 LLZ materials such as (tetra), and Li 0.33 La 0.55 TiO3 (cubic phase), Li 0.33 La 0.55 TiO3 (tetragonal phase), Li5La3Ta2O 12 and Li6La3Ta 1.5 Y 0.5 O 12 Examples of LLZ materials include L i(1+X) Al X Ti (2-X) (PO4)3 (wherein x = 0.1 to 1.5, preferably 0.1 to 0.8), for example Li 1.4 Al 0.4 Ti 1.6 (PO4)3, Li (1+4x)Zr (2-x) (PO4)3 (x = 0.1 to 1.5, preferably 0.1 to 0.8, and part of Zr may be substituted with an element selected from the group consisting of Al, Ca, Ba, Sr, Sc, Y and In), LATP materials, e.g., Li3PO4, Li4SiPO4, Li4SiPO4-Li3PO4, Li3BO4, and LAGP materials, e.g., Li 1.5 Al 0.5 Ge 1.5 P3O 12 Examples include Li2S,P2S5, and Li. 3.25 P 0.95 S4, Li 3.2 P 0.96 S4, Li4P2S6, and Li7P3S 11 and Argyrodite Li6PS5Cl-B r Examples include La x Li y TiO z Particularly preferred materials are lithium lanthanum zirconate garnet, i.e., LLZO-Nb (garnet), lithium aluminum titanium phosphate, i.e., LATP (NASICON), and argyrodite Li6PS5Cl-Br (sulfide).

[0203] The solid inorganic electrolyte layer may further comprise one or more of the following components: (i) a fluorinated ionic polymer, for example, a fluorinated polymer containing pendant ionic groups covalently bonded to a polymer backbone as disclosed herein; (ii) a nonionic polymer, for example, a polyalkylene glycol derivative; (iii) an ionic additive selected from free ionic liquids, a monomer containing an ionic liquid cation and its polymer; and (iv) a lithium salt. Non-limiting examples of inorganic electrolyte compositions suitable for the solid inorganic electrolyte layer are disclosed in U.S. Patent Application Publication No. 2020 / 0350616.

[0204] Figure 5 schematically shows rechargeable lithium metal cells 500 according to several embodiments. The numbered cell 500 items are generally as described herein with reference to cell 100 in Figure 1. Each lithium conductive layer 110 of cell 500 is a solid electrolyte layer. Cell 500 includes a solid polymer cathode liquid layer 514 as one of a further electrolyte layer 114 that separates the polymer anode liquid layer 112 from the cathode 104. The cathode liquid layer 514 includes (i) a fluorinated polymer containing pendant ionic groups covalently bonded to a polymer backbone as disclosed herein, (ii) a lithium salt, and optionally (iii) a free ionic liquid. The composition of the cathode liquid layer 514 may penetrate the porosity of the cathode 104, but nevertheless, the cathode liquid layer 514 forms a continuous top layer on the surface of the cathode 104 having a thickness of 1 to 10 μm, for example, about 5 μm (denoted as d2).

[0205] Cell 500 includes an intermediate solid inorganic electrolyte layer 516 interposed between the solid polymer cathode liquid layer 514 and the solid polymer anode liquid layer 112 as another further electrolyte layer 114. The solid inorganic electrolyte layer 516 contains a lithium-containing inorganic material together with one or more of the following: a fluorinated ionic polymer, a nonionic polymer, an ionic additive, and a lithium salt.

[0206] Cell 500 also optionally includes a second polymer anode liquid layer 512, which is located adjacent to the solid polymer anode liquid layer 112 but separated from the cathode 104 by layers 514 and 516, as another further electrolyte layer 114. The second polymer anode liquid layer 512, which serves a similar purpose to layers 212 and 312 described with reference to Figures 2 and 3, may have the same composition as the solid polymer anode liquid layer 112.

[0207] How to cycle rechargeable lithium metal cells The present invention further relates to a method for cycling a rechargeable lithium metal cell disclosed herein. This method comprises one or more cycles of (i) charging the rechargeable lithium metal cell to a charge cutoff voltage of at least 4.1V, and (ii) discharging the rechargeable lithium metal cell. In some embodiments, during charging, the rechargeable lithium metal cell is charged to a charge cutoff voltage of at least 4.25V, for example, at least 4.35V, for example, at least 4.5V.

[0208] In some embodiments, the rechargeable lithium metal cell retains at least 90% of its capacity after 100 charge-discharge cycles performed at 0.2C and 50°C with a charge cutoff voltage of at least 4.25V. In some embodiments, this capacity retention is achieved with a charge cutoff voltage of at least 4.35V, or at least 4.5V.

[0209] In some embodiments, the rechargeable lithium metal cell retains at least 85% of its capacity after 100 charge-discharge cycles performed at 0.2C and 25°C with a charge cutoff voltage of at least 4.25V. In some embodiments, this capacity retention is achieved with a charge cutoff voltage of at least 4.35V, or at least 4.5V.

[0210] Manufacturing method for rechargeable lithium metal cells The present invention further relates to a method for manufacturing a rechargeable lithium metal cell disclosed herein. This method includes providing an anode half-cell including an anode and a cathode half-cell including a cathode, and assembling the anode half-cell and the cathode half-cell to provide a rechargeable lithium metal cell having a plurality of lithium conductive layers interposed between the anode and the cathode.

[0211] In some embodiments, before assembling the anode half-cell and cathode half-cell, the anode half-cell contains a solid polymer anode liquid layer bonded to the anode. Thus, this method may include a step of producing the solid polymer anode liquid layer as a coating on the anode. In some embodiments, the coating is applied by a coating technique selected from slot die coating, comma coating, or melt extrusion, which is particularly suitable for producing thin film coatings, as preferred. Subsequently, the applied coating can be dried and / or hot-pressed at high temperature and reduced pressure to produce the final structure of the solid polymer anode liquid layer bonded to the anode.

[0212] In some embodiments, the cathode half-cell includes a second polymer anode liquid layer containing a block copolymer and a lithium salt as an outer layer. The assembly of the anode half-cell and cathode half-cell then includes bonding the solid polymer anode liquid layer to the second polymer anode liquid layer, for example, under high temperature and pressure.

