Composite cathode for all-solid-state batteries, method for manufacturing the same, and all-solid-state battery thereof

Abstract

A composite cathode, a method for manufacturing the composite cathode, and an all-solid-state battery comprising the composite cathode are disclosed. The composite cathode comprises a plurality of sulfur particles having an arithmetic mean particle size of 5 μm to 10 μm; a plurality of sulfur-containing solid electrolyte particles of the formula Li6PS5X (wherein X = Cl, Br, or I); and a conductive material comprising a plurality of acetylene black carbon particles. The acetylene black carbon particles have an average particle size of 10 nm to 100 nm, a BET specific surface area of ​​50 m²g⁻¹ to 150 m²g⁻¹, and a quasicrystalline structure. The sulfur particles, the sulfur-containing solid electrolyte particles, and the conductive material are ball-milled to form a milled mixture, and the composite cathode is formed by applying pressure.

Description

Technology Field

[0001] Cross-reference regarding related applications

[0002] This application claims the benefit of priority based on U.S. Provisional Application No. 63 / 623,546 filed January 22, 2024, U.S. Provisional Application No. 63 / 555,694 filed February 20, 2024, and U.S. Regular Application No. 18 / 778,467 filed July 19, 2024, the whole of which is expressly incorporated herein by reference in its entirety.

[0003] Technology field

[0004] The present disclosure relates to a composite positive electrode for an all-solid-state battery comprising: sulfur particles having an average particle size of 5 μm to 10 μm; sulfur-containing solid electrolyte particles of the formula Li6PS5X (wherein X = Cl, Br, or I); and acetylene black carbon particles. Additionally, an all-solid-state battery comprising the composite positive electrode, and a method for manufacturing the composite positive electrode and the battery are also described. Background Technology

[0005] The use of electric transportation continues to increase, represented by the widespread adoption of electric vehicles (EVs) and the emergence of Urban Air Mobility (UAM) vehicles. At the same time, there is a growing demand for stationary energy storage systems powered by solar and wind power, particularly in the residential and industrial sectors. These changes are being driven in part by the urgent need to mitigate the adverse environmental and climate impacts associated with traditional internal combustion engines and other non-renewable power sources. Consequently, the development of battery technologies that ensure high energy density while guaranteeing enhanced safety has become essential.

[0006] Conventional liquid lithium-ion batteries have been crucial to the development of electric transport and energy storage systems, and have had a significant positive impact on green energy and climate change mitigation efforts. While these conventional liquid lithium-ion batteries are superior to many other energy sources, they do have certain limitations. For example, various safety mechanisms are important in lithium-ion batteries to limit voltage and internal pressure, but these safety features generally result in increased weight and performance limitations in certain cases. Furthermore, lithium-ion batteries are prone to aging; after years of use, capacity is lost and failure eventually occurs.

[0007] In all-solid-state batteries (ASSB), a solid electrolyte is used instead of a liquid electrolyte, making the entire battery solid. Solid electrolytes are inherently non-flammable and can accommodate a wider temperature range, allowing them to function as electrochemical energy storage without the need for additional safety devices. Solid-state batteries provide higher energy density and are safer than batteries based on liquid electrolyte systems, such as conventional lithium-ion batteries. In conventional solid-state batteries, safety is enhanced by replacing the liquid electrolyte system with a solid electrolyte, thereby reducing the risk of ignition or explosion.

[0008] For example, a lithium-sulfur battery using lithium and alkali metals as negative electrode active materials and sulfur as positive electrode active material has a theoretical energy density of 2,800 Wh / kg (1,675 mAh g -1Sulfur is attracting attention as a material for portable electronic devices due to its advantages as an inexpensive and eco-friendly material, and its significantly higher energy density compared to other battery systems. Lithium metal is advantageous because it is lightweight, which allows for the realization of potentially high energy density. Various cathode active materials, such as sulfur-containing cathode active materials with sulfur-sulfur bonds, can be used in lithium batteries, which possess high energy capacity due to the 16-electron conversion reaction that forms Li2S in a reduced state. However, when sulfur is used as the cathode active material in lithium-sulfur batteries, it is difficult for electrons and lithium ions generated by electrochemical reactions to move because sulfur is a non-conductor. Furthermore, in the case of sulfur cathodes, there is a problem of performance and lifespan degradation due to large volume changes during charging and discharging.

[0009] Therefore, there is a high demand for technologies in ASSB technology that increase energy density and improve cycle characteristics and lifespan. The problem to be solved

[0010] The present disclosure relates to a composite anode, a method for manufacturing a composite anode, and an all-solid-state battery comprising a composite anode. means of solving the problem

[0011] The composite anode comprises (i) a plurality of sulfur particles having an arithmetic mean particle size of 5 μm to 10 μm; (ii) a plurality of sulfur-containing solid electrolyte particles of the formula Li6PS5X (where X = Cl, Br, or I); and (iii) a mean particle size of 10 nm to 100 nm and a Brunauer-Emmett-Teller (BET) specific surface area of ​​50 m² 2 g -1 up to 150m 2 g -1It includes a plurality of acetylene black carbon particles having a para-crystalline structure. The sulfur particles, sulfur-containing solid electrolyte particles, and conductive material are ball-milled to form a milled mixture; and a composite anode is formed by applying pressure.

[0012] Some aspects provide a plurality of sulfur particles having an arithmetic mean particle size of 5 μm to 10 μm; a plurality of sulfur-containing solid electrolyte particles of the formula Li6PS5X (wherein X = Cl, Br, or I); and an average particle size of 10 nm to 100 nm and a BET specific surface area of ​​50 m² 2 g -1 up to 150m 2 g -1 The present invention relates to a method for manufacturing a composite anode, comprising: providing a plurality of acetylene black carbon particles having a quasicrystalline structure; milling the sulfur particles, sulfur-containing solid electrolyte particles, and conductive material to form a milled mixture; and pressurizing the milled mixture to form a composite anode. Some aspects relate to a composite anode manufactured according to this method.

[0013] In one aspect, milling is performed at 200-500 rpm, preferably 300-500 rpm, more preferably 400-500 rpm.

