Coating composition for coating surface of secondary battery electrode active material, secondary battery electrode material, and method for manufacturing same comprising same

Abstract

The present invention relates to a coating composition comprising MXene and pitch for coating the surface of a secondary battery electrode active material, a secondary battery electrode material, and a method for manufacturing same comprising same.

Description

Coating composition for surface coating of secondary battery electrode active material, secondary battery electrode material and manufacturing method thereof including the same

[0001] The present invention relates to a coating composition for surface coating of a secondary battery electrode active material including MXene and pitch, a secondary battery electrode material, and a manufacturing method thereof including the same.

[0002]

[0003] Due to the rapid increase in fossil fuel use, the demand for alternative or clean energy is increasing, and as part of this, the most actively researched field is power generation and storage using electrochemical reactions.

[0004] Secondary batteries are a prime example of electrochemical devices that utilize this electrochemical energy, and their applications are expanding. With the recent technological development and increasing demand for portable devices such as laptops, mobile phones, and cameras, the demand for secondary batteries as an energy source has rapidly increased. Among these secondary batteries, lithium secondary batteries, which boast high energy density and high capacity, have been extensively studied and are now commercialized and widely used.

[0005] In general, secondary batteries are composed of a positive electrode, a negative electrode, an electrolyte, and a separator. The positive electrode material that constitutes the positive electrode of a lithium secondary battery is a metal oxide such as LiCoO2, Li(NiCoMn)O2, Li(NiCoAl)O2, LiFePO4, LiMnO2, LiMn2O4, or LiCrO2, and the negative electrode material that constitutes the negative electrode is a carbon-based material such as metal lithium, graphite, or activated carbon, or silicon oxide (SiO x) are being used. Among the above negative electrode materials, metallic lithium was mainly used in the early days, but as the charge and discharge cycle progresses, lithium atoms grow on the surface of metallic lithium, damaging the separator and destroying the battery. Therefore, carbon-based materials are mainly used recently. However, carbon-based materials have a low theoretical capacity of only about 400 mAh / g, so various studies are being conducted to replace the carbon-based materials using high-capacity materials such as silicon (Si) with a high theoretical capacity (4,200 mAh / g) as negative electrode materials.

[0006] Meanwhile, when using anode materials such as silicon, a technology is being applied to coat the surface of the anode material with pitch, which acts as a conductive material and binder, to prevent changes in volume, etc. However, to ensure high electrical conductivity, the pitch undergoes a carbonization process at a temperature of approximately 1,300℃ when coated on the anode material. However, the temperature generated during this carbonization process causes the silicon used as the anode material to clump, which has the problem of reducing the performance of the secondary battery.

[0007]

[0008] The present invention has been devised to overcome the above-described problems, and provides a coating composition for surface coating of a secondary battery electrode active material, a secondary battery electrode material, and a manufacturing method thereof including the same, which can secure a certain level of electrical conductivity and prevent silicon agglomeration during the carbonization process even when the carbonization process is performed at a temperature lower than 1,300°C (approximately, 600 to 1,000°C) by including MXene and pitch, thereby improving the performance of a secondary battery to which the same is applied.

[0009]

[0010] In order to solve the above-described problem, the coating composition for surface coating of the secondary battery electrode active material of the present invention may include a carbonized coating powder.

[0011] As a preferred embodiment of the present invention, the coating powder may include MXene and pitch represented by the following chemical formula 1.

[0012] [Chemical Formula 1]

[0013] M n+1 X n T x

[0014] In the above chemical formula 1, M is selected from one of the transition metals, X is selected from C or N, T is selected from one of O, F, OH, CO2, and Cl, and n is a rational number satisfying 1 to 4.

[0015] As a preferred embodiment of the present invention, the MXene represented by the chemical formula 1 is Ti3C2T x It could be Maxine.

[0016] As a preferred embodiment of the present invention, the MXene represented by the chemical formula 1 is Ti3C2T having hydrophobic properties. x It could be Maxine.

[0017] As a preferred embodiment of the present invention, the pitch may include at least one selected from petroleum pitch, coal tar pitch, and mesogenic pitch.

[0018] As a preferred embodiment of the present invention, the maxine and pitch represented by the chemical formula 1 may be included in a weight ratio of 1:4 to 55.

[0019] As a preferred embodiment of the present invention, the secondary battery may be a lead (Pd) battery, a nickel-cadmium (NiCd) battery, a nickel-metal (Ni-Metal) hydrogen battery, a lithium ion (Li-ion) battery, or a lithium ion polymer (Li-ion polymer) battery.

[0020] As a preferred embodiment of the present invention, the electrode active material may be a negative electrode active material.

[0021] As a preferred embodiment of the present invention, the negative active material may include silicon (Si).

