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

Abstract

The present invention relates to a cathode active material comprising: a lithium metal composite oxide having a lithium- and manganese-rich composition; and a coating layer formed on at least a portion of a surface of the lithium metal composite oxide, wherein the coating layer includes at least three coating elements from among Ti, Zr, Nb, Mo, and W.

Description

Anode active material, method of manufacturing the same, and lithium secondary battery including the same

[0001] The present invention relates to a positive electrode active material, a method for manufacturing the same, and a lithium secondary battery including the same. Specifically, it relates to a positive electrode active material including a high-entropy coating layer, a method for manufacturing the same, and a lithium secondary battery including the same.

[0002] With the recent rapid proliferation of battery-powered electronic devices such as mobile phones, laptop computers, and electric vehicles, the demand for small, lightweight, and relatively high-capacity rechargeable batteries is increasing rapidly. Lithium-ion batteries are gaining prominence as power sources for portable devices due to their lightweight nature and high energy density. Consequently, active research and development efforts are underway to improve the performance of lithium-ion batteries.

[0003] With the recent surge in demand for electric vehicles, there is an increasing need for high-output, high-capacity batteries, leading to a trend of gradually increasing nickel content in cathode active materials. However, while increasing the nickel content in cathode active materials improves initial capacity characteristics, it can lead to reduced thermal stability and increased gas generation due to side reactions with the electrolyte during electrochemical reactions.

[0004] Furthermore, if the nickel content in the cathode active material increases, structural degradation of the active material occurs during charging and discharging, and volume changes within the unit cell increase. These volume changes cause cracks to form within the active material; as charging and discharging are repeated, the formation of these cracks accelerates, leading to defects such as inability to reach the electrolyte or reduced conductivity.

[0005] Accordingly, research on layered cathode active materials with an excess of lithium and manganese composition is actively underway as a candidate for next-generation cathode active materials capable of realizing high-capacity batteries. Unlike cathode active materials with a general composition, cathode active materials with an excess of lithium and manganese composition have the characteristic of utilizing not only transition metals but also redox reactions of anions (oxygen) when operating the battery.

[0006] At this time, while the redox reaction of anions (oxygen) can contribute to high capacity, it has characteristics such as a slower reaction rate compared to the redox reaction of transition metals and a tendency to cause degradation of the crystal structure during operation. As a result, lithium metal oxides with an excess of lithium and manganese may have lower output and lifespan characteristics or voltage drop issues compared to cathode active materials with a standard composition when operating the battery.

[0007] Accordingly, there is a need to develop technology for stabilizing the surface characteristics of the cathode active material in order to improve the problems of reduced output and lifespan characteristics and voltage drop in lithium secondary batteries caused by such anion (oxygen) redox reactions when manufacturing cathode active materials with excess lithium and manganese.

[0008] One objective of the present invention is to provide a positive electrode active material having an excess composition of lithium and manganese with a stabilized surface by including a high-entropy coating layer on the surface of the positive electrode active material.

[0009] Another objective of the present invention is to provide a method for manufacturing a positive electrode active material having an excess composition of lithium and manganese having the aforementioned advantages.

[0010] Another objective of the present invention is to provide a lithium secondary battery with improved rate characteristics, resistance characteristics, and lifespan characteristics, and reduced voltage drop, by using a positive electrode active material comprising a high-entropy coating layer having the aforementioned advantages.

[0011] A positive electrode active material according to one embodiment of the present invention comprises: a lithium metal composite oxide having an excess composition of lithium and manganese; and a high-entropy coating layer formed on at least a portion of the surface of the lithium metal composite oxide; wherein the high-entropy coating layer comprises at least three coating elements among Ti, Zr, Nb, Mo, and W.

[0012] When analyzing the X-ray diffraction (XRD) spectrum of the above positive active material, the ratio of the area of ​​the (003) plane to the area of ​​the (104) plane, the (003) / (104) plane area ratio, may be greater than 0.817 and less than 0.854.

[0013] The content of the above coating element may be less than 5000 ppm based on the total weight of the above positive active material.

[0014] The above coating layer may contain all of the coating elements of Ti, Zr, Nb, Mo, and W.

[0015] The content of Ti among the above coating elements may be 5 to 35 weight percent based on the total weight of the coating elements.

[0016] The content of Zr among the above coating elements may be 5 to 35 weight percent based on the total weight of the coating elements.

[0017] The content of Nb among the above coating elements may be 5 to 35 weight percent based on the total weight of the coating elements.

[0018] The content of Mo among the above coating elements may be 5 to 35 weight percent based on the total weight of the coating elements.

[0019] The content of W among the above coating elements may be 5 to 35 weight percent based on the total weight of the coating elements.

[0020] The above lithium metal composite oxide can be represented by the following chemical formula 1.

[0021] [Chemical Formula 1]

[0022] Li 1+a (Nix Co y Mn z M w ) 1-a O 2-b A b

[0023] In the above Chemical Formula 1, 0 <a≤0.5, 0.2≤x≤0.5, 0≤y≤0.4, 0.5≤z≤0.75, 0≤w≤0.2, 0≤b≤0.1, x+y+z+w=1이고, M은Zr, Al, B, Y, Mg, Ti, Nb, W, Sc, Si, V, Fe, Y, Mo, Ce, Hf, Ta, La, Sr, Sn, Sb, Zn, Cu, Ge, Mo, Ru, Ir 또는 이들의 조합이고, A는 PO4, BO3, CO3, NO3, F, Cl, Br, I 또는 이들의 조합이다.

[0024] A method for manufacturing a positive electrode active material according to another embodiment of the present invention comprises: a step of preparing a nickel and metal composite hydroxide; a step of forming a mixture comprising a metal composite hydroxide and a lithium raw material such that the molar ratio of lithium (Li) to the metal (Me) (Li / Me) is 1 or more; a step of calcining the mixture to form a lithium metal composite oxide; and a step of introducing at least three coating raw materials among a Ti raw material, a Zr raw material, a Nb raw material, a Mo raw material, and a W raw material, and heat-treating to form a coating layer on at least a portion of the surface of the lithium metal composite oxide; wherein, in the step of forming the mixture, the molar ratio of manganese (Mn) to the metal (Me) (Mn / Me) may be 0.5 or more.

