Metal salt for positive electrode active material precursor, manufacturing method therefor, positive electrode active material precursor, positive electrode active material, positive electrode, and lithium secondary battery

Abstract

The present invention relates to: a metal salt for a positive electrode active material precursor, which comprises a compound represented by chemical formula 1 and is in the form of a non-spherical secondary particle solid solution in which nickel and manganese are homogeneously distributed to form a single phase; a preparation method therefor; a positive electrode active material precursor comprising a sintered material of the metal salt for a positive electrode active material precursor; a positive electrode active material comprising a lithium composite transition metal oxide, which is a sintered material of the positive electrode active material precursor and a lithium raw material; a positive electrode comprising the positive electrode active material; and a lithium secondary battery.

Description

Metal salt for a positive electrode active material precursor, method for manufacturing the same, positive electrode active material precursor, positive electrode active material, positive electrode and lithium secondary battery

[0001] The present application claims the benefit of priority based on Korean Patent Application No. 10-2024-0195477 filed December 24, 2024 and Korean Patent Application No. 10-2025-0207074 filed December 22, 2025, the entire contents of which are incorporated herein.

[0002] The present invention relates to a metal salt for a positive electrode active material precursor, which is a nickel-manganese composite metal salt compound, a method for manufacturing the same, a positive electrode active material precursor manufactured using the metal salt, a positive electrode active material manufactured using the positive electrode active material precursor, and a positive electrode and a lithium secondary battery comprising the positive electrode active material.

[0003] Lithium-ion batteries produce electrical energy through oxidation and reduction reactions when lithium ions are inserted into and extracted from the positive and negative electrodes. The positive electrode active material, one of the core components of a lithium-ion battery, directly affects the battery's performance, lifespan, and stability.

[0004] Conventionally, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, and lithium iron phosphate compounds have been primarily used as cathode active materials for lithium secondary batteries. However, with the development of lithium composite transition metal oxides in which a portion of nickel is replaced with other metals such as manganese to improve the low thermal stability while maintaining the excellent reversible capacity of lithium nickel oxide, efforts to improve the performance of lithium secondary batteries utilizing these oxides have recently been ongoing.

[0005] To manufacture lithium composite transition metal oxides, it is important to first form a precursor in which metal ions are uniformly mixed, and one of the widely used methods for this process is the coprecipitation method. Coprecipitation is a reaction in which metal ions chemically react in an aqueous solution and precipitate in a solid form. For example, metal ions such as nickel and manganese are precipitated by coprecipitation as precursors in the form of mixed metal oxides or hydroxides.

[0006] Although the coprecipitation method allows for the uniform mixing of various metal ions to obtain a precursor of a desired composition, a drawback is that it requires significant time and cost due to the multi-step chemical reactions, washing, and filtration processes involved.

[0007] Therefore, there is a need to develop a new precursor manufacturing method to solve these problems of the coprecipitation method.

[0008] The present invention aims to provide a metal salt for a positive electrode active material precursor capable of solving the aforementioned problems and a method for manufacturing the same, a positive electrode active material precursor manufactured using the metal salt, a positive electrode active material manufactured using the precursor, and a positive electrode and a lithium secondary battery comprising the positive electrode active material.

[0009] [1] The present invention provides a metal salt for a positive electrode active material precursor comprising a compound represented by the following chemical formula 1, in the form of a non-spherical secondary particle solid solution in which nickel and manganese are homogeneously distributed to form a single phase.

[0010] [Chemical Formula 1]

[0011] (Ni a Mn b M 1 c )X

[0012] In the above chemical formula 1,

[0013] M 1is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0014] X is SO4 or (NO3)2, and

[0015] a, b, and c are each 0 <a<1, 0<b<1, 0≤c≤0.5이고, a+b+c=1을 만족한다.

[0016] [2] The present invention provides a metal salt for a positive electrode active material precursor, wherein the compound represented by the chemical formula 1 in [1] has the composition of the chemical formula 1-1 below, and the metal salt for a positive electrode active material precursor is in the form of a solid solution in which nickel, cobalt, and manganese are homogeneously distributed to form a single phase.

[0017] [Chemical Formula 1-1]

[0018] (Ni a1 Mn b1 Co c1 M 2 d1 )X 1

[0019] In the above chemical formula 1-1,

[0020] M 2 is one or more selected from the group consisting of Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0021] X 1 It is SO4 or (NO3)2, and

[0022] a1, b1, c1, and d1 are 0.50≤a1<1, 0 respectively. <b1≤0.4, 0<c1≤0.4, 0≤d1≤0.1이고, a1+b1+c1+d1=1을 만족한다.

[0023] [3] The present invention provides a metal salt for a positive electrode active material precursor, wherein, in [1] or [2], the compound represented by Formula 1 has the composition of Formula 1-2 below.

[0024] [Chemical Formula 1-2]

[0025] (Ni a2 Mn b2 M 1 c2 )X 2

[0026] In the above chemical formula 1-2,

[0027] M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0028] X 2 is SO4 or (NO3)2, and

[0029] a2, b2, and c2 are each 0 <a2≤0.5, 0.5≤b2<1, 0≤c2<0.5이고, a2+b2+c2=1을 만족한다.

[0030] [4] The present invention provides a method for preparing a metal salt for a positive electrode active material precursor, comprising the steps of: dissolving a nickel raw material and a manganese raw material in water to prepare an aqueous solution of a transition metal; and rapidly cooling the aqueous solution of the transition metal to precipitate a solid precipitate, wherein the nickel raw material and the manganese raw material are each sulfates or nitrates of these metals.

[0031] [5] The present invention provides a method for preparing a metal salt for a positive electrode active material precursor, wherein, in [4] the step of preparing the transition metal aqueous solution is performed at a temperature of 20°C or higher and below the boiling point, or under supercritical conditions.

[0032] [6] The present invention provides a method for manufacturing a metal salt for a positive electrode active material precursor, wherein, in [4] or [5], the rapid cooling lowers the transition metal aqueous solution by more than 10°C within 1 second.

[0033] [7] The present invention provides a positive active material precursor comprising a calcined body of a metal salt for a positive active material precursor according to at least one of [1] to [3].

