Electrolyte system

Abstract

An electrochemical cell comprising an anode, a cathode, and an electrolyte system is provided herein, wherein the electrolyte system comprises (i) a first electrolyte comprising a solid electrolyte, and (ii) a second electrolyte comprising a liquid electrolyte, a gel electrolyte, or a combination thereof, wherein the second electrolyte has sufficient polysulfide and / or polyselenide solubility to prevent shuttling, and the second electrolyte does not come into contact with the anode. Also provided are a method for producing an electrochemical cell and an electrochemical cell assembly comprising at least one electrochemical cell.

Description

[Technical Field]

[0001] Related applications This application claims priority from UK Patent Application No. 2304596.6, filed on 29 March 2023, which is incorporated herein by reference in its entirety.

[0002] The present invention broadly relates to the field of battery technology. Specifically, the present invention relates to an electrolyte system, an electrochemical cell including an electrolyte system, a method for manufacturing an electrochemical cell, and an electrochemical cell assembly including at least one of an electrochemical cell. In particular, the present invention relates to an electrolyte system comprising a first electrolyte including a solid electrolyte, and a second electrolyte including a liquid electrolyte, a gel electrolyte, or a combination thereof. [Background technology]

[0003] The following description of the prior art is provided to place the present invention in its appropriate technical context and to enable a more complete understanding of its advantages. However, it should be understood that no discussion of prior art throughout this specification should be considered to be an explicit or implicit acknowledgment that such prior art is widely known or forms part of the general knowledge in the art.

[0004] In recent years, the demand for "green energy" has been increasing due to the harmful environmental impacts of fossil fuels. One energy source that is attracting significant attention is battery technology, particularly rechargeable batteries.

[0005] Of the generally available rechargeable battery technologies, lithium-ion (Li-ion) battery technology dominates the commercial market due to its high energy density compared to competing technologies such as nickel-cadmium batteries (Ni-Cd). However, Li-ion batteries are expensive to manufacture, highly flammable, and typically require the use of cobalt and / or nickel in the production of the cathode. Both cobalt and nickel are expensive materials, raising concerns about supply chain security. In addition, cobalt can be toxic if not handled properly, increasing the complexity of operations in both the manufacturing process and the end-of-life recycling process.

[0006] Recently, chalcogen and chalcogenized materials, particularly combinations of sulfur, selenium, and selenium sulfide, have attracted considerable attention due to their promising use in the cathodes of rechargeable lithium batteries.

[0007] In particular, lithium-sulfur (Li-S) cells are attracting widespread attention because they have advantages over lithium-ion batteries. For example, Li-S cells have higher mass energy (i.e., a measure of how much energy a battery contains in proportion to its weight, typically measured in "watt-hours / kilogram (Wh / kg)," where a watt-hour is a measure of electrical energy equivalent to 1 watt of consumption per hour), lower raw material costs, and are more environmentally friendly. Furthermore, they do not require the use of nickel or cobalt in their manufacture. In addition, there are safety advantages associated with using Li-S batteries over lithium-ion batteries. This is because the material does not require free metal ions. Instead, Li-S batteries proceed via a "conversion mechanism" in which sulfur and lithium react to form polysulfides.

[0008] In addition, lithium-selenium (Li-Se) cells are attracting attention because selenium has high conductivity. Li-Se cells also operate through a "conversion mechanism" in which selenium and lithium react to form polyselenium.

[0009] A drawback of conventional Li-S and Li-Se batteries is that polysulfides or polyseleniums generated at the electrodes dissolve in the liquid electrolyte, causing a "shutting effect" between the anode and cathode, leading to irreversible loss of sulfur / selenium from the cathode. This results in capacity loss and can be detrimental to the battery's cyclability (i.e., the measure of time it can be recharged before decomposition begins). Furthermore, another significant drawback of conventional Li-S and Li-Se batteries is the degradation of the liquid electrolyte during operation, due to the presence of lithium metal in the anode. As a result, a high-load liquid electrolyte is often required to enable extended battery cyclability. However, a high electrolyte load often leads to an increase in cell weight and volume, which negatively impacts the mass energy density and volumetric energy density (i.e., the amount of energy stored in the cell per liter of volume).

[0010] One way the shuttle effect of polysulfides and polyselenides is limited is by adding certain additives to the electrolyte, such as additives containing NO bonds (e.g., lithium nitrate (LiNO3)). While not bound by theory, it is understood that the presence of additives such as LiNO3 in the electrolyte causes the formation of a passivation layer on the anode (commonly known as the solid electrolyte interphase (SEI) layer) that mitigates the shuffling effect of polysulfides / polyselenides. However, there are many drawbacks associated with the use of these additives. For example, LiNO3 forms nitrogen oxide gas above 40°C, consequently narrowing the operating and storage temperature range. Furthermore, the presence of these additives causes cell expansion due to gas formation during cycling, not to mention safety implications. Therefore, the use of such additives should be eradicated or avoided.

[0011] Instead of using electrolyte salts such as LiNO3 or solid-state electrolytes, previous attempts have involved combinations of a low-porosity cathode with an electrochemically active sulfur component and a liquid electrolyte with little to no solubility of polysulfides (ultimately reducing polysulfide shuttling). However, such cells may suffer from the degradation of the liquid electrolyte during operation.

[0012] Furthermore, conventional Li-S batteries and Li-Se batteries often use flammable liquids as electrolytes, and their safety is a concern considering the high loads required to dissolve polysulfides and polyseleniums.

[0013] As a result, there is considerable interest in all-solid-state batteries (SSBs) that use inorganic solid-state electrolytes that do not dissolve polysulfides or polyseleniums during the battery cycle.

[0014] While using solid-state batteries improves safety, large-scale production of solid-state batteries is difficult. Solid-state batteries still have low sulfur utilization, poor interfacial contact between the electrolyte and electrodes, and potentially high impedance within the cell. Furthermore, large pressures are generally required to maintain good interfacial contact between the solid electrolyte and the cathode. There is also the problem of dendritic formation in solid lithium or sodium batteries. Lithium or sodium dendritic structures are tree-like microstructures that can form on the surface of the lithium or sodium metal anode during charge / discharge cycles. Solid electrolytes are often inherently brittle or polycrystalline, meaning they are susceptible to the growth of these dendritic structures. Dendritic formation is problematic because it affects the thermal stability of the cell and can cause short circuits. In some cases, lithium dendritic formation can cause pressure buildup and lead to explosions. Therefore, such dendritic formation affects the overall safety of the battery.

[0015] To address and overcome the drawbacks associated with solid-state batteries, research is being conducted on the combination of solid-state electrolytes with organic liquid electrolytes in lithium-ion and lithium-sulfur batteries. However, although such cells have better interfacial contact compared to solid-state batteries, they still require a high liquid electrolyte load.

[0016] Therefore, there remains a demand for electrochemical cells that not only have improved cyclability, enhanced safety, and a wide operating / storage temperature range, but also high mass energy density and volumetric energy density. To achieve this, there remains a demand to reduce the liquid electrolyte load on the cell and ensure that the possibility of degradation at the anode / electrolyte interface is minimized or completely prevented.

[0017] The objective of the present invention is to satisfy at least one of the above-mentioned needs, at least partially.

[0018] The object of the present invention is to overcome or improve upon one or more of the drawbacks of the prior art, or to provide at least a useful alternative. [Overview of the Initiative]

[0019] The following description conveys exemplary embodiments of the invention in sufficient detail to enable those skilled in the art to practice the invention. Features or limitations of the various embodiments described are not necessarily limited to other embodiments of the invention or the invention as a whole. Therefore, the following detailed description does not limit the scope of the invention, which is defined solely by the claims.

[0020] Therefore, in a first aspect of the present invention, an electrochemical cell comprising an anode, a cathode and an electrolyte system, wherein the electrolyte system is (i) A first electrolyte containing a solid electrolyte, (ii) A second electrolyte comprising a liquid electrolyte, a gel electrolyte, or a combination thereof, An electrochemical cell is provided in which the second electrolyte has sufficient polysulfide and / or polyselenide solubility to prevent shuttling, and the second electrolyte does not come into contact with the anode.

[0021] electrolyte system The electrolyte system defined by the first aspect of the present invention results in an electrochemical cell with superior mass energy and volume energy compared to existing hybrid cells. Such an electrolyte system has improved safety and cyclability compared to conventional Li-S cells, Li-Se cells, and conventional hybrid cells. In a preferred embodiment of the present invention, the first electrolyte acts as a physical barrier to prevent physical contact between the second electrolyte and the anode (meaning no decomposition of the second electrolyte during cycling), but also acts as a barrier to the formation of lithium or sodium dendritic material in the anode (if the anode contains lithium, sodium, a lithium-containing alloy, or a sodium-containing alloy).

[0022] Furthermore, the use of a second electrolyte that substantially does not dissolve polysulfides and / or polyseleniums means that a much more dilute electrolyte load can be used compared to existing hybrid systems that require an electrolyte load sufficient to dissolve sulfur / polysulfides and / or selenium / polyseleniums from the cathode. Thus, the electrolyte system according to the first aspect of the present invention provides an electrochemical cell having a high specific energy density (Wh / kg).

[0023] A “dilute” or “low” load of electrolyte means that a relatively small amount of liquid or gel electrolyte is used (in the context of the second electrolyte of this invention). In this invention, a relatively “dilute” or “low” load of liquid or gel electrolyte refers to an amount less than about 3 μL / mAh. As used herein, “μL / mAh” refers to the electrolyte / sulfur ratio in the cell (i.e., μL of electrolyte per milliampere-hour of sulfur).

[0024] Furthermore, the inventors understand that another advantage of liquid or gel electrolytes having low polysulfide solubility (or low solvent strength) is that the dissolution of the solid electrolyte by the liquid or gel electrode is reduced, improved, or completely eliminated. As those skilled in the art will understand, this advantage is further enhanced by the low-load liquid or gel electrolyte, which provides even greater protection against degradation of the solid electrolyte.

[0025] The term "electrolyte" has its usual meaning in this technical field and refers to a medium that enables ion transport between the anode and the cathode.

[0026] First electrolyte In some embodiments, the first electrolyte includes a ceramic material, a polymer material, or any combination thereof.

[0027] As used herein, the term "ceramic material" has the ordinary meaning in the art and refers to an inorganic nonmetallic solid composed of either a metal or a nonmetallic compound.

[0028] In certain embodiments, the first electrolyte includes a ceramic material selected from oxides, carbonates, nitrides, carbides, sulfides, oxysulfides, metal oxynitrides, metalloids, or any combination thereof.

[0029] The ceramic material may have a crystalline, polycrystalline, partially crystalline, or amorphous structure. Suitable ceramic materials include, but are not limited to, oxides, carbonates, nitrides, carbides, silicides, sulfides, oxysulfides, and / or oxynitrides of metals and / or metalloids. When the electrolyte system is incorporated into an electrochemical cell having an anode containing lithium metal or a lithium alloy, the ceramic material of the first electrolyte may contain lithium, and similarly, when the electrolyte system is incorporated into an electrochemical cell having an anode containing sodium metal or a sodium alloy, the ceramic material of the first electrolyte may contain sodium. However, all ceramic materials disclosed herein are compatible with all anode materials disclosed herein.

[0030] Non-limiting examples of suitable ceramic materials having sufficient ionic conductivity may be produced by various combinations of lithium compounds. Such lithium-containing ceramic materials include, but are not limited to, lithium oxide (Li2O, LiO, LiO2, LiRO2, where R is scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and / or lutetium), lithium carbonate (Li2CO3), lithium nitride (e.g., Li3N), lithium oxysulfide, lithium oxynitrogen, and lithium garnet-type oxides (e.g., Li7La3Zr2O). 12 )), Li 10 GeP2S 12 Examples include lithium phosphorus oxynitride, lithium silicon sulfide, lithium germanosulfide, lithium lanthanum oxide, lithium titanium oxide, lithium borosulfide, lithium aluminosulfide, lithium phosphorus sulfide, lithium silicate, lithium borate, lithium aluminate, lithium phosphate, lithium halides, and combinations thereof. In certain cases, the ceramic material comprises lithium oxide, lithium nitride, or lithium oxysulfide. In some embodiments, the ceramic comprises carbonate and / or carbides.

[0031] Examples of ceramic materials include, but are not limited to, Li 3.3 La 0.56 -containing oxides such as TiO3; NASICON structures such as LiTi(PO4)3; LiSICON (Li 14 Zn(GeO4)4); Li 10 GeP2S 12 ; garnet: Li7La3Zr2O 12 ; Li2O; other oxides such as Al2O3, TiO2, ZrO2, SiO2, ZnO; sulfides such as LiS-P2S5; antiperovskites such as Li3OCl; hydrides such as LiBH4, LiBH4-LiX (where X = Cl, Br, or I), LiNH, LiNH2, LiAlH6, Li2NH; borides or phosphates such as Li2B4O7, Li3PO4, LiPON; carbides or hydroxides such as Li2CO3, LiOH; fluorides such as LiF; nitrides such as Li3N; sulfides such as lithium borosulfide; lithium phosphosulfide, lithium aluminosulfide, oxysulfides, praseodymium oxide. At least one of the above-mentioned ceramic materials, or a combination thereof, may be used.

[0032] Optionally, the ceramic material is aludurite, lithium lanthanum zirconium oxide (Li7La3Zr2O 12 )(LLZO), lithium aluminum titanium phosphate (Li 1.3 Al 0.3 Ti 1.7 (PO4)3)(LATP), lithium aluminum germanium phosphate (LAGP), lithium phosphorus oxynitride (LIPON), lithium phosphorus sulfide (LPS), lithium germanium phosphorus sulfide (Li 10 GeP2S 12 )(LGPS), lithium phosphorus pentasulfide (Li2S-P2S5), selected from at least one of them. In some preferred embodiments, the ceramic material comprises aludurite.

[0033] As used herein, "aludurite" has the general formula Li 7-p BS6-p X p This refers to the material, where B is phosphorus or arsenic, X is chlorine, bromine, or iodine, and p is between 0 and 1. Optionally, B is phosphorus, X is chlorine, and p is 1 (i.e., argyrodite has the chemical formula Li6PS5Cl).

