High-entropy nanofibers, manufacturing methods thereof, and anode materials for lithium ion batteries comprising the same

Abstract

The high-entropy nanofiber of the present invention is a nanofiber comprising five or more base elements selected from the group consisting of Ni, Co, Fe, Mg, Cu, Cr, Mn, Mo, V, Nb, Ta, Ti, Zr, W, Si, Hf, and Al, and is characterized by having a hollow interior. The method for manufacturing high-entropy nanofibers according to the present invention may include the steps of: preparing a first solution by mixing an organic material having a first calcination temperature and a solvent; preparing a second solution by mixing an organic material having a second calcination temperature and a metal precursor; performing coaxial electrospinning using the first solution and the second solution; and performing heat treatment. The negative electrode material for a lithium-ion battery according to the present invention comprises high-entropy nanofibers.

Description

Technology Field

[0001] The present invention relates to high-entropy nanofibers, a method for manufacturing the same, and a negative electrode material for a lithium-ion battery containing the same. Background Technology

[0002] With the rapid increase in energy demand, lithium-ion batteries are attracting attention as next-generation energy storage devices and vehicle energy sources.

[0003] Currently, the lithium-ion battery market has commercialized systems consisting of four major components: cathode materials based on ternary transition metal oxides containing lithium, such as Ni-Co-Mn (NCM) or Ni-Co-Al (NCA), graphite-based anode materials, lithium carbonate-based liquid electrolytes, and polymer-based separators. However, with the growth of the electric vehicle market, there are limitations in securing a driving range greater than that of internal combustion engine vehicles with the energy density of existing lithium-ion battery systems, so efforts are required to develop lithium-ion battery systems with higher energy density.

[0004] The theoretical capacity of graphite, a commercial anode material for lithium-ion batteries, has reached a capacity limit of 375 mAh / g and is showing limitations in applications requiring high energy density.

[0005] Silicon anode materials, which have recently garnered significant attention, are characterized by a high theoretical capacity of 4,200 mAh / g. Research is currently underway to improve their properties by replacing graphite or adding silicon to existing graphite to enhance energy density. However, silicon has the disadvantage of causing significant stress on the electrode structure during charging and discharging, leading to short circuits from the electrode's current collector and the excessive formation of SEI layers, which degrade the battery's rate capability and lifespan. Therefore, gradually increasing the amount of silicon in existing graphite materials is a more realistic alternative than using pure silicon.

[0006] Recently, SiO₂ has been used as a negative electrode material for lithium-ion secondary batteries. xAlthough much research is being conducted on metal oxides (MOs) such as SnO2 and Ti4O7, there are many limitations due to volume expansion, electrical conductivity, and structural stability issues. Therefore, to overcome these disadvantages, research is underway on metal oxides with binary and ternary systems by doping or partially substituting various metal ions.

[0007] High-entropy metal oxides (HEMOs) are oxides containing five or more metals that provide numerous reaction sites and ion transport channels, offering enhanced lithium-ion storage and transport capabilities and excellent cycling stability. Additionally, HEMOs exhibit high electrical conductivity and excellent structural stability, which can effectively mitigate capacity degradation and structural damage issues associated with cathode materials.

[0008] However, there are several challenges that need to be addressed to actually implement HEMOs in lithium-ion secondary batteries. First is the composition and structural design of the metallic materials. HEMOs containing five or more types of metal ions are difficult to obtain as uniform and phase-pure materials due to their complex characteristics. Therefore, synthesis parameters must be precisely controlled. Furthermore, it is necessary to understand the relationships between the composition, morphology, structure, and electrochemical properties of HEMOs and to optimize their performance. The problem to be solved

[0009] The objective of the present invention is to provide a high-entropy nanofiber of a novel structure, a method for manufacturing the same, and a negative electrode material for a lithium-ion battery comprising the same. means of solving the problem

[0010] In order to achieve the objectives of the present invention as described above,

[0011] The high-entropy nanofiber of the present invention is a nanofiber comprising five or more base elements selected from the group consisting of Ni, Co, Fe, Mg, Cu, Cr, Mn, Mo, V, Nb, Ta, Ti, Zr, W, Si, Hf, and Al, and is characterized by having a hollow interior.

[0012] The method for manufacturing high-entropy nanofibers according to the present invention may include the steps of: preparing a first solution by mixing an organic material having a first calcination temperature and a solvent; preparing a second solution by mixing an organic material having a second calcination temperature and a metal precursor; performing coaxial electrospinning using the first solution and the second solution; and performing heat treatment.