[0014] In one aspect, milling is performed for 30 minutes to 2 hours, preferably 30 minutes, preferably 1 hour.

[0015] In one aspect, the milled mixture is pressurized at a pressure of 100 MPa to 500 MPa, for example, 150 MPa to 375 MPa. In some aspects, the pressurization is performed for 1 minute to 60 minutes.

[0016] Some aspects relate to an all-solid-state battery comprising a cathode; a composite anode as described herein; and a solid electrolyte. Preferably, the composite anode comprises a sulfur channel in contact with the solid electrolyte. Such a sulfur channel may have a channel diameter in the range of 10 to 40 microns.

[0017] Some aspects relate to composite anodes containing amorphous sulfur.

[0018] In some aspects, the sulfur particles, sulfur-containing solid electrolyte particles, and conductive material used to prepare the milled mixture are provided in a weight ratio of 20-50:40-60:10-30, preferably 25-35:45-55:15-25, or more preferably 30:50:20.

[0019] In some aspects, multiple sulfur-containing solid electrolyte particles are of the formula Li6PS5Cl.

[0020] In another aspect, the multiple acetylene black carbon particles have an average particle size of 40 nm.

[0021] In some aspects, multiple acetylene black carbon particles have a BET specific surface area of ​​90 m² 2 g -1 am.

[0022] In some aspects, multiple acetylene black carbon particles are non-porous.

[0023] In some aspects, multiple acetylene black carbons have a quasicrystalline structure.

[0024] Each side may have one or more additional elements in any combination. Brief explanation of the drawing

[0025] The accompanying drawings illustrate aspects of the present disclosure and serve to further enhance understanding of the technical concept of the present disclosure together with the detailed disclosure; the present disclosure should not be interpreted as being limited to the drawings. In the drawings, the shape, size, scale, or proportion of elements may be exaggerated for clarity of explanation. Figures 1a and 1b show the PXRD diffraction pattern and Raman spectrum for the milled anode material of Synthesis Example 1. Figure 2a shows an SEM image of ball-milled sulfur. Figure 2b shows an SEM image of milled LPSCl. Figure 2c shows an SEM image of an anode mixture of LPSCl, sulfur, and acetylene black (AB). Fig. 3a is 1.6 mAh g -1 Voltage when operating at vs. Li + Capacity as a function of / Li(V) (mAh g -1 The test results for ). Fig. 3b shows 1.6mAh g -1 Specific capacity as a function of the number of cycles when operating (mAh g -1 Displays the results for ). Fig. 4a shows the device used for testing, with 5 mAh cm⁻¹. -2 , Li1In1 available capacity 110mAh g -1 and illustrates a device that is a fixed gap holder with an NP ratio of 2. FIG. 4b shows voltage vs. Li + S capacity (mAh g) as a function of / Li(V) -1 Figure 4c illustrates the results for ). S capacity (mAh g) as a function of the number of cycles. -1 Displays the results for ). Fig. 5a shows a constant pressure of 10 MPa, 1.6-5 mAh cm⁻¹. -2 From (Literature [S.-Y. Ham et al ., Energy Storage MaterialsFigure 5b illustrates the experimental setup used according to [55:455-462 (2023)]. Voltage vs. Li + S capacity (mAh g) as a function of / Li(V) -1 1.6mAh cm for ) -2 The results of Experimental Example 1 when tested at are shown. Fig. 5c shows voltage vs. Li + S capacity (mAh g) as a function of / Li(V) -1 5mAh cm for ) -2 The results of Experimental Example 1 when tested in [location] are illustrated. Fig. 6a is 1.6 mAh cm⁻¹ -2 S capacity as a function of the number of cycles measured at (mAh g -1 Figure 6b illustrates the results for ). Figure 6b is 5 mAh cm -2 S capacity as a function of the number of cycles measured at (mAh g -1 Displays the results for ). Figures 7a–f illustrate test results for the performance of elemental sulfur all-solid-state cells using chloride and sulfide-based electrolytes. Voltage profiles and cycling performance of LZC (see Figures 7a and 7b), LYC (see Figures 7c and 7d), and LPSCl (see Figures 7e and 7f) are shown when used as ion conductors within the anode complex. Figure 7g illustrates a comparison of the results of the milled anode shown in Figure 7e. Figure 8a shows the SEM image and EDS mapping of the surface of a μm sulfur composite electrode in a pristine state. Figure 8b shows the SEM image and EDS mapping of the surface of a μm sulfur composite electrode in a cycled state. Figure 9a is an XRD diffraction pattern illustrating the amorphous transformation of the milled S / LPSCl composite according to various milling times. As the milling time increases, the amorphous transformation of sulfur in the S / LPSCl composite is evident. Figure 9b is an XRD diffraction pattern illustrating the amorphous transformation of the milled S / LPSCl / C composite according to various milling times. Fig. 10a demonstrates the size effect of the LPSCl solid electrolyte on the first-cycle voltage profile comparing micron and secreted LPSCl at 5 mAh cm⁻¹. -2 The electrochemical performance in terms of areal capacity is illustrated. Fig. 10b shows SEM images of micron and secreted LPSCl solid electrolytes. Specific details for implementing the invention

[0026] Best form for carrying out the invention

[0027] The present disclosure is described in detail below. It should be understood that terms and words used in this specification and the appended claims should not be interpreted as being limited to their general or dictionary meanings, but should be interpreted based on meanings and concepts consistent with the technical spirit of the present disclosure, in accordance with the principle that the inventor may appropriately define terms for the best description. Accordingly, it should be understood that the aspects of the present disclosure described herein and the elements illustrated in the drawings are merely aspects of the present disclosure and do not fully represent the technical spirit of the present disclosure, and that other equivalents and variations may exist at the time of filing this application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as generally known to those skilled in the art. In the event that there are multiple definitions of terms in this specification, the definition provided herein shall prevail.

[0028] Unless otherwise specified, all percentages, parts, and ratios in this disclosure are by weight.

