KR100578868B1 - Negative material for lithium secondary battery and negative electrode and lithium secondary battery comprising same - Google Patents

Abstract

The present invention is the first carbon powder particles having a form in which the plate-shaped particles are orientated and laminated in the plane direction and have a first granulated form; And a negative active material having a structure in which second fine carbon powder particles are secondary granulated on a surface of the carbon powder particles.

Since the negative electrode active material of the present invention has high density and high compressive strength, it is possible to manufacture a high density electrode plate and increase the capacity of a battery.

Assembly, carbon powder, compressive strength, high density electrode plate, lithium secondary battery

Description

A negative electrode active material for a lithium secondary battery, and a negative electrode and a lithium secondary battery including the same TECHNICAL FIELD

1 is a view schematically showing the structure of a negative electrode active material according to an embodiment of the present invention.

2 is a perspective view illustrating an example of a lithium secondary battery.

* Description of the symbols for the main parts of the drawings *

1: lithium secondary battery 2: negative electrode

3: anode 4: separator

5: battery container 6: sealing member

10: negative electrode active material 20: first carbon powder particles

30: second carbon powder particles

[Industrial use]

The present invention relates to a negative electrode active material for a lithium secondary battery, and a negative electrode and a lithium secondary battery comprising the same, and more particularly, a negative electrode active material for a lithium secondary battery that can provide a high-density electrode plate having excellent compressive strength of particles and comprising the same It relates to a negative electrode and a lithium secondary battery.

[Prior art]

Lithium secondary batteries are manufactured by reversibly inserting and detaching lithium ions as a positive electrode and a negative electrode, and filling an organic or polymer electrolyte between the positive electrode and the negative electrode, and lithium ions are inserted / Electrical energy is generated by oxidation and reduction reactions when desorption.

As a cathode active material of a lithium secondary battery, a chalcogenide compound is used, and examples thereof include LiCoO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiNi _1-x Co _x O ₂ (0 <x <1) Composite metal oxides, such as these, are used.

Lithium metal is used as the negative electrode active material, but when lithium metal is used, a battery short circuit occurs due to the formation of dendrite, which is a risk of explosion and is being replaced with a carbon-based material instead of lithium metal. The carbon-based active material used as a negative electrode active material of a lithium secondary battery includes crystalline carbon such as natural graphite and artificial graphite, and amorphous carbon such as soft carbon and hard carbon. The amorphous carbon has a large capacity, but has a problem in that irreversibility is large during charging and discharging. Natural graphite is typically used as the crystalline carbon, and has a theoretical limit capacity of 372 mAh / g, which is used as a negative electrode active material due to its high capacity, but has a serious life deterioration.

Generally, the negative electrode for lithium secondary batteries is manufactured by mixing and stirring a carbon material which is a negative electrode active material as needed, and a binder, stirring, and preparing a slurry, apply | coating this slurry to a metal electrical power collector, and drying it. At this time, it is common to perform a rolling process to compress the active material powder to the current collector, to uniform the electrode electrode plate thickness, and to increase the electrode plate capacity. However, during the rolling process of the electrode plate, the carbon material is crushed and cracked, resulting in non-uniformity of the electrode plate, and the reaction with the electrolyte is nonuniform, resulting in a decrease in the lifetime of the electrode plate. In addition, due to the crushing cracks, new edges are exposed as it is, so that the side reaction with the electrolyte becomes large, and the viscosity of the electrolyte is very high at a low temperature of -20 ° C. The electrolyte is reduced, resulting in a decrease in low temperature discharge characteristics.

The present invention is to solve the problems of the prior art, to provide a negative active material for a lithium secondary battery and a negative electrode and a lithium secondary battery including the same, which can provide a high-density electrode plate having excellent compressive strength of particles.

In order to achieve the above object, the present invention is the first carbon powder particles having a form in which the plate-shaped particles are orientated and laminated in the plane direction, the first assembled; And a negative active material for a lithium secondary battery having a structure in which second fine carbon powder particles are secondary granulated on a surface of the carbon powder particles.

The present invention also provides a negative electrode comprising the negative electrode active material.

The present invention also provides a lithium secondary battery comprising the negative electrode.