[0034] [8] The present invention provides a positive active material precursor according to [7], wherein the positive active material precursor comprises a compound represented by the following chemical formula 2.

[0035] [Chemical Formula 2]

[0036] (Ni a Mn b M 1 c )O2

[0037] In the above chemical formula 2,

[0038] M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0039] a, b, and c are each 0 <a<1, 0<b<1, 0≤c≤0.5이고, a+b+c=1을 만족한다.

[0040] [9] The present invention provides a positive active material precursor, wherein, in [7] or [8], the precursor is in the form of a non-spherical secondary particle.

[0041]

[0010] The present invention provides a positive electrode active material comprising a lithium composite transition metal oxide, which is a calcined body of a mixture of a positive electrode active material precursor according to at least one of [7] to [9] and a lithium lithium raw material.

[0042]

[0011] The present invention provides a positive electrode active material, wherein, in

[0010] the lithium composite transition metal oxide has a composition of the following formula 3 or formula 4.

[0043] [Chemical Formula 3]

[0044] Li 1+x (Ni a3 Mn b3 M 1 c3 )O2

[0045] In the above chemical formula 3,

[0046] M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0047] x, a3, b3, and c3 are -0.20≤x≤0.20, 0, respectively. <a3≤0.5, 0.5≤b3<1, 0≤c3<0.5이며, a3+b3+c3=1을 만족하며,

[0048] [Chemical Formula 4]

[0049] xLi2Mn (1-p) M 1 p O3·(1-x)LiNi q Mn r M 1 s O2

[0050] In the above chemical formula 4,

[0051] M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0052] x, p, q, r, and s are each 0 <x<1.0, 0≤p≤0.5, 0<q<1.0, 0<r<1.0, 0≤s≤0.5이며, q+r+s=1을 만족한다.

[0053]

[0012] The present invention provides a positive electrode active material, wherein, in

[0010] or

[0011] , the positive electrode active material is a single-particle positive electrode active material comprising 50 or fewer nodules.

[0054]

[0013] The present invention provides a positive electrode comprising at least one positive electrode active material among

[0010] to

[0012] .

[0055]

[0014] The present invention provides a lithium secondary battery comprising: a positive electrode according to

[0013] ; a negative electrode comprising a negative electrode active material; a separator interposed between the positive electrode and the negative electrode; and an electrolyte.

[0056] When manufacturing a positive electrode active material precursor using a metal salt for a positive electrode active material precursor according to the present invention, there is an advantage of saving manufacturing costs and time compared to the conventional co-precipitation method.

[0057] In addition, the positive active material manufactured using the above precursor has the effect of improving the initial capacity of a lithium secondary battery under high voltage conditions of 4.5V or higher.

[0058] Figure 1 is a photograph of the positive electrode active material precursor particles prepared in the example, observed through a scanning electron microscope (SEM).

[0059] Figure 2 is a scanning electron microscope (SEM) image of the positive active material precursor particles prepared in the comparative example.

[0060] Figure 3 is a photograph of the positive active material particles prepared in the example, observed through a scanning electron microscope (SEM).

[0061] Figure 4 is a scanning electron microscope (SEM) image of the positive active material particles prepared in the comparative example.

[0062] Hereinafter, the present invention will be described in more detail to aid in understanding the invention.

[0063]

[0064] In the present invention, “solid solution” refers to a form in which nickel, cobalt, and manganese are homogeneously distributed to form a single phase, and the solid solution form can be confirmed through X-ray diffraction analysis (XRD analysis). The X-ray diffraction analysis can be performed by using a Bruker D8 Endeavor (light source: Cu-Kα, λ=1.54Å) equipped with a LynxEye XE-T-position sensitive detector, placing a sample into a groove of a general powder holder, smoothing the sample surface using a slide glass, filling the sample so that its height matches the edge of the holder, and then setting the conditions to FDS 0.5°, 2θ=15° ~ 90° range with a step size of 0.02° and a total scan time of approximately 20 minutes.

[0065] In the present invention, "single particle type" refers to a particle composed of 50 or fewer nodules, and is a concept that includes a single particle composed of one nodule and a pseudo-single particle which is a complex of 2 to 50 nodules.

[0066] The above "nodule" is a sub-grain unit constituting a single particle and a pseudo-single particle, and may be a single crystal that does not have crystalline grain boundaries, or a polycrystalline material that does not appear to have grain boundaries when observed at a field of view of 5,000 to 20,000 times using a scanning electron microscope.

[0067] In the present invention, "particle" is a concept that includes any one or all of a single particle, a pseudo-single particle, a primary particle, a nodule, and a secondary particle.

[0068] In the present invention, "secondary particle" refers to a particle formed by the aggregation of a plurality of primary particles, for example, tens to hundreds of primary particles. Specifically, the secondary particle may be an aggregate of more than 50 primary particles.

[0069] In the present invention, “D 50"This refers to the particle size corresponding to 50% of the volume cumulative amount in the volume cumulative particle size distribution of the corresponding particle powder, and can be measured using the laser diffraction method. For example, after dispersing the precursor powder or the cathode active material powder in a dispersion medium, it can be introduced into a commercially available laser diffraction particle size measuring device (e.g., Malvern, Mastersizer 3000), irradiated with ultrasound of about 28 kHz at an output of 60 W, and then obtained a volume cumulative particle size distribution graph, and the particle size at the point where the volume cumulative amount is 50% in the obtained volume cumulative particle size distribution graph can be measured.

[0070]

[0071] Co-precipitation, utilizing the precipitation reaction of metal ions in aqueous solutions, is primarily used in the precursor synthesis process for manufacturing lithium complex transition metal oxides, such as lithium nickel cobalt manganese oxides and over-lithium manganese oxides. However, co-precipitation has the disadvantage of being time-consuming and costly, as it involves multiple chemical reaction steps as well as processes such as washing and filtration. In particular, production efficiency may decrease because conditions such as temperature, pH, and concentration must be finely controlled to regulate the reaction rate. Furthermore, since precipitating agents are used in the co-precipitation process, a large amount of wastewater is generated. As this wastewater contains metal ions and reaction byproducts, the burden of wastewater treatment is significant. Wastewater treatment costs can also contribute to an increase in overall manufacturing costs.