[0029] Unless otherwise noted, the numeric parameters described in the following specification and appended claims are approximations that may vary depending on the desired characteristics to be obtained according to aspects of this disclosure. Whenever a numeric range having a lower and an upper limit is disclosed, any numeric value and any inclusion range falling within that range are specifically disclosed. In particular, all ranges of values ​​disclosed herein (in the form of “about a to about b”, or the equivalent “about a to b”, or the equivalent “about ab”) should be understood as describing all numbers and ranges included within a broader range of values.

[0030] Although compositions and methods are described herein using the term “comprising” various components or steps, it is also possible that such compositions and methods are “essentially composed of” or “comprising” various components and steps. As used herein, the term “comprising” specifies the presence of a mentioned element, but does not exclude the presence or addition of one or more other elements unless otherwise clearly indicated in the context.

[0031] In this specification, the terms “about” and “substantially” are used to mean “at that value” or “approximately that value” when manufacturing and material tolerances inherent to the situation being mentioned are presented, and are used to prevent unscrupulous infringers from unjustly appropriating the benefits of this disclosure when precise or absolute values ​​are mentioned to aid in understanding this disclosure. When used with numerical variables, the terms “about” and “approximately” generally mean the value of the variable, and any value of the variable within experimental error (e.g., a 95% confidence interval for the mean) or within ±10% of a specified value or a broader range. Unless otherwise indicated, all numerical values ​​representing the amount of a component, characteristics such as molecular weight, reaction conditions, etc., used in this specification and the related claims should be understood as being modifiable by the term “about.”

[0032] As used in this specification, "A and / or B" specifies "A or B or both."

[0033] The term "average particle size" as used herein refers to the particle size obtained as the arithmetic mean observed using a scanning electron microscope (SEM).

[0034] The term "mean particle size" as used herein refers to the average particle size observed using SEM.

[0035] <Composite Anode>

[0036] In one aspect, the composite anode is manufactured from a mixture comprising a plurality of sulfur particles, a plurality of sulfur-containing solid electrolyte particles, and a plurality of acetylene black carbon particles, which are ball-milled to form a milled mixture, and then pressurized to form the composite anode.

[0037] Another aspect concerns the method of manufacturing the composite anode.

[0038] Another aspect relates to an all-solid-state battery comprising an anode; the aforementioned composite cathode; and a solid electrolyte. In particular, the all-solid-state battery may be a lithium metal all-solid-state battery (Li-ASSB) which has the advantage of avoiding organic materials (which may react or cause a risk of combustion).

[0039] In some aspects, the composite anode includes sulfur channels in contact with a solid electrolyte. These sulfur channels can be probabilistically distributed within the anode composite with channel diameters ranging from 10 to 40 microns as shown in FIG. 8b.

[0040] As discussed below, the anode may be manufactured by providing a plurality of sulfur particles having an arithmetic mean particle size of 5 μm to 10 μm; a plurality of sulfur-containing solid electrolyte particles of the formula Li6PS5X (wherein X = Cl, Br, or I); and a plurality of acetylene black carbon particles. Preferably, the plurality of acetylene black carbon particles have an average particle size of 10 nm to 100 nm and a BET specific surface area of ​​50 m² 2 g -1 up to 150m 2 g -1 It has a quasicrystalline structure. The sulfur particles, sulfur-containing solid electrolyte particles, and conductive material are milled to form a milled mixture. The milled mixture is pressed to form a composite anode.

[0041] The arithmetic mean particle size of the sulfur particles used to manufacture the composite cathode may be 5 μm to 10 μm. The lower limit of the arithmetic mean particle size of the sulfur particles may be 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, or 9.5 μm. The upper limit of the arithmetic mean particle size of the sulfur particles may be 9.5 μm, 9 μm, 8.5 μm, 8 μm, 7.5 μm, 7 μm, 6.5 μm, 6 μm, or 5.5 μm.

[0042] Sulfur particles can be used exactly as received in their commercial form.

[0043] Sulfur particles can be milled individually before being combined with sulfur-containing solid electrolyte particles and acetylene black carbon particles.

[0044] In another aspect, lithium sulfide particles may be used instead of sulfur particles. In some aspects, sulfur particles may be combined with lithium sulfide (Li2S). When using lithium sulfide, the lithium sulfide may be processed in the same manner as described herein for sulfur particles. Any commercial grade of lithium sulfide may be used as received, preferably in powder and anhydrous forms. When using lithium sulfide particles, they are preferably on a micron scale, for example, within 5 μm to 30 μm. The lithium sulfide particles are ball-milled using the same conditions as described herein for sulfur particles. Preferably, when milling lithium sulfide particles, the composite particles are retained after ball milling (e.g., ball milling at 500 rpm for 1 hour). For example, after ball-milling the lithium sulfide particles, sulfide-based solid electrolyte (LPSCl), and conductive material in the same manner as discussed below for sulfur particles, a cathode is formed by applying pressure. For lithium sulfide particles as well, the same amounts and concentrations as described herein for sulfur particles may be used. For example, in one aspect, the ratio of Li2S particles:LPSCl:acetylene black (AB) carbon may be 30:50:20 weight%.

[0045] The sulfur-containing solid electrolyte particles are preferably of the formula Li6PS5X (wherein X = Cl, Br, or I). In one aspect, a plurality of sulfur-containing solid electrolyte particles are of the formula Li6PS5Cl.

[0046] In certain aspects, the arithmetic mean size of the sulfur-containing solid electrolyte particles is 5-10 μm. The lower limit of the arithmetic mean particle size of the sulfur particles may be 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, or 9.5 μm. The upper limit of the arithmetic mean particle size of the sulfur particles may be 9.5 μm, 9 μm, 8.5 μm, 8 μm, 7.5 μm, 7 μm, 6.5 μm, 6 μm, or 5.5 μm.

[0047] Fig. 10a demonstrates the size effect of the LPSCl solid electrolyte on the first-cycle voltage profile comparing micron and secreted LPSCl at 5 mAh cm⁻¹. -2 The electrochemical performance in terms of area capacity is illustrated. Fig. 10b shows SEM images of micron and secreted LPSCl solid electrolytes.

