Lithium argyrodite oxide

Abstract

Provided herein is a lithium argyrodite oxide having the formula Li (6-y) PS4O (1-y) X (1 + y). Wherein X is a halide anion and y is a number between 0 and 0.8, including endpoints. Synthetic lithium argyrodite oxide and complexes including lithium argyrodite oxide, as well as other alkali metal oxide argyrodite, and related methods and complexes are also provided.

Description

This application is a divisional application of Chinese Patent Application No. 201980067972.3, titled "Lithium Oxide Argyrodite", with a filing date of September 19, 2019. Incorporated by reference

[0001] As part of this application, a PCT application form is submitted simultaneously with this specification. In the simultaneously submitted PCT application form, each application for which this application claims the benefit or priority thereof is incorporated herein by reference in its entirety and for all purposes. Background of the Invention

[0002] Compared with liquid electrolytes used in secondary batteries, solid electrolytes have various advantages. For example, in lithium-ion batteries, inorganic solid electrolytes may be less flammable than conventional liquid organic electrolytes. Solid electrolytes can also promote the use of lithium metal electrodes by preventing dendrite formation. Challenges in using solid electrolytes include low conductivity and poor electrochemical stability. Summary of the Invention

[0003] One aspect of the present invention relates to an argyrodite of the general formula: Li (6-y) PS4O (1-y) X (1+y) , where X is a halide and y is a number between 0 and 0.8. In some embodiments, y is between 0.5 and 0.7. In some embodiments, y is between 0.55 and 0.65. In some embodiments, y is between 0.3 and 0.5, for example, between 0.35 and 0.45. In some embodiments, y is one of about 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9. In some embodiments, the lithium oxide argyrodite is incorporated into a solid-state battery or a fuel cell. In some embodiments, the lithium oxide argyrodite is incorporated into or forms an electrolyte separator. In some embodiments, the lithium oxide argyrodite is incorporated into an electrode.

[0004] Another aspect of the present disclosure relates to a method for synthesizing lithium oxide argyrodite, comprising: adding stoichiometric amounts of Li2O and LiX to Li3PS4 and reacting Li2O, LiX, and Li3PS4 to form lithium oxide argyrodite Li (6-y) PS4O (1-y) X (1+y), where X is a halide and y is a number between 0 and 0.8. In some embodiments, the method further includes synthesizing Li3PS4. In some embodiments, Li2O, LiX, and Li3PS4 react without a solvent in a ball mill. In some embodiments, Li2O and LiX are added in a solvent. In some embodiments, the method further includes evaporating the solvent. In some embodiments, the solvent is ethanol. In some embodiments, the method further includes annealing the lithiogermanate.

[0005] Another aspect of the present disclosure is a solid electrolyte composition comprising a membrane, the membrane comprising an organic phase and a lithium-conductive inorganic phase, the organic phase including one or more polymers, the lithium-conductive inorganic phase comprising a lithiogermanate having the general formula Li (6-y) PS4O (1-y) X (1+y) , where X is a halide and y is a number between 0 and 0.8. In some embodiments, one or more polymers comprise a hydrophobic polymer. In some embodiments, one or more polymers are not ion-conductive. In some embodiments, one or more polymers include styrene ethylene butylene styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), styrene-ethylene / propylene-styrene (SEPS), and isoprene rubber (IR). In some embodiments, one or more polymers include a copolymer comprising plastic and elastic segments. In some embodiments, the membrane is between 0.5 wt% and 60 wt% polymer, 1 wt% and 40 wt% polymer, or 5 wt% and 30 wt% polymer.

[0006] Another aspect of the present disclosure is a slurry, paste, or solution comprising one or more solvents, polymers, and ion-conductive lithiogermanate particles. Another aspect of the present disclosure relates to an electrode comprising an active material, lithiogermanate, and an organic polymer.

[0007] Another aspect of the present disclosure is an alkali metal oxide lithiogermanate having the following formula: A (6-y) PS4O (1-y) X (1+y) where A is an alkali metal, X is a halide, and y is a number between 0 and 0.8, including the endpoints. Also provided are methods of synthesizing alkali metal oxide lithiogermanates and compositions and devices comprising them.

[0008] These and other aspects of the present disclosure are further discussed with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 shows the crystal structure of Li6PS5Cl.

[0010] Figure 2 shows an example crystal structure of Li6PS4OCl.

[0011] Figure 3 shows Li 5.5 PS4O 0.5 Cl 1.5 of the example crystal structure.

[0012] Figure 4 shows the X-ray diffraction patterns of Li6PS5Cl and Li6PS4OCl and Li 5.6 PS4O 0.6 Cl 1.4 .

[0013] Figure 5 shows the H2S release of Li6PS5Cl and Li6PS4OCl when exposed to air at 50% relative humidity (RH) and 75°F.