[0022] As a preferred embodiment of the present invention, the carbonized coating powder may be carbonized at a temperature of 300 to 1,000°C for 30 to 180 minutes.

[0023] Meanwhile, the method for manufacturing a coating composition for surface coating of a secondary battery electrode active material of the present invention may include a first step of manufacturing a coating solution by adding and mixing MXene and pitch, represented by the following chemical formula 1, into a solvent, a second step of vacuum-drying the coating solution to manufacture a coating powder from which the solvent has been removed, and a third step of carbonizing the coating powder to manufacture a coating composition for surface coating of a secondary battery electrode active material.

[0024] [Chemical Formula 1]

[0025] M n+1 X n T x

[0026] In the above chemical formula 1, M is selected from one of the transition metals, X is selected from C or N, T is selected from one of O, F, OH, CO2, and Cl, and n is a rational number satisfying 1 to 4.

[0027] As a preferred embodiment of the present invention, the solvent may include at least one selected from among methylpyrrolidone (N-Methyl-2-pyrrolidone), tetrahydrofuran, hexane, toluene, and ethanol.

[0028] As a preferred embodiment of the present invention, vacuum drying can be performed at a temperature of 50 to 130°C for 3 to 12 hours.

[0029] As a preferred embodiment of the present invention, carbonization can be performed at a temperature of 300 to 1,000°C for 30 to 180 minutes.

[0030] Furthermore, the secondary battery electrode material of the present invention may include an electrode active material and a coating layer coated on the surface of the electrode active material.

[0031] As a preferred embodiment of the present invention, the coating layer may include a carbonized coating powder.

[0032] As a preferred embodiment of the present invention, the coating powder may include MXene and pitch represented by the following chemical formula 1.

[0033] [Chemical Formula 1]

[0034] M n+1 X n T x

[0035] In the above chemical formula 1, M is selected from one of the transition metals, X is selected from C or N, T is selected from one of O, F, OH, CO2, and Cl, and n is a rational number satisfying 1 to 4.

[0036] As a preferred embodiment of the present invention, the maxine and pitch represented by the chemical formula 1 may be included in a weight ratio of 1:4 to 55.

[0037] As a preferred embodiment of the present invention, the electrode material may be a cathode material.

[0038] As a preferred embodiment of the present invention, the electrode active material may be a spherical graphite powder having silicon coated on the surface.

[0039] As a preferred embodiment of the present invention, the spherical graphite powder having silicon coated on the surface may have an average particle size of 10 to 200 μm.

[0040] As a preferred embodiment of the present invention, the spherical graphite powder having silicon coated on the surface may contain 5 to 15 wt% of silicon.

[0041] Meanwhile, the method for manufacturing a secondary battery electrode material of the present invention may include a first step of preparing a MXene solution, a pitch solution, and an electrode active material solution, respectively; a second step of preparing a mixed solution by mixing the MXene solution, the pitch solution, and the negative electrode active material solution; and a third step of manufacturing a secondary battery electrode material by carbonizing the electrode active material having the MXene and pitch coated on the surface thereof.

[0042] [Chemical Formula 1]

[0043] M n+1 X n T x

[0044] In the above chemical formula 1, M is selected from one of the transition metals, X is selected from C or N, T is selected from one of O, F, OH, CO2, and Cl, and n is a rational number satisfying 1 to 4.

[0045] As a preferred embodiment of the present invention, the maxine and pitch represented by the chemical formula 1 may have a weight ratio of 1:4 to 55.

[0046]

[0047] The coating composition for surface coating of a secondary battery electrode active material of the present invention, the secondary battery electrode material and the manufacturing method thereof including the same include MXene and pitch, thereby ensuring a certain level of electrical conductivity and preventing silicon agglomeration during the carbonization process even when the carbonization process is performed at a temperature lower than 1,300°C (approximately, 600 to 1,000°C), thereby improving the performance of a secondary battery to which the same is applied.

[0048]

[0049] Figure 1 is a graph showing the charge / discharge rates of each of the secondary battery coin cells manufactured in Manufacturing Example 2 and Comparative Manufacturing Examples 2 to 3.

[0050]

[0051] Hereinafter, the present invention will be described in more detail.

[0052] When using existing anode materials such as silicon, technology is being applied to coat the surface of the anode material with pitch, which acts as a conductive material and binder, to prevent changes in volume, etc. However, to ensure high electrical conductivity, the pitch undergoes a carbonization process at a temperature of approximately 1,300℃ when coated on the anode material. However, the temperature generated during this carbonization process causes the silicon used as the anode material to clump, which has the problem of reducing the performance of the secondary battery.

