Cathode active material for lithium secondary battery, manufacturing method of same and lithium secondary battery comprising same

Abstract

The present invention relates to a cathode active material for a lithium secondary battery, satisfying expression 1 and comprising a nickel-containing lithium metal oxide having an excess composition of lithium and manganese. [Expression 1] C4.4V / C4.7V ≥ 0.55 In expression 1, C4.7V refers to the total charge capacity during a first charging process with an end voltage of 4.7V with respect to the lithium metal oxide, and C4.4V refers to the charge capacity up to a voltage of 4.4V during the first charging process with an end voltage of 4.7V with respect to the lithium metal oxide.

Description

Positive electrode active material for lithium secondary batteries, method for producing the same, and lithium secondary batteries comprising the same

[0001] The present invention relates to a positive electrode active material for a lithium secondary battery, a method for producing the same, and a lithium secondary battery including the same.

[0002]

[0003] As the scope of application of lithium secondary batteries expands from small electronic devices to electric vehicles and power storage devices, the demand for cathode materials with excellent high energy density and high output characteristics is increasing.

[0004] Lithium-rich layered lithium metal oxides have a very high capacity of over 240 mAh / g and are attracting attention as candidates for next-generation cathode active materials, and research on them is actively being conducted recently.

[0005] However, lithium-rich layered lithium metal oxides utilize oxygen oxidation / reduction reactions in addition to transition metal oxidation / reduction due to their high lithium content and relatively low transition metal ratio within their structures compared to conventional cathode materials. Since these oxygen oxidation / reduction reactions are driven by high voltage during the first charge, they cause electrolyte decomposition due to their high reactivity with the electrolyte on the surface, and thereafter, there is a problem that the cycle life characteristics deteriorate due to the accelerated phase decomposition caused by oxygen gas generation and transition metal elution.

[0006]

[0007] Accordingly, one object of the present invention is to provide a positive electrode active material for a lithium secondary battery having improved lifespan characteristics as a lithium metal oxide having an excess of lithium, a method for producing the same, and a lithium secondary battery including the same.

[0008]

[0009] One embodiment of the present invention provides a cathode active material for a lithium secondary battery, comprising a nickel-containing lithium metal oxide having a lithium and manganese excess composition, and satisfying the following formula 1.

[0010] [Formula 1]

[0011] C 4.4V / C 4.7V ≥ 0.55

[0012] In the above equation 1, C 4.7V means the full charge capacity during the first charge process with a termination voltage of 4.7 V for lithium metal oxide, and C 4.4V It refers to the charge capacity up to a voltage of 4.4 V during the first charge process with a termination voltage of 4.7 V for lithium metal oxide.

[0013] The above lithium metal oxide may have a molar ratio of lithium to lithium metal oxide of 1.05 to 1.15.

[0014] The above lithium metal oxide may have a molar ratio of nickel to the total metal excluding lithium of 0.35 to 0.45.

[0015] The above lithium metal oxide may have a molar ratio of manganese to the total metal excluding lithium of 0.45 to 0.63.

[0016] The above lithium metal oxide may have a molar ratio of cobalt to the total metal excluding lithium of 0.01 to 0.06.

[0017] The above lithium metal oxide may have a molar ratio of nickel to manganese (Ni / Mn) of 0.6 to 0.85.

[0018] The above lithium metal oxide may have a molar ratio of cobalt to nickel (Co / Ni) of 0.03 to 0.058.

[0019] The above lithium metal oxide may have a molar ratio of cobalt to manganese (Co / Mn) of 0.032 to 0.04.

[0020] The above lithium metal oxide may have a c-axis lattice constant of 14.25 to 14.31 Å.

[0021] The lithium metal oxide has a unit cell volume of 102.3 to 103.0 Å.3 It could be.

[0022] The above lithium metal oxide may have a peak area ratio of [A(006)+A(102)] / A(101) of 0.41 to 0.51 when analyzing an X-ray diffraction pattern.

[0023]

[0024] The above lithium metal oxide can be represented by the following chemical formula 1.

[0025] [Chemical Formula 1]

[0026] Li 1+a (Ni x Co y Mn z M w ) 1-a O 2-b A b

[0027] In the above chemical formula 1, 0.05≤a≤0.15, 0.35≤x≤0.45, 0.01≤y≤0.06, 0.45≤z≤0.63, 0≤w≤0.1, 0≤b≤0.1, x+y+z+w=1, M is Zr, Al, B, Y, Mg, Ti, Nb, W, Sc, Si, V, Fe, Y, Mo, Ce, Hf, Ta, La, Sr, Sn, Sb, Zn, Cu, Ge, Ru, Ir or a combination thereof, and A is PO4, BO3, CO3, NO 3, F, Cl, Br, I or a combination of these.

[0028]

[0029] A cathode active material for a lithium secondary battery according to one embodiment of the present invention includes a lithium metal oxide having an excess composition of lithium and manganese, and the charging behavior of the lithium metal oxide during the first charging process is controlled, thereby improving the life characteristics.

[0030]

[0031] The terms first, second, and third, etc., are used to describe, but are not limited to, various parts, components, regions, layers, and / or sections. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used herein, the singular forms "singular" and "comprising" include plural forms as well, unless the context clearly dictates otherwise. The word "comprising" as used herein specifies a particular feature, region, integer, step, operation, element, and / or component, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0033] When a part is referred to as being "on" or "over" another part, it can be directly on or over the other part, or there may be other parts intervening. Conversely, when a part is referred to as being "directly on" another part, there are no other parts intervening.

[0034] Although not defined otherwise, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or overly formal unless otherwise defined.

[0035] Also, unless otherwise stated, % means weight%, and 1 ppm is 0.0001 weight%.

[0036] In this specification, the term "combination(s) thereof" described in the expression in the Makushi format means one or more mixtures or combinations selected from the group consisting of the components described in the expression in the Makushi format, and means including any one or more selected from the group consisting of said components.