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

As illustrated in FIG. 1, the negative electrode active material 10 of the present invention has fine carbon powder particles on the surface of the first carbon powder particles 20 having a form in which the plate-shaped particles are aligned and stacked in the plane direction to form a primary granulated body. 30 is assembled.

The first carbon powder particles have a form in which the plate-shaped particles are aligned in the plane direction to be first assembled, and each particle reflects different polarized light. The first carbon powder particles are preferably spherical or quasi-spherical natural graphite or artificial graphite having a particle diameter of 10 µm or more, preferably 15 to 25 µm. The first carbon powder particles have an intensity ratio between the (110) plane and the (002) plane by X-ray diffraction analysis of 0.2 or less, preferably 0.002 to 0.2.

The second fine carbon powder particles are powders of fine powder generated in the process of pulverizing the first carbon powder particles, and have an average length or an average particle diameter of 5 µm or less, preferably 0.5 to 3 µm. The shape of the second fine carbon powder particles is not particularly limited but may be fibrous, spherical, amorphous or flake shaped.

The second fine carbon powder particles may have some or all of them in an amorphous or turbostratic structure. The second fine carbon powder particles form an assembly on the surface of the first carbon powder particles, thereby minimizing micropores in the first carbon powder particles, thereby obtaining a high-density negative electrode active material. On the other hand, the fine pores on the surface of the first carbon powder particles are developed to increase the absolute impregnation amount of the electrolyte, thereby improving the high rate characteristic and the low temperature characteristic. However, when the micropores are present in the entire active material, there is a problem in that the high surface area of the active material is easily compressed to increase the specific surface area of the active material in the electrode plate, and thus a new edge surface protrudes, resulting in an electrolyte side reaction. In the present invention, since the porosity exists only on the surface of the negative electrode active material, it is not easily broken even in the process of rolling into the electrode plate, thereby maintaining the active material form, and thus, an electrode plate having excellent swelling suppression characteristics can be manufactured because there is no electrolyte side reaction.

In addition to the second fine carbon powder particles, an amorphous carbon coating layer may be further formed on the surface of the first carbon powder particles. The amorphous carbon coating layer is present in an amount of 5 to 30 parts by weight, preferably 5 to 15 parts by weight, based on 100 parts by weight of the first carbon powder particles.

The negative electrode active material according to the present invention has a ratio of the major axis to the minor axis of 4 or less, preferably in the range of 1 to 3. The porosity occupied by pores of 0.5 μm or less in the negative electrode active material is 10% to 40%, preferably 15 to 40%, more preferably 10 to 35%. Further, the microporosity occupied by pores of 0.1 µm or less is 12% or less, preferably 3 to 10%.

Usually, due to the rolling process of the electrode plate, the microporosity of the electrode plate is generally reduced than the microporosity of the active material. The microporosity of the active material of the present invention is almost 2.0 times or less, preferably 1.1 to 1.5, of the electrode plate. .

In the electrode plate to which the negative electrode active material is applied, pores of 10 to 100 μm serve to improve the rate of moisture in the electrolyte and the rate of delivery of lithium ions. When the electrode plate is manufactured from a conventional carbon material, the porosity occupied by the pores of 10 to 100 μm is significantly reduced. However, in the present invention, the porosity occupied by the pore of 10 to 100 ㎛ is present in 30 to 60%, preferably 35 to 50%, so that the electrolyte discharge and flow passage is excellent, thereby improving the low-temperature discharge characteristics as the lithium ion transfer characteristics are improved. do.

The negative active material of the present invention is a high density carbon material having a tap density of 1.0 g / cc or more, preferably 1.1 to 1.30 g / cc, and an apparent density of 0.6 to 1.0 g / cc. In addition, the ratio of the tap density to the apparent density is 30% or more.

In addition, the specific surface area measured by the BET method is 2.0 to 4.0 m ³ / g. In addition, since the compressive strength of the negative electrode active material is in the range of 15 Mpa or more, preferably 15 to 45 Mpa, damage of the active material hardly occurs even in the rolling process of the electrode plate.

Hereinafter, a manufacturing process of the negative electrode active material will be described.

