Lithium secondary battery and its manufacturing method

Abstract

The present application provides a lithium secondary battery and a manufacturing method thereof. The lithium secondary battery includes a separator, a cathode, and an anode. The cathode is disposed on one side of the separator and includes a cathode active material, the cathode active material including a first composite material based on a high-nickel material. The anode is disposed on the opposite side of the separator and includes an anode active material, the anode active material including a second composite material composed of silicon particles and a high-entropy material. The high-entropy material is composed of at least five elements, each of which accounts for 50% or less of the five elements.

Description

[Technical Field]

[0001] The present application relates to an electrode material and a method for preparing the same, in particular to a lithium secondary battery and a method for producing the same, as well as a lattice stabilizing material, a cathode active material doped with the lattice stabilizing material, a method for preparing the same, and a lithium secondary battery produced with the cathode active material. [Background technology]

[0002] Artificial and natural graphite are currently the most commonly used anode (also called negative electrode) materials for lithium batteries. However, the electrical capacity of currently commercially available graphite anodes is close to their theoretical capacity (372 mAh / g). Therefore, in order to increase the energy density of batteries, the next focus is to find materials with higher electrical capacity.

[0003] Silicon-based anodes are a key trend in the next stage. Silicon has a high theoretical capacity of 4200 mAh / g, more than 10 times that of current graphite anode materials. With abundant reserves and low cost, silicon is the most promising candidate for the next generation of anode materials for lithium-ion batteries. However, as silicon absorbs and releases lithium during charging and discharging, it forms several crystalline phases with different proportions, resulting in a severe volumetric effect. During charging, silicon expands by 300% (compared to only 16% for conventional graphite anodes), resulting in volumetric shrinkage during discharging. Repeated volumetric changes can easily lead to problems such as silicon particle rupture, material powdering, and electrode sheet shedding, resulting in poor cycle performance. Furthermore, the expansion process can easily destroy the solid electrolyte interphase film (SEI) on the anode surface, which then reforms during discharging. Therefore, the SEI film on the silicon surface is constantly undergoing a dynamic process of destruction and reconstruction, resulting in a continuous increase in the thickness of the SEI film, an increase in the interfacial impedance, consumption of the active material, a decrease in the electrical capacity, and poor coulombic efficiency, all of which adversely affect the application of silicon anodes to lithium secondary batteries.

[0004] In other words, the characteristics of silicon materials result in poor cycle characteristics and initial coulombic efficiency of the battery, making it difficult to commercialize silicon materials in practical applications.

[0005] On the other hand, the cathode material of a lithium battery is generally made of metal oxides, such as a combination of one or more oxides of manganese, nickel, cobalt, aluminum, chromium, etc. Common cathode materials are ternary materials, such as lithium aluminum cobalt oxide (LiCoO), lithium nickel oxide (LiNiO), or lithium iron phosphate (LiFePO). However, the development of these cathode materials is limited, and it is difficult to simultaneously satisfy several requirements, such as high cycle efficiency, low cost, and high safety.

[0006] Furthermore, in nickel-manganese-cobalt ternary / quaternary cathode materials, increasing the nickel content provides the advantage of high capacity. Nickel has advantages over cobalt, such as low cost and abundant raw material sources. However, as the cobalt content decreases, the degree of cation order in the lattice decreases, gradually destabilizing the material structure. Meanwhile, increasing the nickel content makes the material more susceptible to moisture absorption, promoting reactions between lithium ions and water and carbon dioxide, leading to the deposition of impurities and increasing the interfacial internal resistance on the positive electrode surface. Furthermore, because nickel ions in the delithiated state are highly reactive and unstable, high nickel content makes them more susceptible to reactions with the solution and electrolyte, resulting in accelerated capacity loss during cycle charging and discharging and capacity fade at high temperatures. As the nickel content in the material increases, the safety of the material decreases, and lithium batteries may experience safety risks such as thermal runaway, short circuiting, and explosion under conditions such as high temperature, overcharge, and overdischarge.

[0007] Lithium iron manganese phosphate is a relatively safe cathode material compared to high-nickel ternary materials, and has a relatively high operating voltage, but a lower volumetric energy density than high-nickel ternary materials. In some applications, the electrode packing density of cathodes made with lithium iron manganese phosphate is only about 2.2 g / cm. 3 whereas the electrode pressed density made from ternary materials is 3.4 g / cm 3 can be achieved, and there is a significant difference between the two.

[0008] To improve the safety of lithium-ion batteries, some studies have proposed adding lithium iron manganese phosphate (LiFeMn) to high-nickel ternary materials to prepare cathode materials. However, existing powder-based LiFeMn phosphate additives are difficult to mix uniformly with ternary materials. To effectively improve safety, the blend ratio of LiFeMn phosphate typically needs to be at least 25%. However, due to the low volumetric energy density of LiFeMn phosphate itself, blending a high proportion of LiFeMn phosphate into a ternary material inevitably significantly reduces the volumetric energy density of the ternary material. Furthermore, a high proportion of LiFeMn phosphate significantly changes the electrode density. Therefore, blending LiFeMn phosphate requires adjusting the battery composition accordingly, making it unsuitable for mass production and cross-product applications. Summary of the Invention [Problem to be solved by the invention]

[0009] In order to solve the problems described in the prior art, the present application proposes a novel lithium secondary battery and a method for manufacturing the same. [Means for solving the problem]

[0010] The present application provides a lithium secondary battery comprising: a separator; a cathode disposed on one side of the separator and including a cathode active material, the cathode active material comprising a first composite material based on a high-nickel material; and an anode disposed on the opposite side of the separator and including an anode active material, the anode active material comprising a second composite material consisting of silicon particles and a high-entropy material, wherein the high-entropy material is composed of at least five elements, and the proportion of each of the elements in the high-entropy material is 50% or less.

[0011] The present application provides a method for manufacturing a lithium secondary battery, the method comprising the steps of: manufacturing a positive electrode using a cathode active material; manufacturing a negative electrode using an anode active material; stacking the positive electrode, a separator, and the negative electrode alternately and placing the stacked electrodes in an electrolyte solution; and encapsulating the positive electrode, the separator, and the negative electrode placed in the electrolyte solution in a plastic film, wherein the cathode active material is prepared from a first composite material based on a high-nickel material, and the anode active material is prepared from a second composite material consisting of silicon particles and a high-entropy material, the high-entropy material being composed of at least five elements, and the proportion of each of the elements in the high-entropy material being 50% or less. [Brief explanation of the drawings]

[0012] In order to more clearly describe the embodiments of the present application or the technical solutions in the prior art, the drawings necessary for describing the embodiments or the prior art will be briefly described below. However, the drawings in the following description are only some embodiments of the present application, and it is obvious to those skilled in the art that other drawings can be obtained based on these drawings without any creative efforts. [Figure 1] 1 is a schematic diagram illustrating the configuration of a lithium secondary battery according to some embodiments of the present application. [Figure 2A] FIG. 2 is a schematic diagram of the composition of a cathode material layer in some embodiments of the present application. [Figure 2B]FIG. 2 is a schematic diagram of the composition of an anode material layer according to some embodiments of the present application. [Figure 3A] 1 is a schematic diagram of a cross-sectional structure of a cathode active material according to some embodiments of the present application; [Figure 3B] 1 is a schematic diagram of a cross-sectional structure of an anode active material according to some embodiments of the present application; [Figure 4] 1 is a flow diagram of steps for preparing cathode active materials according to some embodiments of the present application. [Figure 5] 1 is a flow diagram of steps for preparing an anode active material according to some embodiments of the present application. [Figure 6] 1 is a flow diagram of steps for preparing an anode active material according to some embodiments of the present application. [Figure 7] 1 is a flow diagram of steps for a method of preparing a lattice-stabilized material according to some embodiments of the present application. [Figure 8] 1 shows the results of analysis of the anode active material prepared in Experimental Example 1 using an X-ray diffractometer. [Figure 9] 1 is a scanning electron microscope image of the anode active material prepared in Experimental Example 4. [Figure 10] 1 is a transmission electron microscope image of the anode active material prepared in Experimental Example 2. [Figure 11] 10 shows test results after activation of the lithium secondary battery manufactured in Experimental Example 15. [Figure 12] 1 shows the test results of a needle puncture test performed on the lithium secondary batteries manufactured in Experimental Example 16 and Comparative Example 2. [Figure 13] 1 shows test conditions for needle puncture tests in Experimental Example 16 and Comparative Example 2. [Figure 14] FIG. 10 is a comparison of scanning electron microscope images of the positive electrodes produced in Experimental Example 19 and Comparative Example 6. [Figure 15] 10 is a photograph showing a needle puncture test using the lithium battery produced in Comparative Example 6. [Figure 16] 10 is a photograph showing a needle puncture test using the lithium battery produced in Comparative Example 5. [Figure 17]10 is a photograph showing a needle puncture test using the lithium battery manufactured in Experimental Example 18. DETAILED DESCRIPTION OF THE INVENTION

[0013] To make the features and advantages of the present application more clearly understandable, specific embodiments of the present application will be described in detail below with reference to the drawings. The following description includes specific information regarding the embodiments of the present application. The drawings of the present application and the accompanying detailed description are merely exemplary embodiments. However, the present application is not limited to these exemplary embodiments. Other variations and embodiments of the present application will be apparent to those skilled in the art. Unless otherwise specified, identical or corresponding elements in the drawings may be indicated by identical or corresponding reference numerals. Furthermore, the drawings and illustrations in the present application are generally not drawn to scale and are not intended to correspond to actual relative dimensions.

