KR20110138606A - Negative electrode with improved wetting property to electrolyte and secondary battery comprising the same - Google Patents

Abstract

PURPOSE: A negative electrode is provided to improve electrolyte wettability by using amorphous carbon material. CONSTITUTION: A negative electrode comprises negative electrode mixture, containing a negative electrode active material including amorphous carbon material and doping atoms, a binder, and a conductive material, formed on a current collector. The density of electrode is 0.9g/cc-2.00g/cc. The absorbing time of non-aqueous electrolyte including lithium salt and organic solvent, is 50-380 second per the 1μl of the non-aqueous electrolyte.

Description

Anode for secondary batteries having excellent electrolyte impregnation and a secondary battery comprising the same {NEGATIVE ELECTRODE WITH IMPROVED WETTING PROPERTY TO ELECTROLYTE AND SECONDARY BATTERY COMPRISING THE SAME}

A negative electrode for a secondary battery having excellent electrolyte solution impregnation and a secondary battery including the same are provided. More specifically, by including the negative electrode and the reduced resistance generated at the interface between the electrolyte and the electrode active material and the electrode, there is provided a secondary battery excellent in charge and discharge characteristics and life characteristics.

With the development of portable electronic devices such as mobile phones and notebook computers, the demand for secondary batteries as a source of energy is rapidly increasing. In addition, in order to reduce problems caused by global warming and the use of fossil fuels, hybrid electric vehicles (HEVs) and electric motors driven by electric motors (EVs) have been developed, and the use of secondary batteries as a power source thereof has been realized. It is becoming. Accordingly, many studies have been conducted on secondary batteries capable of meeting various demands, and in particular, there is a growing demand for lithium secondary batteries having high energy density, high discharge voltage and output.

Lithium secondary batteries used in electric vehicles should have high energy density and high output characteristics in a short time, and should be able to be used for more than 10 years under severe conditions where charging and discharging by a large current is repeated in a short time. The output characteristics and long lifespan characteristics which are much better than a lithium secondary battery are inevitably required. In addition, a lithium secondary battery used in an electric vehicle or the like may generate a rapid exothermic reaction, and in particular, a sudden exothermic reaction should be prevented for safety.

The lithium secondary battery has a structure in which a non-aqueous electrolyte containing lithium salt is impregnated in an electrode assembly having a porous separator interposed between a positive electrode and a negative electrode on which an active material is coated on a current collector. The positive electrode active material is mainly composed of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium composite oxide and the like, and the negative electrode active material is mainly composed of a carbon-based material.

Carbonaceous materials are composed of soft carbon having a layered crystal structure that is easily graphitized, hard carbon that is difficult to graphitize, and a layered crystal structure such as natural graphite. Classify as graphite.

In particular, the anode made of graphite-based material, which is a layered crystal mainly used as a cathode active material, has a theoretical maximum capacity of 372 mAh / g and has a limited capacity increase, making it difficult to play a sufficient role as an energy source for a rapidly changing next-generation mobile device. to be.

On the other hand, the recent research direction of a battery using a non-aqueous electrolyte such as a lithium secondary battery has been made in the direction of high capacity and high output. On the other hand, due to the characteristics of the non-aqueous electrolyte battery, ion mobility in the electrolyte is poor, and in many cases, impregnation of the electrolyte solution is not performed quickly. Therefore, in the non-aqueous electrolyte battery, the electrolyte solution needs to be sufficiently impregnated with the electrode within a short time.

When the impregnation of the electrolyte solution is lowered, the electrolyte solution does not reach the active material particles of the electrode, so that lithium ions are not moved smoothly, and there is a concern that the current may be reduced accordingly. In addition, when the impregnation rate of the electrolyte drops, the productivity of the lithium secondary battery decreases. Furthermore, in order to maintain a comprehensive balance of battery characteristics, it is necessary to improve electrolyte solution impregnation in the non-aqueous electrolyte battery.

According to one embodiment of the present invention, a negative electrode for a secondary battery excellent in electrolyte impregnation, a negative electrode mixture comprising an amorphous carbon material and a doping element, a negative electrode mixture comprising a binder and a conductive material is formed on the current collector, Provided is a negative electrode for a secondary battery having an electrode density of 0.9 g / cc to 2.00 g / cc and an absorption time of a non-aqueous electrolyte containing a lithium salt and a carbonate organic solvent between 50 and 380 seconds per 1 µl of the non-aqueous electrolyte. do.