[0048] The acetylene black carbon particles preferably have an average particle size of 10 nm to 100 nm. In one aspect, the plurality of acetylene black carbon particles have an average particle size of 20 nm to 80 nm. In one aspect, the plurality of acetylene black carbon particles have an average particle size of 30 nm to 70 nm, or an average particle size of 40 nm.

[0049] Acetylene black carbon particles preferably have a BET specific surface area of ​​50 m² 2 g -1 up to 150m 2 g -1 , 75m 2 g -1 to 125m 2 g -1 , 80m 2 g -1 to 100m 2 g -1 or 90m 2 g -1 am.

[0050] Acetylene black carbon particles may preferably have a crystalline structure. The crystalline structure may include a continuous crystalline structure, for example, single-crystal acetylene black carbon. Alternatively, the acetylene black carbon may include one or more crystal grains in the continuous crystalline structure, for example, polycrystalline or multi-crystalline silicon.

[0051] In certain aspects, multiple acetylene black carbons have a quasicrystalline structure that is neither completely amorphous nor completely crystalline. In quasicrystalline materials, acetylene black carbons exhibit short-range and / or mid-range order in their crystal structure but lack long-range order in at least one direction.

[0052] In certain aspects, acetylene black carbon particles are non-porous.

[0053] In certain aspects, the anode may further include an additional anode active material, or optionally, an additional electrically conductive material to promote electron movement in the anode, and / or a binder for attaching the anode active material to a current collector.

[0054] For example, the additional anode conductive material may be at least one conductive material selected from the group consisting of, for example, graphite, carbon black, carbon fiber, carbon nanotube, or metal fiber, metal powder, conductive whisker, conductive metal oxide, activated carbon, or polyphenylene derivative.

[0055] Additional conductive materials are not particularly limited and may be used alone or in combination with other conductive materials such as graphite-based materials like KS6, carbon-containing materials such as Super-P, Denka Black, and carbon black, or conductive polymers such as polyaniline, polythiophene, polyacetylene, and polypyrrole. For example, the additional anode conductive material may be at least one conductive material selected from the group consisting of natural graphite, artificial graphite, Super-P, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, Denka black, aluminum powder, nickel powder, zinc oxide, potassium titanate, and titanium oxide.

[0056] Optionally, a binder may be used in the anode. Regarding the content of the binder, the binder may be added in an amount of 0.5 to 30 weight percent based on the total weight of the mixture containing the anode active material. If the content of the binder is less than 0.5 weight percent, there is a problem where the physical properties of the anode deteriorate and the active material and conductive material within the anode are lost, and if the content exceeds 30 weight percent, the ratio of the active material and conductive material within the anode decreases relatively, which may reduce the battery capacity and is undesirable.

[0057] As the binder mentioned above, it is possible to use poly(vinyl acetate), polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, alkylated polyethylene oxide, cross-linked polyethylene oxide, polyvinyl ether, poly(methyl methacrylate), polyvinylidene fluoride, copolymer of polyhexafluoropropylene and polyvinylidene fluoride (trade name: Kynar), poly(ethyl acrylate), polytetrafluoroethylene, polyvinyl chloride, polyacrylonitrile, polyvinylpyridine, polystyrene, derivatives thereof, blends, copolymers, etc.

[0058] For example, the anode binder resin mentioned above may be a polymer for anodes that is commonly used in the relevant technical field. Non-limiting examples of binder resins include, but are not limited to, polyvinylidene difluoride, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethyl methacrylate, polyethylhexyl acrylate, polybutyl acrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, and carboxymethyl cellulose.

[0059] Meanwhile, in some aspects of the present disclosure, the anode is 5 mAh / cm 2 Above, 6mAh / cm² 2 Above, or 10mAh / cm² 2 It can have a load amount (per anode area) greater than or equal to the above. In the battery according to the present disclosure, when a high-load anode is applied, it is possible to operate the battery at an electrochemically stable level.

[0060] In a specific aspect, sulfur particles, sulfur-containing solid electrolyte particles, and a conductive material are ball-milled to form a milled mixture.

[0061] The present disclosure utilizes a single-step manufacturing method through ball milling, which is a simple and convenient method that avoids complex processes such as conventional multi-step methods or the deposition of sulfur onto solid electrolyte / carbon composites. It should be noted that the deposition technique cannot create 3D structures, and thus the transport pathway to the solid electrolyte surface is limited. As illustrated in FIGS. 8a and 8b, it is noted that after cycling, sulfur channels maintaining good contact with the solid electrolyte are observed, thereby enhancing excellent performance. FIGS. 8a shows an SEM image and EDS mapping of the surface of the μm sulfur composite anode in an untreated state. FIGS. 8b shows an SEM image and EDS mapping of the surface of the μm sulfur composite anode in a cycled state.

[0062] The composite anode can be manufactured by mechanically mixing sulfur particles, sulfur-containing solid electrolyte particles, and a conductive material. Milling can be performed using a suitable device. For example, an Emax high-power mill can be used. In some aspects, 5 mm balls can be used for milling. In some aspects, the composite anode mixture can be formed by hand mixing or using a planetary ball milling device. For example, a planetary ball mill can be used to grind sample materials to very small sizes. A planetary ball mill consists of at least one grinding jar eccentrically arranged on a so-called sun wheel.

[0063] Mixing may be performed by a dry mixing method. First, an anode material comprising an anode active material, a conductive material, and a binder resin is placed in a mixing device and mixed by a mechanical method to obtain a mixture. The mixing device includes any type of device capable of forming a relatively homogeneous mixture, such as a known mixer agitator, and is not limited to a specific type of device. Meanwhile, in some aspects of the present disclosure, a heating process may be included to improve the dispersion of solids in the mixing process and to induce a fibrous form of the binder resin. In the heating process, the temperature may be appropriately controlled in the range of 30°C to 100°C.

[0064] Next, the mixture can be extracted into the shape of an anode (wide film shape) using an extruder, and a positive electrode active material layer can be formed by adjusting the thickness through a pressing process. The positive electrode active material layer may be applied to a positive electrode without a current collector, or, if necessary, a current collector may be attached to the obtained positive electrode active material layer to manufacture a positive electrode containing a current collector.