[0034] In some embodiments, the first electrolyte comprises a polymer material. Preferably, the polymer material is an intrinsically ionic conductive material, such as a sulfonated tetrafluoroethylene-based fluoropolymer copolymer (e.g., Nafion®). Alternatively, 10 -7 Polymers blended with lithium (or sodium) salts that can achieve bulk conductivity exceeding S / cm may also be used. Examples of suitable polymers include, but are not limited to, ethylene oxide (EO) polymers (e.g., PEO); acrylate polymers (e.g., PMMA); polyamines (e.g., polyethyleneimine); siloxanes (e.g., poly(dimethylsiloxane)); polyheteroaromatic compounds (e.g., polybenzimidazole); polyamides (e.g., nylon); polyimides (e.g., Kapton®); polyvinyl (e.g., polyacrylamide, poly(2-vinylpyridine), poly(N-vinylpyrrolidone), poly(methylcyanoacrylate), poly(vinyl acetate), poly(vinyl alcohol), poly(vinyl chloride), poly(vinyl fluoride)); inorganic polymers (e.g., polysilane, polysilazane, polyphosphazene, polyphosphonate); polyurethane; polyolefins (e.g., polypropylene, polytetrafluoroethylene); polyesters (e.g., polycarbonate, polybutylene terephthalate); or combinations thereof. Optionally, coblock polymers such as sulfonated tetrafluoroethylene-based fluoropolymer copolymers (e.g., Nafion®) may be used. At least one of the polymer materials described above, or a combination thereof, may be used.

[0035] In some embodiments, the first electrolyte may include ceramic particles in combination with one or more polymer materials disclosed herein.

[0036] In some embodiments, the first electrolyte may include a ceramic-polymer composite material. Examples of ceramic-polymer composite materials include, but are not limited to, metalcone (e.g., alcone, zincone, zircone, titacone, or combinations thereof).

[0037] The term "composite material" has its usual meaning in the relevant art and refers to a material made from two or more constituent materials having different chemical or physical properties. When two or more constituent materials are combined, the resulting composite material has properties different from those of the individual components present.

[0038] In some embodiments, the first electrolyte is argyrodite, lithium germanium phosphate sulfide (LGPS-Li 10 GeP2S 12 ), comprising one or more of the following: lithium phosphorus sulfide (LPS), lithium lanthanum zirconium oxide (LLZO), lithium aluminum germanium phosphate (LAGP), lithium phosphorus oxynitride (LIPON), polyethylene oxide (PEO), or a combination thereof.

[0039] In some preferred embodiments, the first electrolyte comprises an argyrodite. Argyrodites have high ionic conductivity and are easily processable. In addition, argyrodites have high compatibility with the anode and cathode materials discussed herein. Although not bound by theory, it is understood that argyrodites are highly compatible with Li-S battery technology due to their low voltage range (typically 1-3V) compared to Li-ion batteries (which can exceed 4V). Furthermore, the material exhibits good stability at the interface with the anode when it is part of an electrochemical cell. Optionally, the first electrolyte comprises an argyrodite with the chemical formula Li6PS5Cl.

[0040] In some embodiments, the first electrolyte further comprises a binder. The binder may include a copolymer. The copolymer may be a block copolymer. The binder may include a copolymer having repeating units comprising a carboxylic acid group or a conjugate base.

[0041] In some embodiments, the solid electrolyte comprises two or more binders. For example, the solid electrolyte may comprise two or more binders, three or more binders, four or more binders, or five or more binders.

[0042] In some embodiments, the binder includes poly(ethylene-co-acrylic acid), carboxylated polystyrene, poly(ethylene-co-methacrylic acid), carboxylated rubber (e.g., carboxylated nitrile butadiene rubber or carboxylated styrene butadiene rubber), or any combination thereof.

[0043] It is understood that the presence of at least one binder improves the elasticity of the first electrolyte and therefore improves its processability. In addition, the presence of at least one binder may also help to keep the first electrolyte layer intact when the cell is assembled and / or during operation.

[0044] As those skilled in the art will understand, the assembly and operation of a cell can induce mechanical stress on its components. For example, some causes of mechanical stress may include lithium diffusion, heat, or shock. Such stress can cause some degree of damage to the solid electrolyte (e.g., promoting the formation of lithium or sodium dendrites during operation). However, it is understood that the presence of a binder may reduce such risks. The binder may be present in the range of 0.1–15% of the total weight of the first electrolyte, often in the range of 1–10%, and often in the range of 2–7%.

[0045] In some embodiments, the first electrolyte comprises an argyrodite and a binder selected from poly(ethylene-co-acrylic acid), carboxylated polystyrene, poly(ethylene-co-methacrylic acid), carboxylated nitrile butadiene rubber, carboxylated styrene butadiene rubber, or a combination thereof.

[0046] In some embodiments, the ionic conductivity of the first electrolyte may be in the range of 0.0001 mS / cm to 10 mS / cm, or 0.05 mS / cm to 7 mS / cm, or 0.75 mS / cm to 5 mS / cm, or 1 mS / cm to 7.5 mS / cm, or approximately 0.0001, 0.0005, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or 10 mS / cm, or any range within these ranges. Ionic conductivity within these ranges results in an electrochemical cell with superior capacity at higher discharge rates. Ionic conductivity may be measured using any known technique, such as a high-temperature conductivity cell (HTCC) or impedance spectroscopy.

[0047] In some embodiments, the thickness of the first electrolyte is in the range of 5 μm to 100 μm, often in the range of 10 μm to 80 μm, or in the range of 15 μm to 70 μm, or in the range of 20 μm to 60 μm, or in the range of 30 μm to 50 μm, or approximately 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100 μm, or any range within these. Thicknesses within these ranges provide a lighter electrochemical cell without compromising cyclability and cell safety.

[0048] Optionally, the porosity of the first electrolyte is less than 30%, less than 10%, or less than 1%. In some embodiments, the porosity of the first electrolyte may be in the range of 1% to 40%, or 1% to 10%, or 1% to 5%, or about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40%, or any range thereof. A first electrolyte having a porosity within this range is thought to enable the first electrolyte to function as a lithium and / or sodium dendritic barrier, and to prevent the second electrolyte from diffusing to the anode and causing any physical degradation.

[0049] "Porosity" refers to the volume fraction of a material that is void or empty space relative to its total volume, and is expressed as a percentage between 0% (no void or empty space) and 100% (completely void or empty space). Each pore in the material may be discrete (i.e., completely embedded in the material or accessing a single surface of the material) or continuous (i.e., accessing two or more surfaces of the material). In some embodiments of the present invention, the first electrolyte contains no or only a small number of continuous pores that would allow contact between the second electrolyte and the anode.

[0050] Second electrolyte A second electrolyte according to a first aspect of the present invention comprises a liquid electrolyte, a gel electrolyte, or a combination thereof, and has sufficient polysulfide and / or polyselenide solubility to prevent shuttling.

[0051] As those skilled in the art recognize, and as described above, the "shutting effect" can occur in electrolytic cells containing sulfur and selenium, thereby allowing dissolved polysulfides (or polyselenides) to dissolve in the electrolyte, diffuse through the electrolyte, and ultimately come into irreversible contact with the anode. This loss of sulfur or selenium from the cathode can cause a loss of capacity and cycle stability and is therefore preferably avoided. Accordingly, it is desirable to provide electrolytes, particularly liquid electrolytes, that have low solubility for polysulfide or polyselenide species.

[0052] Accordingly, in the present invention, the second electrolyte has low solubility for polysulfide and / or polyselenide species, in particular, sufficient solubility to prevent or improve, or at least significantly or substantially reduce, the shuttling effect in the electrolytic cell. As those skilled in the art will understand, it is not necessary to prevent or reduce, or at least significantly or substantially reduce, the shuttling effect by complete precipitation (i.e., insolubility) of the polysulfide or polyselenide species generated at or near the cathode. However, in order to sufficiently prevent significant shuttling, the dissolution of substantial amounts of the generated polysulfide or polyselenide species into the liquid electrolyte must be limited, or their diffusion to other anodes must be suppressed, which can be achieved by providing a liquid electrolyte with low solubility for these species.

[0053] In some embodiments, the second electrolyte is defined as having a low (or relatively low) concentration at room temperature (approximately 20°C), such as less than 2M, less than 1M, less than 750mM, less than 500mM, less than 400mM, less than 200mM, less than 150mM, less than 100mM, less than 10mM, or less than 1mM. It may be soluble in lysulfides and / or polyseleniums, or in concentrations of about 1 M to about 500 mM, or about 750 mM to about 250 mM, or about 1 mM to about 500 mM, or about 2 mM to about 250 mM, or about 5 mM to about 100 mM, or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 20, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 43 The concentrations may be 0, 440, 450, 460, 470, 480, 490, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950 mM, or approximately 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3 M, or any range thereof. If the second electrolyte of the present invention has solubility for polysulfides or polyselenides as provided above, the shuttling effect is expected to be substantially or completely prevented, or at least significantly or substantially reduced. In some embodiments, the electrolyte may not dissolve polysulfides and / or polyselenides, or may substantially not dissolve polysulfides and / or polyselenides. For example, the electrolyte may have solubility for polysulfides and / or polyselenides in the range of about 0.001 mM to about 50 mM, or about 0.01 to about 40 mM, or about 0.1 mM to about 20 mM, or about 1 mM to about 10 mM.In response to this, the second electrolyte may generally have low solubility towards sulfur-containing species (such as polysulfides and sulfur) or selenide-containing species (such as polyselenium and selenium).

[0054] As those skilled in the art will understand, the use of a second electrolyte with low, poor, or no solubility of polysulfides and / or polyselenides can prevent the shuttle of polysulfides and / or polyselenides within the electrolyte, and is therefore beneficial in cells such as lithium-sulfur cells, lithium-selenium cells, or lithium-selenium sulfide cells. As mentioned above, the shuttle effect of polysulfides / polyselenides is an undesirable reaction because it can cause a loss of Coulomb efficiency and affect cyclability.

[0055] The second electrolyte of the present invention typically comprises a suitable solvent system, a liquid or gel, or a mixture of liquids and / or gels, and at least one alkali metal salt.

[0056] Suitable organic solvents for use as the second electrolyte include: ethers (e.g., linear ethers, diethyl ether (DEE), diglyme (e.g., 2-methoxyethyl ether), tetraglycerides, tetrahydrofuran, 2-methyltetrahydrofuran, dimethoxyethane (DME), dioxolane (DIOX)); carbonates (e.g., dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethylene carbonate (EC), propylene carbonate (PC)); sulfones (e.g., dimethyl sulfone (DMS), ethyl methyl sulfone (EMS), tetramethyl sulfone (TMS)); esters (e.g., methyl formate, ethyl formate, methyl propionate, methyl propionate) Examples of solvents include propyl, ethylpropyl propionate, ethyl acetate, and methyl butyrate; ketones (e.g., methyl ethyl ketone); nitriles (e.g., acetonitrile, propionitrile, isobutyronitrile); amides (e.g., dimethylformamide, dimethylacetamide, hexamethylphosphoramide, N,N,N,N-tetraethylsulfamide); lactams / lactones (e.g., N-methyl-2-pyrrolidone, butyrolactone); ureas (e.g., tetramethylurea); sulfoxides (e.g., dimethyl sulfoxide); phosphates (e.g., trimethyl phosphate, triethyl phosphate, tributyl phosphate); phosphoramides (e.g., hexamethylphosphoramide); or at least one of any combination thereof. Further preferred solvents include toluene, benzene, heptane, xylene, dichloromethane, and pyridine.

[0057] In some embodiments, the second electrolyte may optionally include one or more ethers, carbonates, sulfones, esters, ketones, nitriles, amides, lactams, ureas, phosphates, and phosphoramides, which are halogenated, for example, they may optionally be fluorinated, and / or optionally chlorinated, and / or optionally iodized, and / or optionally brominated.

[0058] In certain embodiments, the second electrolyte comprises a mixture of a halogenated solvent and a non-halogenated solvent. For example, the organic solvent may optionally comprise one or more ethers and fluorinated ethers, or a mixture of one or more carbonates and fluorinated carbonates.

[0059] Non-limiting examples of fluorinated ethers include 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), hydrofluorinated ethers (HFE), and 2,2,2-trifluoroethyl methyl ether ethylene glycol (TFEG). An example of a fluorinated carbonate is monofluoroethylene carbonate. Non-limiting examples of chlorinated ethers include dichlorodiethyl ether and perchlorodiethyl ether. An example of an ether that is both a fluorinated and chlorinated ether is isoflurane. An example of a chlorinated carbonate is chloroethylene carbonate. Those skilled in the art will readily be able to deduce other halogenated solvents that may be suitable for use.

[0060] In some embodiments, the second electrolyte may include one or more ionic liquids as solvents. The ionic liquids mentioned above include organic cations such as imidazolium, ammonium, pyrrolidinium, and / or bis(trifluoromethanesulfonyl)imide TFSI - , bis(fluorosulfonyl)imide FSI - Triflate, tetrafluoroborate BF4 - , dicyanamide DCA - Chloride Cl -It may also contain organic anions such as [list of anions]. Ionic liquids are liquid at room temperature (20°C). Examples of suitable ionic liquids include (N,N-diethyl-N-methyl-N(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl), N,N-diethyl-N-methyl-N-propylammonium bis(fluorosulfonyl)imide, N,N-diethyl-N-methyl-N-propylammonium bis(fluorosulfonyl)imide, N,N-dimethyl-N-ethyl-N-(3-methoxypropyl)ammonium bis(fluorosulfonyl)imide, N,N-dimethyl-N-ethyl-N-(3-methoxypropyl)ammonium bis(trifluoromethanesulfonyl), N,N-dimethyl-N-ethyl-N-benzylammonium bis(trifluoromethanesulfonyl), N,N-dimethyl-N-ethyl-N-phenylethylammonium bis(trifluoromethanesulfonyl), N-ethyl-N,N-dimethyl-N-(2-methoxyethyl)ammonium bis(fluorosulfonyl), N-ethyl-N,N-dimethyl-N-(2-methoxyethyl)ammonium bis(trif (N,N-Diethyl-N-methylammonium bis(trifluoromethanesulfonyl)imide, N-Tributyl-N-methylammonium dicyanamide, N-Tributyl-N-methylammonium iodide, N-Trimethyl-N-butylammonium bis(trifluoromethanesulfonyl)imide, N-Trimethyl-N-butylammonium bromide, N-Trimethyl-N-hexylammonium bis(trifluoromethanesulfonyl)imide, N-Trimethyl-N-propylammonium bis(fluorosulfonyl)imide, N-Trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide, (N,N-Diethyl-N-methyl-N(2-methoxyethyl)ammonium bis(fluorosulfonyl)imide, 1-Butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, 1-Ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-Methyl-1-(2-methoxyethyl)pyrrolidinium bis(fluorosulfonyl)imide, N,Examples include N-diethyl-N-methyl-N-propylammonium bis(fluorosulfonyl)imide, N-ethyl-N,N-dimethyl-N-(2-methoxyethyl)ammonium bis(fluorosulfonyl)imide, N-propyl-N-methylpiperidinium bis(fluorosulfonyl)imide, N-trimethyl-N-butylammonium bis(fluorosulfonyl)imide, N-methyl-N-butyl-piperidinium bis(trifluoromethanesulfonyl)imide, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, or combinations thereof.