[0014] For purposes of consistency and ease of understanding, reference numerals are used in the exemplary drawings to denote like features (although in some instances not so shown), however, features in different embodiments may differ in other respects and should not be limited to those shown in the drawings.

[0015] Terms such as "first," "second," and "third" used in the present specification and the above drawings are intended to distinguish between different items, regions, layers, or steps, and not to describe a particular order (unless expressly required by the claims). Furthermore, the term "comprises" and variations thereof are intended to cover an inclusive inclusion. The term "consisting of" is interpreted as an exclusive inclusion, i.e., any additional structural arrangement and / or material addition is not included within the scope of this term. However, those skilled in the art should understand that in an actual detection process, any material may be unexpectedly contaminated or doped with trace impurities. However, these detected trace impurities do not substantially affect the material, properties, and / or structure defined by this term, and therefore do not fall under the addition of the aforementioned additional structure and / or material.

[0016] Terms such as "connected" or "coupled" as referred to herein do not require that there be any intervening items between the items, i.e., an interconnection or coupling between two items may mean that the two items are directly connected / coupled to each other, or that the two items are connected / coupled to each other through other items.

[0017] All descriptions of specific numerical values ​​in this application, although not directly stated, include the meaning of "about" or "substantially," that is, these specific numerical values ​​cover a possible numerical error range to reflect possible unexpected influences and deviations in the selection of processes or materials. The numerical error range may include numerical changes that do not significantly change the structure, properties, or effects of the material, for example, a range of variation of 0 to 10%, and this error range is obvious to those skilled in the art.

[0018] Spatial relationships referred to in this application, such as "above," "below," "upward," "downward," "left side," "right side," etc., are illustrative descriptions based on the relative positions shown in the drawings and are not intended to limit the actual arrangement of material structures.

[0019] In this application, the terms anode and negative electrode are interchangeable terms, and the terms cathode and positive electrode are interchangeable terms.

[0020] FIG. 1 is a schematic diagram of the configuration of a lithium secondary battery according to some embodiments of the present application. Referring to FIG. 1, a lithium secondary battery 10 according to this embodiment includes a cathode electrode 11, a separator 12, and an anode electrode 13. The cathode electrode 11 includes a cathode material layer 110 and a cathode current collector 111, and the anode electrode 13 includes an anode material layer 130 and an anode current collector 131. The cathode electrode 11 and the anode electrode 13 are disposed on either side of the separator 12. Specifically, the cathode material layer 110 is disposed between the cathode current collector 111 and the separator 12 (on the upper side of the separator 12 as viewed in the drawing), and the anode material layer 130 is disposed between the anode current collector 131 and the separator 12 (on the lower side of the separator 12 as viewed in the drawing).

[0021] When the lithium secondary battery 10 is charged, lithium ions are released from the cathode material layer 110, pass through the separator 12 via the electrolyte, and are absorbed in the anode material layer 130. Conversely, when the lithium secondary battery 10 is discharged, lithium ions are released from the anode material layer 130, pass through the separator 12 via the electrolyte, and are absorbed in the cathode material layer 110, and at this time, electrons are output from the cathode current collector 111 due to valence balance.

[0022] In this embodiment, the cathode material layer 110 may be formed of one or more types of cathode active materials, and at least one of the cathode active materials may be, for example, a composite material based on a high-nickel material (or cathode composite material / first composite material). In the cathode composite material, a high-nickel material refers to a material in which nickel is the central metal for electrochemical oxidation-reduction reactions and the mole ratio of nickel atoms in the material exceeds 50%. The high-nickel material may include, for example, a material based on a lithium nickel oxide structure. The anode material layer 130 may be formed of any available anode active material, and the present application is not limited thereto. One of the anode active materials may be, for example, a composite material based on silicon particles (or anode composite material / second composite material).

[0023] The use of a silicon particle-based anode composite as the anode active material of the lithium secondary battery 10 can eliminate the volume effect of silicon during charge and discharge, provide good charge and discharge efficiency and electrical capacity, and also provide good oxidation resistance. On the other hand, the use of a high-nickel-based cathode composite as the cathode active material of the lithium secondary battery 10 can reduce the risk of thermal runaway in the cathode material layer 110 and avoid battery short circuits or explosions due to excessive expansion of the material, thereby further improving the safety of the lithium secondary battery 10.

[0024] The composition of the cathode material layer 110 and the specific structure of the cathode composite material will be further described below with reference to Figures 2A and 3A, where Figure 2A is a schematic diagram of the composition of the cathode material layer in some examples of the present application, and Figure 3A is a schematic diagram of the cross-sectional structure of the cathode active material in some examples of the present application.

[0025] 2A and 3A simultaneously, the cathode material layer 110 of this example includes a cathode active material M1, which is realized as a composite material 200 as shown in FIG. 3A. Specifically, the composite material 200 includes a high-nickel material 210 and a lattice stabilizing material 220, and the lattice stabilizing material 220 is formed on at least a portion of the surface of the high-nickel material 210. In other words, in the composite material 200, the lattice stabilizing material 220 is coated on the high-nickel material 210, forming a two-layer structure.

[0026] In some embodiments, the cathode material layer 110 further includes a conductive material M2, which may be any material that is electrically conductive but does not cause chemical changes in the battery, such as graphite (including artificial graphite or natural graphite), conductive carbon black, conductive fibers, conductive metal oxides, or conductive materials such as polyphenyl derivatives.

[0027] In some embodiments, the cathode material layer 110 may further include a binder M3 to improve the bonding strength between the separator 12 and the cathode current collector 111. In some embodiments, the cathode material layer 110 may further include a filler.

[0028] Specifically, the cathode active material / cathode material disclosed in this embodiment includes a composite material (or cathode composite material or high-nickel cathode composite material) consisting of a high-nickel material and a lattice stabilizing material, the lattice stabilizing material being formed on at least a partial region of the surface of the high-nickel material, and the proportion of nickel element in the high-nickel material is 50% or more. The proportion may be in atomic % or weight %. The lattice stabilizing material is, for example, nano-sized lithium iron manganese phosphate (LiFe 1-x Mn x PO4, LFMP) or lithium iron phosphate (LiFePO4), which has an olivine structure and can effectively stabilize the surface stability of high-nickel materials, reduce the risk of thermal runaway in the positive electrode material, and avoid the possibility of battery short circuit or explosion due to excessive expansion of the material.

[0029] In addition, since the cathode composite materials of the present invention have higher stability than common high-nickel materials, water may be used as a solvent system in addition to organic solvents in the preparation process. Compared with using organic solvents as a solvent system, water is non-toxic, safe, inexpensive, easily available, and easily recovered, which can further optimize the cost and safety of the entire preparation process.

[0030] The composition of the anode material layer 130 and the specific structure of the composite material will be further described below with reference to Figures 2B and 3B, where Figure 2B is a schematic diagram of the composition of the anode material layer in some examples of the present application, and Figure 3B is a schematic diagram of the cross-sectional structure of the anode active material in some examples of the present application.

[0031] 2B and 3B simultaneously, the anode material layer 130 of this embodiment includes an anode active material M4, which is realized as a composite material 300 as shown in FIG. 3B. Specifically, the composite material 300 includes silicon particles 310 and a high-entropy material 320, and the high-entropy material 320 is formed on at least a portion of the surface of the silicon particles 310. In other words, in the composite material 300, the high-entropy material 320 is coated on the silicon particles 310, forming a two-layer high-entropy silicon composite material.

[0032] In some embodiments, the anode material layer 130 further includes a conductive material M5, which may be any material that is electrically conductive but does not cause chemical changes in the battery, such as graphite (including artificial graphite or natural graphite), conductive carbon black, conductive fibers, conductive metal oxides, or conductive materials such as polyphenyl derivatives.

[0033] In some embodiments, the anode material layer 130 may further include a binder M6 to improve the bonding strength between the separator 12 and the anode current collector 131. In some embodiments, the anode material layer 130 may further include a filler.

[0034] Specifically, the anode active material / anode material disclosed in this embodiment includes a composite material composed of silicon particles and a high-entropy material, the high-entropy material being formed on at least a portion of the surface of the silicon particles, the high-entropy material being composed of at least five elements, each of which accounts for 50% or less of the total content of the elements. The percentages may be expressed in atomic percent or weight percent. The high-entropy material may also be referred to as a multi-component material, and the composite material may also be referred to as a high-entropy silicon composite material.

[0035] Composite materials can enhance the electrical conductivity of silicon materials by coating them with a high-entropy material. High-entropy materials can be composed of five or more elements. This overturns the conventional concept that the more elements added to a material, the more brittle it becomes. Furthermore, high-entropy materials maximize the effects of the high disorder of multiple elements, suppressing the formation of brittle compounds through the random distribution of each element's atoms. This can increase the strength and toughness of the material, improve its oxidation resistance, suppress silicon expansion, and enhance corrosion resistance. Therefore, composite materials formed by coating the surface of silicon materials with this high-entropy material can effectively improve the cycling and expansion problems of lithium secondary batteries.

[0036] Alternatively, the high-entropy material may include at least one of a high-entropy alloy, a high-entropy oxide, a high-entropy polymer, and a high-entropy ceramic.

[0037] Specifically, in this embodiment, a composite material is disclosed in which a high-entropy material is bonded to at least one region of the surface of a silicon particle, and the composite material is, for example, a silicon particle having a chemical formula of Si 1-(x+y+m+n+z) (M x N y A m B n X z )O p (where p=0.1 to 2, M is, for example, a monovalent element, N is, for example, a divalent element, A is, for example, a trivalent element, B is, for example, a tetravalent element, and X is, for example, a bivalent element such as a transition metal element.) In some embodiments, x, y, m, n, and z may each be 0.2 or less.

