Prelithiated and carbon-encapsulated silicon-based anode materials and methods for fabrication using optical electromagnetic energy

Abstract

A method for producing an anode material for a lithium secondary battery using prelithiation and irradiation with light electromagnetic energy, and an anode material for a lithium secondary battery are disclosed. The method includes the steps of mixing an active material, a polymer, and a lithium salt in a solvent to form a liquid mixture, converting the liquid mixture into droplets, drying the droplets to form a powder, and applying optical electromagnetic energy to the resulting dried powder.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an anode material for lithium secondary batteries such as lithium ion batteries, lithium metal batteries, lithium sulfur batteries, lithium air batteries, etc. In particular, the present invention relates to a method for manufacturing an anode material for lithium secondary batteries that can encapsulate an active material while prelithiating it using irradiation with light electromagnetic energy.

[0002] The present invention also relates to prelithiated and encapsulated anode materials for lithium secondary batteries. [Background technology]

[0003] Demand for lithium secondary batteries, such as lithium-ion batteries, is increasing due to their wide range of applications, from small and portable electronic products to large electric vehicles. The shift from fossil fuel-powered vehicles to electric vehicles is becoming more visible, which is driving interest in high-performance lithium secondary batteries. Various research efforts are underway to achieve higher capacity, longer life, faster charging, and greater safety for lithium secondary batteries. One of these efforts is the development of electrodes that use active materials with higher energy density than existing batteries.

[0004] Silicon (Si), with a theoretical capacity of 3,600 mAh / g, has attracted attention as a candidate anode active material for lithium-based batteries due to its high energy density. However, silicon is known to have a high volume expansion rate during repeated lithiation processes. These rapid volume changes can lead to the crushing and exfoliation of the active material, resulting in the loss of electrode integrity and electrical insulation, and degrading battery performance.

[0005] To solve the problem of the volume expansion rate of these active materials, several ideas have been proposed: To suppress the volume change of the active material or to provide sufficient space, the active material can be encapsulated with a hard outer shell to allow for charge-discharge cycles without physical stress.

[0006] Some prior art documents have proposed creating a nanoporous structure in the active material or in a shell surrounding the active material to increase the reactive surface area for ion diffusion, but these techniques involve high economic or environmental costs associated with the procedures, which ultimately increase the production costs of battery products.

[0007] Furthermore, silicon-based anode materials have lower initial efficiencies than graphite-based anode materials due to the loss of lithium ions to an irreducible state after reacting with the silicon surface. Prelithiation has been proposed as a solution to this problem, but currently requires complex processes, such as applying an anode slurry, drying it, and then prelithiating it to prevent reactions with materials in the slurry, such as binders and graphite. Furthermore, these processes are divided into two steps, such as encapsulating the silicon, and the subsequent prelithiation process, which increases the overall process complexity. Summary of the Invention [Problem to be solved by the invention]

[0008] Another problem to be solved by the present invention is to provide a method for producing an anode material for a lithium secondary battery, which is capable of prelithiating and encapsulating an active material.

[0009] Another problem to be solved by the present invention is to provide a prelithiated and encapsulated anode material for a lithium secondary battery. [Means for solving the problem]

[0010] To address the above-mentioned issues, the present invention provides a method for manufacturing an anode material for a lithium secondary battery by encapsulating and prelithiating an anode active material with a large volume expansion coefficient, such as silicon. The present invention uses the application of light electromagnetic energy in conjunction with droplet drying of the powder. The light electromagnetic energy used in the present invention is intense pulsed light (IPL) or microwaves. Both IPL and microwaves simplify the heat transfer process, resulting in less heat loss than conventional heating methods and enabling the transfer of high energy in a short period of time.

[0011] More specifically, a method for preparing an anode material for a lithium secondary battery according to an embodiment of the present invention includes the steps of: mixing an active material, a polymer, and a lithium salt in a solvent to form a liquid mixture; converting the liquid mixture into droplets and drying the droplets to form a powder; and applying optical electromagnetic energy to the resultant dried powder to prelithiate the active material and at least partially carbonize the polymer.

