KR102518691B1 - An electrode active material, an anode including the same, a second battery including the same, the fabrication method of the electrode active material - Google Patents

Abstract

The negative active material and the secondary battery include a core containing lead, and a shell surrounding the core and containing carbon. A secondary battery including an anode active material can achieve long life and high efficiency.

Description

A negative electrode active material, a negative electrode including the same, a secondary battery including the same, and a method for manufacturing a negative electrode active material

The present invention relates to a negative active material, a negative electrode including the same, a secondary battery including the same, and a method for manufacturing the negative active material, and more particularly, a negative electrode active material capable of promoting long life and high efficiency of a secondary battery, a negative electrode including the same, It relates to a secondary battery including the same, and a method for manufacturing an anode active material.

A lead-acid battery, which is a typical secondary battery, has a structure in which lead is used as a negative electrode and lead having lead oxide on the surface is used as a positive electrode, and the positive electrode is immersed in dilute sulfuric acid. When a lead-acid battery is discharged, lead (Pb) on the surface of the anode reacts with sulfate ions to become lead sulfate (PbSO ₄ ) and emits electrons. After receiving the emitted electrons, lead oxide (PbO ₂ ) on the surface of the anode reacts with sulfuric acid and becomes lead sulfate. Through this reaction, current flows in the lead-acid battery. When charging a lead-acid battery, the reverse reaction occurs when discharging. Therefore, the secondary battery has the advantage of being able to be used for a long period of time by repeating charging and discharging.

However, lead sulfate is precipitated as particles in the active material at the cathode and anode during discharge of the conventional lead-acid battery, and due to its low solubility, it easily grows into a crystalline state and gradually loses activity and becomes unusable. As the cycle progresses, this becomes a factor that deteriorates the performance during partial charging, and in particular, lead sulfate formed on the negative electrode has a major effect.

As an alternative to lead-acid batteries, EDLCs (electrical double layer capacitors) with excellent charge-discharge cycles are being developed, but low energy density and high prices are becoming problems.

Pb/C batteries containing lead and carbon are also to overcome the disadvantages of lead-acid batteries, and carbon active materials (P60 powder, carbon powder such as carbon black) are used together with binders (CMC (Carboxymethyl Cellulose), PTFE (Polytetrafluoroethylene Emulsion), etc.) A secondary battery system that is used by applying it on a lead-based grid or lead plate. It uses 2 positive PbO2 sheets and 1 negative electrode sheet, and uses a separator (PE, AGM separator) to prevent a short circuit between the positive and negative electrodes. It has a structure in which it is used and adhered with a PVC (Polyvinyl Chloride) plate so that the distance between the electrodes does not increase. In general, sulfuric acid is used as the electrolyte in Pb/C batteries, and the anode is a lead dioxide electrode like the anode of a lead acid battery, and the cathode is a capacitor electrode using activated carbon. The electrode reaction occurring at both electrodes is as follows.

[anode]

1/2PbO ₂ (s) + 1/2H ₂ SO ₄ (aq) + H ⁺ (aq) + e ^- ↔ 1/2PbSO ₄ (s) + H ₂ O (l)

[cathode]

(CS ^- // H ⁺ ) → CS ^- // H ⁺ + e ^-

[full reaction]

1/2PbO ₂ (s) + 1/2H ₂ SO ₄ (aq) + H ⁺ (aq) + e ^- → 1/2PbSO ₄ (s) + H ₂ O (l)

CS ^- is a carbon atom on the electrode surface, "//" means a double layer of charge stored in each layer, and the electrode composed of activated carbon with a high surface area (1500 m / g) is due to acid on the electrode surface layer. Protons, which are hydrogen cations, accumulate. That is, during charging and discharging, electric charges move through a faradic process in the battery-type lead dioxide electrode and proceed through oxidation and reduction reactions, and in the carbon electrode operated as a capacitor, charges are accumulated or discharged in a non-paradic process in the double layer. .

However, the Pb/C battery also has a problem in that the gap between the electrodes is widened due to hydrogen gas generated by an electrochemical reaction (oxidation/reduction reaction) that occurs during cell operation, similar to conventional lead acid batteries. In addition, there are still problems due to the volume change of the negative electrode active material, such as a pulsation phenomenon caused by the generated PbSO ₄ .

Korean Registered Patent No. 828,879

An object of the present invention is to provide a negative electrode active material capable of promoting long life and high efficiency of a secondary battery.

An object of the present invention is to provide a negative electrode capable of achieving long life and high efficiency of a secondary battery.