[0037] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0038]

[0039] 1. Positive active material

[0040] According to one embodiment of the present invention, a cathode active material for a lithium secondary battery comprises a lithium metal oxide having a lithium and manganese-rich composition. Although the lithium and manganese-rich lithium metal oxide has a slightly lower nickel content than a lithium metal oxide having a conventional composition, it can undergo oxidation / reduction reactions of not only transition metal cations but also anions (oxygen) during battery operation. Furthermore, since the excess lithium can exist in the transition metal layer in addition to the lithium layer, the insertion and deintercalation efficiency of lithium ions can be increased. Consequently, the initial discharge capacity can be improved compared to a cathode material having a conventional NCM composition. Furthermore, it is economically advantageous because the relatively expensive nickel and cobalt contents can be reduced and the inexpensive manganese content can be increased.

[0041] Meanwhile, the lithium metal oxide according to the present invention may be in the form of secondary particles formed by agglomeration of a plurality of primary particles.

[0042] In this specification, “primary particle” means the smallest particle unit that can be distinguished as a single lump when observing a cross-section of a positive electrode active material through a scanning electron microscope (SEM), and may be composed of a single crystal grain or multiple crystal grains. In addition, in this specification, “crystal grain” means a distinct region in the form of a lattice structure in which atoms within a primary particle form a lattice structure with a certain direction.

[0043] However, as mentioned above, lithium metal oxides with a lithium and manganese excess composition utilize oxygen (anion) oxidation / reduction reactions in addition to the oxidation / reduction reactions of transition metal cations due to their high lithium content and relatively low transition metal ratio in the structure compared to lithium metal oxides with a normal composition. Since this oxygen oxidation / reduction reaction is driven at a high voltage during the first charge, it causes electrolyte decomposition due to its high reactivity with the electrolyte on the surface, and there is a problem that the life characteristics deteriorate due to the acceleration of oxygen gas generation during subsequent cycles.

[0044] Accordingly, the inventors of the present invention have conducted repeated research on a method for improving the life characteristics of a lithium metal oxide having an excess composition of lithium and manganese, and have discovered that the effect can be achieved by controlling the charging pattern during the first charging process of the lithium metal oxide, thereby completing the present invention.

[0045]

[0046] Specifically, the lithium metal oxide having a lithium and manganese excess composition according to the present invention satisfies the following equation 1.

[0047] [Formula 1]

[0048] C 4.4V / C 4.7V ≥ 0.55

[0049] In the above equation 1, C 4.7V means the full charge capacity during the first charge process with a termination voltage of 4.7 V for lithium metal oxide, and C 4.4VIt refers to the charge capacity up to a voltage of 4.4 V during the first charge process with a termination voltage of 4.7 V for lithium metal oxide.

[0050] C above 4.4V / C 4.7V The value can be more specifically 0.55 to 0.75 or 0.59 to 0.665. C 4.4V / C 4.7V The fact that the value is sufficiently large as in the above range may mean that the oxidation / reduction reaction amount of transition metal cations is high and the oxidation / reduction reaction amount of oxygen (anion) is relatively low due to the high Ni and Co contents. On the other hand, if the oxidation / reduction reaction amount of oxygen (anion) is too high, it may cause the deterioration of the life characteristics of the battery. Therefore, C of lithium metal oxide 4.4V / C 4.7V When the value satisfies the above range, the life characteristics of the battery can be improved. However, C 4.4V / C 4.7V If the value is too large, the phase change of the active material may occur, which may minimize the effect of improving the life characteristics, and the utilization of oxygen (anion) reaction may be too low, which may lower the capacity characteristics. On the other hand, C 4.4V / C 4.7V When the values ​​are more specific to the above range, the aforementioned C 4.4V / C 4.7V The effect of improving electrochemical characteristics by adjusting the value can be more preferably implemented.

[0051] Meanwhile, the above C 4.4V / C 4.7V Specific battery manufacturing methods and charging conditions for measuring values ​​may be as follows.

[0052] [Battery manufacturing method]

[0053] The slurry for manufacturing the electrode plate is mixed with the manufactured positive electrode active material: conductive material (carbon black, denka black): binder (PVDF, KF1100) = 92.5:3.5:4 wt%, and the viscosity is adjusted so that the solid concentration is approximately 30% by adding NMP (N-Methyl-2-pyrrolidone). The manufactured slurry is coated on a 20㎛ thick Al foil using a doctor blade, dried, and then rolled. At this time, the electrode loading is approximately 14 mg / cm 2 It is done as follows.

[0054] The electrolyte is 1M LiPF6in EC:EMC=3:7(vol%), and a CR2032 coin cell is manufactured using a PP separator and a lithium negative electrode (200㎛, Honzo metal).

[0055] [Charging conditions]

[0056] After manufacturing the above coin cell, it was aged at 25°C for 10 hours and then formed at 25°C. At this time, to evaluate the initial charge capacity, 200 mAh / g was used as the 1C reference capacity and it was charged to 4.7 V at a constant current of 0.1C.

[0057]

[0058] Hereinafter, the composition of the lithium metal oxide according to the present invention will be described in more detail.

[0059] First, the lithium metal oxide according to the present invention may have a molar ratio of lithium to lithium metal oxide of 1.05 to 1.15, more specifically, 1.08 to 1.13 or 1.09 to 1.13. As the molar ratio of lithium to lithium metal oxide increases, the amount of lithium that can participate in the insertion and de-insertion of lithium ions increases, thereby improving the capacity characteristics. However, if the molar ratio of lithium to lithium metal oxide is too large, a problem of phase stability may occur due to excessive occurrence of oxidation / reduction reactions of oxygen anions, which may result in a deterioration of the life characteristics. In addition, when the molar ratio of lithium to lithium metal oxide satisfies the above range, C 4.4V / C 4.7V The value can be appropriately obtained within the range according to the present invention. Meanwhile, when the molar ratio of lithium to lithium metal oxide is more specifically defined within the above range, the effect of improving electrochemical properties according to the aforementioned molar ratio control can be more preferably implemented.

[0060] In addition, the lithium metal oxide according to the present invention may have a molar ratio of nickel to the entire metal excluding lithium of 0.35 to 0.45, more specifically, 0.37 to 0.43. If the content of nickel is too low, the oxidation / reduction reaction amount of the transition metal cation may be low, and the effect of improving the life characteristics may be minimal. If the content of nickel is too high, the oxidation / reduction reaction amount of the oxygen anion may be reduced, and the capacity characteristics may deteriorate. In addition, when the nickel content satisfies the above range, C 4.4V / C 4.7V The values ​​can be appropriately obtained within the range according to the present invention. Meanwhile, when the nickel content is more specifically defined within the above range, the electrochemical characteristic improvement effect due to the aforementioned nickel content control can be more preferably realized.