First, the carbon material is spherical or quasi-spherical by removing the mole portion or protrusions of the carbon material through the first mechanical mechanical grinding process. The carbon material may be natural graphite, artificial graphite, graphitized precursor, and the like, and the graphitized precursor may include graphitized carbon fiber and graphitized mesocarbon microbeads.

The spherical or pseudo spherical particles are formed by the primary mechanical mechanical grinding process, and at the same time, primary granulation is performed, and fine carbon powder particles are formed in this process. At this time, inside the carbon material, small cracks are present between the grains having an orientation in a certain direction, thereby changing the grain orientation. At the same time, fluidity between grains is ensured through cracks caused by fine particulate impurities present therein.

In the present invention, the fine carbon particles and the carbon material are secondarily assembled through the second mechanical mechanical grinding process that imparts interfacial friction and shear force. In the second granulation process, the plate-shaped particles are aligned in the plane direction. The van der Waals force between the particle planes is maximized by the very strong inter-plane frictional stress, and the interlocking of the uneven portion of the surface is maximized, so that a multi-layered spherical or pseudo-spherical powder is produced by dry assembly. The fine carbon particles are secondly assembled on the surface of the carbon material so that the fine carbon particles coat the plate-like carbon material. At this time, the fine carbon powder particles are assembled while forming micropores in a nonuniform direction. In the present invention, the granulation process is all made dry.

The mechanical mechanical grinding process utilizes the forces of compression, impact, shear, and friction. All grinding processes do not use any specific force but all four forces are used. This may vary depending on the design characteristics of the equipment or the operating conditions. In the process of smoothing the surface of particles through primary mechanical operation, the shape of the particles is refined mainly by the force generated by compression and impact. Examples of the typical grinding machine operation equipment include rotamille, ACM mill, pin mill, jet mill, and the like. For the secondary assembly and surface fine powder attachment, the machine operation equipment that provides shearing force and compression friction force is mechanofujeon, hive. And equipment such as redidation.

Further fine carbon powder particles may be further added during the secondary granulation process. In addition, an amorphous carbon precursor may be added during the second granulation process to be assembled to the plate-shaped particles together with the fine carbon particles. Examples of the amorphous carbon precursor include mesophase pitch, coal-based pitch, petroleum-based pitch, low molecular weight heavy oil, and the like. Such amorphous carbon precursor may be added in an amount of 5 to 30 parts by weight based on 100 parts by weight of the carbon material.

 The assembly thus formed is subjected to heat treatment to prepare the negative electrode active material of the present invention. The heat treatment step is preferably performed at 1000 ° C or higher, preferably 1200 to 2400 ° C. If the heat treatment temperature is less than 1000 ° C., there is a problem that the removal of impure heterogeneous elements is not sufficient, which is not preferable.

The present invention also provides a negative electrode comprising the negative electrode active material. The negative electrode is prepared by applying a slurry containing a negative electrode active material and a binder resin to a metal current collector, followed by drying and rolling.

Since the negative electrode active material of the present invention has high density and compressive strength, the negative electrode active material may be manufactured in a high density electrode plate of 1.5 g / cc to 2.0 g / cc, preferably 1.8 to 2.0 g / cc, when manufacturing the electrode plate. Even if such a high density electrode plate is manufactured, a sufficient electrolyte solution impregnation path can be maintained, thereby providing a battery of high capacity.

As the binder resin, all binder resins conventionally used in lithium secondary batteries may be used, and examples thereof include polyvinylidene fluoride, carboxymethyl cellulose, methyl cellulose and sodium polyacrylate. Examples of the metal current collector include punching metal, ex punching metal, gold foil, foamed metal, reticulated metal fiber sintered body, nickel foil, and copper foil.

The negative electrode of the present invention may further include a conductive assistant, and examples of the conductive assistant may include nickel powder, cobalt oxide, titanium oxide, and carbon. As carbon, Ketjen black, acetylene black, furnace black, graphite, carbon fiber, fullerene, etc. can be illustrated.

The lithium secondary battery of the present invention includes the negative electrode. The lithium secondary battery includes a negative electrode, a positive electrode, and an electrolyte, and may include a separator as necessary.

