Composite positive electrode for all-solid-state battery, manufacturing method therefor, and all-solid-state battery thereof

Abstract

A composite positive electrode, a composite positive electrode manufacturing method, and an all-solid-state battery comprising the composite positive electrode are disclosed. The composite positive electrode comprises: a plurality of sulfur particles with an arithmetic average particle size of 5-10 μm; a plurality of sulfur-containing solid electrolyte particles of formula Li6PS5X (here, X is 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 10-100 nm and a BET specific surface area of 50 m2g-1 to 150 m2g-1, and have a quasi-crystalline structure. The sulfur particles, the sulfur-containing solid electrolyte particles and the conductive material are ball-milled to form a milled mixture, and are pressed to form a composite positive electrode.

Description

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

[0001] Cross-reference to related applications

[0002] This application claims the benefit of priority to 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. Non-Provisional Application No. 18 / 778,467, filed July 19, 2024, the entire contents of which are expressly incorporated herein by reference in their 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. Also described are an all-solid-state battery comprising the composite positive electrode, and a method for manufacturing the composite positive electrode and battery.

[0005] The rise of electrified transportation continues, exemplified by the widespread adoption of electric vehicles (EVs) and the emergence of urban air mobility (UAM) vehicles. Simultaneously, demand for stationary energy storage systems powered by solar and wind power is growing, particularly in the residential and industrial sectors. This shift is driven in part by the urgent need to mitigate the environmental and climate impacts associated with traditional internal combustion engines and other non-renewable power sources. Consequently, the development of battery technologies that offer high energy density while also ensuring enhanced safety has become essential.

[0006] Conventional liquid lithium-ion batteries have been instrumental in the development of electric transportation 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 also have certain limitations. For example, various safety mechanisms are essential in lithium-ion batteries to limit voltage and internal pressure, but these safety features typically result in increased weight and, in certain cases, limited performance. Furthermore, lithium-ion batteries are susceptible to aging, losing capacity and ultimately failing after years of use.

[0007] All-solid-state batteries (ASSBs) utilize a solid electrolyte instead of a liquid one, making the entire battery solid. Solid electrolytes are inherently non-flammable and can withstand a wider temperature range, allowing them to function as electrochemical energy storage devices without the need for additional safety devices. Solid-state batteries offer higher energy densities and are safer than conventional batteries with liquid electrolyte systems, such as lithium-ion batteries. In conventional solid-state batteries, the replacement of liquid electrolytes with solid electrolytes reduces the risk of fire or explosion, thereby enhancing safety.

[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 -1) is significantly higher than other battery systems, and sulfur is attracting attention as a portable electronic device due to its abundant resources, cheapness, and eco-friendliness. Lithium metal is advantageous because it is lightweight and can potentially implement high energy density, and various positive electrode active materials, such as sulfur-containing positive electrode active materials with sulfur-sulfur bonds, can be used in lithium batteries, which have high energy capacity due to the 16-electron conversion reaction that forms Li2S in a reduced state. However, when sulfur is used as a positive electrode active material in a lithium-sulfur battery, it is difficult for electrons and lithium ions generated by the electrochemical reaction to move because sulfur is a non-conductor. In addition, in the case of a sulfur positive electrode, there is a problem that performance and lifespan are reduced because the volume change during charge and discharge is large.

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

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

[0011] The composite cathode 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 (wherein X = Cl, Br, or I); and (iii) a mean particle size of 10 nm to 100 nm and a Brunauer-Emmett-Teller (BET) surface area of ​​50 m 2 g -1 150m inland 2 g -1 , and 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 pressing.

[0012] Some aspects provide a plurality of sulfur particles having an arithmetic mean particle size of 5 μm to 10 μm; providing a plurality of sulfur-containing solid electrolyte particles of the formula Li6PS5X (wherein X = Cl, Br, or I); having an average particle size of 10 nm to 100 nm and a BET specific surface area of ​​50 m 2 g -1 150m inland 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 quasi-crystal structure; milling the sulfur particles, sulfur-containing solid electrolyte particles, and a conductive material to form a milled mixture; and pressing the milled mixture to form a composite anode. Some aspects relate to a composite anode manufactured according to the 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] Certain aspects relate to an all-solid-state battery comprising a cathode; a composite cathode as described herein; and a solid electrolyte. Preferably, the composite cathode comprises sulfur channels in contact with the solid electrolyte. Such sulfur channels may have a channel diameter in the range of 10-40 microns.

[0017] Some aspects relate to composite anodes comprising 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, the plurality of sulfur-containing solid electrolyte particles are of the formula Li6PS5Cl.