[0061] In addition, the lithium metal oxide according to the present invention may have a molar ratio of manganese to the entire metal excluding lithium of 0.45 to 0.63, more specifically, 0.53 to 0.63. If the content of manganese is too low, the manufacturing cost increases, the safety of the active material decreases, and the amount of oxidation / reduction reaction of oxygen anions decreases, which may lower the capacity characteristics. If the content of manganese is too high, the amount of oxidation / reduction reaction of oxygen anions increases too much, which may lower the life characteristics, and there may be a problem of manganese being eluted. In addition, when the manganese content satisfies the above range, C 4.4V / C 4.7V The values ​​can be appropriately obtained within the range according to the present invention. Meanwhile, when the manganese content is more specifically defined within the above range, the aforementioned effect of improving electrochemical properties by controlling the manganese content can be more preferably realized.

[0062] In addition, the lithium metal oxide according to the present invention may have a molar ratio of cobalt to the entire metal excluding lithium of 0.01 to 0.06, more specifically, 0.01 to 0.04 or 0.01 to 0.03. If the content of cobalt is too low, the oxidation / reduction reaction amount of the transition metal cation may be low, so that the effect of improving the life characteristics may be minimal. In addition, the electronic conductivity may be low, so that the output characteristics may be deteriorated. If the content of cobalt is too high, the oxidation / reduction reaction amount of the oxygen anion may be reduced, so that the capacity characteristics may be deteriorated. In addition, when the cobalt content satisfies the above range, C 4.4V / C 4.7V The values ​​can be appropriately obtained within the range according to the present invention. Meanwhile, when the cobalt content is more specifically defined within the above range, the aforementioned effect of improving electrochemical properties by controlling the cobalt content can be more preferably realized.

[0063] In addition, the lithium metal oxide according to the present invention may have a molar ratio of nickel to manganese (Ni / Mn) of 0.6 to 0.85, more specifically, 0.63 to 0.80. When the molar ratio of nickel to manganese (Ni / Mn) satisfies the above range, the oxidation / reduction reaction amount of the transition metal cation is more appropriately controlled, and accordingly, C 4.4V / C 4.7V The value can be appropriately obtained within the range according to the present invention. In addition, the crystal structure of the lithium metal oxide is better controlled so that the X-ray diffraction analysis properties such as the c-axis lattice constant and the unit cell volume (see the following description) can be appropriately obtained within the range according to the present invention. Consequently, when the molar ratio of nickel to manganese (Ni / Mn) satisfies the above range, the effect of improving the life characteristics of the positive electrode active material can be more preferably implemented, and further, the capacity and output characteristics can also be excellently implemented. Meanwhile, when the molar ratio of nickel to manganese (Ni / Mn) is more specifically within the above range, the effect of improving the electrochemical characteristics according to the aforementioned molar ratio control can be more preferably implemented.

[0064] In addition, the lithium metal oxide according to the present invention may have a molar ratio of cobalt to nickel (Co / Ni) of 0.03 to 0.058, more specifically, 0.035 to 0.055. When the molar ratio of cobalt to nickel (Co / Ni) satisfies the above range, the oxidation / reduction reaction amount of the transition metal cation is more appropriately controlled, and accordingly, C 4.4V / C 4.7VThe value can be appropriately obtained within the range according to the present invention. In addition, the crystal structure of the lithium metal oxide is better controlled so that the X-ray diffraction analysis properties such as the c-axis lattice constant and the unit cell volume (see the following description) can be appropriately obtained within the range according to the present invention. Consequently, when the molar ratio of cobalt to nickel (Co / Ni) satisfies the above range, the effect of improving the life characteristics of the positive electrode active material can be more preferably implemented, and further, the capacity and output characteristics can also be excellently implemented. Meanwhile, when the molar ratio of cobalt to nickel (Co / Ni) is more specifically within the above range, the effect of improving the electrochemical characteristics according to the aforementioned molar ratio control can be more preferably implemented.

[0065] In addition, the lithium metal oxide according to the present invention may have a molar ratio of cobalt to manganese (Co / Mn) of 0.032 to 0.04, more specifically, 0.032 to 0.038. When the molar ratio of cobalt to manganese (Co / Mn) satisfies the above range, the oxidation / reduction reaction amount of the transition metal cation is more appropriately controlled, and accordingly, C 4.4V / C 4.7V The value can be appropriately obtained within the range according to the present invention. In addition, the crystal structure of the lithium metal oxide is better controlled so that the X-ray diffraction analysis properties such as the c-axis lattice constant and the unit cell volume (see the following description) can be appropriately obtained within the range according to the present invention. Consequently, when the molar ratio of cobalt to manganese (Co / Mn) satisfies the above range, the effect of improving the life characteristics of the positive electrode active material can be more preferably implemented, and further, the capacity and output characteristics can also be excellently implemented. Meanwhile, when the molar ratio of cobalt to manganese (Co / Mn) is more specifically within the above range, the effect of improving the electrochemical characteristics according to the aforementioned molar ratio control can be more preferably implemented.

[0066] Meanwhile, the lithium metal oxide according to the present invention may have a c-axis lattice constant of 14.25 to 14.31 Å, and more specifically, may have a c-axis lattice constant of 14.26 to 14.30 Å. When the c-axis lattice constant of the lithium metal oxide satisfies the above range, the life-cycle characteristic improvement effect according to the present invention can be preferably implemented, and the output characteristics can be more preferably implemented. In addition, the c-axis lattice constant within the above range may be a value obtained when the composition and sintering temperature of the lithium metal oxide are appropriately controlled within the range according to the present invention. Meanwhile, when the range of the c-axis lattice constant is more specifically defined within the above range, the electrochemical characteristic improvement effect according to the c-axis lattice constant control mentioned above can be more preferably implemented.