[0014] Figures 6A - 6C shows an example of a battery schematic including lithium thiogermanate oxide. Detailed Description

[0015] The present disclosure provides ion-conductive and electrochemically stable solid materials. Certain embodiments of these materials conform to Formula I: Li (6-y) PS4O (1-y) X (1+y) (Formula I) where X is a halide and y is a number between 0 and 0.8, inclusive. The material is a eutectic with the Formula I material and is also represented as Formula II: Li3PS4*(1-y)Li2O*(1+y)X (Formula II) where X is a halide and y is a number between 0 and 0.8, inclusive. In some embodiments, X is bromine (Br) or chlorine (Cl) such that the anion is bromine or chlorine. A mixed halide system is also provided, as well as embodiments of two halide systems given by Formula III: Li (6-y) PS4O (1-y )X 1 u X 2 z (Formula III) where X 1 and X 2 are halides, y is a number between 0 and 0.8, inclusive, and u + z = 1 + y.

[0016] Also provided are methods for manufacturing materials and storage batteries, as well as storage battery assemblies containing such materials. Introduction

[0017] The mineral argyrodite Ag8GeS6 can be considered a eutectic of Ag4GeS4 and two equivalents of Ag2S. Cations and anions can be substituted in this crystal while still retaining the same overall spatial arrangement of the various ions. For example, in the first lithium-containing instance of this mineral type, Li7PS6, the PS4 3- ions are located in the crystallographic positions occupied by GeS4 4- in the original mineral, while the S 2- ions retain their original positions, and the Li + ions occupy the positions of the original Ag + ions. Since there are fewer cations in Li7PS6 compared to the original Ag8GeS6, some cation sites are empty. These structural analogs of the original argyrodite minerals are also commonly referred to as argyrodites. Both Ag8GeS6 and Li7PS6 are orthorhombic crystals at room temperature, while a phase transition to a cubic space group occurs at high temperatures. Replacing one Li2S with another equivalent of LiCl results in the material Li6PS5Cl, which still retains the argyrodite structure but undergoes an orthorhombic-to-cubic phase transition below room temperature and has a significantly higher lithium-ion conductivity. Since the overall arrangement of cations and anions also remains the same in this material, it is also commonly referred to as an argyrodite. Other substitutions that also retain this overall structure can thus be called argyrodites.

[0018] Sulfide-based lithium argyrodite materials exhibit high Li + mobility and are of interest in lithium storage batteries. A typical material in this family is Li6PS5Cl, which is a ternary eutectic of Li3PS4, Li2S, and LiCl. Figure 1 The crystal structure of Li6PS5Cl is shown.

[0019] This material uses elements that are abundant on Earth and can have a high lithium-ion conductivity. Although it has advantages in solid-state lithium-ion electrolytes, it still has several disadvantages. The presence of lithium sulfide in the crystal structure means that it can release toxic and flammable hydrogen sulfide when absorbing moisture. In addition, although each component is relatively abundant on Earth, lithium sulfide is an expensive material compared to many other electrolyte components (including other lithium salts). Sulfide materials also generally have poor wetting interactions with lithium metal. This is a problem when constructing lithium metal anode storage batteries because poor surface interactions can lead to uneven deposition of lithium metal, resulting in uneven mechanical stress and dendrite growth in the battery.

[0020] This document provides thioargyrite of the general formula Li (6-y) PS4O (1-y) X (1+y) (also denoted as Li3PS4* (1-y) Li2O* (1+y) X), where X is a halide anion and y is a number between 0 and 0.8, inclusive of the endpoints. These materials can be referred to as lithium-oxide thioargyrite and have the same overall arrangement as Ag8GeS6 described above, where PS4 anions, X anions, and oxide anions are regularly arranged and there are lithium cations between them. The halide is typically Cl - or Br - , although it can be iodide or fluoride. In some embodiments, y is between 0 and 0.6. In certain embodiments, y is between 0.3 and 0.5 (inclusive of the endpoints) or between 0.35 and 0.45 (inclusive of the endpoints). In certain embodiments, y is between 0.5 and 0.7 (inclusive of the endpoints) or between 0.55 and 0.65 (inclusive of the endpoints). It should be noted that in some embodiments, the oxygen atoms of the LiO2 moiety can exchange positions with the S atoms of the PS4 moiety while maintaining the thioargyrite crystal structure. Unless otherwise specified, the general formula Li (6-y) PS4O (1-y) X (1+y) includes these embodiments.

[0021] Figure 2 and Figure 3 provide the crystal structures of two examples of lithium-oxide thioargyrite. Figure 2 Shows an example structure of Li6PS4OCl (y = 0), Figure 3 shows an example structure of Li 5.5 PS4O 0.5 Cl 1.5 (y = 0.5).

[0022] According to various embodiments, this family of materials can provide one or more of the following advantages. This material replaces some sulfur with the lighter element oxygen, so it can have a slight weight energy density advantage in the final electrochemical device. In addition, in terms of the degree to which lithium sulfide is replaced by lithium oxide, the production cost of this material is lower. Since there are no S 2- anions, there is no risk of immediately generating toxic hydrogen sulfide if this material comes into contact with atmospheric moisture or a large amount of water. (The PS4 3- anions will eventually degrade into hydrogen sulfide and PO4 3- , but this is an extremely slow process and is generally not considered dangerous).