[0038] In some embodiments, M may be lithium or sodium, N may be beryllium, magnesium, calcium, strontium, or barium, A may be boron, aluminum, gallium, or indium, B may be carbon, silicon, germanium, tin, or lead, and X may be any element. By mixing precursors of the above different elements, performing a synthesis reaction between silicon materials, and then performing appropriate heat treatment, the composite of the silicon material and the high-entropy material can be used as an anode material for lithium batteries.

[0039] The silicon particles coated with the high-entropy material can be prepared by doping pure silicon wafers or N-type or P-type silicon wafers commonly used in semiconductor processing with, for example, 0.001% to 2% by weight of a III-V group element. In the preparation process, the silicon material may be crushed into powder before the reaction. To facilitate subsequent high-entropy material synthesis, the particle size is controlled to 10 μm or less.

[0040] An embodiment of a method for preparing a cathode material according to the present invention will be described in detail below with reference to FIG. 4. FIG. 4 is a schematic diagram illustrating the steps of a method for preparing a cathode active material according to some embodiments of the present invention. Referring to FIG. 4, the method for preparing a cathode active material according to the present invention includes the steps of: adding water, an aqueous solution, or an organic solvent as a solvent system to a reaction vessel (step S110); adding a high-nickel material to the reaction vessel and mixing it with the solvent system (step S120); adding a lattice-stabilizing material to the solvent system (step S130); and thoroughly mixing the high-nickel material and the lattice-stabilizing material in the solvent system to produce a cathode composite material having a structure in which the lattice-stabilizing material is attached to at least a portion of the surface of the high-nickel material (step S140).

[0041] In step S110, when water is used as the solvent system, the water may be deionized water or any type of purified water. When an aqueous solution is used as the solvent system, in addition to the above-mentioned type of water, any substance that can be dissolved in water may be added to assist the subsequent reaction. When an organic solvent is used as the solvent system, the organic solvent may contain a pyrrolidine compound such as N-methyl-2-pyrrolidone (NMP).

[0042] In step S120, the high nickel material added can be any material with a nickel element percentage of more than 50%, such as lithium nickel cobalt aluminum oxide (LiNi 1-x-y Co x Al y O2, NCA), Lithium Nickel Manganese Cobalt Oxide (LiNi 1-x-y Mn x Co y O2, NMC), or LiNi 1-x-y Co x Mn yExamples of the additives include, but are not limited to, O2 (NCM). In this step, one or more of conductive carbon, dispersants, surfactants, carbon precursors, thickeners, and binders may be added to the solution. The conductive carbon may be a conductive carbon material such as carbon nanotubes, graphene, Super P, acetylene black, Ketjen black, nanohorns, or evaporated carbon. Examples of the binder may include, but are not limited to, polyvinylidene fluoride (PVDF) or styrene-butadiene rubber (SBR). Examples of the thickener may include, but are not limited to, carboxymethyl cellulose (CMC).

[0043] In step S130, the lattice stabilizer material may be, for example, LFMP. In some embodiments, lithium iron manganese phosphate may be dissolved in a solvent (e.g., deionized water or NMP) to form nano- or submicron particles dispersed in the solvent, and then added to the solution in step S120. Here, the solids content of the LFMP in the solvent may be, for example, 30-50%, preferably 40%, but this is not limited thereto. After addition, the LFMP accounts for 3-10%, preferably 5%, of the total cathode active material solution, but this is not limited thereto. The subsequent example in FIG. 7 further illustrates the flow of preparing the lattice stabilizer material.

[0044] In step S140, the high-nickel material and the lattice stabilizer material are thoroughly mixed to form the structure of the cathode composite material M1 as shown in FIG. 3A, which is the cathode active material of the lithium battery.

[0045] In some embodiments, the high-nickel composite / cathode composite described above can be applied to a cathode current collector (e.g., copper foil or aluminum foil) after the solution is stirred uniformly to produce a positive electrode / cathode electrode (e.g., 11).

[0046] An example of a method for preparing an anode material according to the present application will be described in detail below with reference to FIGS. 5 and 6. FIGS. 5 and 6 are schematic diagrams illustrating the steps of a method for preparing an anode active material according to some examples of the present application. Referring to FIG. 5, the method for preparing an anode active material according to this example includes the steps of: mixing water and an organic solvent in a reaction vessel (step S210); placing a silicon material in the reaction vessel and contacting it with the organic solvent (step S220); adding precursors of multiple elements constituting the high-entropy material to the organic solvent (step S230); and thoroughly mixing the precursors and the silicon material in the organic solvent to produce a composite material / high-entropy silicon composite material containing silicon particles and a high-entropy material composed of multiple elements (step S240).

[0047] The organic solvent may include, but is not limited to, one or more of alcohols (e.g., methanol, ethanol, isopropanol (IPA)) and mixed solvents (e.g., dispersants, surfactants, conductive carbon, and carbon precursors). The conductive carbon may be a conductive carbon material such as carbon nanotubes, graphene, Super P, acetylene black, Ketjen black, nanohorns, or evaporated carbon.

[0048] In step S210, the mixing ratio of water and organic solvent may be 50 / 50, but is not limited to this in the present application.

[0049] In step S220, the silicon material added may be N-type, P-type, or pure silicon without III-V doping. The inorganic material may include, but is not limited to, one or more of silicon, silicon powder, mixed powder of silicon and other metals, silicon-inorganic mixture, silicon alloy, silicon wafer, and silicon process waste slurry. The particle size of the silicon powder may be controlled to, for example, 1 μm to 10 μm.

[0050] In step S230, polyvinylpyrrolidone and silane may be added to the solution to prevent aggregation and precipitation during the formation of the composite material, and the concentration of the added polyvinylpyrrolidone may be 0.01% to 1% by weight. In some embodiments, a concentration of the added polyvinylpyrrolidone between 0.01% to 0.7% by weight is preferable. Furthermore, the concentration of the silane in the organic solvent may be 10% to 80% by weight. In some embodiments, a concentration of the added silane between 40% to 80% by weight is preferable.

[0051] In step S240, precursors of multiple elements may undergo hydrolysis and polymerization in a mixed solution of water and an organic solvent to generate a high-entropy material, which may then be mixed with a silicon material to form a colloidal suspension. In the colloidal suspension, the high-entropy material and the silicon material may coagulate, and the high-entropy material may be attached to at least a portion of the surface of the silicon particles to generate a composite material. In some embodiments, step S240 may be performed using a sol-gel method.

[0052] In other words, in the above steps S210 to S240, silicon powder is placed in a solvent made by mixing water and an organic solvent in an appropriate ratio, at least five different elements are dissolved and added to a reaction tank, and the resulting material is synthesized using an appropriate synthesis method (e.g., the sol-gel method), followed by drying, pulverization, and high-temperature sintering to complete a high-entropy silicon composite material.

[0053] An example of the detailed step flow of the above-mentioned method for preparing an anode active material will be further described below with reference to Fig. 6. Referring to Fig. 6, the method for preparing an anode active material in this example includes the steps of mixing water and an organic solvent in a reaction vessel (step S310), processing a silicon material into powdered silicon units (step S320), placing the silicon units in the reaction vessel and contacting them with an organic solvent (step S330), adding precursors of multiple elements that are constituent elements of a high-entropy material to the organic solvent (step S340), thoroughly mixing the precursors and the silicon units in the mixed solution of water and the organic solvent to cause hydrolysis and polymerization reactions to produce a composite material containing silicon particles and a high-entropy material (step S350), drying the composite material (step S360), and heat-treating the dried composite material to finally produce a powdered composite material (step S370).

[0054] Specifically, through steps S310 to S350, the composite material is essentially produced but mixed in the solution, and then through steps S360 and S370, the composite material can be further separated as an anode active material.

[0055] The drying step S360 can be performed by drying the gel composite material in an inert environment (e.g., a non-oxygen environment, a vacuum or non-vacuum environment) at a first temperature, which may be, for example, 50°C to 150°C, preferably 120°C.

[0056] Next, the heat treatment step S370 can be performed by heating the dried gel at a second temperature in an inert environment, which may be, for example, 900°C to 1500°C. In some embodiments, the heating time in step S270 can be 2 to 5 hours. After the heat treatment is complete, the powdered composite material is separated. The heat-treated composite material can be further decomposed, dispersed, and classified to obtain the finished anode active material. The overall processing steps are simple and the processing time is short, allowing for mass production at low cost.

[0057] Furthermore, in the high-entropy silicon composite materials of the examples of the present application, even if the silicon particles do not need to have nanometer particle sizes, the anode active material prepared from the high-entropy silicon composite and the lithium secondary battery thereof can exhibit good material properties such as high cycle characteristics and good Coulomb efficiency. This eliminates the need for plasma treatment to convert the silicon material into plasma during the preparation process, further reducing the cost of the preparation process and making it suitable for commercialization and mass production.

[0058] In some embodiments, the high-entropy silicon composite / anode composite is prepared by the steps of: mixing at least 5 wt. % of the high-entropy material and graphite to prepare an anode active material accounting for 95 wt. % of the total weight of the anode; adding 0.1 wt. % of single-walled carbon nanotubes; adding a binder (e.g., 4.9 wt. % of PVDF); dissolving the mixture in an organic solvent (e.g., NMP); stirring the solution uniformly; and then applying it to a current collector (e.g., copper foil or aluminum foil) to prepare a negative / anode electrode (e.g., 13).