[0067] In addition, the lithium metal oxide according to the present invention has a unit cell volume of 102.3 to 103.0 Å. 3 may be, more specifically, 102.4 to 102.75 Å 3 It can be. When the unit cell volume of lithium metal oxide satisfies the above range, the life characteristic improvement effect according to the present invention can be preferably implemented, and the output characteristic can be implemented more preferably. In addition, the unit cell volume of the above range can be a value obtained when the composition of lithium metal oxide, sintering temperature, etc. are appropriately controlled within the range according to the present invention. Meanwhile, when the range of the unit cell volume is more specifically specified within the above range, the electrochemical characteristic improvement effect according to the unit cell volume control mentioned above can be more preferably implemented.

[0068] In addition, the lithium metal oxide according to the present invention may have a [A(006)+A(102)] / A(101) peak area ratio of 0.41 to 0.51, more specifically, 0.42 to 0.469, when analyzing the X-ray diffraction pattern. When the [A(006)+A(102)] / A(101) peak area ratio of the lithium metal oxide satisfies the above range, the life characteristic improvement effect according to the present invention can be preferably implemented, and the output characteristics can be more preferably implemented. In addition, the [A(006)+A(102)] / A(101) peak area ratio in the above range may be a value obtained when the composition of the lithium metal oxide, the sintering temperature, etc. are appropriately controlled within the range according to the present invention. Meanwhile, when the range of the [A(006)+A(102)] / A(101) peak area ratio is further specified within the above range, the effect of improving electrochemical properties according to the aforementioned peak area ratio control can be more preferably implemented.

[0069] Meanwhile, the c-axis lattice constant, unit cell volume, and [A(006)+A(102)] / A(101) peak area ratio of lithium metal oxide can be derived by measuring the positive electrode active material powder using Cu Kα rays as an X-ray diffraction (XRD) light source in a diffraction angle (2theta) range of 14 to 100 degrees at a scan speed of 2 degrees / min.

[0070] The lithium metal oxide according to the present invention can be more specifically represented by the following chemical formula 1.

[0071] [Chemical Formula 1]

[0072] Li 1+a (Ni x Co y Mn z M w ) 1-a O 2-b A b

[0073] In the above chemical formula 1, 0.05≤a≤0.15, 0.35≤x≤0.45, 0.01≤y≤0.06, 0.45≤z≤0.63, 0≤w≤0.1, 0≤b≤0.1, x+y+z+w=1, M is Zr, Al, B, Y, Mg, Ti, Nb, W, Sc, Si, V, Fe, Y, Mo, Ce, Hf, Ta, La, Sr, Sn, Sb, Zn, Cu, Ge, Ru, Ir or a combination thereof, and A is PO4, BO3, CO3, NO 3, F, Cl, Br, I or a combination of these.

[0074]

[0075] The lithium metal oxide according to the present invention can be manufactured by a step of preparing a metal precursor; and a step of mixing the metal precursor and a lithium raw material and then calcining them to form a lithium metal oxide.

[0076] Hereinafter, the method for producing lithium metal oxide according to the present invention will be described in more detail step by step.

[0077]

[0078] First, prepare a metal precursor.

[0079] The above metal precursor may more specifically be a metal hydroxide.

[0080] The above metal precursor may be prepared by, for example, adding a complexing agent-containing solution and a pH adjusting agent-containing solution to a metal-containing solution including a nickel raw material, a manganese raw material, and optionally a cobalt raw material, and performing a co-precipitation reaction.

[0081] The above nickel raw material is not particularly limited as long as it is used in the art for manufacturing a positive electrode active material precursor. For example, the nickel raw material may be a nickel-containing sulfate, acetate, nitrate, halide, sulfide, hydroxide, oxide, or oxyhydroxide, and specifically, may be NiSO4, NiSO4·6H2O, Ni(OH)2, NiO, NiOOH, NiCO3·2Ni(OH)2·4H2O, NiC2O2·2H2O, Ni(NO3)2·6H2O, fatty acid nickel salt, nickel halide, or a combination thereof, but is not limited thereto.

[0082] The above cobalt raw material is not particularly limited as long as it is used in the art for manufacturing a positive electrode active material precursor. For example, the cobalt raw material may be a cobalt-containing sulfate, acetate, nitrate, halide, sulfide, hydroxide, oxide, or oxyhydroxide, and specifically, CoSO 4, It may be, but is not limited to, CoSO4ㆍ7H2O, Co(OH)2, CoOOH, Co(OCOCH3)2ㆍ4H2O, Co(NO3)2ㆍ6H2O or a combination thereof.

[0083] The manganese raw material is not particularly limited as long as it is used in the art for manufacturing a precursor of a cathode active material. For example, the manganese raw material may be a manganese-containing sulfate, acetate, nitrate, halide, sulfide, hydroxide, oxide, oxyhydroxide, or a combination thereof, and specifically, may be a manganese salt such as MnSO4, MnCO3, Mn(NO3)2, manganese acetate, manganese dicarboxylic acid salt, manganese citrate, and manganese fatty acid salt, manganese oxide such as Mn2O3, MnO2, and Mn3O4, oxyhydroxide, manganese chloride, or a combination thereof, but is not limited thereto.

[0084] The above metal-containing solution may be prepared by adding nickel raw material, manganese raw material, and optionally cobalt raw material to a solvent, specifically water, or a mixture of water and an organic solvent (e.g., alcohol, etc.) that can be uniformly mixed with water.

[0085] The above complexing agent-containing solution performs the function of forming a complex, and may include, but is not limited to, NH3, NH4OH, (NH4)2SO4, NH4NO3, NH4Cl, CH3COONH4, NH4CO3 or a combination thereof as the complexing agent. Meanwhile, the complexing agent-containing solution may be used in the form of an aqueous solution, and at this time, water or a mixture of water and an organic solvent (e.g., alcohol, etc.) that can be uniformly mixed with water may be used as the solvent.

[0086] The above pH adjusting agent-containing solution acts as a precipitant or pH adjusting agent, and may include an alkaline compound such as a hydroxide of an alkali metal or alkaline earth metal, such as NaOH, KOH, or Ca(OH)2, a hydrate thereof, or a combination thereof. Meanwhile, the pH adjusting agent-containing solution may also be used in the form of an aqueous solution, and at this time, water or a mixture of water and an organic solvent (e.g., alcohol, etc.) that can be uniformly mixed with water may be used as the solvent. At this time, the pH adjusting agent-containing solution may be added in an amount such that the pH of the reaction solution becomes 10 to 13.