[0012] IPL, a type of photoelectromagnetic energy application, is performed by irradiating high-power xenon light in the wavelength range of 500-1200 nm. The carbonization effect of the polymer can vary depending on the IPL application time. For example, when IPL is applied for a few milliseconds or less, the carbonization effect is primarily concentrated on the outer shell, resulting in a shell structure with a hard, carbonized outer shell and a soft, inner polymer shell. When IPL is applied for, say, 10 milliseconds or more, the entire polymer is carbonized, resulting in a shell made entirely of carbon. The carbonized outer shell or carbonized shell provides electrical conductivity and structural support along the solid electrolyte interface (SEI). The soft polymer inner layer is elastic, preventing the active material from being crushed while providing space for the active material to expand in volume without shattering.

[0013] Depending on the power or time of microwave application, a partially or fully carbonized shell can be formed. Microwaves refer to optical electromagnetic waves in the wavelength range of 1 to 1000 mm, which directly raise the temperature of an object using dipolar polarization or interfacial polarization, or indirectly transfer heat by creating plasma around the material.

[0014] The heat generated during the polymer carbonization process by IPL or microwave application can promote the reaction between the lithium salt and silicon, resulting in the lithiation of silicon.

[0015] The active material may contain at least one of silicon and silicon oxide.

[0016] The active material may be surface-pretreated by applying optical electromagnetic energy, which may burn impurities contained in the active material in a short time, form a stable oxide layer on the surface of the active material, and change the surface energy of the active material, thereby increasing its wettability to the electrolyte.

[0017] The lithium salt may include one or more of Li2O, LiOH, LiO2CH, Li2CO3, Li2C2O4, Li3C6H5O7, LiNO3, LiCl, LiF, or a lithium-functionalized polymer such as lithium citrate (Li3H6H5O7).

[0018] The solvent may include an aqueous solvent or an organic solvent.

[0019] Converting the liquid mixture into droplets and drying the droplets to a powder may include spraying the liquid mixture into an air flotation chamber to form droplets, and circulating and drying the droplets within the air flotation chamber using a heater.

[0020] Light electromagnetic energy can be applied within the air suspension chamber to accelerate the drying process or for carbonization and prelithiation.

[0021] In another example, the powder drying step may include spraying the liquid mixture into a chamber to generate droplets, flash-freezing the droplets in the chamber using nitrogen gas to form frozen droplets, and vacuum-drying the frozen droplets to form a powder.

[0022] Another aspect of the present invention provides an anode material for a lithium secondary battery, the anode material for a lithium secondary battery comprising: a lithiated active material; and a shell layer surrounding the lithiated active material and having pores formed therein; the lithiated active material comprising a lithium-silicon alloy and a lithium silicate layer surrounding the lithium-silicon alloy; and the shell layer having an outermost layer formed of carbon. [Effects of the Invention]

[0023] The present invention provides a novel method for encapsulating an active material using prelithiation and irradiation with electromagnetic light energy. The method for manufacturing an anode material for a lithium secondary battery according to the present invention allows for simultaneous prelithiation and encapsulation of the active material using irradiation with electromagnetic light energy.

[0024] This, and the method for producing an anode material for a lithium secondary battery according to the present invention, allows for prelithiation in the form of a powder anode material before fabrication of an anode electrode by prelithiation prior to encapsulation of the active material, while providing an electrically conductive, hard protective shell.

[0025] In particular, the present invention uses a pre-lithiated anode active material, which increases the initial coulombic efficiency (ICE) during battery assembly. This minimizes the amount of anode consumed due to irreversible capacity, reducing the anode ratio during anode design and increasing capacity, thereby increasing the battery's energy density. The silicon oxide film found on silicon exposed to air transforms into a lithium silicate film, preventing unwanted chemical reactions with the lithiated silicon during subsequent anode preparation and battery manufacturing processes. The hard carbon shell covers the volume of the active material expanded by lithiation, preventing damage to the active material due to silicon expansion during subsequent charge and discharge processes. Because the anode material disclosed herein is not a mixture of graphite and silicon, there is no need to use a lithiated solution that does not react with graphite, which is expensive and requires a complex manufacturing process, due to concerns about graphite oxidation or carbon chain breakdown, as in conventional methods. [Brief explanation of the drawings]

[0026] Referring to the drawings, various aspects of the present invention are shown in detail by way of example and not by way of limitation.