[0065] It should be noted that ball milling of only the S / LPSCl composite results in amorphous characteristics of sulfur, such as the broadening and reduction of the (222) main diffraction peak of sulfur. The addition of acetylene black carbon increases the amorphous characteristics within the composite. Fig. 9a is an XRD diffraction plot illustrating the amorphization of the complex for the milled S / LPSCl composite according to various milling times. As the milling time increases, the amorphization of sulfur in the S / LPSCl composite is evident. Fig. 9b is an XRD diffraction plot illustrating the amorphization of the complex for the milled S / LPSCl / C composite according to various milling times. The amorphous characteristics of sulfur can contribute to the improvement of the kinetics of the cathode composite by promoting faster lithium transport.

[0066] Since sulfide-containing materials are sensitive to air and moisture and can decompose to produce toxic gases such as H2S, according to some aspects of the present disclosure, all synthesis and testing steps are performed in a glove box filled with argon or a suitable device (e.g., MBraun MB 200B, H2O <0.5 ppm, O2 <5.0 ppm).

[0067] In a specific aspect, before milling, the weight ratio of sulfur particles, sulfur-containing solid electrolyte particles, and conductive material is 20-50:40-60:10-30. In one aspect, the sulfur particles, sulfur-containing solid electrolyte particles, and conductive material are in a weight ratio of 30:50:20, preferably 25:50:25 or 20:50:30.

[0068] Milling is preferably performed at 200-500 rpm, 300-500 rpm, 400-500 rpm, or 400 rpm.

[0069] In one aspect, milling may be performed for any time suitable for achieving the desired particle size. For example, milling may be performed for 30 minutes. In some aspects, the reaction time may be from 1 hour to 8 hours, and according to some aspects, from 2 hours to 7 hours or from 3 hours to 5 hours. Milling is preferably performed for 1 hour.

[0070] Next, the milled mixture is pressurized to form a composite anode. In a specific aspect, the pressurization is performed at a pressure of 100 MPa to 500 MPa, for example, 150 MPa to 375 MPa.

[0071] Pressurization can be performed for 1 to 60 minutes, for example, 10 minutes, 15 minutes, 30 minutes, 45 minutes, or 50 minutes.

[0072] In some aspects, sulfur has amorphous characteristics after ball milling.

[0073] In a specific aspect, the composite anode is composed of sulfur channels after electrochemical cycling, wherein the channel diameter may be in the range of 10 to 40 microns and is probabilistically distributed within the composite. The channel diameter may be 15 microns, 20 microns, 25 microns, or 30 microns.

[0074] Next, an anode (also called a cathode) can be manufactured using a composite anode mixture.

[0075] The positive current collector can be used in a battery to which the positive current collector is applied without particular limitation, as long as the positive current collector exhibits high conductivity without inducing any chemical changes. For example, the positive current collector may be made of stainless steel, aluminum, nickel, titanium, or calcined carbon. Alternatively, the positive current collector may be made of aluminum or stainless steel with a surface treated with carbon, nickel, titanium, or silver.

[0076] The current collector is not limited to a specific type and may include materials that do not cause chemical changes in the battery and have high conductivity (e.g., stainless steel, copper, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel with a surface treated with carbon, nickel, titanium, and silver).

[0077] According to the present disclosure, the positive electrode active material comprises surface-modified positive electrode active material particles for sulfide-based all-solid-state batteries. Additionally, additional materials may be used depending on the application of the lithium secondary battery. For example, transition metal compound-based active materials or sulfide-based active materials may be used.

[0078] All-solid-state battery

[0079] One aspect of the present disclosure relates to a solid-state battery comprising a solid electrolyte material as an electrolyte. Specific examples of the solid-state battery include any type of primary battery, secondary battery, fuel cell, solar cell, or capacitor such as a supercapacitor. In particular, the battery is a lithium-ion secondary battery. The aspects of the present disclosure may be implemented in secondary batteries having various form factors or battery formats, including, for example, pouch-type batteries, cylindrical-type batteries, or prismatic-type batteries.

[0080] In one aspect of the present disclosure, a solid-state battery according to the present disclosure comprises an anode (negative electrode), a cathode (positive electrode), and a solid electrolyte interposed between the negative electrode and the positive electrode.

[0081] The electrode of an all-solid-state battery may have a structure in which an electrode active material is formed on an electrode current collector. The electrode current collector may be omitted depending on the structure of the electrode. If the electrode is a negative electrode, the electrode current collector is a negative current collector.

[0082] In certain aspects, the all-solid-state battery is manufactured through a dry compression process in which electrode powder and solid electrolyte powder are prepared or introduced into a predetermined mold and compressed together with a polymer binder, or through a slurry coating process in which a slurry composition comprising an active material, a solvent, and a binder is prepared, coated onto a current collector, and dried. In the present disclosure, the method of manufacturing an all-solid-state battery having the above structure is not particularly limited. Any known method may be used.

[0083] For example, a solid electrolyte can be placed between the anode and the cathode, and then compressed to assemble the cell. After mounting the assembled cell inside an outer casing, the outer casing is sealed by heating and compression. As the outer casing, a laminated case made of aluminum or stainless steel, a cylindrical metal container, or a prismatic metal container may be suitably used.

[0084] The electrode slurry can be coated onto the current collector by placing the electrode slurry on the current collector and uniformly dispersing the electrode slurry using a doctor blade, die casting, comma coating, or screen printing method. Alternatively, the electrode slurry and the current collector may be formed on separate substrates and joined together through compression or lamination. In this case, the concentration of the slurry solution or the number of coatings may be adjusted to control the final coating thickness.

[0085] The drying process is a process of removing solvent or moisture from a slurry to dry the slurry coated on a metal current collector. The drying process may vary depending on the solvent used. For example, the drying process may be performed in a vacuum oven at a temperature of 50°C to 200°C. For example, drying may be performed using hot air drying, hot air drying, low-humidity air drying, vacuum drying, (far)infrared drying, or electron beam irradiation. The drying time is not particularly limited. Generally, drying is performed within a range of 30 seconds to 24 hours.