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

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

[0022] In some respects, the plurality of acetylene black carbon particles are nonporous.

[0023] In some respects, the plurality of acetylene black carbons have a quasi-crystalline structure.

[0024] Each side may have one or more additional elements in any combination.

[0025] The accompanying drawings illustrate aspects of the present disclosure and, together with the detailed description, serve to further understand the technical concepts of the present disclosure, and the present disclosure should not be construed as being limited to the drawings. In the drawings, the shape, size, scale, or proportion of elements may be exaggerated for clarity of explanation.

[0026] Figures 1a and 1b show the PXRD diffractogram and Raman spectrum for the milled cathode material of Synthesis Example 1.

[0027] 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 a cathode mixture of LPSCl, sulfur, and acetylene black (AB).

[0028] Figure 3a is 1.6 mAh g -1 Voltage vs. Li when operated at + Capacity (mAh g) as a function of / Li(V) -1 ) shows the test results for 1.6 mAh g. Figure 3b shows the test results for 1.6 mAh g -1 Specific capacity (mAh g) as a function of cycle number when operated at -1 ) shows the results.

[0029] Figure 4a shows the device used for testing, 5 mAh cm -2 , Li1In1 available capacity 110mAh g -1 and a device with a fixed gap holder of NP ratio 2. Figure 4b shows voltage vs. Li + S capacity (mAh g) as a function of / Li(V) -1 ) is shown. Figure 4c shows the S capacity (mAh g) as a function of the number of cycles. -1 ) shows the results.

[0030] Figure 5a shows a constant pressure of 10 MPa, 1.6-5 mAh cm -2 The experimental setup used (according to the literature [S.-Y. Hamet al., Energy Storage Materials 55:455-462 (2023)]) is shown in Fig. 5b. Voltage vs. Li + S capacity (mAh g) as a function of / Li(V) -1 ) about 1.6mAh cm -2 The results of Experimental Example 1 when tested in Fig. 5c are shown in the voltage vs. Li + S capacity (mAh g) as a function of / Li(V) -1 ) about 5mAh cm -2The results of Experimental Example 1 when tested in are shown.

[0031] Figure 6a is 1.6 mAh cm -2 S capacity (mAh g) as a function of cycle number when measured in -1 ) is shown. Figure 6b shows the results for 5 mAh cm -2 S capacity (mAh g) as a function of cycle number when measured in -1 ) shows the results.

[0032] Figures 7a-f illustrate the test results for elemental sulfur all-solid-state cell performance 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) when used as an ionic conductor in a cathode composite are shown. Figure 7g illustrates a comparison of the results with the milled cathode shown in Figure 7e.

[0033] Figure 8a shows an SEM image and EDS mapping of the surface of a pristine μm sulfur composite electrode. Figure 8b shows an SEM image and EDS mapping of the surface of a cycled μm sulfur composite electrode.

[0034] Figure 9a is an XRD diffractogram illustrating the complex amorphization for milled S / LPSCl composites at various milling times. As the milling time increases, the sulfur amorphization in the S / LPSCl composite is evident. Figure 9b is an XRD diffractogram illustrating the complex amorphization for milled S / LPSCl / C composites at various milling times.

[0035] Figure 10a demonstrates the size effect of LPSCl solid electrolyte on the first cycle voltage profile comparing micronized and uncapped LPSCl at 5 mAh cm. -2Electrochemical performance in areal capacity is shown. Figure 10b shows SEM images of micron and non-micronized LPSCl solid electrolytes.

[0036] Hereinafter, the present disclosure will be described in detail. It should be understood that the terms and words used in this specification and the appended claims should not be construed as limited to their ordinary or dictionary meanings, but rather should be construed based on meanings and concepts consistent with the technical spirit of the present disclosure, based on the principle that the inventor can appropriately define terms for the best explanation. Therefore, it should be understood that the aspects of the present disclosure described herein and the elements depicted in the drawings are only aspects of the present disclosure and do not completely represent the technical spirit of the present disclosure, and that other equivalents and variations may exist at the time of filing this application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly known to those skilled in the art. If there are multiple definitions for a term in this application, the definitions provided herein shall take precedence.

[0037] Unless otherwise stated, all percentages, parts and ratios in this disclosure are by weight.

[0038] Unless otherwise indicated, the numerical parameters set forth in the specification and attached claims below are approximations that may vary depending upon the desired properties sought to be obtained in accordance with aspects of the present disclosure. Whenever a numerical range having a lower and an upper limit is disclosed, any number falling within that range and any subsumed range are specifically disclosed. In particular, any range of values ​​disclosed herein (in the form "from about a to about b," or, equivalently, "from about a to b," or, equivalently, "about ab") should be understood to describe all numbers and ranges subsumed within the broader range of values.