[0013] The negative electrode material for a lithium-ion battery according to the present invention comprises high-entropy nanofibers. Effects of the invention

[0014] High-entropy nanofibers are novel structures not previously reported that possess a stable structure, a large specific surface area, and excellent electrical conductivity, making them suitable for use in various fields such as secondary batteries, biomaterials, catalysts, and sensors. Preferably, they can be used as a negative electrode material for lithium-ion batteries.

[0015] The internal voids and porous shape of the nanofibers of the present invention can improve structural stability and allow for numerous electrochemical reaction sites. Specifically, due to the internal voids and pores of the nanofibers, Li + Structural stability can be increased by effectively accommodating volume changes during ion insertion / extraction. In addition, internal voids and a porous structure allow the liquid electrolyte to efficiently penetrate into the structure, thereby Li + It can shorten the diffusion path of ions.

[0016] Meanwhile, HEMO possesses thermodynamic stability and excellent metallic conductivity, making it advantageous for the cycling stability and electron transport of lithium-ion batteries. Additionally, it can provide abundant active sites.

[0017] Therefore, when the high-entropy nanofiber of the present invention is used as a negative electrode material for a lithium-ion battery, excellent lithium-ion storage characteristics and high-rate characteristics can be achieved. Brief explanation of the drawing

[0018] FIG. 1 is a schematic diagram illustrating a method for manufacturing fibers according to one embodiment of the present invention. Figure 2(a) is an FE-SEM image of Comparative Example 1, (b) is an FE-SEM image of Comparative Example 2, and (c) is an FE-SEM image of Example 1. Figures 3 (a) to (c) are the elemental mapping images and EDX analysis results of Example 1 (HF-HEMO). FIGS. 4(a) to 4(c) are charge / discharge curves, where (a) is the charge / discharge curve of Comparative Example 1, (b) is the charge / discharge curve of Comparative Example 2, and (c) is the charge / discharge curve of Example 1. FIG. 4(d) shows current densities from 0.1 to 5.0 A g -1 The rate performance of Comparative Examples 1 and 2 and Example 1 when increased stepwise is shown. FIG. 4(e) is 2 A g -1 This is the result of measuring the cycling performance at a constant high current density. Specific details for implementing the invention

[0019] Hereinafter, various embodiments of this document are described with reference to the accompanying drawings. The embodiments and the terms used therein are not intended to limit the technology described in this document to specific embodiments and should be understood to include various modifications, equivalents, and / or substitutions of said embodiments.

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0022] High-entropy nanofibers according to various embodiments of the present invention are nanofibers comprising five or more base elements selected from the group consisting of Ni, Co, Fe, Mg, Cu, Cr, Mn, Mo, V, Nb, Ta, Ti, Zr, W, Si, Hf, and Al, and are characterized by having a hollow interior.

[0023] Specifically, the nanofiber may include Ni, Co, Fe, Mg, and Cu. In this case, Ni, Co, Fe, Mg, and Cu may be high-entropy metal oxides (HEMO) having a single crystal phase. That is, the nanofiber may include a high-entropy metal oxide with a cubic crystal phase containing Ni, Co, Fe, Mg, and Cu. In this case, Ni may be included in 3 to 7 at%, Co in 3 to 7 at%, Fe in 3 to 6 at%, Mg in 4 to 14 at%, Cu in 5 to 9 at%, and the remainder as oxygen (O).

[0024] The nanofibers can have a diameter of 300 nm to 500 nm. Through this diameter range, when the nanofibers of the present invention are applied as a negative electrode material for a lithium-ion battery, an excellent capacity retention rate can be secured.

[0025] Nanofibers can be porous. In this case, the BET (Brunauer-Emmett-Teller) surface area of ​​the nanofiber is 14 m² 2 g -1 to 33 m 2 g -1 It could be.

[0026] The nanofiber is characterized by being manufactured by coaxial electrospinning. Through this, the nanofiber of the present invention can have a hollow shape with an empty interior.

[0027] The aforementioned high-entropy nanofiber is a novel structure not previously reported, possessing a stable structure, a large specific surface area, and excellent electrical conductivity, making it suitable for use in various fields such as secondary batteries, biomaterials, catalysts, and sensors. Preferably, it can be used as a negative electrode material for lithium-ion batteries.