[0213] In some embodiments, the cathode half-cell includes a solid cathode liquid layer adjacent to the cathode, as disclosed herein. The solid cathode liquid layer may be a solid polymer cathode liquid layer containing a lithium salt. Providing a cathode half-cell may involve coating a cathode liquid composition as a precursor fluid onto a cathode substrate, so that a sufficient amount of the cathode liquid composition penetrates the porous cathode and forms a continuous upper film on the surface of the cathode. Coating may be by any suitable coating method, optionally including roller pressing and drying steps.

[0214] Here, a method for manufacturing the rechargeable lithium metal cell 200 disclosed herein will be described with reference to Figure 6, with reference to Figure 2. Thus, the numbered items in Figure 6 are generally as described herein for the cell 200.

[0215] This method includes providing an anode half-cell 610 comprising a lithium metal anode 102 present on an anode current collector 106 and a solid polymer anode liquid layer 112 bonded to the anode. For example, the solid polymer anode liquid layer 112 can be formed as a coating on the metallic lithium surface of the anode to create a layer with a thickness of 0.5 to 20 μm.

[0216] The method further includes providing a cathode half-cell 612 comprising a high-voltage cathode 104 present on a cathode current collector 108. The cathode half-cell 612 further comprises one or more additional electrolyte layers 214 and a second polymer anode liquid layer 212 as an outer layer. The electrolyte layer 214 can appropriately comprise one or more solid electrolyte layers, such as a solid polymer cathode liquid layer and / or a solid inorganic electrolyte layer, as disclosed herein. The second polymer anode liquid layer 212 comprises a block copolymer, a lithium salt and optionally a free ionic liquid, and may optionally have substantially the same composition as the solid polymer anode liquid layer 112. The second polymer anode liquid layer 212 can be formed on the electrolyte layer 214 in a manner similar to that of the solid polymer anode liquid layer 112.

[0217] The method includes the step of assembling an anode half-cell 610 and a cathode half-cell 612 (indicated by arrow 620) to provide a rechargeable lithium metal cell 200 in which multiple lithium conductive layers 110 (including layers 112, 212, and one or more layers 214) are interposed between the anode 102 and the cathode 104. This is done by stacking the two half-cells and bonding the solid polymer anode liquid layer 112 to the second polymer anode liquid layer 212. Advantageously, the resulting cell is mechanically robust and has excellent lithium transport properties across the newly formed interface 616 between the two half-cell components due to the bonding between the two similar or identical solid polymer electrolyte layers.

[0218] Cathode Half Cell The present invention further relates to a cathode half-cell suitable for manufacturing a rechargeable lithium metal cell according to some embodiments disclosed herein. The cathode half-cell comprises a cathode comprising a high-voltage cathode material and supported on a current collector; a solid polymer anode liquid layer; and one or more further electrolyte layers separating the solid polymer anode liquid layer from the cathode. The solid polymer anode liquid layer comprises (i) a block copolymer comprising at least one hydrophobic nonionic block and at least one ionic block, and (ii) a lithium salt. The solid polymer anode liquid layer has at least two glass transition temperature (Tg) values.

[0219] Cathode half-cells are intended for use in methods for manufacturing rechargeable lithium metal cells, as disclosed herein, and will be further described in the section describing such methods. [Examples]

[0220] The present invention will be described with reference to the following examples. It should be understood that these examples are illustrative of the invention described herein and are not limiting.

[0221] material A 10μm or 20μm thick battery-grade lithium metal foil, laminated on a 10μm thick copper foil, was used as the cell anode.

[0222] Two grafted PVDF polymers having the following structures (Pioxcel CB grafted PVDF and Treklite CP grafted PVDF) were obtained from Piotrek Co., Ltd (Japan). [ka]

[0223] Pioxcel CB-grafted PVDF had a molecular weight of approximately 700,000 Da and an ion content of 5-50 mol%. Treklite CP had a molecular weight of approximately 700,000 Da and an ion content of 40-85 mol%.

[0224] The polymerized ionic liquid homopolymer, poly(2-[methacryloyloxy]ethyltrimethylammonium bis(fluorosulfonyl)imide) (Treklitep-MA23F), was obtained from Piotrek Co., Ltd (Japan). The polyalkylene oxide-modified siloxane composition (TrekwetS64L) was also obtained from Piotrek Co., Ltd (Japan).

[0225] The polyalkylene triol polyacrylate (GEP-2800AA) described in Japanese Patent Publication No. 4904553, having the structure shown below, was obtained from Piotrek Co., Ltd. (Japan). [ka]

[0226] The ionic liquid 3-methyl-1-propylpyridinium bis(fluorosulfonyl)imide (MPPY-FSI) was obtained from Piotrek Co., Ltd (Japan). Lithium bis(fluorosulfonyl)imide (LiNO4F2S2; LiFSI) was obtained from a commercial supplier. Nano-sized carbon Super C65 from MTI USA was purchased to be used as conductive carbon for cathode synthesis. High nickel-content cathode material Ni 0.6 Co- 0.2 Mn 0.2 O2 (NMC622) and Ni 0.8 Co- 0.1 Mn 0.1 O2 (NMC811) was obtained from the commercial supplier Hi-Chem. Formula Li 6.5 La3Zr 1.5 Nb 0.5 O 12 The LLZO-Nb garnet material was obtained from Toshima Mnfg (Japan). Formula Li1.3 Al 0.3 Ti 1.7 P3O 12 The LATP NASICON material was obtained from Toshima Mnfg (Japan). Formula: Li6PS5Cl 0.5 Br 0.5 The (LiPSCl) algyrodite LPS-halide (Cl) sulfide material was obtained from Toshima Mnfg (Japan).

[0227] Porous polypropylene separators treated with TrekliteCP-grafted PVDF ("CP-PP separators") were obtained from Piotrek Co., Ltd. (Japan). This treatment creates a three-dimensional structured layer of ionic polymer-modified separators (2-6 μm on each side of a 15 μm polypropylene separator).

