Transition metal precursor

Abstract

The present invention provides a transition metal precursor for preparing a positive electrode active material in the form of a secondary particle in which primary particles containing a transition metal are aggregated, wherein the secondary particle satisfies, in a pore distribution measured by a mercury (Hg) intrusion method, at least one of condition (A) in which the sum of areas of pores having a pore diameter of 0.001 μm to 0.01 μm is 0.05 m2 / g to 0.25 m2 / g and condition (B) in which the sum of volumes of the pores is 1×10-3 mL / g to 5×10-3 mL / g.

Description

Transition metal precursor

[0001] The present invention relates to a transition metal precursor, and more specifically, to a transition metal precursor for manufacturing a positive electrode active material in the form of secondary particles, wherein, in the pore distribution measured by the mercury intrusion method, the sum of the areas and / or sum of the volumes of pores having a specific pore diameter falls within a preset range, thereby providing a positive electrode active material with excellent electrochemical properties even without undergoing a cleaning process for removing residual lithium.

[0002] Lithium secondary batteries are devices that store electrical energy by utilizing the chemical potential difference between the positive and negative electrodes generated by the insertion and extraction of lithium ions within the lattice structure of the positive active material. Due to their advantages of low self-discharge rate, lightweight design, and excellent energy density, they are used as power devices for small devices such as mobile phones and power tools, as well as medium and large devices such as electric vehicles and large-scale ESS.

[0003] As the positive electrode active material of the above lithium secondary battery, a transition metal-based oxide that is structurally stable during the repeated insertion and extraction of lithium ions is used.

[0004] Residual lithium (Ex-Li) present on the surface of the cathode active material affects battery performance. + It hinders the diffusion of lithium, causing performance degradation, and induces the generation of CO2 and CO2 gases during charging and discharging under high voltage conditions, acting as a factor that degrades electrochemical characteristics such as capacity, rate characteristics, and cycle retention. The problem of residual lithium is particularly serious in Ni-based cathode active materials, which have a relatively high Ni content among transition metals.

[0005] For this reason, a washing process is required to remove residual lithium present on the surface, and this washing process is essential for High Ni products.

[0006] However, if a washing process is added, it leads to problems such as reduced productivity due to an increase in the number of manufacturing processes, additional water treatment costs, and regulatory issues regarding environmental concerns.

[0007] Therefore, there is a high need in the industry for new technology that can solve these problems all at once.

[0008] The present invention aims to solve the problems of the prior art described above and technical challenges that have been requested over time.

[0009] After conducting in-depth research and various experiments, the inventors of the present application confirmed that when a precursor is manufactured such that the sum of the pore areas and / or the sum of the volumes of pores with a specific pore diameter measured by the mercury intrusion method in a transition metal precursor of secondary particles satisfies specific conditions, it exhibits excellent electrochemical properties without undergoing a cleaning process to remove residual lithium and has a low sulfur content that causes poisoning in batteries, and thus completed the present invention.

[0010] Accordingly, the transition metal precursor according to the present invention is a transition metal precursor for manufacturing an anode active material in the form of secondary particles in which primary particles containing a transition metal are aggregated, wherein

[0011] In the pore distribution measured by the mercury (Hg) indentation method, the sum of the areas of pores having a pore diameter of 0.001 μm to 0.01 μm is 0.05 m 2 / g to 0.25 m 2 Condition (A) where / g and the sum of the volumes of the above workpieces is 1×10 -3 mL / g to 5×10 -3 It is characterized by satisfying at least one of the conditions (B) of mL / g.

[0012]

[0013] According to facts experimentally confirmed by the inventors of the present application, when a precursor has a high porosity at a specific pore diameter by having a pore diameter of 0.001 μm to 0.01 μm and a specific sum of area and / or volume, an electrochemically excellent positive active material can be manufactured without undergoing a washing process to remove residual lithium during the manufacturing process of the active material, and has the characteristic of having a low content of sulfur (S) and the like, which originate from the precursor raw material and cause poisoning in the secondary battery.