The negative electrode according to an embodiment of the present invention is a negative electrode mixture including an anode active material including an amorphous carbon material and a doping element, a binder and a conductive material is formed on the current collector, the electrode density is 0.9 g / cc to 2.00 g / cc, and the absorption time for the non-aqueous electrolyte containing a lithium salt and a carbonate-based organic solvent is a negative electrode for a secondary battery having between 50 and 380 seconds per 1 µl of the non-aqueous electrolyte.

A secondary battery according to an embodiment of the present invention is a secondary battery including the negative electrode.

The method of manufacturing a negative electrode according to an embodiment of the present invention is at least one raw material precursor selected from the group consisting of petroleum coke, coal coke, coal-based pitch, petroleum-based pitch, mesophase pitch, mesocarbon microbeads and vinyl chloride-based resin And uniformly mixing a doping element under a solvent, drying, calcining, and carbonizing the mixed mixture, and pulverizing a carbide having undergone the drying, calcining, and carbonization. Manufacturing step; Preparing a slurry by adding a negative electrode mixture including the negative electrode active material and a binder to a predetermined solvent; Applying the slurry to a current collector; It is a method of manufacturing a negative electrode for a secondary battery comprising the step of drying and rolling the current collector is coated with the slurry.

A secondary battery negative electrode having a small interfacial resistance between an electrolyte solution and an active material and excellent in impregnation with an electrolyte solution, which can easily maintain a comprehensive balance of battery characteristics and increase productivity of the secondary battery, and a secondary battery including the same. A battery is provided.

1 is a graph showing the impregnation time of the electrolyte according to the electrode density of the negative electrode according to the embodiment of the present invention and the negative electrode according to the comparative example.

Hereinafter, the Example of this invention is described concretely.

The negative electrode for a secondary battery according to the present invention is a negative electrode having a negative electrode active material containing an amorphous carbon material and a doping element, a binder and a conductive material formed on the current collector, the electrode density is 0.9 g / cc to 2.00 g / cc, and the absorption time for the non-aqueous electrolyte containing a lithium salt and a carbonate organic solvent is composed of 50 to 380 seconds per 1 μl of the non-aqueous electrolyte.

The absorption time means a time from when 1 µl of the non-aqueous electrolyte is dropped to contact the surface of the negative electrode until it is completely lost from the surface of the negative electrode.

The secondary battery negative electrode according to the present invention has an electrode density between 0.9 g / cc and 2.00 g / cc and a fast electrolyte absorption time of 50 to 380 seconds per 1 μl of the non-aqueous electrolyte, thereby providing high affinity and impregnation for the electrolyte. It is easy to maintain the overall balance of battery characteristics during the manufacture of the secondary battery, and in the vacuum injection method applied in the mass production process, the productivity of the secondary battery can be increased by shortening the electrolyte impregnation time larger than the above effect. .

In particular, the negative electrode is at least one lithium salt selected from the group consisting of LiPF ₆ , LiClO ₄ , LiBF ₄ , LiAsF ₆ and ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate ( Carbonate-based organic solvents including diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) and demethoxy ethane (DME), lactone ( The absorption rate of the non-aqueous electrolyte solution containing at least one organic solvent selected from the group consisting of Lactone (v-BL)) and tetrahydrofuran (THF) is very excellent.

The electrode density of the anode for the secondary battery is not particularly limited as long as it is between 0.9 g / cc and 2.00 g / cc so as to exhibit high affinity and impregnation for the electrolyte, and more preferably, the electrode density is 1.1 g / cc. To 1.27 g / cc may be used.

In addition, the electrolyte absorption time of the negative electrode for secondary batteries is preferably 50 to 380 seconds per 1 μl of the non-aqueous electrolyte, and more preferably 100 to 280 seconds per 1 μl of the non-aqueous electrolyte.

The anode active material includes an amorphous carbon material having excellent fast charging characteristics and cycle characteristics.