[0228] Example 1. Synthesis of block copolymer containing polymerized ionic liquid block The high molecular weight triblock polymer PS-b-PIL-b-PS was prepared using the following procedure.

[0229] RAFT agent: Synthesis of dimethyl 2,6-di((dodecylthio)thiocarbonylthio)-heptanediate [ka]

[0230] It was prepared using the same procedure as described in AMBivigou-Koumba, J.Kristen, A.Laschewsky, P.Mueller-Buschbaum, CMPapadakis. Macromol. Chem. Phys. 2009, 210, 565-578.

[0231] 1-Dodecanethiol (16.60 g, 0.082 mol) and triethylamine (8.78 g, 0.087 mol) were added to dichloromethane (100 mL) under nitrogen and cooled in an ice bath. Then, carbon disulfide (6.62 g, 0.087 mol) was added dropwise to this solution while stirring, the ice bath was removed, and the solution was allowed to return to ambient temperature while stirring, and stirring continued for a further 2 hours. A solution of dimethyl 2,6-dibromoheptanedioate (15.0 g, 0.043 mol) in dichloromethane (45 mL) was added, and stirring was continued under nitrogen at ambient temperature for a further 3 hours. The solvent was removed using a rotary evaporator, diethyl ether (approximately 150 mL) was added to the residue, and the resulting mixture was filtered through a large silica gel plug. After removing the solvent again using a rotary evaporator, the crude product was obtained as a yellow viscous oil, which was purified by column chromatography (9:1 hexane / ethyl acetate on silica gel). 1 H NMR(CDCl3)δ 4.83(t,(CO)CHS,2H),3.73(s,OCH3,6H),3.35(t,SCH2,4H),2.07-1.87(m,(CO)CHCH2,4H),1.69(quintet,SCH2CH2,4H),1.56(m,(CO)CHCH2CH2,2H),1.39(br m,SCH2CH2CH2,4H),1.35-1.20(br,CH2-dodecyl,32H),0.88(t,CH3-dodecyl,6H)ppm.

[0232] Synthesis of bis-α,ω-(dodecylthio)thiocarbonylthio-functionalized poly(2-bromoethyl acrylate), (pBrEA) [ka]

[0233] A solution of 2-bromoethyl acrylate (1500 g, 8.38 mol) and dimethyl 2,6-di((dodecylthio)thiocarbonylthio)heptanedioate RAFT agent (19.11 g, 0.0258 mmol) in ethyl acetate (3 L) was added to a 10 L capacity clear glass oil-jacketed reactor that had been pre-purged with argon. Argon was then blown into the solution via PTFE tubing for approximately 30 minutes, followed by heating to reflux temperature. The reaction solution, after stirring, was irradiated with blue light (4 × Kessil 427 nm LED light sources, operating at 50% power setting, positioned at equal intervals around the reactor and 10 cm apart from the outer wall of the reactor). 40% monomer conversion (in CDCl3) was observed. 1 The reaction was stopped when the reaction (analysis by 1H NMR) was reached. The solution was cooled and then added to petroleum ether at a steady flow rate with stirring to precipitate the product polymer. The supernatant was decanted, and the polymer residue was reprecipitated from ethyl acetate solution to hexane. The mixture was dried overnight under vacuum at ambient temperature to obtain a viscous, yellow, tar-like product. n (Calculated based on monomer conversion rate): 23750 (DP=130). GPC (dimethylacetamide / LiBr, PS std.): M n 20900, M w 23200, M w / M n 1.11, MP 22600.

[0234] Synthesis of bis-α,ω-(dodecylthio)thiocarbonylthio-functionalized polystyrene-b-poly(2-bromoethyl acrylate)-b-polystyrene, (PS-b-pBrEA-b-PS) [ka]

[0235] The polymer product from the previous step, bis-α,ω-(dodecylthio)thiocarbonylthio-functionalized poly(2-bromoethyl acrylate) (594 g, 0.025 mol), was dissolved in a mixture of styrene (3347 g, 32.1 mol) and toluene (1 L) and added to a 10 L capacity oil-jacketed reactor pre-purged with argon. Argon was then blown into the solution through a PTFE tube for approximately 30 minutes, and the reactor was then heated to an internal temperature of 117°C. 42% monomer conversion (approximately 12 hours, in CDCl3) was observed. 1 The reaction was stopped when the reaction (analysis by 1H NMR) was reached. The reaction solution was diluted with ethyl acetate to approximately twice its volume, and then poured into methanol as a steady flow while vigorously stirring mechanically. Stirring was continued overnight, and the precipitated polymer was collected by filtration, dried by suction over a filtration funnel for several hours, and further dried under vacuum in an oven at 45°C to obtain a yellow powder (approximately 1.9 kg). GPC (dimethylacetamide / LiBr, PS std.): M n 62500, M w 77450, M w / M n 1.24, Mp 75050. 1 ¹H NMR analysis revealed a PS:pBrEA molar ratio of 3.22:1, which is equivalent to a pBrEA weight fraction of 34.8%.

[0236] Synthesis of bis-α,ω-(dodecylthio)thio-carbonylthio-functionalized polystyrene-b-poly(2-(butylimidazolium (TFSI))ethyl acrylate)-b-polystyrene, (PS-b-PIL-b-PS) [ka]