[0039] Although compositions and methods are described herein as "comprising" various components or steps, it is also possible for the compositions and methods to "consist essentially of" or "consist of" the various components and steps. The term "comprises" as used herein specifies the presence of the stated elements, but does not exclude the presence or addition of one or more other elements, unless the context clearly dictates otherwise.

[0040] The terms "about" and "substantially" are used herein to mean at or near the numerical value when manufacturing and material tolerances inherent in the circumstances are given, and are used to prevent unscrupulous infringers from unfairly taking advantage of the disclosure when precise or absolute values ​​are mentioned to facilitate understanding of the disclosure. The terms "about" and "approximately" used with a numerical variable generally mean the value of that variable, and any value of that variable within experimental error (e.g., a 95% confidence interval for the mean) or within ±10% of the stated value or within a wider range. Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weights, reaction conditions, and the like used in this specification and any related claims are to be understood as being modified by the term "about."

[0041] As used herein, “A and / or B” specifies “A or B or both.”

[0042] The term "arithmetic mean particle size" as used herein means the particle size obtained by the arithmetic mean observed using a scanning electron microscope (SEM).

[0043] The term "mean particle size" as used herein refers to the average particle size observed using SEM.

[0044] Composite bipolar

[0045] 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, which is then pressurized to form the composite anode.

[0046] Another aspect concerns the method for manufacturing composite anodes.

[0047] Another aspect relates to an all-solid-state battery comprising an anode; the aforementioned composite anode; 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 pose a combustion risk).

[0048] In some aspects, the composite anode comprises sulfur channels in contact with the solid electrolyte. These sulfur channels may be randomly distributed within the anode composite with channel diameters ranging from 10 to 40 microns, as illustrated in FIG. 8b.

[0049] As discussed below, the positive electrode can be manufactured by providing a plurality of sulfur particles having an arithmetic mean particle size of 5 μm to 10 μm; providing a plurality of sulfur-containing solid electrolyte particles of the formula Li6PS5X (wherein X = Cl, Br, or I); and providing 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 m 2 g -1 150m inland 2 g -1 , and has a quasi-crystalline structure. The sulfur particles, sulfur-containing solid electrolyte particles, and conductive material are milled to form a milled mixture. The milled mixture is pressurized to form a composite anode.

[0050] The arithmetic mean particle size of the sulfur particles used to manufacture the composite anode may be from 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.

[0051] The sulfur particles can be used as received in commercial form.

[0052] The sulfur particles may be individually milled prior to combining with the sulfur-containing solid electrolyte particles and acetylene black carbon particles.

[0053] 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 lithium sulfide is used, 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 form and anhydrous form. When lithium sulfide particles are used, they are preferably in the micron scale, for example, 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 preserved after ball milling (e.g., ball milling at 500 rpm for 1 hour). For example, the lithium sulfide particles, sulfide-based solid electrolyte (LPSCl), and conductive material are ball milled in the same manner as discussed below for sulfur particles, and then pressed to form the positive electrode. For lithium sulfide particles, 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 wt%.

[0054] The sulfur-containing solid electrolyte particles are preferably of the formula Li6PS5X (wherein X = Cl, Br, or I). In one aspect, the plurality of sulfur-containing solid electrolyte particles are of the formula Li6PS5Cl.

[0055] In certain aspects, the arithmetic mean particle size of the sulfur-containing solid electrolyte particles is 5-10 μm. The arithmetic mean particle size of the sulfur particles may have a lower limit of 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 arithmetic mean particle size of the sulfur particles may have an upper limit of 9.5 μm, 9 μm, 8.5 μm, 8 μm, 7.5 μm, 7 μm, 6.5 μm, 6 μm or 5.5 μm.

[0056] Figure 10a demonstrates the size effect of LPSCl solid electrolyte on the first cycle voltage profile comparing micronized and uncapped LPSCl at 5 mAh cm. -2 Electrochemical performance in areal capacity is shown. Figure 10b shows SEM images of micron and non-micronized LPSCl solid electrolytes.

[0057] 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.

[0058] Acetylene black carbon particles preferably have a BET surface area of ​​50 m 2 g -1 150m inland 2 g -1 , 75m 2 g -1 125m inland 2 g -1 , 80m 2 g -1 100m inland 2 g -1 or 90m 2 g -1 am.

[0059] The acetylene black carbon particles may preferably have a crystal structure. The crystal structure may include a continuous crystal structure, for example, single-crystal acetylene black carbon. Alternatively, the acetylene black carbon may include one or more crystal grains in a continuous crystal structure, for example, polycrystalline or multi-crystalline silicon.