As a positive electrode of the said lithium secondary battery, if it is a positive electrode normally used in a lithium secondary battery, it can be used, The thing shape | molded in paste form, flat shape, etc. by mixing a binder and a conductive support material with positive electrode active material powder is mentioned.

As a cathode active material is, for example, such as _{LiMn 2 O 4, LiCoO 2,} LiNiO 2, LiFeO 2, V 2 O 5 is preferred. Moreover, it is good to use what can occlude and desorb lithium, such as TiS, MoS, an organic disulfide compound, or an organic polysulfide compound. As the conductive assistant, conductive crude such as ketjen black, acetylene black, furnace black, graphite, carbon fiber, and fullerene is preferable. In addition, the binder includes polyvinylidene fluoride, carboxymethyl cellulose, methyl cellulose, sodium polyacrylate, and the like.

The positive electrode is formed by applying a slurry obtained by mixing a positive electrode active material powder, a binder, and a conductive aid to a metal current collector, drying, and rolling.

Any separator may be used as long as it is used in a lithium secondary battery, and examples thereof include polyethylene, polypropylene, or a multilayer film thereof, polyvinylidene fluoride, polyamide, glass fiber, and the like.

As electrolyte of a lithium secondary battery, the organic electrolyte solution which melt | dissolved lithium salt in the non-aqueous solvent is mentioned, for example.

As the non-aqueous solvent, propylene carbonate, ethylene carbonate, butylene carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, -butyrolactone, dioxolane, 4-methyldioxolane, N, N -Dimethylformamide, dimethylacetoamide, dimethyl sulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl propyl carbonate , Non-aqueous solvents such as methyl isopropyl carbonate, ethyl butyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, diethylene glycol, dimethyl ether, or a mixed solvent in which two or more of these solvents are mixed, and also lithium Examples of conventionally known solvents for secondary batteries include those known as propylene carbonate, Is a mixture of one of the alkylene carbonate, butyl dimethyl carbonate as containing one of carbonate, methyl ethyl carbonate, diethyl carbonate, is preferred.

Lithium salts include LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiClO ₄ , LiAlO ₄ , LiAlCl ₄ , LiN (C _x F _{2x + 1} SO ₂ ) (C _y F _{2y + 1} SO ₂ ) (where x and y are natural numbers), LiCl and LiI, or You can use more than one.

Further examples of the electrolyte include polymers such as polyethylene oxide, polypropylene oxide, polyacetonitrile, polyvinylidene fluoride, polymethacrylate, polymethylmethacrylate, etc., which have excellent swelling properties with respect to the organic electrolyte and the organic electrolyte. Examples thereof include polymer electrolytes containing this polymer.

The lithium secondary battery of the present invention is manufactured by encapsulating the negative electrode, the positive electrode, the electrolyte, and the separator as necessary in a battery case. 1 is a perspective view of a lithium secondary battery 1 which is one embodiment of the present invention. The lithium secondary battery 1 is cylindrical and has a negative electrode 2, a positive electrode 3, a separator 4 disposed between the negative electrode 2 and the positive electrode 3, a negative electrode 2, a positive electrode 3, and The main part consists of the sealing member 6 which encloses the electrolyte, the cylindrical battery container 5, and the battery container 5 impregnated with the separator 4 as a main part. The lithium secondary battery 1 is configured by stacking the negative electrode 2, the positive electrode 3, and the separator 4 in order, and then storing the lithium secondary battery 1 in the battery container 5 in a state of being wound in a spiral shape.

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following examples are only one preferred embodiment of the present invention and the present invention is not limited to the following examples.

(Example 1)

Plate-like graphite powder with an average particle diameter of 30 µm was It was put into a pin mill and ground first. In this process, the parent portions and protrusions of the plate graphite powder were removed to be spherical or pseudo-spherical to form a primary assembly of plate graphite. Primary granulated platelet graphite was introduced into mechanofusion and then pulverized second. At this time, the plate-like graphite was prepared by laminating the carbon material in which the fine graphite particles were second-assembled on the surface of the plate-like graphite which is aligned in the plane direction and laminated in this plane orientation.