[0087] The above coprecipitation reaction can be performed under an inert atmosphere such as nitrogen or argon, can be performed at a temperature of 30 to 70°C, and can be performed at a pH of 10 to 13.

[0088] Nickel-manganese-cobalt hydroxide particles are generated through the above process and precipitated within the reaction solution. The precipitated precursor particles can be separated, washed, and dried using conventional methods to obtain the precursor. The precursor may be a secondary particle formed by the agglomeration of primary particles.

[0089] At this time, the molar ratio of nickel, cobalt, and manganese in the precursor can be controlled by controlling the concentration of nickel raw material, cobalt raw material, and manganese raw material.

[0090] Accordingly, the molar ratio of manganese (Mn) to metal (M) in the metal precursor (Mn / M) may be 0.45 to 0.63. In addition, the molar ratio of nickel (Ni) to metal (M) in the metal precursor (Ni / M) may be 0.35 to 0.45. In addition, the molar ratio of cobalt (Co) to metal (M) in the metal precursor (Co / M) may be 0.01 to 0.06. The technical significance of adjusting the content of each metal is as described above, and thus is omitted.

[0091]

[0092] Next, the metal precursor and lithium raw material are mixed and then calcined to form lithium metal oxide.

[0093] At this time, the amount of lithium raw material input can be adjusted so that the molar ratio of lithium to the finally formed lithium metal oxide is 1.05 to 1.15. The technical significance thereof is as described above and therefore is omitted.

[0094] In addition, at this time, the calcination can be performed at a temperature of 750 to 950°C, and more specifically, it can be performed at a temperature of 780 to 940°C or 830 to 930°C. When the calcination temperature satisfies the above range, the oxidation / reduction reaction amount of the transition metal cation is more appropriately controlled, and accordingly, C 4.4V / C 4.7VThe values ​​can be appropriately obtained within the range according to the present invention. In addition, the crystal structure of the lithium metal oxide is better controlled, so that the X-ray diffraction analysis properties such as the c-axis lattice constant and the unit cell volume can be appropriately obtained within the range according to the present invention. Consequently, when the sintering temperature satisfies the above range, the effect of improving the life characteristics of the positive electrode active material can be more preferably implemented, and further, the capacity and output characteristics can also be excellently implemented.

[0095] Also, at this time, the calcination can be performed for 5 to 15 hours. When the calcination time satisfies the above range, the oxidation / reduction reaction amount of the transition metal cation is more appropriately controlled, and accordingly, C 4.4V / C 4.7V The values ​​can be appropriately obtained within the range according to the present invention. In addition, the crystal structure of the lithium metal oxide is better controlled, so that the X-ray diffraction analysis properties such as the c-axis lattice constant and the unit cell volume can be appropriately obtained within the range according to the present invention. Consequently, when the sintering time satisfies the above range, the effect of improving the life characteristics of the positive electrode active material can be more preferably implemented, and further, the capacity and output characteristics can also be excellently implemented.

[0096] Additionally, at this time, the firing can be performed in an air atmosphere or an oxygen (O2) atmosphere.

[0097]

[0098] The lithium raw material may be lithium-containing sulfate, nitrate, acetate, carbonate, oxalate, citrate, halide, hydroxide, or oxyhydroxide, and is not particularly limited as long as it can be dissolved in water. Specifically, the lithium raw material may be, but is not limited to, Li2CO3, LiNO3, LiNO2, LiOH, LiOHㆍH2O, LiH, LiF, LiCl, LiBr, LiI, CH3COOLi, Li2O, Li2SO4, CH3COOLi, Li3C6H5O7, or a combination thereof.

[0099] Meanwhile, a doping raw material may be further optionally mixed in as needed. At this time, the doping raw material may be a compound containing Zr, Al, B, Y, Mg, Ti, Nb, W, Sc, Si, V, Fe, Y, Mo, Ce, Hf, Ta, La, Sr, Sn, Sb, Zn, Cu, Ge, Ru, Ir, or a combination thereof.

[0100]

[0101] 2. Cathode ray and lithium secondary battery

[0102] Another embodiment of the present invention provides a positive electrode for a lithium secondary battery comprising the positive electrode active material described above.

[0103] More specifically, the positive electrode may include a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector, and including the positive electrode active material described above.

[0104] The positive electrode current collector is not particularly limited as long as it is conductive and does not cause a chemical change in the battery, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. may be used. In addition, the positive electrode current collector may typically have a thickness of 3 to 500 μm, and fine unevenness may be formed on the surface of the positive electrode current collector to increase the adhesion of the positive electrode active material. For example, the positive electrode current collector may be used in various forms such as a film, sheet, foil, net, porous body, foam, or non-woven fabric.

[0105] The above-described positive electrode active material layer may include a binder and / or a conductive material together with the above-described positive electrode active material.

[0106] At this time, the binder plays a role of improving the adhesion between the positive electrode active material particles and the adhesive strength between the positive electrode active material and the positive electrode current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer rubber (EPDM rubber), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one kind alone or a mixture of two or more kinds thereof may be used, but is not limited thereto. The binder may be included in an amount of 1 to 30 wt% based on the total weight of the positive electrode active material layer.

[0107] And, the conductive material is used to provide conductivity to the electrode, and in the battery to be constructed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without any special restrictions. Specific examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, and carbon fiber; metal powder or metal fiber such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like. One type alone or a mixture of two or more types among these may be used, but the present invention is not limited thereto. The conductive material may typically be included in an amount of 1 to 30 wt% based on the total weight of the positive electrode active material layer.

[0108] The above positive electrode can be manufactured according to a conventional positive electrode manufacturing method, except that the above positive electrode active material is used.

[0109] Specifically, the positive electrode can be manufactured by applying a composition for forming a positive electrode active material layer, including the positive electrode active material described above and optionally a binder, a conductive agent, or a solvent, on a positive electrode current collector, followed by drying and rolling. At this time, the types and contents of the positive electrode active material, binder, and conductive agent are as described above.