[0061] Alternatively, or in addition, the second electrolyte may be a gel electrolyte. As used herein, the term “gel electrolyte” refers to an electrolyte in which the liquid is in a gel matrix, where “gel” is understood to be an amorphous liquid that is stationary or non-flowing when measured at room temperature (i.e., 20°C or about 20°C). As those skilled in the art will understand, any gel may melt at higher temperatures or high temperatures, such as those experienced by electrolytic cells in use, because the kinetic energy of the gel component exceeds the intermolecular and intramolecular forces that result in gelation. In some embodiments, it would be advantageous to provide an electrolyte that is a gel at room temperature (i.e., when not in use), then melts into a liquid at a high operating temperature, and then regelates as the temperature subsequently decreases. In some embodiments, the gel electrolyte may comprise a liquid electrolyte that gels, such as polyethylene oxide having an ether, such as dimethyl ether. In one example, the gel electrolyte may comprise polyethylene oxide in combination with LiTFSI in dimethyl ether.

[0062] In certain embodiments, the second electrolyte is linear ether, diethyl ether (DEE), tetrahydrofuran (THF), dimethoxyethane (DME), dioxolane (DIOX), diglyme, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), methyl formate (MF), ethyl formate (EF), methyl propionate (MP), ethyl acetate (EA), and methyl butyrate (MB), methyl ethyl ketone, acetonitrile (ACN), propionitrile (PN), isobutyronitrile (iBN), dimethylformamide (DMF), and dimethyl The solution comprises a solvent selected from acetamide (DMAc), N-methyl-2-pyrrolidone (NMP), tetramethylurea (TMU), dimethyl sulfoxide (DMSO), trimethyl phosphate, triethyl phosphate, hexamethylphosphoramide, toluene, benzene, heptane, xylene, dichloromethane, ionic liquids, fluorinated ethers, fluorinated carbonates, fluorinated sulfones, fluorinated esters, fluorinated ketones, fluorinated nitriles, fluorinated amides, fluorinated lactams, fluorinated ureas, fluorinated phosphates, fluorinated phosphoramides, gels, or combinations thereof, and at least one alkali metal salt.

[0063] Any combination of one or more of the solvents described above may be included in the second electrolyte. For example, the second electrolyte may include a combination of an ionic liquid and a fluorinated ether, or a combination of ionic liquids in a gel, or a combination of fluorinated ethers in a gel. Those skilled in the art will likely be able to prepare the solvent system appropriately and routinely as needed.

[0064] The second electrolyte may include a combination of two or more of the liquids and / or gels described in detail above.

[0065] In some embodiments, when the anode contains lithium or a lithium alloy, the alkali metal salt contains lithium. In other embodiments, when the anode contains sodium or a sodium alloy, the alkali metal salt contains sodium.

[0066] If the alkali metal salt contains lithium, the alkali metal salt may be at least one lithium salt selected from lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium perchlorate, lithium sulfate, lithium nitrate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethane)sulfonimide, lithium bis(fluorosulfonyl)imide, lithium bis(oxalate)borate, lithium difluoro(oxalate)borate, lithium bis(pentafluoroethanesulfonyl)imide, lithium 2-trifluoromethyl-4,5-dicyanoimidazole, and combinations thereof, or If the potassium metal salt contains sodium, it may be at least one sodium salt selected from sodium hexafluoroarsenate, sodium hexafluorophosphate, sodium perchlorate, sodium sulfate, sodium nitrate, sodium trifluoromethanesulfonate, sodium bis(trifluoromethane)sulfonimide, sodium bis(fluorosulfonyl)imide, sodium bis(oxalic acid)borate, sodium difluoro(oxalic acid)borate, sodium bis(pentafluoroethanesulfonyl)imide, sodium 2-trifluoromethyl-4,5-dicyanoimidazole, or any combination thereof.

[0067] In some embodiments, the alkali metal salts are lithium trifluoromethanesulfonate (also known as thyrium triflate or LiOTf), lithium bis-trifluoromethanesulfonimide (LiTFSI), and / or lithium bis(fluorosulfonyl)imide (LiFSI). In conventional Li-S cells, LiFSI would typically be considered unsuitable because it lacks stability in the presence of polysulfides. However, in the cathodes of the present invention, detailed below, which operate without the formation of polysulfides, the electrolytes may include salts such as LiFSI and solvents that would otherwise be unstable, resulting in a wider range of materials that can be used in the manufacture of the claimed cells.

[0068] As those skilled in the art will recognize, any suitable mechanism can be implemented to ensure low (or relatively low) polysulfide and / or low polyselenide solubility in the second electrolyte (i.e., sufficient to prevent or reduce, or at least significantly or substantially reduce, the shuttling effect). For example, low (or relatively low) solubility may be achieved by selecting a solvent, ionic liquid, and / or gel in which the polysulfide and / or polyselenide are insoluble or substantially insoluble. Alternatively, or similarly, it is known that increasing the concentration of the dissolved salt in the solvent can reduce the solubility of the analyte in the solvent system, via the "common ion effect," etc.

[0069] Therefore, in some embodiments, the concentration of at least one alkali metal salt is at least 75% of the saturation concentration of the electrolyte. As used herein, the term “saturation concentration” refers to the degree of solubility of a particular solute in a particular solvent. The saturation point is the point at which the concentration does not increase when a solute is added. In certain embodiments, the concentration of at least one alkali metal salt may be at least 80% of the saturation concentration of the solvent system, or at least 85% of the saturation concentration of the solvent system, or at least 90% of the saturation concentration of the solvent system, or about 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 98.5, 99, 99.5, 99.9 or 99.99%, or any range thereof. The concentration of at least one alkali metal salt may be about 100% of the saturation concentration, i.e., the electrolyte may be completely or substantially saturated with the alkali metal salt. In some embodiments, the concentration of the alkali metal salt in the electrolyte may be in the range of 75% to 90%, or 80% to 100%, or 80% to 90%, or 85% to 95%, or 90% to 99% of the saturation concentration of the solvent system. For example, the concentration of the lithium salt or sodium salt in the electrolyte may be in the range of 0.05 M to 10 M, or 1 M to 5 M, or 2 M to 4 M, e.g., about 3 M. The lithium salt may be present in the electrolyte at a concentration in the range of 0.1 M to 6 M, or 0.5 M to 5 M, or 1 M to 4 M, or 2.5 M to 3.5 M, e.g., about 3 M.

[0070] As those skilled in the art will understand, saturation concentration is generally determined at room temperature, for example, about 20°C. The saturation concentration of polysulfides and / or polyselenides in a particular solvent may be determined by known methods, for example, by determining the point at which just enough electrolyte is added to dissolve all the solid residue.

[0071] In embodiments of the present invention having a high dissolved salt concentration in the second (i.e., liquid or gel) electrolyte, such as those described above having a salt saturation of at least 75%, it is further expected that such a liquid electrolyte will have a protective effect on the first (i.e., solid) electrolyte. Not bound by any particular theory, it is understood that a liquid electrolyte with a high salt concentration may significantly prevent not only the dissolution of polysulfides and / or polyselenides, but also the dissolution or degradation of the solid electrolyte, particularly in embodiments where the first (i.e., solid) electrolyte is a ceramic material susceptible to degradation by liquid solvents such as argyrodite or lithium phosphate (LPS).

[0072] An advantage of the present invention is that a low or dilute level of a second (i.e., liquid or gel) electrolyte is present in the electrolyte system of the present invention. In some preferred embodiments, the electrolyte load of the second electrolyte is up to about 3 μL / mAh, for example, in the range of about 0.1 μL / mAh to about 3 μL / mAh, or in the range of about 0.3 μL / mAh to about 2.5 μL / mAh, or in the range of about 0.5 μL / mAh to about 2 μL / mAh. Typically, conventional Li-S and Li-Se electrolytic cells require a large amount (i.e., a high load) of electrolyte to dissolve the polysulfide and / or polyselenium contained in the cathode. The cell according to the present invention advantageously does not require a high electrolyte load compared to conventional cells. As those skilled in the art will understand, a low electrolyte load is beneficial because it makes the overall cell lighter and results in higher mass energy. While not bound by any particular theory, the inventors understand that a combination of a polysulfide (or polyselenide) insoluble liquid or gel electrolyte combined with a low-porosity solid electrolyte allows for the use of a low-load liquid or gel electrolyte, thereby increasing the mass energy.

[0073] Electrochemical cell Advantageously, the electrochemical cell according to the present invention has superior mass energy density and volumetric energy density compared to existing hybrid cells, which is at least partially provided by a reduction in liquid electrolyte load. Furthermore, such cells are expected to have improved safety and cyclability compared to conventional Li-S cells or Li-Se cells, for the following reasons: - The volume of solvent present in the liquid portion of the electrolyte system is reduced, increasing the safety of the cell during use (where flammable or explosive solvents are required). - The first electrolyte with low porosity acts as a physical barrier to prevent physical contact between the second electrolyte and the anode (meaning no decomposition of the second electrolyte during the cycle), but also acts as a barrier to the formation of lithium or sodium dendritic material. - The second electrolyte is selected such that the first electrolyte is not decomposed or dissolved.

[0074] While not bound by theory, the charge and discharge cycles of the electrochemical cell according to the present invention are thought to operate via a solid-state (or pseudo-solid-state, or quasi-solid-state, or solid-state-like) mechanism. This beneficial solid-state (or solid-state-like) mechanism may arise through the formation of solid (i.e., non-solvable) polysulfide and / or polyselenium species in a low-solubility second electrolyte, thereby approximating a solid-state electrolyte when used in combination with a solid electrolyte. In such solid-state or solid-state-like systems, the cathodes of conventional Li-S / Li-Se cells and Li-S / Li-Se solid-state cells may have insufficient transport of lithium and / or sodium ions to the active sulfur and / or selenium species present in the cathode, and / or an inadequate cathode interface to allow for high sulfur / selenium utilization via the solid-state mechanism. However, the use of an electrolyte system according to a first embodiment of the present invention in the electrochemical cell (i.e., a first electrolyte including a solid electrolyte combined with a second electrolyte including a liquid electrolyte, a gel electrolyte, or a combination thereof having low polysulfide and / or selenide solubility) is expected to beneficially mitigate this problem through the formation of solid polysulfide and / or solid polysulfide species remaining in or near the cathode. The inventors also anticipate that other properties of polysulfide and / or polyselenium species may also contribute to inhibiting the “shutting” effect, such as the lack of ionic charge on polysulfide / polyselenium species present in the second electrolyte (particularly a liquid electrolyte with a high solubility salt concentration) or on specific species formed (such as longer-chain polysulfides that preferentially form in the liquid electrolyte).

[0075] The term "anode" has its usual meaning in this art and refers to the negative electrode of a cell. The anode releases electrons into the circuit (and effectively oxidizes) during an electrochemical reaction.

[0076] The term "cathode" has its usual meaning in the art and refers to the positive electrode of a cell. The cathode acquires (and is effectively reduced to) electrons from the circuit during an electrochemical reaction.

[0077] In some embodiments, the first electrolyte has a first surface and a second opposing surface, the first surface being in contact with the anode surface and the second surface being in contact with the second electrolyte. At least a portion of the first surface of the first electrolyte may be in direct contact with at least a portion of the anode surface. As used herein, the term “direct contact” means that there is no additional layer or material between the first surface of the first electrolyte and the anode. Such a structure means that the second electrolyte does not come into contact with the anode, especially when a first electrolyte with low porosity (as described above) is used. Thus, in the electrolytic cell of the present invention, as is common in known cells utilizing hybrid electrolytes, there may be no liquid electrolyte, gel electrolyte, or combination thereof as claimed herein, between the solid electrolyte and the anode, in contact with the anode, or distributed throughout the first electrolyte.

[0078] As used herein, the term “surface” takes its ordinary meaning and refers to the exterior of an object, layer, or structure. In some embodiments, the first electrolyte would be substantially planar, in the sense that it includes a sheet material or a layer applied directly or indirectly to the surface of an anode.

[0079] In certain embodiments, the cell further includes an additional first electrolyte positioned on the opposing surface of the anode, so that the anode is positioned between two distinct first electrolytes. Often, at least a portion of each surface of the anode is in direct contact with the two distinct first electrolytes.

[0080] In some embodiments, the electrochemical cell includes a separator. The separator may be formed from a wide variety of materials. Examples of materials used for the separator include, but are not limited to, polyolefin materials such as polyethylene, polypropylene, or combinations thereof.

[0081] anode In some embodiments, an electrochemical cell according to a first aspect of the present invention is provided, wherein the anode comprises an alkali metal, an alkali metal alloy, silicon, carbon, or a silicon-carbon composite material.

