KR20130117355A - Electrodes for secondary battery and lithium secondary battery containing the same - Google Patents

Abstract

PURPOSE: An electrode for a secondary battery has excellent adhesive strength between electrode active materials or between the electrode active material and current collector with small amount of binder, thereby improving the performance of the secondary battery. CONSTITUTION: An electrode for a secondary battery in which an electrode mixture comprising an electrode active material, a binder, and an electric conductor is coated on the current collector. On the basis of the solid content of the electrode mixture, 0.1-15 weight% of the binder is included. The electrode mixture has a loading volume of 0.1-5 mAh/cm2. The binder is selected from polyvinylidene fluoride, polyvinylalcohol, carboxymethyl cellulose, starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polyprophylene, ethylene-propylene-diene ether polymer, sulfonated EPDM, styrene butylene rubber, and fluorine rubber. [Reference numerals] (AA) Example 3; (BB) Example 5; (CC) Comparative example 1

Description

Electrode for Secondary Battery and Lithium Secondary Battery Comprising the Same {Electrodes for Secondary Battery and Lithium Secondary Battery Containing The Same}

The present invention relates to a secondary battery electrode and a lithium secondary battery comprising the same, and more particularly, a secondary battery electrode having an electrode mixture including an electrode active material, a binder, and a conductive material coated on a current collector, wherein the binder is an electrode. It is included in 0.1 to 15% by weight based on the solids content of the mixture, the electrode mixture relates to a secondary battery electrode and a lithium secondary battery comprising the same, characterized in that the loading amount of 0.1 to 5 mAh / cm ² .

The increase in the price of energy sources due to the depletion of fossil fuels, the increase of interest in environmental pollution, and the demand for environmentally friendly alternative energy sources are becoming indispensable factors for future life. Various researches on power generation technologies such as nuclear power, solar power, wind power, and tidal power have been continuing, and electric power storage devices for more efficient use of such generated energy have also been attracting much attention.

Particularly, in the case of a lithium secondary battery, the demand for an energy source is rapidly increasing due to an increase in technology development and demand for a mobile device. Recently, the use of a lithium secondary battery as a power source for an electric vehicle (EV) and a hybrid electric vehicle , And the area of use is also expanding for applications such as power assisted power supply through gridization.

Conventional lithium ion secondary batteries use a lithium cobalt composite oxide for the positive electrode and a graphite-based material for the negative electrode. However, in recent years, a spinel-structured lithium nickel-based metal oxide is used for the positive electrode. , Researches on using lithium titanium oxide or the like as a negative electrode active material have been much progressed.

The secondary battery has a problem in that the charge and discharge capacity decreases as the cycle progresses in the charging and discharging process while the lithium ion of the positive electrode is inserted into and detached from the negative electrode.

This phenomenon is the biggest cause of the separation of the electrode active material or between the electrode active material and the current collector due to the change of the volume of the electrode caused by the progress of the charging and discharging of the battery, so that the active material fails to function. In addition, during the insertion and desorption process, lithium ions inserted into the negative electrode do not escape properly, thereby reducing the active point of the negative electrode. As a result, the charge and discharge capacity and life characteristics of the battery may decrease as the cycle progresses.

In this regard, the binder provides adhesion between the electrode active materials and between the electrode active material and the current collector, and has an important effect on battery characteristics by suppressing volume expansion due to charging and discharging of the battery.

However, when a large amount of binder is used in the manufacturing process of the secondary battery in order to increase the adhesive force, the amount of the conductive material or the electrode active material is relatively decreased, so that the conductivity of the electrode is reduced or the battery capacity is reduced. There may be a problem that the process of applying the electrode is not easy to be diluted.

Therefore, there is a great need for a technology that can improve performance of a secondary battery by providing excellent adhesion between electrode active materials or between electrode active materials and a current collector while using an appropriate amount of binder.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

The inventors of the present application after extensive research and various experiments, the binder is contained in a predetermined amount based on the solid content of the electrode mixture, the electrode mixture is a current collector so that the loading amount of 0.1 to 5 mAh / cm ² When using the electrode for secondary batteries apply | coated to it, it was confirmed that the desired effect can be achieved and came to complete this invention.

Therefore, the present invention is an electrode for secondary batteries, the electrode mixture comprising an electrode active material, a binder and a conductive material is applied to the current collector, the binder is contained in 0.1 to 15% by weight based on the solids content of the electrode mixture, The electrode mixture provides a secondary battery electrode, characterized in that the loading amount of 0.1 to 5 mAh / cm ² .