[0060] In certain aspects, many acetylene black carbons have a quasi-crystalline structure that is neither completely amorphous nor completely crystalline. In a quasi-crystalline material, the acetylene black carbon exhibits short-range and / or medium-range order in its crystal structure, but lacks long-range order in at least one direction.

[0061] In certain aspects, acetylene black carbon particles are nonporous.

[0062] In certain aspects, the positive electrode may further comprise additional positive electrode active material, or optionally, additional electrically conductive material to facilitate movement of electrons in the positive electrode, and / or a binder to attach the positive electrode active material to the current collector.

[0063] For example, the additional anode conductive material may be at least one conductive material selected from the group consisting of graphite, carbon black, carbon fibers, carbon nanotubes, or metal fibers, metal powders, conductive whiskers, conductive metal oxides, activated carbon, or polyphenylene derivatives.

[0064] The additional conductive material is not particularly limited, and conductive materials such as graphite-based materials such as KS6, carbon-containing materials such as Super-p, Denka black, and carbon black, or conductive polymers such as polyaniline, polythiophene, polyacetylene, and polypyrrole may be used alone or in combination. 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.

[0065] Optionally, a binder may be used in the positive electrode. The binder may be added in an amount of 0.5 to 30 wt% based on the total weight of the mixture including the positive electrode active material. If the binder content is less than 0.5 wt%, the physical properties of the positive electrode may deteriorate, leading to loss of the active material and conductive material within the positive electrode. If the binder content exceeds 30 wt%, the ratio of the active material and conductive material within the positive electrode may relatively decrease, resulting in a decrease in battery capacity, which is not preferable.

[0066] As the above binder, 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, a copolymer of polyhexafluoropropylene and polyvinylidene fluoride (trade name: Kynar), poly(ethyl acrylate), polytetrafluoroethylene, polyvinyl chloride, polyacrylonitrile, polyvinylpyridine, polystyrene, derivatives, blends and copolymers thereof.

[0067] For example, the positive electrode binder resin may include a positive electrode polymer generally used in the relevant technical field. Non-limiting examples of the binder resin include, but are not limited to, polyvinylidene difluoride, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate, polyethylhexyl acrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, and carboxyl methyl cellulose.

[0068] Meanwhile, in some aspects of the present disclosure, the positive electrode has a capacity of 5 mAh / cm 2 Above, 6mAh / cm 2 or 10 mAh / cm 2 The battery according to the present disclosure can have a load (per anode area) above. When a high-load anode is applied, it is possible to operate the battery at an electrochemically stable level.

[0069] In a specific aspect, sulfur particles, sulfur-containing solid electrolyte particles, and a conductive material are ball milled to form a milled mixture.

[0070] The present disclosure utilizes a single-step fabrication method via ball milling, which is a simple and convenient method that avoids complex processes such as conventional multi-step methods or sulfur deposition on a solid electrolyte / carbon composite. It should be noted that the deposition technique cannot create a 3D structure, limiting the transport pathways to the solid electrolyte surface. As shown in Figures 8a and 8b, after cycling, sulfur channels that maintain good contact with the solid electrolyte are observed, which enhances the excellent performance. Figure 8a shows an SEM image and EDS mapping of the surface of an untreated μm sulfur composite anode. Figure 8b shows an SEM image and EDS mapping of the surface of a cycled μm sulfur composite anode.

[0071] The composite anode can be prepared 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 embodiments, 5 mm balls can be used for milling. In some embodiments, 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.

[0072] Mixing may also be performed using a dry mixing method. First, the positive electrode material, including the positive electrode active material, the conductive material, and the binder resin, is placed in a mixing device and mechanically mixed to obtain a mixture. The mixing device may include any type of device capable of forming a relatively homogeneous mixture phase, such as a known mixer or agitator, and is not limited to a specific type of device. Meanwhile, in some aspects of the present disclosure, a temperature raising process may be included to improve the dispersion of the solids in the mixing process and induce a fibrous form of the binder resin. In the temperature raising process, the temperature may be appropriately controlled within a range of 30°C to 100°C.

[0073] Next, the mixture is extruded into a positive electrode shape (a wide film shape) using an extruder, and the thickness can be controlled through a pressing process to form a positive electrode active material layer. The positive electrode active material layer can be applied to a positive electrode without a current collector, or, if necessary, a current collector can be attached to the obtained positive electrode active material layer to manufacture a positive electrode including a current collector.