[0014] This may be because, when interpreted under conditions that do not affect the scope of the rights of the present invention, as the number of small pores increases, the contact area for reaction increases, and thus the amount of unreacted lithium raw material can be reduced during the mixing and calcination process with the lithium raw material for manufacturing the active material; consequently, compared to the prior art, the amount of lithium raw material mixed in the calcination process for manufacturing the active material can be reduced, and the amount of residual lithium generated is also reduced.

[0015]

[0016] The above mercury (Hg) intrusion method is generally based on the principle of mercury porosimetry, which measures porosity using the penetration of mercury. It utilizes the capillary phenomenon in which a liquid penetrates into fine pores; non-wetting liquids such as mercury only penetrate when external pressure is applied, and higher pressure is required as the pore size decreases. The measurement results are expressed as a function of the cumulative penetration volume of mercury depending on the pressure (or pore size). The diameter of the cylindrical pore penetrated at a given pressure is calculated using the following washburn equation:

[0017] R = -4γLVcosθ / P

[0018] In the above formula,

[0019] R is the pore diameter and;

[0020] γLV is the surface tension of a column of mercury (485 dynes / cm);

[0021] θ is the contact angle (130°) and;

[0022] P is the applied pressure (psi).

[0023] The method of performing the mercury intrusion method involves first placing a powder specimen with open pores into a capillary tube called a penetrometer, sealing it, applying a vacuum, and filling it with mercury. When pressure is applied to the penetrometer, mercury penetrates into the pores, causing the height of the mercury in the capillary tube to decrease; by measuring this decrease as a function of pressure, the volume of mercury that has penetrated into the pores can be determined. In other words, a mercury intrusion curve is obtained from the relationship between the pressure applied to the mercury and the amount of mercury intruded, and the result of mercury penetration can be expressed as the pore diameter or penetration pressure and the cumulative volume penetrated per mass of the specimen.

[0024] On the other hand, the nitrogen adsorption method measures the specific surface area (BET) of a material by placing a specimen in a tube, filling it with nitrogen gas, and utilizing the adsorption action where nitrogen adheres to the surface of the object; however, since it uses a gas with a small molecular size, such as nitrogen, it is only possible to measure relatively micropores. In contrast, the mercury intrusion method uses mercury, which exists as a liquid with a large molecular size at room temperature, allowing for the comparison of pore sizes that are relatively larger compared to nitrogen adsorption.

[0025] Therefore, the mercury intrusion method has a wider range of pore measurement compared to the nitrogen adsorption method (BET measurement). Consequently, the transition metal precursor of the present invention exhibits results similar to other general precursors during BET analysis, but is characterized by having a specific range of pore volume and pore area when measured by the mercury intrusion method.

[0026] Under conditions of identical or similar porosity, if there are many pores larger than the corresponding range, particle breakage becomes more severe during the press process, which is a mandatory step in the electrode manufacturing process, and may result in inferior high-temperature life characteristics. Therefore, having more fine pores than large pores allows for the prevention of excessive particle breakage while enabling the production of characteristics that increase capacity.

[0027] Under the above condition (A), the sum of the pore areas can be obtained using the relationship between the volume increase (dV) in the pore distribution range and the specific surface area (dA) increased in that range, dA = 4dV / Dav (Dav: average pore diameter), and the sum of the pore surface areas (ΣA) is calculated.

[0028] In the present invention, the sum of the areas of pores having a pore diameter of 0.001 μm to 0.01 μm is 0.05 m, as defined above. 2 / g to 0.25 m 2 Since it is in the range of / g, this is a larger value than other general precursors, and means that the precursor of the present invention has many pores with a pore diameter of 0.001 μm to 0.01 μm.

[0029] If the volume of the workpiece is expressed as an equation under the above condition (B), the volume of the workpiece (V) = πD 2 L / 4 (D: pore diameter, L: pore length), and the sum of the pore volumes is the sum of the pore volumes in a specific pore distribution range (0.001 μm ~ 0.01 μm).

[0030] In the present invention, the sum of the volumes of pores having a pore diameter of 0.001 μm to 0.01 μm is 1×10⁻⁶ as defined above. -3 mL / g to 5×10 -3 The range is mL / g, which is also a larger value than other general precursors, and means that the precursor of the present invention has many pores with a pore diameter of 0.001 μm to 0.01 μm.