92 parts by weight of the carbon material as the negative electrode active material and 8 parts by weight of polyvinylidene fluoride as the binder resin were added to N-methylpyrrolidone and dispersed to prepare a slurry for the negative electrode, which was applied to a copper current collector. It was then rolled into a roll press to produce a cathode having a pole plate density of 1.5, 1.65, 1.85 and 2.0 g / cc.

A coin type half cell was manufactured using the negative electrode and the lithium metal as counter electrodes. In this case, a mixed solution of ethylene carbonate / dimethyl carbonate and ethylmethyl carbonate (3/3/4 volume ratio) in which 1.0 M LiPF ₆ was dissolved was used.

(Example 2)

A battery was manufactured in the same manner as in Example 1, except that 10 parts by weight of mesophase pitch was added to 100 parts by weight of the first assembly in order to perform a second assembly process.

(Comparative Example 1)

The silica particles were mixed with natural graphite particles, pitches and graphitization catalysts having an average particle size of 15 μm, and then molded and pulverized. The granulated amorphous particles were carbonized and subjected to high temperature graphitization to obtain a graphitized granulated powder, which was used as a negative electrode active material. A battery was manufactured in the same manner as in Example 1.

(Comparative Example 2)

The cell was prepared in the same manner as in Example 1 except that the amorphous particles obtained by mixing and grinding silica with primary carbonized coke particles, pitch and graphitization catalyst were carbonized and subjected to high temperature graphitization to be used as a negative electrode active material. Prepared.

(Comparative Example 3)

The same procedure as in Example 1 was carried out except that amorphous artificial graphite was used as the negative electrode active material.

The compressive strengths of the negative electrode active materials of Examples 1 and 2 and Comparative Examples 1 to 3 were measured and described in Table 1 below. The compressive strength was determined by pressing the powder in one layer, applying a constant pressure from above, and then breaking the material at a certain moment, and determining the compressive strength until then.

In addition, the batteries of Examples 1 and 2 and Comparative Examples 1 to 3 were charged and discharged by 0.2C under CC / CV conditions. The initial discharge capacity and the charge / discharge efficiency according to the electrode plate density were measured and listed in Table 1 below.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Compressive strength (MPa) of active material particles 30 35 7 12 12 Initial discharge capacity according to pole plate density (charge and discharge efficiency) 1.8 g / cc 350 mAh / g (92%) 352 mAh / g (94%) 340 mAh / g (92%) 346 mAh / g (92%) 330 mAh / g (92%) 2.0 g / cc 340 mAh / g (91%) 348 mAh / g (91%) 310 mAh / g (84%) 324 mAh / g (88%) 315 mAh / g (90%)

As shown in Table 1, it can be seen that the active materials of Examples 1 and 2 are significantly superior to Comparative Examples 1 to 3 in the active material compressive strength. Accordingly, the active materials of Examples 1 and 2 can secure a sufficient penetration path of the electrolyte solution in the electrode plate during the production of the high density electrode plate. This can be confirmed from the comparison of the discharge capacity of the battery to which the high-density electrode plate of 1.8 g / cc or more is compared with the initial discharge capacity and efficiency of Examples 1 and 2 according to the present invention as compared with Comparative Examples 1 to 3.

The negative electrode active material of the present invention has a high density, excellent compressive strength of particles, can provide a high-density electrode plate, it is possible to increase the capacity of the battery.

Claims (31)