[0028] The internal voids and porous shape of the nanofibers of the present invention can improve structural stability and allow for numerous electrochemical reaction sites. Specifically, due to the internal voids and pores of the nanofibers, Li + Structural stability can be increased by effectively accommodating volume changes during ion insertion / extraction. In addition, internal voids and a porous structure allow the liquid electrolyte to efficiently penetrate into the structure, thereby Li + It can shorten the diffusion path of ions.

[0029] Meanwhile, HEMO possesses thermodynamic stability and excellent metallic conductivity, making it advantageous for the cycling stability and electron transport of lithium-ion batteries. Additionally, it can provide abundant active sites.

[0030] Therefore, when the high-entropy nanofiber of the present invention is used as a negative electrode material for a lithium-ion battery, excellent lithium-ion storage characteristics can be achieved.

[0032] Hereinafter, a method for manufacturing high-entropy nanofibers according to various embodiments of the present invention will be described.

[0033] A method for manufacturing high-entropy nanofibers according to various embodiments of the present invention may include the steps of: preparing a first solution by mixing an organic material having a first calcination temperature and a solvent; preparing a second solution by mixing an organic material having a second calcination temperature and a metal precursor; performing coaxial electrospinning using the first solution and the second solution; and performing heat treatment.

[0034] First, in the step of preparing the first solution, an organic material having a first calcination temperature and a solvent can be mixed and prepared.

[0035] The organic material having the first calcination temperature may include at least one selected from the group consisting of polyethylene glycol, PVP (Polyvinylpyrrolidone), PAN (Polyacrylonitrile), PAA (polyacrylic acid), PVA (polyvinyl alcohol), PMMA (polymethyl methacrylate), PVDF (polyvinylidene fluoride), PVac (polyvinylacetate), PS (polystyrene), PVC (polyvinyl chloride), PEI (polyetherimide), PBI (polybenzimidasol), PEO (polyethylene oxide), PCL (poly-e-caprolactone), PA-6 (polyamide-6), PTT (polytrimethylenetetraphthalate), PDLA (poly D,L-lactic acid), polycarbonate, polydioxanone, polyglycolide, and dextran. Preferably, the organic material having the first calcination temperature may be PMMA. PMMA has a small molecular weight and can be well dispersed in a solvent.

[0036] The solvent can be, for example, dimethylformamide (DMF).

[0037] The weight ratio of the organic material having the first calcination temperature and the solvent may be 1:5 to 1:9. Preferably, the weight ratio of the organic material having the first calcination temperature and the solvent may be 1:7. Through this weight ratio, the shape of the nanofiber produced when the first solution is subsequently electrospun can be well maintained without damage.

[0038] In the step of preparing the second solution, a second solution can be prepared by mixing an organic material and a metal precursor having a second calcination temperature.

[0039] The organic material having the second calcination temperature may include at least one selected from the group consisting of polyethylene glycol, PVP (Polyvinylpyrrolidone), PEDOT (Polyethylenedioxythiophene), PAN (Polyacrylonitrile), PAA (polyacrylic acid), PVA (polyvinyl alcohol), PMMA (polymethyl methacrylate), PVDF (polyvinylidene fluoride), PVac (polyvinylacetate), PS (polystyrene), PVC (polyvinyl chloride), PEI (polyetherimide), PBI (polybenzimidasol), PEO (polyethylene oxide), PCL (poly e-caprolactone), PA-6 (polyamide-6), PTT (polytrimethylenetetraphthalate), PDLA (poly D,L-lactic acid), polycarbonate, polydioxanone, polyglycolide, and dextran. The organic material having the second calcination temperature may include at least two types of organic materials. For example, organic materials having a second calcination temperature may include PMMA and PAN. This allows for securing a second calcination temperature higher than the first calcination temperature.

[0040] Meanwhile, the organic material having the second calcination temperature includes PAN and PMMA, and the weight ratio may be 10:3 to 10:5. Meanwhile, the examples are not limited thereto, and the mixing weight ratio may vary depending on the porosity and thickness of the nanofiber to be obtained.

[0041] The metal precursor may include five or more metal salts selected from the group consisting of Ni, Co, Fe, Mg, Cu, Cr, Mn, Mo, V, Nb, Ta, Ti, Zr, W, Si, Hf, and Al. Preferably, the metal precursor may include Ni, Co, Fe, Mg, and Cu metal salts. For example, the metal precursor may include Co(NO3)2^6H2O, Cu(NO3)2^3H2O, Fe(NO3)3^9H2O, Mg(NO3)2^6H2O, and Ni(NO3)2^6H2O. In this case, the mixing ratio of metal ions may be Ni : Co : Fe : Mg : Cu = 1 : 1 : 1 : 1 : 1 in molar ratio. Through this, excellent cycle characteristics, rate characteristics, and high reversible capacity can be secured when the manufactured nanofiber is applied as a negative electrode material for a lithium-ion battery. Meanwhile, the crystal structure and physical properties can be controlled depending on the mixing time of the metal precursor and the concentration of metal ions.

