Negative electrode for lithium secondary battery and lithium secondary battery comprising same

Abstract

The negative electrode for a lithium secondary battery according to the present invention comprises: a negative electrode current collector; the negative electrode includes a negative electrode current collector, a negative electrode mixture layer on the negative electrode current collector, and the negative electrode mixture layer includes a silicon-based negative electrode active material and a binder, in which the binder is a polymer crosslinked body including an ester bond, and the melting enthalpy ([Delta] Hm) of the binder measured by a differential scanning calorimeter (DSC) may be 230 J / g or more.

Description

Technical Field

[0001] The present invention relates to a negative electrode for a lithium secondary battery and a lithium secondary battery including the same, and the negative electrode has improved adhesion ability and excellent life characteristics. Background Art

[0002] In recent years, with the increasing demand for electronic devices such as mobile devices, the development of lightweight and miniaturization of electrochemical cells (secondary batteries) is being expanded to improve the portability of electronic devices. In addition to this trend, as regulations related to automotive fuel efficiency and exhaust emissions become increasingly strict globally, the electric vehicle (EV) market is accelerating, and thus there is a need to develop a high-power and high-capacity battery for such electric vehicles.

[0003] Examples of secondary batteries include lithium secondary batteries, nickel-cadmium batteries, nickel-metal hydride batteries, etc. Among them, lithium secondary batteries have a high operating voltage and energy density per unit weight, and are advantageous for charging speed and lightweight, and thus are actively being developed and applied.

[0004] Among them, a lithium secondary battery may include: an electrode assembly including a positive electrode, a negative electrode, and a separator (separating membrane); and an electrolyte impregnating the electrode assembly. The lithium secondary battery may further include an exterior material accommodating the electrode assembly and the electrolyte, and the exterior material may be, for example, a pouch, a prismatic, or a cylindrical can.

[0005] In recent years, with the expansion of the application targets of the lithium secondary battery, lithium secondary batteries with higher capacity and power are being developed. For example, research is being conducted on positive electrode materials or negative electrode materials that can provide higher capacity.

[0006] As the negative electrode material of a lithium secondary battery, a carbon-based negative electrode material having excellent cycle characteristics and a theoretical capacity of 372 mAh / g is usually used. However, as the high-capacity of secondary batteries such as medium and large secondary batteries is gradually required, inorganic-based negative electrode materials such as silicon (Si), germanium (Ge), tin (Sn), or antimony (Sb) that can replace the theoretical capacity of the carbon-based negative electrode material and have a capacity of 500 mAh / g or more have attracted much attention. Among these inorganic-based negative electrode materials, silicon-based negative electrode materials exhibit a very high lithium binding amount.

[0007] However, the silicon-based material may cause shrinkage / swelling phenomena during repeated charge / discharge processes, and thus may cause peeling of the negative electrode active material layer, side reactions with the electrolyte, etc. In addition, mechanical defects and chemical defects may occur during high-temperature storage or high-temperature operation, thereby deteriorating the life characteristics of the secondary battery.

[0008] In addition, the negative electrode is usually manufactured by mixing a negative electrode active material such as silicon with a conductive material and a binder to prepare a negative electrode mixture layer, and then coating the mixture layer on an electrode current collector such as a copper foil, followed by drying and rolling to manufacture the negative electrode. SUMMARY OF THE INVENTION

[0009] (I) Technical problems to be solved

[0010] According to one aspect of the present invention, a negative electrode for a lithium secondary battery can be provided, which can suppress the expansion of a silicon-based negative electrode active material during charge and discharge of the lithium secondary battery, improve the adhesion between the negative electrode mixture layer and the negative electrode current collector, and can suppress an increase in resistance according to charge and discharge of the battery and improve the battery life even when manufactured with a high capacity and high energy density.

[0011] According to another aspect of the present invention, a lithium secondary battery including the negative electrode for a lithium secondary battery can be provided.

[0012] (II) Technical solutions

[0013] The negative electrode for a lithium secondary battery according to a specific embodiment includes: a negative electrode current collector; a negative electrode mixture layer located on the negative electrode current collector, and the negative electrode mixture layer contains a silicon-based negative electrode active material and a binder, the binder is a polymer crosslinking body containing an ester bond, and the melting enthalpy (ΔH m ) measured by a differential scanning calorimeter (DSC) is 230 J / g or more.