[0053] Accordingly, the present invention includes MXene and pitch, thereby ensuring a certain level of electrical conductivity and preventing silicon agglomeration during the carbonization process even when the carbonization process is performed at a temperature lower than 1,300°C (approximately 600 to 1,000°C), thereby improving the performance of a secondary battery to which it is applied.

[0054]

[0055] The coating composition for surface coating of the secondary battery electrode active material of the present invention may include a carbonized coating powder.

[0056] At this time, the coating powder may include MXene and pitch.

[0057] MXene, first discovered in 2011, is a two-dimensional planar ceramic material composed of atomic-thick layers of carbon or nitrogen bonded to a transition metal. Furthermore, MXene possesses metallic properties (conductivity) due to the transition metal, while also exhibiting hydrophilicity due to the presence of hydroxyl groups or oxygen at the terminals.

[0058] Specifically, the maxine of the present invention may be a maxine represented by the following chemical formula 1.

[0059] [Chemical Formula 1]

[0060] M n+1 X n T x

[0061] In the above chemical formula 1, M is selected from one of the transition metals, X is selected from C or N, T is selected from one of O, F, OH, CO2, and Cl, and n is a rational number satisfying 1 to 4.

[0062] More specifically, the MXene represented by the above chemical formula 1 is Ti3C2T x It may be a MXene. That is, it is a nanomaterial composed of a dual element of a heavy metal atom such as titanium (Ti) and a carbon (C) atom, and it may be a 2D nanomaterial having a two-dimensional plate-like structure with a thickness of at least 1 nm (nanometer) and a length of 100 nm to several μm (micrometers). In addition, preferably, the MXene represented by the chemical formula 1 is Ti3C2T having hydrophobic properties. x It could be Maxine, and more preferably C 16 H 33 NH3-Ti3C2T x It could be Maxine. C 16 H 33 NH3-Ti3C2T x Maxine is Ti3C2T surface-treated with alkylammonium.x Maxine. Through this surface treatment, Ti3C2T x Maxine can have hydrophobic properties.

[0063] Pitch is a solid organic material at room temperature, or a residue from the thermal decomposition of tar distillation. It consists of a complex mixture of numerous aromatic hydrocarbons and heterocyclic compounds. Pitch does not have a constant melting point, but rather a wide softening range, with a softening temperature ranging from approximately 320 K to 570 K, depending on molecular weight and composition.

[0064] The pitch of the present invention may include at least one selected from petroleum pitch, coal tar pitch, and mesogenic pitch, and preferably may include petroleum pitch.

[0065]

[0066] Meanwhile, the coating composition for surface coating of the secondary battery electrode active material of the present invention may contain the MXene and pitch represented by the above chemical formula 1 in a weight ratio of 1:4 to 55, preferably 1:6 to 24, more preferably 1:8 to 19, and most preferably 1:8 to 10. If the weight ratio is less than 1:4, there may be a problem of reduced performance due to a decrease in ionic conductivity and / or an increase in resistance due to an overloading problem of MXene, and if it exceeds 1:55, there may be a problem of weakening the connection between MXenes, thereby weakening the electrical conductivity and / or ionic conductivity, or increasing the instability of the secondary battery electrode material.

[0067] In addition, the secondary battery of the present invention may be a lead (Pd) battery, a nickel-cadmium (NiCd) battery, a nickel-metal (Ni-Metal) hydrogen battery, a lithium ion (Li-ion) battery, or a lithium ion polymer (Li-ion polymer) battery, and preferably a lithium ion (Li-ion) battery.

[0068] Additionally, the electrode active material of the present invention may be a negative electrode active material, and the negative electrode active material may include silicon (Si).

[0069] In addition, the carbonized coating powder can be formed at a temperature of 300 to 1,000°C, preferably 700 to 1,000°C, more preferably 750 to 900°C, and even more preferably 800 to 850°C for 30 to 180 minutes, preferably 40 to 130 minutes, and even more preferably 100 to 130 minutes. If the carbonization temperature is less than 300°C, the carbonization of the pitch may be incomplete, resulting in almost no electrical conductivity, or there may be a problem in which the coating is easily peeled off due to a change in the volume of silicon contained in the negative electrode active material. If it exceeds 1,000°C, there may be problems such as a change in shape and / or agglomeration due to melting of silicon contained in the negative electrode active material, and hardening of the negative electrode active material.

[0070]

[0071] Meanwhile, the method for manufacturing a coating composition for surface coating of a secondary battery electrode active material of the present invention includes steps 1 to 3.

[0072] First, in the first step of the method for manufacturing a coating composition for surface coating of a secondary battery electrode active material of the present invention, a coating solution can be manufactured by adding and mixing MXene and pitch into a solvent.