[0031]

[0032] Controlling pores of these specific sizes to have a combined area or volume within the aforementioned range is possible in the manufacturing process of transition metal precursors by adjusting various process factors such as pH, stirring speed, stirring time, and temperature. For example, this can be controlled by changing the number of pH adjustments or the stirring speed during the co-precipitation process, and some examples regarding this can be found in the experimental details described later.

[0033]

[0034] In one specific example, in the pore distribution diameter measured by the above mercury (Hg) indentation method, the following Y may satisfy the condition 1≤Y≤5.

[0035] Y = [Sum of pore areas with a diameter of 1 μm to 5 μm / Sum of pore areas with a diameter of 0.001 μm to 0.01 μm].

[0036] The transition metal precursor of the present invention has a relatively small Y value because the sum of the pore areas having a pore diameter of 0.001 μm to 0.01 μm is larger compared to a general precursor. Preferably, it may be in the range of 1.5≤Y≤3.5.

[0037]

[0038] In another specific example, in the pore distribution diameter measured by the above mercury (Hg) indentation method, the following Z may satisfy the condition Z≥0.5.

[0039] Z = [Sum of pore volumes with a diameter of 0.001 μm to 0.01 μm / Sum of pore volumes with a diameter of 1 μm to 5 μm] × 100.

[0040] As described above, the transition metal precursor of the present invention has a pore volume sum of 0.001 μm to 0.01 μm with a pore diameter larger than that of a general precursor, so the Z value is relatively large. Preferably, Z can be in the range of ≥ 0.7.

[0041]

[0042] In one preferred example, in the pore distribution measured by the mercury (Hg) intrusion method, the rate of change (A) of the sum of the pore volumes below may be 0.50% to 1.00%.

[0043] Rate of change of sum of pore volumes (A) = [Sum of pore volumes with a pore distribution diameter of 0.01 μm to 0.1 μm / Sum of pore volumes with a pore distribution diameter greater than 0.1 μm (mL / g)] × 100.

[0044] The rate of change (A) of the sum of the pore volumes above represents the degree to which the sum of the pore volumes increases at diameters smaller than a specific pore diameter (0.1 μm). The transition metal precursor of the present invention has a large number of pores with small diameters and exhibits a characteristic in which the sum of the pore volumes increases rapidly at 0.1 μm or less, which can also be confirmed in the graph of FIG. 1.

[0045]

[0046] The transition metal precursor of the present invention has a larger surface area than a general precursor due to the large number of small pores, for example, BET of 17.5 m 2 It can be more than / g.

[0047] For similar reasons, the porosity measured by the mercury (Hg) intrusion method may be in the range of, for example, 40.0% to 45.0%.

[0048] The above porosity is a value expressed for the entire pore, not a specific pore diameter. If the porosity is too low, it may be difficult to achieve desired battery characteristics, such as capacity; conversely, if it is too high, side reactions may increase, which is undesirable.

[0049]

[0050] One of the effects of the transition metal precursor according to the present invention is that the sulfur (S) content, which causes poisoning in secondary batteries, is low, and for example, when measuring ICP, it can be 2,000 ppm or less.

[0051] Sulfur can originate from the raw materials of the precursor, such as Ni, Co, and Mn (NiSO4, CoSO4, MnSO4), and exhibits a relatively low sulfur content during the manufacturing process of the precursor.

[0052]

[0053] The present invention is particularly advantageous for precursors containing Ni as a transition metal. As previously explained, while such Ni-containing precursors require a cleaning process to remove residual lithium, which is a lithium byproduct, during the manufacturing process of active materials, the precursor of the present invention does not require such a cleaning process, thus offering a significant advantage in application.

[0054] In one specific example, such a precursor may have a composition of the following chemical formula in which the Ni content is 60 mol% or more based on the total transition metal content.

[0055] Ni x Co y Mn z M k (OH) 2+a

[0056] In the above formula,

[0057] M is at least one selected from the group consisting of Fe, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Al, Mo, Ga, W, Y, La, Ta and B, and

[0058] 0.6≤x≤1.0, 0≤y≤0.2, 0≤z≤0.4, 0≤k≤0.2, x+y+z+k=1, 0≤a≤0.5.