[0082] In certain preferred embodiments, the alkali metal or alkali metal alloy includes lithium and / or sodium. In some embodiments, the anode includes a foil formed from lithium metal or a lithium metal alloy. Examples of lithium alloys include, but are not limited to, lithium indium alloy, lithium aluminum alloy, lithium magnesium alloy, and lithium boron alloy. In other embodiments, the anode includes a foil formed from sodium metal or a sodium metal alloy. Examples of sodium alloys include, but are not limited to, sodium indium alloy, sodium aluminum alloy, sodium magnesium alloy, and sodium boron alloy. Generally, the anode is a lithium metal foil or a sodium metal foil due to their high specific capacity.

[0083] In some embodiments, the anode may contain silicon. If the anode contains silicon, it may be lithiated or sodiated. As used herein, the term “lithiated” has its usual meaning in the art and refers to combination with or impregnation with lithium or a lithium compound. Similarly, the term “sodioated” has its usual meaning in the art and refers to combination with or impregnation with sodium or a sodium compound. Preferably, the lithiating or sodiating step is performed before the assembly of the electrolytic cell (i.e., the silicon contains lithium ions or sodium ions before the initial charge / discharge cycle).

[0084] In some embodiments, the anode may contain carbon, for example, carbon nanotubes, carbon nanofibers, graphene, graphene oxide, graphite, carbon black, or a combination thereof. The carbon-containing anode may also be lithiated or sodiated in some embodiments.

[0085] In some embodiments, the anode may include a silicon-carbon composite material. Examples of silicon-carbon composite materials include, but are not limited to, silicon-doped graphite. The composite silicon-carbon anode may also be lithiated or sodiated in some embodiments.

[0086] Cathode In some embodiments, the cathode comprises (i) selenium, sulfur, or a combination thereof, and (ii) a carbonaceous material, metallic material, semimetallic material, polymer, or a combination thereof. In such embodiments, the cathode may contain at least about 40% by weight of sulfur and / or selenium based on the total weight of the cathode, or at least about 60% by weight, at least about 70% by weight, or at least about 75% by weight of sulfur and / or selenium, or the cathode may contain 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99% by weight of sulfur and / or selenium, or any range therein, based on the total weight of the cathode.

[0087] The cathode may be porous, where “porosity” and “porosity” have the same meanings as above for the first electrolyte. In some embodiments, the porosity of the cathode may be in the range of about 10% to about 60%, or about 15% to about 45%, or about 20% to about 40% by weight, for example, about 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, or 40% by weight, or any range therein. These porosity ranges provide a good balance between the penetration of the second electrolyte into the cathode and the structural integrity of the cathode.

[0088] The cathode may include a solid comprising at least one of carbonaceous materials, metallic materials, semimetallic materials, polymers, or any combination thereof. The solid may be in the range of at least about 10% by weight, at least about 20% by weight, or at least about 30% by weight, or about 10% to about 20% by weight, or about 15% to about 30% by weight, or 0.1 to 30% by weight, or about 1% to about 20% by weight, or about 5% to about 10% by weight, for example, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, It may be present in the cathode at levels of 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40% by weight, or any range within that range.

[0089] In one embodiment, the cathode may include (i) selenium, sulfur, or a combination thereof, and (ii) a carbonaceous material, a metallic material, a metalloid, a polymer, or a combination thereof, and is in the form of a composite material.

[0090] As stated above, the term “composite material” has the common meaning in the art and refers to a material made from two or more constituent materials having different chemical or physical properties. When two or more constituent materials are combined, the resulting composite material has properties different from those of the individual components present. Composite materials can be manufactured by known techniques such as melt diffusion, solution-based processes, mechanical grinding, or any method known to those skilled in the art. Annealing can be carried out as an optional step after the melt diffusion step.

[0091] In some embodiments, the cathode includes carbon-sulfur composites, metal sulfides, polymer-sulfur composites, carbon-selenium composites, carbon-sulfur-selenium composites, metal selenides, polymer-selenium composites, metal sulfoselenides, metalloid sulfides, metalloid selenides, or combinations thereof.

[0092] If present, the carbonaceous material may contain micropores, mesopores, or a combination of micropores and mesopores. In such embodiments, the micropores would have a pore diameter in the range of 0.1 nm to 2 nm, often in the range of 0.5 nm to 1.5 nm. Optionally, the mesopores would have a pore diameter in the range of 2 nm to 50 nm, often in the range of 5 nm to 30 nm. As used herein, the term "nm" has its usual meaning and is a symbol indicating the length unit "nanometer".

[0093] If present, carbonaceous materials may include carbon black (e.g., acetylene black, channel black, furnace black, lamp black, and thermal black), activated carbon, graphene, reduced graphene oxide, carbon nanofibers, carbon nanotubes (CNTs), multiwall carbon nanotubes (MWCNTs), microporous carbon, mesoporous carbon, carbon containing micropores and mesopores, or combinations thereof. As used herein, the term "graphene" is intended to include two-dimensional and three-dimensional graphene. In some embodiments, graphene may be three-dimensional. Carbonaceous materials are generally understood to have very high conductivity, resulting in high charge / discharge capacity.

[0094] As used herein, the term "microporous" has its usual meaning in the art and refers to a material containing interconnected pores (i.e., micropores) with a size of less than 2 nm. As used herein, the term "mesoporous" has its usual meaning in the art. For example, according to IUPAC nomenclature, a mesoporous material is a nanoporous material containing pores (i.e., mesopores) having a diameter of 2 nm to 50 nm.

[0095] In some embodiments, the carbonaceous material may be further doped with heteroatoms. Examples of dopants include, but are not limited to, nitrogen, boron, oxygen, sulfur, or phosphorus. In preferred embodiments, the carbonaceous material is boron-doped, or the carbonaceous material is boron-doped graphene. While not bound by any theory, it is understood that doping the carbon network structure increases the conductivity of the carbonaceous material and further improves the mechanical rigidity of the resulting cathode.

[0096] If present, the metallic material may include metals, metal oxides, metal hydroxides, metal sulfides, or combinations thereof.

[0097] As used herein, the term “metal” is intended to include all metallic elements, including transition metals and poor metals, alkali metals, alkaline earth metals, lanthanides, and actinides. Examples of metals include, but are not limited to, nickel, manganese, platinum, silver, gallium, copper, palladium, or combinations thereof. Examples of metal oxides include, but are not limited to, zinc oxide, aluminum oxide, titanium oxide, vanadium oxide, ruthenium oxide, nickel oxide, manganese oxide, or combinations thereof. In many cases, metal oxides include manganese oxide. Examples of metal hydroxides include, but are not limited to, cobalt(II) hydroxide, nickel(II) hydroxide, or combinations thereof. Examples of metal sulfides include, but are not limited to, molybdenum sulfide. Metallic materials enable cathodes with high structural rigidity and conductivity.

[0098] Where present, metalloid materials may include metalloids, metalloid oxides, metalloid sulfides, metalloid nitrides, or combinations thereof. As used herein, “metalloid” has the same meaning in the art to refer to a chemical element having characteristics between metal and nonmetal. Examples of metalloids include, but are not limited to, silicon, boron, germanium, antimony, arsenic, tellurium, or combinations thereof. Examples of metalloid oxides include, but are not limited to, silicon oxide, germanium oxide, boron oxide, or combinations thereof. Examples of metalloid sulfides include, but are not limited to, boron sulfide, germanium sulfide, antimony sulfide, or any combination thereof. Examples of metalloid nitrides include, but are not limited to, boron nitride, germanium nitride, antimony nitride, tellurium nitride, or combinations thereof. Optionally, boron nitride may be in the form of boron nitride aerogel, boron nitride nanomesh, or boron nitride nanotubes. In a preferred embodiment, the semimetallic material includes boron nitride nanotubes.

[0099] If polymer materials are present, they include polyacrylonitrile; cellulose; polyethers (examples include, but are not limited to, polyethylene glycol (PEG)); polyvinylpyrrolidone (PVP); poly(3,4-ethylenedioxythiophene) (PEDOT); poly(3,4-ethylenedioxythiophene); polystyrene sulfonate (PEDOT:PSS); polythiophene (PTh); polydopamine (PDA); polyaniline (PANI); triallyl isocyanurate polymers; polypyrrole (PPY); ionomers (examples include, but are not limited to, sulfonated tetrafluoroethylene-based fluoropolymer copolymers (Nafion®), and copolymers of ethylene and acrylic acid and / or methacrylic acid); ethylene oxide (EO) polymers (examples include, but are not limited to, PEO); acrylate polymers (examples include, but are not limited to, PMMA); polyamines (examples include, but are not limited to, polyethyleneimine); siloxanes (examples include, but are not limited to, poly(dimethyl) Examples include siloxanes); polyheteroaromatic compounds (examples include, but are not limited, polybenzimidazole); polyamides (examples include, but are not limited, nylon); polyimides (examples include, but are not limited, Kapton®); polyvinyl polymers (examples include, but are not limited, poly(2-vinylpyridine), poly(vinyl acetate), poly(vinyl alcohol), poly(vinyl chloride), and poly(vinyl fluoride)); polycyanoacrylates (examples include, but are not limited, poly(methylcyanoacrylate)); inorganic polymers (examples include, but are not limited, polysilane, polysilazane, polyphosphazene, and polyphosphonate); polyurethanes; polyolefins (examples include, but are not limited, polyacrylamide, polypropylene, and polytetrafluoroethylene); polyesters (examples include, but are not limited, polycarbonate and polybutylene terephthalate); or may comprise at least one polymer selected from any combination thereof.If two or more of the above-mentioned polymers are present, they may be combined to form a polymer blend (i.e., at least two different homopolymer chains melt and mix together without covalent bonding), a copolymer (i.e., two or more different monomers covalently bonded within the same polymer chain), or any other suitable form known to those skilled in the art.

[0100] As used herein, the term "ionomer" is intended to have its usual meaning in the art and refers to a synthetic polymer electrolyte comprising both electrically neutral and ionized groups along a polymer backbone. The electrically neutral and ionized groups may be regularly or randomly distributed. The term "inorganic polymer" is intended to have its usual meaning in the art and refers to a polymer having an inorganic backbone composed of atoms other than carbon. As used herein, the term "polyvinyl polymer" is intended to have its usual meaning in the art and refers to a polymer obtained by polymerization from a compound containing vinyl groups.

[0101] In some preferred embodiments, the polymer may be intrinsically conductive or ionic conductive and may contain at least one of the following: polyacrylonitrile, cellulose, polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), polythiophene (PTh), polydopamine (PDA), nylon, polyaniline, triallyl isocyanurate, polypyrrole, or any combination thereof.

[0102] In certain embodiments, carbonaceous materials, metallic materials, semimetallic materials, polymers, or any combination thereof may be in the form of hollow core-shell particles, if present.

[0103] As used herein, the term “hollow core-shell particle” has its usual meaning in the art and refers to a particle comprising a shell surrounding a hollow core, which is effectively a single pore. The pore may be a void or may contain active or inactive materials such as sulfur or selenium, which may enter or exit the pore during the cycle or manufacturing process.

[0104] In a preferred embodiment of the electrolytic cell of the present invention, after cathode formation, sulfur and / or selenium are generally housed within the hollow core-shell particles. Thus, after cathode formation, the hollow core-shell particles may be at least partially filled with sulfur and / or selenium, or may be mostly, substantially, or completely filled; however, it is advantageous when the particles are only partially filled (e.g., in the range of 5 to 80 volume%, or about 10 to 50 volume%, or about 25 to 75 volume%, e.g., about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 volume%). This is because the inventors understand that this amount of sulfur and / or selenium reduces the mechanical stress on the shell structure as the sulfur and / or selenium expand or contract during the cycle, thereby extending the cycle life. In some embodiments, sulfur and / or selenium may optionally cover substantially all of the shell of the hollow core-shell particle, or at least partially cover the shell of the particle so that sulfur penetrates from the shell to the hollow core of the core-shell particle. As used herein, “substantially cover all of the shell of the hollow core-shell particle” is intended to mean that at least 70%, or at least 80%, or at least 90% of the shell is covered, i.e., about 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or 100%, or any range within that.

[0105] The incorporation of hollow core-shell particles containing at least one of carbonaceous materials, metallic materials, semimetallic materials, polymers, or any combination thereof allows for a mechanically stable host structure for the delithiation and lithiation (and subsequent volume expansion) of sulfur and / or selenium. Furthermore, although not bound by any theory, the inventors understand that particles having a hollow core-shell structure are generally conductive, and when combined with sulfur and / or selenium (e.g., using melt diffusion techniques), the sulfur and / or selenium can be contained within the core of the particle and remain there during the cycle. Thus, a high utilization rate of sulfur and / or selenium is expected, which, advantageously, leads to higher charge / discharge capacity.

[0106] In some embodiments, the hollow core-shell particles have an average particle diameter in the range of 0.1 nm to 40 nm, or 0.5 nm to 35 nm, or 1 nm to 30 nm, or 4 nm to 20 nm, or 3 nm to 15 nm, for example, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 nm. The average particle diameter in this range is expected to have high interfacial contact between sulfur and core-shell particles, which will enable electrochemical cells with high sulfur utilization. Particle size can be determined using any known appropriate analytical technique such as dynamic image analysis (DIA), static laser light scattering, dynamic light scattering (DLS), sieving analysis, or by visual analysis of transmission electron microscope (TEM) or scanning electron microscope (SEM) images.

[0107] If present, the hollow core-shell particles may have any preferred geometry. These may have one of a wide range of geometry, including, but not limited to, spherical, cubic, quadrangular prism, pentagon, hexagon, heptagon, or octagon. The geometry is often mathematically imperfect and may be "substantially" a given geometry. As used herein, the term "substantially" with respect to these geometry can be interpreted to mean that it is clearly recognizable as a given geometry (e.g., spherical), but does not mathematically have that shape (e.g., not a perfect sphere). This may include those that extend along one axis by perhaps ±20% or ±10% (in some cases in the range of 20% or 10% to 1%). The presence of surface roughness is probably surface protrusions or depressions of about ±10% (in some cases 10% to 1%) of the shell thickness.

[0108] In certain embodiments, the hollow core-shell particles may be substantially spherical. Spherical hollow core-shell particles have a high surface area, which results in a high sulfur load and, therefore, a high sulfur utilization rate.