[0086] After the drying process, a cooling process may be additionally performed. In the cooling process, slow cooling to room temperature may be performed so that the recrystallized structure of the binder is sufficiently formed.

[0087] Additionally, if necessary, a rolling process may be performed after the drying process to increase the capacity density of the electrode and improve the adhesion between the current collector and the active material by passing the electrode through a gap between two heated rolls to compress the electrode to a desired thickness. In the present disclosure, the rolling process is not particularly limited. Known rolling processes, such as compression, may be performed. For example, the electrode may be passed through a gap between rotating rolls, or the electrode may be compressed using a flat press.

[0088] For the purpose of a solid electrolyte interposed between the negative and positive electrodes in an all-solid-state battery, any suitable sulfide-containing electrolyte material may be used. The term "sulfide-based electrolyte" used herein refers to an ion (e.g., Li + It refers to an electrolyte containing an S-containing inorganic material suitable for conducting ) and electrically insulating the anode and cathode of an electrochemical cell. An exemplary sulfide-containing electrolyte is described in the literature [Shaojie Chen et al ., " Sulfide solid electrolytes for all-solid-state lithium batteries: Structure, conductivity, stability and application ," Energy Storage Materials [It is described in Volume 14, Pages 58-74 (September 2018)], the entirety of which is expressly incorporated herein by reference.

[0089] For example, many sulfide-containing electrolyte materials (~10 -2 S cm -1 It is particularly attractive due to its high degree of superionic conductivity and deformability. In particular, Li3P7S 11 , Li 10 GeP2S 12 Na3PS4 and Li6PS5Cl have been reported to exhibit high ionic conductivity, some even approaching that of liquid electrolytes. According to aspects of the present disclosure, sulfide solid electrolyte materials also provide a low Young's modulus, which is beneficial for creating favorable interfacial contact with electrode materials by simple cold pressing at room temperature.

[0090] According to aspects of the present disclosure, a sulfide-containing solid electrolyte contains sulfur (S) and a metal belonging to Group I or Group II of the periodic table, for example, Li + It may have an ionic conductivity of . Additionally, in one aspect of the present disclosure, the selected solid electrolyte is 1 x 10⁻⁶ -5 S / cm, or 1x10 according to some aspects of the present disclosure -3 It has an ionic conductivity of S / cm or greater.

[0091] Non-limiting examples of sulfide-containing solid electrolytes include Li-PS-based glass, Li-PS-based glass ceramics, and azirodite-based sulfide-containing solid electrolytes.

[0092] Non-limiting examples of sulfide-containing solid electrolytes include at least one of xLi2S-yP2S5, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2O5, Li2S-P2S5-SiS2, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2 or Li2S-GeS2-ZnS, Li6PS5X (X = at least one of Cl, Br or I).

[0093] In one aspect of the present disclosure, the sulfide-containing solid electrolyte may comprise at least one selected from LPS-based glass or glass ceramic such as xLi2S-yP2S5, or a azirodite-based sulfide-containing solid electrolyte (Li6PS5X; X = Cl, Br, I).

[0094] In another aspect, the solid electrolyte may include solid electrolytes commonly used in all-solid-state batteries, and, for example, inorganic solid electrolytes or organic solid electrolytes may be used.

[0095] For inorganic solid electrolytes, ceramic materials, crystalline materials, or amorphous materials can be used. For example, thio-LISICON(Li 3.25 Ge 0.25 P 0.75 S4), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li2S-P2S5, Li3PS4, Li7P3S 11, Li2O-B2O3, Li2O-B2O3-P2O5, Li2O-V2O5-SiO2, Li2O-B2O3, Li3PO4, Li2O-Li2WO4-B2O3, LiPON, LiBON, Li2O-SiO2, LiI, Li3N, Li5La3Ta2O 12 , Li7La3Zr2O 12 , Li6BaLa2Ta2O 12 , Li3PO (4-3 / 2w) N w (where w is w<1), and Li 3.6 Si 0.6 P 0.4 Inorganic solid electrolytes such as O4 can be used.

[0096] The arithmetic mean size of the sulfide-based particles is, for example, 0.1 μm to 50 μm, preferably 0.5 μm to 20 μm, which is within the size range of sulfide-based particles used in known all-solid-state batteries. If the arithmetic mean size of the sulfide-based particles is smaller than the above range, the sulfide-based particles may form clumps. If the arithmetic mean size of the sulfide-based particles is larger than the above range, the porosity of the solid electrolyte being manufactured is high, which may degrade the characteristics of the battery. For example, the capacity of the battery may decrease.

[0097] Preferably, the sulfide-based particles are 1×10 -4 It has an ionic conductivity of S / cm or greater. More preferably, the sulfide-based particles are 1×10 -3 It has an ionic conductivity of S / cm or greater.

[0098] In addition to the aforementioned sulfide-based solid electrolytes, other known solid electrolytes may also be used. For example, Li2O-B2O3, Li2O-B2O 3- P2O5, Li2O-V2O5-SiO2, Li3PO4, Li2O-Li2WO4-B2O3, LiPON, LiBON, Li2O-SiO2, LiI, Li3N, Li5La3Ta2O 12 , Li7La3Zr2O 12 , Li6BaLa2Ta2O12 , Li3PO (4-3 / 2w) N w (w<1), or Li 3.6 Si 0.6 P 0.4 Inorganic solid electrolytes such as O4 can be used.

[0099] In addition, examples of organic solid electrolytes include organic solid electrolytes prepared by mixing lithium salts with polymeric materials such as polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, agitation lysine, polyester sulfide, polyvinyl alcohol, and polyvinylidene fluoride. In this case, these can be used alone or in combination of at least two.

[0100] The above-described coated sulfide-containing electrolyte material can be used as a solid electrolyte for an all-solid-state battery. An all-solid-state battery comprises a positive electrode and a negative electrode, with a solid electrolyte interposed between them.