[0023] In some embodiments, the use of lithium oxide argyrodite reduces the risk of dendrite formation. This may be because the lithium oxide component confers a more favorable surface interaction with lithium metal compared to most sulfide-based lithium ion conductors, including Li6PS5Cl, which increases the uniformity of lithium metal deposition. Synthesis

[0024] Also provided is a method for preparing the lithium oxide argyrodite described herein. The method includes adding Li2O and LiX to Li3PS4. In some embodiments, the method includes first generating Li3PS4 and then adding Li2O and LiX (such as LiCl). It should be noted that this is different from the production of sulfur-based argyrodite, in which the precursor compounds can be mixed for a mechanochemical reaction. For example, Li2S, P2S5, and LiCl can be mixed in a high-energy ball mill to produce Li6PS5Cl. However, if the required proportions of Li2S, Li2O, P2S5, and LiCl are mixed under the same conditions, much oxygen will participate in forming P-O bonds due to the competition between Li2S and Li2O before reacting with P2S5. This will result in residual Li2S in the structure, which in turn can lead to the formation of H2S when in contact with moisture.

[0025] In some embodiments, the method involves the solid-state preparation of Li3PS4, such as by reacting Li2S and P2S5 in a ball mill. The oxide and halide components can be added with further ball milling. Alternatively, the oxide and halide components can be added to a polar protic solvent such as ethanol and then the solvent is evaporated. In some embodiments, the method involves solution synthesis of Li3PS4 in a polar aprotic solvent such as ethyl propionate. Then the oxide and halide components can be added as described above.

[0026] After synthesizing the lithium oxide argyrodite, it can be annealed to increase the conductivity. The annealing can be carried out at a temperature close to the melting temperature. Example Synthesis Li6PS4OCl

[0027] Under an argon atmosphere, 3.568 g of Li3PS4 glass (previously produced by ball milling Li2S and P2S5 together), 0.592 g of Li2O, 0.840 g of LiCl, and 100 g of 10 mm spherical zirconia grinding media were placed into a 100 mL zirconia cup. The cup was hermetically sealed, and the contents were ground and mixed at 200 rpm on a Pulverisette 5 ball mill for 30 minutes. On the same mill, argyrodite was formed by grinding at 400 rpm for 20 hours with a reversal of direction every hour and without pauses between steps. After grinding, the cup was returned to the argon atmosphere, and the newly formed argyrodite was scraped from the cup wall. The material and the original zirconia media were returned to the cup, and the cup was sealed again. The argyrodite was ground at 200 rpm for 10 minutes. The cup was returned to the argon atmosphere again, the material was scraped out, and finally, through a stack of sieves, the fraction passing through a 25 μm sieve was collected. The as-prepared conductivity was measured, and the sample was annealed at 500 °C for 5 hours under an argon atmosphere. Li 5.6 PS4O 0.6 Cl 1.4

[0028] Under an argon atmosphere, 3.499 g of Li3PS4 glass (previously produced by ball milling Li2S and P2S5 together), 0.348 g of Li2O, 1.153 g of LiCl, and 100 g of 10 mm spherical zirconia grinding media were placed into a 100 mL zirconia cup. The cup was hermetically sealed, and the contents were ground and mixed at 200 rpm on a Pulverisette 5 ball mill for 30 minutes. On the same mill, argyrodite was formed by grinding at 400 rpm for 20 hours with a reversal of direction every hour and without pauses between steps. After grinding, the cup was returned to the argon atmosphere, and the newly formed argyrodite was scraped from the cup wall. The material and the original zirconia media were returned to the cup, and the cup was sealed again. The argyrodite was ground at 200 rpm for 10 minutes. The cup was returned to the argon atmosphere again, the material was scraped out, and finally, through a stack of sieves, the fraction passing through a 25 μm sieve was collected. The as-prepared conductivity was measured, and the sample was annealed at 500 °C for 5 hours under an argon atmosphere.

[0029] The conductivity of as-prepared Li6PS4OCl argyrodite was measured to be 0.42 mS / cm, which increased to 1.33 mS / cm after annealing. The conductivity of as-prepared Li 5.6 PS4O 0.6 Cl 1.4The conductivity of argyrodite is 1.54 mS / cm, which increases to 3.80 mS / cm after annealing. Raman spectroscopy shows the presence of Li3PS4 in the structure (as expected), with no sign of P-O bond formation. The conductivity is comparable to that of the reference material Li6PS5Cl (1.00 mS / cm as-prepared and 3.87 mS / cm after annealing).

[0030] Figure 4 Shows the X-ray diffraction patterns of Li6PS5Cl and Li6PS4OCl and Li 5.6 PS4O 0.6 Cl 1.4 The peaks marked with asterisks are related to the argyrodite structure. The two oxygen-containing materials (Li6PS4OCl and Li 5.6 PS4O 0.6 Cl 1.4 ) match well with the argyrodite structure. In these materials as well as the reference sample Li6PS5Cl, there are some small peaks that do not conform to the argyrodite structure, indicating the presence of small crystalline impurities.

