KR102328126B1 - Lithium compound, nickel-based positive active material, method of preparing lithium oxide, mehtod of preparing nickel-based positive active material, and secondary battery using the same - Google Patents

Abstract

To a lithium compound, a nickel-based positive active material, a method for manufacturing lithium oxide, a method for manufacturing a nickel-based positive electrode active material, and a secondary battery using the same, Li ₂ O primary particles having an average particle diameter (D50) of 5 μm or less; and secondary particles composed of the primary particles.

Description

Lithium compound, nickel-based positive electrode active material, production method of lithium oxide, nickel-based positive electrode active material production method, and secondary battery using the same POSITIVE ACTIVE MATERIAL, AND SECONDARY BATTERY USING THE SAME}

To a lithium compound, a nickel-based positive electrode active material, a method for manufacturing lithium oxide, a method for manufacturing a nickel-based positive electrode active material, and a secondary battery using the same.

In the case of a lithium secondary battery, the energy density is high, and when compared with the same volume, the lithium secondary battery has 1.5 to 2 times higher energy density than that of a Ni/Cd battery. As a portable product, their performance is determined by a secondary battery, which is a main component, and therefore, a need for a high-performance battery is emerging. Battery performance is required for high-efficiency characteristics, stability at high temperatures, lifespan, and charging/discharging characteristics.

In particular, as cells are connected in parallel, overdischarge is highlighted as an important factor in a lithium secondary battery.

Currently, in most markets, lithium metal oxide as a positive electrode and a lithium secondary battery based on carbon as the negative electrode are used. In general, the lifetime efficiency of a lithium metal oxide-based positive electrode material is higher than that of a carbon-based negative electrode material.

In such an environment, the more frequent the overdischarge, the more side reactions occur at the cathode, which eventually leads to a short circuit of the parallel cell. As a method for solving this problem, there is a method of increasing the efficiency of the anode or adjusting the efficiency of the anode to the cathode, but there are many obstacles to increasing the efficiency of the cathode. _{Accordingly, lithium nickel oxide (Li 2} NiO ₂ ) having an orthorhombic Immm structure is being studied as a typical positive electrode additive as a positive electrode additive to match the efficiency of the positive electrode to the negative electrode.

However, lithium oxide, a precursor of lithium nickel oxide, has a disadvantage in that it is expensive. To solve this problem, a lithium nickel oxide manufacturing process using lithium hydroxide, lithium carbonate, and lithium nitrate as a precursor has been studied. There is this situation.

Specifically, perlithium transition metal oxide is synthesized by heat-treating by mixing the raw material transition metal oxide MOx (NiO, CoO, FeO, MnO, etc.) and the reaction equivalent or more than the reaction equivalent lithium oxide (Li _{2 O).}

If the mixed transition metal oxide and lithium oxide (Li ₂ O) do not completely react in the synthesis of the perlithium transition metal oxide, the irreversible capacity, reversible capacity, and reversible efficiency decrease in the electrochemical reaction of the perlithium transition metal oxide and the anode There is a problem of shortening the battery life.

In addition, in the battery manufacturing process, clogging of the slurry and poor electrode coating due to the solidification of the liquid electrode slurry may occur.

After the battery is constructed, problems such as gas generation due to electrolyte decomposition reaction, battery life reduction and explosion due to battery swelling, and deterioration of high temperature stability of the battery may occur.

The lithium transition metal oxide synthesized by an incomplete reaction is not easy to detect, and there is a problem that a complete reaction is not achieved even after re-sintering. When lithium oxide (Li ₂ O) is added, an excess of lithium is supplied. This can exacerbate the problems listed above.

Accordingly, since the particle size and shape of the lithium transition metal oxide are determined by the physical properties of the transition metal oxide, changing the physical properties of the transition metal oxide is limited.

Accordingly, in order to improve the incomplete reaction of the lithium transition metal oxide, it is necessary to improve the miscibility and reactivity of _{lithium oxide (Li 2 O) with the transition metal oxide.}

In one embodiment of the present invention, the shape of lithium oxide may be adjusted to a spherical shape in order to improve the degree of mixing with the transition metal oxide.