[0072] Accordingly, the inventors conducted extensive research to develop a method for manufacturing precursors for cathode active materials that is faster, simpler, and has lower manufacturing costs compared to the co-precipitation method. As a result, they confirmed that metal complex metal salts can be obtained through a relatively simple process by utilizing the temperature-dependent solubility differences of metal raw materials, and that oxide-type precursors can be manufactured by heat-treating these salts, thereby completing the present invention.

[0073] Specifically, when metal raw materials such as metal sulfates and metal nitrates are dissolved in water at high temperatures and then rapidly cooled, nickel-manganese complex metal salts in the form of solid solutions are precipitated due to differences in solubility depending on temperature, and precursors can be easily manufactured using this.

[0074]

[0075] Below, each component constituting the present invention will be described in more detail.

[0076]

[0077] Metal salt for positive electrode active material precursor

[0078] A metal salt for a positive electrode active material precursor according to one embodiment of the present invention comprises a compound represented by the following chemical formula 1, and is in the form of a non-spherical secondary particle solid solution in which nickel and manganese are homogeneously distributed to form a single phase.

[0079] [Chemical Formula 1]

[0080] (Ni a Mn b M 1 c )X

[0081] In the above chemical formula 1,

[0082] M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0083] X is SO4 or (NO3)2, and

[0084] a, b, and c are each 0 <a<1, 0<b<1, 0≤c≤0.5이고, a+b+c=1을 만족한다.

[0085] In one embodiment, the compound represented by Chemical Formula 1 has the composition of Chemical Formula 1-1 below, and the metal salt for the positive electrode active material precursor may be in the form of a solid solution in which nickel, cobalt, and manganese are homogeneously distributed to form a single phase.

[0086] [Chemical Formula 1-1]

[0087] (Ni a1 Mn b1 Co c1 M 2 d1 )X 1

[0088] In the above chemical formula 1-1,

[0089] M 2 is one or more selected from the group consisting of Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0090] X 1 It is SO4 or (NO3)2, and

[0091] a1, b1, c1, and d1 are 0.50≤a1<1, 0 respectively. <b1≤0.4, 0<c1≤0.4, 0≤d1≤0.1이고, a1+b1+c1+d1=1을 만족한다.

[0092] The above a1 represents the molar ratio of nickel among the metals in the metal salt, and can satisfy 0.6≤a1<1, 0.7≤a1<1, or 0.8≤a1<1. It is desirable that the nickel content is within the above range, as it exhibits high energy density and enables the realization of high capacity.

[0093] The above b1 represents the molar ratio of manganese among the metals in the metal salt, 0 <b1≤0.3, 0<b1≤0.25, 또는 0<b1≤0.15을 만족할 수 있다.

[0094] The above c1 represents the molar ratio of cobalt among the metals in the metal salt, 0 <c1≤0.3, 0<c1≤0.25, 또는 0<c1≤0.15을 만족할 수 있다.

[0095] The above d1 is M among the metals in the metal salt. 2 It represents the molar ratio of the elements and can satisfy 0≤d1≤0.08, 0≤d1≤0.05, or 0≤d1≤0.03.

[0096] In another embodiment, the compound represented by the above chemical formula 1 may have the composition of the following chemical formula 1-2.

[0097] [Chemical Formula 1-2]

[0098] (Ni a2 Mn b2 M 1 c2 )X 2

[0099] In the above chemical formula 1-2,

[0100] M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0101] X 2 is SO4 or (NO3)2, and

[0102] a2, b2, and c2 are each 0 <a2≤0.5, 0.5≤b2<1, 0≤c2<0.5이고, a2+b2+c2=1을 만족한다.

[0103] The above a2 represents the molar ratio of nickel among the metals in the metal salt, and may satisfy 0.1≤a2≤0.5, 0.2≤a2≤0.5, or 0.3≤a2≤0.4.

[0104] The above b2 represents the molar ratio of manganese among the metals in the metal salt, and may satisfy 0.5≤b2≤0.9, 0.5≤b2≤0.8, or 0.6≤b2≤0.7.

[0105] The above c2 is M among the metals in the metal salt. 1 Representing the molar ratio of elements, 0 ≤ c² ≤ 0.35, 0 ≤ c² ≤ 0.30, or 0 <c2≤0.25을 만족할 수 있다.

[0106] Specifically, the metal salt for the positive electrode active material precursor may have the composition of Formula 1, and more specifically, may have the composition of Formula 1-1 or Formula 1-2.

[0107]

[0108] The above method for manufacturing a metal salt for a positive electrode active material precursor comprises the steps of: dissolving a nickel raw material and a manganese raw material in water to prepare an aqueous transition metal solution; and rapidly cooling the aqueous transition metal solution to precipitate a solid precipitate, wherein the nickel raw material and the manganese raw material are each a sulfate or nitrate of these metals.

[0109] By the above rapid cooling, a metal salt for a positive electrode active material precursor in the form of a solid solution in which the aforementioned nickel and manganese are homogeneously distributed to form a single phase can be obtained.

[0110] Conventional spray pyrolysis is a method in which a solution containing dissolved transition metals is sprayed into droplets ranging in size from a few micrometers to tens of micrometers, and then exposed to a high-temperature atmosphere of 200°C or higher to evaporate the solvent and leave only the solute in a solid state. Since this is a process in which droplets are converted from a high-temperature gas into a solid, it differs from the present invention, which utilizes a precipitation phenomenon in which the solid is supersaturated within the solution.

[0111] In the spray pyrolysis method, the temperature difference during the process of converting high-temperature gas into a solid is much greater than that of the rapid cooling process of the present invention, so it may be difficult to obtain a single phase with a homogeneous distribution of transition metals as in the present invention, and it is also disadvantageous compared to the present invention in terms of the cost of maintaining high-temperature conditions and production speed.

[0112] In addition, since the spray pyrolysis method is a method in which one droplet becomes one solid particle, a spherical single particle shape is usually obtained, but in the present invention, a non-spherical secondary particle shape can be obtained. When using a metal salt having such a non-spherical secondary particle shape, there is an advantage that it is easy to control the size and shape of the final cathode active material by controlling the temperature and the amount of lithium input during the subsequent calcination process.