[0109] Hollow core-shell particles generally form a complete shell surface. However, in some cases, at least a portion of the particle is partially formed, resulting in the presence of holes that exist in the form of missing one or more faces (or partial faces) of the shell surface. In such embodiments, at least about 75% of the hollow core-shell particle, or at least 80%, or at least 85%, or at least 90%, so that the upper limit is 100%, 99.9%, or possibly 99%, form a complete shell surface, and may be, for example, about 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or 100% complete. It is understood that if at least 75% of hollow core-shell particles form a complete shell surface, the particles will be more robust to cycles and more resistant to degradation during battery operation.

[0110] If present, hollow core-shell particles may have a unimodal, bimodal, or multimodal particle size distribution. In most cases, hollow core-shell particles have a unimodal particle size distribution.

[0111] If present, hollow core-shell particles are in the range of approximately 0.01 to 50 nm, or approximately 0.1 nm to 40 nm, or approximately 0.5 to 30 nm, or approximately 1 to 25 nm, for example, approximately 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9 The shell thickness may be 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 nm. The inventors understand that this range allows for improved structural rigidity and elasticity of the particles in some embodiments, and as a result, better resistance to cell expansion.

[0112] The shell of a hollow core-shell particle may be porous, or partially porous, in addition to having holes as described above, or instead. As used herein, the term “porous” is given its common meaning in the art and refers to the presence of one or more pores, often many pores, within the shell. Each pore typically has a cross-section in the range of 0.1–3.0 nm, or in the range of 0.3–2.0 nm, or may be about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 nm, or any range therein.

[0113] As described above, the hollow core-shell particles may include carbonaceous materials, metallic materials, metalloids, polymers, or combinations thereof. Therefore, all four components, three, two, or just one of the components may be present.

[0114] In some embodiments, the cathode may include carbon-sulfur composites, metal sulfides, polymer-sulfur composites, carbon-selenium composites, carbon-sulfur-selenium composites, polymer-selenium composites, metalloid sulfides, or combinations thereof.

[0115] In certain embodiments, the carbon-sulfur composite and / or carbon-selenium composite includes a carbonaceous material selected from at least one of graphene, reduced graphene oxide, carbon nanofibers, carbon nanotubes (CNTs), multiwall carbon nanotubes (MWCNTs), microporous carbon, mesoporous carbon, carbon black (e.g., acetylene black, channel black, furnace black, lamp black, and thermal black), and activated carbon. The carbonaceous material may be in the form of hollow core-shell particles (e.g., hollow core-shell carbon black particles). Carbonaceous hollow core-shell particles have very high conductivity, resulting in high charge / discharge capacity.

[0116] Examples of carbon-sulfur composites include, but are not limited to, sulfur-graphene, sulfur-reduced graphene oxide, sulfur-carbon nanofibers, sulfur-CNTs, sulfur-MWCNTs, sulfur-microporous / mesoporous carbon (e.g., S-CNovel), and sulfur-Black Pearls 2000®. Examples of carbon-selenium composites include, but are not limited to, selenium-graphene, selenium-reduced graphene oxide, selenium-carbon nanofibers, selenium-CNTs, selenium-MWCNTs, selenium-microporous / mesoporous carbon (e.g., S-CNovel), or combinations thereof. Examples of carbon-sulfur-selenium composites include, but are not limited to, carbon black-sulfur-selenium composites. Specific examples of carbon black may include, but are not limited to, CNovel® and MSC-30.

[0117] Examples of polymer-sulfur composites include, but are not limited to, sulfur-nylon, sulfur-polyaniline, sulfur-triallyl isocyanurate, sulfur-polypyrrole, or combinations thereof.

[0118] In some embodiments, the cathode may include a metal sulfide, a metal selenide, a metal sulfoselenide, a metalloid sulfide, or a combination thereof.

[0119] In some embodiments, the cathode comprises a metal sulfide. Optionally, the metal sulfide has a one-dimensional structure, including, but not limited to, nanotubes, wires, and rods. Such structures allow for a high metal / sulfur interface, thereby increasing the reaction rate. In addition, the use of a one-dimensional structure provides a cathode with good structural stability. Furthermore, although not constrained by theory, the use of a one-dimensional structure is thought to allow for a higher sulfur load, resulting in a cell with both high mass energy density and volume energy density.

[0120] In other embodiments, the metal sulfides have a two-dimensional layered structure. Two-dimensional layered structures, such as two-dimensional nanosheets, overlap and stack on top of each other to form a network structure. Although not bound by theory, these structures have a large metal / sulfur interface that can effectively capture the formed polysulfides and hold them in place through chemical bonds. A high metal / sulfur interface also generally leads to faster reaction rates.

[0121] In addition, although not bound by theory, the layered structure adapts to the volume expansion of sulfur and lithium ions (Li + ) and / or sodium ions (Na + It is thought that this can conduct electricity. Furthermore, by peeling off the layered structure, smaller particles can be obtained, which can improve the electrochemical performance of the battery.

[0122] In some other embodiments, the metal sulfide may have a three-dimensional structure including, but not limited to, metal sulfide nanoparticles such as core-shell metal sulfide and flower-shaped metal sulfide nanomaterials. As those skilled in the art will understand, the three-dimensional structure can withstand the volume expansion of sulfur and / or selenium. Although not bound by theory, polysulfides can be retained within the three-dimensional structure. Thus, the use of a three-dimensional structure provides a cathode with an optimized reaction rate. In addition, the three-dimensional structure can have a higher sulfur load compared to a one-dimensional or two-dimensional structure, thereby providing a higher mass energy density and volume energy density to the cell.

[0123] The metal sulfide may contain one or more metals, so that a single metal sulfide may be used, or a mixed metal sulfide containing two or more metals (bimetallic, trimetallic, or multimetallic systems) may be used.

[0124] If a single metal sulfide exists, its structural formula is M x S yThe elements may include, where M is a metal, 1 ≤ x ≤ 3, and 1 ≤ y ≤ 4. The metal may be a transition metal, an alkaline earth metal, an alkali metal, or a poor metal (i.e., a metal found in groups 13-16 of the periodic table). Optionally, the metal may be selected from molybdenum (Mo), tin (Sn), titanium (Ti), vanadium (V), tungsten (W), tantalum (Ta), hafnium (Hf), or rhenium (Re), or sometimes a combination thereof.

[0125] Single metal sulfides include α-manganese sulfide (α-MnS), β-manganese sulfide (β-MnS), γ-manganese sulfide (γ-MnS), iron sulfide (FeS, Fe3S4), iron disulfide (FeS2), cobalt sulfide (CoS, CoS2, Co3S4, and Co9S8), zinc sulfide (ZnS), copper sulfide (CuS), bismuth(III) sulfide (Bi2S3), germanium sulfide (GeS), germanium disulfide (GeS2), lithium sulfide (Li2S), calcium sulfide (CaS), tin(II) sulfide (SnS), and tin(IV) sulfide. (SnS2), antimony trisulfide (Sb2S3), indium sulfide (In2S3), α-indium sulfide (α-In2S3), β-indium sulfide (β-In2S3), γ-indium sulfide (γ-In2S3), zirconium sulfide (ZrS), cerium sulfide (Ce2S3), molybdenum disulfide (MoS2), molybdenum trisulfide (MoS3), silver sulfide (Ag2S), cadmium sulfide (CdS), tungsten disulfide (WS2), nickel sulfide (NiS), vanadium sulfide (VS2), titanium sulfide (TiS2, Ti 0.67S), lead sulfide (PbS), niobium sulfide (NbS), niobium disulfide (NbS2), tantalum disulfide (TaS2), tellurium disulfide (TeS2), rhodium(III) sulfide (Rh2S3), palladium sulfide (PdS), palladium disulfide (PdS2), rhenium disulfide (ReS2), osmium sulfide (Os2S3), platinum sulfide (PtS), iridium disulfide (IrS2), iridium(III) sulfide The following may be selected: (II)(Ir2S3), chromium sulfide (CrS), chromium sulfide (III)(Cr2S3), barium sulfide (BaS), strontium sulfide (SrS), cesium sulfide (Cs2S), rubidium sulfide (Rb2S), thallium sulfide (I)(Tl2S), beryllium sulfide (BeS), ytterbium sulfide (YbS), hafnium sulfide (HfS2), or combinations thereof. The term "copper sulfide" is defined as the formula Cu x S y This includes chemical compounds and minerals having , where it should be noted that 0.5 ≤ Cu ≥ 2 and 0.5 ≤ S ≥ 2. For example, the term copper sulfide is Cu 1.12 S, Cu 1.39 S, Cu 1.6 S, Cu 1.75 S, Cu 1.8 S, Cu 1.8 S, or Cu 1.96 It may contain S. The term "nickel sulfide" is used for NiS2, Ni 3+x Please note that this includes S2, Ni3S2, Ni6S5, Ni7S6, Ni9S8, and Ni3S4.

[0126] In some embodiments, the metal sulfide may be a mixed metal sulfide, and the metal may be selected from transition metal ions, alkaline earth metals, alkali metals, poor metals, or combinations thereof. Optionally, the mixed metal sulfide may include molybdenum (Mo), tin (Sn), titanium (Ti), vanadium (V), tungsten (W), tantalum (Ta), hafnium (Hf), or rhenium (Re), or sometimes combinations thereof. Examples of mixed metal sulfides include, but are not limited to, Zn. 1-x Cu x S, Cu3SbS4, Fe 4.60 Ni 4.55S8、PbMoS2、Li5A1S4、KCrS2、Cu6WSnS8、Zn 1-x Cu x S, CuSbS2, Fe 5.80 Ni 3.98 S8、CdMoS2、Li2FeS2、KCr5S8、Cu6GeWS8、Zn 1-x Fe x S、Cu5FeS6、FeMoS2、NbMoS2、Li4GeS4、CsTaS3、(CuGa) 0.8 Zn 0.4 S2、Zn 1-x In x S、Cu 12 Sb4S 13 、CoMoS2、CoNi2S4、LiGaS2、Cs2Co3S4、Pb4FeSb6S 14 Zn 1-x Mn x S、Cu2Sb8S 13 、CoMoS4、FeNi2S4、γ-Li3PS4、K2Ni3S4、Pb4MnSb6S 14 Zn 1-x Co x S、Cu2GeS3、Co 0.5 MoS2、ZnCo2S4、LiInS2、Rb2Ni3S4、Ag4MnSb2S6、Zn 1-x Ce x S、CuGaS、Co 1-x Ru x S2、Ni 0.33 Co 0.67 S2, RbCr5S8, Cs2Ni3S4, Ag(Fe,Ni)8S8, ZnY2S4, CuGaS2, Co 1-x Rh x S2、Sb 2-x Bi x S3、C S Cr5S8、RbCu4S3、Ag2MnSnS4、Cd 1-x Zn x S、Cu2WS4、NiMoS2、NiMoS2、Ni 0.5 MoS2, Rb2Pt3S4, Bi 0.94 Sb 1.06 S3, Ni(Bi,Pb)2S2, Cd 1-x Mn x S, Cu3TaS4, MgMoS2, Rh1-x Ru X S2、CS2Pt3S4、NiCoMoS、(CuIn) x Zn 2(1-x) S2、Sn 1-x Bride x S、Cu 1-x Ti2S4、PdMoS2、CoNi2S4、K2Pt4S6、Cu2ZnSnS4、Cu(In,Ga)(Se,S)2、MnCr2S4、Cu 0.89 Ti2S4、W 1-x Bride x S2、SnCoS4、Co 0.4 Ru 0.6 S2、Cu2FeSns4、(Cu,Fe)(Re,Mo)4S8、CdCr2S4、Cu 0.32 TiS2、VMo2S4、AgInS4、No 0.6 Ru 0.4 S2、Cu2ZnGeS4、Cu 10 Fe3MoGe3S 16 、CdIn2S4、Cu 0.92 Ti2S4、Mo 1-x W x S2、Ag3CuS2、NaInS2、CuPbSbs3、Cu 10 Fe3WGe3S 16 、[M4In 16 S 33 ] 10- (M=Mn, Co, Zn, Cd) and Cu 0.37 TiS2、NiCr2S4、AgIn5S8、CuIr2S4、Cu6SnMoS8、Ag6(Cu4Fe2)sb4S 12 、Cu3VS4、NiCo2S4、AgBiS2、Na3NbS4、Cu2Fe5Ni2S8、(Cu,Fe)(Re,Mo)4S8、CuV2S4、NiV2S4、Ag2WSS4、Na3S4、Tau 10 Cu2Sb4S 13 、Pb4Mo4VSbS 15 、CdSe x S 1-x 、Cu2MoS4、Ni6MoS4、ZnLn2S4、Rb3NaS4、Cu 12 VAs3S 16 、AgMnPb3Sb5S 12, CuCoS4, Cu3NbS4, Ni9Sn2S2, MnCo2S4, Rb3TaS4, Cu 13 VSn3S 16 ,Pb5Mn3Ag2Sb6As4S 24 CuInS2, CuCrS2, Ni 1-x Zn x S, MgIn2S4, K3NbS4, Cu 13 VGe3S 16 Cu 10 Fe3WGe3S 16 Cu 1.0 In 2.0 S 3.5 , CuFeS2, FeMo4S6, MgSc2S4, K3TaS4, CoFe(AsS)2, Cu 13 V(Sb,Sn,As)3S 16 Cu2SnS3, Fe 0.5 Co 0.5 S2, FeNi2S4, Pd 30 Cu 10 S9, KFes2, Be3Mn4(SiO4)3S, Pb4Mo4VSbS 15 ,Cu3SbS3,Fe 3.63 Ni 5.39 Examples include S8, FeV2S4, LiAlS2, NaCrS2, (Fe,Zn,Mn)S, or any combination thereof.

[0127] In other embodiments, the metal sulfide is a metal disulfide. The metal disulfide may be selected from molybdenum disulfide (MoS2), tungsten disulfide (WS2), hafnium disulfide (HfS2), tin disulfide (SnS2), titanium sulfide (TiS2), vanadium sulfide (VS2), tantalum disulfide (TaS2), rhenium disulfide (ReS2), or any combination thereof. Although not bound by theory, transition metal disulfides within the transition metal dichalcogenide family are particularly beneficial because they can be in a monolayer form where the metal atom is located between two sulfur atoms.