[0073] At this time, the maxine and pitch are as described above, and the solvent may include at least one selected from among methylpyrrolidone (N-Methyl-2-pyrrolidone), tetrahydrofuran, hexane, toluene, and ethanol.

[0074] Additionally, maxine and pitch can be mixed in a weight ratio of 1:4 to 55, preferably 1:6 to 24, more preferably 1:8 to 19, and most preferably 1:8 to 10.

[0075] Next, in the second step of the method for manufacturing a coating composition for surface coating of a secondary battery electrode active material of the present invention, the coating solution manufactured in the first step can be vacuum-dried to manufacture a coating powder from which the solvent has been removed.

[0076] At this time, vacuum drying can be performed at a temperature of 50 to 130°C, preferably 110 to 125°C, for 3 to 12 hours, preferably 9 to 11 hours. If the vacuum drying temperature is lower than 50°C, reliable solvent recovery may be difficult, quality issues due to uneven drying speed, physical and / or chemical stability, etc. may occur, and if it exceeds 120°C, cracks may occur due to stress and / or distortion caused by the rapid drying speed.

[0077] Finally, in the third step of the method for manufacturing a coating composition for surface coating of a secondary battery electrode active material of the present invention, the coating composition for surface coating of a secondary battery electrode active material can be manufactured by carbonizing the coating powder manufactured in the second step.

[0078] At this time, carbonization can be performed at a temperature of 300 to 1,000°C, preferably at a temperature of 700 to 1,000°C, more preferably at a temperature of 750 to 900°C, and even more preferably at a temperature of 800 to 850°C for 30 to 180 minutes, preferably at a temperature of 40 to 130 minutes, and even more preferably at a temperature of 100 to 130 minutes. If the carbonization temperature is less than 300°C, the carbonization of the pitch may be incomplete, resulting in almost no electrical conductivity, or there may be a problem in which the coating is easily peeled off due to a change in the volume of silicon included in the negative electrode active material, and if it exceeds 1,000°C, there may be problems such as a change in shape and / or agglomeration due to melting of silicon included in the negative electrode active material, and hardening of the negative electrode active material.

[0079]

[0080] Furthermore, the secondary battery electrode material of the present invention may include an electrode active material and a coating layer coated on the surface of the electrode active material. In this case, the electrode material may be a negative electrode material, and the electrode active material may be a spherical graphite powder having a silicon coating on its surface.

[0081] In addition, the spherical graphite powder coated with silicon on the surface has an average particle size of 10 to 200 μm, preferably 30 to 100 μm, and may contain 5 to 15 wt% of silicon.

[0082] Additionally, the coating layer may include a carbonized coating powder, and the coating powder may include MXene and pitch. In this case, MXene and pitch are each as described above.

[0083] Specifically, maxine and pitch may be included in a weight ratio of 1:4 to 55, preferably 1:6 to 24, more preferably 1:8 to 19, and most preferably 1:8 to 10.

[0084]

[0085] Meanwhile, the method for manufacturing a secondary battery electrode material of the present invention includes steps 1 to 3.

[0086] First, in the first step of the secondary battery electrode material manufacturing method of the present invention, a MXene solution, a pitch solution, and an electrode active material solution may be prepared, respectively. Specifically, the MXene solution may include the MXene and the solvent described above, the pitch solution may include the pitch and the solvent described above, and the electrode active material solution may include the electrode active material and the solvent described above. At this time, each solvent may include at least one selected from methylpyrrolidone (N-Methyl-2-pyrrolidone), tetrahydrofuran, hexane, toluene, and ethanol.

[0087] Next, in the second step of the method for manufacturing a secondary battery electrode material of the present invention, the MXene solution, the pitch solution, and the negative electrode active material solution prepared in the first step are mixed to prepare a mixed solution, and the solvent included in the prepared mixed solution is removed, thereby manufacturing an electrode active material having MXene and pitch coated on the surface. At this time, the MXene, pitch, and electrode active material are as described above. In addition, the solvent can be removed using a rotary evaporator. Specifically, the MXene and pitch can have a weight ratio of 1:4 to 55, preferably a weight ratio of 1:6 to 24, more preferably a weight ratio of 1:8 to 19, and most preferably a weight ratio of 1:8 to 10.

[0088] Finally, in the third step of the method for manufacturing a secondary battery electrode material of the present invention, a secondary battery electrode material can be manufactured by carbonizing an electrode active material having a surface coated with maxine and pitch manufactured in the second step. At this time, carbonization can be performed at a temperature of 300 to 1,000°C, preferably at a temperature of 700 to 1,000°C, more preferably at a temperature of 750 to 900°C, and even more preferably at a temperature of 800 to 850°C for 30 to 180 minutes, preferably at a temperature of 40 to 130 minutes, and even more preferably at a temperature of 100 to 130 minutes. If the carbonization temperature is less than 300°C, the carbonization of the pitch may be incomplete, resulting in almost no electrical conductivity, or there may be a problem in which the coating is easily peeled off due to a change in the volume of silicon included in the negative electrode active material, and if it exceeds 1,000°C, there may be problems such as a change in shape and / or agglomeration due to melting of silicon included in the negative electrode active material, and hardening of the negative electrode active material.