[0025] The molar ratio (Li / Me) of lithium (Li) to the metal (Me) may be 1 to 1.5.

[0026] The molar ratio (Mn / Me) of manganese (Mn) to the metal (Me) may be 0.5 to 0.75.

[0027] In the step of forming the above coating layer,

[0028] The method includes the step of forming a coating layer on at least a portion of the surface of the lithium metal composite oxide by introducing a coating raw material comprising all of Ti raw material, Zr raw material, Nb raw material, Mo raw material and W raw material, and the content of one or more raw materials selected from the group consisting of Ti, Zr, Nb, Mo and W can satisfy 5 to 35 weight% with respect to 100 weight% of the total coating raw material.

[0029] The content of the above coating raw material may be less than 5000 ppm based on the total weight of the above anode active material.

[0030] When analyzing the X-ray diffraction (XRD) spectrum of the above positive active material, the ratio of the area of ​​the (003) plane to the area of ​​the (104) plane, the (003) / (104) plane area ratio, may be greater than 0.817 and less than 0.854.

[0031] When calcining the above mixture, the calcination temperature can be performed at a temperature of 700 to 950°C.

[0032] When forming the above coating layer, the heat treatment temperature may be 500 to 800℃.

[0033] A positive electrode according to another embodiment of the present invention comprises the aforementioned positive electrode active material.

[0034] A lithium secondary battery according to another embodiment of the present invention comprises the aforementioned positive electrode, a negative electrode facing the positive electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte.

[0035] A positive electrode active material according to one embodiment of the present invention has the effect of stabilizing the surface of a positive electrode active material by including a high-entropy coating layer on the surface of the positive electrode active material having an excess composition of lithium and manganese.

[0036] A lithium secondary battery according to another embodiment of the present invention includes the aforementioned positive electrode active material, thereby reducing the voltage drop of the lithium secondary battery and improving rate characteristics, resistance characteristics, and lifespan characteristics.

[0037] Figure 1 is the result of measuring the X-ray diffraction spectrum (XRD) of an anode active material including a high-entropy coating layer according to one embodiment of the present invention.

[0038] Figure 2 is the result of measuring the X-ray diffraction spectrum (XRD) of a positive electrode active material according to one comparative example of the present invention.

[0039] In this specification, terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the invention.

[0040] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0041] When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between.

[0042] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0043] Also, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %.

[0044] In this specification, the term “combination(s) of these” described in the Markush-type expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expression, and means including any one or more selected from the group consisting of said components.

[0045] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0046] positive electrode active material

[0047] In this specification, a lithium metal composite oxide of lithium excess composition means that the molar ratio of lithium (Li) to metal (Me) is greater than 1.

[0048] In this specification, a lithium metal composite oxide with a manganese excess composition means that the molar ratio of manganese (Mn) to metal (Me) is 0.5 or higher.

[0049] A positive electrode active material according to one embodiment of the present invention comprises a lithium metal composite oxide having an excess composition of lithium and manganese; and a coating layer formed on at least a portion of the surface of the lithium metal composite oxide, wherein the coating layer comprises at least three coating elements among Ti, Zr, Nb, Mo and W.

[0050] In a positive electrode active material according to one embodiment of the present invention, when analyzing the X-ray diffraction (XRD) spectrum of the positive electrode active material, the ratio of the area of ​​the (003) plane to the area of ​​the (104) plane, the (003) / (104) plane area ratio, may be greater than 0.817 and less than 0.854, specifically 0.820 to 0.852, and more specifically 0.825 to 0.850. When the (003) / (104) plane area ratio satisfies the above range, there may be an advantage in that the formation charge capacity, 0.1C and 0.33C discharge capacity, rate characteristics, life characteristics, initial condition and resistance increase rate, initial average voltage, and voltage drop characteristics of the lithium secondary battery including the positive electrode active material are excellent. On the other hand, if the area ratio of the (003) / (104) planes falls outside the above range, a problem may occur in which the 0.1C discharge capacity and lifespan characteristics of the lithium secondary battery deteriorate.

[0051] In a positive electrode active material according to one embodiment of the present invention, the content of the coating element may be less than 5000 ppm based on the total weight of the positive electrode active material, specifically greater than 0 and less than 5000 ppm, and more specifically 50 to 4500 ppm. When the content of the coating raw material satisfies the above range, excellent electrochemical characteristics of the lithium secondary battery can be realized. On the other hand, if the content of the coating raw material deviates from the above range, a problem may occur in which the electrochemical characteristics of the lithium secondary battery deteriorate.

[0052] In a positive electrode active material according to one embodiment of the present invention, the coating layer may include all of the coating elements of Ti, Zr, Nb, Mo, and W, but is not limited thereto, and any material capable of stabilizing the surface characteristics of the positive electrode active material may be used. When the positive electrode active material includes all of the coating raw materials, the disorder of the surface of the positive electrode active material is increased to an appropriate level to control the expression amount of the anion (oxygen) oxidation-reduction reaction and improve stability, thereby stabilizing the surface of the positive electrode active material, which may have the advantage of improving the output and lifespan characteristics of a lithium secondary battery containing the same.

[0053] In a positive electrode active material according to one embodiment of the present invention, the content of Ti among the coating elements may be 5 to 35 weight% based on 100 weight% of the total coating elements, specifically 10 to 30 weight%, and more specifically 15 to 25 weight%. When the content of Ti satisfies the above range, the disorder of the surface of the positive electrode active material is appropriately controlled, so that not only the discharge capacity but also the Coulomb efficiency can be improved during the cycle process, and manganese (Mn) can be prevented from dissociating and dissolving into the electrolyte even at high cell voltages. On the other hand, if the content of Ti deviates from the above range, the disorder of the surface of the positive electrode active material is not appropriately controlled, so metal is leached by reaction with the electrolyte during the charge and discharge process, and as a result, a metal-deficient layer is formed at the interface, which hinders the movement of lithium ions and electrons, and may cause problems such as difficulty in charging and discharging at high speeds.