[0101] Meanwhile, the positive and negative electrodes of the all-solid-state battery according to the aspects of the present disclosure are not particularly limited, and any suitable ones known in the art may be used.

[0102] The all-solid-state battery proposed according to the aspects of the present disclosure defines the composition of the solid electrolyte as described above, and other elements constituting the battery, namely the positive electrode and the negative electrode, are not specifically limited in the present disclosure and follow the description below.

[0103] In one aspect, the negative electrode of the all-solid-state battery may be lithium metal alone, or a negative electrode active material may be laminated on a negative electrode current collector.

[0104] The negative electrode current collector is not particularly limited as long as it is conductive and does not cause any chemical changes in the all-solid-state battery, and for example, copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel with a surface treated with carbon, nickel, titanium, silver, etc., or aluminum-cadmium alloy may be used. In addition, the negative electrode current collector, like the positive electrode current collector, may include various forms such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics with fine irregularities formed on their surfaces.

[0105] The negative electrode active material may be one or more of lithium metal, lithium alloy, lithium metal composite oxide, lithium-containing titanium composite oxide (LTO), and combinations thereof. In this case, the lithium alloy may be an alloy of lithium and at least one metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, and Sn. Additionally, the lithium metal composite oxide may be an oxide (MeO₂) of lithium and any one metal (Me) selected from the group consisting of Si, Sn, Zn, Mg, Cd, Ce, Ni, and Fe. x It can be ) and, for example, LixFe2O3 (0≤x≤1) or LixWO2 (0≤x≤1).

[0106] In addition, the negative electrode active material is Sn x Me 1-x Me y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of Groups 1, 2, and 3 of the periodic table, halogens; 0 <x=1; 1=y=3; 1=z=8)와 같은 금속 복합 산화물; SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O 4　It may include oxides such as Bi2O5; and carbon-containing cathode active materials such as crystalline carbon, amorphous carbon or carbon composites, and these may be used alone or in combination of two or more.

[0107] Additionally, the electrode may contain a conductive agent, a solid electrolyte, or a dispersant in addition to the active material. As the conductive agent, nickel powder, cobalt oxide, titanium oxide, or carbon may be used. As the carbon, at least one selected from the group consisting of Ketjen black, acetylene black, furnace black, graphite, carbon fiber, and fullerene may be used.

[0108] Form for carrying out the invention

[0109] Examples

[0110] The following examples are not intended to be limiting. The above disclosure provides many different aspects for implementing the features of the present disclosure, and the following examples describe specific aspects. It will be understood that other variations and methods known to those skilled in the art may also be applied to the following experimental procedures without departing from the scope of the present disclosure.

[0111] Synthesis Example 1 - Composite Anode

[0112] Milled sulfur was produced by milling sulfur (1 g batch, Sigma Aldrich) with 5 mm balls at 400 rpm for 10 hours using an Emax high-power mill.

[0113] Li1In1 was synthesized by combining 60 mg of Li SLMP (Livent) and 990 mg of indium metal powder (Fisher Scientific) (-100 mesh). The mixture was vortex mixed for 5 minutes.

[0114] The anode material was synthesized by combining the above-mentioned milled sulfur, LPSCl, and acetylene black (AB) carbon (Sigma-Aldrich) in a weight ratio of 30:50:20 to form a milled anode. A 1g batch was milled with a 5mm ball at 500rpm for 1 hour.

[0115] The anode material was chemically stable and no new bulk phase was present. In the PXRD diffraction and Raman spectra of Figures 1a and 1b, it can be seen that peaks (lower curves) that exist individually for LPSCl and sulfur, respectively, are present together in the mixture of LPSCl and sulfur. The upper curves of Figures 1a and 1b represent a mixture of LPSCl, sulfur, and acetylene black (AB). Figure 2a shows an SEM image of ball-milled sulfur, Figure 2b shows an SEM image of milled LPSCl, and Figure 2c shows an SEM image of the anode mixture of LPSCl, sulfur, and acetylene black (AB).

[0116] A composite anode was formed by applying pressure of 375 MPa to the milled anode material for 5 minutes.

[0117] Experimental Example 1

[0118] The milled anode material from Synthesis Example 1, using a fixed gap holder as shown in FIG. 4a, 5 mAh cm -2 , Li1In1 available capacity 110mAh g -1 and the area capacity performance was tested at an NP ratio of 2.

[0119] Fig. 3a shows a design area capacity of 1.6 mAh cm² -2 Voltage in the case of vs. Li + Capacity as a function of / Li(V) (mAh g -1 The test results for ) are plotted, where the first cycle is 0.07 mA cm -2 Tested at, and the second cycle at a higher current density of 0.8 mA cm -2 Tested at. Figure 3b is 0.8 mA cm-2 Specific capacity as a function of the number of cycles when operating (mAh g -1 Figures 3a and 3b illustrate the results for ). Figures 3a and 3b demonstrate the high-rate cycling performance obtained using the milled anode material. There was excellent retention and stable cycling at high rates, and a capacity retention rate of 95.5% was achieved after 485 cycles.

[0120] Fig. 4a shows the device used for testing, with 5 mAh cm⁻¹. -2 , Li1In1 available capacity 110mAh g -1 and illustrates a device that is a fixed gap holder with an NP ratio of 2. FIG. 4b shows voltage vs. Li + S capacity (mAh g) as a function of / Li(V) -1 Figure 4c illustrates the results for ). S capacity (mAh g) as a function of the number of cycles. -1 The results for ). As can be seen, the C / 2 performance is 2.8mA cm⁻¹, exceeding that of the Li1In1CCD. -2 It was unstable at, and the C / 5 performance was 1.12 mA cm -2 It was stable. When the area load is high, the limiting factor appears to be the anode.

[0121] Experimental Example 2

[0122] The setup was performed at a constant pressure of 10 MPa as shown in Fig. 5a (reference [S.-Y. Ham e t al ., Energy Storage Materials According to 55:455-462 (2023)), anode area capacity of 1.6-5 mAh cm² -2 The performance in this case was evaluated. LPSCl was used as the electrolyte, a milled cathode mixture of sulfur, LPSCl, and acetylene black (AB) carbon in a weight ratio of 30:50:20 from Synthesis Example 1 was used as the cathode material, and Li metal was used as the anode. Each had a performance of 1.6 mAh cm⁻¹. -2 and 5mAh cm -2Voltage vs. Li when tested + S capacity (mAh g) as a function of / Li(V) -1 The results for ) are shown in Figs. 5b and 5c.