[0031] Figure 5 Shows the H2S release of Li6PS5Cl and Li6PS4OCl when exposed to air at 50% relative humidity (RH) and 75°F. The peak H2S concentration produced by the oxygen-containing argyrodite is one-third of that of the reference argyrodite Li6PS5Cl, while the total integrated H2S release is 49% of the reference. Alkali metal oxide argyrodite Although lithium oxide argyrodite has been described above, argyrodites of other alkali metals are also provided herein. These include argyrodite of sodium oxide and argyrodite of potassium oxide. Accordingly, a composition according to Formula IV is also provided herein: A (6-y) PS4O (1-y) X (1+y) (Formula IV) Wherein A is an alkali metal, X is a halide, and y is a number between 0 and 0.8, inclusive. The material is a eutectic with the material of Formula I and is also represented as Formula V: A3PS4*(1 - y)A2O*(1 + y)X (Formula V) Wherein A is an alkali metal, X is a halide, and y is a number between 0 and 0.8, inclusive. In some embodiments, X is bromine (Br) or chlorine (Cl) such that the anion is bromine or chlorine. A mixed halide system is also provided, as well as embodiments of two halide systems given by Formula VI: A (6-y) PS4O (1-y) X 1 u X2 z (Formula VI) wherein A is an alkali metal, X 1 and X 2 are halides, y is a number between 0 and 0.8, inclusive of the endpoints, and u + z = 1 + y. In some embodiments, A is selected from lithium (Li), sodium (Na), and potassium (K). Formula I is a case of Formula II wherein A is Li. As described above, the general formula includes embodiments in which the oxygen and sulfur atoms exchange positions while maintaining the overall argyrodite structure. The argyrodites of sodium oxide and potassium oxide can be prepared in a manner similar to that described above for lithium oxide argyrodite. In addition, synthesis examples of Na6PS4OCl and Na 5.6 PS4O 0.6 Cl 1.4 are given below. Those of ordinary skill in the art will understand how to make modifications to synthesize other alkali metal argyrodites. Na6PS4OCl

[0032] Under an argon atmosphere, 3.273 g of Na3PS4 glass (previously produced by ball milling Na2S and P2S5 together), 0.889 g of Na2O, 0.838 g of NaCl, and 100 g of 10 mm spherical zirconia grinding media were placed in a 100 mL zirconia cup. The cup was hermetically sealed, and the contents were ground and mixed at 200 rpm on a Pulverisette 5 ball mill for 30 minutes. On the same mill, argyrodite was formed by grinding at 400 rpm for 20 hours, reversing the direction once per hour, with no pause between steps. After grinding, the cup was returned to the argon atmosphere, and the newly formed argyrodite was scraped from the cup wall. The material and the original zirconia media were returned to the cup, and the cup was sealed again. The argyrodite was ground at 200 rpm for 10 minutes. The cup was returned to the argon atmosphere again, the material was scraped out, and finally, the fraction passing through a 25 μm sieve was collected by stacked sieves. The conductivity of the as-prepared state was measured, and the sample was annealed in an argon atmosphere (e.g., at 500 °C) for 5 hours. Na 5.6 PS4O 0.6 Cl 1.4

[0033] Under an argon atmosphere, 3.286 g of Na3PS4 glass (previously produced by ball milling Na2S and P2S5 together), 0.536 g of Na2O, 1.178 g of NaCl, and 100 g of 10 mm spherical zirconia grinding media were placed in a 100 mL zirconia cup. The cup was hermetically sealed, and the contents were ground and mixed on a Pulverisette 5 ball mill at 200 rpm for 30 minutes. On the same mill, argyrodite was formed by grinding at 400 rpm for 20 hours, reversing the direction once per hour, with no pauses between steps. After grinding, the cup was returned to the argon atmosphere, and the newly formed argyrodite was scraped from the cup wall. The material and the original zirconia media were returned to the cup, and the cup was sealed again. The argyrodite was ground at 200 rpm for 10 minutes. The cup was returned to the argon atmosphere again, the material was scraped out, and finally, by a stack of sieves, the fraction passing through a 25 μm sieve was collected. The as-prepared conductivity was measured, and the sample was annealed in an argon atmosphere, for example, at 450 °C for 5 hours. Complexes comprising alkali metal oxide argyrodite

[0034] In some embodiments, lithium oxide argyrodite or argyrodite of other alkali metals can be mixed with a compliant material to form a composite solid ion conductor. The compliant material can be an organic phase, for example, as described in U.S. Patents 9,926,411 and 9,972,838 and U.S. Patent Application No. 16 / 241,784. The organic polymer phase can include one or more polymers and is chemically compatible with the inorganic ion-conducting particles. In some embodiments, the organic phase has substantially no ion conductivity and is referred to as "non-ion-conducting". The non-ion-conducting polymers described herein have an ion conductivity of less than 0.0001 S / cm.