An object of the present invention is to provide a long-life, high-efficiency secondary battery.

An object of the present invention is to provide a method for manufacturing an anode active material capable of providing a long-life, high-efficiency secondary battery.

An anode active material according to an embodiment of the present invention includes a core containing lead, and a shell surrounding the core and containing carbon.

The lead and the carbon may be connected by a covalent bond.

The core may not contain lead oxide.

An anode according to an embodiment of the present invention includes an anode active material and a conductive material containing carbon. The negative electrode active material includes a lead-containing core, and a shell surrounding the core and containing carbon.

A secondary battery according to an embodiment of the present invention includes a positive electrode including lead, an electrolyte provided on the positive electrode, and a negative electrode provided on the electrolyte. The anode includes an anode active material. The negative electrode active material includes a core containing lead, and a shell surrounding the core and containing carbon.

The negative electrode may further include a conductive material containing carbon.

A method for preparing an anode active material according to an embodiment of the present invention includes dissolving a lead precursor in distilled water to form a first solution, dissolving a catalyst in distilled water to form a second solution, and dispersing a carbon active material in a solvent to form a first solution. Forming a first dispersion solution, providing the first solution and the second solution to the first dispersion solution to form a mixed solution, sonication of the mixed solution, and the ultrasonic treatment drying the mixed solution to prepare an anode active material including a core containing lead and a shell surrounding the core and containing carbon.

In the step of forming the first solution, the lead precursor is PbNO ₃ , (CH ₃ SO ₃ ) ₂ Pb, PbCl ₂ , Pb(OAc) ₂ , Pb(NO ₃ ) ₂ , Pb(acac) ₂ , and PbCO includes at least one of _{the three}

In the step of forming the second solution, the catalyst includes at least one of NaBH ₄ , NaH, trimethyl borate, and trisodium citrate.

In the step of forming the first dispersion solution, the carbon active material includes at least one of graphite and activated carbon.

In the step of forming the first dispersion solution, the solvent includes at least one of ethanol and isopropyl alcohol.

The ultrasonic treatment includes a first ultrasonic treatment of the mixed solution, and a second ultrasonic treatment of the mixed solution subjected to the first ultrasonic treatment.

The first ultrasonic treatment may be performed for 40 to 60 minutes, and the second ultrasonic treatment may be performed for 20 to 40 minutes.

The manufacturing method of an anode active material according to an embodiment of the present invention may further include washing the mixed solution subjected to ultrasonic treatment with at least one of distilled water and ethanol.

The step of preparing the negative active material may be performed by drying at 40 to 60°C for 22 to 26 hours.

According to the negative active material according to an embodiment of the present invention, long life and high efficiency of a secondary battery can be promoted.

According to the negative electrode according to an embodiment of the present invention, long life and high efficiency of the secondary battery can be achieved.

A secondary battery according to an embodiment of the present invention can promote long life and high efficiency.

According to the manufacturing method of an anode active material according to an embodiment of the present invention, it is possible to provide a cathode active material capable of promoting long life and high efficiency of a secondary battery.

1 is a schematic cross-sectional view of a secondary battery according to an embodiment of the present invention.
2 is a schematic cross-sectional view of an anode according to an embodiment of the present invention.
3 is a schematic cross-sectional view of an anode active material according to an embodiment of the present invention.
4 is a schematic flow chart sequentially illustrating a method for manufacturing an anode active material according to an embodiment of the present invention.
5 is a transmission electron microscope analysis photograph of the negative electrode active material of Example 1.
6 is a graph showing the results of EDAX analysis of the negative active material of Example 1.
7 (a) is a BET graph of normal carbon, and (b) is a BET graph of the anode active material of Example 1.
8a and 8b are graphs of XRD analysis of the anode active material of Example 1;
9A and 9B are graphs of XPS analysis of the anode active material of Example 1.
10 is a graph showing resistance values of the negative electrode active material of Example 1 measured.
11 (a) shows a graph of discharge by C-rate, and (b) is a graph showing voltage by capacity per volume of negative electrode active material.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete and the spirit of the present invention will be sufficiently conveyed to those skilled in the art.

Like reference numerals have been used for like elements throughout the description of each figure. In the accompanying drawings, the dimensions of the structures are shown enlarged than actual for clarity of the present invention. Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof. In addition, when a part such as a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where another part is present in the middle. Conversely, when a part such as a layer, film, region, plate, etc. is said to be "under" another part, this includes not only the case where it is "directly below" the other part, but also the case where another part is in the middle.