[0089]

[0090] Hereinafter, the present invention will be described in more detail through examples, but the following examples do not limit the scope of the present invention, and should be interpreted as helping to understand the present invention.

[0091]

[0092] Example 1: Preparation of a coating composition for surface coating of a secondary battery electrode active material

[0093] (1) A coating solution was prepared by adding and mixing 0.2 g of MXene and 1.8 g of pitch to 6 mL of solvent. At this time, methylpyrrolidone (N-Methyl-2-pyrrolidone) was used as the solvent, and C was used as the MXene. 16 H 33 NH3-Ti3C2T x Maxine was used, and petroleum pitch was used as the pitch. In addition, maxine and pitch were added and mixed in a solvent at a weight ratio of 1:9.

[0094] (2) The prepared coating solution was vacuum-dried at a temperature of 120°C for 10 hours to remove the solvent, thereby preparing a coating powder.

[0095] (3) The manufactured coating powder was carbonized at a temperature of 800°C for 120 minutes to manufacture a coating composition for surface coating of a secondary battery electrode active material.

[0096]

[0097] Example 2: Preparation of a coating composition for surface coating of a secondary battery electrode active material

[0098] A coating composition for surface coating of a secondary battery electrode active material was prepared in the same manner as in Example 1. However, unlike Example 1, carbonization was performed at a temperature of 700°C for 120 minutes.

[0099]

[0100] Example 3: Preparation of a coating composition for surface coating of a secondary battery electrode active material

[0101] (1) A coating solution was prepared by adding and mixing 0.04 g of MXene and 1.96 g of pitch to 6 mL of solvent. At this time, methylpyrrolidone (N-Methyl-2-pyrrolidone) was used as the solvent, and C was used as the MXene. 16 H 33 NH3-Ti3C2T x Maxine was used, and petroleum pitch was used as the pitch. In addition, maxine and pitch were added and mixed in a solvent at a weight ratio of 1:49.

[0102] (2) The prepared coating solution was vacuum-dried at a temperature of 120°C for 10 hours to remove the solvent, thereby preparing a coating powder.

[0103] (3) The manufactured coating powder was carbonized at a temperature of 800°C for 120 minutes to manufacture a coating composition for surface coating of a secondary battery electrode active material.

[0104]

[0105] Example 4: Preparation of a coating composition for surface coating of a secondary battery electrode active material

[0106] A coating composition for surface coating of a secondary battery electrode active material was prepared in the same manner as in Example 3. However, unlike Example 3, carbonization was performed at a temperature of 700°C for 120 minutes.

[0107]

[0108] Example 5: Preparation of a coating composition for surface coating of a secondary battery electrode active material

[0109] A coating composition for surface coating of a secondary battery electrode active material was prepared in the same manner as in Example 3. However, unlike Example 3, carbonization was performed at a temperature of 900°C for 120 minutes.

[0110]

[0111] Comparative Example 1: Preparation of a coating composition for surface coating of a secondary battery electrode active material.

[0112] (1) A coating solution was prepared by adding and mixing 2 g of pitch to 6 mL of solvent. At this time, methylpyrrolidone (N-Methyl-2-pyrrolidone) was used as the solvent, and petroleum pitch was used as the pitch.

[0113] (2) The prepared coating solution was vacuum-dried at a temperature of 120°C for 10 hours to remove the solvent, thereby preparing a coating powder.

[0114] (3) The manufactured coating powder was carbonized at a temperature of 800°C for 120 minutes to manufacture a coating composition for surface coating of a secondary battery electrode active material.

[0115]

[0116] Comparative Example 2: Preparation of a coating composition for surface coating of a secondary battery electrode active material.

[0117] A coating composition for surface coating of a secondary battery electrode active material was prepared using the same method as in Comparative Example 1. However, unlike Comparative Example 1, carbonization was performed at a temperature of 700°C for 120 minutes.

[0118]

[0119] Experimental Example 1: Electrical Conductivity and Resistance Measurement

[0120] Using a powder resistance meter (powder resistance pressure: 2,000 kgf, 0.4 - 0.5 g standard), the electrical conductivity and resistance of each coating composition for surface coating of secondary battery electrode active materials manufactured in Examples 1 to 5 and Comparative Examples 1 to 2 were measured, and the results are shown in Table 1 below.