The amorphous carbon material may be any of a digraphitizable carbon material (soft carbon) and a nongraphitizable carbon material (hard carbon), but it is preferable to use a digraphitizable carbon material. The digraphitizable carbon material can be obtained by heat treating the raw material precursor under air or an inert gas atmosphere and under a predetermined temperature condition to partially graphitize the raw material precursor. Grinding and / or crushing processes may be introduced as necessary during this process. For example, the negative electrode active material may include grinding the raw material precursor into a powder form; And it may be prepared through the step of heating the ground raw material precursor at 500 to 2500 ℃.

The milling and / or crushing may be performed by a ball mill, an attention mill, a vibration mill, a disk mill, a jet mill, a rotor mill, or the like. It can be carried out by milling the raw material precursor using the same mill. The milling may be a dry process, or a wet process, or a combination of dry and wet. In the grinding and / or crushing process, the average particle diameter and particle size distribution of the particles may be controlled by the grinding speed, pressure, time, and the like. Therefore, the average particle diameter and particle size distribution of the negative electrode active material may be determined by the grinding and / or crushing process.

The digraphitizable carbon material has a regular arrangement of hexagonal crystals (hexagonal network structure arrangement) after the raw material precursor has been graphitized.

Although it does not specifically limit as a raw material precursor of the said digraphitizable carbon material, For example, petroleum coke, coal coke, coal pitch, petroleum pitch, mesophase pitch, mesocarbon microbeads, vinyl chloride type resin, etc. are independent. Or combinations of two or more thereof.

The doping element is not particularly limited as long as it does not cause chemical change in the secondary battery, and includes, for example, manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), and zinc (Zn). Group 3 containing a transition metal compound, boron (B), aluminum (Al), gallium (Ga), indium (In), nitrogen (N), silicon (Si), phosphorus (P), arsenic (As), One or more elements selected from the group consisting of Group 4 and Group 5 element compounds, sodium (Na) potassium (Ka) magnesium (Mg) and calcium (Ca) alkali metal compounds or alkaline earth metal compounds can be used.

As the transition metal compound containing nickel (Ni), one or more selected from the group consisting of nickel nitrate, nickel sulfate, nickel acetate, and the like may be used. Examples of the compound containing boron (B) include borate and boron. Acid, boron oxide, boron sulfide, boron nitride, boron chloride, etc. may be used one or more selected from the group consisting of phosphorus (P) as a compound containing hydrogen phosphide, phosphorus pentoxide, phosphoric acid, superphosphate, oxo At least one selected from the group consisting of acids and the like can be used.

The content of the doping element may be appropriately adjusted to improve the electrical conductivity and high temperature safety in consideration of the type of the negative electrode active material, and may preferably be included in an amount of 0.1 to 20% by weight based on the total weight of the negative electrode active material. If the content of the doping element is too small it is difficult to exert the effect of the addition, on the contrary too much is not preferable because the ratio of the doping element contained in the negative electrode active material may increase the battery characteristics can be reduced.

The binder is a component that assists the bonding between the negative electrode active material and the conductive material and the current collector, and is generally added in an amount of 1 to 50 wt% based on the total weight of the mixture including the positive electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluorine rubber, various copolymers, and the like.

The conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, carbon black, acetylene black, thermal black, channel black conductive fibers such as carbons such as channel black, furnace black, graphite, and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder and nickel powder; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The negative electrode mixture may optionally include a filler, an adhesion promoter, and the like.

The filler is an auxiliary component that suppresses the expansion of the electrode, and is not particularly limited as long as it is a fibrous material without causing chemical changes in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The adhesion promoter is an auxiliary component added to improve adhesion of the active material to the current collector, and may be added in an amount of 10 wt% or less, for example, oxalic acid, adipic acid, Formic acid, acrylic acid derivatives, itaconic acid derivatives, and the like.

In addition, the negative electrode on which the negative electrode mixture is applied on the current collector, for example, may be prepared by coating the negative electrode mixture on the current collector. Specifically, the negative electrode mixture may be added to a predetermined solvent to prepare a slurry, and then, the slurry mixture may be coated on a current collector such as a metal foil, dried, and rolled to prepare a predetermined sheet-shaped electrode.

Secondary battery according to an embodiment of the present invention is composed of a secondary battery including the negative electrode.