[0042] Next, in the electrospinning step, coaxial electrospinning can be performed using the previously prepared first solution and second solution.

[0043] Specifically, referring to FIG. 1, a first solution can be extruded from the inside of the nozzle and a second solution can be extruded from the outside of the nozzle. Meanwhile, in the case of an organic material having a first calcination temperature contained in the first solution, the calcination temperature is lower than that of an organic material having a second calcination temperature contained in the second solution. That is, since the first calcination temperature is lower than the second calcination temperature, the material in the first solution extruded from the inside of the nozzle can shrink during electrospinning, thereby inducing a hollow shape inside.

[0044] At this time, electrospinning is performed with an applied voltage of 13 kV to 23 kV and a flow rate of 1 mL h -1 to 5 mL h -1It can be performed under conditions of a distance of Tip to drum collector of 13 cm to 23 cm and a drum speed of 100 rpm to 200 rpm. Under these conditions, the diameter of the nanofiber produced can be manufactured to be 300 nm to 500 nm. Meanwhile, the examples are not limited thereto, and the diameter, outer wall porosity, and thickness of the nanofiber can be controlled in various ways through various electrospinning conditions.

[0045] Next, the electrospun fibers can be dried at 50 to 70 ℃ and then heat-treated. The heat-treatment step can be performed at 400 ℃ to 600 ℃ at a heating rate of 3 ℃ / min to 10 ℃ / min.

[0047] The present invention will be explained in detail below through examples. However, the following examples are merely illustrative of the present invention and do not limit the present invention.

[0049] Example 1: Preparation of porous hollow-HEMO nanofibers

[0050] To fabricate porous hollow-HEMO nanofibers, a coaxial nozzle as shown in Fig. 1 (17G-23G, 17G: Ø in =1.07 mm, Ø out =1.47 mm, 23G: Ø in =0.33 mm, Ø out =0.63 mm) was used. For electrospinning, the solutions were prepared as follows: a first solution extruded from the inside (In) of the nozzle to form an internal pore, i.e., a tube shape, and a second solution from the outside (Out) containing external HEMO.

[0051] The first solution was prepared by mixing PMMA in DMF solvent at a weight ratio of 1:7. The second solution was prepared by dispersing 10 mmol of Co(NO3)2·6H2O, Cu(NO3)2·3H2O, Fe(NO3)3·9H2O, Mg(NO3)2·6H2O, and Ni(NO3)2·6H2O in a polymer solution containing PAN and PMMA for 12 hours. At this time, the weight ratio of PAN to PMMA in the polymer solution was mixed at 10:4. In addition, the molar ratio of metal ions was set to Ni : Co : Fe : Mg : Cu = 1 : 1 : 1 : 1 : 1.

[0052] The previously prepared first and second solutions were loaded into a nozzle and electrospinning was performed. The electrospinning conditions are as follows.

[0053] - Applied voltage: 18 kV

[0054] - Flow rate: 3 mL h -1

[0055] - Distance of Tip to drum collector: 18 cm

[0056] - Drum speed: 150 rpm

[0057] The electrospun material was dried at 60°C for 2 hours, and then heat-treated in a 500°C kiln for 2 hours in an air atmosphere. During this process, the heating rate was 5°C min -1 It was.

[0058] The heat-treated nanofibers were ground and used as the final negative electrode material for lithium-ion secondary batteries.

[0060] Example 2: Lithium secondary battery manufacturing

[0061] A slurry was prepared by using the porous hollow-HEMO nanofiber prepared in Example 1 as the negative electrode active material and dispersing a conductive agent (Super P carbon black) and a binder (Polyacrylic acid) in distilled water in a weight ratio of 70:20:10.

[0062] The slurry was mixed using a slurry mixer and applied to the copper foil current collector using the braiding technique. Afterward, it was dried for one hour in an air atmosphere at 80°C and compressed to 80% of the original coating thickness.

[0063] The compressed electrode was cut into a disc with a diameter of 1.564 cm and vacuum dried at 110°C for 24 hours.