[0014] The binder may have a first absorbance peak appearing at 1725 - 1745 cm in the FT-IR spectrum -1 and a second absorbance peak appearing at 1745 - 1760 cm. -1

[0015] The binder may be a crosslinking body of polyvinyl alcohol (PVA) and polyacrylic acid (PAA).

[0016] The molar ratio of polyvinyl alcohol to polyacrylic acid contained in the crosslinking body may be 1:0.6 to 1:1.2.

[0017] The binder may further contain one or more polymers selected from polyvinyl alcohol, polyacrylic acid, polyvinyl acetate, polyacrylonitrile, polyacrylamide, and polyvinyl acetate.

[0018] ​The silicon-based anode active material may include silicon (Si), silicon alloy, silicon oxide, silicon-carbon (Si-C) composite, silicon alloy (Si-alloy)-based carbon composite, or a mixture thereof.

[0019] The anode mixture layer may further include a carbon-based anode active material.

[0020] The carbon-based anode active material may be one or more selected from artificial graphite and natural graphite.

[0021] The anode mixture layer may further include a conductive material. The conductive material may be one or more selected from single-walled carbon nanotube (SWCNT), thin-walled carbon nanotube (TWCNT), multi-walled carbon nanotube (MWCNT), carbon fiber, and graphene.

[0022] The thickness of the anode mixture layer may be 80 - 130 μm.

[0023] A lithium secondary battery according to a specific embodiment includes: the anode for the lithium secondary battery described above; a cathode; and a separator disposed between the anode and the cathode.

[0024] (III) Beneficial Effects

[0025] According to an embodiment of the present invention, expansion of the silicon-based anode active material during charge and discharge of the lithium secondary battery can be suppressed.

[0026] According to an embodiment of the present invention, the life characteristics of the lithium secondary battery can be improved.

[0027] According to another embodiment of the present invention, a battery with high capacity and high energy density having excellent life characteristics can be manufactured. Description of the Drawings

[0028] Figure 1 is a graph showing a differential scanning calorimetry (DSC) curve of an adhesive sample manufactured in an example of a specific embodiment.

[0029] Figure 2 is a comparison graph of the values of the melting enthalpy (ΔH m ) of an adhesive sample manufactured in an example of a specific embodiment.

[0030] Figure 3 is a graph showing the FT-IR analysis results of an adhesive sample manufactured in an example of a specific embodiment.

[0031] Figure 4 It is a graph showing the relative intensity of the FT-IR analysis results of an adhesive sample manufactured in an example showing a specific embodiment.

[0032] Figure 5 It is a graph showing the SAICAS analysis results of a negative electrode manufactured in an example showing a specific embodiment. Best Mode for Carrying Out the Invention

[0033] Hereinafter, the present invention will be described in detail (with reference to the accompanying drawings). However, this is merely exemplary, and the present invention is not limited to the specific embodiments described exemplarily.

[0034] Negative electrode for lithium secondary battery

[0035] A specific embodiment provides a negative electrode for a lithium secondary battery, which includes: a negative electrode current collector; a negative electrode mixture layer located on the negative electrode current collector, and the negative electrode mixture layer contains a silicon-based negative electrode active material and an adhesive, the adhesive is a polymer crosslinking body containing an ester group, and the melting enthalpy (ΔH m ) measured by a differential scanning calorimeter (DSC) is 230 J / g or more.

[0036] The silicon-based negative electrode active material may include silicon (Si), a silicon alloy, a silicon oxide, a silicon-carbon (Si-C) composite, a silicon alloy-based-carbon composite, or a mixture thereof. Compared with the existing silicon oxide-based active material, the Si-C composite has high-capacity and low-resistance characteristics. In addition, since silicon exists inside the structure similar to graphite in the Si-C composite, it is possible to alleviate the phenomenon of electrode crack generation due to volume expansion of the active material containing silicon-based oxide, and to ensure conductivity. In addition, the silicon-based active material may include SiO x (0 < x < 2).

[0037] Therefore, a specific embodiment can improve the adhesion of the adhesive and ensure the fast charging and / or general (room temperature) life characteristics of the electrode by including an adhesive that is a polymer crosslinking body containing an ester bond, and the melting enthalpy (ΔH m ) measured by a differential scanning calorimeter (DSC) is 230 J / g or more.

[0038] The melting enthalpy (ΔH m) It can be 230 J / g or more, specifically it can be 230 - 300 J / g, 240 - 290 J / g, or 250 - 260 J / g.