[0035] In some embodiments, the organic phase includes a polymer binder, a relatively high molecular weight polymer. The molecular weight of the polymer binder is at least 30 kg / mol and can be at least 50 kg / mol or 100 kg / mol. In some embodiments, the polymer binder has a non-polar backbone. Examples of non-polar polymer binders include polymers or copolymers including styrene, butadiene, isoprene, ethylene, and butene. Styrene block copolymers including polystyrene blocks and rubber blocks can be used, and examples of rubber blocks include polybutadiene (PBD) and polyisoprene (PI). The rubber blocks can or can be hydrogenated. Specific examples of the polymer binder are styrene-ethylene-butene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-butadiene rubber (SBR), polystyrene (PSt), PBD, polyethylene (PE), and PI. Non-polar polymers do not coat the inorganic particles, which can lead to a decrease in conductivity.

[0036] Polymers of relatively low molecular weight can be used to improve the processability of polymers of relatively high molecular weight such as SEBS, e.g., by reducing the processing temperature and pressure. These can have a molecular weight of, for example, from 50 g / mol to 30 kg / mol. Examples include polydimethylsiloxane (PDMS), polybutadiene (PBD), and polystyrene. In some embodiments, the first component is a cyclic olefin polymer (COP). In some embodiments, the first component is a polyalkyl, polyaromatic, or polysiloxane polymer having end groups selected from cyano, thiol, amide, amino, sulfonic acid, epoxy, carboxyl, or hydroxyl.

[0037] The main or backbone chain of the polymer component of the organic phase does not interact with the inorganic phase. Examples of backbone chains include saturated or unsaturated polyalkyls, polyaromatics, and polysiloxanes. Examples of backbone chains that can interact too strongly with the inorganic phase include those having strong electron donor groups such as polyols, polyacids, polyesters, polyethers, polyamines, and polyamides. It should be understood that molecules having other moieties that reduce the binding strength of oxygen or other nucleophilic groups can be used. For example, the perfluorinated character of the perfluorinated polyether (PFPE) backbone delocalizes the electron density of the ether oxygen and allows their use in certain embodiments.

[0038] In some embodiments, a hydrophobic block copolymer having plastic and elastic copolymer segments is used. Examples include styrene block copolymers such as SEBS, SBS, SIS, styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), styrene-ethylene / propylene-styrene (SEPS), and isoprene rubber (IR).

[0039] In some embodiments, the organic phase is substantially non-ionic conductive. Examples of non-ionic conductive polymers include PDMS, PBD, and the other polymers described above. Unlike ionic conductive polymers such as polyethylene oxide (PEO), polypropylene oxide (PPO), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), etc., which are ionic conductive because they can dissolve or decompose salts such as LiI, non-ionic conductive polymers are not ionic conductive even in the presence of salts. This is because in the absence of salt dissolution, there are no mobile ions to conduct. In some embodiments, one or another of these ionic conductive polymers can be used. The PFPE described above and in Compliant glass-polymer hybrid single ion-conducting electrolytes for lithium ion batteries, PNAS, pp. 52 - 57, (2016), vol. 113, no. 1, which is incorporated herein by reference, is ionic conductive, is a single ion conductor for lithium, and can be used in some embodiments.

[0040] In some embodiments, ionic conductive polymers such as PEO, PPO, PAN, and PMMA can be used in the presence or absence of additional salts.

[0041] In some embodiments, the mixed solid ion conductor is formed from a precursor that is polymerized in situ after being mixed with inorganic particles. The polymerization can be carried out under an applied pressure that causes particle-to-particle contact. Once polymerized, the applied pressure can be removed by the particles immobilized by the polymer matrix. In some embodiments, the organic material includes a crosslinked polymer network. This network can constrain the inorganic particles and prevent them from moving during operation. The crosslinked polymer network can be crosslinked in situ, i.e., after the inorganic particles are mixed with the polymer or polymer precursor to form a composite. In situ polymerization of the polymer, including in situ crosslinking, is described in U.S. Patent No. 10,079,404, which is incorporated herein by reference.

[0042] The composites described herein can take various forms, including membranes and slurries or pastes that can be used to fabricate composite membranes. According to various embodiments, the composite can include one of the following: 1) A thiogermanate precursor without thiogermanate; and an organic polymer; 2) A thiogermanate precursor, thiogermanate, and an organic polymer; 3) Thiogermanate substantially without a precursor; and an organic polymer.

[0043] In some embodiments, the composite consists essentially of these components. In some other embodiments, additional components may be present, as further described below. As noted above, in some embodiments, the composite is provided in the form of a solid film. Depending on the specific composition and processing to date, the solid film can be provided in a device or be ready for incorporation into a device without further treatment, or the solid film can be prepared for in-situ processing of argyrodite as described above. In the latter case, it can be provided as a free-standing film or incorporated into a device for processing.

[0044] In certain embodiments, the loading of the polymer matrix in the hybrid composition can be relatively high, e.g., at least 2.5% to 30 wt%. According to various embodiments, it can be between 0.5 wt% to 60 wt% polymer, 1 wt% to 40 wt% polymer, or 5 wt% to 30 wt%. The composite forms a continuous film.