[0064] Subsequently, a CR2032 type half-cell was fabricated using a lithium metal cut to a diameter of 16 mm as the positive electrode in a high-purity argon glove box (<0.01 ppm of oxygen and moisture level).

[0065] The electrolyte used was 1 M LiPF6 / EC-DMC (3:7 vol.%) containing 10 wt.% fluorinated ethylene carbonate, and the separator was a polypropylene membrane (Celgard 2400).

[0066] The completed battery was subjected to charge and discharge tests under a rate capability of 0.1 C.

[0068] Comparative Examples 1 and 2: Preparation of NiO fibers and solid porous HEMO fibers

[0069] NiO fibers were prepared as Comparative Example 1, and non-hollow, solid porous HEMO fibers were prepared as Comparative Example 2. The synthesis methods of Comparative Examples 1 and 2 were similar to those of Example 1, except that a single nozzle (Ø) was used instead of a coaxial nozzle (17G-23G). in =0.33 mm, Ø out=0.63 mm) was used. In addition, the second solution for the preparation of Comparative Example 1 was prepared in the same manner as Example 1, except that only Ni(NO3)2*?*6H2O was added. The second solution for the preparation of Comparative Example 2 was prepared in the same manner as Example 1, and the first solution was not used compared to Example 1. Subsequently, synthesis was performed by spinning under the same spinning conditions as Example 1.

[0071] Experimental Example 1 - Observation of the morphology of the manufactured fiber

[0072] The morphology of the fibers prepared according to Example 1, Comparative Example 1, and Comparative Example 2 was observed. FIG. 2(a) is an FE-SEM image of Comparative Example 1, FIG. 2(b) is an FE-SEM image of Comparative Example 2, and FIG. 2(c) is an FE-SEM image of Example 1. Referring to FIG. 2(a) and (b), the NiO fiber of Comparative Example 1 and the HEMO fiber of Comparative Example 2 exhibited a uniform porous fiber structure with a diameter of approximately 250 nm. Meanwhile, referring to FIG. 2(c), it can be confirmed that the porous hollow-HEMO fiber according to Example 1 exhibited a hollow structure with a diameter of approximately 400 nm.

[0074] Experimental Example 2 - Analysis of Chemical Characteristics of Fibers Prepared According to the Example

[0075] Chemical properties of the fiber prepared according to Example 1 were observed through three rounds of EDX analysis. Figures 3 (a) to (c) show the elemental mapping images and EDX analysis results of Example 1 (HF-HEMO).

[0076] Referring to Figures 3 (a) to (c), it can be seen that Ni, Co, Fe, Mg, Cu, and O components are uniformly distributed throughout the nanofiber. Additionally, it was confirmed that Ni is 3 to 7 at%, Co is 3 to 7 at%, Fe is 3 to 6 at%, Mg is 4 to 14 at%, Cu is 5 to 9 at%, and the remainder is oxygen (O).

[0078] Experimental Example 2 - Analysis of Electrochemical Properties of the Manufactured Fiber

[0079] The effect of the morphological characteristics of the fibers prepared according to Example 1 (HF-HEMO), Comparative Example 1 (F-NiO), and Comparative Example 2 (F-HEMO) on the electrochemical performance as a LIB cathode was analyzed.

[0080] FIGS. 4(a) to 4(c) are charge / discharge curves, where (a) is the charge / discharge curve of Comparative Example 1, (b) is the charge / discharge curve of Comparative Example 2, and (c) is the charge / discharge curve of Example 1. Specifically, FIGS. 4(a), (b), and (c) are 1.0 Ag -1 The 1st and 50th charge / discharge curves of each fiber at the current density are shown. Referring to Fig. 4(c), it can be seen that the 1st and 50th charge / discharge curves are nearly identical compared to Figs. 4(a) and (b). In other words, it can be confirmed that the porous hollow-HEMO fiber of Example 1 exhibits excellent redox reversibility and cycle stability. Through this, it can be seen that the hollow fiber structure facilitates ion diffusion and electron transport characteristics during charging and discharging.

[0081] Fig. 4(d) shows current densities from 0.1 to 5.0 Ag -1 The rate performance of Comparative Examples 1 and 2 and Example 1 when increased stepwise is shown. In the case of the porous hollow-HEMO fiber of Example 1, the current density is 5.0 A g -1 Despite increasing to 610 mAh g -1 It showed a high capacity. In addition, the current density was 0.1 A g -1 It was found that the capacity recovered well after returning to the state, and that Example 1 maintained a very stable state even after cycling at high current density.