[0039] By adjusting the melting enthalpy of the adhesive to the above range, the crystallinity of the polymer can be effectively controlled, so that excellent adhesion characteristics can be obtained, and the life characteristics can be improved due to the reduction of detachment.

[0040] The differential scanning calorimeter (DSC) can specifically be a modulated differential scanning calorimeter (MDSC), and more specifically a temperature-modulated differential scanning calorimeter (TMDSC).

[0041] Specifically, the melting enthalpy can be measured by scanning at a heating rate of 10 °C using the differential scanning calorimeter (DSC) mode. More specifically, the melting enthalpy can be measured by performing one scan (1st scan) or two scans (2nd scan) using the differential scanning calorimeter (DSC). In the present invention, the melting enthalpy is measured by performing one scan on the polyester film using DSC.

[0042] From the heat flow curve obtained by scanning, the glass transition temperature (Tg, Glass Transition Temperature), crystallization temperature (Tc, Crystallization Temperature), and melting temperature (Tm, Melting Temperature) can be determined.

[0043] Specifically, in the heat flow curve obtained by scanning, the first endothermic temperature can be the glass transition temperature (Tg), the exothermic temperature measured after the glass transition temperature (Tg) can be the crystallization temperature (Tc), and the endothermic temperature measured after the crystallization temperature (Tc) can be the melting temperature (Tm).

[0044] At this time, the integral value at the melting temperature (Tm) is calculated as the melting enthalpy. Specifically, the melting enthalpy is the energy in the interval where endotherm occurs in the heat flow curve of the differential scanning calorimeter, and the melting enthalpy is calculated by setting the trend line from the melting start temperature to the complete melting temperature as the baseline and converting the integral value of the peak according to the baseline.

[0045] In addition, the crystallinity of the binder can be from 10% to 80%. In a specific embodiment, when the binder has a crystallinity within the above range, the resistance of the negative electrode can be reduced by controlling the electrolyte absorption rate of the binder resin, while preventing the reduction in the adhesion between the negative electrode current collector and the negative electrode mixture layer caused by the curing of the binder.

[0046] In the case of a binder that satisfies the above range, it can have sufficient crystallinity so as not to reduce the resistance characteristics. Therefore, this result can ensure the improvement effect of the adhesion between the negative electrode current collector and the negative electrode mixture layer while ensuring low resistance characteristics.

[0047] In a specific embodiment, the crystallinity is calculated by dividing the measured melting enthalpy (ΔH m ) value in the differential scanning calorimeter by the melting enthalpy (ΔH m ) value of theoretically complete crystallization (crystallinity of 100%) and expressed as a percentage (%). Among them, for the melting enthalpy value of theoretically complete crystallization, for known polymers, it can be found and used in the polymer handbook, and for unknown substances or newly synthesized substances, it can be calculated by the extrapolation method obtained by extending the crystallinity at two or more points.

[0048] The binder of a specific embodiment can have a first absorbance peak appearing at 1725 - 1745 cm -1 and a second absorbance peak appearing at 1745 - 1760 cm -1 in the FT-IR spectrum. The absorbance peaks of the present invention are measured based on adjusting the absorbance in the range of 2000 - 600 cm -1 in the FT-IR spectrum analysis region to 0 to correct the baseline.

[0049] The first absorbance peak appearing at 1725 - 1745 cm -1 can refer to the peak appearing in the ester functional group of the binder in the FT-IR spectrum obtained by the FT-IR spectrophotometer.

[0050] In addition, the second absorbance peak appearing at 1745 - 1760 cm -1 can refer to the peak appearing in the ester functional group connected to a ketone in the FT-IR spectrum obtained by the FT-IR spectrophotometer.

[0051] When the peaks observed when measuring the FT-IR of the binder of a specific embodiment satisfy the above range, it can be confirmed that the crosslinking of the composition contained in the binder has proceeded. Therefore, the adhesion between the negative electrode mixture layer and the negative electrode current collector to which the binder of a specific embodiment is applied can be improved.

[0052] The binder of a specific embodiment may be a crosslinked product of polyvinyl alcohol (PVA) and polyacrylic acid (PAA). Through the interaction between the carboxyl groups contained in the polyacrylic acid and the electrolyte, a solid electrolyte interphase (SEI) layer can be formed on the surface of the silicon-based active material. Therefore, irreversible decomposition of the electrolyte can be blocked, and at the same time, excessive swelling of the silicon-based active material can be suppressed. In addition, the binder contains polyvinyl alcohol at the same time, so that the formation of the SEI layer can be further promoted through hydrophilic interaction.