In order to facilitate adsorption on the surface of the transition metal oxide during the mixing process, lithium oxide is composed of small primary particles of 5 μm or less. Lithium oxide composed of fine particles has a large specific surface area, which increases reactivity. More specifically, it may be composed of particles of 1 μm or less.

* The fine primary particles float easily, resulting in poor process workability, large material loss, and agglomeration of lithium oxide powders due to electrostatic force, resulting in low miscibility. Therefore, it is preferable that the fine primary particles are aggregated to form secondary particles having a size similar to that of the transition metal oxide.

Lithium oxide in the form of secondary particles is pulverized during mixing with the transition metal oxide to be uniformly distributed on the surface of the transition metal oxide.

Impurities contained in lithium oxide cause a eutectic reaction with lithium oxide to lower the dissolution temperature of lithium oxide and ultimately increase the reactivity of lithium oxide. .

Hereinafter, the improved lithium oxide will be described in detail.

_{In one embodiment of the present invention, Li 2} O primary particles having an average particle diameter (D50) of 5 μm or less; and secondary particles composed of the primary particles. The lithium compound may be lithium oxide. The description of the purpose and effect of the primary particles and the secondary particles is the same as described above.

The secondary particles may be spherical. Lithium oxide currently on the market is not spherical, but a particle composition of various shapes. It is possible to achieve improved reactivity with transition metal oxides from a uniform spherical shape.

More specifically, the average particle diameter (D50) of the secondary particles may be 10 to 100㎛. Alternatively, the average particle diameter (D50) of the secondary particles may be 10 to 30㎛. This may be adjusted according to the size of the selected transition metal oxide.

_{In another embodiment of the present invention, a lithium compound comprising Li 2} O primary particles having an average particle diameter (D50) of 5 μm or less and secondary particles consisting of the primary particles; and a nickel raw material; provides a nickel-based positive electrode active material derived from.

The positive active material may be Li ₂ NiO ₂ , and Dmin may be 5 μm or more.

The positive active material may have a residual lithium compound of 2.5% by weight or less based on 100% by weight of the total weight. This is due to the characteristics of the lithium raw material as described above. Residual lithium properties can be improved due to the improved reactivity of lithium oxide in the form of secondary particles.

1 is a schematic flowchart of a method for producing lithium oxide according to an embodiment of the present invention.

Specifically, it is prepared in two steps: a wet reaction of a lithium hydroxide raw material and a high-temperature decomposition reaction in a low-oxygen atmosphere.

Step 1: 2LiOH-xH ₂ O + H ₂ O ₂ -> Li ₂ O ₂ + yH ₂ O, x is an integer greater than or equal to 0.

Step 2: Li ₂ O ₂ -> Li ₂ O + 1/2 O ₂ (g)

The schematic synthesis method of each step is as follows. In each process, it is desirable to maintain an inert atmosphere in order to prevent contamination by _{atmospheric moisture and CO 2 and promote material conversion.}

Lithium hydroxide monohydrate or lithium hydroxide-containing lithium raw material and hydrogen peroxide solution mixing step

The theoretical reaction ratio of lithium hydroxide and hydrogen peroxide is 2:1, but the ratio can be adjusted to improve the reaction yield. This will be described later.

As a raw material, lithium hydroxide monohydrate (LiOH-H ₂ O), lithium hydroxide anhydride (LiOH), or lithium hydroxide polyhydrate (LiOH-xH ₂ O) can be used. In order to improve the reaction yield, it is preferable to use lithium hydroxide anhydride.

Hydrogen peroxide can be used as an aqueous solution (H ₂ O ₂ -zH ₂ O, z is an integer greater than or equal to 0). In order to improve the reaction yield, it is preferable to use pure hydrogen peroxide, but it is preferable to use an aqueous solution having a concentration of 35% for storage and safety reasons.

Perlithium oxide precipitation and shape control step

By controlling the shape of the reactor, the shape and dimension of the inner baffle and the impeller, the number of impeller rotations, the reactor temperature, etc., the Li ₂ O ₂ intermediate material particle size and shape produced can be controlled. As the impeller rotation speed increases, the average particle size decreases and spherical particles are formed.