[0082] Fig. 4(e) is 2 A g -1 This is the result of measuring the cycling performance at a constant high current density.

[0083] Referring to Fig. 4(e), the NiO fiber of Comparative Example 1 exhibited very rapid capacity fading during cycling and showed poor cycling characteristics. On the other hand, for the hollow-HEMO fiber of Example 1, 2 A g -1 Excellent long-term cycle characteristics were confirmed by showing a capacity retention rate of approximately 100% for 300 cycles even at high current densities.

[0084] Through the above results, the superior electrochemical performance of HEMO compared to single metal oxide NiO was verified, and it was confirmed that HEMO with a hollow structure exhibited superior capacity compared to non-hollow HEMO. In other words, the examples were confirmed to possess excellent cycle characteristics, rate characteristics, and high reversible capacity.

[0086] The present invention has been described above with reference to its preferred embodiments. Those skilled in the art will understand that the present invention may be embodied in modified forms without departing from the essential characteristics of the invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the invention is defined by the claims, not by the foregoing description, and all variations within the scope of the claims should be interpreted as being included in the invention.

Claims

Claim 1 Nanofibers comprising Ni, Co, Fe, Mg, and Cu having a single crystal phase, wherein the interior of the nanofiber is hollow and the BET (Brunauer-Emmett-Teller) surface area is 14 m² 2 g -1 to 33 m 2 g -1 High-entropy nanofibers characterized by being high-entropy. Claim 2 delete Claim 3 delete Claim 4 The high-entropy nanofiber according to claim 1, characterized in that the nanofiber has a diameter of 300 nm to 500 nm. Claim 5 A high-entropy nanofiber according to claim 1, characterized in that the nanofiber comprises 3 to 7 at% Ni, 3 to 7 at% Co, 3 to 6 at% Fe, 4 to 14 at% Mg and 5 to 9 at% Cu. Claim 6 A high-entropy nanofiber according to claim 1, characterized in that the nanofiber is manufactured by coaxial electrospinning. Claim 7 The method comprises the steps of: preparing a first solution by mixing an organic material having a first calcination temperature and a solvent; preparing a second solution by mixing an organic material having a second calcination temperature and a metal precursor; performing coaxial electrospinning using the first solution and the second solution; and performing a heat treatment, wherein the metal precursor is a metal salt of Ni, Co, Fe, Mg, and Cu, the first calcination temperature is lower than the second calcination temperature, and the heat treatment step is performed at 400 ℃ to 600 ℃ at a heating rate of 3 ℃ / min to 10 ℃ / min, so as to be hollow with an internal structure and a BET (Brunauer-Emmett-Teller) surface area of ​​14 m² 2 g -1 to 33 m 2 g -1 A method for manufacturing high-entropy nanofibers characterized by manufacturing high-entropy nanofibers. Claim 8 delete Claim 9 A method for manufacturing high-entropy nanofibers according to claim 7, wherein the organic material having the first calcination temperature and the organic material having the second calcination temperature comprise at least one selected from the group consisting of polyethylene glycol, PVP (Polyvinylpyrrolidone), PEDOT (Polyethylenedioxythiophene), PAN (Polyacrylonitrile), PAA (polyacrylic acid), PVA (polyvinyl alcohol), PMMA (polymethyl methacrylate), PVDF (polyvinylidene fluoride), PVac (polyvinylacetate), PS (polystyrene), PVC (polyvinyl chloride), PEI (polyetherimide), PBI (polybenzimidasol), PEO (polyethylene oxide), PCL (poly e-caprolactone), PA-6 (polyamide-6), PTT (polytrimethylenetetraphthalate), PDLA (poly D,L-lactic acid), polycarbonate, polydioxanone, polyglycolide, and dextran. Claim 10 In claim 7, the method for manufacturing high-entropy nanofibers comprises at least two types of organic materials having the second calcination temperature. Claim 11 A method for manufacturing high-entropy nanofibers according to claim 7, characterized in that the weight ratio of the organic material having the first calcination temperature and the solvent is 1:5 to 1:

9. Claim 12 delete Claim 13 A method for manufacturing high-entropy nanofibers according to claim 7, wherein in the electrospinning step, the first solution is spun from inside the nozzle and the second solution is spun from outside the nozzle. Claim 14 delete Claim 15 A negative electrode material for a lithium-ion battery comprising a high-entropy nanofiber according to any one of claims 1, 4 to 6.

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