[0053] The molar ratio of polyvinyl alcohol to polyacrylic acid contained in the binder may be from 1:0.6 to 1:1.2, specifically from 1:0.8 to 1:1. When the molar ratio of polyacrylic acid to polyvinyl alcohol contained in the binder is not within the above range, the effect of the binder brought about by crosslinking is reduced, so it may act as a resistance.

[0054] The binder may further contain one or more polymers selected from polyvinyl alcohol, polyacrylic acid, polyvinyl acetate, polyacrylonitrile, polyacrylamide, and polyvinyl acetate.

[0055] The negative electrode mixture layer may contain a negative electrode active material. The negative electrode active material may use a material that can adsorb and desorb lithium ions. For example, the negative electrode active material may use carbon-based materials such as crystalline carbon, amorphous carbon, carbon composites, and carbon fibers; lithium metal; lithium alloys; silicon (Si)-containing substances or tin (Sn)-containing substances, etc.

[0056] Examples of the amorphous carbon may include hard carbon, soft carbon, coke, mesocarbon microbead (MCMB), mesophase pitch-based carbon fiber (MPCF), etc.

[0057] Examples of the crystalline carbon may include graphite-based carbons such as natural graphite, artificial graphite, graphitized coke, graphitized MCMB, and graphitized MPCF.

[0058] The lithium metal may include pure lithium metal or lithium metal formed with a protective layer for suppressing dendrite growth or the like. In one embodiment, the lithium metal-containing layer deposited or coated on the negative electrode current collector may be used as the negative electrode active material layer. In one embodiment, the lithium thin film layer may also be used as the negative electrode active material layer.

[0059] The elements contained in the lithium alloy may include aluminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium, indium, etc.

[0060] The silicon-containing material may provide further enhanced capacity characteristics. The silicon-containing material may include silicon (Si), SiO x (0 < x < 2), metal-doped SiO x (0 < x < 2), silicon-carbon composite, etc. The metal may include lithium and / or magnesium, and the metal-doped SiO x (0 < x < 2) may include metal silicate.

[0061] The conductive material is used to impart conductivity to the electrode and maintain the structure of the electrode, etc. A conductive material that does not undergo side reactions with other components of the secondary battery and has conductivity can be used. Exemplarily, graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal cracking carbon black, carbon fiber; metal powders or metal fibers such as copper, nickel, aluminum, silver; conductive whiskers such as zinc oxide, potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, etc. can be used. One of them can be used alone or a mixture of two or more can be used. Specifically, it may include one or more selected from single-walled carbon nanotubes (SWCNT), thin-walled carbon nanotubes (TWCNT), multi-walled carbon nanotubes (MWCNT), carbon fiber, and graphene.

[0062] The thickness of the negative electrode mixture layer may be 80 - 130 μm, specifically 100 - 120 μm. When the thickness of the negative electrode mixture layer is less than 80 μm, scratching of the active material or tearing of the current collector may occur during the coating process. When the thickness of the negative electrode mixture layer exceeds 130 μm, the effect of the invention may be reduced due to the use of an excessive amount of binder.

[0063] The negative electrode of a specific embodiment can be manufactured by mixing a negative electrode active material, a conductive material, and a binder to form a negative electrode mixture layer, then coating the negative electrode mixture layer on the negative electrode current collector, and drying and calendering.

[0064] At this time, the drying may include primary drying and secondary drying. The temperature of the primary drying may be 25°C or higher, specifically 80°C or higher, more specifically 100°C or higher, and may be 200°C or lower, specifically 180°C or lower, more specifically 150°C or lower. When the primary drying temperature of the negative electrode mixture layer is within the above range, the adhesion between the negative electrode mixture layer and the negative electrode current collector can be improved.

[0065] In addition, the temperature of the secondary drying may be 25°C or higher, specifically 80°C or higher, more specifically 100°C or higher, and may be 200°C or lower, specifically 180°C or lower, more specifically 150°C or lower. When the secondary drying temperature of the negative electrode mixture layer is within the above range, the adhesion between the negative electrode mixture layer and the negative electrode current collector can be improved.

[0066] A lithium secondary battery according to a specific embodiment includes: the negative electrode for the lithium secondary battery; a positive electrode; and a separator disposed between the negative electrode and the positive electrode.