[0045] As noted above, the organic polymer is typically a non-polar hydrophobic polymer. In certain embodiments, it can be a polymer precursor (monomer, oligomer, or polymer) that is also processed in-situ for polymerization and / or crosslinking. Such treatment can be carried out during, before, or after the in-situ processing of argyrodite.

[0046] In some embodiments, argyrodite and / or its precursor accounts for 40 wt% to 95.5 wt% of the film. In some embodiments, the balance can be the organic polymer. In other embodiments, one or more additional components are present. Other components can include alkali metal ion salts, including lithium ion salts, sodium ion salts, and potassium ion salts. Examples include LiPF6, LiTFSI, LiBETI, etc. In some embodiments, the solid composition essentially does not include added salts. "Essentially free of added salts" means not more than trace amounts of salts. In some embodiments, if salts are present, their contribution to the ionic conductivity does not exceed 0.05 mS / cm or 0.1 mS / cm. In some embodiments, the solid composition can contain one or more conductivity enhancers. In some embodiments, the electrolyte can include one or more filler materials, including ceramic fillers such as Al2O3. If used, depending on the specific embodiment, the filler can be or can not be an ion conductor. In some embodiments, the composite can contain one or more dispersants. Additionally, in some embodiments, the organic phase of the solid composition can include one or more additional organic components to facilitate the manufacture of an electrolyte with the mechanical properties required for a specific application.

[0047] In some embodiments, which will be further discussed below, the solid composition is incorporated or is ready to be incorporated into an electrode and includes an electrochemically active material, and optionally an electronically conductive additive. Examples of the components and composition of an electrode including argyrodite are provided below.

[0048] In some embodiments, the electrolyte may include an electrode stabilizer that can be used to form a passivation layer on the electrode surface. Examples of electrode stabilizers are described in U.S. Patent 9,093,722. In some embodiments, the electrolyte may include a conductivity enhancer, a filler, or an organic component as described above.

[0049] In some embodiments, the composite is provided in the form of a slurry or paste. In this case, the composition contains a solvent to be evaporated later. Additionally, the composition may contain one or more components for storage stability. Such compounds may include acrylic resins. Once ready for processing, the slurry or paste can be appropriately cast or spread on a substrate and dried. Then, the in-situ processing as described above can be performed.

[0050] The solid composition can be prepared by any suitable method, using the exemplary procedures described below with reference to the experimental results. A uniform film can be prepared by a solution processing method. In one exemplary method, all the components are mixed together using laboratory and / or industrial equipment such as ultrasonicators, homogenizers, high-speed mixers, rotary mills, vertical mills, and planetary ball mills. A mixing medium can be added to assist in homogenization by improving mixing, breaking up agglomerates and aggregates, thereby eliminating film defects (such as pinholes and high surface roughness). The resulting mixture is in the form of a uniformly mixed slurry, the viscosity of which varies depending on the mixed composition and the solvent content. Substrates for casting can have different thicknesses and compositions. Examples include aluminum, copper, and polyester films. The slurry can be cast on a selected substrate by different industrial methods. In some embodiments, the porosity can be reduced by mechanical densification of the film (resulting in, for example, a thickness change of up to about 50%) by methods such as calendering between rollers, vertical flat pressing, or isostatic pressing. The pressure involved in the densification process forces the particles to maintain close intergranular contact. An external pressure of, for example, about 1 MPa to 600 MPa or 1 MPa to 100 MPa is applied. In some embodiments, the pressure applied by calendering rollers is used. Although the pressure is kept low enough to avoid extrusion of the uncured polymer from the press, the pressure is sufficient to create intergranular contact. Polymerization (which may include crosslinking) can occur under pressure to form a matrix. In some embodiments, thermally or photo-initiated polymerization techniques are used, where the application of heat energy or ultraviolet light is used to initiate the polymerization. The ion-conductive inorganic particles are trapped in the matrix and remain in close contact when the external pressure is released. The composite prepared by the above method can be, for example, a pellet or a film and can be incorporated into an actual solid-state lithium battery by well-established methods.

[0051] In some embodiments, the film is processed dry rather than in solution. For example, the film can be extruded. Extrusion or other dry processing can be an alternative to solution processing, particularly at higher loadings of the organic phase (e.g., in embodiments where the organic phase is at least 30 wt%). Device

[0052] The alkali metal oxide argyrodite can be incorporated into any device using an ion conductor, including but not limited to batteries and fuel cells. In a lithium battery, for example, lithium argyrodite oxide can be the electrolyte or incorporated into the electrolyte. Similarly, lithium argyrodite oxide can be incorporated into the electrodes. In some embodiments, lithium argyrodite oxide can be pressed or otherwise formed into a solid state ion conductor for use in a device. In some embodiments, lithium argyrodite oxide can be mixed with a compliant material to form a composite solid ion conductor as described above.