In general, in order to manufacture an electrode for a secondary battery, a method of making an electrode active material, a conductive material, a binder, and the like into a slurry using an organic solvent, applying an electrode mixture in the form of a slurry to an electrode current collector, and drying and pressing is used.

Increasing the amount of the binder in the solid content in the slurry, there is an effect of increasing the adhesive force, there is a problem that the amount of the electrode active material and the conductive material is relatively reduced, the electrode density is reduced to reduce the loading amount and electrical conductivity of the electrode.

Thus, the inventors of the present invention confirmed that the electrode adhesive force and the electrical conductivity may exhibit an optimal value when the electrode for the secondary battery includes a predetermined amount of binder.

The binder is not limited as long as it is generally used in the art, and specifically, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, At least one selected from the group consisting of polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber and fluororubber.

Such a binder may be included in detail, 1 to 15% by weight, more specifically 5 to 13% by weight based on the solids content of the electrode mixture. The above range is for showing the electrode adhesion and electrical conductivity according to the optimum loading amount, if less than this can not achieve the desired level of adhesion and in many cases the adhesion can be increased but beyond the range of electrode adhesion applicable to the actual battery manufacturing However, since the amount of the electrode active material is relatively reduced, the physical properties of the battery may be lowered, which is not preferable.

In the present invention, the electrode may be an anode or a cathode, or an anode and a cathode.

The positive electrode may include a lithium metal oxide having a spinel structure represented by Chemical Formula 1 as a positive electrode active material.

Li _x M _y Mn _{2 - y} O _{4 - z z} (1)

In the above formula, 0.9 ≦ x ≦ 1.2, 0 <y <2, 0 ≦ z <0.2, and M is Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, At least one element selected from the group consisting of Nb, Mo, Sr, Sb, W, Ti and Bi; A is one or more of an anion of -1 or -2.

The lithium metal oxide may be represented by the following Chemical Formula 2 in more detail.

Li _x Ni _y Mn _2-y O ₄ (2)

Wherein 0.9 ≦ x ≦ 1.2, 0.4 ≦ y ≦ 0.5; More specifically, the lithium metal oxide may be LiNi _0.5 Mn _1.5 O ₄ or LiNi _0.4 Mn _1.6 O ₄ .

The negative electrode may include a lithium metal oxide represented by Chemical Formula 3 below.

Li _a M ' _b O _{4-ca c} (3)

In the above formula, M 'is at least one element selected from the group consisting of Ti, Sn, Cu, Pb, Sb, Zn, Fe, In, Al and Zr; a and b are 0.1? a? 4; Is determined according to the oxidation number of M 'in the range of 0.2? B? 4; c is determined according to the oxidation number in the range of 0? c <0.2; A is one or more of an anion of -1 or -2.

The lithium metal oxide may be represented by the following formula (4).

Li _a Ti _b O ₄ (4)

More specifically, the lithium metal oxide may be Li _1.33 Ti _1.67 O ₄ or LiTi ₂ O ₄ .

In particular, such lithium titanium oxide has a small particle size, a large specific surface area, and a uniform particle shape, and thus, a process of preparing an electrode mixture by mixing with a binder and a conductive material is not easy. It acts as a factor to lower the adhesion between the titanium oxide and the current collector. Accordingly, in the present invention, even when lithium titanium oxide is used as the negative electrode active material using a predetermined amount of binder, the optimum adhesion and electrical conductivity can be exhibited.

The present invention provides a secondary battery including the electrode.

Such a secondary battery includes an electrode prepared by applying a mixture of an electrode active material, a conductive material and a binder onto an electrode current collector, followed by drying and pressing, and in this case, a filler may be further added to the mixture as necessary.

The positive electrode current collector is generally made to a thickness of 3 to 500 mu m. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. Examples of the positive electrode current collector include stainless steel, aluminum, nickel, titanium, sintered carbon, aluminum or stainless steel A surface treated with carbon, nickel, titanium, silver or the like may be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

The positive electrode active material may be a material defined above, for example, further, 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; Lithium manganese oxides such as Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ and the like; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A Ni-site type lithium nickel oxide expressed by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ and the like can be used.