[0059] In another embodiment, the binder may be SBR. In the embodiment using SBR as the binder, the amount of SBR added may be 2.5 wt %. Also, CMC may be added as a thickener, and the solid content of the added CMC may be, for example, 2.4 wt %.

[0060] In the actual preparation process, the cathode electrode is baked at 110°C, then cold-pressed, trimmed, cut, slit, and tab-welded to form a sheet cathode plate. The anode electrode is baked at 100°C, then cold-pressed, trimmed, cut, slit, and tab-welded to form a sheet anode plate. The cathode, separator, and anode plate sheets are alternately stacked, filled with electrolyte, and sealed in plastic film to produce a lithium secondary battery.

[0061] 7 is a schematic diagram of a process flow for preparing a lattice-stabilized material according to some embodiments of the present application. Referring to FIG. 7, in this embodiment, the process includes adding a dispersant to an organic solvent (step S410), adding powdered LFMP to the organic solvent containing the dispersant to form a mixed material (step S420), and grinding the mixed material to produce a slurry of lattice-stabilized material in which nano- or submicron-sized LFMP particles are dispersed (step S430).

[0062] The organic solvent may include, for example, a pyrrolidine compound (e.g., NMP), and the dispersant may include, for example, one or more of polyvinylpyrrolidone (PVP), pyrazine hexahydrate, ethylenepolyamine, N,N-dimethylaminopropylamine, diethylethanolamine, 9-octadecenamine, and a quaternary ammonium salt.

[0063] In some embodiments, the mixing ratio of the dispersant, the organic solvent, and the LFMP may be 1:15:6.5-25.

[0064] In some embodiments, in step S410, a suspending agent may be further added to stably suspend the LFMP particles dispersed in the slurry-like lattice-stabilized material in the slurry, and the suspending agent may include an olefin compound, such as one or more of polyvinylidene fluoride (PVDF), vinylidene fluoride-chlorotrifluoroethylene copolymer (VDF-CTFE), polyvinyl fluoride (PVF), ethylene-chlorotrifluoroethylene copolymer (ECTFE), perfluorosulfonic acid resin (XR resin), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether (EPE), polychlorotrifluoroethylene (PCTFE), and polytetrafluoroethylene (PTFE).

[0065] In some embodiments, the mixing ratio of the suspending agent, the dispersing agent, the organic solvent, and the LFMP may be 1:20:300:130-200.

[0066] In some embodiments, step S410 may further include adding a flame retardant, such as a phosphazene, to slow down the thermal runaway reaction by performing endothermic decomposition when thermal runaway occurs in the lithium ion battery.

[0067] In some embodiments, the mixing ratio of the phosphazene flame retardant, dispersant, organic solvent, and LFMP may be 1:2:30:13-20.

[0068] In some embodiments, in step S420, conductive carbon may be further added to improve the conductivity and reactivity of the lattice-stabilized material, and the conductive carbon may be a conductive carbon material such as carbon nanotubes (single-walled or multi-walled), graphene, Super P, acetylene black, Ketjen black, nanohorns, evaporated carbon, etc.

[0069] In some embodiments, the mixing ratio of the conductive carbon, the dispersant, the organic solvent, and the LFMP may be 1:2:30:13-20.

[0070] The disclosure of the specific numerical values ​​above is merely a preferred selection in the specific experimental conditions above, and what is substantially disclosed in this embodiment includes not only the specific numerical values ​​above, but also an effective offset range, such as ±15%, that can achieve approximate or the same preferred effect. In other words, when specific numerical values ​​are limited in the claims, the corresponding numerical values ​​can equally include a deviation range of ±15% (as long as efficiency can be realized).

[0071] The structures and preparation methods of the cathode active material and anode active material disclosed in the various examples above can be used alone or in combination. For example, the cathode active material using the high-nickel composite material described in the examples above can optimize the safety of a lithium secondary battery even when combined with a common anode structure / material. Furthermore, the anode active material using the high-entropy silicon composite material described in the examples above can improve cycle efficiency and capacity even when combined with a common cathode structure / material to produce a lithium secondary battery.

[0072] By combining the high nickel composite material and the high entropy silicon composite material of the above embodiment to manufacture the cathode and anode electrodes of lithium secondary batteries, the efficiency and safety of the lithium secondary batteries can be further improved, and the preparation process using pure water as the solvent system can meet environmental protection requirements, providing commercial batteries that combine safety and high capacity. Therefore, the technical effects achieved by the lithium secondary batteries prepared by combining the two composite materials are far superior to those achieved by either material alone, and can bring about unexpected advantages.

[0073] The structures and preparation processes of the anode composite material, lattice stabilizer material, and cathode composite material containing the lattice stabilizer are described below in several experimental examples. Among these, experimental examples 1 to 6 are experimental examples for preparing anode active materials, experimental examples 7 to 11 are experimental examples for preparing lattice stabilizer materials, and experimental examples 12 to 20 are experimental examples for manufacturing cathode active materials and lithium batteries using the same.

[0074] Step flow of Experimental Example 1: 500 g of water and 50% of an organic solvent were added to a reaction vessel. The organic solvent was ethanol, and the water contained 4% graphene and polyvinylpyrrolidone. The solvent in the reaction vessel contained 2% aluminum chloride, 0.6% magnesium nitrate, and 0.2% lithium carbonate, with a silane solid content of 80%. After uniform stirring for 2 hours, 50 g of silicon powder with a particle size controlled to 1-10 μm was added and mixed. After uniform stirring and dispersion, the mixture was dried at 120°C and subjected to high-temperature heat treatment at 1100°C for 2 hours in a nitrogen environment. After decomposition, dispersion, and classification, a particle powder of high-entropy silicon composite material was produced. Using the high-entropy silicon composite powder as the anode active material, a coin-shaped battery with a diameter of 20 mm and a height of 3.2 mm was fabricated, in which the high-entropy silicon composite contained at least 5 wt% silicon powder, the mixture of artificial graphite and the anode active material accounted for 80 wt% of the total anode weight, the superconducting carbon black (super P) conductive material accounted for 10 wt% of the total anode weight, and the polyvinylidene fluoride (PVDF) binder accounted for 10 wt% of the total anode weight. Figure 8 shows the results of X-ray diffractometry (XRD) analysis of the anode active material produced in Experimental Example 1. Comparing the analysis results of the powder in Experimental Example 1 with the analysis results of X-ray diffractometry using a silicon standard peak (ICSD-51688-Si), it was confirmed that an amorphous silicon compound was produced in the manufacturing process.

[0075] Step flow of Experimental Example 2: 500 g of water and 50% of an organic solvent were added to a reaction vessel. The organic solvent was isopropanol, and the water contained 4% carbon nanotubes and polyvinylpyrrolidone. The solvent in the reaction vessel contained 2% aluminum nitrate, 0.6% barium nitrate, and 0.2% lithium carbonate. The solid content of the silane in the solvent (dissolved only in the organic solvent) was 80%. After uniform stirring for 2 hours, 50 g of silicon powder with a particle size of 1-10 μm was added and mixed. After uniform stirring and dispersion, the mixture was dried at 120°C and heat-treated at 1100°C for 3 hours in a nitrogen environment. After decomposition, dispersion, and classification, a high-entropy silicon composite particle powder was produced. A coin-shaped battery with a diameter of 20 mm and a height of 3.2 mm was fabricated using a high-entropy silicon composite powder as the anode active material, where the high-entropy silicon composite contained at least 5 wt% silicon powder, the mixture of artificial graphite and the anode active material accounted for 80 wt% of the total anode weight, the superconducting carbon black (super P) conductive material accounted for 10 wt% of the total anode weight, and the polyvinylidene fluoride (PVDF) binder accounted for 10 wt% of the total anode weight. Figure 10 is a transmission electron microscope (TEM) image of the anode active material produced in Experimental Example 2. Referring to Figure 10, when the powder sample obtained in Experimental Example 2 was observed with a transmission electron microscope, it was found that amorphous silicon compounds of about 20 nm in size were formed on the surfaces of the original silicon particles and coated the surface of the silicon anode.

[0076] Step flow of Experimental Example 3: 500 g of aqueous solution and 50% of organic solvent were added to a reaction vessel. The organic solvent was ethanol, and the water contained 6% fructose and 6% aqueous ammonia. The solvent in the reaction vessel contained 2% aluminum hydroxide, 0.6% magnesium hydroxide, and 0.25% lithium hydroxide. The solid content of silane in the solvent was 80%. After uniform stirring for 2 hours, 50 g of silicon powder with a particle size of 0.5-1 μm was added and mixed. After uniform stirring and dispersion, the mixture was dried at 120°C and subjected to high-temperature heat treatment at 1100°C for 3 hours in a nitrogen environment. After decomposition, dispersion, and classification, a particle powder of high-entropy silicon composite material was produced. A coin-shaped battery with a diameter of 20 mm and a height of 3.2 mm was fabricated using a high-entropy silicon composite powder as the anode active material, where the high-entropy silicon composite contained at least 5 wt% silicon powder, the mixture of artificial graphite and the anode active material accounted for 80 wt% of the total anode weight, the superconducting carbon black (super P) conductive material accounted for 10 wt% of the total anode weight, and the polyvinylidene fluoride (PVDF) binder accounted for 10 wt% of the total anode weight.