[0027] [Figure 1] 1 is a diagram schematically illustrating a method for producing an anode material for a lithium secondary battery according to the present invention. [Figure 2] FIG. 1 is a schematic diagram illustrating an example of an electrospray method. [Figure 3] FIG. 10 illustrates a process for drying droplets of encapsulated active material in an air flotation chamber using an IR heater. [Figure 4] FIG. 10 is a schematic diagram illustrating the application of IPL to powdered encapsulated active material in an air flotation chamber. [Figure 5] 1 is a diagram illustrating a charging and discharging process of an anode material for a lithium secondary battery according to the present invention; [Figure 6]FIG. 1 is a schematic diagram of an example of an apparatus for drying droplet-encapsulated active materials using the spray freeze drying technique. DETAILED DESCRIPTION OF THE INVENTION

[0028] The following description and the embodiments described herein are provided as examples of principles of the present invention in its various forms. These embodiments are not intended to limit the present invention in its various forms, but are provided for illustrative purposes. Like reference numerals refer to like parts throughout the description and drawings. The drawings are not necessarily to scale, and in some cases proportions may be exaggerated to more clearly depict particular features.

[0029] The method for manufacturing an anode material for a lithium secondary battery according to the present invention provides a method for manufacturing an anode material for a lithium secondary battery, which can minimize negative side effects such as volume change or high internal stress in the anode of a lithium secondary battery such as a lithium ion battery, a lithium metal battery, a lithium air battery, a lithium sulfur battery, or a lithium all-solid-state battery, fracture, crushing, peeling, electronic insulation from the conductive agent, instability of the SEI, and the resulting consumption of the electrolyte and loss of the battery's energy capacity.

[0030] In addition, the method for manufacturing an anode material for a lithium secondary battery according to the present invention involves encapsulating and prelithiating an anode active material having a large volume expansion coefficient, such as silicon, and the method involves drying the active material in the form of droplets and applying light electromagnetic energy.

[0031] FIG. 1 is a diagram schematically illustrating a method for producing an anode material for a lithium secondary battery according to the present invention.

[0032] Referring to FIG. 1, the method for preparing an anode material for a lithium secondary battery according to the present invention includes the steps of forming a liquid mixture, drying the droplets, prelithiation by applying light electromagnetic energy, and polymer carbonization.

[0033] In the liquid mixture formation step, the active material 110, the lithium salt 120, and the polymer 130 are mixed in a solvent to form a liquid mixture.

[0034] The liquid mixture used in the method for manufacturing an electrode for a lithium secondary battery according to the present invention includes an active material, a lithium salt, a polymer, and a solvent. For example, the liquid mixture may contain 80 to 95 parts by weight of the active material, 1 to 10 parts by weight of the lithium salt, and 1 to 10 parts by weight of the polymer, per 100 parts by weight of the solids (excluding the solvent) of the liquid mixture. The contents of the active material, lithium salt, and polymer may vary depending on the types of materials used. Meanwhile, the solvent may be used in an appropriate amount depending on the type of polymer used, for example, 50 to 100 parts by weight per 100 parts by weight of the solids.

[0035] The solvent may include aqueous solvents (water, methanol, ethanol, etc.) and organic solvents. Li2O converts to LiOH in water, but when using a methanol or ethanol solution, it remains as Li2O and reacts. This means that the reaction rate is faster than that of LiOH. Silicon can be rapidly oxidized in aqueous solvents. However, organic solvents can prevent some silicon from rapidly oxidizing in aqueous solvents and generating hydrogen gas.