[0059]

[0060] In some cases, a predetermined amount of dopant may be added to the composition of the above chemical formula, and representative examples include Zr, Ti, W, B, P, Al, Mg Si, Zn, Sn, Ca, Ge, Ga, Nb, Mo, W, etc.

[0061] The above dopant may be more effective if it includes at least one element among Zr, Ti, W, B, P, Al, and Mg.

[0062] Zr enhances structural stability and thermal properties, and improves lifespan characteristics by suppressing structural collapse occurring at the particle surface through structural stabilization.

[0063] Ti can improve electrochemical properties and thermal stability, reduce structural instability such as side reactions with the electrolyte, and increase the surface protection effect of active material particles against electrolyte decomposition.

[0064] W has excellent conductivity and reacts with residual lithium to improve interfacial characteristics by reducing byproducts and suppressing interfacial reactions, and has the effect of improving the discharge capacity, output characteristics, and lifespan characteristics of lithium secondary batteries.

[0065] B improves structural stability by enhancing particle strength, has the effect of suppressing cracks occurring inside the particles during life evaluation, and can improve the ionic conductivity of the active material.

[0066] P has the effect of ensuring structural stability and improving the stability and lifespan characteristics of lithium secondary batteries by reducing residual lithium.

[0067] Al can improve surface resistance and lithium ion reactivity, Si can improve the thermal stability of the active material, and Mg can suppress phase changes of the active material and enhance the protective effect on the surface of the active material against electrolyte decomposition.

[0068]

[0069] In one preferred example, the transition metal precursor of the present invention may satisfy both condition (A) and condition (B).

[0070]

[0071] The present invention also provides a positive electrode active material prepared by calcining the transition metal precursor and the lithium raw material, and a lithium secondary battery comprising such positive electrode active material.

[0072] Calcination, which is a method for manufacturing positive electrode active materials, and lithium raw materials, which are raw materials for the same, are widely known in the art. Likewise, the composition and manufacturing method of lithium secondary batteries are also known in the art. Therefore, a detailed description thereof is omitted in this specification.

[0073] As explained above, the transition metal precursor according to the present invention can produce a positive electrode active material having electrochemical properties equivalent to or better than those without undergoing a cleaning process for removing residual lithium, and can provide a positive electrode active material with excellent performance because the sulfur content, which causes poisoning in secondary batteries, is relatively low.

[0074] Figure 1 is a graph showing the sum of pore areas in the range of pore diameters from 100 μm to 0.01 μm measured by the mercury intrusion method for the transition metal precursors of Example 1 and Comparative Examples 1 and 2 in Experimental Example 1.

[0075] The present invention will be described further below with reference to embodiments thereof, but the scope of the invention is not limited by them.

[0076]

[0077] [Example 1]

[0078] An aqueous solution of a nickel-cobalt-manganese hydroxide precursor was prepared by adding the nickel precursor NiSO4, the cobalt precursor CoSO4, and the manganese precursor MnSO4 to water in a molar ratio of 0.75:0.02:0.23, and an aqueous sodium hydroxide solution was added dropwise to the solution while stirring to allow the reaction to proceed. The reaction was carried out for 50 hours while adjusting the acidity in three stages (pH 13 - pH 11 - pH 13) within the pH range of 13 to 11. The reaction solution obtained after the reaction was further stirred for 5 hours, and the resulting aqueous precursor solution was neutralized to obtain the nickel-cobalt-manganese hydroxide, Ni 0.75 Co 0.02 Mn 0.23 After precipitating (OH)2, a precursor was obtained.

[0079] LiOH is mixed with the thus obtained precursor (nickel-cobalt-manganese hydroxide) to a Li / Me ratio of 1.2, and calcined at 800–830°C for 28 hours to produce LiNi 0.75 Co 0.02 Mn 0.23 O2 was manufactured.

[0080]

[0081] [Example 2]

[0082] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 1, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction mixture, and the reaction mixture was stirred for 5 hours while the pH was adjusted four times in a multi-stage manner. The precursor obtained in this way was calcined in the same manner as in Example 1 to prepare an anode active material.