[0113] D of the metal salt for the above positive active material precursor 50 The thickness may be 0.1㎛ to 5㎛, preferably 0.5㎛ to 3㎛, and more preferably 1㎛ to 2㎛.

[0114] At this time, the input amount of each metal raw material can be determined by considering the molar ratio of the metal in the cathode active material to be finally produced.

[0115] When the metal salt for the anode active material precursor comprises nickel, cobalt, and manganese, as a specific example, when having the composition of Chemical Formula 1-1, the transition metal aqueous solution may further include a cobalt raw material.

[0116] The solubility of nickel and manganese raw materials in water varies with temperature. Therefore, if the aforementioned raw materials are dissolved in water at a temperature of high solubility to prepare an aqueous transition metal solution, and then rapidly cooled to a temperature of low solubility, a nickel-manganese complex metal salt compound in the form of a solid solution precipitates. Similarly, even if the aqueous transition metal solution further contains cobalt raw material, if the solution is prepared by dissolving it in water at a temperature of high solubility and then rapidly cooled to a temperature of low solubility, a nickel-cobalt-manganese complex metal salt compound in the form of a solid solution precipitates.

[0117] The above nickel raw material, cobalt raw material, and manganese raw material may each be a sulfate or nitrate of these metals.

[0118] The above nickel raw material may be nickel sulfate, which is NiSO4, NiSO4·6H2O, or a mixture thereof; or nickel nitrate, which is Ni(NO3)2·6H2O.

[0119] The above manganese raw material may be manganese sulfate, which is MnSO4, MnSO4·H2O, or a mixture thereof; or manganese nitrate, which is Mn(NO3)2.

[0120] The above cobalt raw material may be cobalt sulfate, which is CoSO4, CoSO4·7H2O, or a mixture thereof; or cobalt nitrate, which is Co(NO3)2·6H2O.

[0121] The step of preparing the above transition metal aqueous solution may be carried out at a temperature of 20°C or higher and below the boiling point, or under supercritical conditions. The temperature at which the step of preparing the above transition metal aqueous solution is performed may vary depending on atmospheric pressure conditions. When the preparation of the above transition metal aqueous solution is carried out under 1 atm to 218 atm, the boiling point may be 100°C to 374°C.

[0122] The step of preparing the above transition metal aqueous solution can be performed at a temperature of 20°C or higher and less than 100°C under atmospheric pressure, specifically at 30°C to 80°C, and more specifically at 35°C to 50°C.

[0123] For complete melting of metal raw materials, it must be carried out at a temperature of 20°C or higher, but if the temperature is excessively high, it may vaporize beyond the boiling point of water, so it is desirable to be within the above range.

[0124] The rapid cooling described above may involve lowering the temperature of the transition metal aqueous solution by 10°C or more, preferably 15°C or more, and more preferably 20°C or more within 1 second. The rapid cooling must be performed at a temperature at least 10°C lower than the temperature of the transition metal aqueous solution for the precipitation of metal raw materials, but since an excessively low temperature would result in a temperature lower than the freezing point of water, it may involve lowering the temperature to 0°C or more, preferably 5°C or more, and more preferably 10°C or more.

[0125] If necessary, the above transition metal aqueous solution contains doping elements (M) in addition to nickel, cobalt, and manganese. 1 It may further include ). In this case, the above M 1 It may be one or more selected from the group consisting of Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg and B.

[0126] The above transition metal aqueous solution is the above doping element M 1 If further included, the doping element M during the preparation of the transition metal aqueous solution 1 Sulfates or nitrates containing may be optionally added.

[0127]

[0128] positive electrode active material precursor

[0129] The positive active material precursor according to the present invention comprises a calcined body of the metal salt for the positive active material precursor.

[0130] That is, a positive electrode active material precursor can be manufactured by heat-treating a metal salt for the positive electrode active material precursor.

[0131] A method for manufacturing a positive electrode active material precursor according to one embodiment of the present invention includes the step of heat-treating the metal salt for the positive electrode active material precursor. By heat treatment, the metal salt changes into an oxide form.

[0132] The above heat treatment can be performed at 600°C to 900°C, preferably 700°C to 900°C, and more preferably 750°C to 850°C. Considering that the decomposition temperature of the nickel raw material is 600°C or higher, it is preferable that the heat treatment be performed at a temperature of 600°C or higher. However, to prevent cost increases caused by unnecessarily excessive heat treatment, it is preferable that the temperature be 900°C or lower.

[0133] The above heat treatment may be performed for 5 to 20 hours, preferably 5 to 15 hours, and more preferably 5 to 10 hours. Considering that all S or N-containing compounds must be converted into oxides, it is preferable to perform the heat treatment for 5 hours or more. However, since the process cost may increase if the process becomes too long, it is preferable to perform it for 20 hours or less.

[0134] The above positive active material precursor may include a compound represented by the following chemical formula 2.

[0135] [Chemical Formula 2]

[0136] (Ni a Mn b M 1 c )O2

[0137] In the above chemical formula 2,

[0138] M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0139] a, b, and c are each 0 <a<1, 0<b<1, 0≤c≤0.5이고, a+b+c=1을 만족한다.

[0140] When the compound represented by the above chemical formula 1 has the composition of the above chemical formula 1-1, the positive active material precursor prepared by heat-treating the metal salt for the positive active material precursor may include a compound represented by the following chemical formula 2-1.

[0141] [Chemical Formula 2-1]

[0142] (Ni a1 Mn b1 Co c1 M 2 d1 )O2

[0143] In the above chemical formula 2-1,

[0144] M 2 is one or more selected from the group consisting of Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0145] a1, b1, c1, and d1 are 0.50≤a1<1, 0 respectively. <b1≤0.4, 0<c1≤0.4, 0≤d1≤0.1이며, a1+b1+c1+d1=1을 만족한다.

[0146] In addition, if the compound represented by Chemical Formula 1 has the composition of Chemical Formula 1-2, the positive active material precursor prepared by heat-treating the metal salt for the positive active material precursor may include a compound represented by Chemical Formula 2-2 below.