[0067] The lithium secondary battery can be made, for example, into a cylindrical shape using a can, a prismatic shape, a pouch type, or a coin shape. Detailed Description

[0068] Examples

[0069] Hereinafter, with reference to specific experimental examples, the examples of the present invention will be further described. The examples and comparative examples included in the experimental examples are only for illustrating the present invention and do not limit the claims. Various changes and modifications can be made to the examples within the scope and technical concept of the present invention, which will be obvious to those skilled in the art, and such variations and modifications are naturally within the scope of the claims.

[0070] 1. Evaluation of the Adhesive

[0071] (1) Preparation of the Adhesive Sample

[0072] Example 1

[0073] An aqueous solution containing 49% by weight of PAA and 51% by weight of PVA was placed in a weighing dish and subjected to primary drying at 120°C for 2 hours to prepare a solid-phase PAA-PVA copolymer. Thereafter, the solid-phase PAA-PVA copolymer was subjected to secondary drying in an oven at 100°C for 2 hours to manufacture an adhesive sample.

[0074] Example 2

[0075] An adhesive sample was manufactured by the same method as in Example 1, except that the secondary drying temperature was set at 120 °C.

[0076] Comparative Example 1

[0077] An adhesive sample was manufactured by the same method as in Example 1, except that the secondary drying temperature was set at 25 °C.

[0078] Comparative Example 2

[0079] An adhesive sample was manufactured by the same method as in Example 1, except that the secondary drying temperature was set at 60 °C.

[0080] Comparative Example 3

[0081] An adhesive sample was manufactured by the same method as in Example 1, except that the secondary drying temperature was set at 80 °C.

[0082] Comparative Example 4

[0083] An adhesive sample was manufactured by the same method as in Example 1, except that the secondary drying temperature was set at 150 °C.

[0084] Comparative Example 5

[0085] An adhesive sample was manufactured by the same method as in Example 1, except that the secondary drying temperature was set at 200 °C.

[0086] (2) Measurement of the enthalpy of fusion (ΔH m )

[0087] The adhesive samples manufactured according to Example 1, Example 2, and Comparative Examples 1 to 4 were placed in a differential scanning calorimeter (Q2000, manufacturer: TA Instruments), and scanned at a heating rate of 10 °C using the differential scanning calorimeter (DSC) mode.

[0088] In the heat flow curve obtained by scanning, the first endothermic temperature is the glass transition temperature (Tg), the exothermic temperature measured after the glass transition temperature (Tg) is the crystallization temperature (Tc), and the endothermic temperature measured after the crystallization temperature (Tc) is measured as the melting point (Tm).

[0089] Figure 1 is a DSC curve showing the differential scanning calorimeter (DSC) analysis results of the adhesive samples manufactured according to Example 1, Example 2, and Comparative Examples 1 to 4, Figure 2 is based on Figure 1 comparison chart of the values of the enthalpy of fusion (ΔH m ) of the DSC curve.

[0090] With reference to Figure 2 the results of Example 1 and Example 2, it can be confirmed that the melting enthalpy (ΔH m ) is 230 J / g or more and the crystallinity is high. Therefore, the degree of crystallization of the polymer contained in the binder is high.

[0091] On the other hand, with reference to the results of Comparative Example 1 to Comparative Example 4, it can be confirmed that since the melting enthalpy (ΔH m ) is less than 230 J / g and the crystallinity is low, the degree of crystallization of the polymer contained in the binder is low.

[0092] (3) FT-IR analysis

[0093] Figure 3 The measurement results of Fourier-transform infrared spectroscopy (FT-IR) of the binder samples manufactured according to Example 1, Example 2, Comparative Example 4, and Comparative Example 5 are shown, Figure 4 showing the relative intensities of the FT-IR measurement results according to Figure 3 .

[0094] With reference to Figure 3 the results, it can be confirmed that as the secondary drying temperature increases, the 1725 - 1745 cm -1 wavelength region representing the ester bond and the 1745 - 1760 cm -1 wavelength region representing the ester bond connected to the ketone increase. That is, it can be confirmed that as the secondary drying temperature increases, the crosslinking degree of the polymer contained in the binder increases.