[0074] Note that ball milling of the S / LPSCl composite alone results in amorphous sulfur characteristics, such as peak broadening and reduction of the (222) primary diffraction peak. The addition of acetylene black carbon increases the amorphous characteristics within the composite. Figure 9a is an XRD diffractogram showing composite amorphization for milled S / LPSCl composites at various milling times. As the milling time increases, sulfur amorphization in the S / LPSCl composite is evident. Figure 9b is an XRD diffractogram showing composite amorphization for milled S / LPSCl / C composites at various milling times. The amorphous sulfur characteristics may contribute to improved kinetics of the cathode composite by promoting faster lithium transport.

[0075] 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 an argon-filled glove box or a suitable apparatus (e.g., MBraun MB 200B, H2O <0.5 ppm, O2 <5.0 ppm).

[0076] In a specific aspect, before milling, the weight ratio of the sulfur particles, the sulfur-containing solid electrolyte particles, and the conductive material is 20-50:40-60:10-30. In one aspect, the sulfur particles, the sulfur-containing solid electrolyte particles, and the conductive material are in a weight ratio of 30:50:20, preferably in a weight ratio of 25:50:25 or in a weight ratio of 20:50:30.

[0077] Milling is preferably performed at 200-500 rpm, 300-500 rpm, 400-500 rpm, or 400 rpm.

[0078] In one aspect, milling can be performed for any time suitable to achieve the desired particle size. For example, milling can be performed for 30 minutes. In some aspects, the reaction time can be from 1 hour to 8 hours, and in some aspects, from 2 hours to 7 hours or from 3 hours to 5 hours. Milling is preferably performed for 1 hour.

[0079] Next, the milled mixture is pressed to form a composite anode. In certain aspects, the pressing is performed at a pressure of 100 MPa to 500 MPa, for example, 150 MPa to 375 MPa.

[0080] Pressurization can be performed for 1 to 60 minutes, for example 10 minutes, 15 minutes, 30 minutes, 45 minutes, or 50 minutes.

[0081] In some aspects, the sulfur has amorphous characteristics after ball milling.

[0082] In certain aspects, the composite anode is formed of sulfur channels after electrochemical cycling, wherein the channel diameter may range from 10 to 40 microns and is randomly distributed within the composite. The channel diameter may be 15 microns, 20 microns, 25 microns, or 30 microns.

[0083] Next, the anode (also called cathode) can be manufactured using the composite anode mixture.

[0084] The cathode current collector can be used without particular limitations as long as it exhibits high conductivity and does not induce any chemical change in the battery to which it is applied. For example, the cathode current collector may be made of stainless steel, aluminum, nickel, titanium, or calcined carbon. Alternatively, the cathode current collector may be made of aluminum or stainless steel whose surface is treated with carbon, nickel, titanium, or silver.

[0085] The current collector is not limited to a specific type and may include any material that does not cause a chemical change in the battery and has high conductivity (e.g., stainless steel, copper, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel whose surface is treated with carbon, nickel, titanium, and silver).

[0086] According to the present disclosure, the cathode active material comprises surface-modified, superior cathode active material particles for a sulfide-based all-solid-state battery. Additionally, additional materials may be used depending on the intended use of the lithium secondary battery. For example, transition metal compound-based active materials or sulfide-based active materials may be used.

[0087] All-solid-state battery

[0088] 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. Aspects of the present disclosure can be implemented in secondary batteries having various form factors or battery formats, including, for example, pouch-type batteries, cylindrical batteries, or prismatic batteries.

[0089] In one aspect of the present disclosure, a solid-state battery according to the present disclosure includes an anode, a cathode, and a solid electrolyte interposed between the cathode and the anode.

[0090] 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 electrode current collector.

[0091] In certain aspects, the all-solid-state battery is manufactured through a dry compression process in which electrode powder and solid electrolyte powder are manufactured or introduced into a predetermined mold together with a polymer binder and compressed, or a slurry coating process in which a slurry composition including an active material, a solvent, and a binder is manufactured, coated on a current collector, and dried. In the present disclosure, the method for manufacturing the all-solid-state battery having the above structure is not particularly limited. Any known method can be used.

[0092] For example, a solid electrolyte can be placed between the anode and cathode, and then compressed to assemble the cell. The assembled cell is then mounted within an outer member, which is then sealed by heating and compression. Suitable outer members include laminated cases made of aluminum or stainless steel, cylindrical metal containers, or prismatic metal containers.

[0093] 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. Alternatively, the electrode slurry and current collector can be formed on separate substrates and bonded to each other by pressing or laminating. At this time, the concentration of the slurry solution or the number of coatings can be adjusted to control the final coating thickness.