[0054] In a positive electrode active material according to one embodiment of the present invention, the content of Zr among the coating elements may be 5 to 35 weight% based on 100 weight% of the total coating elements, specifically 10 to 30 weight%, and more specifically 15 to 25 weight%. When the content of Zr satisfies the above range, the discharge capacity of the lithium secondary battery is not reduced, and since the lithium metal oxide is protected by the Zr coating, there may be an advantage of suppressing the collapse of the charge structure caused by the desorption of lithium ions during charging. On the other hand, if the content of Zr is less than 5 weight%, Zr is not properly coated on the surface of the lithium metal oxide, so the electrolyte reacts with cobalt, causing the cobalt to dissolve into the electrolyte and the crystal structure to collapse. In addition, if the content of Zr exceeds 35 weight%, a problem may occur in which the specific capacity of the lithium secondary battery decreases.

[0055] In a positive electrode active material according to one embodiment of the present invention, the content of Nb among the coating elements may be 5 to 35 weight% based on 100 weight% of the total coating elements, specifically 10 to 30 weight%, and more specifically 15 to 25 weight%. If the content of Nb satisfies the above range, there may be an advantage in preventing the leaching of metal elements within the positive electrode active material and thereby stabilizing the cycle characteristics of the lithium secondary battery. On the other hand, if the content of Nb is less than 5 weight%, the effect of preventing metal leaching and stabilizing cycle characteristics may be negligible. In addition, if the content of Nb exceeds 35 weight%, problems such as reduced capacity and decreased high-temperature stability of the lithium secondary battery may occur.

[0056] In a positive electrode active material according to one embodiment of the present invention, the content of Mo among the coating elements may be 5 to 35 weight% based on 100 weight% of the total coating elements, specifically 10 to 30 weight%, and more specifically 15 to 25 weight%. When the content of Mo satisfies the above range, there may be advantages such as preventing the positive electrode active material from coming into direct contact with the electrolyte and increasing the reactivity of the battery, thereby providing an excellent discharge capacity effect of the lithium secondary battery and increasing its lifespan. On the other hand, if the content of Mo is less than 5 weight%, the effect of preventing metal leaching and stabilizing cycle characteristics may be negligible. In addition, if the content of Mo exceeds 35 weight%, a problem may occur in which the electrochemical characteristics of the lithium secondary battery deteriorate.

[0057] In a positive electrode active material according to one embodiment of the present invention, the content of W among the coating elements may be 5 to 35 weight% based on 100 weight% of the total coating elements, specifically 10 to 30 weight%, and more specifically 15 to 25 weight%. When the content of W satisfies the above range, there may be an advantage of improving the safety of the lithium secondary battery by minimizing structural changes in the positive electrode active material even at high temperatures due to high thermal stability. On the other hand, if the content of W is less than 5 weight%, the improvement effect on the lithium secondary battery due to the formation of the coating layer may be negligible. In addition, if the content of W exceeds 35 weight%, the coating layer becomes excessively thick, which may cause a problem in which output characteristics deteriorate due to increased resistance.

[0058] In a positive electrode active material according to one embodiment of the present invention, the lithium metal composite oxide can be represented by the following chemical formula 1.

[0059] [Chemical Formula 1]

[0060] Li 1+a (Ni x Co y Mn z M w ) 1-a O 2-b A b

[0061] In the above Chemical Formula 1, 0 <a≤0.5, 0.2≤x≤0.5, 0≤y≤0.4, 0.5≤z≤0.75, 0≤w≤0.2, 0≤b≤0.1, x+y+z+w=1이고, M은Zr, Al, B, Y, Mg, Ti, Nb, W, Sc, Si, V, Fe, Y, Mo, Ce, Hf, Ta, La, Sr, Sn, Sb, Zn, Cu, Ge, Mo, Ru, Ir 또는 이들의 조합이고, A는 PO4, BO3, CO3, NO3, F, Cl, Br, I 또는 이들의 조합이다.

[0062] In the lithium metal oxide of Chemical Formula 1 above, wherein a is 0 in the moles of lithium (Li) 1+a. <a≤0.5일 수 있고 구체적으로 0.05≤a≤0.4일 수 있다. a가 상기 범위를 만족할 경우 리튬(Li)이 과잉임에 따라 용량 특성이 향상될 수 있다. 다만, a가 상기 범위를 벗어날 경우 상안정성 저하로 인해 수명 특성이 열화 될 수 있다.

[0063] In the lithium metal oxide of Chemical Formula 1 above, if the moles of nickel (Ni) x are less than 0.2, the amount of oxygen oxidation / reduction reaction increases too much, and a problem may occur in which the lifespan characteristics deteriorate. In addition, if the moles of nickel (Ni) x are greater than 0.5, the amount of oxygen oxidation / reduction reaction decreases, and a problem may occur in which the capacity and output characteristics deteriorate.

[0064] In the lithium metal oxide of the above chemical formula 1, if the number of moles y of cobalt (Co) falls outside the above range, it may be difficult to simultaneously achieve sufficient rate characteristics and high powder density of the active material, and problems may arise such as an overall increase in the cost of raw materials and a decrease in reversible capacity.

[0065] In the lithium metal oxide of Chemical Formula 1 above, if the number of moles of manganese (Mn) z is less than 0.5, the production cost may increase, the stability of the active material may decrease, and problems such as capacity degradation may occur. If the number of moles of manganese (Mn) z is greater than 0.75, problems such as reduced lifespan characteristics due to excessive use of oxygen oxidation / reduction reactions and manganese leaching may occur.

[0066]

[0067] Method for manufacturing positive electrode active material

[0068] A method for manufacturing a positive electrode active material according to another embodiment of the present invention comprises the steps of: preparing a nickel and metal composite hydroxide; forming a mixture comprising a metal composite hydroxide and a lithium raw material such that the molar ratio of lithium (Li) to the metal (Me) (Li / Me) is 1 or more; calcining the mixture to form a lithium metal composite oxide; and introducing at least three coating raw materials among a Ti raw material, a Zr raw material, a Nb raw material, a Mo raw material, and a W raw material, and heat treating to form a coating layer on at least a portion of the surface of the lithium metal composite oxide, wherein in the step of forming the mixture, the molar ratio of manganese (Mn) to the metal (Me) (Mn / Me) is 0.5 or more.