[0237] Bis-α,ω-(dodecylthio)thiocarbonylthio-functionalized polystyrene-block-poly(2-bromoethyl acrylate)-block-polystyrene (1.57 kg, 34.8 wt% pBrEA fraction: 546.4 g pBrEA fraction, 3.052 mol BrEA monomer units) was dissolved in anhydrous DMF (5 L) under a dry nitrogen atmosphere while heating to 40°C. Anhydrous 1-butylimidazole (1.24 kg, 9.98 mol) was added to this solution. The temperature was raised to 80°C, and the reaction mixture was gently stirred for 24 hours to complete quaternization, forming a butylimidazolium bromide-functionalized triblock copolymer. The reaction solution was cooled to 50°C, and then a solution of lithium bis(trifluoromethanesulfonyl)imide (1.42 kg, 4.95 mol) in DMF (2.5 L) was added, stirred for 2 hours, and then cooled to ambient temperature. The mixture was further diluted by adding methyl ethyl ketone (3.6 L), and then poured into a large excess of methanol / water (1:1, 90 L) as a steady flow for 10 minutes with vigorous mechanical stirring to precipitate the product polymer. The mixture was stirred overnight, and the solid was collected by filtration and washed with deionized water (30 L). The solid was resuspended in deionized water (85 L), stirred vigorously for 24 hours, filtered, rinsed with further water, and then dried on a filter under vacuum. The solid was transferred to an oven set to 50°C and dried until constant weight was reached. Yield: 2.31 kg. 1 ¹H NMR (CDCl3 / DMSO-d6 / AcOD) δ 8.89 (br s, imidazolium NCHN), 7.60-7.40 (br m, imidazolium NCHN), 7.20-6.15 (polystyrene ArH), 4.60-3.90 (br m, OCH2CH2N, butyl-CH2N), 2.46-1.0 (skeleton CHCH2, butyl-CH2CH2), 0.84 (t, butyl-CH3) ppm. PS:PIL molar ratio 4.78:1, calculated PS weight fraction 49.7%.

[0238] The molecular weight of PS-b-PIL-b-PS was approximately 125,000 Da (31,350 Da per PS block; 63,000 PIL blocks).

[0239] The low molecular weight diblock polymer PS-b-PIL having the structure shown below was prepared by the procedure previously reported in International Publication No. 2019 / 084623. [ka]

[0240] The molecular weight of PS-b-PIL was approximately 30,000 Da (approximately 13,200 Da in the PS block), and the ion ratio was approximately 22 mol%.

[0241] The block copolymer produced in this example may be referred to below as "Pilblox" (polymerized ionic liquid block copolymer).

[0242] Example 2. Fabrication and testing of a lithium metal cell containing multiple solid polymer electrolyte layers. Referring to Figure 3, Li metal / NMC622 cells having the configuration of cell 300 described herein (with correspondingly numbered constituent layers) were prepared and evaluated.

[0243] Production

[0244] Step 1. A coating slurry for anode solution preparation was prepared by dissolving the high molecular weight triblock copolymer PS-b-PIL-b-PS (prepared in Example 1) (9 wt%) in tetrahydrofuran (THF) (81.7 wt%), followed by the addition of MPPY-FSI ionic liquid (4.2 wt%) and LiFSI lithium salt (5.1 wt%). The coating slurry was coated onto lithium metal foil (20 μm thick, laminated on copper foil) and dried under vacuum (-0.1 MPa) in an oven at 50°C for 24 hours to remove the solvent, creating a continuous Pilblox-based anode solution layer (112) with a thickness of approximately 10 μm on a lithium anode (102) supported on a copper foil current collector (106). DSC analysis of the Pilblox-based anode solution composition showed two Tg values: -59.5°C due to the ionic phase and approximately 100°C for the polystyrene phase. This completed the preparation of anode half-cells used to manufacture the cells.

[0245] Step 2. Conductive carbon (CC) and PioxcelCB-grafted PVDF were combined in a weight ratio of 1:0.6 and stirred to prepare a homogeneous powder mixture. MPPY-FSI ionic liquid was added in an amount of 0.4 to produce a conductive adhesive (grafted PVDF + ionic liquid) with a CC counter-ionic additive weight ratio of 1:1. Next, this conductive adhesive (5 wt%) was combined with NCM622 (95 wt%) in N-methyl-2-pyrrolidone (NMP) to prepare a cathode casting slurry with a non-volatile content of approximately 68 wt%. This cathode casting slurry was coated onto aluminum foil and dried under vacuum at 80°C for 1 hour to produce a 2.2 mAh / cm² current collector supported on an aluminum foil current collector (108). 2 A porous NMC622-based cathode (104) with a capacity of [amount] was manufactured.

[0246] Step 3. A first polymer electrolyte coating slurry was prepared by dissolving Treklite CP-grafted PVDF (6 wt%) in acetonitrile (70 wt%), followed by the addition of MPPY-FSI ionic liquid (18 wt%) and LiFSI lithium salt (6 wt%). This polymer electrolyte coating slurry was then roller-pressed onto a porous NMC622 cathode and dried under vacuum (-0.1 MPa) at 80°C for 24 hours, after which the slurry was injected into the porosity of the cathode, leaving a layer of liquid slurry on the surface sufficient to form a polymer cathode liquid layer (314) approximately 5 μm thick.

[0247] Step 4. A second polymer electrolyte coating slurry was prepared by dissolving Treklite CP-grafted PVDF (20% by weight) in acetonitrile (56% by weight), followed by the addition of MPPY-FSI ionic liquid (18% by weight) and LiFSI lithium salt (6% by weight). This polymer electrolyte coating slurry was coated onto the polymer cathode liquid layer (314) to create a liquid layer approximately 5 μm thick. Next, a CP-PP separator (approximately 15 μm thick) was immersed in the liquid layer, allowing the liquid to penetrate the porosity of the separator. The mixture was then dried under vacuum (-0.1 MPa) at 80°C for 24 hours to produce a further solid polymer electrolyte layer (316) on the polymer cathode liquid layer (314) containing a porous separator impregnated with the conductive polymer composition.

[0248] Step 5. Next, the coating slurry prepared in Step 1 was coated onto a further solid polymer electrolyte layer (316), and dried in a 50°C oven under vacuum (-0.1 MPa) for 24 hours to produce a second continuous Pilblox-type anode liquid layer (312) with a thickness of approximately 10 μm. This completed the preparation of the cathode half-cell used to manufacture the cell.

[0249] Step 6. Next, a lithium metal cell (300) was manufactured by stacking an anode half-cell (manufactured in Step 1) and a cathode half-cell (manufactured in Step 5) while the first and second Pilblox-based anode liquid layers (112, 312) were in contact. The cell was subjected to a vacuum (0.1 MPa) at 80°C for 10 minutes at 100 kg / cm³. 2 The Pilblox layers were bonded by heating and pressing under pressure, establishing an ionic conductive network throughout the lithium conductive layer between the cathode and anode.