[0094] The drying process is a process of removing solvent or moisture from the slurry to dry the slurry coated on the 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 a warm air drying method, a hot air drying method, a low-humidity air drying method, a vacuum drying method, a (far) infrared drying method, or an electron beam irradiation method. The drying time is not particularly limited. Typically, drying is performed within a range of 30 seconds to 24 hours.

[0095] After the drying process, a cooling process may be additionally performed. In the cooling process, slow cooling to room temperature may be performed to sufficiently form a recrystallized structure of the binder.

[0096] 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, thereby compressing the electrode to a desired thickness by passing the electrode through a gap between two heated rolls. In the present disclosure, the rolling process is not particularly limited. A well-known rolling process such as pressing may be performed. For example, the electrode may be passed through a gap between rotating rolls, or the electrode may be pressed using a flat press.

[0097] For the purpose of a solid electrolyte interposed between the negative electrode and the positive electrode in an all-solid-state battery, any suitable sulfide-containing electrolyte material can be used. The "sulfide-based electrolyte" used herein means an electrolyte containing ions (e.g., Li + ) and electrically insulate the positive and negative electrodes of the electrochemical cell. Exemplary sulfide-containing electrolytes are described in the literature [Shaojie Chenet al., "Sulfide solid electrolytes for all-solid-state lithium batteries: Structure, conductivity, stability and application," Energy Storage Materials, Volume 14, Pages 58-74 (September 2018), which is expressly incorporated herein by reference in its entirety.

[0098] For example, many sulfide-containing electrolyte materials have (~10 -2 S cm -1 It is particularly attractive due to its high superionic conductivity and deformability. In particular, Li3P7S 11 , Li 10 GeP2S 12 , and Na3PS4 and Li6PS5Cl have been reported to exhibit high ionic conductivities, some even approaching those of liquid electrolytes. According to aspects of the present disclosure, the 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.

[0099] According to aspects of the present disclosure, a sulfide-containing solid electrolyte contains sulfur (S) and a metal belonging to group I or II of the periodic table, for example, Li. +may have an ionic conductivity of 1x10. Additionally, in one aspect of the present disclosure, the selected solid electrolyte may have an ionic conductivity of 1x10 -5 S / cm, or according to some aspects of the present disclosure 1x10 -3 It has an ionic conductivity of more than S / cm.

[0100] Non-limiting examples of sulfide-containing solid electrolytes include Li-PS-based glasses, Li-PS-based glass ceramics, and argyrodite-based sulfide-containing solid electrolytes.

[0101] 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 (wherein X = at least one of Cl, Br or I).

[0102] In one aspect of the present disclosure, the sulfide-containing solid electrolyte may include at least one selected from an LPS-based glass or glass ceramic such as xLi2S-yP2S5, or an argyrodite-based sulfide-containing solid electrolyte (Li6PS5X; X = Cl, Br, I).

[0103] In another aspect, the solid electrolyte may include a solid electrolyte commonly used in all-solid-state batteries, and for example, an inorganic solid electrolyte or an organic solid electrolyte may be used.

[0104] 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 0.75S4), 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.

[0105] The arithmetic mean size of the sulfide particles is, for example, 0.1 μm to 50 μm, preferably 0.5 μm to 20 μm, which is within the size range of the sulfide particles used in known all-solid-state batteries. If the arithmetic mean size of the sulfide particles is smaller than the above range, the sulfide particles may form lumps. If the arithmetic mean size of the sulfide particles is larger than the above range, the porosity of the solid electrolyte produced may increase, which may deteriorate the characteristics of the battery. For example, the capacity of the battery may decrease.

[0106] Preferably, the sulfide particles are 1×10 -4 It has an ionic conductivity of 1×10 S / cm or more. More preferably, the sulfide particles have an ionic conductivity of 1×10 -3 It has an ionic conductivity of more than S / cm.

[0107] 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 , Li6BaLa2Ta2O 12 , 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.

[0108] In addition, examples of organic solid electrolytes include organic solid electrolytes prepared by mixing lithium salts with polymer materials such as polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, agitated lysine, polyester sulfide, polyvinyl alcohol, and polyvinylidene fluoride. In this case, these may be used alone or in combination of at least two.

[0109] The above-described coated sulfide-containing electrolyte material can be used as a solid electrolyte for an all-solid-state battery. The all-solid-state battery includes a positive electrode and a negative electrode, with a solid electrolyte interposed between them.

[0110] Meanwhile, the positive and negative electrodes of the all-solid-state battery according to aspects of the present disclosure are not particularly limited, and any suitable ones known in the art may be used.