[0069] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the molar ratio (Li / Me) of lithium (Li) to the metal (Me) may be 1.0 to 1.5, specifically 1.1 to 1.4. When the molar ratio of lithium (Li) to the metal (Me) satisfies the above range, the capacity characteristics of the battery may be excellent. On the other hand, if the molar ratio of lithium (Li) to the metal (Me) exceeds 1.5, a problem of phase stability may arise due to the excessive occurrence of oxidation-reduction reactions of oxygen, and as a result, the lifespan characteristics may be degraded.

[0070] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the molar ratio (Mn / Me) of manganese (Mn) to the metal (Me) may be 0.5 to 0.75, specifically 0.525 to 0.7, and more specifically 0.55 to 0.65. If the molar ratio of manganese (Mn) to the metal (Me) is less than 0.5, problems may arise such as increased manufacturing costs and reduced safety of the positive electrode active material. On the other hand, if the molar ratio of manganese (Mn) to the metal (Me) exceeds 0.75, problems may arise such as reduced lifespan characteristics and leaching of manganese due to excessive use of oxygen in oxidation-reduction reactions.

[0071] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the molar ratio (Ni / Me) of nickel (Ni) to metal (Me) in the lithium metal oxide may be 0.2 to 0.5. When the molar ratio of nickel (Ni) to the metal (Me) satisfies the above range, there may be an advantage in that the capacity, output, and lifespan characteristics of the battery become excellent. On the other hand, if the molar ratio of nickel (Ni) to the metal (Me) is less than 0.2, the amount of anion (oxygen) oxidation-reduction reaction increases too much, and a problem may occur in which lifespan characteristics deteriorate. In addition, if the molar ratio of nickel (Ni) to the metal (Me) is greater than 0.5, the amount of anion (oxygen) oxidation-reduction reaction decreases, and a problem may occur in which the capacity and output characteristics of the battery deteriorate.

[0072] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the lithium metal oxide may not contain cobalt. Conventional high-nickel NCM positive electrode materials contain a high nickel content, which degrades the structural stability of the active material and consequently reduces the battery's lifespan and safety; to compensate for this, expensive cobalt was included. However, in the present invention, by reducing the nickel content in the lithium metal oxide and incorporating an excess of manganese to improve structural stability, the problem of battery lifespan and safety degradation can be improved even without including expensive cobalt.

[0073] A method for manufacturing a positive electrode active material according to another embodiment of the present invention comprises, in the step of forming the coating layer, a coating raw material including all of Ti raw material, Zr raw material, Nb raw material, Mo raw material, and W raw material, and forming a coating layer on at least a portion of the surface of the lithium metal composite oxide, wherein the content of one or more raw materials selected from the group consisting of Ti, Zr, Nb, Mo, and W can satisfy 5 to 35 weight% with respect to 100 weight% of the total coating raw material. When the coating raw material in the coating layer includes all of Ti raw material, Zr raw material, Nb raw material, Mo raw material, and W raw material, the disorder of the surface of the positive electrode active material is increased to an appropriate level to control the expression amount of anion (oxygen) oxidation-reduction reaction and improve stability, thereby stabilizing the surface of the positive electrode active material and providing the advantage of improving the output and lifespan characteristics of a lithium secondary battery containing the same.

[0074] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the content of the Ti raw material among the total content of the coating raw material including all of Ti, Zr, Nb, Mo, and W may be 5 to 35 weight%, specifically 10 to 30 weight%, and more specifically 15 to 25 weight%. When the content of the Ti raw material satisfies the above range, Ti is properly coated on the surface of the positive electrode active material, so that not only the discharge capacity but also the Coulomb efficiency can be improved during the cycle process, and manganese (Mn) and lithium (Li) can be prevented from dissociating and dissolving into the electrolyte even at high cell voltages. On the other hand, if the content of the Ti raw material falls outside the above range, titanium oxide is not properly coated on the surface of the positive electrode active material, so metal is leached by reaction with the electrolyte during the charge and discharge process, and as a result, a metal-deficient layer is formed at the interface, which hinders the movement of lithium ions and electrons, and may cause problems such as difficulty in charging and discharging at high speeds.

[0075] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the content of the Zr raw material among the total content of the coating raw material including all of Ti, Zr, Nb, Mo, and W may be 5 to 35 weight%, specifically 10 to 30 weight%, and more specifically 15 to 25 weight%. When the content of the Zr raw material satisfies the above range, the lithium metal oxide is protected by the Zr coating without reducing the discharge capacity of the lithium secondary battery, so there may be an advantage in suppressing the collapse of the charge structure caused by the desorption of lithium ions during charging. On the other hand, if the content of the Zr raw material is less than 5 weight%, Zr is not properly coated on the surface of the lithium metal oxide, so the electrolyte reacts with cobalt, causing the cobalt to dissolve into the electrolyte and the crystal structure to collapse. In addition, if the content of the Zr raw material exceeds 35 weight%, a problem may occur in which the specific capacity of the lithium secondary battery decreases.

[0076] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the content of the Nb raw material among the total content of the coating raw material including all of Ti, Zr, Nb, Mo, and W may be 5 to 35 weight%, specifically 10 to 30 weight%, and more specifically 15 to 25 weight%. If the content of the Nb raw material satisfies the above range, there may be an advantage of preventing the leaching of metal elements within the positive electrode active material and thereby stabilizing the cycle characteristics of the lithium secondary battery. On the other hand, if the content of the Nb raw material is less than 5 weight%, the effect of preventing metal leaching and stabilizing cycle characteristics may be negligible. In addition, if the content of the Nb raw material exceeds 35 weight%, problems such as reduced capacity and decreased high-temperature stability of the lithium secondary battery may occur.