The conductive material is typically added in an amount of 1 to 50% by weight based on the total weight of the mixture including the positive electrode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, 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 filler is optionally used as a component for suppressing the expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change 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 negative electrode current collector is generally made to a thickness of 3 to 500 mu m. Such an anode current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and examples of the anode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, a surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

As the negative electrode active material, a material defined above may be used. For example, further, for example, carbon such as non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 &lt; x &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials can be used.

The lithium titanium oxide has a higher potential for lithium than graphite and excellent in safety because lithium reactants and lithium do not precipitate at the interface.

The secondary battery may have a structure in which a lithium salt-containing electrolyte is impregnated in an electrode assembly having a separator interposed between a positive electrode and a negative electrode.

The separation membrane 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 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The lithium salt-containing electrolyte solution is composed of an electrolyte solution and a lithium salt, water, non-aqueous organic solvent, organic solid electrolyte, inorganic solid electrolyte and the like are used, but are not limited to these.

Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like 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, A polymer containing an ionic dissociation group and the like may 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 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide.

For the purpose of improving the charge / discharge characteristics and the flame retardancy, the electrolytic solution is preferably mixed with an organic solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, . In some cases, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further added to impart nonflammability. In order to improve the high-temperature storage characteristics, carbon dioxide gas may be further added. FEC (Fluoro-Ethylene Carbonate, PRS (Propene sultone), and the like.

In one example, lithium salts such as LiPF ₆ , LiClO ₄ , LiBF ₄ , LiN (SO ₂ CF ₃ ) _2, and the like, are linear with cyclic carbonates of EC or PC, which are highly dielectric solvents, and DEC, DMC, or EMC, which are low viscosity solvents. The lithium salt-containing non-aqueous electrolyte can be prepared by adding to a mixed solvent of carbonate.

The present invention also provides a battery module including the secondary battery as a unit cell, and a battery pack including the battery module.

The battery pack can be used as a power source for a medium and large-sized device requiring high temperature stability, long cycle characteristics, and high rate characteristics.

Examples of the medium-large device include a power tool that is driven by an electric motor; An electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and the like; An electric motorcycle including an electric bike (E-bike) and an electric scooter (E-scooter); An electric golf cart; And a power storage system, but the present invention is not limited thereto.

As described above, the electrode for secondary batteries according to the present invention includes a predetermined amount of a binder, and an electrode mixture indicating a loading amount of 0.1 to 5 mAh / cm ² is applied to the current collector, thus, between electrode active materials or between electrode active materials and In addition to improving the adhesion between the current collector, it is possible to minimize the decrease in electrical conductivity can reduce the internal resistance of the battery.

1 is a graph measuring the adhesion of the negative electrode in Experimental Example 1; And
1 is a graph measuring the resistance change rate according to SOC (state of charge) for each binder content of a secondary battery in Experimental Example 2. FIG.

<Example 1-5, Comparative Example 1>

A negative electrode mixture was prepared by adding a substance having the following composition to NMP, and then coated and dried on an aluminum current collector to prepare a negative electrode for a secondary battery.

Composition of negative electrode mixture Loading amount (mAh / cm ²⁾ Example 1 92.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductor) and 5% by weight PVdF (binder) 1.2 Example 2 89.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductor) and 8% by weight PVdF (binder) 1.2 Example 3 87.5% by weight lithium titanium oxide (cathode active material), 2.5% by weight Super-P (conductor) and 10% by weight PVdF (binder) 1.2 Example 4 84.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductor) and 13% by weight PVdF (binder) 1.2 Example 5 82.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductor) and 15% by weight PVdF (binder) 1.2 Comparative Example 1 77.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductor) and 20% by weight PVdF (binder) 1.2

<Example 6-10, Comparative Example 2>

A negative electrode mixture was prepared by adding a substance having the following composition to water, and then coated and dried on an aluminum current collector to prepare a negative electrode for a secondary battery.

Composition of negative electrode mixture Loading amount (mAh / cm ²⁾ Example 6 92.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductor) and 5% by weight CMC (binder) 1.2 Example 7 89.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductor) and 8% by weight CMC (binder) 1.2 Example 8 87.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductor) and 10% by weight CMC (binder) 1.2 Example 9 84.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductor) and 13% by weight CMC (binder) 1.2 Example 10 82.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductive agent) and 15% by weight CMC (binder) 1.2 Comparative Example 2 77.5% by weight lithium titanium oxide (negative electrode active material), 2.5% by weight Super-P (conductive agent) and 20% by weight CMC (binder) 1.2

<Experimental Example 1>

The adhesion of the negative electrodes prepared in Examples 1 to 10 and Comparative Examples 1 and 2 was measured and shown in FIG. 1.