[0111] The all-solid-state battery proposed according to aspects of the present disclosure defines the composition of the solid electrolyte as described above, and other elements constituting the battery, i.e., the positive electrode and the negative electrode, are not specifically limited in the present disclosure and follow the description below.

[0112] In one aspect, the negative electrode of the all-solid-state battery may be lithium metal alone, or the negative electrode active material may be laminated on the negative electrode current collector.

[0113] The negative electrode current collector is not particularly limited as long as it is conductive and does not cause any chemical change in the all-solid-state battery, and examples thereof include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel whose surface is treated with carbon, nickel, titanium, silver, etc., or an aluminum-cadmium alloy. In addition, the negative electrode current collector, like the positive electrode current collector, may include various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a non-woven fabric having fine irregularities formed on the surface.

[0114] The negative active material may be at least one of lithium metal, a lithium alloy, a lithium metal composite oxide, a lithium-containing titanium composite oxide (LTO), and a combination 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. In addition, the lithium metal composite oxide may be an oxide (MeO) of lithium and any one metal (Me) selected from the group consisting of Si, Sn, Zn, Mg, Cd, Ce, Ni, and Fe. x ) may be, for example, LixFe2O3(0≤x≤1) or LixWO2(0≤x≤1).

[0115] In addition, the negative 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　and oxides such as Bi2O5; and carbon-containing negative electrode active materials such as crystalline carbon, amorphous carbon or carbon composites, which may be used alone or in combination of two or more.

[0116] Additionally, the electrode may contain a conductive agent, a solid electrolyte, or a dispersant in addition to the active material. Examples of the conductive agent include nickel powder, cobalt oxide, titanium oxide, or carbon. The carbon may include at least one selected from the group consisting of Ketjen black, acetylene black, furnace black, graphite, carbon fiber, and fullerene.

[0117] Example

[0118] The following examples are not intended to be limiting. The disclosure provides numerous different aspects for implementing the features of the present disclosure, and the following examples illustrate specific aspects. It will be appreciated that other variations and methods known to those skilled in the art may be applied to the experimental procedures described below without departing from the scope of the present disclosure.

[0119] Synthesis Example 1 - Composite Anode

[0120] Milled sulfur was prepared by milling sulfur (1 g batch, Sigma Aldrich) with 5 mm balls at 400 rpm for 10 h using an Emax high-power mill.

[0121] 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.

[0122] 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 1 g batch was milled with a 5 mm ball at 500 rpm for 1 hour.

[0123] The cathode material was chemically stable and no new bulk phases were present. In the PXRD diffractograms and Raman spectra of Figures 1a and 1b, it can be seen that the peaks present individually in LPSCl and sulfur (lower curves) coexist in the mixture of LPSCl and sulfur. The upper curves of Figures 1a and 1b represent LPSCl and a mixture of 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 cathode mixture of LPSCl, sulfur, and acetylene black (AB).

[0124] The milled anode material was pressed at 375 MPa for 5 minutes to form a composite anode.

[0125] Experimental Example 1

[0126] The milled cathode material from Synthesis Example 1 was charged at 5 mAh cm using a fixed gap holder, as shown in Fig. 4a. -2 , Li1In1 available capacity 110mAh g -1 And the areal capacity performance was tested at NP ratio 2.

[0127] Figure 3a shows the design area capacity of 1.6 mAh cm -2 Voltage vs. Li in case of + Capacity (mAh g) as a function of / Li(V) -1 ) shows the test results for the first cycle, where the first cycle is 0.07 mA cm -2 The second cycle was tested at a higher current density of 0.8 mA cm -2 It was tested at 0.8 mA cm. Figure 3b shows -2 Specific capacity (mAh g) as a function of cycle number when operating at -1) are shown. Figures 3a and 3b demonstrate the high-rate cycling performance obtained using the milled cathode material. Excellent retention and stable cycling were observed at high rates, and a capacity retention of 95.5% was achieved after 485 cycles.

[0128] Figure 4a shows the device used for testing, 5 mAh cm -2 , Li1In1 available capacity 110mAh g -1 and a device with a fixed gap holder of NP ratio 2. Figure 4b shows voltage vs. Li + S capacity (mAh g) as a function of / Li(V) -1 ) is shown. Figure 4c shows the S capacity (mAh g) as a function of the number of cycles. -1 ) are shown. As can be seen, the C / 2 performance is 2.8 mA cm, which exceeds Li1In1CCD. -2 was unstable, and the C / 5 performance was 1.12 mA cm -2 was stable. In case of high area load, the limiting factor appears to be the anode.