[0121]

[0122] Experimental Example 2: Density Measurement

[0123] Using a density analyzer, the density of each coating composition for surface coating of secondary battery electrode active materials manufactured in Examples 1 to 5 and Comparative Examples 1 to 2 was measured and shown in Table 1 below.

[0124]

[0125] As can be seen in Table 1, the coating composition for surface coating of the secondary battery electrode active material manufactured in Example 1 was confirmed to have an electrical conductivity increase of approximately 60% compared to the coating composition for surface coating of the secondary battery electrode active material manufactured in Comparative Example 1.

[0126] In addition, it was confirmed that the coating composition for surface coating of the secondary battery electrode active material manufactured in Example 1 had increased electrical conductivity compared to the coating composition for surface coating of the secondary battery electrode active material manufactured in Example 3.

[0127] In addition, it was confirmed that the coating composition for surface coating of the secondary battery electrode active material manufactured in Example 2 and Comparative Example 2 had no electrical conductivity and thus could not be measured.

[0128] In addition, it was confirmed that the coating composition for surface coating of the secondary battery electrode active material manufactured in Example 4 had significantly lower electrical conductivity compared to the coating composition for surface coating of the secondary battery electrode active material manufactured in Example 1.

[0129] In addition, it was confirmed that the coating composition for surface coating of the secondary battery electrode active material manufactured in Example 5 had a significantly lower electrical conductivity compared to the coating composition for surface coating of the secondary battery electrode active material manufactured in Example 1.

[0130]

[0131] Manufacturing Example 1: Manufacturing of secondary battery negative electrode material

[0132] (1) 20 mg of MXene was added and dispersed in 10 mL of THF (Tetrahydrofuran) solvent to prepare a MXene solution. At this time, C as MXene 16 H 33 NH3-Ti3C2T x Maxine was used. In addition, a pitch solution was prepared by adding and dispersing 180 mg of pitch in 20 mL of THF solvent. Petroleum pitch was used as the pitch. In addition, a negative electrode active material solution was prepared by adding and dispersing 1,800 mg of negative electrode active material in 90 mL of THF solvent. In this case, spherical graphite powder (average particle size: 75 μm, containing 10 wt% silicon) coated with silicon (Si) on the surface was used as the negative electrode active material.

[0133] (2) The prepared Maxene solution, pitch solution, and negative electrode active material solution were mixed for 30 minutes to prepare a mixed solution, and the THF solvent contained in the mixed solution was removed using a rotary evaporator, thereby preparing a negative electrode active material having Maxene and pitch coated on the surface.

[0134] (3) A secondary battery negative electrode material was manufactured by carbonizing a negative electrode active material having a surface coated with maxine and pitch at a temperature of 800°C for 120 minutes.

[0135]

[0136] Comparative Manufacturing Example 1: Manufacturing of Secondary Battery Negative Electrode Material

[0137] (1) A pitch solution was prepared by adding and dispersing 200 mg of pitch into 20 mL of THF solvent. Petroleum pitch was used as the pitch. In addition, a negative electrode active material solution was prepared by adding and dispersing 1,800 mg of negative electrode active material into 90 mL of THF solvent. At this time, spherical graphite powder (average particle size: 75 μm, containing 10 wt% silicon) coated on the surface was used as the negative electrode active material.

[0138] (2) The prepared pitch solution and negative electrode active material solution were mixed for 30 minutes to prepare a mixed solution, and the THF solvent contained in the mixed solution was removed using a rotary evaporator to prepare a negative electrode active material having a pitch coating on the surface.

[0139] (3) A secondary battery negative electrode material was manufactured by carbonizing the negative electrode active material having a pitch coating on the manufactured surface at a temperature of 800°C for 120 minutes.

[0140]

[0141] Manufacturing Example 2: Manufacturing of secondary battery coin cells

[0142] (1) A negative electrode slurry was prepared by mixing 570 mg of the secondary battery negative electrode material prepared in Manufacturing Example 1, 1,000 mg of CMC (Carboxy methyl cellulose) solution (solid content: 1.5 wt%), and 30 mg of SBR (styrene-butadiene rubber) solution (solid content: 50 wt%).

[0143] (2) A copper (Cu) sheet was prepared as a negative electrode collector, and the prepared negative electrode material slurry was uniformly coated on one side of the negative electrode collector to a thickness of 210 μm using a doctor blade device to form a sheet, and then vacuum-dried at a temperature of 80℃ for 10 hours and punched to a diameter of 13.5 mm to manufacture a secondary battery coin cell. In addition, an electrolyte was filled in the manufactured secondary battery coin cell, and a 1.0 M LiPF6 solution containing 5 wt% FEC (Fluoroethylene carbonate) was used as the electrolyte. In addition, the 1.0 M LiPF6 solution was a solvent in which EC (Ethylene Carbonate) and EMC (Ethyl methyl carbonate) were mixed in a 3:7 volume% ratio.