[0123] Using the same setup as shown in FIG. 5a, the capacity S (mAh g) as a function of the number of cycles -1 The results for ) are shown in Figs. 6a and 6b, respectively. Fig. 6a is 1.6 mAh cm⁻¹ -2 S capacity (mAh g) as a function of the number of cycles when evaluated -1 Figure 6b illustrates the results for ). Figure 6b is 5 mAh cm -2 S capacity (mAh g) as a function of the number of cycles when evaluated -1 Displays the results for ).

[0124] Experimental Example 3

[0125] The procedure described in Experimental Example 1 was performed, but using setups for two additional chloride-based solid electrolytes, e.g., LZC (Li2ZrCl6) and LYC (Li3YCl6), respectively. Figures 7a–7f illustrate the test results for the performance of elemental sulfur all-solid-state cells using chloride and sulfide-based electrolytes. The voltage profiles and cycling performance of LZC (see Figures 7a and 7b), LYC (see Figures 7c and 7d), and LPSCl (see Figures 7e and 7f) as ion conductors within the anode complex are shown. The LPSCl solid electrolyte remains an ideal choice because it exhibits reversibility within the operating voltage range of 1–3 V for sulfur redox with respect to Li / Li+. While chloride electrolytes achieve sufficient capacity utilization, their stability is lower due to a higher reduction potential, which reduces the ion conductivity within the anode complex.

[0126] Comparative Example 1

[0127] Setup with a constant pressure of 10MPa and 1.6mAh cm -2The anode area capacity was as shown in Fig. 5a. LPSCl was used as the electrolyte, and a mixture of sulfur, LPSCl, and acetylene black (AB) carbon in a weight ratio of 30:50:20 was used as the anode material, provided that the mixture was not ball-milled as shown in Fig. 7g and compared with the results of the milled anode shown in Fig. 7e. In both cases, Li1In1 was used as the cathode.

[0128] It will be understood by those skilled in the art that aspects of this disclosure may be practiced within a broad range of equivalent parameters without affecting the scope of the disclosure described herein. All publications, patent applications, and patents disclosed herein are incorporated by reference in their entirety.

Claims

Claim 1 As a composite cathode, the composite cathode comprises: a plurality of sulfur particles having an arithmetic mean particle size of 5 μm to 10 μm; a plurality of sulfur-containing solid electrolyte particles represented by the formula Li6PS5X (wherein X = Cl, Br, or I); and a conductive material comprising a plurality of acetylene black carbon particles, wherein the plurality of acetylene black carbon particles have a mean particle size of 10 nm to 100 nm and a BET specific surface area of ​​50 m² 2 g -1 up to 150m 2 g -1 A composite anode having a para-crystalline structure; ball-milling the plurality of sulfur particles, the plurality of sulfur-containing solid electrolyte particles, and the conductive material to form a milled mixture; and pressurizing the milled mixture. Claim 2 A composite anode according to claim 1, wherein the weight ratio of the plurality of sulfur particles, the plurality of sulfur-containing solid electrolyte particles, and the conductive material is 20-50 : 40-60 : 10-30. Claim 3 In claim 1, the plurality of acetylene black carbon particles are non-porous composite anodes. Claim 4 In claim 1, the plurality of acetylene black carbon particles have a BET specific surface area of ​​75 m² 2 g -1 to 125 m 2 g -1 Phosphorus composite anode. Claim 5 A step of providing a plurality of sulfur particles having an arithmetic mean particle size of 5 μm to 10 μm; a step of providing a plurality of sulfur-containing solid electrolyte particles represented by the formula Li6PS5X (wherein X = Cl, Br, or I); and a conductive material comprising a plurality of acetylene black carbon particles, wherein the plurality of acetylene black carbon particles have an average particle size of 10 nm to 100 nm and a BET specific surface area of ​​50 m² 2 g -1 up to 150m 2 g -1 A method for manufacturing a composite anode, comprising: a step of providing a conductive material having a quasicrystalline structure; a step of milling the plurality of sulfur particles, the plurality of sulfur-containing solid electrolyte particles, and the conductive material to form a milled mixture; and a step of pressurizing the milled mixture to form a composite anode. Claim 6 In claim 5, the milling is performed at 200-500 rpm. Claim 7 In claim 5, the milling is performed at 400-500 rpm. Claim 8 In paragraph 5, the above milling is performed for one hour. Claim 9 In paragraph 5, the above pressurization is performed at a pressure of 100 MPa to 500 MPa. Claim 10 In paragraph 5, the above pressurization is performed for 1 minute to 60 minutes. Claim 11 A method according to claim 5, wherein the weight ratio of the plurality of sulfur particles, the plurality of sulfur-containing solid electrolyte particles, and the conductive material is 20-50 : 40-60 : 10-30. Claim 12 In claim 5, the plurality of acetylene black carbon particles are a method in which the average particle size is 40 nm. Claim 13 In claim 5, the plurality of acetylene black carbon particles have a BET specific surface area of ​​90 m² 2 g -1 The method. Claim 14 In paragraph 5, the plurality of acetylene black carbon particles are non-porous. Claim 15 In paragraph 5, the method wherein the plurality of acetylene black carbons have a quasicrystalline structure. Claim 16 A composite anode manufactured according to the method of paragraph 5. Claim 17 A cathode; a composite anode according to claim 1; and an all-solid-state battery comprising a solid electrolyte. Claim 18 In claim 17, the composite anode is an all-solid-state battery comprising a sulfur channel in contact with the solid electrolyte. Claim 19 In claim 18, the sulfur channel is an all-solid-state battery having a channel diameter in the range of 10 microns to 40 microns. Claim 20 A composite anode comprising amorphous sulfur in claim 1.

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