[0077] Step flow of Experimental Example 4: 500 g of water and 50% of an organic solvent were added to a reaction vessel. The organic solvent was ethanol, and the water contained 4% carbon nanotubes and polyvinylpyrrolidone. The solvent in the reaction vessel contained 2% aluminum chloride, 0.6% calcium carbonate, and 0.2% lithium carbonate. The solid content of the silane in the solvent was 80%. After uniform stirring for 2 hours, 50 g of silicon powder with a particle size controlled to 1-10 μm was added and mixed. After uniform stirring and dispersion, the mixture was dried at 120°C and subjected to high-temperature heat treatment at 1100°C for 3 hours in a nitrogen environment. After decomposition, dispersion, and classification, a particle powder of high-entropy silicon composite material was produced. A coin-shaped battery with a diameter of 20 mm and a height of 3.2 mm was fabricated using a high-entropy silicon composite powder as the anode active material, where the high-entropy silicon composite contained at least 5 wt% silicon powder, the mixture of artificial graphite and the anode active material accounted for 80 wt% of the total anode weight, the superconducting carbon black (super P) conductive material accounted for 10 wt% of the total anode weight, and the polyvinylidene fluoride (PVDF) binder accounted for 10 wt% of the total anode weight. 9 is a scanning electron microscope (SEM) image of the anode active material prepared in Experimental Example 4. Referring to FIG. 9, when the powder sample obtained in Experimental Example 4 was observed with a scanning electron microscope, it was found that uniform carbon nanotubes (NCTs) formed by this manufacturing process were coated on the silicon material, forming a good conductive network.

[0078] Step flow for Experimental Example 5: 500 g of water and 50% of an organic solvent were added to a reaction vessel. The organic solvent was ethanol, and the water contained 4% graphene and polyvinylpyrrolidone. The solvent in the reaction vessel contained 2% aluminum nitrate, 0.6% barium nitrate, and 0.2% lithium carbonate. The solid content of the silane in the solvent was 80%. After uniform stirring for 2 hours, 50 g of silicon powder with a particle size of 1-10 μm was added and mixed. After uniform stirring and dispersion, the mixture was dried at 120°C and heat-treated at 1100°C for 3 hours in a nitrogen environment. After decomposition, dispersion, and classification, a high-entropy silicon composite particle powder was produced. A coin-shaped battery with a diameter of 20 mm and a height of 3.2 mm was fabricated using a high-entropy silicon composite powder as the anode active material, where the high-entropy silicon composite contained at least 5 wt% silicon powder, the mixture of artificial graphite and the anode active material accounted for 80 wt% of the total anode weight, the superconducting carbon black (super P) conductive material accounted for 10 wt% of the total anode weight, and the polyvinylidene fluoride (PVDF) binder accounted for 10 wt% of the total anode weight.

[0079] Step flow for Experimental Example 6: 500 g of water and 50% each of an organic solvent were added to a reaction vessel. The organic solvent was ethanol, and the water contained 4% graphene and polyvinylpyrrolidone. The solvent in the reaction vessel contained 2% aluminum nitrate, 0.6% barium nitrate, 0.2% lithium carbonate, and 0.005% yttrium nitrate. The solid content of the silane in the solvent was 80%. After uniform stirring for 2 hours, 50 g of silicon powder with a particle size of 1-10 μm was added and mixed. After uniform stirring and dispersion, the mixture was dried at 120°C and heat-treated at 1100°C for 3 hours in a nitrogen environment. After decomposition, dispersion, and classification, a particle powder of high-entropy silicon composite material was produced. A coin-shaped battery with a diameter of 20 mm and a height of 3.2 mm was fabricated using a high-entropy silicon composite powder as the anode active material, where the high-entropy silicon composite contained at least 5 wt% silicon powder, the mixture of artificial graphite and the anode active material accounted for 80 wt% of the total anode weight, the superconducting carbon black (super P) conductive material accounted for 10 wt% of the total anode weight, and the polyvinylidene fluoride (PVDF) binder accounted for 10 wt% of the total anode weight.

[0080] [Table 1]

[0081] Table 1 above summarizes the characteristic data regarding the charge-discharge efficiency of Experimental Examples 1 to 6 and Comparative Example 1. Comparative Example 1 is a coin-type battery that uses a silicon carbon anode active material (model: KSC-1265) manufactured by Shin-Etsu Corporation, and the anode active material / anode active material is not the composite material proposed in the present application.

[0082] According to the data of each experimental example disclosed in Table 1, it was found that the high-entropy silicon composite material produced by modifying the silicon powder was superior to currently commercially available silicon powder in terms of conductivity, capacity, first cycle efficiency, and efficiency after multiple cycles.

[0083] [Table 2]

[0084] Table 2 above summarizes the expansion characteristic data for Experimental Examples 1 to 6 and Comparative Example 1. According to the data for each experimental example disclosed in Table 2, it was found that the high-entropy silicon composite material produced by modifying silicon powder further reduced the expansion in the silicon negative electrode.

[0085] The preparation of lattice stabilized materials is further described below in Examples 7-11.

[0086] Step flow of Experimental Example 7: 300 g of organic solvent NMP and 200 g of LFMP powder were placed in a vertical mill pot and pulverized in a vertical sand mill to obtain submicron-scale LFMP powder of Experimental Example 7.

[0087] Step flow of Experimental Example 8: 20 g of PVP as a dispersant and 300 g of NMP, an organic solvent, were placed in a vertical mill pot and stirred to dissolve. After the PVP was completely dissolved, 180 g of LFMP powder was added and pulverized in a vertical sand mill to obtain the LFMP slurry of Experimental Example 8.

[0088] Step flow of Experimental Example 9: 20 g of PVP as a dispersant, 1.3 g of PVDF as a suspending agent, and 300 g of NMP, an organic solvent, were placed in a vertical mill pot and stirred to dissolve. After the PVP and PVDF were completely dissolved, 178.7 g of lithium iron manganese phosphate powder was added and pulverized in a vertical sand mill to obtain the LFMP slurry of Experimental Example 9.

[0089] Step flow of Experimental Example 10: 20 g of PVP as a dispersant, 1.3 g of PVDF as a suspending agent, and 300 g of NMP, an organic solvent, were placed in a vertical mill pot and stirred to dissolve. After the PVP and PVDF were completely dissolved, 168.7 g of LFMP powder and 10 g of multi-walled carbon nanotubes as conductive carbon were added and pulverized in a vertical sand mill to obtain the LFMP slurry of Experimental Example 10.

[0090] Step flow of Experimental Example 11: 20 g of PVP as a dispersant, 1.3 g of PVDF as a suspending agent, 10 g of a phosphazene flame retardant, and 300 g of the organic solvent NMP were placed in a vertical mill pot and stirred to dissolve. After the PVP and PVDF were completely dissolved, 158.7 g of LFMP powder and 10 g of multi-walled carbon nanotubes as conductive carbon were added and pulverized in a vertical sand mill to obtain the LFMP slurry of Experimental Example 10.

[0091] The amounts of PVP, PVDF, NMP, and LFMP used in the above examples are merely illustrative of some of the possible experimental examples of the present application, and the examples of the present application are not limited to the above numerical ranges. More specifically, in other experimental examples, the LFMP slurry can be produced at ratios of the amounts used that fit the following ranges:

number

[0092] [Table 3]

[0093] Table 3 above shows the results of stability tests (test temperature 55°C) using the lattice stabilized materials produced in Experimental Examples 7 to 11. According to the data of each Experimental Example disclosed in Table 3 above, it was found that the LFMP slurry produced by mixing and grinding the dispersant, organic solvent, and LFMP had better stability. The cathode active material and the production of a lithium battery using the same will be further described below with reference to Experimental Examples 12 to 20.

[0094] Step flow of Experimental Example 12: A high-nickel material, superconducting carbon (Super-P) as a conductive agent, and PVDF as a binder were uniformly mixed in a mass ratio of 97:1.5:1.5 and dissolved in NMP to prepare a cathode slurry with a predetermined viscosity. This was then added to a nano-LFMP slurry with a solid content of 40% in a total amount of 5% of the solid content of the original cathode slurry and mixed, preparing a cathode composite material in which LFMP was coated on a high-nickel material as the cathode active material. The cathode active material was then applied to an aluminum foil current collector, baked at 110°C, and cold pressed, trimmed, cut, slit, and tab welded to produce a positive electrode / positive electrode sheet for a lithium battery. In Experimental Example 12, the positive electrode was further combined with a negative electrode manufactured according to the following procedure (however, the present application is not limited to this procedure), to manufacture and test a lithium battery. The manufacturing procedure for the negative electrode includes the following steps: At least 5 wt% of the composite silicon high-entropy material and graphite were mixed to prepare the anode active material, which accounted for 95 wt% of the total anode weight. Single-walled carbon nanotubes were added to the anode slurry to achieve a single-walled carbon nanotube solids content of 0.1 wt%. PVDF was added to the anode slurry to achieve a PVDF solids content of 4.9 wt%. The anode slurry was dissolved in NMP as the solvent system, stirred uniformly, and then coated onto copper foil to produce the anode electrode. After baking at 110°C, the anode electrode / anode sheet for lithium batteries was fabricated by cold pressing, trimming, cutting, slitting, and tab welding. The above positive electrode sheet and negative electrode sheet were used as a positive electrode plate and a negative electrode plate, respectively, and a test lithium secondary battery was assembled in the following manner. The positive and negative electrodes were stacked alternately, and a separator was placed between them to define a storage area. After adding an electrolyte solution, the electrodes were placed in an aluminum plastic film, packaged, activated, and tested.