[0144]

[0145] Comparative Manufacturing Example 2: Manufacturing of Secondary Battery Coin Cells

[0146] (1) A negative electrode slurry was prepared by mixing 570 mg of the secondary battery negative electrode material manufactured in Comparative Manufacturing Example 1, 1,000 mg of CMC (Carboxy methyl Cellulose) solution (solid content: 1.5 wt%), and 30 mg of SBR (styrene-butadiene rubber) solution (solid content: 50 wt%).

[0147] (2) A copper (Cu) sheet was prepared as a negative electrode collector, and the prepared negative electrode material slurry was uniformly coated on one side of the negative electrode collector to a thickness of 210 μm using a doctor blade device to form a sheet, and then vacuum-dried at a temperature of 80℃ for 10 hours and punched to a diameter of 13.5 mm to manufacture a secondary battery coin cell. In addition, an electrolyte was filled in the manufactured secondary battery coin cell, and a 1.0 M LiPF6 solution containing 5 wt% FEC (Fluoroethylene carbonate) was used as the electrolyte. In addition, the 1.0 M LiPF6 solution was a solvent in which EC (Ethylene Carbonate) and EMC (Ethyl methyl carbonate) were mixed in a 3:7 volume% ratio.

[0148]

[0149] Comparative Manufacturing Example 3: Manufacturing of Secondary Battery Coin Cells

[0150] (1) A negative electrode slurry was prepared by mixing 570 mg of a negative electrode active material, 1,000 mg of a CMC (Carboxy methyl cellulose) solution (solid content: 1.5 wt%), and 30 mg of a SBR (styrene-butadiene rubber) solution (solid content: 50 wt%). At this time, spherical graphite powder (average particle size: 75 μm, containing 10 wt% silicon) coated with silicon (Si) on the surface was used as the negative electrode active material.

[0151] (2) A copper (Cu) sheet was prepared as a negative electrode collector, and the prepared negative electrode material slurry was uniformly coated on one side of the negative electrode collector to a thickness of 210 μm using a doctor blade device to form a sheet, and then vacuum-dried at a temperature of 80℃ for 10 hours and punched to a diameter of 13.5 mm to manufacture a secondary battery coin cell. In addition, an electrolyte was filled in the manufactured secondary battery coin cell, and a 1.0 M LiPF6 solution containing 5 wt% FEC (Fluoroethylene carbonate) was used as the electrolyte. In addition, the 1.0 M LiPF6 solution was a solvent in which EC (Ethylene Carbonate) and EMC (Ethyl methyl carbonate) were mixed in a 3:7 volume% ratio.

[0152]

[0153] Experimental Example 3: Measurement of Current Rate

[0154] Using a charger / discharger (WBCS3000, Wonatech), the constant current charge / discharge rate (Current Rate) of each of the secondary battery coin cells manufactured in Manufacturing Example 2 and Comparative Manufacturing Examples 2 and 3 was measured at a temperature of 25°C and a voltage range of 0.01 to 1.5 V, and the measurement graph is shown in Fig. 1 (= (c) Si / C-pitch-MXene shown in Fig. 1 represents the secondary battery coin cell manufactured in Manufacturing Example 2, (b) Si / C-pitch represents the secondary battery coin cell manufactured in Comparative Manufacturing Example 2, and (a) Si / C bare represents the secondary battery coin cell manufactured in Comparative Manufacturing Example 3.).

[0155] As can be seen in Fig. 1, it was confirmed that the secondary battery coin cell manufactured in Manufacturing Example 2 had a higher charge / discharge capacity than the secondary battery coin cells manufactured in Comparative Manufacturing Examples 2 to 3.

[0156]

[0157] The above illustrates and describes specific embodiments. However, the invention is not limited to the aforementioned embodiments, and those skilled in the art will readily appreciate that various modifications and implementations can be made without departing from the spirit and scope of the invention as set forth in the claims below.

Claims

1. Contains carbonized coating powder; The above coating powder is a coating composition for surface coating of a secondary battery electrode active material, comprising MXene and pitch represented by the following chemical formula 1. [Chemical Formula 1] M n+1 X n T x In the above chemical formula 1, M is selected from one of the transition metals, X is selected from C or N, T is selected from one of O, F, OH, CO2, and Cl, and n is a rational number satisfying 1 to 4.

2. In paragraph 1, The MXene represented by the above chemical formula 1 is Ti3C2T x Maxine, a coating composition for surface coating of a secondary battery electrode active material.