[0128] In some embodiments, the metal sulfide includes molybdenum disulfide. Molybdenum disulfide may be in the form of a 1T polymorph (1T-MoS2), a 2H polymorph (2H-MoS2), or a 3R polymorph (3R-MoS2). In many cases, molybdenum disulfide is in the form of a 1T polymorph. The octahedral or triangular-anti-quadrilateral prism geometry of the 1T polymorph can form strong bonds with the polysulfide, reducing the possibility of polysulfide shuffling. Furthermore, the octahedral or triangular-anti-quadrilateral prism geometry of the 1T polymorph can provide higher lithium diffusion, thereby resulting in enhanced electrochemical performance.

[0129] In certain embodiments, the metal sulfide is prelithiated. The terms “prelithiated” and “prelithiated” have their usual meanings and relate to a pretreatment step in which lithium ions or sodium ions are added to the cell before operation. Although not bound by theory, lithiating a metal sulfide may increase one or both of the electrical conductivity and / or ionic conductivity of the metal sulfide, and consequently, the cathode as well. The metal sulfide may contain molybdenum disulfide in the form of a 1T polymorph, and molybdenum disulfide may be lithiated in the form of a 1T polymorph.

[0130] In some embodiments, the metal sulfide may be in granular form. The particles may be in the range of 1 μm to 20 μm, or 1 μm to 5 μm, or 10 to 15 μm, for example, about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 μm. Having metal sulfide particles within this size range is expected to result in a higher sulfur utilization rate, thereby improving power performance.

[0131] Particles can be obtained by any known conventional means, including, but not limited to, chemical / physical exfoliation, bead milling, jet milling, and / or ball milling. Particle size analysis can be determined using any known technique such as dynamic image analysis (DIA), static laser scattering, dynamic light scattering (DLS), sieving analysis, or by visual analysis of transmission electron microscope (TEM) or scanning electron microscope (SEM) images. It is expected that those skilled in the art can easily optimize this process.

[0132] In certain embodiments, the cathode may further contain atomic sulfur. The cathode may also contain a metal sulfide further containing sulfur. For example, the cathode may contain a metal sulfide-sulfur composite. The metal sulfide may instead contain molybdenum disulfide, or molybdenum disulfide further containing sulfur.

[0133] In embodiments in which the cathode comprises sulfur and a metal sulfide, the sulfur may be incorporated into the metal sulfide by conventional methods. For example, this can be achieved by melt injection, in which the metal sulfide is immersed in sulfur at about 150°C to 160°C. Although not bound by theory, when using the melt injection method, the molten sulfur can diffuse throughout the pores of the metal sulfide.

[0134] In such embodiments, the average pore size of the metal sulfide is in the range of 0.1 nm to 20 nm, or in the range of 1 nm to 10 nm, for example, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 nm. It is understood that pore sizes within these specific ranges allow for higher sulfur utilization. As those skilled in the art will understand, the average pore size can be measured using any known technique such as Brunauer-Emmett-Teller (BET) porosimetry or mercury porosimetry.

[0135] Metal sulfides may have a porous one-dimensional, two-dimensional, or three-dimensional structure.

[0136] In some embodiments, the metal sulfide further comprises selenium forming a metal sulfoselenide, the metal sulfoselenide having the structural formula MS 1-x Se x The compound has the following properties, where M is a metal and 0 ≤ x ≤ 1. The metal may be a transition metal ion, an alkaline earth metal, an alkali metal, or a poor metal (i.e., a metal found in groups 13-16 of the periodic table). The inventors understand that the use of metal sulfoselenides has the advantage of improving power within the cell due to the high conductivity of Se.

[0137] In some embodiments, the cathode may be in granular form. The particles may be in the range of 1 μm to 20 μm, or 1 μm to 5 μm, or 5 to 15 μm, for example, about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 μm. Having particles within this size range results in a higher utilization rate of sulfur and / or selenium, which leads to an improvement in the power performance of the cell.

[0138] Particles can be obtained by conventional means, but are not limited to chemical / physical exfoliation, bead milling, jet milling, and / or ball milling. Particle size analysis can be determined using any known technique such as dynamic image analysis (DIA), static laser scattering, dynamic light scattering (DLS), sieving analysis, or by visual analysis of transmission electron microscope (TEM) or scanning electron microscope (SEM) images.

[0139] In some embodiments, the cathode further comprises a current collector. The current collector may comprise any suitable material such as aluminum, carbon, copper, titanium, or stainless steel. The current collector may comprise a metal foil such as aluminum foil, copper foil, titanium foil, or stainless steel foil. In preferred embodiments, the current collector comprises aluminum foil. The current collector may be further coated with a protective layer. If present, the protective layer may be a carbon-based layer, and as a result, the current collector is a carbon-coated current collector. In embodiments in which the current collector comprises aluminum (e.g., aluminum foil), copper (e.g., copper foil), titanium (e.g., titanium foil), or stainless steel (e.g., stainless steel foil), the current collector may be further carbon-coated. In other embodiments, the current collector may comprise carbon-coated aluminum foil. The inventors understand that carbon coating may improve the corrosion resistance and adhesion of the current collector to the cathode material.

[0140] In some embodiments, the cathode may have a thickness in the range of about 20 μm to about 300 μm, or in the range of about 50 μm to about 200 μm, or in the range of about 75 μm to about 150 μm, for example, or about 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, or 300 μm. The cathode may be single or double-sided, and the dimensions herein are cited without a current collector, but those skilled in the art can easily make the necessary modifications as needed.

[0141] In some embodiments, the cathode may further contain a binder. While not constrained by theory, the binder may act to bond the cathode components together. In addition, or alternatively, the binder may also help to bond the cathode components to the current collector. In doing so, the binder can provide a cathode with enhanced mechanical rigidity and improve the processability of the cathode.

[0142] If present, the binder may be guar gum, xanthan gum, gum arabic, a polymer binder, or any combination thereof. Preferably, the binder may be guar gum, xanthan gum, or a combination thereof.

[0143] If the binder is a polymer binder, it may be, for example, polyether, such as poly(ethylene oxide), polyethylene glycol, polypropylene glycol, polytetramethylene glycol (PTMG), polytetramethylene ether glycol (PTMEG), polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), sulfonated tetrafluoroethylene-based fluoropolymer copolymer, carboxymethylcellulose (CMC), styrene butadiene (SBR), polypyrrole, polythiophene, polyaniline, polyvinyl alcohol, poly(ethylene)imine, polyacetylene, polyphenylenevinylene, poly(3,4-ethylenedioxythiophene), polyphenylene sulfide, gelatin, or any mixture or combination thereof.

[0144] In some embodiments, the binder may be selected from halogenated polymers, for example, the binder may be selected from fluorinated polymers. Examples of suitable binders include, but are not limited to, poly(vinylidene fluoride) (PVDF), often in the form of poly(trifluoroethylene) (PVF3); polytetrafluoroethylene (PTFE); copolymers of vinylidene fluoride with hexafluoropropylene (HFP) or trifluoroethylene (VF3) or tetrafluoroethylene (TFE) or chlorotrifluoroethylene (CTFE); fluoroethylene / propylene (FEP) copolymers; copolymers of ethylene with fluoroethylene / propylene (FEP) or tetrafluoroethylene (TFE) or chlorotrifluoroethylene (CTFE); perfluoropropyl vinyl ether (PPVE); perfluoroethyl vinyl ether (PEVE); and copolymers of ethylene with perfluoromethyl vinyl ether (PMVE); or blends or mixtures thereof.

[0145] Other examples of suitable binders include, for example, polyacrylonitrile, polyurethane, PVDF-acrylic copolymer; polyacrylic acid, polyimide, and polyvinyl alcohol. Further preferred binders include rubber (e.g., styrene-butadiene rubber), cellulosic binders (e.g., carboxymethylcellulose), or gelatin.

[0146] If present, the cathode may contain a binder in an amount of 0.05 to 20% by weight based on the total weight of the cathode, or 0.5 to 10% by weight based on the total weight of the cathode, for example, 1 to 5% by weight, for example, about 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20% by weight, for example, 2 to 3% by weight.

[0147] In certain embodiments, the cathode may further include an ion-conducting material. The ion-conducting material has a temperature of 10°C at 25°C.-7 Bulk ion conductivity exceeding S / cm, for example, 10 -6 It may have a bulk ion conductivity exceeding S / cm. The cathode may be Li3PS4 or Li x P y S z If the material contains electroactive ion-conducting materials such as those mentioned above, further ion-conducting materials may not be necessary.

[0148] If present, the ion-conducting material is selected from ion-conducting ceramic materials, ion-conducting polymers, or a combination thereof. The presence of the ion-conducting material allows for an increase in lithium cation conductivity within the cell, thereby resulting in improved power performance.

[0149] The ceramic material may have a crystalline, polycrystalline, partially crystalline, or amorphous structure. Suitable ceramic materials include, but are not limited to, oxides, carbonates, nitrides, carbides, sulfides, oxysulfides, and / or oxynitrides of metals and / or metalloids. If the anode contains lithium, a lithium alloy, or silicon, the ceramic material may contain lithium; similarly, if the anode contains sodium or a sodium alloy, the ceramic material may contain sodium. A non-limiting example of a suitable ceramic material having sufficient ionic conductivity for use in lithium-based or silicon-based systems may be produced by various combinations of lithium compounds, for example, lithium-containing ceramic materials include lithium oxide (Li2O, LiO, LiO2, LiRO2, where R is scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and / or lutetium), lithium carbonate (Li2CO3), lithium nitride (e.g., Li3N), lithium oxysulfide, lithium oxynitrogen, and lithium garnet-type oxide (e.g., Li7La3Zr2O) 12 )), Li 10 GeP2S 12Examples include lithium phosphorus oxynitride, lithium silicon sulfide, lithium germanoloxide, lithium lanthanum oxide, lithium titanium oxide, lithium borosulfide, lithium aluminosulfide, lithium phosphorus sulfide, lithium silicate, lithium borate, lithium aluminate, lithium phosphate, lithium halides, and combinations thereof. In certain cases, the ceramic material includes lithium oxide, lithium nitride, or lithium oxysulfide. In some cases, the ceramic includes carbonate and / or carbides.

[0150] Examples of ceramic materials that can be used as lithium-ion-containing conductive materials include algyrodite (i.e., Li 7-p BS 6-p X p (where B is phosphorus or arsenic, X is chlorine, bromine or iodine, and p is 0-1), Li-containing oxides, for example, Li 3.3 La 0.56 TiO3; LiTi(PO4)3 and other NASICON structures; LiSICON(Li 14 Zn(GeO4)4); Li 10 GeP2S 12 Garnet: Li7La3Zr2O 12 Examples include: Li2O; other oxides such as Al2O3, TiO2, ZrO2, SiO2, and ZnO; sulfides such as LiS-P2S5; antiperovskites such as Li3OCl; hydrides such as LiBH4, LiBH4-LiX (where X=Cl, Br, or I), LiNH, LiNH2, LiAlH6, and Li2NH; borides or phosphates such as Li2B4O7, Li3PO4, and LiPON; carbides or hydroxides such as Li2CO3 and LiOH; fluorides such as LiF; nitrides such as Li3N; sulfides such as lithium borosulfide; lithium phosphorusulfide, lithium aluminosulfide, oxysulfides, and praseodymium oxide. At least one of the above ceramic materials, or a combination thereof, may be used. As stated above, if the anode contains sodium metal or sodium alloy, the sodium ion equivalent of any of these conductive materials may be utilized.

[0151] In a preferred embodiment, the argyrodite has the chemical formula Li6PS5Cl.

[0152] In some embodiments, the ion-conducting material may be formed from an intrinsically ion-conductive polymer material such as a sulfonated tetrafluoroethylene-based fluoropolymer copolymer (Nafion®). Alternatively, 10 -7 Polymers blended with lithium (or sodium) salts that can achieve bulk conductivity exceeding S / cm may also be used. Examples of suitable polymers include, but are not limited to, ethylene oxide (EO) polymers (e.g., PEO); acrylate polymers (e.g., PMMA); polyamines (polyethyleneimine); siloxanes (poly(dimethylsiloxane)); polyheteroaromatic compounds (e.g., polybenzimidazole); polyamides (e.g., nylon); polyimides (e.g., Kapton®); polyvinyls (e.g., polyacrylamide, poly(2-vinylpyridine), poly(N-vinylpyrrolidone), poly(methylcyanoacrylate), poly(vinyl acetate), poly(vinyl alcohol), poly(vinyl chloride), poly(vinyl fluoride)); inorganic polymers (e.g., polysilane, polysilazane, polyphosphazene, polyphosphonate); polyurethanes; polyolefins (e.g., polypropylene, polytetrafluoroethylene); and polyesters (e.g., polycarbonate, polybutylene terephthalate). Optionally, coblock polymers such as sulfonated tetrafluoroethylene-based fluoropolymer copolymers (e.g., Nafion®) may be used. At least one of the polymer materials described above, or a combination thereof, may be used. In some embodiments, the cathode contains ceramic particles combined with one or more ion-conducting polymers.

[0153] In certain embodiments, the conductive ceramic material is argyrodite, lithium lanthanum zirconium oxide (Li7La3Zr2O 12 )(LLZO), Lithium aluminum titanium phosphate (Li 1.3 Al0.3 Ti 1.7 (PO4)3)(LATP), Lithium germanium phosphide (Li 10 GeP2S 12 The ion-conducting polymer may be selected from at least one of (LGPS), lithium phosphate pentasulfide (Li2S-P2S5), or a combination thereof, and the ion-conducting polymer may be selected from at least one of polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylenevinylene, and poly(3,4-ethylenedioxythiophene), or any combination thereof.

[0154] In some embodiments, the cathode may contain 1 to 60% by weight of an ion-conducting material, based on the total weight of the cathode.

[0155] In some embodiments, the cathode may further include a conductive carbon material. The conductive carbon material may be selected from carbon nanotubes, carbon nanofibers, graphene, graphene oxide, graphite, carbon black (e.g., Carbon Black Super-P®, KETJENBLACK®), activated carbon (e.g., Maxsorb III®), microporous carbon, mesoporous carbon, macroporous carbon, or any combination thereof.