Unless otherwise specified, all numbers, values and/or expressions expressing quantities of components, reaction conditions, polymer compositions and formulations used herein refer to the number of factors that such numbers arise, among other things, to obtain such values. Since these are approximations that reflect the various uncertainties of the measurement, they should be understood to be qualified by the term "about" in all cases. Also, when numerical ranges are disclosed herein, such ranges are contiguous and include all values from the minimum value of such range to the maximum value inclusive, unless otherwise indicated. Furthermore, where such ranges refer to integers, all integers from the minimum value to the maximum value inclusive are included unless otherwise indicated.

In this specification, where ranges are stated for a variable, it will be understood that the variable includes all values within the stated range inclusive of the stated endpoints of the range. For example, a range of "5 to 10" includes values of 5, 6, 7, 8, 9, and 10, as well as any subrange of 6 to 10, 7 to 10, 6 to 9, 7 to 9, and the like. inclusive, as well as any value between integers that fall within the scope of the stated range, such as 5.5, 6.5, 7.5, 5.5 to 8.5 and 6.5 to 9, and the like. Also, for example, the range of "10% to 30%" includes values such as 10%, 11%, 12%, 13%, etc., and all integers up to and including 30%, as well as values from 10% to 15%, 12% to 12%, etc. It will be understood to include any sub-range, such as 18%, 20% to 30%, and the like, as well as any value between reasonable integers within the scope of the stated range, such as 10.5%, 15.5%, 25.5%, and the like.

Hereinafter, an anode active material, an anode, and a secondary battery according to an embodiment of the present invention will be described.

1 is a schematic cross-sectional view of a secondary battery according to an embodiment of the present invention. 2 is a schematic cross-sectional view of an anode according to an embodiment of the present invention. 3 is a schematic cross-sectional view of an anode active material according to an embodiment of the present invention.

1 to 3 , a secondary battery 10 according to an embodiment of the present invention includes a positive electrode 100, an electrolyte 200, and a negative electrode 300. Anode 100 includes lead. Electrolyte 200 is provided on the anode 100 . The positive electrode 100 and the negative electrode 300 are spaced apart from each other by the electrolyte 200 . Electrolyte 200 may be sulfuric acid having a concentration of 35 to 45% by weight. Although not shown, the secondary battery 10 according to an embodiment of the present invention may further include a separator.

The negative electrode 300 includes the negative electrode active material 310 . The negative electrode 300 may further include a conductive material 320 . The conductive material 320 may include carbon. The conductive material 320 may improve conductivity of the negative electrode 300 . The conductive material 320 is not particularly limited as long as it is commonly used, but may be, for example, at least one of graphite and carbon K.

Although not shown, the negative electrode 300 may include a negative electrode plate. The negative plate contains lead. The negative electrode plate may be, for example, a flat plate shape. The negative active material 310 may be provided on the negative electrode plate. The conductive material 320 may be provided on the negative electrode plate.

The negative electrode 300 according to an embodiment of the present invention may be formed, for example, by providing a conductive paste on a negative electrode plate. The conductive paste includes an anode active material 310 and a binder. The conductive paste may further include a conductive material 320 . The binder is not particularly limited as long as it is commonly used, but may include, for example, at least one of Carboxymethyl cellulose (CMC) and Polytetrafluoroethylene Emulsion (PTFE). The binder may improve the viscosity of the conductive paste. When forming the conductive paste, it is possible to prevent the conductive material 320 from floating by adding a solvent having a hydrogen bond, for example, ethanol.

The negative active material 310 according to an embodiment of the present invention includes a core 311 and a shell 312 . The core 311 includes lead. The core 311 does not contain lead oxide. A shell 312 surrounds the core 311 . Shell 312 includes carbon. Lead as the core 311 and carbon as the shell 312 may be connected to each other by a covalent bond.

An anode active material according to an embodiment of the present invention may include carbon as a shell to prevent oxidation of Pb metal particles and have a large specific surface area. Lead oxide lowers the charge/discharge capacity of a battery compared to lead metal particles. Accordingly, when used in an anode or a secondary battery, the charge/discharge capacity of the battery can be improved and the lifespan can be extended.

In addition, the negative active material having a core-shell structure reduces resistance with the negative electrode plate and increases the time during which the initial discharge voltage is maintained constant, thereby improving the lifespan of the secondary battery.