3. In paragraph 1, The MXene represented by the above chemical formula 1 is Ti3C2T which has hydrophobic properties. x Maxine, a coating composition for surface coating of a secondary battery electrode active material.

4. In paragraph 1, A coating composition for surface coating of a secondary battery electrode active material, wherein the pitch comprises at least one selected from among petroleum pitch, coal tar pitch, and mesogenic pitch.

5. In paragraph 1, A coating composition for surface coating of a secondary battery electrode active material, comprising maxine and pitch represented by the above chemical formula 1 in a weight ratio of 1:4 to 55.

6. In paragraph 1, A coating composition for surface coating of a secondary battery electrode active material, wherein the secondary battery is a lead (Pd) battery, a nickel-cadmium (NiCd) battery, a nickel-metal (Ni-metal) hydrogen battery, a lithium ion (Li-ion) battery or a lithium ion polymer (Li-ion polymer) battery.

7. In paragraph 1, The above electrode active material is a coating composition for surface coating of a secondary battery electrode active material, which is a negative electrode active material.

8. In paragraph 7, The above negative active material is a coating composition for surface coating of a secondary battery electrode active material, which contains silicon (Si).

9. In paragraph 1, A coating composition for surface coating of a secondary battery electrode active material, wherein the above carbonized coating powder is carbonized at a temperature of 300 to 1,000°C for 30 to 180 minutes.

10. A first step of preparing a coating solution by adding and mixing MXene and pitch represented by the following chemical formula 1 into a solvent; A second step of manufacturing a coating powder from which the solvent has been removed by vacuum drying the coating solution; and A third step of producing a coating composition for surface coating of a secondary battery electrode active material by carbonizing the above coating powder; A method for manufacturing a coating composition for surface coating of a secondary battery electrode active material, comprising: [Chemical Formula 1] M n+1 X n T x In the above chemical formula 1, M is selected from one of the transition metals, X is selected from C or N, T is selected from one of O, F, OH, CO2, and Cl, and n is a rational number satisfying 1 to 4.

11. In paragraph 10, A method for manufacturing a coating composition for surface coating of a secondary battery electrode active material, wherein the solvent comprises at least one selected from among methylpyrrolidone (N-Methyl-2-pyrrolidone), tetrahydrofuran, hexane, toluene, and ethanol.

12. In paragraph 10, A method for manufacturing a coating composition for surface coating of a secondary battery electrode active material, wherein the above vacuum drying is performed at a temperature of 50 to 130°C for 3 to 12 hours.

13. In paragraph 10, A method for manufacturing a coating composition for surface coating of a secondary battery electrode active material, wherein the above carbonization is performed at a temperature of 300 to 1,000°C for 30 to 180 minutes.

14. Electrode active material; and A coating layer coated on the surface of the electrode active material; The above coating layer comprises a carbonized coating powder; The above coating powder is a secondary battery electrode material comprising MXene and pitch represented by the following chemical formula 1. [Chemical Formula 1] M n+1 X n T x In the above chemical formula 1, M is selected from one of the transition metals, X is selected from C or N, T is selected from one of O, F, OH, CO2, and Cl, and n is a rational number satisfying 1 to 4.

15. In paragraph 14, A secondary battery electrode material comprising the maxine and pitch represented by the above chemical formula 1 in a weight ratio of 1:4 to 55.

16. In paragraph 14, The above electrode material is a negative electrode material, a secondary battery electrode material.

17. In paragraph 14, The above electrode active material is a secondary battery electrode material that is a spherical graphite powder with silicon coated on the surface.

18. In paragraph 17, A secondary battery electrode material, wherein the spherical graphite powder coated with silicon on the surface has an average particle size of 10 to 200 μm and contains 5 to 15 wt% of silicon.

19. Step 1: Preparing a Maxine solution, a Peach solution, and an electrode active material solution, respectively; A second step of preparing a mixed solution by mixing the above-mentioned Maxene solution, pitch solution, and negative electrode active material solution, and removing the solvent contained in the mixed solution to prepare an electrode active material having Maxene and pitch represented by the following chemical formula 1 coated on the surface; and A third step of manufacturing a secondary battery electrode material by carbonizing an electrode active material coated with maxine and pitch on the surface; A method for manufacturing a secondary battery electrode material, comprising: [Chemical Formula 1] M n+1 X n T x In the above chemical formula 1, M is selected from one of the transition metals, X is selected from C or N, T is selected from one of O, F, OH, CO2, and Cl, and n is a rational number satisfying 1 to 4.

20. In paragraph 19, A method for manufacturing a secondary battery electrode material, wherein the maxine and pitch represented by the above chemical formula 1 have a weight ratio of 1:4 to 55.

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