[0129] Experimental Example 2

[0130] The setup was performed as shown in Fig. 5a at a constant pressure of 10 MPa (according to literature [S.-Y. Ham et al., Energy Storage Materials 55:455-462 (2023)]), and the anode area capacity was 1.6-5 mAh cm -2 The performance was evaluated when LPSCl was used as an 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 an anode material, and Li metal was used as an anode. Each had a capacity of 1.6 mAh cm -2 and 5mAh cm -2 Voltage vs. Li when tested in + S capacity (mAh g) as a function of / Li(V) -1) are shown in Figures 5b and 5c.

[0131] Using the same setup as shown in Fig. 5a, S capacity (mAh g) as a function of cycle number -1 ) are shown in Fig. 6a and Fig. 6b, respectively. Fig. 6a shows 1.6 mAh cm -2 S capacity (mAh g) as a function of cycle number when evaluated at -1 ) is shown. Figure 6b shows the results for 5 mAh cm -2 S capacity (mAh g) as a function of cycle number when evaluated at -1 ) shows the results.

[0132] Experimental Example 3

[0133] The procedure described in Experimental Example 1 was followed, 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 performances of LZC (see Figures 7a and 7b), LYC (see Figures 7c and 7d), and LPSCl (see Figures 7e and 7f) as ionic conductors within the cathode composite are shown. The LPSCl solid electrolyte remains an ideal choice because of its reversibility within the operating voltage range of 1 V-3 V for sulfur redox for Li / Li+. The chloride electrolyte achieves sufficient capacity utilization, but suffers from lower stability due to its higher reduction potential, which reduces the ionic conductivity within the cathode composite.

[0134] Comparative Example 1

[0135] The setup was carried out at a constant pressure of 10 MPa and 1.6 mAh cm -2As shown in Fig. 5a, the anode area capacity was as follows. 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, but the mixture was not ball milled as shown in Fig. 7g, and the results were compared with those of the milled anode as shown in Fig. 7e. In both cases, Li1In1 was used as the anode.

[0136] Those skilled in the art will appreciate that aspects of the present disclosure can be practiced within a wide range of equivalent parameters without affecting the scope of the disclosure set forth herein. All publications, patent applications, and patents disclosed herein are incorporated by reference in their entirety.

Claims

1. As a composite cathode, The above composite anode is, A plurality of sulfur particles having an average 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 Including, The above 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 m 2 g -1 150m inland 2 g -1 , and has 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; A composite anode formed by pressing the above-mentioned milled mixture.

2. In paragraph 1, A composite anode having a weight ratio of the plurality of sulfur particles, the plurality of sulfur-containing solid electrolyte particles, and the conductive material of 20-50:40-60:10-30.

3. In paragraph 1, The above plurality of acetylene black carbon particles are non-porous composite anodes.

4. In paragraph 1, The above plurality of acetylene black carbon particles have a BET specific surface area of 75 m 2 g -1 125 m inland 2 g -1 A composite anode.

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); 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 m 2 g -1 150m inland 2 g -1 A step of providing a conductive material having a quasi-crystalline structure; A step of forming a milled mixture by milling the plurality of sulfur particles, the plurality of sulfur-containing solid electrolyte particles, and the conductive material; and Comprising a step of pressing the above milled mixture to form a composite anode, Method for manufacturing a composite anode.

6. In paragraph 5, The above milling is performed at 200-500 rpm.

7. In paragraph 5, The above milling is performed at 400-500 rpm.

8. In paragraph 5, The above milling is performed for 1 hour.

9. In paragraph 5, A method in which the above pressurization is performed at a pressure of 100 MPa to 500 MPa.

10. In paragraph 5, A method in which the above pressurization is performed for 1 to 60 minutes.

11. In paragraph 5, A method 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.

12. In paragraph 5, A method wherein the above plurality of acetylene black carbon particles have an average particle size of 40 nm.

13. In paragraph 5, The above plurality of acetylene black carbon particles have a BET specific surface area of 90 m 2 g -1 How to be.

14. In paragraph 5, A method wherein the plurality of acetylene black carbon particles are nonporous.

15. In paragraph 5, A method wherein the above plurality of acetylene black carbons have a quasi-crystalline structure.

16. A composite anode manufactured according to the method of Article 5.

17. Cathode; Composite anode according to paragraph 1; and solid electrolyte An all-solid-state battery comprising:

18. In paragraph 17, An all-solid-state battery wherein the composite anode comprises a sulfur channel in contact with the solid electrolyte.

19. In paragraph 18, The above-mentioned sulfur channel is an all-solid-state battery having a channel diameter in the range of 10 microns to 40 microns.

20. In paragraph 1, Composite anode containing amorphous sulfur.

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