First carbon powder particles having a form in which the plate-shaped particles are aligned and stacked in a plane direction and primaryly assembled; And A negative active material for a lithium secondary battery having a structure in which second fine carbon powder particles are secondary granulated on a surface of the carbon powder particles and having a particle compressive strength of 15 to 45 Mpa.  The negative active material of claim 1, wherein the active material particles contain 30% to 100% of a carbon powder having a particle compressive strength of 15 to 45 Mpa.  The negative active material of claim 1, wherein the active material particles contain one or two or more kinds of carbon powder having a particle compressive strength of 15 to 45 Mpa. The negative active material of claim 1, wherein the first carbon powder particles are spherical or pseudo-spherical natural graphite or artificial graphite having a particle diameter of 10 to 25 μm. The negative active material of claim 1, wherein the first carbon powder particles have an intensity ratio between the (110) plane and the (002) plane by an X-ray diffraction analysis of 0.002 to 0.2 or less. The negative active material of claim 1, wherein the second fine carbon powder particles are fine graphite particles having an average length or particle diameter of 0.5 to 5 μm. The negative active material of claim 1, wherein an amorphous carbon coating layer is further present on the surface of the first carbon powder particles in addition to the second fine carbon powder particles. The negative active material of claim 1, wherein the negative active material has a long / short ratio of 1 to 4 particles. The negative active material of claim 1, wherein the negative active material has a fine porosity of 10% to 40% by a pore of 0.5 μm or less. The negative active material of claim 9, wherein the negative active material has a porosity of 15 to 35% occupied by pores of 0.5 μm or less. The negative active material of claim 1, wherein the negative active material has a fine porosity of 3 to 12% occupied by pores of 0.1 μm or less. The negative active material of claim 1, wherein the negative active material has a fine porosity of 3 to 10% occupied by pores of 0.1 μm or less. The negative electrode active material of claim 1, wherein the fine porosity of the negative electrode active material is 1.1 to 2.0 times the fine porosity of the electrode plate. The negative active material of claim 1, wherein the negative active material is a carbon material having a tap density of 1.0 g / cc to 1.30 g / cc and an apparent density of 0.6 to 1.0 g / cc. delete The negative electrode active material of claim 1, wherein a specific surface area of the negative electrode active material measured by a BET method is 2.0 to 4.0 m ³ / g. The carbon material is spheroidized or pseudo-spherized at the same time through mechanical mechanical grinding, Secondary granulation of fine carbon powder particles produced during the spheroidization or pseudospherization process on the surface of the plate-like carbon material using a crusher that imparts interfacial friction and shear force, A method of manufacturing the negative electrode active material for a lithium secondary battery according to claim 1, comprising the step of heat treating the assembly. The method of claim 17, further comprising adding an amorphous carbon precursor in the secondary granulation step. The method of claim 18, wherein the amorphous carbon precursor is added in an amount of 5 to 30 parts by weight based on 100 parts by weight of the plate-shaped carbon material. First carbon powder particles having a form in which the plate-shaped particles are aligned and stacked in a plane direction and primaryly assembled; And The negative electrode for a lithium secondary battery having a pole plate density of 1.5g / cc to 2.0g / cc containing a negative electrode active material having a structure in which the second fine carbon powder particles are secondary granulated on the surface of the carbon powder particles. The negative electrode for a rechargeable lithium battery of claim 20, wherein the first carbon powder particles are spherical or pseudo-spherical natural graphite or artificial graphite having a particle diameter of 10 to 25 μm. The negative electrode of claim 20, wherein the first carbon powder particles have an intensity ratio between (110) and (002) planes of 0.002 to 0.2 by X-ray diffraction analysis. The negative electrode for a rechargeable lithium battery of claim 20, wherein the second fine carbon powder particles are fine graphite particles having an average length or particle diameter of 0.5 to 5 μm. The negative electrode for a lithium secondary battery of claim 20, further comprising an amorphous carbon coating layer on the surface of the first carbon powder particles in addition to the second fine carbon powder particles. The negative electrode for a rechargeable lithium battery of claim 20, wherein the negative active material has a ratio of the major axis to the minor axis of 1 to 4. The negative electrode of claim 20, wherein the negative electrode active material has a fine porosity of 10% to 40% by pores of 0.5 μm or less. The negative electrode for a lithium secondary battery according to claim 20, wherein the fine porosity of the negative electrode active material is 1.1 to 2.0 times the fine porosity of the electrode plate. The negative electrode of claim 20, wherein the negative active material is a carbon material having a tap density of 1.0 to 1.3 g / cc and an apparent density of 0.6 to 1.0 g / cc. delete The negative electrode for a rechargeable lithium battery of claim 20, wherein a specific surface area of the negative electrode active material measured by a BET method is 2.0 to 4.0 m ³ / g. A positive electrode including a positive electrode active material; A cathode according to any one of claims 20 to 28 and 30; And Electrolyte Containing Lithium Salt and Non-Aqueous Solvent Lithium secondary battery comprising a.

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