[0053] In some embodiments, the composite solid composition does not contain added salts. Due to the contact between the ion conductor particles, lithium salts (e.g., LiPF6, LiTFSI), potassium salts, sodium salts, etc. may not be required. In some embodiments, the solid composition consists essentially of ion-conductive inorganic particles and an organic polymer matrix. However, in alternative embodiments, one or more additional components can be added to the mixed solid composition.

[0054] The electrode composition further includes an electrode active material, and optionally a conductive additive. Examples of cathode and anode compositions are given below.

[0055] For the cathode composition, the following table gives examples of the composition.

[0056] According to various embodiments, the cathode active material is a transition metal oxide, exemplified by lithium nickel cobalt manganese oxide (LiMnCoMnO2 or NMC). Various forms of NMC can be used, including LiNi 0.6 Mn 0.2 Co 0.2 O2 (NMC-622), LiNi 0.4 Mn 0.3 Co 0.3 O2 (NMC-4330), etc. The lower limit of the wt% range is set by the energy density; compositions with less than 65 wt% active material have a low energy density and may not be useful.

[0057] Any suitable argyrodite can be used. Li 5.6 PS4O 0.6 Cl 1.4Examples of argyrodites that retain high ionic conductivity and suppress hydrogen sulfide. Compositions having less than 10 wt% argyrodite have low Li + conductivity.

[0058] An electron conductive additive can be used for active materials having low electron conductivity such as NMC. Carbon black is an example of such an additive, but other carbon-based additives can be used, including other carbon blacks, activated carbon, carbon fiber, graphite, graphene, and carbon nanotubes (CNT). Less than 1 wt% may not be sufficient to improve electron conductivity, while greater than 5 wt% results in a decrease in energy density and interference with active material - argyrodite contact.

[0059] Any suitable organic phase can be used. In certain embodiments, a hydrophobic block copolymer having plastic and elastic copolymer segments is used. Examples include styrene block copolymers such as styrene - ethylene / butylene - styrene (SEBS), styrene - butadiene - styrene (SBS), styrene - isoprene - styrene (SIS), styrene - isoprene / butadiene - styrene (SIBS), styrene - ethylene / propylene (SEP), styrene - ethylene / propylene - styrene (SEPS), and isoprene rubber (IR). Less than 1 wt% may not be sufficient to achieve the desired mechanical properties, while greater than 5 wt% results in a decrease in energy density and interference with active material - argyrodite - carbon contact.

[0060] For the anode composition, the following table gives examples of compositions.

[0061] Graphite is used as a secondary active material to improve the initial Coulombic efficiency (ICE) of the Si anode. A disadvantage of Si is its low ICE (e.g., less than 80% in some cases), which is lower than the ICE of NMC and other cathodes, resulting in irreversible capacity loss in the first cycle. Graphite has a high ICE (e.g., greater than 90%) and can make full use of the capacity. A hybrid anode using both silicon and graphite as active materials can provide a higher ICE, and an increasing graphite content means that the ICE of the anode can be matched to the ICE of the cathode by adjusting the Si / graphite ratio, thus preventing irreversible capacity loss in the first cycle. The ICE can vary with the process, depending on the specific anode and its process, allowing a relatively wide range of graphite content. Additionally, graphite improves electron conductivity and can contribute to the densification of the anode.

[0062] Any suitable argyrodite can be used. Any suitable argyrodite can be used. Li 5.6 PS4O 0.6 Cl 1.4Examples of argyrodites that retain high ionic conductivity and suppress hydrogen sulfide. Compositions having less than 10 wt% argyrodite have low Li + conductivity.

[0063] In some embodiments, a high surface area electronically conductive additive (such as carbon black) can be used. Si has low electronic conductivity, and such additives can also be helpful, except for graphite (which is a good electronic conductor but has a low surface area). However, in some embodiments, the electronic conductivity of the Si alloy can be quite high, such that the use of additives is not required. Other high surface area carbons (carbon black, activated carbon, graphene, carbon nanotubes) can also be used in place of Super C.

[0064] Any suitable organic phase can be used. In certain embodiments, a hydrophobic block copolymer having plastic and elastic copolymer segments is used. Examples include styrene block copolymers such as styrene-ethylene / butylene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), styrene-ethylene / propylene-styrene (SEPS), and isoprene rubber (IR). Less than 1 wt% may not be sufficient to achieve the desired mechanical properties, while greater than 5 wt% results in a reduced energy density and interferes with the contact of the active material - argyrodite - carbon.

[0065] Provided herein are alkali metal batteries and alkali metal ion batteries that include an anode, a cathode, and a compliant solid electrolyte composition as described above that is operably associated with the anode and cathode. The battery can include a separator for physically separating the anode and cathode; this can be the solid electrolyte composition.

[0066] Examples of suitable anodes include, but are not limited to, anodes formed from lithium metal, lithium alloys, sodium metal, sodium alloys, carbonaceous materials such as graphite, and combinations thereof. Examples of suitable cathodes include, but are not limited to, cathodes formed from transition metal oxides, doped transition metal oxides, metal phosphates, metal sulfides, lithium iron phosphate, sulfur, and combinations thereof. In some embodiments, the cathode can be a sulfur cathode.