[0147] [Chemical Formula 2-2]

[0148] (Ni a2 Mn b2 M 1 c2 )O2

[0149] In the above chemical formula 2-2,

[0150] M 1is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0151] a2, b2, and c2 are each 0 <a2≤0.5, 0.5≤b2<1, 0≤c2<0.5이며, a2+b2+c2=1을 만족한다.

[0152] Specifically, the positive active material precursor may have a composition represented by the chemical formula 2, and more specifically, may have the composition of the chemical formula 2-1 or 2-1.

[0153] The descriptions of a, a1, a2, b, b1, b2, c, c1, c2, d, and d1 in the above chemical formulas 2, 2-1, and 2-2 are the same as the descriptions in the above chemical formulas 1, 1-1, and 1-2.

[0154] D of the above positive active material precursor 50 The depth may be 0.1㎛ to 5.0㎛, preferably 0.3㎛ to 3.0㎛, and more preferably 0.5㎛ to 2.0㎛.

[0155] The above-mentioned positive active material precursor may be in the form of secondary particles in which a plurality of primary particles are aggregated.

[0156] A positive electrode active material precursor according to one embodiment of the present invention is manufactured by the method for manufacturing the positive electrode active material precursor, and since the manufacturing method does not use a co-precipitation method using a complexing agent and a basic compound, it has the advantage of saving manufacturing time and cost and facilitating wastewater treatment.

[0157]

[0158] positive electrode active material

[0159] A positive electrode active material according to one embodiment of the present invention comprises a lithium composite transition metal oxide, which is a calcined body of a mixture of the positive electrode active material precursor and a lithium raw material.

[0160] The above lithium complex transition metal oxide may have the composition of Chemical Formula 3 below.

[0161] [Chemical Formula 3]

[0162] Li 1+x (Ni a3 Mn b3 M 1 c3 )O2

[0163] In the above chemical formula 3,

[0164] M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0165] x, a3, b3, and c3 are -0.20≤x≤0.20, 0, respectively. <a3≤0.5, 0.5≤b3<1, 0≤c3<0.5이며, a3+b3+c3=1을 만족한다.

[0166] In one embodiment of the present invention, the lithium composite transition metal oxide may have the composition of the following chemical formula 3-1.

[0167] [Chemical Formula 3-1]

[0168] Li 1+x (Ni a3 Mn c3 Co b3 M 2 d3 )O2

[0169] In the above chemical formula 3,

[0170] M 2 is one or more selected from the group consisting of Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0171] x, a3, b3, c3, and d3 are -0.20≤x≤0.20, 0.5≤a3<1, 0, respectively. <b3≤0.4, 0<c3≤0.4, 0≤d3≤0.1, a3+b3+c3+d3=1을 만족한다.

[0172] The above 1+x represents the molar ratio of lithium in the lithium composite transition metal oxide, and may be 0≤x≤0.20 or 0≤x≤0.10. When the molar ratio of lithium satisfies the above range, the crystal structure can be stably formed.

[0173] The above a3 represents the molar ratio of nickel among the metals excluding lithium in the lithium composite transition metal oxide, and can satisfy 0.6≤a3<1, 0.7≤a3<1, or 0.8≤a3<1. It is desirable that the nickel content is within the above range, as it exhibits high energy density and enables the realization of high capacity.

[0174] The above b3 represents the molar ratio of manganese among the metals excluding lithium in the lithium composite transition metal oxide, where 0 <b3≤0.35, 0<b3≤0.30, 또는 0<b3≤0.25을 만족할 수 있다.

[0175] The above c3 represents the molar ratio of cobalt among the metals excluding lithium in the lithium composite transition metal oxide, and 0 <c3≤0.35, 0<c3≤0.30, 또는 0<c3≤0.25을 만족할 수 있다.

[0176] The above d3 is M among the metals excluding lithium in the above lithium complex transition metal oxide. 2 It represents the molar ratio of the elements and can satisfy 0≤d3≤0.08, 0≤d3≤0.05, or 0≤d3≤0.03.

[0177] In another embodiment, the lithium composite transition metal oxide may have the composition of the following chemical formula 4.

[0178] [Chemical Formula 4]

[0179] xLi2Mn (1-p) M1 p O3·(1-x)LiNi q Mn r M 1 s O2

[0180] In the above chemical formula 4,

[0181] M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and

[0182] x, p, q, r, and s are each 0 <x<1.0, 0≤p≤0.5, 0<q<1.0, 0<r<1.0, 0≤s≤0.5이며, q+r+s=1을 만족한다.

[0183] The above positive active material may be a single-particle type positive active material containing 50 or fewer nodules.

[0184] D of the above positive active material 50 The depth may be 0.1㎛ to 5.0㎛, preferably 0.3㎛ to 3.0㎛, and more preferably 0.5㎛ to 2.0㎛.

[0185] By using the metal salt for the positive active material precursor according to the present invention, a single-particle type positive active material with such small particle size can be formed without a separate grinding process. D 50 The single-particle cathode active material within the above range has a large specific surface area, which is advantageous for improving the capacity of the battery.

[0186] In one embodiment of the present invention, the method for manufacturing the positive electrode active material comprises the step of mixing the aforementioned positive electrode active material precursor and a lithium raw material and calcining them to form a lithium composite transition metal oxide, and, except for using the positive electrode active material precursor as the precursor, a conventional method for manufacturing a positive electrode active material in the industry may be applied.

[0187] As the above lithium raw material, lithium-containing sulfates, nitrates, acetates, carbonates, oxalates, citrates, halides, hydroxides, or oxyhydroxides may be used, for example, Li2CO3, LiNO3, LiNO2, LiOH, LiOH·H2O, LiH, LiF, LiCl, LiBr, LiI, CH3COOLi, Li2O, Li2SO4, CH3COOLi, Li3C6H5O7, or mixtures thereof may be used.

[0188] The above lithium raw material and precursor can be mixed such that the molar ratio of Li : (total metal in the precursor) is 1:1 to 1.8:1, preferably 1:1 to 1.6:1. When the mixing ratio of the lithium raw material and the metal in the precursor satisfies the above range, a positive electrode active material with excellent capacity characteristics and structural stability can be manufactured by developing a layered crystal structure of the lithium composite transition metal oxide.