[0110] The solvent may be a solvent generally used in the relevant technical field, such as dimethylsulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water. One of these may be used alone or a mixture of two or more thereof may be used. The amount of the solvent used is sufficient to dissolve or disperse the positive electrode active material, conductive material, and binder, taking into account the coating thickness and manufacturing yield of the slurry, and to have a viscosity that can exhibit excellent thickness uniformity when applied thereafter for manufacturing the positive electrode.

[0111] Alternatively, the positive electrode may be manufactured by casting the composition for forming the positive electrode active material layer on a separate support, and then laminating the resulting film on a positive electrode current collector by peeling it off from the support.

[0112]

[0113] Another embodiment of the present invention provides a lithium secondary battery including the positive electrode for a lithium secondary battery as described above.

[0114] The above lithium secondary battery may more specifically include a positive electrode; a negative electrode; a separator; and an electrolyte.

[0115] The above lithium secondary battery may optionally further include a battery container that houses an electrode assembly of the positive electrode, negative electrode, and separator, and a sealing member that seals the battery container.

[0116] The above negative electrode may include a negative electrode current collector and a negative electrode active material layer positioned on the negative electrode current collector.

[0117] The negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, the negative electrode current collector can typically have a thickness of 3 to 500 ㎛, and like the positive electrode current collector, fine unevenness can be formed on the surface of the current collector to strengthen the bonding strength of the negative electrode active material. For example, it can be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc.

[0118] The negative electrode active material layer may optionally include a binder and a conductive material together with the negative electrode active material. As an example, the negative electrode active material layer may be manufactured by applying a composition for forming a negative electrode active material layer comprising the negative electrode active material and optionally a binder and a conductive material onto a negative electrode current collector and drying the composition, or by casting the negative electrode forming composition onto a separate support and then laminating the resulting film onto a negative electrode current collector by peeling the film off from the support.

[0119] As the negative electrode active material, a compound capable of reversible intercalation and deintercalation of lithium may be used. Specific examples thereof include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds capable of alloying with lithium, such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloy, Sn alloy, and Al alloy; metallic oxides capable of doping and dedoping lithium, such as SiOβ (0 < β < 2), SnO2, vanadium oxide, and lithium vanadium oxide; or composites comprising the metallic compounds and carbonaceous materials, such as Si-C composites or Sn-C composites, and any one or a mixture of two or more of these may be used. In addition, a metallic lithium thin film may be used as the negative electrode active material. In addition, both low-crystalline carbon and high-crystalline carbon may be used as the carbonaceous material. Representative examples of low-crystalline carbon include soft carbon and hard carbon, and representative examples of high-crystalline carbon include natural graphite or artificial graphite in the form of amorphous, plate-like, flaky, spherical, or fiber-like forms, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and high-temperature calcined carbon such as petroleum or coal tar pitch derived cokes.

[0120] The above binder and conductive material may be the same as those described above for the positive electrode.

[0121]

[0122] The above separator separates the negative electrode and the positive electrode and provides a passage for lithium ions to move. Any separator commonly used as a separator in lithium secondary batteries can be used without any particular restrictions. In particular, a separator having low resistance to ion movement of the electrolyte and excellent electrolyte moisture absorption capacity is preferable. Specifically, a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof, may be used. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. may be used. In addition, a coated separator containing a ceramic component or a polymer material to secure heat resistance or mechanical strength may be used, and may optionally be used in a single-layer or multi-layer structure.

[0123]

[0124] The above electrolyte may include, but is not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in the manufacture of lithium secondary batteries.

[0125] Specifically, the organic liquid electrolyte may include an organic solvent and a lithium salt.

[0126] The organic solvent may be used without any particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent may include ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; Carbonate solvents such as dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (wherein R is a C2 to C20 linear, branched, or cyclic hydrocarbon group, and may include a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes can be used. Among these, a carbonate solvent is preferable, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of the battery and a linear carbonate compound having low viscosity (e.g., ethyl methyl carbonate, dimethyl carbonate, or diethyl carbonate, etc.) is more preferable.In this case, the performance of the electrolyte may be excellent when the cyclic carbonate and the chain carbonate are mixed and used in a volume ratio of about 1:1 to about 1:9.

[0127] The lithium salt may be used without any particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. Specifically, the lithium salt may be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2. LiCl, LiI, or LiB(C2O4)2. It is preferable that the concentration of the lithium salt be used within the range of 0.1 to 2.0 M. When the concentration of the lithium salt is within the above range, the electrolyte can exhibit excellent electrolyte performance because it has appropriate conductivity and viscosity, and lithium ions can move effectively.

[0128] In addition to the electrolyte components, the electrolyte may further include one or more additives, such as haloalkylene carbonate compounds such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, cyclic ethers, ethylene diamine, n-glyme, hexamethylphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, or aluminum trichloride, for the purpose of improving the life characteristics of the battery, suppressing battery capacity decrease, and improving the discharge capacity of the battery. At this time, the additives may be included in an amount of 0.1 to 5 wt% based on the total weight of the electrolyte.

[0129] As described above, a lithium secondary battery including a cathode active material according to the present invention stably exhibits excellent discharge capacity, output characteristics, and capacity retention, and is therefore useful in portable devices such as mobile phones, laptop computers, and digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs).

[0130] Accordingly, another embodiment of the present invention provides a battery module including the lithium secondary battery as a unit cell and a battery pack including the same.

[0131] The above battery module or battery pack can be used as a power source for one or more medium- to large-sized devices, such as a power tool; an electric vehicle (EV), a hybrid electric vehicle, and a plug-in hybrid electric vehicle (PHEV); or a power storage system.

[0132]

[0133] Hereinafter, embodiments of the present invention will be described in more detail through examples. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0134]

[0135] Example 1

[0136] (1) Manufacturing of positive electrode active material

[0137] Ni 0.40 Co 0.02 Mn 0.58 A lithium metal oxide with a lithium and manganese excess composition was prepared by mixing a metal precursor with a composition of (OH)2 and LiOH·H2O with Li / Me(Ni+Co+Mn)=1.22 and calcining at 800°C for 10 hours in an air atmosphere. The composition of the synthesized lithium metal oxide was Li 1.10 Ni 0.36 Co0.02 Mn 0.52 It was O2.