The higher the reactor temperature, the larger the average particle size, and the shape may change from spherical to amorphous.

The reaction time may be 1 minute or more after the input of the raw material, and 30 to 60 minutes may be suitable.

It is not necessary to control the temperature of the reactor, but it is preferable to control it within the range of 30 to 60° C. in order to control the reaction rate.

Recovery and drying of the prepared slurry precipitate

It is possible to separate the solution and the solid content by sedimentation of the prepared slurry, passing through a filter, centrifugation, or the like. The recovered solution is an aqueous solution of lithium hydroxide in which an excess of lithium is dissolved, which can be used to prepare a lithium compound. The recovered Li ₂ O ₂ solid content may be dried by vacuum drying the surface adsorbed water.

Heat treatment in low oxygen atmosphere furnace

The recovered solid content is converted to _{Li 2} O ₂ in an inert atmosphere or high temperature in a vacuum atmosphere as Li _{2 O 2 .} The conversion temperature is possible at 300°C or higher, preferably 400°C to 600°C.

Li ₂ O Powder recovery and packaging

Nitrogen filling and vacuum packaging are preferred to prevent denaturation in the atmosphere.

In particular, there is a risk of degeneration into lithium hydroxide and lithium carbonate when in contact with atmospheric moisture and CO _{2 at the same time.}

Hereinafter, a manufacturing method according to an embodiment of the present invention will be described in detail.

In another embodiment of the present invention, hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) to react to obtain a lithium peroxide (Li ₂ O ₂ ); and heat-treating the perlithium oxide to obtain lithium oxide (Li ₂ O), including, _{by reacting the hydrogen peroxide (H 2} O ₂ ) and lithium hydroxide (LiOH) with perlithium oxide (Li ₂ O ₂ ) In the step of obtaining; in the molar ratio of lithium in lithium hydroxide to hydrogen peroxide (Li/H ₂ O ₂ ) It provides a method for producing lithium oxide that would be 1.9 to 2.4.

In the step of reacting the hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) to obtain a lithium peroxide (Li ₂ O ₂ ); in, the reaction temperature may be 40 to 60 °C.

The hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) are reacted to obtain a lithium peroxide (Li ₂ O ₂ ); in, hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) are reacted at 500 rpm More agitation may be accompanied.

The heat treatment of the lithium peroxide to obtain lithium oxide (Li ₂ O); may be performed at 400 to 600° C. in an inert atmosphere.

For conditions such as the molar ratio, reaction temperature, and stirring, the meaning of the ranges will be specifically described in Examples and Experimental Examples to be described later.

In another embodiment of the present invention, hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) by reacting to obtain a lithium peroxide (Li ₂ O ₂ ); heat-treating perlithium oxide to obtain lithium oxide (Li ₂ O); and calcining the lithium oxide and the nickel raw material to obtain a nickel-based positive electrode active material; including, _{by reacting hydrogen peroxide (H 2} O ₂ ) and lithium hydroxide (LiOH) to produce lithium peroxide (Li ₂ O ₂ ) In the obtaining; in, the molar ratio of lithium in lithium hydroxide to hydrogen peroxide (Li/H ₂ O ₂ ) is 1.9 to 2.4 to provide a method for producing a nickel-based positive electrode active material.

_{In another embodiment of the present invention, a lithium compound comprising Li 2} O primary particles having an average particle diameter (D50) of 5 μm or less and secondary particles consisting of the primary particles; and a nickel raw material; a positive electrode comprising a nickel-based positive electrode active material resulting from; a negative electrode including an anode active material; and an electrolyte positioned between the positive electrode and the negative electrode.

Compared to the conventional Li ₂ O, the conversion rate is increased in the nickel-based lithium oxide synthesis process, and thus an increase in electrochemical capacity, a decrease in residual lithium content, and an increase in material efficiency can be expected.