[0250] Cell test

[0251] 5cm x 5cm in size and approximately 50mAh (= 5cm x 5cm x 2.2mAh / cm²) 2Cells with a theoretical capacity of ) were held in a fitting holder and evaluated at high voltage (4.3V) using the TOSCAT3600 charge / discharge test system (Toyo System Co., Ltd.) according to the test procedure shown in the table below. Initial chemical conversion processing (CCP-1) involved charging / discharging at 50°C for 10 hours to help form a uniform conductive network inside the cell structure. [Table 1]

[0252] The cycle results at 0.1C, 0.2C, and 0.5C are shown in Figure 7. At the 0.2C rating, the measured capacity was 49.76 mAh, and the Coulomb efficiency was 99.8%. The effect of 100 cycles at 0.1C and 50°C was to gradually decrease the measured capacity from 50.18 mAh to 47.48 mAh, providing a capacity retention rate of 94.6%.

[0253] Example 3. Fabrication and testing of a lithium metal cell containing an ionic liquid electrolyte layer. Referring to Figure 4, Li metal / NMC811 cells having the configuration of cell 400 described herein (with correspondingly numbered constituent layers) were prepared and evaluated.

[0254] Production

[0255] Step 1. An anode half-cell containing a Pilblox-type anode liquid layer (112) on a lithium anode (102) supported on a copper foil current collector (106) was prepared by the same procedure as in Step 1 of Example 2.

[0256] Step 2. The same procedure as in Step 2 of Example 2 was followed, except that NMC811 was used instead of NMC622, resulting in a yield of 2.2 mAh / cm². 2 A porous NMC811-type cathode (104) having a capacity and supported on an aluminum foil current collector (108) was prepared.

[0257] Step 3. A cathode half-cell was manufactured by preparing a polymer cathode liquid layer (414) on a porous NMC811-based cathode (104) using the same procedure as in Step 3 of Example 2.

[0258] Step 4. Next, a CP-PP porous polymer separator was interposed between the anode half-cell (manufactured in Step 1) and the cathode half-cell (manufactured in Step 3), the laminated structure was placed in a flat cell bag, and a lithium metal cell (400) was manufactured by injecting the liquid electrolyte into the cell under vacuum (-0.1 MPa) so that the liquid electrolyte would permeate the separator and form a liquid electrolyte layer (416). The liquid electrolyte contained vinylidene carbonate (VC) (4.6 wt%), lithium bisoxalate borate (LiBOB) (0.9 wt%), lithium LiFSI salt (1.2 M), and Trekwet S64L (1.9 wt%) dissolved in MPPY-FSI ionic liquid. The liquid electrolyte was prepared by adding 5 parts VC, 1 part LiBOB, and 2 parts Trekwet S64L to 100 parts MPPY-FSI + LiFSI 1.2 M, for a total of 108 parts. Next, the cell was heated at 50°C for 10 minutes, the flat cell bag seal was opened to allow the excess liquid electrolyte to overflow, and then it was vacuum-sealed again.

[0259] Cell test

[0260] 5cm x 5cm in size and approximately 50mAh (= 5cm x 5cm x 2.2mAh / cm²) 2 Cells with a theoretical capacity of ) were evaluated at high voltage (4.5V) using the TOSCAT3600 charge / discharge test system (Toyo System Co., Ltd.) according to the test procedures shown in the table below. The initial chemical conversion processing (CCP-1) involved charging / discharging at 50°C for 10 hours to help form a uniform conductive network inside the cell structure. [Table 2]

[0261] The cycle results at 0.1C, 0.2C, and 0.5C are shown in Figure 8. At the 0.2C rating, the measured capacity was 49.25 mAh, and the Coulomb efficiency was 99.2%. The effect of 100 cycles at 0.5C and 25°C was to provide a capacity retention rate of 93.1% by gradually decreasing the measured capacity from 46.7 mAh to 43.5 mAh.

[0262] Another Li metal / NMC811 cell with a cell 400 configuration was fabricated and evaluated. Unlike the one described above, this cell had an output of 4.0 mAh / cm². 2 The porous NMC811-based cathode (104) having a certain capacity was included, and the liquid electrolyte present in the liquid electrolyte layer (416) was 1.0 M LiPF6 in a 1:1 ethylene carbonate / diethyl carbonate solvent.

[0263] The cell was cycled at 0.5C and 25°C, yielding a measured capacity of 104mAh and a Coulomb efficiency of 99.8%. The effect of 200 cycles at 0.5C and 25°C was to provide a capacity retention rate of 94.6%, by gradually decreasing the measured capacity from 103.2mAh to 97.56mAh.

[0264] Example 4. Manufacturing and testing of a lithium metal cell containing a solid garnet-based electrolyte layer. Referring to Figure 5, Li metal / NMC811 cells having the configuration of cell 500 described herein (with correspondingly numbered constituent layers) were prepared and evaluated.

[0265] Production

[0266] Step 1. An anode half-cell containing a Pilblox-type anode liquid layer (112) on a lithium anode (102) supported on a copper foil current collector (106) was prepared by the same procedure as in Step 1 of Example 2.

[0267] Step 2. Using the same procedure as in Step 2 of Example 3, 2.2 mAh / cm² 2A porous NMC811-type cathode (104) having a capacity and supported on an aluminum foil current collector (108) was prepared.

[0268] Step 3. A cathode half-cell was manufactured by preparing a polymer cathode liquid layer (514) on a porous NMC811-based cathode (104) using the same procedure as in Step 3 of Example 3.

[0269] Step 4. An electrolyte was prepared by dissolving Treklite p-MA23F conductive additive (15% by weight) in acetone (60% by weight), followed by the addition of MPPY-FSI ionic liquid (25% by weight). Next, a garnet-based coating slurry was prepared by combining the electrolyte (13% by weight), LLZO-Nb (48% by weight), and LiFSI lithium salt (14% by weight) with acetone (25% by weight). The mixture was then mixed in a planetary centrifugal mixer (2 × 5 mins), further diluted with acetone to the optimal viscosity (achieved with a non-volatile content of 67%), and passed through a filter sieve. The garnet-based electrolyte coating slurry was coated onto a polymer cathode liquid layer (514) and dried at 40°C for 1 hour to obtain a solid inorganic (garnet-based) electrolyte layer (516) with a thickness of approximately 30 μm on the polymer cathode liquid layer (514).