Generally, the negative electrode is prepared by adding a negative electrode mixture to a solvent such as NMP to prepare a slurry, and then applying the same to a current collector to dry and press. Preferred examples of the solvent used in the preparation of the slurry include dimethyl sulfoxide (DMSO), alcohol, N-methylpyrrolidone (NMP), sodium carboxymethylcellulose (CMC, sodium carbonxymethylcellulose), acetone, and the like. The solvent may be used up to 400% by weight based on the total weight of the negative electrode mixture, and is removed in the drying process.

The negative electrode current collector is generally made to have a thickness of 3 to 500 mu m. Such a negative electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, the surface of copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver, and the like, aluminum-cadmium alloy, and the like can be used. In addition, like the positive electrode current collector, fine concavities and convexities may be formed on the surface to enhance the bonding strength of the negative electrode active material, and may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric.

The method of evenly applying the negative electrode mixture paste on the negative electrode current collector may be selected from known methods or performed by a new suitable method in consideration of the properties of the material. For example, after dispensing the paste onto the current collector, it is preferable to disperse the paste uniformly using a doctor blade or the like. In some cases, a method of performing the distribution and dispersion processes in one process may be used. In addition, a method such as die casting, comma coating, screen printing, or the like may be selected, or may be molded on a separate substrate and then bonded to the current collector by pressing or lamination. Drying of the paste applied on the current collector is preferably dried for 12 to 72 hours in a vacuum oven at 50 ℃ to 200 ℃.

The secondary battery may preferably be a lithium secondary battery containing a lithium salt-containing nonaqueous electrolyte. The lithium secondary battery may be manufactured in a structure in which a lithium salt-containing non-aqueous electrolyte is impregnated into an electrode assembly having a separator interposed between the negative electrode and the positive electrode.

Other components of the lithium secondary battery according to the present invention will be described in detail below.

The positive electrode is prepared by, for example, applying a mixture of a positive electrode active material, a conductive material, and a binder to a positive electrode current collector, followed by drying, and optionally, a filler is further added to the mixture.

The positive electrode current collector is generally made to a thickness of 3 to 500 ㎛. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, a surface of stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel Surface treated with carbon, nickel, titanium, silver or the like can be used. The current collector may form fine irregularities on its surface to increase the adhesion of the positive electrode active material, and may be in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Li _{1 + y} Mn _{2 - y} O ₄ (Where y is 0 to 0.33), lithium manganese oxide such as LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ ; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ , Cu ₂ V ₂ O ₇ and the like; Ni-site type lithium nickel oxide represented by the formula LiNi _{1 - y} M _y O ₂ (wherein M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and y = 0.01 to 0.3); Formula LiMn _{2 - y} M _y O ₂ (wherein M = Co, Ni, Fe, Cr, Zn or Ta and y = 0.01 to 0.1) or Li ₂ Mn ₃ MO ₈ (wherein M = Fe, Co, Lithium manganese composite oxide represented by Ni, Cu or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with alkaline earth metal ions; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ and the like can be used, but are not limited thereto.

The separator is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally from 0.01 to 10 ㎛ ㎛, thickness is generally 5 ~ 300 ㎛. As such a separator, for example, olefin polymers such as chemical resistance and hydrophobic polypropylene; Sheets or non-woven fabrics made of glass fibers or polyethylene are used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

The lithium salt-containing nonaqueous electrolyte solution is composed of an electrolyte solution and a lithium salt. As the electrolyte solution, a nonaqueous organic solvent, an organic solid electrolyte, and an inorganic solid electrolyte may be used.

Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and gamma Butyl lactone, 1,2-dimethoxy ethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxorone, formamide, dimethylformamide, dioxolon , Acetonitrile, sodium carboxymethylcellulose, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxy methane, dioxoron derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazoli Aprotic organic solvents such as dinon, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl pyroionate and ethyl propionate can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, Polymers containing ionic dissociation groups, and the like can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides, sulfates and the like of Li, such as Li ₄ SiO ₄ -LiI-LiOH, Li ₃ PO ₄ -Li ₂ S-SiS ₂ , and the like, may be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

In addition, in the electrolyte solution, for the purpose of improving the charge and discharge characteristics, flame retardancy, etc., for example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, hexaphosphate triamide, nitro Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxy ethanol, aluminum trichloride and the like may be added. . In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability, or a carbon dioxide gas may be further added to improve high-temperature storage characteristics.