[0095] Step flow of Experimental Example 13: High-nickel positive electrode material, carbon nanotubes, and binder PVDF were uniformly mixed in a mass ratio of 98.5:0.5:1 and dissolved in NMP to prepare a positive electrode slurry with a predetermined viscosity. After that, the slurry was added to a nano-LFMP slurry with a solid content of 40% in a total amount of 5% of the solid content of the original positive electrode slurry and mixed, to prepare a cathode composite material in which LFMP was coated on a high-nickel material as the cathode active material. Then, a cathode active material was applied to an aluminum foil current collector, baked at 110°C, and then cold pressed, trimmed, cut, slit, and tab welded to produce a positive electrode / positive electrode sheet for a lithium battery. In Experimental Example 13, the above positive electrode was further combined with a negative electrode manufactured in the following manner (however, the present application is not limited to this procedure) to manufacture and test a lithium battery. The manufacturing procedure for the negative electrode includes the following: At least 5 wt% of the composite silicon high-entropy material and graphite were mixed to prepare the anode active material, which accounted for 95 wt% of the total anode weight. Single-walled carbon nanotubes were added to the anode slurry to achieve a single-walled carbon nanotube solids content of 0.1 wt%. PVDF was added to the anode slurry to achieve a PVDF solids content of 4.9 wt%. The anode slurry was dissolved in NMP as the solvent system, stirred uniformly, and then coated onto copper foil to produce the anode electrode. After baking at 110°C, the anode electrode / anode sheet for lithium batteries was fabricated by cold pressing, trimming, cutting, slitting, and tab welding. The above positive electrode sheet and negative electrode sheet were used as a positive electrode plate and a negative electrode plate, respectively, and a test lithium secondary battery was assembled in the following manner. The positive and negative electrodes were stacked alternately, and a separator was placed between them to define a storage area. After adding an electrolyte solution, the electrodes were placed in an aluminum plastic film, packaged, activated, and tested.

[0096] Step flow of Experimental Example 14: High-nickel positive electrode material, carbon nanotubes, and binder PVDF were uniformly mixed in a mass ratio of 98.5:0.5:1 and dissolved in NMP to prepare a positive electrode slurry with a predetermined viscosity. After that, the slurry was added to a nano-LFMP slurry with a solid content of 40% in a total amount of 5% of the solid content of the original positive electrode slurry and mixed, to prepare a cathode composite material in which LFMP was coated on a high-nickel material as the cathode active material. Then, a cathode active material was applied to an aluminum foil current collector, baked at 110°C, and then cold pressed, trimmed, cut, slit, and tab welded to produce a positive electrode / positive electrode sheet for a lithium battery. In Experimental Example 14, the positive electrode was further combined with a negative electrode manufactured in the following manner (however, the present application is not limited to this procedure) to manufacture and test a lithium battery. The manufacturing procedure for the negative electrode includes the following: The anode active material was prepared by mixing at least 5 wt% of a composite silicon high-entropy material and graphite. The anode active material accounted for 95 wt% of the total anode weight. Single-walled carbon nanotubes were added to the anode slurry to achieve a single-walled carbon nanotube solids content of 0.1 wt%. SBR was added to the anode slurry to achieve a SBR solids content of 2.5 wt%. CMC was added as a thickener at 2.4 wt%. The anode slurry was dissolved in deionized water as the solvent system, stirred uniformly, and then coated onto copper foil to produce the anode electrode. After baking at 100°C, the anode electrode / anode sheet for lithium batteries was produced by cold pressing, trimming, cutting, slitting, and tab welding. The above positive electrode sheet and negative electrode sheet were used as a positive electrode plate and a negative electrode plate, respectively, and a test lithium secondary battery was assembled in the following manner. A positive electrode plate and a negative electrode plate were prepared, and a separator was placed between them to define a storage area. The positive and negative electrodes were alternately stacked, and after adding an electrolyte solution, the battery was placed in an aluminum plastic film, packaged, activated, and tested.

[0097] Step flow of Experimental Example 15: High-nickel positive electrode material, carbon nanotubes, SBR binder, and CMC thickener were uniformly mixed in a mass ratio of 95.5:0.5:2:2 and dissolved in deionized water to prepare a positive electrode slurry with a predetermined viscosity. This was then added to a 40% solids aqueous slurry of dispersed nano-LFMP in an amount of 5% of the solids of the original positive electrode slurry and mixed to prepare a cathode active material in which high-nickel material was coated with LFMP. The cathode active material was then applied to an aluminum foil current collector, baked at 100°C, and cold pressed, trimmed, cut, slit, and tab welded to produce a positive electrode / positive electrode sheet for a lithium battery. In Experimental Example 15, the positive electrode was further combined with a negative electrode manufactured in the following manner (however, the present application is not limited to this procedure) to manufacture and test a lithium battery. The manufacturing procedure for the negative electrode includes the following: The anode active material was prepared by mixing at least 5 wt% of a composite silicon high-entropy material and graphite. The anode active material accounted for 95 wt% of the total anode weight. Single-walled carbon nanotubes were added to the anode slurry to achieve a single-walled carbon nanotube solids content of 0.1 wt%. SBR was added to the anode slurry to achieve a SBR solids content of 2.5 wt%. CMC was added as a thickener at 2.4 wt%. The anode slurry was dissolved in deionized water as the solvent system, stirred uniformly, and then coated onto copper foil to produce the anode electrode. After baking at 100°C, the anode electrode / anode sheet for lithium batteries was produced by cold pressing, trimming, cutting, slitting, and tab welding. The above positive electrode sheet and negative electrode sheet were used as a positive electrode plate and a negative electrode plate, respectively, and a test lithium secondary battery was assembled in the following manner. The positive and negative electrodes were stacked alternately, and a separator was placed between them to define a storage area. After adding an electrolyte solution, the electrodes were placed in an aluminum plastic film, packaged, activated, and tested. 11 shows the test results after activation of the lithium secondary battery manufactured in Experimental Example 15. Referring to FIG. 11, it can be seen that the high-nickel positive electrode using the aqueous solvent system prepared with the blending ratio of Experimental Example 15 did not experience the problem of swelling after activation.

[0098] Step flow of Experimental Example 16: High-nickel positive electrode material, carbon nanotubes, SBR binder, and CMC thickener were uniformly mixed in a mass ratio of 95.5:0.5:2:2 and dissolved in deionized water to prepare a positive electrode slurry with a predetermined viscosity. This was then added to a 40% solids aqueous slurry of dispersed nano-LFMP in an amount of 5% of the solids of the original positive electrode slurry and mixed to prepare a cathode active material in which high-nickel material was coated with LFMP. Then, a cathode active material was applied to an aluminum foil current collector, baked at 100°C, and then cold pressed, trimmed, cut, slit, and tab-welded to produce a positive electrode / positive electrode sheet for a lithium battery. In Experimental Example 16, the positive electrode was further combined with a negative electrode manufactured in the following manner (however, the present application is not limited to this procedure) to manufacture and test a lithium battery. The negative electrode manufacturing procedure includes the following: At least 5 wt% of the composite silicon high-entropy material and graphite were mixed to prepare the anode active material, which accounted for 95 wt% of the total anode weight. Single-walled carbon nanotubes were added to the anode slurry to achieve a single-walled carbon nanotube solids content of 0.1 wt%. PVDF was added to the anode slurry to achieve a PVDF solids content of 4.9 wt%. The anode slurry was dissolved in NMP as the solvent system, stirred uniformly, and then coated onto copper foil to produce the anode electrode. After baking at 110°C, the anode electrode / anode sheet for lithium batteries was fabricated by cold pressing, trimming, cutting, slitting, and tab welding. The above positive electrode sheet and negative electrode sheet were used as a positive electrode plate and a negative electrode plate, respectively, and a test lithium secondary battery was assembled in the following manner. A positive electrode plate and a negative electrode plate were prepared, and a separator was placed between them to define a storage area. The positive and negative electrodes were alternately stacked, and after adding an electrolyte solution, the battery was placed in an aluminum plastic film, packaged, activated, and tested. Figure 12 shows the results of a needle puncture test on the lithium secondary batteries fabricated in Experimental Example 16 and Comparative Example 2. In Comparative Example 2, a high-nickel positive electrode material, superconducting carbon (Super-P) as a conductive agent, and polyvinylidene fluoride (PVDF) as a binder were uniformly mixed in a mass ratio of 97:1.5:1.5 and dissolved in N-methyl-2-pyrrolidone (NMP) to prepare a positive electrode slurry with a predetermined viscosity. This slurry was then applied to an aluminum foil current collector, baked at 110°C, cold-pressed, trimmed, slit, and tab-welded to produce a lithium battery positive electrode sheet. Additionally, at least 5 wt% nanosilicon powder and graphite were mixed to prepare an anode active material, which accounted for 95 wt% of the total anode weight. To the negative electrode slurry, single-walled carbon nanotubes with a solid content of 0.1 wt% and a PVDF binder with a solid content of 4.9 wt% were added, and the whole was dissolved in NMP, stirred uniformly, and then coated on copper foil to produce an anode electrode. After baking at 110°C, cold pressing, trimming, cutting, slitting, and tab welding were performed to produce a negative electrode sheet for a lithium battery. In Comparative Example 2, a lithium secondary battery with a structure similar to that of the lithium secondary battery in the above experimental example was manufactured using the above lithium battery positive electrode sheet and lithium battery negative electrode sheet and an aluminum plastic case, which was then packaged, activated, and tested. In other words, in the lithium battery manufactured according to the manufacturing flow of Comparative Example 2, the cathode active material of the positive electrode / cathode electrode does not contain the cathode composite material described in the above experimental example. 12, in a needle puncture test of the lithium batteries manufactured in Experimental Example 16 and Comparative Example 2, no smoke was observed in Experimental Example 16 (right side of FIG. 12), but smoke was generated and damage was observed in Comparative Example 2 (left side of FIG. 12). The test conditions for the needle puncture test and the puncture results for the control group (Comparative Example 2) are shown in FIG. 13.