[0270] Step 5. Next, the coating slurry prepared in Step 1 was coated onto the solid inorganic electrolyte layer (516), and dried in a 50°C oven under vacuum (-0.1 MPa) for 24 hours to produce a second Pilblox-based anode liquid layer (512) with a thickness of approximately 5 μm. This completed the preparation of the cathode half-cell used to manufacture the cell.

[0271] Step 6. Next, a lithium metal cell (500) was manufactured by assembling the anode half-cell (manufactured in Step 1) and the cathode half-cell (manufactured in Step 5) with the first and second Pilblox-based anode liquid layers (112, 512) in contact. The cell was subjected to a vacuum (0.1 MPa) at 80°C for 10 minutes at 100 kg / cm³. 2The Pilblox layers were bonded by heating and pressing under pressure, establishing an ionic conductive network throughout the lithium conductive layer between the cathode and anode.

[0272] Cell test

[0273] 5cm x 5cm in size and approximately 50mAh (= 5cm x 5cm x 2.2mAh / cm²) 2 Cells with a theoretical capacity of ) were evaluated at high voltage (4.3V) using the TOSCAT3600 charge / discharge test system (Toyo System Co., Ltd.) according to the test procedures shown in the table below. The initial chemical conversion processing (CCP-1) involved charging / discharging at 50°C for 10 hours to help form a uniform conductive network inside the cell structure. [Table 3]

[0274] The cycle results at 0.1C, 0.2C, and 0.5C are shown in Figure 9. At the 0.2C rating, the measured capacity was 49.64 mAh, and the Coulomb efficiency was 99.6%. The effect of 100 cycles at 0.1C and 50°C was to gradually decrease the measured capacity from 50.2 mAh to 47.7 mAh, providing a capacity retention rate of 94.9%.

[0275] Example 5. Fabrication and testing of lithium metal cells containing solid NASICON electrolyte. Referring to Figure 5, other Li metal / NMC811 cells having the configuration of cell 500 described herein (with correspondingly numbered constituent layers) were prepared and evaluated.

[0276] In the preparation step 4, the cell was prepared in the same manner as in Example 4, except that LATP was used instead of LLZO-Nb. The solid inorganic (NASICON-based) electrolyte layer (516) obtained on the polymer cathode liquid layer (514) had a thickness of approximately 30 μm.

[0277] Cell Testing: The cells were evaluated using the same test procedure as described in Example 4. The cycle results at 0.1C, 0.2C, and 0.5C are shown in Figure 10. At 0.2C, the Coulomb efficiency was 99.9%. The effect of 100 cycles at 0.1C and 50°C was to gradually decrease the measured capacity from 48.8mAh to 44.9mAh, providing a capacity retention rate of 92.8%.

[0278] Example 6. Preparation and testing of lithium metal cells containing a solid sulfide electrolyte. Referring to Figure 5, other Li metal / NMC811 cells having the configuration of cell 500 described herein (with correspondingly numbered constituent layers) were prepared and evaluated.

[0279] Except for a variation in manufacturing step 4, cells were manufactured in the same manner as in Example 4.

[0280] Step 4. The electrolyte was prepared by combining LiPSCl (50 wt%), polyalkylene triol polyacrylate (GEP-2800AA) (12 wt%), and LiFSI lithium salt (14 wt%) with THF (24 wt%). The mixture was then mixed in a planetary centrifugal mixer (2 × 5 min), further diluted with THF to the optimal viscosity (achieved with a non-volatile content of 65%), and passed through a filter sieve. A UV polymerization catalyst (OMNIRAD 651, 2,2-dimethoxy-2-phenylacetophenone-based photoinitiator) was added in an amount of 1% relative to GEP-2800AA. A sulfide-based electrolyte coating slurry was coated onto a polymer cathode liquid layer (514), polymerized under 254 nm UV irradiation for 30 minutes, and then dried at 40°C for 1 hour to obtain a solid inorganic (sulfide-based) electrolyte layer (516) with a thickness of approximately 30 μm on the polymer cathode liquid layer (514).

[0281] Cell Testing: The cells were evaluated using the same test procedure as described in Example 4, except that the cell size was only 3 cm × 3 cm (capacity approximately 12 mAh). The cycle results at 0.1C, 0.2C, and 0.5C are shown in Figure 11. At 0.2C, the Coulomb efficiency was 99.8%. The effect of 100 cycles at 0.1C, 50°C was to gradually decrease the measured capacity from 11.3 mAh to 10.5 mAh, providing a capacity retention rate of 92.9%.

[0282] Example 7 (Comparative Example): Manufacturing and testing of a solid lithium metal cell without separation of the polymer anode liquid layer from the cathode. Li metal / NMC622 cells were fabricated and evaluated as follows.

[0283] The cells were prepared in the same manner as in Example 2, except that steps 3, 4, and 5 were omitted. Therefore, referring to Figure 3, the Pilblox-type anode liquid layer (112) was in direct contact with the cathode (104) (layers 314, 316, and 312 were omitted).

[0284] Cell Testing: The cell was evaluated at a high voltage (4.3V) using the same test apparatus as described in Example 2, except that the cell size was only 3cm x 3cm (theoretical capacity approximately 13.5mAh) and the test was performed at ambient temperature (25°C). As shown in Figure 12, the device was inoperable. At 0.2C, the Coulomb efficiency was only 4.1%. The low performance is thought to be due to the high grain boundary resistance and chemical / electrochemical instability of the Pilblox-based anode liquid layer in contact with the cathode.