At least one selected from the group consisting of petroleum coke, coal coke, coal-based pitch, petroleum-based pitch, mesophase pitch, mesocarbon microbeads and vinyl chloride-based resin according to an embodiment of the present invention The negative electrode by a method comprising uniformly mixing the raw material precursor and the doping element under a solvent, drying, calcining and carbonizing the mixed mixture, and pulverizing carbide after the drying, calcining and carbonization Preparing an active material; Preparing a slurry by adding a negative electrode mixture including the negative electrode active material and a binder to a predetermined solvent; Applying the slurry to a current collector; It comprises the step of drying and rolling the current collector to which the slurry is applied.

The firing and carbonization process may be performed in a vacuum or inert atmosphere, for example, in a nitrogen or argon atmosphere to prevent oxidation of the raw precursor material.

The firing process may be carried out at a temperature higher than the carbonization temperature of the precursor material, may also vary depending on the type of precursor material used, for example, may be performed at a temperature of 600 ℃ to 2000 ℃.

In the pulverizing process, it is preferable to pulverize the carbide which has been subjected to the calcination and carbonization to an average particle size of about 3 μm to 30 μm, and the pulverization may be performed by using the above-mentioned grinding method of the digraphitizable carbon material. Can be performed.

If the average particle diameter of the pulverized carbide is too large, there is a problem that the bulk density of the negative electrode active material is lowered. On the contrary, if the average particle diameter is too small, the irreversible capacity of the negative electrode material is high, and it is difficult to expect a desired discharge capacity. Not.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the technical spirit of the present invention is not limited or limited thereto.

[ Example ]

Example  One

Petroleum coke was used as an amorphous carbon raw material, and the petroleum coke was 500? The total weight ratio of 6 wt% of phosphoric acid was dispersed in the amorphous carbon precursor obtained by heat treatment and grinding at the above temperature for 10 minutes. This was heat-treated at a temperature of 800 ° C. or more within 2 hours to prepare a carbonaceous active material. A negative electrode mixture containing the carbonaceous active material, acrylonitrile butadiene rubber as a binder, and Super-P (manufactured by Timcal) as a conductive material was added to water and an ethanol solvent to prepare a slurry, and then to a copper foil as a current collector. After application, the slurry was applied to the current collector was dried to prepare a negative electrode, and the electrode density was pressed at 1.21 g / cc and then included 1M LiPF ₆ lithium salt and ethylene carbonate / ethyl methyl carbonate (EC / EMC) solvent The impregnation time for the non-aqueous electrolyte was measured.

Example  2

An electrode was prepared in the same manner as in Example 1 except that the electrode density was pressed at 1.22 g / cc, and the electrolyte solution impregnation time was measured.

Example  3

An electrode was prepared in the same manner as in Example 1 except that the electrode density was pressed at 1.24 g / cc, and the electrolyte solution impregnation time was measured.

Example  4

An electrode was prepared in the same manner as in Example 1 except that the electrode density was pressed at 1.25 g / cc, and the electrolyte solution impregnation time was measured.

Comparative example  One

Petroleum-based coke was used as an amorphous carbon raw material, and the amorphous carbon obtained by heat-treating and pulverizing the petroleum coke at a temperature of 500 ° C. or higher was heat-treated at a temperature of 800 ° C. or higher for 2 hours to prepare a carbonaceous active material. A negative electrode mixture including the carbonaceous active material, acrylonitrile butadiene rubber as a binder, and Super-P (manufactured by Timcal) as a conductive material was added to water and an ethanol solvent to prepare a slurry, and then to a copper foil as a current collector. After application, the slurry was applied to the current collector was dried to prepare a negative electrode, and the electrode density was pressed at 1.22 g / cc and then included 1M LiPF ₆ lithium salt and ethylene carbonate / ethyl methyl carbonate (EC / EMC) solvent The impregnation time for the non-aqueous electrolyte was measured.

Comparative example  2

An electrode was prepared in the same manner as in Example 1 except that the electrode density was pressed at 1.23 g / cc, and the electrolyte solution impregnation time was measured.

Comparative example  3

An electrode was prepared in the same manner as in Example 1 except that the electrode density was pressed at 1.24 g / cc, and the electrolyte solution impregnation time was measured.