[0156] The conductive carbon material may be present in amounts ranging from 0.1 to 30% by weight, or 1 to 20% by weight, or 5 to 15% by weight of the total weight of the cathode, for example, in the range of approximately 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20% by weight. The inclusion of the conductive carbon material is expected to result in an increase in conductivity within the cathode. In addition, the inclusion of the conductive carbon material may add some porosity to the cathode, enabling better electrolyte penetration, which contributes to shortening the lithium ion migration pathway within the cathode. As a result, the power performance of the cell may be improved.

[0157] Conductive carbon materials may include microporous carbon, mesoporous carbon, macroporous carbon, or any combination thereof. Microporous carbon, mesoporous carbon, macroporous carbon, or combinations thereof may have a disordered or regular network structure and may be selected from the group consisting of carbon molecular sieves, activated carbon; carbon black, e.g., Super P carbon black (SPCB); or combinations thereof. Mesoporous materials may be prepared using a regular mesoporous silicon or magnesium oxide skeleton.

[0158] If present, the pore size of the mesoporous carbon material may be in the range of approximately 5 nm to approximately 40 nm, or approximately 10 nm to approximately 30 nm, or approximately 15 nm to approximately 25 nm, for example, approximately 5, 10, 15, 20, 25, 30, 35 or 40 nm, or any range within that range. If present, the pore size of macroporous carbon materials may be in the range of approximately 60 nm to approximately 500 nm, or approximately 100 nm to approximately 300 nm, for example, approximately 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 420, 440, 460, 480, or 500 nm, or any range within that range. Mesoporous and / or macroporous carbon having pore sizes within these ranges provides effective mass transport of electrolytes while providing a cathode strong enough to withstand external pressure when the cell is in use.

[0159] If present, mesoporous and / or macroporous carbon material is present in amounts ranging from about 0.1% to about 10% by weight, or about 0.3% to about 7% by weight, or about 0.5% to about 5% by weight, based on the total weight of the cathode, for example, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10% by weight, or any range within that range. If a current collector is present, the total weight of the cathode excludes the weight of the current collector. The presence of the above amounts of mesoporous and / or macroporous carbon material provides a balance between optimal porosity to enable effective mass transport of the electrolyte and structural integrity of the cathode.

[0160] The presence of mesoporous and / or macroporous carbon material in the cathode provides several pathways for the liquid or gel electrolyte, thereby enabling effective mass transport and good power capacity. Although not bound by theory, since the pores of mesoporous and / or macroporous carbon material are distinct components of the cathode relative to components (i) and (ii) detailed above, the pores of mesoporous and / or macroporous carbon material are empty, which means that sulfur and / or selenium from (i) are not present in any of the pores of the mesoporous and / or macroporous carbon material, thereby providing voids for the liquid electrolyte to be filled when the cell is assembled. As a result, the cell facilitates the movement / diffusion of lithium / sodium cations throughout the cathode. Thus, mesoporous and / or macroporous carbon material adds some degree of porosity to the cathode, enabling better electrolyte penetration, which contributes to shortening the lithium ion / sodium ion movement pathway within the cathode. However, this must be balanced by the need to keep the load of the liquid or gel electrolyte to a minimum, or to a "low" or "dilute" level, thereby providing advantages to the present invention. Furthermore, mesoporous and / or macroporous carbon materials result in increased conductivity within the cathode.

[0161] In some embodiments, the cathode is prelithiated or presozioated. Prelithiated or presozioated cathodes result in an increase in the energy density of the cell.

[0162] In certain embodiments, the cathode is calendered. While not bound by theory, calendering may reduce the porosity of the cathode, which may allow for a lower electrolyte load and result in an increase in volumetric energy density (Wh / L). As used herein, the term “volumetric energy” refers to the amount of energy stored in a cell per unit volume in liters. Furthermore, calendering may also result in smoothing and leveling of the cathode, which can help extend the life of the cell without affecting the cell's utilization rate.

[0163] Generation method A second aspect of the present invention provides a method for generating an electrolyte system as defined in the first aspect of the present invention. This method is (i) A step of generating a paste from a first electrolyte material, (ii) The step of calendering the paste to form a solid electrolyte, (iii) Providing a second electrolyte comprising a liquid electrolyte, a gel electrolyte, or a combination thereof, wherein the second electrolyte has sufficient polysulfide and / or polyselenide solubility to prevent shuttling.

[0164] The first electrolyte and the second electrolyte are the same as the first electrolyte and the second electrolyte described above with respect to the first aspect of the present invention.

[0165] As used herein, the term "calendering" refers to a compression process. Calendering can be performed through conventional methods, such as the use of calendering rollers.

[0166] In some embodiments, producing a paste may involve combining a first electrolyte with a solvent, binder, or a combination thereof. The solvent may be polar, nonpolar, or a combination thereof. Preferred polar solvents may be selected from water, dimethyl sulfoxide (DMSO), tetrahydrofuran, acetone, ethyl acetate, dimethylformamide, dichloromethane, ethanol, methanol, isopropyl alcohol, or a combination thereof. Preferred nonpolar solvents may be selected from pentane, hexane, diethyl ether, toluene, xylene, benzene, or a combination thereof. In preferred embodiments, the nonpolar solvent is toluene, xylene, benzene, or a combination thereof. The solvent may be selected from water, dimethyl sulfoxide (DMSO), tetrahydrofuran, acetone, ethyl acetate, dimethylformamide, dichloromethane, ethanol, methanol, isopropyl alcohol, pentane, hexane, diethyl ether, toluene, xylene, benzene, or a combination thereof.

[0167] If the first electrolyte contains an argyrodite as described herein, the solvent may be nonpolar. Suitable or preferred nonpolar solvents are toluene, xylene, or benzene.

[0168] If present, the binder is as defined above. In some embodiments, the binder may include copolymers having repeating units containing carboxylic acid groups or conjugate bases. In other embodiments, the binder may include poly(ethylene-co-acrylic acid), carboxylated polystyrene, poly(ethylene-co-methacrylic acid), carboxylated rubber (e.g., carboxylated nitrile butadiene rubber or carboxylated styrene butadiene rubber), or any combination thereof.

[0169] In some embodiments, the solid electrolyte may contain two or more binders. For example, the solid electrolyte may contain two or more binders, three or more binders, four or more binders, or five or more binders.

[0170] The inventors understand that the presence of at least one binder improves the elasticity of the first electrolyte and therefore improves its processability. In addition, the presence of at least one binder also helps to keep the layers intact when the cell is assembled and during operation.

[0171] When calendering is performed via calender rollers, in most embodiments the first electrolyte may pass through the rollers up to five times, or once or twice. The rollers may be made of any suitable material, e.g., steel, glass, or ceramic. A force of 0kN to 100kN, often 0 to 80kN, e.g., 20 to 80kN, may be applied to the rollers. Calendering may be performed at room temperature (i.e., in the range of 15 to 25°C). Optionally, heating may be applied to the rollers. The temperature of the rollers may be in the range of 15 to 300°C. During calendering or pressing, the thickness of the cathode decreases. The thickness of the first electrolyte after calendering or pressing may be 1 to 50 μm, or about 10 to about 40 μm, or about 15 to about 30 μm. Calendering may result in smoothing and leveling of the first electrolyte, which can help extend the life of the cell.

[0172] The solid electrolyte may be in the form of a sheet after step (ii).

[0173] In some preferred embodiments, the thickness of the first electrolyte is in the range of about 5 μm to about 100 μm, or about 10 μm to about 80 μm, or about 15 μm to about 70 μm, or about 20 μm to about 60 μm, or about 30 μm to about 50 μm. The inventors anticipate that solid electrolyte thicknesses within these ranges will provide a lighter electrochemical cell without compromising cyclability and cell safety.

[0174] In some embodiments, the method includes an additional step of drying the solid electrolyte after calendering the paste. Drying may be carried out using any known technique, such as oven drying.

[0175] In some embodiments, the method includes the step of cutting a first electrolyte into a desired footprint. The cutting step may be performed using any known technique in the art, such as laser cutting or die cutting.

[0176] A third aspect of the present invention provides a method for generating an electrochemical cell according to the first aspect of the present invention. This method is (i) The steps of forming a cathode from a cathode material and cutting the cathode into a desired shape, (ii) The step of forming a first electrolyte, (iii) The step of connecting the surface of the first electrolyte to the surface of the anode, (iv) the step of providing a second electrolyte.

[0177] The first electrolyte and the second electrolyte are the same as the first electrolyte and the second electrolyte described above with respect to the first aspect of the present invention.

[0178] In some embodiments, step (i) includes mixing the cathode material with a solvent to produce a slurry, and removing the solvent to produce a cathode before cutting.

[0179] The solvent according to a third aspect of the present invention may be selected from water or a suitable organic solvent, such as N-methyl-2-pyrrolidone (NMP) or other solvents discussed herein.

[0180] The current collector may include aluminum, carbon, copper, titanium, or stainless steel. In preferred embodiments, the current collector may include aluminum, copper, titanium, or stainless steel. In some embodiments, the current collector includes a metal foil such as aluminum foil, copper foil, titanium foil, or stainless steel foil. In preferred embodiments, the current collector includes aluminum foil. The current collector may be further coated with a protective layer. Typically, the protective layer is a carbon-based layer, resulting in a carbon-coated current collector. When the current collector includes aluminum (e.g., aluminum foil), copper (e.g., copper foil), titanium (e.g., titanium foil), or stainless steel (e.g., stainless steel foil), the current collector may be carbon-coated. In certain embodiments, the current collector may include carbon-coated aluminum foil. It is understood that carbon coating improves the corrosion resistance and adhesion to the cathode material of the current collector.

[0181] In some embodiments, the second electrolyte may be held within an inert separator positioned between the cathode and the first electrolyte. The separator may be formed from a wide variety of materials. Examples of materials used for the separator include, but are not limited to, polyolefin materials such as polyethylene, polypropylene, and combinations thereof. In some embodiments, the second electrolyte is at least partially absorbed into the separator.

[0182] The method may further include connecting an additional first electrolyte to the opposing surface of the anode, so that the anode is positioned between two separate first electrolytes. In such embodiments, at least a portion of the surface of the anode is in direct contact with the respective surfaces of the two separate first electrolytes.

[0183] In embodiments of the present invention, the electrolytic cell is a pouch cell, a rectangular prism cell, or a cylindrical cell. Preferably, the cell is a pouch cell. If the cell is a pouch cell, the method may include an additional step of stacking the cathode, the first electrolyte, and the anode generated in steps (i) to (iii) before providing the second electrolyte, and a final step of sealing the pouch cell.

[0184] In some embodiments, the method according to a third aspect of the present invention further includes a step of calendering or pressing the cathode before cutting. As stated above, the term “calendering” refers to a compression process. Calendering can be carried out via conventional methods such as the use of calender rollers. When calendering is carried out via calender rollers, the cathode may pass through the rollers up to five times, or preferably once or twice. The rollers may be made of any suitable material, e.g., steel, glass, or ceramic. A force of 0kN to 100kN, often 0 to 80kN, often 20 to 80kN, may be applied to the rollers. Calendering may be carried out at room temperature (i.e., in the range of 15 to 25°C). Optionally, heating may be applied to the rollers. The temperature of the rollers may be in the range of 15 to 80°C. During calendering or pressing, the thickness of the cathode decreases. The thickness of the cathode after calendering or pressing may be 1 to 50 μm, often 10 to 40 μm, often 15 to 30 μm. Calendering may reduce the porosity of the cathode, which allows for a lower electrolyte load and results in an increase in volumetric energy density (Wh / L). As used herein, the term “volumetric energy” refers to the amount of energy stored in a cell per unit volume in liters. Furthermore, calendering may also result in smoothing and leveling of the cathode, which can help extend the lifespan of the cell without affecting its utilization rate.

[0185] battery According to a fourth aspect of the present invention, an electrochemical cell assembly is provided, comprising at least one electrochemical cell according to a first aspect of the present invention and means for applying pressure to the at least one electrochemical cell.

[0186] As those skilled in the art will understand, during cell cycling, there is expansion of sulfur and / or selenium, which causes the cathode to expand. The application of pressure helps to maintain the integrity of the cathode structure, which can be altered due to the volume expansion of sulfur and / or selenium within the cathode. In addition, the application of pressure helps to maintain good physical contact between the anode and the first electrolyte. As a result, the application of pressure is considered to help extend the cell life and improve cycle performance.

[0187] In such embodiments, the means for providing pressure includes at least one of a band, wrap, or tube positioned outside the cell assembly. The band, wrap, or tube positioned outside the cell assembly allows for the application of a stable contraction force during the cycle. As used herein, outside the cell refers to the surface of the anode. Pressure may be applied over the entire surface of the anode or substantially over the entire surface of the anode. Alternatively, force may be applied over a portion of the surface of the anode, for example, over at least 20% of the surface of the anode, or pressure may be applied over at least 40%, or at least 60%, or at least 80% of the surface of the anode.

[0188] The cell assembly may include one or more plates located on the outside of the cell. If one or more plates are present, pressure may be applied to one or more of the plates.

[0189] The cell assembly may be located inside the housing. When the cell is located inside the housing, pressure may be applied to the housing.

[0190] Band wraps or tubes can be made from any suitable material, such as elastic material or shrink wrap material. Examples of suitable elastic material include, but are not limited to, natural or synthetic rubber materials. Examples of shrink wrap material include, but are not limited to, polyvinyl chloride (PVC), polyethylene (PE), and polyolefin (POF).

[0191] Pressure may be continuously applied to one or more cells within a cell assembly, or the pressure may change over time. Other means of applying pressure may include the use of screws or weights. Those skilled in the art can assume that the method of applying pressure to the cells can be optimized.

[0192] definition Unless otherwise specified, each of the components described may be used in combination with any other components as understood by those skilled in the art. Furthermore, it is specifically assumed that all aspects of the present invention preferably "include" the features described in relation to that aspect, but may also "consist of" or "essentially consist of" those features outlined in the claims. In addition, unless specifically defined herein, all terms are intended to have their generally understood meanings in the art.