Referring to FIG. 1, the binders according to Comparative Examples 1 and 2 exhibit very high adhesive strengths, but the adhesive strengths exceed the range of electrode adhesive strengths applicable to actual cell fabrication, which may result in deterioration of physical properties of the battery. .

<Experimental Example 2>

90% by weight of the negative electrode and LiNi _0.5 Mn _1.5 O ₄ (anode active material), 5% by weight of Super-P (conductive agent) and 5% by weight of PVdF (binder) prepared in Examples 3, 5 and Comparative Example 1 An electrode assembly was prepared using a cathode coated with a cathode mixture prepared by adding to NMP and a porous separator made of polypropylene. Thereafter, the electrode assembly was placed in a pouch and the lead wires were connected. Then, an ethylene carbonate (EC) and dimethyl carbonate (DMC) solution having a volume ratio of 1: 1 dissolved in 1 M LiPF ₆ salt was injected into the electrolyte. It sealed and assembled the lithium secondary battery. A resistance change rate according to SOC (state of charge) of the secondary battery is measured and shown in FIG. 2.

According to FIG. 2, it can be seen that the cell resistance of the battery including the negative electrodes of Examples 3 and 5 is lower than that of the battery including the negative electrodes of Comparative Example 1. Referring to FIG. 1, since the negative electrode of Comparative Example 1 has a high adhesive content but a large adhesive force, the cell resistance also increases, and as a result, the performance of the battery may be deteriorated.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (16)

An electrode for secondary batteries in which an electrode mixture including an electrode active material, a binder, and a conductive material is applied to a current collector, wherein the binder is included in an amount of 0.1 to 15 wt% based on the solids content of the electrode mixture, and the electrode mixture is 0.1 A secondary battery electrode, characterized in that for showing a loading of from 5 mAh / cm ² . The method of claim 1, wherein the binder is polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro A secondary battery electrode, characterized in that at least one selected from the group consisting of ethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber and fluorine rubber. The method of claim 1, wherein the binder is a secondary battery electrode, characterized in that contained in 1 to 15% by weight based on the solids content of the electrode mixture. The electrode for secondary batteries of claim 1, wherein the electrode is a positive electrode or a negative electrode or a positive electrode and a negative electrode. The electrode of claim 4, wherein the cathode comprises a lithium metal oxide represented by Chemical Formula 1 as a cathode active material:
Li _x M _y Mn _{2 - y} O _{4 - z z} (1)
Wherein 0 < y < 2, 0 z < 0.2,
M is at least one element selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, ;
A is one or more of an anion of -1 or -2. The electrode of claim 5, wherein the oxide of Formula 1 is represented by the following Formula 2.
Li _x Ni _y Mn _2-y O ₄ (2)
In the above formula, 0.9? X? 1.2 and 0.4? Y? 0.5. The electrode of claim 6, wherein the oxide is LiNi _0.5 Mn _1.5 O ₄ or LiNi _0.4 Mn _1.6 O ₄ . The electrode of claim 4, wherein the negative electrode comprises a lithium metal oxide represented by Chemical Formula 3 as a negative electrode active material:
Li _a M ' _b O _{4-ca c} (3)
In the above formula, M 'is at least one element selected from the group consisting of Ti, Sn, Cu, Pb, Sb, Zn, Fe, In, Al and Zr; a and b are 0.1? a? 4; Is determined according to the oxidation number of M 'in the range of 0.2? B? 4; c is determined according to the oxidation number in the range of 0? c <0.2; A is one or more of an anion of -1 or -2. The method of claim 8, wherein the lithium metal oxide is a secondary battery electrode, characterized in that represented by the formula (4):
Li _a Ti _b O ₄ (4)
In the above formula, 0.5? A? 3, 1? B? 2.5. The electrode of claim 9, wherein the lithium metal oxide is Li _1.33 Ti _1.67 O ₄ or LiTi ₂ O ₄ . A secondary battery comprising the secondary battery electrode according to any one of claims 1 to 10. 12. The secondary battery according to claim 11, wherein the secondary battery is a lithium secondary battery. A battery module comprising the secondary battery according to claim 11 as a unit cell. A battery pack comprising the battery module according to claim 13. A device comprising a battery pack according to claim 14. The device of claim 15, wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a system for power storage.

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