[0077] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the content of the Mo raw material in the total content of the coating raw material containing all of Ti, Zr, Nb, Mo, and W may be 5 to 35 weight%, specifically 10 to 30 weight%, and more specifically 15 to 25 weight%. When the content of the Mo raw material satisfies the above range, it prevents the positive electrode active material from coming into direct contact with the electrolyte and increases the reactivity of the battery, thereby providing the advantage of an excellent discharge capacity effect of the lithium secondary battery and an increased lifespan. On the other hand, if the content of the Mo raw material is less than 5 weight%, the effect of preventing metal leaching and stabilizing cycle characteristics may be negligible. Furthermore, if the content of the Mo raw material exceeds 35 weight%, the excessive inclusion of Mo may reduce the uniformity of the coating layer and lead to structural instability.

[0078] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the content of the W raw material among the total content of the coating raw material including all of Ti, Zr, Nb, Mo, and W may be 5 to 35 weight%, specifically 10 to 30 weight%, and more specifically 15 to 25 weight%. When the content of W satisfies the above range, there may be an advantage of improving the safety of the lithium secondary battery by minimizing structural changes in the positive electrode active material even at high temperatures due to high thermal stability. On the other hand, if the content of W is less than 5 weight%, the improvement effect on the lithium secondary battery due to the formation of the coating layer may be negligible. In addition, if the content of W exceeds 35 weight%, the coating layer becomes excessively thick, which may cause a problem in which output characteristics deteriorate due to increased resistance.

[0079] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the content of the coating raw material may be less than 5000 ppm based on the total weight of the positive electrode active material, specifically greater than 0 ppm and less than 5000 ppm, and more specifically 50 to 4500 ppm. When the content of the coating raw material satisfies the above range, excellent electrochemical characteristics of the lithium secondary battery can be realized. On the other hand, if the content of the coating raw material deviates from the above range, a problem may occur in which the electrochemical characteristics of the lithium secondary battery deteriorate.

[0080] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, when analyzing the X-ray diffraction (XRD) spectrum of the positive electrode active material, the ratio of the area of ​​the (003) plane to the area of ​​the (104) plane, the (003) / (104) plane area ratio, may be greater than 0.817 and less than 0.854, specifically 0.820 to 0.852, and more specifically 0.825 to 0.850. When the (003) / (104) plane area ratio satisfies the above range, there may be an advantage in that the formation charge capacity, 0.1C and 0.33C discharge capacity, rate characteristics, life characteristics, initial condition and resistance increase rate, initial average voltage, and voltage drop characteristics of the lithium secondary battery containing the positive electrode active material are excellent. On the other hand, if the area ratio of the (003) / (104) planes falls outside the above range, a problem may occur in which the 0.1C discharge capacity and lifespan characteristics of the lithium secondary battery deteriorate.

[0081] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the calcination temperature during the calcination of the mixture can be performed at a temperature of 700 to 950°C, specifically at a temperature of 750 to 900°C, and more specifically at a temperature of 800 to 850°C. When the calcination temperature satisfies the above range, a lithium metal oxide with an excess composition of lithium and manganese can be manufactured. On the other hand, if the calcination temperature deviates from the above range, the phase formation may be too insufficient or too excessive, which may result in a problem of reduced capacity of the lithium secondary battery.

[0082] In a method for manufacturing a positive electrode active material according to another embodiment of the present invention, the heat treatment temperature when forming the coating layer may be 500 to 800°C, specifically 550 to 750°C, and more specifically 600 to 700°C. When the heat treatment temperature satisfies the above range, a high-entropy coating layer is properly formed on the surface of the positive electrode active material, which has the advantage of improving the electrochemical characteristics of the lithium secondary battery. On the other hand, if the heat treatment temperature deviates from the above range, the coating layer is incompletely formed on the surface of the positive electrode active material, and the amount of anion (oxygen) oxidation-reduction reaction increases or decreases too much, which may cause a problem in which the lifespan characteristics of the lithium secondary battery deteriorate.

[0083]

[0084] lithium secondary battery

[0085] A lithium secondary battery according to another embodiment of the present invention provides a lithium secondary battery comprising a positive electrode for a lithium secondary battery as described above.

[0086] A lithium secondary battery may further include a separator located between the aforementioned positive electrode for a lithium secondary battery and a lithium metal negative electrode, and may have an electrolyte impregnated in the separator. This structure may be formed by following a method generally known in the industry, using the aforementioned positive electrode for a lithium metal secondary battery and lithium metal, manufacturing an electrode assembly by placing a separator between them, embedding the electrode assembly in a battery case, and injecting an electrolyte into the separator.

[0087] Activation can be performed by discharging and charging while the lithium metal negative electrode is sufficiently wet with the electrolyte injected into the separator.

[0088] Meanwhile, in the lithium metal secondary battery of the above embodiment, the positive coating layer and components other than the positive electrode including it may be adopted as those generally known in the industry.

[0089] The above lithium metal negative electrode can be manufactured by depositing lithium metal on one or both sides of a planar negative current collector or by rolling a lithium foil. In this case, the negative current collector may be, in detail, a copper foil.

[0090] The copper foil can generally be made with a thickness of 3 to 100 micrometers, and the metallic lithium formed on this copper foil can be formed with a thickness of, for example, 1 to 300 micrometers. Alternatively, a negative electrode consisting only of lithium metal may be used.

[0091] The above 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 0.01 to 10 micrometers, and the thickness is generally 5 to 300 micrometers. For example, olefin-based polymers such as chemically resistant and hydrophobic polypropylene; sheets or nonwoven fabrics made of glass fibers or polyethylene are used as such separators. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as the separator.

[0092] The above electrode assembly is not limited in its structure and may be a stacked electrode assembly in which an anode, a separator, and a cathode are stamped out as unit electrodes and stacked, a jelly-roll type electrode assembly in which an anode sheet, a separator, and a cathode sheet are stacked and wound, or a stack-and-fold type electrode assembly in which unit electrodes are arranged on a separator film on a sheet and wound.

[0093] The above battery case may be a pouch-type battery case made of an aluminum laminate sheet, or a rectangular or cylindrical battery case made of a metal can.

[0094] The above electrolyte may include organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, molten inorganic electrolytes, etc., which can be used in the manufacture of lithium secondary batteries, but is not limited to these.