1 is a schematic flowchart of a method for producing lithium oxide according to an embodiment of the present invention.
2 is an SEM photograph of the particle shape according to the results of Experiment 2.
3 is a particle SEM photograph of Experiment 3.
4 is a schematic diagram of a co-precipitation reactor used in Examples of the present invention.
5 is an SEM photograph of particles according to Experiment 4.
6 is a schematic diagram of a furnace designed for _{Li 2 O production.}
7 is an SEM photograph after mixing the raw materials in Experiment 6, and FIG. 8 is an SEM photograph of LNO synthesized after sintering.
9 is a charge-discharge curve of the coin cell manufactured in Experiment 6.
10 is an SEM photograph of commercially available Li ₂ O (left) and an SEM photograph of _{Li 2 O according to the present embodiment.}

Hereinafter, embodiments of the present invention will be described in detail. However, this is provided as an example, and the present invention is not limited thereto, and the present invention is only defined by the scope of the claims to be described later.

1. Li/H ₂ O ₂ ratio, temperature experiment

Experimental method

After adding LH powder and H ₂ O ₂ , the stirring reaction was started, and the reaction time was 60 minutes.

_{Li 2} O ₂ powder was recovered by a vacuum sieving device. The recovered powder was dried in a vacuum oven at 130° C. for 3 hours. After XRD measurement, the powder was quantitatively analyzed by Rietveld refinement method. (Using Panalytic's highscore plus program)

Yi ₂ O ₂ Yield = (Li ₂ O _{2 Acquisition Amount)/(Li 2} O ₂ Acquisition Amount when input Li raw material is converted to 100%), Temperature is set temperature, actual temperature may be 2~3℃ lower

Table 1 below shows the results for the purity of the _{synthesized powder Li 2} O _{2 .}

Li/H ₂ O ₂ LiOH-H ₂ O H ₂ O ₂
(34.5%) Li ₂ O ₂ Purity [wt%] [mol/mol] [g] [g] Temperature (℃) 25 40 50 60 70 80 1.4 70 117 65.3 98.6 98.4 93.3 90.5 98.3 1.6 80 117 61.5 99 97 95.6 91.7 98.7 1.7 85 117 68.2 96.8 97.4 97.7 95.1 97 1.8 90 117 78.7 96.4 95.9 98 91.9 97.2 1.9 95 117 90.8 98.4 96.3 98.3 93.2 96.9 2.2 110 117 97.4 97.4 96.1 97.2 89.1 90.9 2.4 120 117 97.1 96.4 95.4 96.5 84.3 94.7 2.6 130 117 97.3 94.3 94.4 95.1 89.2 93.4 2.8 140 117 59.1 84.6 80.2 94.4 83.5 77.7 3.0 150 117 72.2 61.6 61.2 87.9 67.3 65.9

Table 2 below is the weight of the synthesized dry powder. Theoretically, it is a value that needs to be compared with the amount _{of Li 2} O ₂ obtained when 100% converted. The powder made _{is not 100% Li 2} O ₂ , so simply having a lot of weight is not a good thing.

Li/H ₂ O ₂ LiOH-H ₂ O H ₂ O ₂
(34.5%) Synthesized Li ₂ O ₂ Weight [g], dry powder theory
Li ₂ O ₂ amount [mol/mol] [g] [g] Temperature (℃) [g] 25 40 50 60 70 80 1.4 70 117 30.816 25.43 27.6 25.66 27.84 24.71 38.3 1.6 80 117 29.896 29.62 31.53 29.63 31.4 29.3 43.7 1.7 85 117 33.776 31.49 34.14 31.24 34.44 34.9 46.5 1.8 90 117 35.597 33.77 35.53 34.84 38.09 36.39 49.2 1.9 95 117 33.804 34.56 38.69 37.59 40.47 38.43 51.9 2.2 110 117 40.18 43.44 46.44 45.25 47.98 46.99 60.1 2.4 120 117 44.42 47.28 48.98 48.77 50.73 50.34 65.6 2.6 130 117 45.53 50.16 52.7 51.73 53.31 50.99 71.1 2.8 140 117 61.53 53.22 54.83 53.15 55.61 59.46 76.5 3.0 150 117 57.88 56.73 61.4 60.19 59.22 57.32 82.0

From the results of Tables 1 and 2, the _{yield of Li 2} O ₂ can be calculated, and the results are shown in Table 3 below. Specifically, after multiplying the result of Table 1 and the result of Table 2, it was divided by the theoretical Li ₂ O ₂ amount of Table 2 to obtain Table 3.