[0138] (2) Lithium secondary battery manufacturing

[0139] The slurry for manufacturing the electrode plate was mixed with the above-mentioned positive electrode active material: conductive material (carbon black, denka black): binder (PVDF, KF1100) = 92.5:3.5:4 wt%, and the viscosity was adjusted so that the solid concentration was approximately 30% by adding NMP (N-Methyl-2-pyrrolidone). The manufactured slurry was coated on a 20 μm thick Al foil using a doctor blade, dried, and then rolled. At this time, the electrode loading amount was approximately 14 mg / cm 2 It was.

[0140] The electrolyte used was 1M LiPF6in EC:EMC=3:7 (vol%), and a CR2032 coin cell was manufactured using a PP separator and a lithium negative electrode (200㎛, Honzo metal).

[0141]

[0142] Example 2

[0143] A positive electrode active material and a lithium secondary battery were manufactured in the same manner as in Example 1, except that the sintering temperature was set to 850°C.

[0144]

[0145] Example 3

[0146] A positive electrode active material and a lithium secondary battery were manufactured in the same manner as in Example 1, except that the sintering temperature was set to 900°C.

[0147]

[0148] Comparative Example 1

[0149] Ni 0.33 Co 0.09 Mn 0.58A cathode active material and a lithium secondary battery were manufactured in the same manner as in Example 3, except that the metal precursor of (OH)2 composition was mixed with LiOH·H2O and Li / Me(Ni+Co+Mn)=1.31. The composition of the synthesized lithium metal oxide was Li 1.13 Ni 0.29 Co 0.08 Mn 0.50 It was O2.

[0150]

[0151] Comparative Example 2

[0152] Ni 0.33 Co 0.02 Mn 0.65 A cathode active material and a lithium secondary battery were manufactured in the same manner as in Example 3, except that the metal precursor of (OH)2 composition was mixed with LiOH·H2O and Li / Me(Ni+Co+Mn)=1.25. The composition of the synthesized lithium metal oxide was Li 1.11 Ni 0.29 Co 0.02 Mn 0.58 It was O2.

[0153]

[0154] Comparative Example 3

[0155] Ni 0.3 Mn 0.7 A cathode active material and a lithium secondary battery were manufactured in the same manner as in Example 3, except that the metal precursor of (OH)2 composition was mixed with LiOH·H2O and Li / Me(Ni+Co+Mn)=1.29. The composition of the synthesized lithium metal oxide was Li 1.13 Ni 0.26 Mn 0.61 It was O2.

[0156]

[0157] Table 1 below summarizes the composition and firing process conditions of examples and comparative examples.

[0158] Composition and firing process conditionsLi (1+a)Ni(x)Co(y)Mn(z)Ni(x) / Mn(z)Co(y) / Ni(x)Co(y) / Mn(z)Firing temperature (℃)Firing time (hour)Firing atmosphereExample 11.10.40.020.580.6900.0500.03480010AirExample 21.10.40.020.580.6900.0500.03485010AirExample 31.10.40.020.580.6900.0500.03490010AirComparative example 11.130.330.090.580.5690.2730.15590010Air (air) Comparison example 21.110.330.020.650.5080.0610.03190010Air (air) Comparison example 31.130.300.70.4290.0000.00090010Air (air)

[0159] Tables 2 and 3 below summarize the results of the evaluation of the properties and electrochemical characteristics of the positive electrode active material according to Experimental Examples 2 and 3 described below.

[0160] c-axis lattice constant (Å) Unit lattice volume (Å) 3 )[I(006)+I(102)] / I(101)Example 114.3054102.89530.471Example 214.2981102.66680.466Example 314.2895102.43730.443Comparative Example 114.2419101.23790.407Comparative Example 214.3154100.97190.529Comparative Example 314.3385102.2060.400

[0161] First cycle (0.1C) Output characteristics Life characteristics ~4.4V Charge capacity (C) 4.4V )(mAh / g)~4.7V charging capacity(C 4.7V )(mAh / g)C 4.4V / C 4.7V Initial discharge capacity (mAh / g) Initial efficiency (%) Average discharge voltage (V) 2C / 0.2C Discharge capacity ratio (%) 50 st / 1 thDischarge capacity ratio (%) Example 1 160.123 8.80.67 211.38 8.50 3.79 178.30 9 2.90 Example 2 162.92 47.30 659 217.38 7.80 3.82 68 1.90 9 4.60 Example 3 164.126 0.60 3225 86.30 3.85 784.70 9 6.60 Comparative example 1 156.5 29 2.40.535 247.68 4.70 3.76 80.80 9 1.60 Comparative example 2 130.326 5.10.49 1229 86.30 3.7 1279.20 89.30 Comparative example 3124285.70.434242.184.703.69378.1088.10

[0162]

[0163] Experimental Example 1: Evaluation of the properties of positive electrode active materials

[0164] For each of the positive electrode active material powders of the examples and comparative examples, Cu Kα rays were used as an X-ray diffraction light source, and measurements were made at a diffraction angle (2theta) range of 14 degrees to 100 degrees at a scan speed of 2 degrees / min to derive the values ​​of the c-axis lattice constant, unit cell volume, and [I(006)+I(102)] / I(101).

[0165]

[0166] Experimental Example 2: Evaluation of Electrochemical Properties

[0167] (1) Initial charge capacity (C) 4.7V ), C 4.4V , initial discharge capacity, discharge average voltage evaluation

[0168] After manufacturing the lithium secondary battery half cell, it was aged at 25℃ for 10 hours and then formation was performed at 25℃. At this time, the initial charge capacity (C 4.7V) For evaluation, 200 mAh / g was set as the 1C reference capacity and charging was performed up to 4.7 V with a constant current of 0.1 C. After charging, a rest time of 20 minutes was allowed, and then discharging was performed until 2.5 V was reached with a constant current of 0.1 C with 200 mAh / g as the 1C reference capacity. At this time, the integral value of the discharge voltage according to the capacity was divided by the discharge capacity to calculate the average discharge voltage.