[0095] Specifically, the above organic liquid electrolyte, i.e., the electrolyte, may include an organic solvent and a lithium salt.

[0096] The above organic solvent may be used without special restrictions as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move.Specifically, the above organic solvents include ester-based solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether-based solvents such as dibutyl ether or tetrahydrofuran; ketone-based solvents such as cyclohexanone; aromatic hydrocarbon-based solvents such as benzene and fluorobenzene; and carbonate-based solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), methylethyl carbonate (MEC), ethylmethyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC). Ether-based solvents such as dimethoxyethane (DME), diethyl ether, ethylene glycol dimethyl ether (EGDME), and tetraethylene glycol dimethyl ether (TEGDME); dioxolanes such as 1,3-dioxolane (DOL); furans such as tetrahydrofuran (THF) and 2-methyltetrahydrofuran (2MeTHF); alcohol-based solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R is a straight-chain, branched, or cyclic hydrocarbon group having C2 to C20 structures and may include a double bond, a directional ring, or an ether bond); amides such as dimethylformamide; or sulfolanes may be used.Among these, carbonate-based solvents or ether-based solvents are preferred, 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 low-viscosity linear carbonate-based compound (e.g., ethylmethyl carbonate, dimethyl carbonate or diethyl carbonate, etc.) is more preferred. In this case, using a mixture of the cyclic carbonate and the chain carbonate in a volume ratio of about 1:1 to about 1:9 can result in excellent performance of the electrolyte. A mixture of a linear ether (e.g., dimethoxy ether, ethylene glycol dimethyl ether, etc.) with excellent reduction stability that can improve the reversible charge / discharge performance of lithium metal and a cyclic dioxolane may also be used.

[0097] The above lithium salt can be used without special restrictions as long as it is a compound capable of providing lithium ions used in lithium secondary batteries. Specifically, the lithium salt may be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2. The concentration of the lithium salt may be within the range of 0.1M to 2.0M or within the range of 2.0M to 6.0M. When the concentration of the lithium salt is within the range of 0.1M to 2.0M, the electrolyte has appropriate conductivity and viscosity, so it can exhibit excellent electrolyte performance and lithium ions can move effectively. When the concentration of the lithium salt is in the range of 2.0M to 6.0M, the transfer number of lithium increases, allowing lithium ions to move effectively, and all of the electrolyte solvent coordinates to the lithium salt, thereby improving the oxidation and reduction stability of the electrolyte solvent and suppressing corrosion of the lithium metal and current collector.

[0098] In addition to the above electrolyte components, the above electrolyte may further include one or more additives for the purpose of improving the lifespan characteristics of the battery, suppressing the decrease in battery capacity, and improving the discharge capacity of the battery, such as, for example, a haloalkylene carbonate-based compound such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, triamide hexaphosphate, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, or aluminum trichloride.

[0099] However, the above contents are merely examples of components and methods generally known in the industry, and can be modified at any time according to the technical common sense of those skilled in the art.

[0100] The lithium metal secondary battery of the above embodiment may also be provided as a battery module including the same as a unit cell and as a battery pack including the same.

[0101] The above battery module or battery pack can be used as a power source for one or more medium-to-large devices, including a power tool; an electric vehicle (EV), a hybrid electric vehicle, and a plug-in hybrid electric vehicle (PHEV); or a power storage system.

[0102] The embodiments of the present invention will be described in more detail below through examples. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited by the following examples.

[0103] Example 1

[0104] 1-1. Preparation of Cathode Active Material

[0105] (Preparation of transition metal hydroxide) Secondary particle transition metal hydroxide of composition Ni(0.35)Co(0)Mn(0.65)(OH)2 was prepared through a conventional co-precipitation process.

[0106] After (calcination), LiOH·H2O was mixed in the kiln with the transition metal precursor so that the molar ratio (Li / M) of lithium (Li) to the transition metal (M) in the transition metal precursor was (1.33), and then the temperature was gradually increased and calcined at a temperature of 850°C for 10 hours under an atmospheric atmosphere to produce a lithium transition metal oxide with the composition Li(1.142)Ni(0.3)Co(0)Mn(0.558)O2.

[0107] After (discharge), the above lithium transition metal oxide was discharged by natural cooling.

[0108] After (coating), TiO2, ZrO2, Nb2O5, MoO3, and WO3 were mixed to be added at a concentration of 1000 ppm based on the total weight of the lithium metal oxide, and then coated by heat treatment at a temperature of 700 ℃ for 5 hours in an atmospheric environment. At this time, the weight ratio of the transition metal elements of the added TiO2, ZrO2, Nb2O5, MoO3, and WO3 was set to 1:1:1:1:1.

[0109] 1-2. Lithium Secondary Battery Manufacturing

[0110] The slurry for manufacturing the electrode plate was prepared by mixing the above-prepared positive active material:conductive material (carbon black, Denka black):binder (PVDF, KF1100) in a ratio of 92.5:3.5:4 wt%, and adding NMP (N-Methyl-2-pyrrolidone) to adjust the viscosity so that the solid content was about 30%.

[0111] The prepared slurry was coated onto a 15 µm thick Al foil using a doctor blade and then dry-rolled. The electrode loading was 14.6 mg / cm², and the rolling density (25℃, 20 kN) was 3.1 g / cm². 3The electrolyte used was 1M LiPF6 in EC:DMC:EMC=3:4:3 (vol%) with 3.0 vol% of VC added relative to the total amount of the electrolyte, and a coin cell was manufactured using a PP separator and a lithium anode (200 μm, Honzo metal).

[0112] Example 2

[0113] A positive electrode active material and a lithium secondary battery were prepared in the same manner as in Example 1, except that in the coating step, the input amounts of TiO2, ZrO2, Nb2O5, MoO3, and WO3 were adjusted so that 3000 ppm of high-entropy transition metal elements were added based on the total weight of the lithium metal oxide.

[0114] Comparative Example 1

[0115] A positive electrode active material and a lithium secondary battery were prepared in the same manner as in Example 1, except that the coating step was not performed.