Hereinafter, a method for manufacturing an anode active material according to an embodiment of the present invention will be described. Hereinafter, differences from the anode active material according to an embodiment of the present invention described above will be described in detail, and parts not described are based on the anode active material according to an embodiment of the present invention described above.

4 is a schematic flow chart sequentially illustrating a method for manufacturing an anode active material according to an embodiment of the present invention.

Referring to FIGS. 1 to 4 , the method of manufacturing the negative electrode active material 310 according to an embodiment of the present invention includes dissolving a lead precursor in distilled water to form a first solution (S100), dissolving a catalyst in distilled water, and Forming a second solution (S200), dispersing the carbon active material in a solvent to form a first dispersion solution (S300), providing a first solution and a second solution to the first dispersion solution to form a mixed solution Step (S400), sonication of the mixed solution (S500), and drying the ultrasonicated mixed solution to obtain a core 311 containing lead, and a shell 312 surrounding the core and containing carbon. ) and manufacturing an anode active material 310 including (S600).

A lead precursor is dissolved in distilled water to form a first solution (S100). The lead precursor includes, for example, at least one of PbNO ₃ , (CH ₃ SO ₃ ) ₂ Pb, PbCl ₂ , Pb(OAc) ₂ , Pb(NO ₃ ) ₂ , Pb(acac) ₂ , and PbCO ₃ . Lead included in the lead precursor forms the core 311 of the negative electrode active material 310 .

The catalyst is dissolved in distilled water to form a second solution (S200). The catalyst may promote the formation of the negative electrode active material 310 having a core-shell structure by promoting a covalent bond between lead and the carbon active material. The catalyst includes, for example, at least one of NaBH ₄ , NaH, trimethyl borate, and trisodium citrate.

A first dispersion solution is formed by dispersing the carbon active material in a solvent (S300). In the step of forming the first dispersion solution (S300), the carbon active material includes, for example, at least one of graphite and activated carbon (P60 and MSP-20).

In the step of forming the first dispersion solution (S300), the solvent includes, for example, at least one of ethanol and isopropyl alcohol.

The mixed solution is sonicated (S500). By ultrasonicating the mixed solution, lead and carbon active materials can be evenly dispersed in the mixed solution.

The ultrasonic treatment (S500) includes a first ultrasonic treatment of the mixed solution, and a second ultrasonic treatment of the mixed solution subjected to the first ultrasonic treatment.

The first sonication step may be performed for 40 to 60 minutes. If the first sonication step is performed for less than 40 minutes, the dispersion efficiency of the mixed solution may decrease, and if it is performed for more than 60 minutes, the dispersion efficiency does not increase any more.

The second ultrasonic treatment may be performed for 20 to 40 minutes. If the second sonication step is performed for less than 20 minutes, dispersion efficiency is lowered, and when performed for more than 40 minutes, aggregation between particles may occur due to heat generation.

The ultrasonically treated mixed solution is dried to prepare a negative electrode active material 310 including a lead-containing core 311 and a shell 312 surrounding the core 311 and carbon (S600). In the step of manufacturing the negative active material 310 ( S600 ), materials other than the negative active material 310 may be evaporated.

The step of preparing the negative electrode active material 310 (S600) may be performed by drying at 40 to 60° C. for 22 to 26 hours. When the temperature is less than the above range, materials other than the negative active material 310 are not sufficiently evaporated, and when the temperature exceeds the above range, defects may occur in the negative active material 310 .

The manufacturing method of the negative electrode active material 310 according to an embodiment of the present invention may further include washing the ultrasonicated mixed solution with at least one of distilled water and ethanol. In the washing step, impurities other than the negative electrode active material 310 may be washed. The washing step may be performed between the ultrasonic treatment step (S500) and the manufacturing step of the negative electrode active material 310 (S600).

In the method for manufacturing an anode active material according to an embodiment of the present invention, the yield of the anode active material can be improved by accelerating the reaction between lead and carbon active material through a catalyst. In addition, the anode active material prepared by the method for manufacturing an anode active material according to an embodiment of the present invention may include carbon as a shell to prevent oxidation of Pb metal particles and have a large specific surface area. Lead oxide lowers the charge/discharge capacity of a battery compared to lead metal particles. Accordingly, when used in an anode or a secondary battery, the charge/discharge capacity of the battery can be improved and the lifespan can be increased.