[0189] Next, a step of calcining the mixture of the positive electrode active material precursor and the lithium raw material is performed. Specifically, the calcination can be performed by calcining at 600°C to 1,000°C, preferably 650°C to 850°C, more preferably 700°C to 800°C for 15 to 24 hours under an oxygen atmosphere.

[0190]

[0191] anode

[0192] Next, the anode according to the present invention will be described.

[0193] The anode according to the present invention comprises the aforementioned anode active material. Specifically, the anode comprises an anode current collector; and an anode active material layer formed on the anode current collector and comprising the anode active material. Since the anode active material has been described above, a description thereof is omitted, and components excluding the anode active material are described below.

[0194] In the above-mentioned positive electrode, the positive current collector is not particularly limited as long as it is conductive without causing chemical changes 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 above-mentioned positive current collector may typically have a thickness of 3 to 500 μm, and fine irregularities may be formed on the surface of the above-mentioned positive current collector to increase the adhesion of the positive active material. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0195] In addition, the above-described positive active material layer may include a conductive material and a binder along with the positive active material described above.

[0196] The above positive active material may typically be included in an amount of 80% to 99% by weight, preferably 90% to 98% by weight, and more preferably 95% to 97% by weight, based on the total weight of the positive active material layer.

[0197] The above conductive material is used to impart conductivity to the electrode, and in the battery being constructed, it may be used without special limitations as long as it possesses electronic conductivity without causing chemical changes. Specific examples include graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, or thermal black; carbon-based materials such as carbon fibers or carbon nanotubes; metal powders or metal fibers such as copper, nickel, aluminum, or 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 one of these alone or a mixture of two or more may be used. The above conductive material may typically be included in an amount of 0.5% to 20% by weight, preferably 1% to 10% by weight, and more preferably 1% to 5% by weight, based on the total weight of the positive electrode active material layer.

[0198] The above binder serves to improve adhesion between positive active material particles and adhesion between the positive active material and the positive current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer rubber (EPDM rubber), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one of these alone or a mixture of two or more may be used. The above binder may be included in an amount of 0.5% to 20% by weight, preferably 1% to 10% by weight, and more preferably 1% to 5% by weight, based on the total weight of the positive active material layer.

[0199] The above anode can be manufactured according to a conventional anode manufacturing method. For example, the above anode can be manufactured by mixing an anode active material, a binder, and / or a conductive material in a solvent to prepare an anode slurry, applying the anode slurry onto an anode current collector, and then drying and rolling.

[0200] The above solvent may be a solvent commonly used in the relevant technical field, and may include dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water, and one of these alone or a mixture of two or more may be used. The amount of the above solvent used is sufficient if it has a viscosity that dissolves or disperses the anode active material, conductive material, and binder, taking into account the coating thickness of the slurry and the manufacturing yield, and subsequently provides excellent thickness uniformity when coated for anode manufacturing.

[0201] Alternatively, the anode may be manufactured by casting the anode slurry onto a separate support and then laminating the film obtained by peeling off from the support onto an anode current collector.

[0202]

[0203] lithium secondary battery

[0204] Next, a lithium secondary battery according to the present invention will be described.

[0205] Specifically, the above lithium secondary battery comprises a positive electrode, a negative electrode including a negative electrode active material, and a separator and an electrolyte interposed between the positive electrode and the negative electrode. Since the positive electrode is the same as previously described, a detailed description is omitted, and only the remaining components are described in detail below.

[0206] Additionally, the lithium secondary battery may optionally further include a battery container that accommodates the electrode assembly of the positive electrode, negative electrode, and separator, and a sealing member that seals the battery container.

[0207] In the above lithium secondary battery, the negative electrode comprises a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector.

[0208] The above-mentioned negative 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., and aluminum-cadmium alloy may be used. In addition, the above-mentioned negative current collector may typically have a thickness of 3 μm to 500 μm, and, similar to the positive current collector, fine irregularities may be formed on the surface of the current collector to strengthen the bonding strength of the negative active material. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0209] The above-mentioned cathode active material layer optionally includes a binder and a conductive material together with the cathode active material.

[0210] As the above-mentioned negative electrode active material, a compound capable of reversible intercalation and deintercalation of lithium may be used. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic materials capable of alloying with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloys, Sn alloys, or Al alloys; and SiO₂ βExamples include metal oxides capable of doping and dedoping lithium, such as (0 < β < 2), SnO2, vanadium oxide, and lithium vanadium oxide; or composites comprising the metal material and carbonaceous material, such as Si-C composites or Sn-C composites, and any one or more of these may be used.

[0211] In one embodiment of the present invention, the negative electrode active material may be graphite, the Si-containing material, or a mixture thereof, specifically graphite, more specifically a mixture of artificial graphite and natural graphite. Additionally, a metallic lithium thin film may be used as the negative electrode active material. The negative electrode active material may be included in an amount of 80% to 99% by weight based on the total weight of the negative electrode active material layer.

[0212] The above binder is a component that assists in the bonding between the conductive material, the active material, and the current collector, and is typically added in an amount of 0.1% to 10% by weight based on the total weight of the negative electrode active material layer. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof.

[0213] The above conductive material is a component for further improving the conductivity of the negative electrode active material, and may be added in an amount of 10% by weight or less, preferably 5% by weight or less, based on the total weight of the negative electrode active material layer. Such conductive material is not particularly limited as long as it is conductive without causing chemical changes in the battery, and for example, graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black; conductive fibers such as carbon fibers or metal fibers; fluorinated carbon; metal powder such as aluminum or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives may be used.

[0214] The above-mentioned cathode active material layer may be manufactured by applying a cathode composite material, prepared by dissolving or dispersing a cathode active material and optionally a binder and a conductive material in a solvent, onto a cathode current collector and drying it, or by casting the cathode composite material onto a separate support and then laminating the film obtained by peeling it off from the support onto a cathode current collector.