[0116] Comparative Example 2

[0117] A positive electrode active material and a lithium secondary battery were prepared in the same manner as in Example 1, except that in the coating step, the input amounts of TiO2, ZrO2, Nb2O5, MoO3, and WO3 were adjusted so that 5000 ppm of high-entropy transition metal elements were added based on the total weight of the lithium metal oxide.

[0118] Experimental Example 1 Evaluation of Physical Properties of Anode Active Material

[0119] X-ray diffraction analysis was performed on the cathode active material according to one embodiment and comparative example of the present invention using an X-ray diffraction analysis device (Malvern Panalytical X'Pert3 Powder) Cu Kα radiation (λ Kα1 = 1.540598Å, * λ Kα2 = 1.544426Å), and the results are shown in Table 1, Figures 1 and 2.

[0120] Referring to FIGS. 1 and 2, the X-ray diffraction (XRD) measurement results of the positive electrode active material according to one embodiment and a comparative example of the present invention can be confirmed. Specifically, it can be confirmed that (003) / (104) of Example 1 in FIG. 1 is 0.839, and (003) / (104) of Example 2 is 0.831. In addition, it can be confirmed that (003) / (104) of Comparative Example 1 in FIG. 2 is 0.854, and (003) / (104) of Comparative Example 2 is 0.817.

[0121] Experimental Example 2: Evaluation of Electrochemical Characteristics of a Lithium Secondary Battery

[0122] (Formation Capacity and Efficiency Evaluation) After fabricating lithium secondary battery half cells, they were aged at 45°C for 12 hours, and then a charge-discharge test was conducted at 45°C. To evaluate the formation capacity and efficiency, the reference capacity was set to 200 mAh / g, and the cells were charged to 4.65V with a constant current of 0.1C. Then, the voltage was switched to a constant voltage, and charging continued until the terminal current reached 0.05C. After a rest time of 20 minutes following charging, the cells were discharged to 2.0V with a constant current of 0.1C and a reference capacity of 200 mAh / g, and the results are shown in Table 2.

[0123] (Evaluation of 0.1C and 0.33C Discharge Capacity and Rate Characteristics) To evaluate the 0.1C and 0.33C discharge capacities, charge-discharge tests were conducted at 25°C on the cells that had undergone the initial capacity evaluation described above. For the 0.1C discharge capacity evaluation, 200 mAh / g was used as the reference capacity, and the cells were charged to 4.4V using a constant current of 0.1C; then, the voltage was switched to a constant voltage, and charging continued until the terminal current reached 0.05C. After a rest time of 20 minutes following charging, the cells were discharged until they reached 2.5V using a constant current of 0.1C with a reference capacity of 200 mAh / g. For the 0.33C discharge capacity evaluation, charge-discharge tests were conducted under the same conditions as above, except that a constant current of 0.33C was used. To evaluate the rate characteristics, the 0.1C discharge capacity and the 0.33C discharge capacity were compared, and the results are shown in Table 2.

[0124] (Evaluation of life characteristics) The life characteristics were evaluated by performing 50 charge-discharge cycles under the above 0.33C discharge capacity evaluation conditions, and the results are shown in Table 2.

[0125] (Initial Resistance and Resistance Growth Rate) Under the above 0.33 C discharge capacity evaluation conditions, 50 charge-discharge cycles were performed to evaluate the initial resistance and resistance growth rate, and the results are shown in Table 2. The initial resistance was evaluated by measuring the impedance 1 minute after the start of the first 0.33 C cycle discharge, and the resistance growth rate was evaluated by comparing the resistance obtained by measuring the impedance 1 minute after the start of the 50th 0.33 C discharge with the initial resistance.

[0126] (Initial average voltage and voltage drop) Under the above 0.33 C discharge capacity evaluation conditions, 50 charge-discharge cycles were performed to evaluate the initial average voltage and voltage drop, and the results are shown in Table 2. The initial average voltage was evaluated by measuring the average voltage during discharge of the first 0.33 C cycle, and the voltage drop was evaluated by measuring the average voltage during discharge of the 50th 0.33 C cycle and comparing it with the average voltage during discharge of the first 0.33 C cycle.

[0127] XRD (003) / (104) Area Non-Example 10.839 Example 20.831 Comparative Example 10.854 Comparative Example 20.817

[0128] Referring to Table 1, in the case of Examples 1 and 2, where the content of the high-entropy coating raw material was appropriately controlled to the range according to the present invention, it was confirmed that the physical properties of the cathode active material, including the (003) / (104) area ratio, satisfied the range according to the present invention. On the other hand, in the case of Comparative Examples 1 or 2, where the coating layer was absent or the coating raw material was contained in excessive amounts, it was confirmed during XRD analysis that the physical properties of the active material, including the (003) / (104) area ratio, fell outside the range according to the present invention.

[0129] Battery Electrochemical Characteristics Comparison Example 1 Example 1 Example 2 Comparison Example 2 Formation Capacity and Efficiency 0.1C Charge Capacity (mAh / g) 281.8 273.9 270.1 268.6 0.1 C Discharge Capacity (mAh / g) 260.2 254.5 250.8 249.6 Efficiency (%) 92.3 92.9 92.8 92.9 0.1 C Discharge Capacity (mAh / g) 205.3 204.6 204.1 201.4 0.3 C Discharge Capacity (mAh / g) 188.2 191.0 191.6 190.1 0.3 C / 0.1C Rate Characteristics (%) 91.7 93.4 93.9 94.4 50 Cycle Life Characteristics (%) 96.1 97.9 97.3 96.1 Initial Resistance (Ω) 36.7 32.4 30.5 29.0 50-cycle resistance growth rate (%) 50.0 4 3.2 4 1.4 38.7 Initial average voltage (V) 3.7 0 52 3.7 14 1 3.7 18 6 3.7 14 5 50-cycle voltage drop (mV) 57.3 5 4.4 5 4.9 5 2.9