[0193] Furthermore, in the discussion of the present invention, unless otherwise stated, the disclosure of alternative values ​​for the upper or lower limits of the allowable range of a parameter should be interpreted as an implicit statement that each intermediate value of the parameter between the smaller and larger values ​​of that alternative value is also disclosed as a possible value of the parameter.

[0194] Furthermore, unless explicitly stated to be contradictory, "or" refers to an inclusive or not an exclusive or. For example, condition A or B is satisfied by one of the following: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

[0195] Furthermore, the indefinite articles "a" and "an" preceding the elements or components of the present invention are intended to be non-restrictive with respect to the number of cases (i.e., occurrences) of that element or component. Thus, "a" or "an" should be read as including one or at least one, and the singular form of an element or component also includes plural forms unless it is clearly implied that its number is singular.

[0196] Unless otherwise indicated in the operating examples or elsewhere, all numbers representing amounts of components or reaction conditions used herein should be understood to be modified in all examples by the term “approximately.” The examples are not intended to limit the scope of the invention. Wherever shown below or elsewhere, “%” means “weight percent,” “ratio” means “weight ratio,” and “parts” means “parts by weight.”

[0197] As used herein, the terms “primarily” and “substantially” shall mean “containing more than 50% by weight” unless otherwise indicated.

[0198] As used herein, weight percent refers to the weight of a particular component relative to the total weight of the reference composition.

[0199] In addition, unless otherwise stated, all numerical values ​​expressed in this application should be understood to be modified by the term “about.” Where used herein, the terms “about,” “approximately,” and “substantially” are understood to mean a range of numbers from -10% to +10%, preferably -5% to +5%, more preferably -1% to +1%, and most preferably -0.1% to +0.1%. Furthermore, where referring to a numerical range, these terms should be interpreted as supporting claims directed to any number or subset of a number within that range. For example, a disclosure of 1 to 10 should be interpreted as supporting ranges such as 1 to 8, 3 to 7, 1 to 9, 3.6 to 4.6, 3.5 to 9.9, and 8 to 10.

[0200] The complete disclosures of patents, patent documents, and publications cited herein are incorporated in their entirety by reference as if each were incorporated individually. [Examples]

[0201] The present invention will be further described with reference to the drawings and the following specific examples so that it may be more easily understood. [Brief explanation of the drawing]

[0202] [Figure 1] This is a schematic cross-sectional view of an electrochemical cell containing an electrolyte system according to one embodiment of the present invention. [Figure 2] This is a schematic diagram of a cross-section of an anode located between two separate first electrolytes according to one embodiment of the present invention. [Figure 3] The electrochemical performance data (C / 10 rate and charge-discharge voltage curve at room temperature) for the cell designed according to Example 2 are shown.

[0203] Figure 1 is a schematic cross-sectional view of an electrochemical cell 100. The electrochemical cell 100 includes a first electrolyte 110, a second electrolyte 120, an anode 105, a cathode 115, and a current collector 125. The first electrolyte 110 may be any material as considered above, the second electrolyte 120 may be any material as considered above, the anode 105 may be any material as considered above, the cathode 115 may be any material as considered above, and the current collector 125 may be any material as considered above. The first electrolyte 110 has a first surface 110a and a second opposing surface 110b. The first surface 110a is in contact with the surface of the anode 105, and the second surface 110b is in contact with the second electrolyte 120.

[0204] Figure 2 is a schematic cross-section of an anode 205 positioned between two separate first electrolytes 210(i) and 210(ii). The anode 205 can be any of the materials considered above, and the two separate first electrolytes 210(i) and 210(ii) can be any of the materials considered above. In Figure 2, the surface of the anode 205 is in direct contact with the two separate first electrolytes 210(i) and 210(ii).

[0205] Example 1 An electrochemical cell is provided.

[0206] The cathode contains 90% molybdenum sulfide / sulfur (1T-Li) as the active material. x MoS2 / S) (where 1T-Li x The MoS2:S ratio is 25:75 (i.e., 25 wt% of 1T-Li). x The cathode powder may contain MoS2 and 75% by weight of sulfur, and 10% by weight of PVDF as a binder. The cathode powder can be prepared by a simple stirring and mixing method using a 3-roll mill. The binder can be added in a second step to form a slurry, which can then be coated onto an aluminum current collector to form a cathode.

[0207] The first electrolyte may comprise 95% by weight of an argyrodite of formula Li6PS5Cl and 5% by weight of carboxylated styrene-butadiene rubber.

[0208] The first electrolyte can be prepared by mixing an argyrodite of formula Li6PS5Cl with carboxylated styrene-butadiene rubber to form a paste. The paste can then be calendered to form the first electrolyte in sheet form. The first electrolyte can then be dried in an optional additional step and then cut into the desired size and shape of an electrochemical cell.

[0209] The second electrolyte may contain a lithium salt, the salt at a concentration exceeding 75% of its saturation concentration. In this example, the liquid electrolyte may consist of lithium bis(fluorosphonyl)imide (LiFSI) dissolved to a molar concentration of 4.5 M so as to be within a 2:1 volume-to-volume ratio (v:v) of dimethoxyethane (DME):1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE).

[0210] A lithium metal foil with a thickness of 100 microns can be used as the negative electrode (anode).

[0211] The second electrolyte component may be held within an inert separator placed between the cathode and the first electrolyte.

[0212] Example 2 An electrochemical cell is provided.

[0213] The cathode contains 90% by weight of Black Pearls 2000(registered trademark) / S as the active material and 10% by weight of PEO as the binder. The cathode powder was prepared by a simple stirring and mixing method using a 3-roll mill. The binder was added in the second step to form an aqueous slurry, which was then coated onto an aluminum current collector to form the cathode.

[0214] The first electrolyte comprises 97% by weight of argyrodite of formula Li6PS5Cl and 3% by weight of poly(ethylene-co-acrylic acid).

[0215] The first electrolyte was prepared by mixing an argyrodite of formula Li6PS5Cl with carboxylated styrene-butadiene rubber to form a paste. The paste was then calendered to form the first electrolyte in sheet form. The first electrolyte was dried and then cut to the desired size and shape for the electrochemical cell.

[0216] The second electrolyte contains a lithium salt, the salt at a concentration exceeding 75% of its saturation concentration. In this example, the liquid electrolyte consists of lithium bis(fluorosphonyl)imide (LiFSI) dissolved to a molar concentration of 4M so that the volume-to-volume ratio (v:v) of dimethoxyethane (DME):1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) is within 3:1.

[0217] A 100-micron thick lithium metal foil was used as the negative electrode (anode).

[0218] The second electrolyte component was held within an inert separator placed between the cathode and the first electrolyte.

[0219] Figure 3 shows the characteristic electrochemical performance data of the cell.

[0220] It will be understood that the processes and apparatus of the present invention can be implemented in various ways, and only a few of these are illustrated and described above.

[0221] While the present invention has been described with reference to specific examples, it will be understood by those skilled in the art that the invention may be embodied in many other forms, and in particular, features of any one of the various described examples may be provided in any combination of any of the other described examples. Various modifications and changes to the present invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. It should be understood that the present invention is not intended to be unduly limited by the exemplary embodiments and examples described herein, and that such embodiments and examples are presented only as examples, within the scope of the invention which is intended to be limited only by the claims described herein as follows.

Claims

1. An electrochemical cell comprising an anode, a cathode and an electrolyte system, wherein the electrolyte system is (i) A first electrolyte containing a solid electrolyte, (ii) A second electrolyte comprising a liquid electrolyte, a gel electrolyte, or a combination thereof, An electrochemical cell in which the second electrolyte has sufficient polysulfide and / or polyselenide solubility to prevent shuttling, and the second electrolyte does not come into contact with the anode.

2. The electrochemical cell according to claim 1, wherein the first electrolyte comprises a ceramic material, a polymer material, or a combination thereof.

3. The first electrolyte is argyrodite, germanium phosphate sulfide lithium (LGPS-Li １０ GeP ２ S １２ An electrochemical cell according to claim 1 or 2, comprising ), lithium phosphorus sulfide (LPS), lithium lanthanum zirconium oxide (LLZO), aluminum germanium lithium phosphate (LAGP), lithium phosphorus oxynitride (LIPON), polyethylene oxide (PEO), or a combination thereof.

4. The electrochemical cell according to any one of the prior claims, wherein the first electrolyte comprises a binder including poly(ethylene-co-acrylic acid), carboxylated polystyrene, poly(ethylene-co-methacrylic acid), carboxylated nitrile butadiene rubber, carboxylated styrene butadiene rubber, or a combination thereof.

5. The electrochemical cell according to any one of the prior claims, wherein the ionic conductivity of the first electrolyte is in the range of 0.01 to 10 mS / cm.

6. The electrochemical cell according to any one of the prior claims, wherein the thickness of the first electrolyte is in the range of 5 μm to 100 μm.

7. The second electrolyte is linear ether, diethyl ether (DEE), tetrahydrofuran (THF), dimethoxyethane (DME), dioxolane (DIOX), diglym, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), methyl formate (MF), ethyl formate (EF), methyl propionate (MP), ethyl acetate (EA), and methyl butyrate (MB), methyl ethyl ketone, acetonitrile (ACN), propionitrile (PN), isobutyl An electrochemical cell according to any one of the prior claims, comprising a solvent selected from lenitrile (iBN), dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), tetramethylurea (TMU), dimethyl sulfoxide (DMSO), trimethyl phosphate, triethyl phosphate, hexamethylphosphoramide, toluene, benzene, heptane, xylene, dichloromethane, ionic liquids, fluorinated ethers, gels, or combinations thereof, and at least one alkali metal salt.

8. The electrochemical cell according to claim 7, wherein if the anode contains lithium or a lithium alloy, the alkali metal salt contains lithium, or if the anode contains sodium or a sodium alloy, the alkali metal salt contains sodium.

9. The alkali metal salt is at least one lithium salt selected from lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium perchlorate, lithium sulfate, lithium nitrate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethane)sulfonimide, lithium bis(fluorosulfonyl)imide, lithium bis(oxalate)borate, lithium difluoro(oxalate)borate, lithium bis(pentafluoroethanesulfonyl)imide, lithium 2-trifluoromethyl-4,5-dicyanoimidazole, and combinations thereof, or the alkali metal salt is hexafluoroarsenate, The electrochemical cell according to claim 8, wherein the sodium salt is selected from sodium xafluoroarsenate, sodium hexafluorophosphate, sodium perchlorate, sodium sulfate, sodium nitrate, sodium trifluoromethanesulfonate, sodium bis(trifluoromethane)sulfonimide, sodium bis(fluorosulfonyl)imide, sodium bis(oxalic acid)borate, sodium difluoro(oxalic acid)borate, sodium bis(pentafluoroethanesulfonyl)imide, sodium 2-trifluoromethyl-4,5-dicyanoimidazole, and at least one sodium salt selected from combinations thereof.

10. The electrochemical cell according to any one of the prior claims, wherein the concentration of the at least one alkali metal salt is at least 75% of the saturation concentration of the second electrolyte.

11. The electrochemical cell according to any one of the prior claims, wherein the electrolyte load of the second electrolyte is in the range of 0.1 μL / mAh to 3 μL / mAh.

12. An electrochemical cell according to any one of the prior claims, wherein the solubility of the polysulfide and / or polyselenide in the second electrolyte sufficient to prevent shuttling is less than 2 M, or less than 1 M, or less than 750 mM, or less than 500 mM, or less than 400 mM, or less than 200 mM, or less than 100 mM.

13. The electrochemical cell according to any one of claims 1 to 12, wherein the anode comprises an alkali metal, an alkali metal alloy, silicon, carbon, or a silicon-carbon composite material.

14. The electrochemical cell according to any one of the prior claims, wherein the first electrolyte has a first surface and a second opposing surface, the first surface being in contact with the surface of the anode and the second surface being in contact with the second electrolyte.

15. The electrochemical cell according to any one of the prior claims, wherein the cathode comprises (i) selenium, sulfur, or a combination thereof, and (ii) a carbonaceous material, a metallic material, a metalloid, a polymer, or a combination thereof.

16. The electrochemical cell according to claim 15, wherein the cathode comprises a carbon-sulfur composite material, a metal sulfide, a polymer-sulfur composite material, a carbon-selenium composite material, a carbon-sulfur-selenium composite material, a metal selenide, a polymer-selenium composite material, a metal sulfoselenide, a metalloid sulfide, a metalloid selenide, or a combination thereof.

17. The electrochemical cell according to any one of the prior claims, wherein the cathode is prelithiated or presozioated.

18. The electrochemical cell according to claim 17, wherein the cathode is prelithiated.

19. The electrochemical cell according to claim 17 or 18, wherein the cathode contains a metal sulfide containing molybdenum disulfide in the form of a 1T polymorph, the cathode is prelithiated, and the cathode further contains sulfur.

20. The electrochemical cell according to any one of the prior claims, wherein the cathode further comprises an ion-conducting material.

21. The electrochemical cell according to claim 20, wherein the ion-conducting material is selected from an ion-conducting ceramic material, an ion-conducting polymer, or a combination thereof.

22. A method for producing an electrolyte system according to any one of claims 1 to 12, (i) A step of producing a paste from a first electrolyte material, (ii) The step of calendering the paste to form a solid electrolyte, (iii) A method comprising the step of providing the second electrolyte, which comprises a liquid electrolyte, a gel electrolyte, or a combination thereof, wherein the second electrolyte has sufficient polysulfide and / or polyselenide solubility to prevent shuttling.

23. A method for generating a cell according to any one of claims 1 to 21, (i) The steps of forming the cathode from the cathode material and cutting the cathode into a desired shape, (ii) The step of forming the first electrolyte, (iii) The step of connecting the surface of the first electrolyte to the surface of the anode, (iv) A method comprising the step of providing the second electrolyte.

24. The method according to claim 23, further comprising calendering or press-forming the cathode before cutting.

25. An electrochemical cell assembly comprising at least one electrochemical cell as described in any one of claims 11 to 21, and means for applying pressure to the at least one electrochemical cell.

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