[0036] The lithium salt may include at least one of Li2O, LiOH, LiO2CH, Li2CO3, Li2C2O4, Li3C6H5O7, LiNO3, LiCl, LiF, or a lithium-functionalized polymer.

[0037] The active material may contain at least one of silicon and silicon oxide.

[0038] The active material may be pre-surface-treated by applying optical electromagnetic energy, which can burn impurities contained in the active material in a short time, form a stable oxide layer on the surface of the active material, and change the surface energy of the active material, thereby increasing its wettability to the electrolyte.

[0039] Meanwhile, the application of the photo-electromagnetic energy causes the lithium salt and the active material to react with each other, and the gas products of the reaction escape to the outside, generating pores that allow lithium ions to diffuse into the core active material.

[0040] Any polymer can be used without limitation as long as it can encapsulate the active material. For example, polymers applicable to the present invention may include at least one of polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), poly(methyl methacrylate) (PMMA), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), polydiacetylene (PDA), polypropylene (PP), polystyrene (PS), polyurethane (PU), polyethylene oxide (PEO), polyethylene terephthalate (PET), styrene-ethylene-butylene-styrene (SEBS), glycerol, sucrose, cellulose, lignin, polyvinylidene fluoride (PVDF), polyvinylidene fluoride trifluoroethylene (PVDF-TRFE), polyaniline, and parylene C, but are not limited thereto. When two or more types of polymers are contained, the polymers can be polymers with different boiling points, or polymers that form double network hydrogels, such as a combination of carboxymethyl cellulose (CMC) and polyacrylic acid (PAA).

[0041] In another example, the polymer can be an organosilicon polymer containing the anode active material components therein, such as polysiloxane, polysilsesquioxane, polycarbosiloxane, polyborosilane, polysilicarbodiimide, etc. The anode active material components within the polymer can provide additional energy capacity to the electrode and can provide an additional prelithiation source. Carbonization of the organosilicon polymer containing the anode active material components can form a shell composed of SiOC (silicon oxycarbide), SiC (silicon carbide), SiBCN (silicon boron carbon nitride), SiCN (silicon carbon nitride), etc.

[0042] Meanwhile, photo-electromagnetic energy can be applied during the mixture formation step, thereby partially prelithiating the active material and carbonizing the polymer.

[0043] Furthermore, depending on the type of lithium salt and the polymer used for encapsulation, a reaction between the polymer and the lithium salt, such as LiOH, LiCl, or LiF, may occur. In this case, the lithium ions remain in the polymer as lithium metal and react with the anode active material upon application of energy. However, the reaction between the lithium metal and the anode active material may be slower than the reaction between the lithium salt and the anode active material. Furthermore, the reaction between the lithium metal and the anode active material may require the application of more energy.

[0044] In the droplet drying step, the liquid mixture is sprayed using various methods, such as atomization, to form droplets, and the solvent is then removed by droplet drying. The droplet drying step can be performed, for example, in an air flotation chamber, where the droplets can suspend and circulate while drying into a powder. The powder material formed by the droplet drying step can be composed of an active material 110 and a polymer layer 130 surrounding the active material, as shown in FIG. 1 , but the polymer layer 130 may contain a lithium salt 120. A small oxide layer 115 may be formed on the surface of the active material 110.

[0045] Specifically, the droplet drying step may include spraying the liquid mixture into an air-suspended chamber using a method such as Collison nebulization, piezoelectric spraying, ultrasonic spraying, or electrospraying to generate droplets, for example, having a size of several hundred nanometers to several micrometers, and drying the droplets while suspending and circulating them in the air-suspended chamber using a heater, as in the example shown in FIG. 3, or rapidly freezing them using nitrogen gas followed by vacuum drying, as in the example shown in FIG. 6.

[0046] FIG. 2 is a schematic diagram of an example of an electrospray method.

[0047] To produce a powder of individually encapsulated active materials, particulates of the mixture must be formed prior to drying and application of energy.

[0048] FIG. 2 shows that the active material is sprayed into droplets 210 encapsulated in a polymer binder by electrospray using, for example, a Collison atomizer 201 .