[0285] Example 8. Effect of Pilblox polymer structure on the formation of the polymer anode liquid layer A coating slurry for preparing the anode solution was prepared by dissolving the low molecular weight diblock copolymer PS-b-PIL (prepared in Example 1) (9 wt%) in tetrahydrofuran (THF) (81.7 wt%), followed by the addition of MPPY-FSI ionic liquid (4.2 wt%) and LiFSI lithium salt (5.1 wt%). To produce Pilblox-based anode solution layers of different thicknesses on lithium anodes, the coating slurry was coated onto lithium metal foil at different addition amounts and then dried. In contrast to the anode solution layer thickness of less than 10 μm achieved when using the high molecular weight triblock copolymer PS-b-PIL-b-PS (see, for example, Example 2), this particular formulation could only produce a continuous polymeric anode solution layer of high structural integrity with a thickness of at least 100 μm.

[0286] While we do not wish to be limited by any theory, it is proposed that PS-b-PIL-b-PS triblock copolymers offer better mechanical properties for thin film formation, particularly for high molecular weight, hydrophobic polystyrene blocks. Polystyrene undergoes conjunctivosis at higher molecular weights, specifically above approximately 18,000 Da (conjunctivosis molecular weight), resulting in a significant increase in bulk mechanical strength compared to polystyrene with molecular weights below approximately 18,000 Da. Furthermore, the triblock structure can allow a single polymer molecule to span three adjacent domains in the solid polymer microstructure, with two polystyrene blocks residing in different unconnected hydrophobic domains crosslinked by a polymeric ionic liquid block in an intermediate hydrophilic domain. This crosslinking of A-block domains, combined with conjunctivosis, is a characteristic feature of ABA-type triblock copolymer elastomers and is the main cause of the improved bulk mechanical properties of such materials. These features can lead to the formation of thin films with high structural integrity.

[0287] Li metal / NMC622 cells were prepared in the same manner as in Example 2, except that the Pilblox-based anode liquid layer produced in step 1 contained the low molecular weight diblock polymer PS-b-PIL and had a thickness of 120 μm (prepared as described above), and steps 4 and 5 were omitted. Therefore, referring to Figure 3, the thick Pilblox-based anode liquid layer (112) was in direct contact with the polymer cathode liquid layer (214) (layer 212 was omitted).

[0288] The cells were evaluated at high voltage (4.3V) using the same test apparatus as described in Example 2, except that the cell size was only 3cm x 3cm (theoretical capacity approximately 13.5mAh). The cells were cycled at 0.2C between 4.3V and 3.0V, achieving a Coulomb efficiency of 98.7%.

[0289] Example 9. Effect of free ionic liquids on lithium conductivity A coating slurry for preparing the anode solution was prepared by dissolving the low molecular weight diblock copolymer PS-b-PIL (prepared in Example 1) (20% by weight) in acetone (76% by weight), followed by the addition of a lithium LiFSI salt (4% by weight). No free ionic liquids were included in the formulation. This coating slurry was applied as a double coating to a lithium metal foil (100 μm thick) by coating a first coating with a wet thickness of 350 μm, drying at 60°C for 10 minutes, and then coating a second coating with a wet thickness of 450 μm and drying at 80°C for 30 minutes. The resulting Pilblox-based anode solution had a thickness of 125 μm.

[0290] Li metal / NMC622 cells were fabricated in the same manner as described in Example 2, except for the CR2032 coin cell format. Step 1 of the method in Example 2 was replaced with the preparation of the Pilbox-type anode liquid layer described above. In step 2, the porous NMC622-type cathode (104) was 1.5 mAh / cm². 2It had the capacity of [amount]. Since two layers of Pilblox were directly coated onto the Li anode, step 5 was omitted. Therefore, referring to Figure 3, the Pilblox-based anode liquid layer (112, 312) did not contain free ionic liquid and was in contact with the solid polymer intermediate electrolyte layer (314).

[0291] The cells were evaluated at high voltage (4.3V) and 50°C, and cycled between 4.3V and 3.0V. The solid electrolyte layer between the cathode and the Pilblox-based anode liquid layer remained protected from oxidative decomposition of the Pilblox composition. However, at cycle speeds of 0.1C, 0.2C, and 0.5C, only Coulomb efficiencies of 84.4%, 53.3%, and 2.6% were obtained, respectively. The conductivity of the cells was only 3.3 × 10⁻⁶. -8 It is S / cm.

[0292] The insufficient cycling results and low conductivity of the cell demonstrate the role of free ionic liquids in the solid electrolyte layer, promoting lithium conductivity through the electrolyte composition and / or the interface between the electrolyte layer and adjacent layers within the cell.

[0293] Those skilled in the art will understand that the invention described herein is susceptible to modifications and alterations other than those specifically described. It will be understood that the invention includes all such modifications and alterations that fall within the spirit and scope of the invention.

Claims

1. Anode containing lithium metal; Cathodes containing high-voltage cathode material; and The lithium conductive layer comprises a plurality of lithium conductive layers interposed between the anode and the cathode, wherein the lithium conductive layer comprises a solid polymer anode liquid layer adjacent to the anode and one or more further electrolyte layers that separate the polymer anode liquid layer from the cathode. A rechargeable lithium metal cell wherein the solid polymer anode liquid layer comprises (i) a block copolymer comprising at least one hydrophobic nonionic block and at least one ionic block, and (ii) a lithium salt, and the solid polymer anode liquid layer has at least two glass transition temperature (Tg) values.

2. The high-voltage cathode material has at least 4.1V vs Li / Li ＋ A rechargeable lithium metal cell according to claim 1, having an electrochemical potential.

3. A rechargeable lithium metal cell according to claim 1 or 2, which retains at least 90% of its capacity after 100 charge-discharge cycles performed at 0.2C and 50°C using a charge cutoff voltage of at least 4.25V, and / or retains at least 85% of its capacity after 100 charge-discharge cycles performed at 0.2C and 25°C using a charge cutoff voltage of at least 4.25V.

4. The rechargeable lithium metal cell according to any one of claims 1 to 3, wherein the molecular weight of the block copolymer is greater than 50,000 g / mol.

5. The rechargeable lithium metal cell according to any one of claims 1 to 4, wherein the molecular weight of at least one hydrophobic nonionic block of the block copolymer is greater than its confounding molecular weight.

6. The rechargeable lithium metal cell according to any one of claims 1 to 5, wherein the block copolymer is a triblock copolymer in the form of A-B-A, where A is a hydrophobic nonionic block and B is the ionic block.