Li/H2O2 LiOH-H2O H2O2
(34.5%) Li2O2 yield [%] [mol/mol] [g] [g] Temperature (℃) 25 40 50 60 70 80 1.4 70 117 52.6 65.5 71.0 62.6 65.8 63.5 1.6 80 117 42.0 67.1 69.9 64.8 65.8 66.1 1.7 85 117 49.6 65.6 71.6 65.7 70.5 72.9 1.8 90 117 56.9 66.2 69.3 69.4 71.1 71.9 1.9 95 117 59.1 65.5 71.7 71.1 72.6 71.7 2.2 110 117 65.1 70.4 74.2 73.1 71.1 71.0 2.4 120 117 65.7 69.5 71.2 71.7 65.2 72.7 2.6 130 117 62.3 66.6 70.0 69.2 66.9 67.0 2.8 140 117 47.5 58.8 57.5 65.6 60.7 60.4 3.0 150 117 51.0 42.6 45.8 64.5 48.6 46.1

At a low temperature, since LH is precipitated and is not converted _{to Li 2} O ₂ , it was found that the purity of _{Li 2} O _{2 decreased.} At high temperature, H ₂ O ₂ was decomposed and the _{purity of Li 2} O ₂ was decreased. When the Li/H ₂ O ₂ ratio is low, it _{is expected that the dissolution loss in H 2} O ₂ is high, so that the Li ₂ O ₂ production yield is low. If the Li/H ₂ O ₂ ratio is high, it is expected that LH will precipitate and the Li ₂ O _{2 purity will decrease.}

The optimal ratios derived therefrom are shown in Table 4 below.

variable temperature range Li/H ₂ O ₂ molar ratio Optimal synthesis range 40~60℃ 1.9~2.4

2. Reaction time experiment

_{Li 2} O ₂ was precipitated by controlling the reaction time in various ranges as shown in Table 5 below at 60°C. The specific method is the same as in Experiment 1 described above.

reaction time XRD analysis (wt%) particle size observation Li ₂ O ₂ D50 [um] 10 min. 98.6 90 30 min. 97.5 90 60 min. 98.3 100 90 min. 99.1 90 "+60min. waiting" 97.7 105

2 is an SEM photograph of the particle shape according to the results of Experiment 2. At 60°C, it can be seen that the reaction was completed in a short time within 10 minutes. After waiting for 60 minutes, the purity decreased. The longer the waiting time, the lower the _{Li 2} O _{2 purity.} It is expected that this is because LiOH increases due to decomposition of hydrogen peroxide. There was almost no difference in particle size and shape.

Table 6 below is the conclusion of Experiment 2.

variable reaction time Temperature Optimal synthesis range 10 to 90 minutes irrelevant

3. Reactor rpm effect experiment

The shape change according to the reactor rpm was observed. _{Li 2} O ₂ of 98% or more purity was synthesized regardless of the rpm. 3 is a particle SEM photograph of Experiment 3.

There was no shape change above 500rpm. At 150 rpm, it can be seen that the particle size is non-uniform.

If the rpm is controlled to 500 or more, it is expected that the desired effect can be obtained.

4. Synthesis experiment using coprecipitation reactor

4 is a schematic diagram of a co-precipitation reactor used in Examples of the present invention.

_{More specifically, Li 2} O ₂ was synthesized using a co-precipitation reactor used for synthesizing a secondary battery cathode precursor. The shapes of the reactor and the impeller are shown in FIG. 4 .

In order to shorten the reaction time, the injection method of hydrogen peroxide was changed.

Although quantitative input is the basic method, hydrogen peroxide solution was manually added to shorten the reaction time and then reacted by inputting it with a metering pump.