[0049] The Collison nebulizer, first developed by KR May in 1972 [May 1972], has long been recognized as an aerosolization technique for a variety of liquids. Air in the Collison nebulizer moves at high speed through the nebulizer's small orifice, then draws in the liquid from the nebulizer jar, breaking it into small droplets. The nebulized liquid then impacts the jar wall, creating even smaller droplets. Larger particles are removed from the aerosol by a curved discharge tube.

[0050] Unlike the example shown in Figure 2, both piezoelectric atomizers and ultrasonic sprayers use piezoelectric transducers to generate atomized particles. High-frequency voltage applied to the transducer generates high-frequency vibrations. In ultrasonic atomizers, a liquid is placed on the surface of a piezoelectric transducer, which vibrates the liquid. The vibrations create a capillary waveform (standing wave) within the liquid, from which small droplets are released in the form of an aerosol. In ultrasonic sprayers, the sample principle is applied because the liquid is atomized when it reaches the surface of a vibrating nozzle. The size of the atomized particles varies depending on the applied vibration frequency. To generate nanometer particles, vibrations at frequencies in the megahertz (MHz) range are required. Due to geometric constraints, ultrasonic atomizers more commonly operate in the megahertz range, further limiting the operating frequency of atomizers to tens of kilohertz.

[0051] FIG. 3 shows the process of drying the droplet-encapsulated active material in an air flotation chamber using an IR heater.

[0052] The droplet drying system shown in FIG. 3 includes a transparent cylindrical chamber 310, an atom nozzle 320 for providing droplets of encapsulated active material 301 to be dried, an infrared heater 330 for applying heat 335 to the encapsulated active material, and a blower 340 for keeping the encapsulated active material suspended within the transparent cylindrical chamber 310.

[0053] In the droplet drying system shown in FIG. 3, the encapsulated active material 301 sprayed by the atomic nozzle 320 is continuously suspended in air by circulating air through a blower 340 in a sealed transparent cylindrical chamber 310, and can be irradiated with an infrared (IR) heater 330 for drying.

[0054] 4, photo-electromagnetic energy can be applied to the air suspension chamber. This application of photo-electromagnetic energy can cause prelithiation of the active material and polymer carbonization. This step can replace or be separate from the photo-electromagnetic energy application step described below.

[0055] In the prelithiation and polymer carbonization step by applying photoelectromagnetic energy, photoelectromagnetic energy is applied to the dried droplets to prelithiate the active material and carbonize at least a portion of the polymer surrounding the active material. As a result, for example, when the active material is silicon, a carbon film 135 including a lithium-silicon alloy 140, a lithium-silicon oxide (lithium silicate 145), and pores 138 is obtained, as shown in FIG. 1.

[0056] The light electromagnetic energy used in the present invention is intense pulsed light (IPL) or microwaves.

[0057] Among the application of optical electromagnetic energy, IPL is performed by irradiating high-power xenon light. Meanwhile, the carbonization effect of the polymer can vary depending on the IPL application time. For example, when IPL is applied for 5 milliseconds or less, the carbonization effect is concentrated mainly on the outer shell, resulting in a shell structure with a hard, carbonized outer shell and a soft inner polymer shell. Alternatively, when IPL is applied for more than 5 milliseconds, the entire polymer is carbonized, resulting in a shell made entirely of carbon.

[0058] Upon application of light electromagnetic energy, the nanoporous shell formed by evaporation of the low boiling point polymer and solvent facilitates lithium diffusion, and the carbonized outer shell provides structural rigidity. If an inner shell of uncarbonized polymer is present, it can provide an elastic and deformable space for the volume change of the active material during the lithiation process.

[0059] The carbonized outer shell, or carbonized shell, provides electrical conductivity along the SEI (Solid Electrolyte Interphase) and structural support, while the soft polymer inner layer is elastic and provides space for the active material for volume expansion while preventing it from being crushed.

[0060] Depending on the power or time of microwave application, a shell may be formed that is only partially carbonized or entirely carbonized.