[0215] Meanwhile, in the above-mentioned lithium secondary battery, the separator separates the negative electrode and the positive electrode and provides a pathway for the movement of lithium ions. Any separator typically used in lithium secondary batteries can be used without special limitations, and it is particularly desirable that it has low resistance to the movement of electrolyte ions and excellent electrolyte moisture retention capacity. Specifically, a porous polymer film, such as a porous polymer film made of a polyolefin-based polymer like ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof may be used. In addition, a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fiber or polyethylene terephthalate fiber, may be used. Furthermore, a coated separator containing ceramic components or polymer materials may be used to ensure heat resistance or mechanical strength, and it may optionally be used in a single-layer or multi-layer structure.

[0216] In addition, the electrolytes used in the present invention may include organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, molten inorganic electrolytes, etc., which are usable when manufacturing lithium secondary batteries, but are not limited to these.

[0217] Specifically, the electrolyte may include an organic solvent and a lithium salt.

[0218] 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 solvent may 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), ethylmethyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC). 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 2 to 20 carbon atoms and may include a double bond-directing ring or ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes may be used. Among these, carbonate-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.

[0219] The above lithium salt may be used without special restrictions as long as it is a compound capable of providing lithium ions used in lithium secondary batteries. Specifically, the anion of the above lithium salt is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - It may be at least one selected from the group consisting of LiPF6, LiN(SO2F)2(LiFSI), LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO2, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, and LiB(C2O4)2, and more specifically, it may be LiPF6. The concentration of the lithium salt may be 0.1M to 4.0M, preferably 0.5M to 3.0M, and more preferably 1.0M to 2.0M. When the concentration of the lithium salt falls within the above range, the electrolyte has appropriate conductivity and viscosity, so it can exhibit excellent electrolyte performance and lithium ions can move effectively.

[0220] 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. In this case, the above additives may be included in an amount of 0.1 to 5 weight% based on the total weight of the electrolyte.

[0221] The lithium secondary battery of the present invention may have a charge cut-off voltage (full charge voltage) of 4.5V or higher, 4.55V or higher, 4.6V or higher, or 4.65V or higher. In addition, when operated under the charge cut-off voltage conditions, the initial efficiency may be 90% or higher.

[0222] The external shape of the lithium secondary battery of the present invention is not particularly limited, but can be a cylindrical shape using a can, a prismatic shape, a pouch shape, or a coin shape.

[0223] As described above, since the lithium secondary battery containing the positive electrode active material according to the present invention exhibits stable high-temperature performance, it can be used not only as a battery cell used as a power source for small devices such as mobile phones, laptop computers, and digital cameras, but can also be preferably used as a unit cell for a battery module for medium to large devices containing a plurality of battery cells.

[0224] Examples of the above-mentioned medium-to-large devices include, but are not limited to, power tools, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and power storage systems.

[0225] According to another embodiment of the present invention, a battery module comprising the lithium secondary battery as a unit cell and a battery pack comprising the same are provided.

[0226]

[0227] The present invention will be explained in more detail below through specific embodiments.

[0228] [Example: Preparation of positive electrode active material]

[0229] Example.

[0230] (1) Preparation of a positive electrode active material precursor

[0231] NiSO4, MnSO4, and CoSO4 were mixed to have a molar ratio of Ni:Mn:Co=15:75:10, and this mixture was dissolved in deionized water at 40°C under atmospheric pressure to prepare an aqueous solution with a concentration of 35 wt%.

[0232]

[0233] The prepared aqueous solution was rapidly cooled to 20°C in 1 second to form a solid precipitate. Subsequently, by separating the solid precipitate using a filtration filter (Ni 0.15 Mn 0.75 Co 0.1 A metal salt having an SO4 composition was prepared.

[0234] The separated solid precipitate was dried under vacuum and at 110°C, and then heat-treated under air and at 800°C for 10 hours (Ni 0.15 Mn 0.75 Co 0.1 A positive electrode active material precursor having an O2 composition was prepared.

[0235]

[0236] (2) Preparation of positive electrode active material

[0237] The above precursor was mixed with an amount of Li2CO3 such that the molar ratio of Li:(Ni+Co+Mn) is 1.55:1, and then heat-treated in an atmospheric reactor at 650°C for 5 hours to produce 0.5Li2MnO3·0.5LiNi0.3 Mn 0.5 Co 0.2 A positive electrode active material having the composition of O2 was prepared.

[0238]

[0239] Comparative example.

[0240] (1) Preparation of a positive electrode active material precursor

[0241] 4 L of distilled water was added to a co-precipitation reactor (capacity 20 L), and 100 mL of an aqueous ammonia solution with a concentration of 28 wt% was added while maintaining the temperature at 50°C under a nitrogen atmosphere.

[0242] Then, a transition metal solution with a concentration of 3.2 mol / L, mixed with NiSO4, CoSO4, and MnSO4 at a molar ratio of Ni:Co:Mn of 15:10:75, was continuously fed into the above co-precipitation reactor at a rate of 30 mL / Hr, and a 28 wt% aqueous ammonia solution was fed into the reactor at a rate of 42 mL / hr. The impeller speed was stirred at 400 rpm, and a 40 wt% sodium hydroxide solution was fed to maintain the pH of the reaction solution at 11.0 while co-precipitating the reaction for 24 hours to form precursor particles.

[0243] The above precursor particles were separated, washed, and dried in an oven at 130°C to prepare the precursor.

[0244]

[0245] (2) Preparation of positive electrode active material

[0246] The above precursor is mixed with an amount of Li2CO3 such that the molar ratio of Li:(Ni+Co+Mn) is 1.55:1, and then heat-treated in a reactor under an atmospheric atmosphere at a temperature of 650°C for 5 hours to Li 1.5 [Ni 0.15 Co 0.10 Mn 0.75 ]O 2.5 A positive electrode active material having the composition was prepared.

[0247]

[0248] [Experimental Example]

[0249] Experimental Example 1. SEM imaging

[0250] The results of observing each positive electrode active material precursor prepared in the above examples and comparative examples using a scanning electron microscope are shown in FIGS. 1 and FIGS. 2, respectively. In addition, the results of observing each positive electrode active material prepared in the above examples and comparative examples are shown in FIGS. 3 and FIGS. 4, respectively.