[0083]

[0084] [Example 3]

[0085] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 1, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction mixture, and the pH was adjusted five times in a multi-stage manner while stirring for 5 hours. The precursor obtained in this way was calcined in the same manner as in Example 1 to prepare an anode active material.

[0086]

[0087] [Example 4]

[0088] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 1, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction mixture, and the pH was adjusted six times in multiple stages while stirring for 5 hours. The precursor obtained in this way was calcined in the same manner as in Example 1 to prepare an anode active material.

[0089]

[0090] [Example 5]

[0091] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 1, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to create a reaction mixture. During the stirring of the mixture for 5 hours, the pH was adjusted in three stages. LiOH was then mixed with the obtained precursor to achieve a Li / Me ratio of 1.1, and the mixture was calcined in the same manner as in Example 1 to produce an anode active material.

[0092]

[0093] [Example 6]

[0094] In the same manner as in Example 2, an aqueous solution of a nickel-cobalt-manganese hydroxide precursor was prepared, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to create a reaction mixture. During the stirring of the mixture for 5 hours, the pH was adjusted four times in a multi-stage manner. LiOH was then mixed with the obtained precursor to achieve a Li / Me ratio of 1.1, and the mixture was calcined in the same manner as in Example 2 to produce an anode active material.

[0095]

[0096] [Comparative Example 1]

[0097] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 1, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction mixture, and the pH was adjusted once in multiple stages while stirring for 5 hours. The precursor obtained in this way was calcined in the same manner as in Example 1 to prepare an anode active material.

[0098]

[0099] [Comparative Example 2]

[0100] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 1, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction mixture, and the pH was adjusted six times in multiple stages while stirring for 5 hours. The precursor obtained in this way was calcined in the same manner as in Example 1 to prepare an anode active material.

[0101]

[0102] [Comparative Example 3]

[0103] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 1, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction mixture, and the pH was adjusted seven times in multiple stages while stirring for 5 hours. The precursor obtained in this way was calcined in the same manner as in Example 1 to prepare an anode active material.

[0104]

[0105] [Comparative Example 4]

[0106] The precursor and the positive electrode active material were prepared in the same manner as in Example 1, except that the reaction mixture was stirred for 3 hours.

[0107]

[0108] [Comparative Example 5]

[0109] The precursor and the positive electrode active material were prepared in the same manner as in Example 1, except that the reaction mixture was stirred for 7 hours.

[0110]

[0111] [Comparative Example 6]

[0112] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 1, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction mixture, and the pH was adjusted once in multiple stages while stirring for 3 hours. The precursor obtained in this way was calcined in the same manner as in Example 1 to prepare an anode active material.

[0113]

[0114] [Comparative Example 7]

[0115] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 1, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction mixture, and the pH was adjusted once in multiple stages for 7 hours. The precursor obtained in this way was calcined in the same manner as in Example 1 to prepare an anode active material.

[0116]

[0117] [Comparative Example 8]

[0118] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 5, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction mixture, and the pH was adjusted seven times in multiple stages while stirring for 5 hours. The precursor obtained in this way was calcined in the same manner as in Example 5 to prepare an anode active material.

[0119]

[0120] [Comparative Example 9]

[0121] A nickel-cobalt-manganese hydroxide precursor aqueous solution was prepared in the same manner as in Example 6, and while stirring the aqueous solution, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction mixture, and the pH was adjusted six times in multiple stages while stirring for 5 hours. The precursor obtained in this way was calcined in the same manner as in Example 6 to prepare an anode active material.

[0122]

[0123] [Experimental Example 1]

[0124] For the precursors prepared in Examples 1 to 6 and Comparative Examples 1 to 9, respectively, tap density and particle size were measured, and porosity, BET, and ICP were measured using the following measurement conditions and are shown in Table 1. Although specific equipment and conditions were used for the experiment, this is merely an experiment for the description of the present invention, and it should be understood that the scope of the present invention is not limited by the following conditions.

[0125]

[0126] Measurement conditions for porosity by mercury intrusion method

[0127] Pretreatment was performed at 100°C for 60 minutes and at 300°C for 120 minutes, and porosity was measured by gradually increasing the pressure from 0 to 60,000 psia using Micromeritics’ AutoPore V 9620.