[0061] Meanwhile, after the application of light electromagnetic energy, the powdered anode material can be further pulverized by a known milling method such as ball milling or jet milling.

[0062] Prelithiation of an anode active material such as silicon by application of photoelectromagnetic energy is achieved by reaction of the active material with a lithium salt at high temperatures (e.g., above 200°C), resulting in the formation of Li x Si and / or Li x SiO y The lithiated active material particles are formed as follows.

[0063] In the method according to the present invention, a powdered active material is prelithiated by reducing lithium by a thermal reduction method, which involves applying a photoelectromagnetic energy treatment to a lithium salt. When a metal having a larger free energy change in the oxidation reaction than lithium is used, lithium is reduced and the metal is oxidized. For example, when Si metal, which is an anode material, is used as a reducing agent, application of photoelectromagnetic energy such as IPL reduces a lithium salt such as lithium oxide to lithium metal, resulting in a lithium-silicon alloy (Li x Si) and / or lithium silicate (Li x SiO y Prelithiated Si particles such as

[0064] FIG. 4 is a schematic diagram illustrating the application of IPL to a powdered encapsulated active material in an air suspension chamber.

[0065] IPL application is considered a more applicable energy application method for powdered encapsulated active materials because IPL can irradiate a large surface area at once. Also, typical IPL systems have pulse durations of a few milliseconds and energy densities of 12 J / cm. 2 When considering conventional IPL systems, the diffusion depth of the IPL radiation is limited to about 1 μm from the surface, which is more suitable for powdered active material treatment.

[0066] Referring to FIG. 4, a specially designed chamber 410 is used to uniformly irradiate the encapsulated active material powder 401 with intense pulsed light (IPL) 435 energy, and the dried encapsulated active material powder 401 is suspended in air using a blower 440. The chamber 410 is made of a light-transmitting material (such as glass or transparent polycarbonate). The blower 440 suspends the encapsulated active material 401 in air by continuous blowing. An IPL lamp 430 is positioned opposite the chamber 410 using a xenon lamp. The other side of the chamber 410 opposite the side where the IPL is irradiated is covered with a reflector 420 to irradiate all sides of the active material particles during the IPL irradiation process.

[0067] An anode material for a lithium secondary battery according to an embodiment of the present invention may be a powder including a lithiated active material and a shell layer surrounding the lithiated active material and having pores, as shown in Fig. 1. The lithiated active material includes a lithium-silicon alloy and a lithium silicate layer surrounding the lithium-silicon alloy. The shell layer may have an outermost layer made of carbon.

[0068] At least the outermost shell layer, which is made of carbon, may comprise 1D or 2D carbonaceous materials such as carbon nanotubes and / or graphene oxide, which improves the absorption of energy from electromagnetic waves over a wide wavelength range and improves the electrical conductivity of the resulting anode material.

[0069] The first charge process of a lithium secondary battery is crucial to its performance. During the first charge, the organic electrolyte may be reduced to form a solid electrolyte interface on the anode surface, or some lithium ions may be trapped by the electrode during the first lithiation process. This can lead to an irreversible loss of the battery's net energy capacity. The first cycle is particularly important when silicon is used as the anode, which undergoes significant volume changes during charge and discharge.

[0070] In the present invention, the loss of energy density in the first charging cycle can be compensated for by prelithiation of the active material using the method described above.

[0071] FIG. 5 is a diagram schematically illustrating the charge and discharge process of the anode material for a lithium secondary battery according to the present invention.

[0072] Silicon and silicon oxide anode active materials can be prelithiated to form a lithium-silicon alloy 510. A lithium silicate layer 520 may be formed on the surface of the lithium-silicon alloy 510. A carbon layer 530 containing numerous pores may be formed on the surface of the lithium silicate layer 520. Prelithiation of these anode active materials allows lithium elements to escape from the anode during discharge at the beginning of battery operation, forming silicon 550 and a silicon oxide layer 560 surrounding the silicon core, with a space 540 between these and the carbon layer. During charging, lithium elements are introduced into the anode. These charge and discharge processes can be facilitated by the numerous pores on the surface of the anode material. In the present invention, a hard carbon shell surrounds the active material to accommodate the expanded volume of the lithiated active material, i.e., to maintain the space 540 during discharge. This prevents the structure of the anode active material from being destroyed by the volume change of the silicon during subsequent charge and discharge processes.