[0251]

[0252] Experimental Example 2. Initial Dose Evaluation

[0253] (1) Manufacturing of batteries

[0254] A positive electrode slurry was prepared by mixing the positive electrode active material prepared in the above examples and comparative examples, carbon black as a conductive material, and PVDF as a binder in a weight ratio of 90:5:5 in N-methylpyrrolidone (NMP). The prepared positive electrode slurry was applied to one side of an aluminum current collector and dried at 100°C, then placed between two rolling rolls and rolled to produce a positive electrode.

[0255] An electrode assembly was manufactured by interposing a porous polyethylene-based separator between the manufactured anode and a lithium metal cathode, then inserting it into a case and injecting an electrolyte to manufacture a half-cell. At this time, as the electrolyte, a solution of 1.0 M LiPF6 dissolved in an organic solvent mixed with ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 3:4:3 was used.

[0256]

[0257] (2) Capacity evaluation

[0258] Each of the above-mentioned half-cells was charged to 4.65V at 0.1C in CC-CV mode at 45℃ (cutoff current 0.05C) and discharged to 2.5V at a constant current of 0.1C. The discharge capacity measured during this process is listed in Table 1 below.

[0259] Example Comparison Brush Cutter Discharge Capacity [mAh / g] 300.3295.1

[0260] Through the results of Table 1 above, it can be confirmed that the positive electrode active material prepared using the precursor of the example is more advantageous for improving the initial capacity under high-voltage operating conditions of a lithium secondary battery compared to the positive electrode active material prepared using the precursor of the comparative example, even though the example underwent a simple precursor synthesis process that did not require multiple steps of chemical reactions using complexing agents and basic compounds and pH control during the precursor preparation process.

Claims

1. Includes a compound represented by the following chemical formula 1, and Metal salt for a positive electrode active material precursor in the form of a non-spherical secondary particle solid solution in which nickel and manganese are homogeneously distributed to form a single phase: [Chemical Formula 1] (Ni a Mn b M 1 c )X In the above chemical formula 1, M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and X is SO4 or (NO3)2, and a, b, and c are each 0 <a<1, 0<b<1, 0≤c≤0.5이고, a+b+c=1을 만족한다.

2. In Claim 1, The compound represented by the above chemical formula 1 has the composition of the following chemical formula 1-1, and the metal salt for the positive electrode active material precursor is a metal salt for the positive electrode active material precursor in the form of a solid solution in which nickel, cobalt, and manganese are homogeneously distributed to form a single phase: [Chemical Formula 1-1] (Ni a1 Mn b1 What c1 M 2 d1 )X 1 In the above chemical formula 1-1, M 2 is one or more selected from the group consisting of Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and X 1 It is SO4 or (NO3)2, and a1, b1, c1, and d1 are 0.50≤a1<1, 0 respectively. <b1≤0.4, 0<c1≤0.4, 0≤d1≤0.1이고, a1+b1+c1+d1=1을 만족한다.

3. In Claim 1, A metal salt for an anode active material precursor, wherein the compound represented by the above chemical formula 1 has the composition of the following chemical formula 1-2: [Chemical Formula 1-2] (Ni a2 Mn b2 M 1 c2 )X 2 In the above chemical formula 1-2, M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and X 2 is SO4 or (NO3)2, and a2, b2, and c2 are each 0 <a2≤0.5, 0.5≤b2<1, 0≤c2<0.5이고, a2+b2+c2=1을 만족한다.

4. A step of preparing an aqueous transition metal solution by dissolving nickel raw material and manganese raw material in water; and The method includes the step of rapidly cooling the above transition metal aqueous solution to precipitate a solid precipitate, A method for manufacturing a metal salt for a positive electrode active material precursor, wherein the nickel raw material and the manganese raw material are each sulfates or nitrates of these metals.

5. In Claim 4, A method for preparing a metal salt for an anode active material precursor, wherein the step of preparing the above-mentioned transition metal aqueous solution is carried out at a temperature of 20°C or higher and below the boiling point, or under supercritical conditions.

6. In Claim 4, A method for manufacturing a metal salt for an anode active material precursor, wherein the rapid cooling described above lowers the temperature of the transition metal aqueous solution by more than 10°C within 1 second.

7. A positive active material precursor comprising a calcined body of a metal salt for a positive active material precursor according to claim 1.

8. In Claim 7, The above positive active material precursor comprises a compound represented by the following chemical formula 2: [Chemical Formula 2] (Ni a Mr b M 1 c )O2 In the above chemical formula 2, M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and a, b, and c are each 0 <a<1, 0<b<1, 0≤c≤0.5이고, a+b+c=1을 만족한다.

9. In Claim 7, The above precursor is a positive active material precursor in the form of a non-spherical secondary particle.

10. A positive electrode active material comprising a lithium composite transition metal oxide, which is a calcined body of a mixture of a positive electrode active material precursor and a lithium raw material according to claim 7.

11. In Claim 10, A positive electrode active material wherein the above lithium complex transition metal oxide has the composition of the following chemical formula 3 or chemical formula 4: [Chemical Formula 3] Li 1+x (Ni a3 Mr b3 M 1 c3 )O2 In the above chemical formula 3, M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and x, a3, b3, and c3 are -0.20≤x≤0.20, 0, respectively. <a3≤0.5, 0.5≤b3<1, 0≤c3<0.5이며, a3+b3+c3=1을 만족하며, [Chemical Formula 4] xLi2Mn (1-p) M 1 p O3·(1-x)LiNi q Mn r M 1 s O2 In the above chemical formula 4, M 1 is one or more selected from the group consisting of Co, Al, Ti, W, Mo, Nb, Cu, Fe, V, Cr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Mg, and B, and x, p, q, r, and s are each 0 <x<1.0, 0≤p≤0.5, 0<q<1.0, 0<r<1.0, 0≤s≤0.5이며, q+r+s=1을 만족한다.

12. In Claim 10, The above positive active material is a single-particle type positive active material comprising 50 or fewer nodules.

13. Anode comprising the anode active material of claim 10.

14. A lithium secondary battery comprising: a positive electrode according to claim 13; a negative electrode comprising a negative electrode active material; a separator interposed between the positive electrode and the negative electrode; and an electrolyte.

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