[0067] In alkali metal - air batteries such as lithium - air batteries, sodium - air batteries, or potassium - air batteries, the cathode can be permeable to oxygen (such as mesoporous carbon, porous aluminum, etc.), and the cathode can optionally contain a metal catalyst (such as a manganese, cobalt, ruthenium, platinum, or silver catalyst, or a combination thereof) incorporated therein to enhance the reduction reaction that occurs with lithium ions and oxygen at the cathode.

[0068] In some embodiments, a lithium-sulfur battery is provided, comprising a lithium metal anode and a sulfur-containing cathode. In some embodiments, the solid composite electrolytes described herein uniquely enable lithium metal anodes and sulfur cathodes by preventing dendrite formation and by not dissolving polysulfide intermediates formed at the cathode during discharge.

[0069] A separator formed of any suitable material permeable to ion flow may also be included to prevent the anode and cathode from making direct electrical contact with each other. However, since the electrolyte compositions described herein are solid compositions, they can be used as separators, particularly when they are in the form of membranes.

[0070] In some embodiments, the solid electrolyte composition is used as the electrolyte between the anode and cathode in an alkali ion storage battery that relies on the insertion of alkali ions during cycling.

[0071] As described above, in some embodiments, the solid composite composition can be incorporated into the electrodes of a storage battery. The electrolyte can be the compliant solid electrolyte described above or any other suitable electrolyte, including liquid electrolytes.

[0072] In some embodiments, the storage battery includes an electrode / electrolyte bilayer, where each layer incorporates the ion-conductive solid composite material described herein.

[0073] Figure 6A An example of a schematic diagram of a battery according to certain embodiments of the present invention is shown. The battery includes a negative current collector 602, an anode 604, an electrolyte / separator 606, a cathode 608, and a positive current collector 610. The negative current collector 602 and the positive current collector 610 can be any suitable electronically conductive material, such as copper, steel, gold, platinum, aluminum, and nickel. In some embodiments, the negative current collector 602 is copper and the positive current collector 610 is aluminum. The current collectors can be in any suitable form, such as a sheet, foil, mesh, or foam. According to various embodiments, one or more of the anode 604, cathode 608, and electrolyte / separator 606 are solid composites that include a sulfurophilic metal-doped argyrodite as described above. In some embodiments, as described above, two or more of the anode 604, cathode 608, and electrolyte 606 are solid composites that include a sulfurophilic metal-doped argyrodite.

[0074] In some embodiments, the current collector is a porous body that can be embedded in the corresponding electrode. For example, it can be a mesh. Electrodes containing the above-mentioned hydrophobic polymers may not adhere well to current collectors in the form of foils; however, the mesh provides good mechanical contact. In some embodiments, two of the composite membranes described herein can be pressed onto the mesh current collector to form an embedded current collector in the electrode.

[0075] Figure 6BFIG. shows a schematic example of a lithium metal battery assembled according to certain embodiments of the present invention. The assembled battery includes a negative current collector 602, an electrolyte / separator 606, a cathode 608, and a positive current collector 610. Lithium metal is generated and plated on the negative current collector 602 during the first charge to form an anode. One or both of the electrolyte 606 and the cathode 608 can be the composite materials as described above. In some embodiments, the cathode 608 and the electrolyte 606 together form an electrode / electrolyte bilayer. Figure 6C FIG. shows a schematic example of a battery according to certain embodiments of the present invention. The battery includes a negative current collector 602, an anode 604, a cathode / electrolyte bilayer 612, and a positive current collector 610. Each layer in the bilayer can include argyrodite. For example, such a bilayer can be prepared by preparing an electrolyte slurry and depositing it on an electrode layer.

[0076] According to known techniques, all components of a storage battery can be included or packaged in a suitable rigid or flexible container having external leads or contacts for establishing electrical connections to the anode and cathode.

[0077] In the above description and claims, a numerical range includes the endpoints of the range. For example, "y is a number between 0 and 0.8" includes 0 and 0.8. Similarly, a range indicated by a dash includes the endpoints of the range.

Claims

1. Lithium germanium oxysulfide, with the general formula: Li (6-y) PS4O (1-y) X (1+y) , where X is a halide and y is a number between 0 and 0.

8.

2. The lithium germanium oxysulfide according to claim 1, wherein y is between 0.5 and 0.

7.

3. The lithium germanium oxysulfide according to claim 1, wherein y = 0.

4. The lithium germanium oxysulfide according to claim 1, wherein y = 0.

1.

5. The lithium germanium oxysulfide according to claim 1, wherein y = 0.

2.

6. The lithium germanium oxysulfide according to claim 1, wherein y = 0.

3.

7. The lithium germanium oxysulfide according to claim 1, wherein y = 0.

4.

8. The lithium germanium oxysulfide according to claim 1, wherein y = 0.

5.

9. The lithium germanium oxysulfide according to claim 1, wherein y = 0.

6.

10. The lithium germanium oxysulfide according to any one of the above claims, wherein the lithium germanium oxysulfide is incorporated into a solid-state battery or a fuel cell.

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