In addition, the negative active material having a core-shell structure reduces resistance with the negative electrode plate and increases the time during which the initial discharge voltage is maintained constant, thereby improving the lifespan of the secondary battery.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are merely examples to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

Example 1

Manufacture of negative electrode active material

PbNO ₃ was dissolved in distilled water to form a first solution. NaBH ₄ was dissolved in distilled water to form a second solution. 0.01 g of carbon active material P60 was dispersed in ethanol to form a first dispersion solution, and a mixed solution was formed by providing a first solution and a second solution to the first dispersion solution. The mixed solution was first sonicated for 50 minutes. The mixed solution subjected to the first ultrasonic treatment was subjected to the second ultrasonic treatment for 30 minutes. The mixed solution subjected to the second ultrasonic treatment was washed with distilled water and ethanol. 50? After drying in an oven for 24 hours, a negative electrode active material having lead as a core and carbon as a shell was formed.

cathode fabrication

0.5 g (60%) of the prepared anode active material, 0.11 g (13.3%) of graphite, and 0.11 g (13.3%) of carbon K were placed in a beaker. Carboxymethyl cellulose (CMC) and Polytetrafluoroethylene Emulsion (PTFE) were each quantified at 0.055 g (6.7%) and put into the beaker. 1ml of ethanol was put into the beaker and stirred with a spatula. After putting 2ml of distilled water in the beaker, it was stirred with a spatula on a hot plate until it became a dough, and the mixed paste was placed on a grid to shape it. The electrode plate was pressed so that the paste could be well distributed on the grid. After pressing, the paste that came out of the grid was collected and attached to the electrode plate, and then pressed again. This was dried at room temperature for 24 hours to form a negative electrode. When drying at a temperature higher than room temperature, cracks may occur on the surface of the negative electrode.

Manufacture of secondary battery

The prepared negative electrode was wrapped with AGM (Absorbent Glass Mat), and a positive electrode formed of PbO ₂ was superimposed on the side. This was placed in a battery case, the electrode was compressed using a PVC separator, and then sealed as much as possible to form a secondary battery having a size of 2X2.5mm.

Experimental Example 1

The negative active material of Example 1 was photographed with a transmission electron microscope and is shown in FIG. 5 . Referring to FIG. 5 , it can be seen that the negative electrode active material has a shell structure in which lead particle cores and carbon particles surround the lead particles. The size of the lead particles was 50 nm or less. In addition, the results of EDAX analysis of the anode active material of Example 1 are shown in FIG. 6 . Referring to FIG. 6 , since peaks of carbon (C) and lead (Pb) were both observed, it was confirmed that the anode active material contained lead and carbon.

Experimental Example 2

As a result of the SEM experiment, many pores were identified, so a BET experiment was conducted to confirm the size of the pores. The BET test results of the negative electrode active material of Example 1 are shown in FIG. 7 . The active material coated on graphite and MSP-20 carbon were measured using a specific surface analyzer (BEL, model name: Belsorp mini Ⅱ) to obtain the pore size and to confirm the specific surface area, using the BET (Brunauer-Emmett-Teller) formula. analyzed. Each sample used high-purity liquid nitrogen (N ₂ ) and measured the amount of gaseous nitrogen adsorbed according to the relative pressure (P/P ₀ ) in the pressure range of 1-102.77 kPa at 77K, and Barret-Joyner-Halende ( BJH) formula was used to confirm the development of the medieval pore.

7, (a) is a BET graph of normal carbon, and (b) is a BET graph of the anode active material of Example 1. It was confirmed that the specific surface area of the negative electrode active material of Example 1 was larger than that of normal carbon, which is expected because carbon surrounds the surface of the lead particle.

Experimental Example 3

8a and 8b are graphs of XRD analysis of the anode active material of Example 1; When a sample encounters X-rays, some of them cause diffraction, and since the diffraction angle and intensity are unique to the material structure, information related to the type and amount of crystalline materials contained in the sample can be obtained using the diffracted X-rays. An analysis method for obtaining information on the structure of a crystalline material is an X-ray diffractometer (XRD). In Experimental Example 3, X-ray diffraction (XRD, Rigaku Co., model name: D/MAX Ultima III) was measured in order to confirm the crystal structure of the negative electrode active material in powder form. Analysis conditions are shown in Table 1 below.

Theta X-ray 10° to 120° 40kV/40mA

Referring to Figures 8a and 8b, it can be seen that the peaks of Pb are identified at 31.36 (111), 36.38 (200), 52.26 (220), 62.36 (311), and 65.38 (222). The higher the peak value, the higher the crystallinity of Pb. The carbon forming the shell prevents oxidation of the Pb metal particles and improves the surface area of the negative electrode active material.