[0073] FIG. 6 is a schematic diagram of an example of an apparatus for drying droplet-encapsulated active materials using the spray freeze drying technique.

[0074] The spray freeze drying system shown in FIG. 6 includes a transparent cylindrical chamber 610, an atomizing nozzle 620 for providing droplets of encapsulated active material 601, a nitrogen gas atomizer 630 with a nozzle 635 for freezing the encapsulated active material 601, and a vacuum unit 640 with a filter mesh and a vacuum pump for continuously drying the encapsulated active material within the transparent cylindrical chamber 610.

[0075] Using the apparatus shown in Figure 6, a liquid mixture is sprayed into a chamber to generate droplets, which are then flash-frozen using nitrogen gas to form frozen droplets, which can then be vacuum-dried into a powder.

[0076] The encapsulated active material powder freeze-dried according to FIG. 6 can then be carbonized by IPL or microwave irradiation in the air flotation device shown in FIG.

[0077] Although the present invention has been described above with reference to the preferred embodiment, various modifications and variations within the skill of ordinary artisans can be made therein. Therefore, these modifications and variations can be understood as being included within the scope of the present invention, provided that they do not deviate from the scope of the present invention.

Claims

1. mixing the active material, the polymer, and the lithium salt together in a solvent to form a liquid mixture; converting the liquid mixture into droplets and drying the droplets into a powder; applying light electromagnetic energy to the dried powder resultant to prelithiate the active material and carbonize at least a portion of the polymer; Including, A method for producing an anode material for a lithium secondary battery.

2. The active material contains at least one of silicon and silicon oxide. A method for producing the anode material for a lithium secondary battery according to claim 1.

3. The active material is surface-pretreated by applying light electromagnetic energy. A method for producing the anode material for a lithium secondary battery according to claim 1.

4. The application of the photo-electromagnetic energy causes the lithium salt and the active material to react with each other, and the gas product of the reaction escapes to the outside, forming pores. A method for producing the anode material for a lithium secondary battery according to claim 1.

5. The lithium salt is Li ２ O, LiOH, LiO ２ C.H., Li ２ CO ３ , Li ２ C ２ O ４ , Li ３ C ６ H ５ O ７ , LiNO ３ , LiCl, LiF, or a lithium-functionalized polymer; A method for producing the anode material for a lithium secondary battery according to claim 1.

6. The solvent includes an aqueous or organic solvent. A method for producing the anode material for a lithium secondary battery according to claim 1.

7. converting the liquid mixture into droplets and drying the droplets to a powder, spraying the liquid mixture into an air flotation chamber to generate droplets; drying the droplets while circulating them within the air flotation chamber using a heater; Including, A method for producing the anode material for a lithium secondary battery according to claim 1.

8. applying optical electromagnetic energy includes applying optical electromagnetic energy within the air suspension chamber. A method for producing the anode material for a lithium secondary battery according to claim 7.

9. converting the liquid mixture into droplets and drying the droplets to a powder, spraying the liquid mixture into a chamber to generate droplets; flash-freezing the droplets in the chamber using nitrogen gas to form frozen droplets; Vacuum drying the frozen droplets to form powder; Including, A method for producing the anode material for a lithium secondary battery according to claim 1.

10. a lithiated active material; a shell layer surrounding the lithiated active material and having pores; Including, the lithiated active material comprises a lithium-silicon alloy and a lithium silicate layer surrounding the lithium-silicon alloy; The outermost shell layer is formed of carbon. Anode material for lithium secondary batteries.

11. The shell layer is formed entirely of carbon. The anode material for a lithium secondary battery according to claim 10.

12. The shell layer includes an outer shell formed of carbon and an inner shell formed of a polymer. The anode material for a lithium secondary battery according to claim 10.

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