[0128]

[0129] BET Specific Surface Area Measurement Conditions

[0130] Measurements were taken using Micromeritics’ Tristar II 3020, and Vacprep061 was used as the pretreatment device.

[0131] The specific surface area value was measured by pre-treating with a pre-treatment device at 100°C for 60 minutes and at 300°C for 120 minutes, and measuring the adsorption amount using a BET measuring device at liquid nitrogen temperatures (-77K, -195.8°C) and relative pressure (P / P0) in the range of 0.05-0.3.

[0132]

[0133] ICP measurement

[0134] The sulfur (S) content in the precursor was measured using an ICP-OES (OPTIMA 7300) instrument.

[0135]

[0136] Referring to the results of Table 1 above, first, the porosity represents the pores of the overall pore distribution. If the porosity is too high, side reactions increase, and if the porosity is too low, the desired cell evaluation results may not be obtained. Therefore, it can be seen that the precursors of the examples are in the range of approximately 40.0% to 45.0%.

[0137] Compared to the comparative examples, the precursors of the examples have a significantly lower sulfur content and a very high BET due to the high porosity.

[0138]

[0139] Based on the measurement results of Table 1 above, the sum of the work area and the sum of the work volume were calculated and are shown in Table 2 below.

[0140]

[0141] Based on the results of Table 2 above, the following facts can be confirmed.

[0142]

[0143] First, the transition metal precursors of the examples have a pore area sum of 0.05 m² with a pore diameter of 0.001 μm to 0.01 μm. 2 / g to 0.25 m 2 While it falls within the range of / g, the transition metal precursors of the comparative examples are 0.047 m 2 It can be seen that it is less than / g.

[0144]

[0145] Second, the transition metal precursors of the examples have a pore volume sum of 1×10⁻⁶ with a pore diameter of 0.001 μm to 0.01 μm. -3 mL / g to 5×10 -3 While the transition metal precursors of the comparative examples fall within the range of mL / g, the comparative examples are 6×10 -4 It can be seen that it is less than mL / g.

[0146]

[0147] Third, regarding Y, which is the ratio of the sum of the pore areas with a diameter of 1 μm to 5 μm to the sum of the pore areas with a diameter of 0.001 μm to 0.01 μm, it can be seen that the transition metal precursors of the examples fall within the range of 1 to 5, while the transition metal precursors of the comparative examples have a very large value.

[0148]

[0149] Fourth, regarding Z, which is the percentage of the sum of the pore volumes with a pore diameter of 0.001 μm to 0.01 μm to the sum of the pore volumes with a pore diameter of 1 μm to 5 μm, it can be seen that the transition metal precursors of the examples fall within a range of 0.5 or higher, while the transition metal precursors of the comparative examples have a very small value.

[0150]

[0151] Fifth, regarding A, which is the percentage of the sum of pore volumes with a pore distribution diameter of 0.01 μm to 0.1 μm relative to the sum of pore volumes with a pore distribution diameter greater than 0.1 μm, it can be seen that the transition metal precursor of the example falls within the range of 0.5 to 1, while the transition metal precursor of the comparative example has a smaller value.

[0152]

[0153] For reference, the sum of the pore areas in the range of pore diameters from 100 μm to 0.01 μm was measured by the mercury intrusion method for the transition metal precursors of Example 1 and Comparative Examples 1 and 2, and is shown in Fig. 1.

[0154] As shown in Figure 1, it can be seen that the precursor of Example 1 shows a tendency for the sum of the pore areas of 0.1 μm or less to increase compared to the precursors of Comparative Examples 1 and 2.

[0155]

[0156] [Experimental Example 2]

[0157] A positive electrode active material paste was prepared by mixing the positive electrode active materials prepared in Examples 1 to 4 and Comparative Examples 1 to 6, respectively, with Super-P as a conductive material, PVdF as a binder, and N-methylpyrrolidone as a solvent in a ratio of 96.5:1.5:2 (weight ratio). The positive electrode active material paste was coated onto an aluminum current collector, dried at 120°C, and then rolled to produce a positive electrode.