Experimental Example 4

9A and 9B are graphs of XPS analysis of the anode active material of Example 1. XPS measures the energy of photoelectrons emitted by incident characteristic X-rays on the surface of a sample, so that the composition and chemical bonding state of the sample surface can be known. In addition, the distribution with respect to depth can be measured by etching the surface with an ion beam. 9a and 9b, carbon was confirmed at 280 eV, and lead was confirmed at 136.5 eV and 138.5 eV, confirming that lead and carbon were chemically bonded. In addition, considering that the peak spacing of lead was 4.8 eV, it was confirmed that the state of lead was a Pb metal state. If the lead peak spacing exceeds 5 eV, it means the lead oxide form.

Experimental Example 5

10 is a graph showing resistance values of the negative electrode active material of Example 1 measured. The frequency range was 0.01 Hz to 3000 Hz, and resistance (impedance) was measured by applying a voltage of 5 mV. Impedance for each SOC was measured while increasing the state of charge to 0%, 25%, 50%, 75%, and 100%.

Contact resistance occurred between the electrolyte and the surface of the electrode, and it was confirmed that the resistance gradually decreased as the SOC increased, that is, as the charging of the secondary battery progressed. It was confirmed that a semicircular impedance graph appeared as a core-shell structure, that is, an electrical double layer reaction of carbon surrounding lead particles was formed. The discharge capacity was enhanced in the capacity test due to the formation of an electrical double layer reaction.

Experimental Example 6

11 (a) shows a graph of discharge by C-rate, and (b) is a graph showing voltage by capacity per volume of negative electrode active material. The capacity test was conducted for each C-rate (1C, 2C, 4C, 8C, 12C), and the experiment was conducted by setting the charging time to 4000 seconds, the charging current to 75mA, and the discharge cut-off to 0.5V. Referring to (a) of FIG. 11, it can be confirmed that the discharge capacity decreases as the C-rate increases, and a portion where the initial discharge voltage is kept constant, unlike the discharge curve of the conventional secondary battery, occurs. could If the content of lead and carbon is optimized, it can be predicted that the time during which the discharge voltage is maintained will increase. In addition, referring to (b) of FIG. 11 , it was confirmed that the secondary battery had a discharge capacity of 0.0165 Ah/cc per unit of 2X2.5 mm.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art can implement the present invention in other specific forms without changing its technical spirit or essential features. You will understand that there is Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

10: secondary battery 100: positive electrode
200: electrolyte 300: cathode
310: negative electrode active material 320: conductive material
311: core 312: shell

Claims (15)

delete delete delete delete delete delete dissolving a lead precursor in distilled water to form a first solution;
dissolving the catalyst in distilled water to form a second solution;
dispersing the carbon active material in a solvent to form a first dispersion solution;
forming a mixed solution by providing the first solution and the second solution to the first dispersion solution;
Sonicating the mixed solution; and
Drying the ultrasonically treated mixed solution to prepare a negative electrode active material including a lead-containing core and a shell surrounding the core and carbon. According to claim 7,
In the step of forming the first solution,
The lead precursor includes at least one of PbNO ₃ , (CH ₃ SO ₃ ) ₂ Pb, PbCl ₂ , Pb(OAc) ₂ , Pb(NO ₃ ) ₂ , Pb(acac) ₂ , and PbCO ₃ . A method for producing an active material. According to claim 7,
In the step of forming the second solution,
The catalyst is a method for producing a negative active material comprising at least one of NaBH ₄ , NaH, trimethyl borate, and trisodium citrate. According to claim 7,
In the step of forming the first dispersion solution,
The carbon active material is a method for producing a negative electrode active material comprising at least one of graphite and activated carbon. According to claim 7,
In the step of forming the first dispersion solution,
Wherein the solvent includes at least one of ethanol and isopropyl alcohol (Isopropylalcohol). According to claim 7,
The sonication step
first ultrasonicating the mixed solution; and
A method for producing a negative electrode active material comprising a second ultrasonic treatment of the mixed solution subjected to the first ultrasonic treatment. According to claim 12,
The first ultrasonic treatment step is performed for 40 to 60 minutes,
The second step of ultrasonic treatment is a method for producing a negative electrode active material that is performed for 20 to 40 minutes. According to claim 7,
The method of manufacturing a negative electrode active material further comprising the step of washing the mixed solution subjected to ultrasonic treatment with at least one of distilled water and ethanol. According to claim 7,
The step of preparing the negative active material is
A method for producing a negative active material that is performed by drying at 40 to 60 ° C. for 22 to 26 hours.

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