[0095] 2. Evaluation of the negative electrode

[0096] (1) Fabrication of the negative electrode

[0097] Example 3

[0098] Graphite and Si negative electrode active material, SWCNT conductive material, and an aqueous solution binder containing PAA and PVA in a weight ratio of 49:51 were mixed in a weight ratio of 97.75:0.25:2 to fabricate a negative electrode mixture layer.

[0099] The negative electrode mixture layer was uniformly coated on a copper foil at a loading weight of 8 mg / cm², and dried twice at a primary drying temperature of 120 °C and a secondary drying temperature of 100 °C, and then calendered to fabricate a negative electrode.

[0100] Example 4

[0101] The negative electrode was fabricated in the same manner as in Example 3, except that the secondary drying temperature was set at 120 °C.

[0102] Comparative Example 6

[0103] The negative electrode was fabricated in the same manner as in Example 3, except that the secondary drying was not performed.

[0104] Comparative Example 7

[0105] The negative electrode was fabricated in the same manner as in Example 3, except that the secondary drying temperature was set at 150 °C.

[0106] Comparative Example 8

[0107] The negative electrode was fabricated in the same manner as in Example 3, except that the secondary drying temperature was set at 200 °C.

[0108] (2) Analysis of SAICAS

[0109] Figure 5 The SAICAS analysis results of the negative electrodes fabricated according to Example 3, Example 4, and Comparative Examples 6 to 8 are shown.

[0110] Referring to Figure 5 the results, crystallization was performed at a secondary drying temperature of 100 - 120 °C, resulting in excellent adhesion.

[0111] On the other hand, it was confirmed that when the secondary drying was not performed or when the secondary drying was performed at a high temperature, the temperature for crystallization was deviated, resulting in a decrease in adhesion.

[0112] The above description is merely an example of applying the principles of the present invention, and other configurations may be further included without departing from the scope of the present invention.

Claims

1. A negative electrode for a lithium secondary battery, which comprises: a negative electrode current collector; a negative electrode mixture layer, the negative electrode mixture layer being located on the negative electrode current collector, and the negative electrode mixture layer containing a silicon-based negative electrode active material and a binder, Among them, the binder is a polymer crosslinking body containing an ester bond, and the melting enthalpy ΔH of the binder measured by a differential scanning calorimeter (DSC) m is 230 J / g or more.

2. The negative electrode for a lithium secondary battery according to claim 1, wherein, The adhesive has a first absorbance peak appearing at 1725 - 1745 cm in the FT-IR spectrum and a second absorbance peak appearing at 1745 - 1760 cm -1 . -1 .

3. The negative electrode for a lithium secondary battery according to claim 1, wherein, the binder is a cross-linked body of polyvinyl alcohol (PVA) and polyacrylic acid (PAA).

4. The negative electrode for a lithium secondary battery according to claim 3, wherein, the molar ratio of polyvinyl alcohol to polyacrylic acid contained in the cross-linked body is 1:0.6 to 1:1.

2.

5. The negative electrode for a lithium secondary battery according to claim 1, wherein, the binder further contains one or more polymers selected from polyvinyl alcohol, polyacrylic acid, polyvinyl acetate, polyacrylonitrile, polyacrylamide, and polyvinyl acetate.

6. The negative electrode for a lithium secondary battery according to claim 1, wherein, the silicon-based negative electrode active material contains silicon (Si), a silicon alloy, a silicon oxide, a silicon-carbon (Si-C) composite, a silicon alloy-based-carbon composite, or a mixture thereof.

7. The negative electrode for a lithium secondary battery according to claim 1, wherein, the negative electrode mixture layer further contains a carbon-based negative electrode active material.

8. The negative electrode for a lithium secondary battery according to claim 7, wherein, the carbon-based negative electrode active material is one or more selected from artificial graphite and natural graphite.

9. The negative electrode for a lithium secondary battery according to claim 1, wherein, the negative electrode mixture layer further contains a conductive material.

10. The negative electrode for a lithium secondary battery according to claim 9, wherein, the conductive material is one or more selected from single-walled carbon nanotubes (SWCNT), thin-walled carbon nanotubes (TWCNT), multi-walled carbon nanotubes (MWCNT), carbon fibers, and graphene.

11. The negative electrode for a lithium secondary battery according to claim 1, wherein, the thickness of the negative electrode mixture layer is 80 - 130 μm.

12. A lithium secondary battery, which comprises: the negative electrode for a lithium secondary battery according to any one of claims 1 to 11; a positive electrode; and a separator disposed between the negative electrode and the positive electrode.

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