Comparative example  4

An electrode was prepared in the same manner as in Example 1 except that the electrode density was pressed at 1.25 g / cc, and the electrolyte solution impregnation time was measured.

Table 1 and Figure 1 shows the contents of the electrolyte solution impregnation time according to the electrode density of the above experimental examples and comparative examples.

Electrode Density (g / cc) Impregnation time (sec) Comparative Example 1 1.22 404 Comparative Example 2 1.23 424 Comparative Example 3 1.24 479 Comparative Example 4 1.25 488 Example 1 1.21 160 Example 2 1.22 205 Example 3 1.24 214 Example 4 1.25 256

As can be seen in Table 1 it can be seen that the negative electrode according to the embodiment of the present invention has a faster impregnation time for the non-aqueous electrolyte than the negative electrode of the comparative example. Through the results confirmed by improving the affinity between the electrolyte solution of the active material it can be seen that the negative electrode according to the embodiment of the present invention can improve the battery characteristics by improving the impregnation of the electrolyte of the lithium secondary battery.

As described above, the present invention has been described by way of a limited embodiment, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains may make various modifications and variations from this description. Do.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

◆: Comparative Example 1
■: Comparative Example 2
*: Example 1
●: Example 2

Claims (12)

An anode having a negative electrode active material including an amorphous carbon material and a doping element, a binder and a conductive material formed on a current collector, having an electrode density of 0.9 g / cc to 2.00 g / cc, lithium salt and organic A negative electrode for a secondary battery having an absorption time for a non-aqueous electrolyte solution containing a solvent is between 50 and 380 seconds per 1 μl of the non-aqueous electrolyte solution. The method of claim 1,
The lithium salt is a lithium secondary battery, characterized in that at least one selected from the group consisting of LiPF ₆ , LiClO ₄ , LiBF ₄ and LiAsF ₆ . The method of claim 1,
The organic solvent is organic ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethylmethyl carbonate. (Ethyl methyl carbonate (EMC)) is a negative electrode for a secondary battery, characterized in that at least one carbonate organic solvent selected from the group consisting of. The method of claim 1,
The electrode density of the secondary battery negative electrode, characterized in that 1.1 g / cc to 1.27 g / cc. The method of claim 1,
The absorption time is a negative electrode for secondary batteries, characterized in that between 100 to 280 seconds per 1 μl of the non-aqueous electrolyte. The method of claim 1,
The amorphous carbon material is a secondary battery negative electrode, characterized in that the graphite graphite material. The method of claim 6,
Raw material precursor of the graphitizable carbon material is at least one selected from the group consisting of petroleum coke, coal coke, coal-based pitch, petroleum-based pitch, mesophase pitch, mesocarbon microbeads and vinyl chloride-based resin cathode. The method of claim 1,
The doping element is a transition metal compound including manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), boron (B), aluminum (Al), gallium (Ga), Group 3, 4 and 5 elemental compounds including indium (In), nitrogen (N), silicon (Si), phosphorus (P) and arsenic (As), sodium (Na) potassium (Ka) magnesium (Mg) An anode for secondary batteries, characterized in that at least one selected from the group consisting of alkali metal compounds or alkaline earth metal compounds containing calcium (Ca). The method of claim 1,
The content of the doping element is a secondary battery negative electrode, characterized in that 0.1 to 20% by weight based on the total weight of the negative electrode active material. A secondary battery comprising the negative electrode according to any one of claims 1 to 9. The secondary battery of claim 10, wherein the secondary battery is a lithium secondary battery. Uniformly mixing at least one raw material precursor and a doping element selected from the group consisting of petroleum coke, coal coke, coal-based pitch, petroleum-based pitch, mesophase pitch, mesocarbon microbeads and vinyl chloride-based resins under a solvent, the Preparing a negative electrode active material by a method comprising the steps of drying, firing, and carbonizing the mixed mixture, and pulverizing a carbide having undergone the drying, firing, and carbonization;
Preparing a slurry by adding a negative electrode mixture including the negative electrode active material and a binder to a predetermined solvent;
Applying the slurry to a current collector;
Method of manufacturing a negative electrode for a secondary battery comprising the step of drying and rolling the current collector, the slurry is applied.

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