[0099] Step flow of Experimental Example 17: High-nickel positive electrode material, carbon nanotubes, SBR binder, and CMC thickener were uniformly mixed in a mass ratio of 95.5:0.5:2:2 and dissolved in deionized water to prepare a positive electrode slurry with a predetermined viscosity. This was then added to a nano-LFMP slurry with a solid content of 40% dispersed in water as a solvent in a total amount of 5% of the solid content of the original positive electrode slurry, and mixed to prepare a cathode active material in which high-nickel material was coated with LFMP. Then, a cathode active material was applied to an aluminum foil current collector, baked at 100°C, and then cold pressed, trimmed, cut, slit, and tab-welded to produce a positive electrode / positive electrode sheet for a lithium battery. In Experimental Example 17, the above positive electrode was further combined with a negative electrode manufactured in the following manner (however, the present application is not limited to this procedure) to manufacture and test a lithium battery. The negative electrode manufacturing procedure includes the following: The anode active material was prepared by mixing at least 5 wt% of a composite silicon high-entropy material and graphite. The anode active material accounted for 95 wt% of the total anode weight. Single-walled carbon tubes and graphene were added to the anode slurry so that the solid contents of the single-walled carbon tubes and graphene were 0.1 wt%, respectively. SBR was added to the anode slurry so that the SBR solid content was 2.5 wt%. CMC was added as a thickener at 2.4 wt%. The anode slurry was dissolved in deionized water as the solvent system, stirred uniformly, and then coated on copper foil to produce the anode electrode. After baking at 100°C, the anode electrode / anode sheet for lithium batteries was produced by cold pressing, trimming, cutting, slitting, and tab welding. The above positive electrode sheet and negative electrode sheet were used as a positive electrode plate and a negative electrode plate, respectively, and a test lithium secondary battery was assembled in the following manner. A positive electrode plate and a negative electrode plate were prepared, and a separator was placed between them to define a storage area. The positive and negative electrodes were alternately stacked, and after adding an electrolyte solution, the battery was placed in an aluminum plastic film, packaged, activated, and tested.

[0100] Step flow of Experimental Example 18: High-nickel positive electrode material NCM811, binder PVDF, and multi-walled carbon nanotubes (4% MWCNT) were uniformly mixed in a solid mass ratio of 87.3:2:1, and dissolved in the organic solvent NMP to prepare a positive electrode slurry with a predetermined viscosity. After that, the LFMP slurry prepared according to Experimental Example 10 was added to the positive electrode slurry in a total amount of 9.7% of the solid content of the original positive electrode slurry, and mixed. A cathode composite material in which the positive electrode material was coated with LFMP was prepared as the cathode active material. The cathode active material was then applied to an aluminum foil current collector, baked at 110°C, and cold pressed, trimmed, cut, slit, and tab welded to produce a positive electrode / positive electrode sheet for a lithium battery. In Experimental Example 18, the positive electrode was further combined with a negative electrode manufactured in the following manner (although the present application is not limited to this procedure) to manufacture and test a lithium battery. The negative electrode manufacturing procedure includes the following: The anode active material was prepared by mixing at least 5 wt% of a composite silicon high-entropy material and graphite. The anode active material accounted for 95 wt% of the total anode weight. Single-walled carbon nanotubes (SWCNTs) were added to the anode slurry to achieve a solids content of 0.1 wt%. PVDF was added to the anode slurry to achieve a solids content of 4.9 wt%. The anode slurry was dissolved in NMP as the solvent system, stirred uniformly, and then coated onto copper foil to produce the anode electrode. After baking at 110°C, the anode electrode / anode sheet for lithium batteries was fabricated by cold pressing, trimming, cutting, slitting, and tab welding. The above positive electrode sheet and negative electrode sheet were used as a positive electrode plate and a negative electrode plate, respectively, and a test lithium secondary battery was assembled in the following manner. The positive and negative electrodes were stacked alternately, and a separator was placed between them to define a storage area. After adding an electrolyte solution, the electrodes were placed in an aluminum plastic film, packaged, activated, and tested.

[0101] Step flow of Experimental Example 19: High-nickel positive electrode material NCM811, binder PVDF, and multi-walled carbon nanotubes (4% MWCNT) were mixed in a solid mass ratio of 92.15:2:1 and dissolved in the organic solvent NMP to prepare a positive electrode slurry with a predetermined viscosity. After that, the LFMP slurry prepared according to Experimental Example 10 was added to the positive electrode slurry in a total amount of 4.85% based on the solid content of the original positive electrode slurry, and mixed. A cathode composite material in which the positive electrode material was coated with LFMP was prepared as the cathode active material. The cathode active material was then applied to an aluminum foil current collector, which was then baked at 110°C, followed by cold pressing, trimming, cutting, slitting, and tab welding to produce a positive electrode / positive electrode sheet for a lithium battery. In Experimental Example 19, the above positive electrode was further combined with a negative electrode similar to that of Experimental Example 18 to produce a lithium battery, which was then tested. The process for preparing the negative electrode and the method for arranging the lithium battery can be found in the above Experimental Examples, and will not be described in detail here.

[0102] Step flow of Experimental Example 20: Lithium cobalt oxide positive electrode material LCO, binder PVDF, and multi-walled carbon nanotubes (4% MWCNT) were uniformly mixed in a solid mass ratio of 92.15:2:1 and dissolved in NMP organic solvent to prepare a positive electrode slurry with a predetermined viscosity. Then, LFMP slurry prepared according to Experimental Example 10 was added to the positive electrode slurry in a total amount of 4.85% based on the solid content of the original positive electrode slurry, and mixed to prepare a cathode composite material in which the positive electrode material was coated with LFMP as the cathode active material. The cathode active material was then applied to an aluminum foil current collector, which was then baked at 110°C, followed by cold pressing, trimming, cutting, slitting, and tab welding to produce a positive electrode / positive electrode sheet for a lithium battery. In Experimental Example 20, the above positive electrode was further combined with a negative electrode similar to that in Experimental Example 18 to produce a lithium battery and perform testing. The procedure for preparing the negative electrode and the method for arranging the lithium battery can be found in the above Experimental Examples, and will not be described in detail here.

[0103] [Table 4]

[0104] According to the data of each experimental example disclosed in Table 4 above, it was found that the silicon anode material composite high-entropy material prepared by modifying silicon powder in different positive and negative electrode systems, such as a water solvent system or an NMP solvent system, was superior to the silicon powder of Comparative Example 1 in terms of conductivity, capacity, first cycle efficiency, and efficiency after multiple cycles.

[0105] [Table 5]

[0106] Table 5 above summarizes the expansion property data for Experimental Examples 12 to 17 and Comparative Example 1. The data for each experiment disclosed in Table 5 above demonstrates that the silicon anode material composite high-entropy material produced by modifying silicon powder further reduces the expansion of the silicon anode. Furthermore, by combining LFMP with a high-nickel cathode material and applying it to a manufacturing process using pure water as a solvent, environmental protection requirements can be met while maintaining the safety of lithium batteries, providing the market with safe, high-capacity batteries.

[0107] [Table 6]

[0108] Table 6 summarizes the material property data of Experimental Examples 15 to 17 and Comparative Examples 3 to 5, and the preparation methods of Comparative Examples 3 to 6 are as follows.

[0109] Comparative Example 3: LFMP was used as the positive electrode material, and was uniformly mixed with PVDF binder and multi-walled carbon nanotubes (4% MWCNT) in a solid mass ratio of 97:2:1. The mixture was then dissolved in NMP, an organic solvent, to prepare a positive electrode slurry with a predetermined viscosity. A positive electrode / positive electrode sheet was then manufactured from this slurry.

[0110] Comparative Example 4: High-nickel positive electrode material NCM811, binder PVDF, and multi-walled carbon nanotubes (4% MWCNT) were uniformly mixed in a solids mass ratio of 38.8:2:1 and dissolved in an organic solvent NMP to prepare a positive electrode slurry with a predetermined viscosity. LFMP powder that had not been treated in Experimental Examples 7 to 11 above was then added to the positive electrode slurry in a total amount of 58.2% of the solids content of the original positive electrode slurry, and a positive electrode / positive electrode sheet was manufactured using this.

[0111] Comparative Example 5: High-nickel positive electrode material NCM811, binder PVDF, and multi-walled carbon nanotubes (4% MWCNT) were uniformly mixed in a solid mass ratio of 77.6:2:1, and the mixture was dissolved in an organic solvent NMP to prepare a positive electrode slurry with a predetermined viscosity. LFMP powder that had not been treated in the above Experimental Examples 7 to 11 was then added to the positive electrode slurry in a total amount of 19.4% of the solid content of the original positive electrode slurry to produce a positive electrode / positive electrode sheet. Comparative Example 6: High-nickel cathode material NCM811, binder PVDF, and multi-walled carbon nanotubes (4% MWCNT) were uniformly mixed in a solid mass ratio of 97:2:1, and dissolved in the organic solvent NMP. A cathode slurry with a predetermined viscosity was prepared without adding any LFMP, and a cathode electrode / cathode sheet was manufactured from the slurry.

[0112] From Table 6 above, it can be seen that the positive electrodes manufactured in Experimental Examples 10 to 12, which were performed based on the preparation method of the lattice stabilized material shown in FIG. 7, exhibited better electrode density than the positive electrode manufactured using LFMP (Comparative Example 3) or the positive electrode manufactured by adding untreated LFMP powder to the high-nickel positive electrode material NCM811 (Comparative Example 4).