[0158] An electrode assembly was manufactured by using Li metal as the negative electrode and interposing a porous polyethylene film as a separator between them, and after placing the electrode assembly inside a battery case, an electrolyte was injected into the battery case to manufacture a lithium secondary battery. At this time, as the electrolyte, a 1.0 M concentration of lithium hexafluorophosphate (LiPF6) was dissolved in an organic solvent to which vinylene carbonate (VC 2 wt%) was added to ethylene carbonate / dimethyl carbonate / diethyl carbonate (mixed volume ratio of EC / DMC / DEC = 1 / 2 / 1).

[0159] The battery charge-discharge performance of the secondary batteries fabricated above was measured. Specifically, the capacity evaluation was based on 200 mAh / g at a 0.1C rate, and the charge-discharge conditions were performed in a constant current (CC) / constant voltage (CV) range of 4.25 to 2.5 Voltage. The results of the charge-discharge measurements are shown in Table 3 below.

[0160]

[0161] As shown in Table 3 above, the secondary batteries of the examples are significantly superior in capacity and charge / discharge efficiency compared to the comparative examples, and the resistance (DCIR) is relatively small, so it can be seen that they exhibit excellent electrochemical characteristics overall.

[0162]

[0163] The present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without changing the technical concept or essential features of the invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. A transition metal precursor for manufacturing an anode active material in the form of secondary particles aggregated from primary particles containing a transition metal, wherein In the pore distribution measured by the mercury (Hg) indentation method, the sum of the areas of pores having a pore diameter of 0.001 μm to 0.01 μm is 0.05 m 2 / g to 0.25 m 2 Condition (A) where / g and the sum of the volumes of the above workpieces is 1×10 -3 mL / g to 5×10 -3 A transition metal precursor characterized by satisfying at least one of the conditions (B) of mL / g.

2. A transition metal precursor according to claim 1, characterized in that, in the pore distribution diameter measured by the mercury (Hg) indentation method, the following condition Y satisfies 1 ≤ Y ≤ 5: Y = [Sum of pore areas with a diameter of 1 μm to 5 μm / Sum of pore areas with a diameter of 0.001 μm to 0.01 μm].

3. A transition metal precursor according to claim 1, characterized in that, in the pore distribution diameter measured by the mercury (Hg) indentation method, the following Z satisfies the condition Z≥0.5: Z = [Sum of pore volumes with a diameter of 0.001 μm to 0.01 μm / Sum of pore volumes with a diameter of 1 μm to 5 μm] × 100.

4. A transition metal precursor according to claim 1, characterized in that, in the pore distribution measured by the mercury (Hg) indentation method, the rate of change (A) of the sum of the following pore volumes is 0.50% to 1.00%: Rate of change of sum of pore volumes (A) = [Sum of pore volumes with a pore distribution diameter of 0.01 μm to 0.1 μm / Sum of pore volumes with a pore distribution diameter greater than 0.1 μm (mL / g)] × 100.

5. In claim 1, BET is 17.5 m 2 A transition metal precursor characterized by having a value of / g or more.

6. A transition metal precursor according to claim 1, characterized in that the porosity measured by the mercury (Hg) indentation method is 40.0% to 45.0%.

7. A transition metal precursor according to claim 1, characterized in that the S content is 2,000 ppm or less when measured via ICP.

8. A transition metal precursor according to claim 1, characterized by including Ni as the transition metal.

9. A transition metal precursor according to claim 1, characterized by having a composition of the following chemical formula: Ni x What y Mn z M k (OH) 2+a In the above formula, M is at least one selected from the group consisting of Fe, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Al, Mo, Ga, W, Y, La, Ta and B, and 0.6≤x≤1.0, 0≤y≤0.2, 0≤z≤0.4, 0≤k≤0.2, x+y+z+k=1, 0≤a≤0.

5.

10. A transition metal precursor according to claim 1, characterized by satisfying both condition (A) and condition (B).

11. A positive electrode active material characterized by being manufactured by calcining a transition metal precursor and a lithium raw material according to claim 1.

12. A lithium secondary battery characterized by including a positive electrode active material according to claim 11.

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