[0169] (2) Life characteristics evaluation (25℃, 50 cycles)

[0170] After manufacturing the lithium secondary battery half cell, it was aged at 25℃ for 10 hours and then formation was performed at 25℃. At this time, the initial charge capacity (C 4.7V ) For evaluation, 200 mAh / g was used as the 1C reference capacity and charging was performed up to 4.7 V with a constant current of 0.1 C. After a rest time of 20 minutes after charging, the battery was discharged until 2.5 V with a constant current of 0.1 C and a 1C reference capacity of 200 mAh / g. From the second cycle, the battery was charged up to 4.5 V with a constant current of 0.5 C and a rest time of 20 minutes. After that, the battery was discharged until 2.5 V with a constant current of 0.5 C. 50 charge / discharge cycles were performed under the same charge / discharge cycle conditions as the second cycle, and the discharge capacity retention rate of the 50th cycle compared to the second cycle was calculated.

[0171] (3) Output characteristics evaluation (2C / 0.2C)

[0172] After manufacturing the lithium secondary battery half cell, the formation was performed at 25℃ after aging for 10 hours. At this time, the initial charge capacity (C 4.7V) For evaluation, 200 mAh / g was set as the 1C reference capacity and charging was performed up to 4.7 V with a constant current of 0.1 C. After a rest time of 20 minutes after charging, discharging was performed up to 2.5 V with a constant current of 0.1 C with a 1C reference capacity of 200 mAh / g. Then, charging was performed up to 4.5 V with a constant current of 0.2 C, and the ratio of the discharge capacity to the discharge capacity until 2.5 V was reached with a constant current of 2 C was measured.

[0173]

[0174] Referring to Tables 1 to 3, in the case of Examples 1 to 3 where the composition of lithium metal oxide and the sintering process conditions such as sintering temperature were appropriately controlled, C 4.4V / C 4.7V It was confirmed that various properties related to the value and X-ray diffraction analysis (c-axis lattice constant, unit cell volume, [A(006)+A(102)] / A(101) peak area ratio) were obtained within the range according to the present invention. In addition, it was confirmed that the life characteristics were significantly improved compared to the comparative example, and that the average discharge voltage was excellent.

[0175] On the other hand, in the case of Comparative Examples 1 to 3, at least one of the contents of nickel, cobalt and manganese or the molar ratio therebetween was not properly controlled, resulting in C 4.4V / C 4.7V It was confirmed that various properties related to the value and X-ray diffraction analysis (c-axis lattice constant, unit cell volume, [A(006)+A(102)] / A(101) peak area ratio) were outside the range according to the present invention. In addition, it was confirmed that the life characteristics were significantly deteriorated compared to the examples, and the average discharge voltage also decreased.

[0176] Comparing examples 1 to 3 in more detail, the firing temperature is higher at C 4.4V / C 4.7VIn the case of Examples 2 and 3, in which the various properties related to the value and X-ray diffraction analysis (c-axis lattice constant, unit cell volume, [A(006)+A(102)] / A(101) peak area ratio) were more appropriately controlled, it was confirmed that the capacity, discharge average voltage, output characteristics, and life characteristics were implemented more preferably compared to Example 1.

[0177]

[0178] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the patent claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

[0179] Accordingly, the actual scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Containing nickel-containing lithium metal oxide with an excess composition of lithium and manganese, A cathode active material for a lithium secondary battery satisfying the following equation 1: [Formula 1] C 4.4V / C 4.7V ≥ 0.55 In the above equation 1, C 4.7V means the full charge capacity during the first charge process with a termination voltage of 4.7 V for lithium metal oxide, and C 4.4V It refers to the charge capacity up to a voltage of 4.4 V during the first charge process with a termination voltage of 4.7 V for lithium metal oxide.

2. In paragraph 1, The above lithium metal oxide is a positive electrode active material for a lithium secondary battery having a molar ratio of lithium to lithium metal oxide of 1.05 to 1.

15.

3. In paragraph 1, The above lithium metal oxide is a positive electrode active material for a lithium secondary battery having a molar ratio of nickel to the total metal excluding lithium of 0.35 to 0.

45.

4. In paragraph 1, The above lithium metal oxide is a positive electrode active material for a lithium secondary battery in which the molar ratio of manganese to the total metal excluding lithium is 0.45 to 0.

63.

5. In paragraph 1, The above lithium metal oxide is a positive electrode active material for a lithium secondary battery, wherein the molar ratio of cobalt to the total metal excluding lithium is 0.01 to 0.

06.

6. In paragraph 1, The above lithium metal oxide is a positive electrode active material for a lithium secondary battery having a molar ratio of nickel to manganese (Ni / Mn) of 0.6 to 0.

85.

7. In paragraph 1, The above lithium metal oxide is a positive electrode active material for a lithium secondary battery having a molar ratio of cobalt to nickel (Co / Ni) of 0.03 to 0.

058.

8. In paragraph 1, The above lithium metal oxide is a positive electrode active material for a lithium secondary battery having a molar ratio of cobalt to manganese (Co / Mn) of 0.032 to 0.

04.

9. In paragraph 1, The above lithium metal oxide is a positive electrode active material for a lithium secondary battery having a c-axis lattice constant of 14.25 to 14.31 Å.

10. In paragraph 1, The lithium metal oxide has a unit cell volume of 102.3 to 103.0 Å. 3 A cathode active material for lithium secondary batteries.

11. In paragraph 1, The above lithium metal oxide is a positive electrode active material for a lithium secondary battery having an [A(006)+A(102)] / A(101) peak area ratio of 0.41 to 0.51 when analyzing an X-ray diffraction pattern.

12. In paragraph 1, The above lithium metal oxide is a positive electrode active material for a lithium secondary battery represented by the following chemical formula 1: [Chemical Formula 1] Li 1+a (Ni x Co y Mr z M w ) 1-a O 2-b A b In the above chemical formula 1, 0.05≤a≤0.15, 0.35≤x≤0.45, 0.01≤y≤0.06, 0.45≤z≤0.63, 0≤w≤0.1, 0≤b≤0.1, x+y+z+w=1, M is Zr, Al, B, Y, Mg, Ti, Nb, W, Sc, Si, V, Fe, Y, Mo, Ce, Hf, Ta, La, Sr, Sn, Sb, Zn, Cu, Ge, Ru, Ir or a combination thereof, and A is PO4, BO3, CO3, NO 3, F, Cl, Br, I or a combination of these.

13. A positive electrode for a lithium secondary battery comprising the positive electrode active material of paragraph 1.

14. A lithium secondary battery comprising the positive electrode for a lithium secondary battery of Article 13.