[0113] Figure 14 compares scanning electron microscope images of the positive electrodes manufactured in Experimental Example 19 and Comparative Example 6. When the microsurface morphology of the positive electrodes manufactured in Experimental Example 19 and Comparative Example 6 was observed using a scanning electron microscope (SEM), a particle distribution mainly consisting of NCM811 was observed in the electrode manufactured based on Comparative Example 6. On the other hand, in the electrode manufactured based on Experimental Example 19, it was clearly observed that nano-sized LFMP particles were uniformly coated on the surface layer of NCM811, and calibration of the Fe and P elements in LFMP confirmed that LFMP was uniformly distributed on the surface layer of NCM811.

[0114] 15 is a photograph showing a needle puncture test performed on a lithium battery manufactured according to Comparative Example 6. In this test, the lithium battery manufactured according to Comparative Example 6 was activated, aged, and capacity-graded, and then charged to 100% electricity. As a result of the needle puncture test, fire and smoke were generated.

[0115] 16 is a photograph showing a needle puncture test performed on the lithium battery manufactured according to Comparative Example 5. In this test, the lithium battery manufactured according to Comparative Example 5 was subjected to activation, aging, and capacity grating, and then charged to 100% electricity. As a result of the needle puncture test, no fire occurred, but smoke was emitted.

[0116] From the above, Comparative Example 5, which contains a small weight percentage of untreated LFMP powder, and Comparative Example 6, which does not contain any untreated LFMP powder, have electrode densities similar to those of Experimental Examples 10 to 12. However, the results of the needle puncture tests in FIGS. 15 and 16 show that lithium batteries manufactured using only the high-nickel positive electrode material NCM811 have a risk of fire, and that adding an insufficient amount of untreated LFMP powder does not improve safety.

[0117] Figure 17 is a photograph showing a needle puncture test performed using a lithium battery manufactured according to Experimental Example 18. In this test, the lithium battery manufactured according to Experimental Example 18 was activated, aged, and capacity grated, and then charged to 100% electricity. As a result of the needle puncture test, no fire or smoke was generated, and the battery was relatively safe.

[0118] The present application is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present application also includes embodiments obtained by appropriately combining the technical means disclosed in different embodiments. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0119] It should be understood by those skilled in the art that any numerical value described in this application does not limit the application to the specific numerical value alone, and that as long as there is an allowable error in each numerical value / composition ratio and the results / functions that each experimental example is trying to achieve are not significantly affected, all values ​​that approximate the disclosed numerical range can be considered to belong to the disclosed range of this application. [Explanation of symbols]

[0120] 10. Lithium secondary battery 11 Cathode 110 cathode material layer 111 Cathode current collector 12 Separator 13 Anode 130 anode material layer 131 Anode current collector 200 Composite materials 210 silicon particles 220 Ceramic Materials 230 Conductive Carbon M1 anode active material M2 conductive material M3 Binder NCT carbon nanotubes S110~S140 Step flow of the cathode active material preparation method S210-S240, S310-S370 Step flow of the anode active material preparation method S410~S430 Step flow of the preparation method of lattice stabilized materials

Claims

1. A lithium secondary battery, A separator; a cathode disposed on one side of the separator and including a cathode active material, the cathode active material including a first composite material based on a high nickel material; an anode disposed on an opposite side of the separator and including an anode active material, the anode active material including a second composite material of silicon particles and a high-entropy material; A lithium secondary battery, characterized in that the high-entropy material is composed of at least five types of elements, and the proportion of each of the elements in the high-entropy material is 50% or less.

2. 2. The lithium secondary battery according to claim 1, wherein the high-nickel material has nickel as a central metal in an electrochemical oxidation-reduction reaction, and the mole ratio of nickel atoms in the high-nickel material exceeds 50%.

3. 3. The lithium secondary battery according to claim 2, wherein the high-nickel material comprises a material based on a lithium nickel oxide structure.

4. The materials based on the lithium nickel oxide structure include lithium nickel cobalt aluminum oxide (LiNi １－ｘ－ｙ Co ｘ Al ｙ O ２ , NCA), and lithium nickel manganese cobalt oxide (LiNi １－ｘ－ｙ Mn ｘ Co ｙ O ２ (NMC) or LiNi １－ｘ－ｙ Co ｘ Mn ｙ O ２ 4. The lithium secondary battery according to claim 3, wherein the lithium secondary battery comprises at least one of:

5. 3. The lithium secondary battery according to claim 2, wherein the first composite material further comprises a lattice stabilizing material formed on at least a portion of a surface of the high nickel material.

6. The lattice stabilizing material is lithium iron manganese phosphate (LiFe １－ｘ Mn ｘ P.O. ４ , LFMP) and lithium iron phosphate (LiFePO ４ 5. The lithium secondary battery according to claim 4, wherein the lithium secondary battery comprises at least one of the following:

7. 7. The lithium secondary battery according to claim 6, wherein the lattice stabilizing material is an LFMP slurry, and the LFMP slurry is prepared with a ratio of usage amount satisfying the following range: [Equation 2] (Here, A, B, C, D, and E are the amounts of PVP, PVDF, phosphazene, NMP, and LFMP used, respectively.)

8. The lithium secondary battery according to claim 1 , wherein the first composite material further comprises at least one of a conductive material, a binder, and a filler.

9. 2. The lithium secondary battery according to claim 1, wherein the high-entropy material includes at least one of a high-entropy alloy, a high-entropy oxide, a high-entropy polymer compound, and a high-entropy ceramic.

10. In the second composite material, the high entropy material is formed in at least one region on the surface of the silicon particle, and the chemical formula of the high entropy material is Si １－（ｘ＋ｙ＋ｍ＋ｎ＋ｚ） (M ｘ N ｙ A ｍ B ｎ X ｚ ) O ｐ (wherein p=0.1 to 2, M, N, A, and B are each any one of monovalent to tetravalent elements, M, N, A, and B have different valences, and X is a transition metal element or an element other than monovalent to tetravalent elements).

11. 11. The lithium secondary battery according to claim 10, wherein x, y, m, n, and z are each 0.2 or less.

12. 11. The lithium secondary battery of claim 10, wherein M comprises one of lithium and sodium, N comprises one of beryllium, magnesium, calcium, strontium, and barium, A comprises one of boron, aluminum, gallium, and indium, and B comprises one of carbon, silicon, germanium, tin, and lead.

13. 11. The lithium secondary battery according to claim 10, wherein the second composite material further includes at least one of a conductive material, a binder, and a filler.

14. A method for manufacturing a lithium secondary battery, comprising: fabricating a positive electrode using the cathode active material; fabricating a negative electrode using the anode active material; stacking the positive electrode, separator, and negative electrode alternately and placing the stack in an electrolyte solution; and encapsulating the positive electrode, the separator, and the negative electrode in the electrolyte solution in a plastic film; The cathode active material is prepared from a first composite material based on a high-nickel material, and the anode active material is prepared from a second composite material consisting of silicon particles and a high-entropy material; A method for manufacturing a lithium secondary battery, characterized in that the high-entropy material is composed of at least five types of elements, and the proportion of each of the elements in the high-entropy material is 50% or less.

15. 15. The method for producing a lithium secondary battery according to claim 14, wherein the high-nickel material has nickel as a central metal in an electrochemical oxidation-reduction reaction, and the molar ratio of nickel atoms in the high-nickel material exceeds 50%.

16. The cathode active material preparation process includes: adding at least one of water, an aqueous solution, and an organic solvent to a reaction vessel as a solvent system; placing the high nickel material in the reaction vessel and mixing with the solvent system; adding a lattice stabilizing material to the solvent system; mixing the high-nickel material and the lattice-stabilizing material in the solvent system to produce the first composite material having the lattice-stabilizing material attached to at least a portion of the surface structure of the high-nickel material.

17. 17. The method for producing a lithium secondary battery according to claim 16, wherein the lattice stabilizing material includes at least one of lithium iron manganese phosphate and lithium iron phosphate.

18. The lattice stabilizer material is adding a dispersant to the second organic solvent; adding powdered lithium iron manganese phosphate to the second organic solvent containing the dispersant to form a mixed material; and grinding the mixed material to produce a lattice-stabilized material in a slurry form.

19. The procedure for preparing the anode active material is as follows: mixing water and an organic solvent in a reaction vessel; placing a silicon material in the reaction vessel and contacting it with the organic solvent; adding precursors of the constituent elements of the high-entropy material to the organic solvent; mixing the precursor and the silicon material in the organic solvent to produce the second composite material comprising silicon particles and the high-entropy material; The chemical formula of the high entropy material is Si １－（ｘ＋ｙ＋ｍ＋ｎ＋ｚ） (M ｘ N ｙ A ｍ B ｎ X ｚ ) O ｐ (p=0.1 to 2; M, N, A, and B are each any one of monovalent to tetravalent elements; M, N, A, and B have different valences; and X is a transition metal element or an element other than monovalent to tetravalent elements).

20. The procedure for preparing the anode active material is as follows: drying the second composite material at a first temperature; 20. The method for producing a lithium secondary battery according to claim 19, further comprising: heating the dried second composite material at a second temperature in an inert environment to produce the second composite material in powder form.

21. 21. The method for manufacturing a lithium secondary battery according to claim 20, wherein the first temperature is between 50°C and 150°C.

22. 22. The method for manufacturing a lithium secondary battery according to claim 21, wherein the first temperature is between 900 and 1500°C.

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