[0130] Referring to Table 2, it can be confirmed that Comparative Example 1, which does not include a high-entropy coating layer, has inferior battery electrochemical characteristics compared to Examples 1 and 2, which include a high-entropy coating layer. Through this, it can be confirmed that Comparative Example 1, which does not include a coating layer on the positive electrode active material, has a higher initial resistance compared to Examples 1 and 2, and consequently, as the cycle progresses, the resistance increase rate at 50 cycles increases, resulting in inferior 50-cycle lifespan characteristics compared to Examples 1 and 2. Furthermore, while the initial resistance, resistance increase rate at 50 cycles, and voltage drop at 50 cycles of Comparative Example 2 appear to be equivalent to or superior to Examples 1 and 2, it can be confirmed that the long-term 50-cycle lifespan characteristics are significantly inferior compared to the examples. This may imply that when metal elements are introduced in excess during the high-entropy coating of the positive electrode active material, the metal elements remaining uncoated on the positive electrode active material act as impurities, causing the long-term lifespan characteristics to become significantly inferior compared to the examples. On the other hand, it can be confirmed that Examples 1 and 2 have superior electrochemical properties compared to Comparative Examples 1 and 2. Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto and can be implemented with various modifications within the scope of the claims, the detailed description of the invention, and the attached drawings, and it is obvious that such modifications also fall within the scope of the present invention.

[0131] Therefore, the substantive scope of the present invention shall be defined by the appended claims and their equivalents.

Claims

1. A lithium metal composite oxide with an excess composition of lithium and manganese; and A high-entropy coating layer formed on at least a portion of the surface of the lithium metal composite oxide; comprising The above high-entropy coating layer comprises at least three coating elements among Ti, Zr, Nb, Mo, and W, forming an anode active material.

2. In Paragraph 1, A positive active material in which, when analyzing the X-ray diffraction (XRD) spectrum of the above positive active material, the ratio of the area of ​​the (003) plane to the area of ​​the (104) plane (003) / (104) plane area ratio is greater than 0.817 and less than 0.

854.

3. In Paragraph 1, A positive electrode active material having a coating element content of less than 5000 ppm based on the total weight of the positive electrode active material.

4. In Paragraph 1, The above coating layer is a positive active material comprising all coating elements of Ti, Zr, Nb, Mo, and W.

5. In Paragraph 1, A positive electrode active material in which the content of Ti among the above coating elements is 5 to 35 weight% based on 100 weight% of the total coating elements.

6. In Paragraph 1, A positive electrode active material in which the content of Zr among the above coating elements is 5 to 35 weight% based on 100 weight% of the total coating elements.

7. In Paragraph 1, A positive electrode active material in which the content of Nb among the above coating elements is 5 to 35 weight% based on 100 weight% of the total coating elements.

8. In Paragraph 1, A positive electrode active material in which the content of Mo among the above coating elements is 5 to 35 weight% based on 100 weight% of the total coating elements.

9. In Paragraph 1, A positive electrode active material in which the content of W among the above coating elements is 5 to 35 weight% based on 100 weight% of the total coating elements.

10. In Paragraph 1, The above lithium metal composite oxide is a positive active material 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 <a≤0.5, 0.2≤x≤0.5, 0≤y≤0.4, 0.5≤z≤0.75, 0≤w≤0.2, 0≤b≤0.1, x+y+z+w=1이고, M은Zr, Al, B, Y, Mg, Ti, Nb, W, Sc, Si, V, Fe, Y, Mo, Ce, Hf, Ta, La, Sr, Sn, Sb, Zn, Cu, Ge, Mo, Ru, Ir 또는 이들의 조합이고, A는 PO4, BO3, CO3, NO3, F, Cl, Br, I 또는 이들의 조합이다.

11. Step of preparing nickel and metal complex hydroxide; A step of forming a mixture comprising a metal composite hydroxide and a lithium raw material such that the molar ratio (Li / Me) of lithium (Li) to the metal (Me) is 1 or more; A step of forming a lithium metal composite oxide by calcining the above mixture; and The method comprises the step of forming a coating layer on at least a portion of the surface of the lithium metal composite oxide by introducing at least three coating raw materials among Ti raw material, Zr raw material, Nb raw material, Mo raw material, and W raw material, and heat treating. A method for manufacturing an anode active material, wherein in the step of forming the above mixture, the molar ratio (Mn / Me) of manganese (Mn) to the metal (Me) is 0.5 or higher.

12. In Paragraph 11, A method for manufacturing a positive electrode active material, wherein the molar ratio (Li / Me) of lithium (Li) to the metal (Me) is 1 to 1.

5.

13. In Paragraph 11, A method for manufacturing an anode active material, wherein the molar ratio (Mn / Me) of manganese (Mn) to the metal (Me) is 0.5 to 0.

75.

14. In Paragraph 11, In the step of forming the above coating layer, The method includes the step of forming a coating layer on at least a portion of the surface of the lithium metal composite oxide by introducing a coating raw material comprising all of the Ti raw material, Zr raw material, Nb raw material, Mo raw material, and W raw material. A method for manufacturing an anode active material, wherein the content of one or more raw materials selected from the group consisting of Ti, Zr, Nb, Mo, and W is 5 to 35 weight% with respect to 100 weight% of the total coating raw material.

15. In Paragraph 11, A method for manufacturing a positive electrode active material, wherein the content of the coating raw material is less than 5000 ppm based on the total weight of the positive electrode active material.

16. In Paragraph 11, A method for manufacturing a positive electrode active material, wherein the ratio of the area of ​​the (003) plane to the area of ​​the (104) plane when analyzing the X-ray diffraction spectrum (XRD) of the positive electrode active material is greater than 0.817 and less than 0.

854.

17. In Paragraph 11, A method for manufacturing an anode active material, wherein the calcination temperature during the calcination of the above mixture is performed at a temperature of 700 to 950℃.

18. In Paragraph 11, A method for manufacturing an anode active material, wherein the heat treatment temperature when forming the coating layer is 500 to 800℃.

19. A positive electrode comprising a positive electrode active material according to any one of claims 1 to 10.

20. Anode pursuant to Paragraph 19; A cathode opposite to the anode above; A separator disposed between the anode and the cathode; and A lithium secondary battery comprising an electrolyte.

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