7. The rechargeable lithium metal cell according to any one of claims 1 to 6, wherein the at least one hydrophobic nonionic block comprises a polymerization residue of a hydrophobic monomer, and the at least one ionic block comprises (a) a pendant organic ionic liquid cation having a counter anion, (b) a pendant anionic moiety having a counter cation, or (c) a polymerization monomer residue formed by covalently bonding a combination thereof.

8. The rechargeable lithium metal cell according to any one of claims 1 to 7, wherein the at least one ionic block comprises a polymerized monomer residue to which a pendant organic ionic liquid cation selected from imidazolium, pyrrolidinium, phosphonium, pyridinium, and ammonium cations is covalently bonded.

9. The rechargeable lithium metal cell according to any one of claims 1 to 8, wherein the solid polymer anode liquid layer further comprises an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof.

10. The rechargeable lithium metal cell according to any one of claims 1 to 9, wherein the solid polymer anode liquid layer has a thickness of less than 20 μm.

11. The rechargeable lithium metal cell according to any one of claims 1 to 10, wherein the solid polymer anode liquid layer is a coating on the anode.

12. The rechargeable lithium metal cell according to any one of claims 1 to 11, wherein the polymer anode liquid layer is separated from the cathode by a separation distance in the range of 15 to 45 μm.

13. The rechargeable lithium metal cell according to any one of claims 1 to 12, wherein at least one of the further electrolyte layers comprises an organic electrolyte selected from free ionic liquids, polar aprotic molecular compounds, and combinations thereof.

14. A rechargeable lithium metal cell according to any one of claims 1 to 13, wherein each of the further electrolyte layers contains a free ionic liquid.

15. The rechargeable lithium metal cell according to any one of claims 1 to 14, wherein the one or more further electrolyte layers include a solid cathode liquid layer adjacent to the cathode, and the solid cathode liquid layer is selected from a solid polymer cathode liquid layer and a solid inorganic electrolyte layer.

16. The rechargeable lithium metal cell according to claim 15, wherein the solid cathode liquid layer is a solid polymer cathode liquid layer containing a fluorinated polymer.

17. The rechargeable lithium metal cell according to claim 16, wherein the fluorinated polymer is an ionic fluorinated polymer comprising a carbon chain skeleton and a pendant ion group covalently bonded to the carbon chain skeleton.

18. The rechargeable lithium metal cell according to claim 17, wherein the pendant ionic group is produced by graft polymerization of an ionic monomer onto the carbon chain skeleton, and the ionic monomer comprises (i) a polymerizable ethylenically unsaturated functional group and (ii) an organic ionic liquid cation.

19. The rechargeable lithium metal cell according to any one of claims 15 to 18, wherein the one or more further electrolyte layers include an intermediate electrolyte layer interposed between the solid polymer anode liquid layer and the solid cathode liquid layer, and the intermediate electrolyte layer is selected from a solid polymer electrolyte layer, a solid inorganic electrolyte layer, and a liquid electrolyte layer.

20. The rechargeable lithium metal cell according to claim 19, wherein the intermediate electrolyte layer comprises a lithium conductive polymer composition comprising (i) an ionic fluorinated polymer containing a carbon chain main chain and pendant ion groups covalently bonded to the carbon chain main chain, (ii) a lithium salt, and optionally (iii) a free ionic liquid.

21. The rechargeable lithium metal cell according to claim 19 or 20, wherein the intermediate electrolyte layer comprises a porous separator permeated with a liquid electrolyte containing a lithium conductive polymer composition or a lithium salt.

22. The rechargeable lithium metal cell according to claim 19 or 20, wherein the intermediate electrolyte layer comprises a solid inorganic electrolyte layer containing mobile lithium ions, and the solid inorganic electrolyte layer comprises a lithium-containing inorganic material selected from garnet, NASICON-type material, sulfide, and perovskite.

23. The rechargeable lithium metal cell according to any one of claims 1 to 22, wherein the one or more further electrolyte layers include (i) a block copolymer comprising at least one hydrophobic nonionic block and at least one ionic block, and (ii) a second polymer anode liquid layer comprising a lithium salt, the second polymer anode liquid layer being adjacent to the solid polymer anode liquid layer and spaced apart from the cathode.

24. A rechargeable lithium metal cell according to any one of claims 1 to 23, wherein each lithium conductive layer is a solid electrolyte.

25. A method for cycling a rechargeable lithium metal cell according to any one of claims 1 to 24, comprising one or more cycles of (i) charging the rechargeable lithium metal cell to a charge cutoff voltage of at least 4.1 V, and (ii) discharging the rechargeable lithium metal cell.

26. A method for manufacturing a rechargeable lithium metal cell according to any one of claims 1 to 24, To provide an anode half-cell including the anode; To provide a cathode half-cell including the aforementioned cathode; and To provide a rechargeable lithium metal cell having the anode half-cell and the cathode half-cell assembled, with the plurality of lithium conductive layers interposed between the anode and the cathode. Methods that include...

27. The method according to claim 26, wherein, before assembling the anode half cell and the cathode half cell, the anode half cell includes the solid polymer anode liquid layer adhered to the anode.

28. The method according to claim 27, wherein providing the anode half-cell comprises generating the solid polymer anode liquid layer adhered to the anode by a coating technique selected from slot die coating, comma coating or melt extrusion.

29. The method according to any one of claims 26 to 28, wherein the cathode half cell includes a second polymer anode liquid layer containing the block copolymer and a lithium salt as an outer layer, and assembling the anode half cell and the cathode half cell includes joining the solid polymer anode liquid layer to the second polymer anode liquid layer.

30. A cathode comprising a high-voltage cathode material, wherein the cathode is supported on a current collector; Solid polymer anode liquid layer; and One or more further electrolyte layers separate the solid polymer anode liquid layer from the cathode. Includes, A cathode half-cell wherein the solid polymer anode liquid layer comprises (i) a block copolymer having at least one hydrophobic nonionic block and at least one ionic block, and (ii) a lithium salt, and the solid polymer anode liquid layer has at least two glass transition temperature (Tg) values.

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