The results are shown in Table 7 below.

rpm LiOH-H ₂ O (98.5%) H ₂ O ₂ (34.5%) D=80cm, T=10cm H ₂ O ₂ Dosing method and reaction time Li ₂ O ₂ Li ₂ O Li ₂ O ₂ water note [kg] [kg] T. Vel. [m/sec] min D50 [um] D50 [um] [wt%] 150 3 3.4 0.785 Quantitative dosing (15 minutes) + 60 minutes reaction) 50 35 98.6 a 500 3 3.4 2.618 Quantitative dosing (15 minutes) + 60 minutes reaction) 30 21 97.5 b 750 3 3.4 3.927 Quantitative dosing (15 minutes) + 60 minutes reaction) 20 14 98.3 c 750 5.2 6 3.927 Quantitative dosing (40 minutes) + 60 minutes reaction 25 17.5 98.4 d 750 5.2 6 3.927 After 2kg injection, quantitative injection (15 minutes) + 60 minutes reaction 20 14 98.3 e

5 is an SEM photograph of particles according to Experiment 4. As a result of using the coprecipitation reactor, it can be seen that the sphericity of the particles increases.

In addition, it can be seen that the higher the rpm, the smaller the D50 of the secondary particles. (compare a, b, c)

It can be seen that when H ₂ O ₂ is slowly added in a quantitative manner, the particles become larger. (Compare d and e)

It is expected that the particle size can be controlled by adjusting the reaction rate and rpm.

5. Preparation of lithium oxide

_{Li 2} O ₂ synthesized in Experiment 4 was converted to _{Li 2} O by heat treatment at 420° C. for 3 hours in a nitrogen atmosphere. The converted components are shown in Table 8 below.

rpm LiOH-H ₂ O (98.5%) H ₂ O ₂ (34.5%) D=80cm, T=10cm H ₂ O ₂ Dosing method and reaction time Li ₂ O ₂ Li ₂ O ₂ water Li ₂ O Li ₂ O purity note [kg] [kg] T. Vel. [m/sec] min D50 [um] [wt%] D50 [um] [wt%] 150 3 3.4 0.785 Quantitative dosing (15 minutes) + 60 minutes reaction) 50 98.6 35 97.9% a 500 3 3.4 2.618 Quantitative dosing (15 minutes) + 60 minutes reaction) 30 97.5 21 96.2% b 750 3 3.4 3.927 Quantitative dosing (15 minutes) + 60 minutes reaction) 20 98.3 14 97.4% c 750 5.2 6 3.927 Quantitative dosing (40 minutes) + 60 minutes reaction 25 98.4 17.5 97.6% d 750 5.2 6 3.927 After 2kg injection, quantitative injection (15 minutes) + 60 minutes reaction 20 98.3 14 97.4% e

It can be seen that the particle size and shape are _{affected by Li 2} O _{2 .}

Additionally, a furnace as shown in FIG. 6 was manufactured and heat-treated.

After charging 10 g of Li ₂ O ₂ inside, the heat treatment was started while flowing _{N 2} after removing the internal air with a vacuum pump for 30 minutes. After completion of the heat treatment, the powder was discharged and cooled in a nitrogen atmosphere to recover.

The flow rate of nitrogen during heat treatment varied from 1 to 5 L per minute, and there was no difference according to the flow rate.

Table 9 below shows the heat treatment results.

temp (℃) time (min.) Li ₂ O ₂ [wt%] Li ₂ O[wt%] LiOH [wt%] LiOH-H ₂ O[wt%] Li ₂ CO ₃ [wt%] 350 30 97.3 2.2 0 0.5 0 350 60 93.8 6.1 0 0.2 0 350 90 84.6 15.1 0 0.3 0 350 120 79.6 20 0 0.4 0 400 30 31.9 67.4 0 0.5 0.2 400 60 0.1 99.4 0 0.3 0.2 400 90 0.2 99 0 0.5 0.3 400 120 0 99.7 0 0.3 0 450 30 0 99.6 0 0.4 0 450 60 0 99.6 0 0.4 0 450 90 0 99.7 0 0.3 0 450 120 0 99.8 0 0.2 0 500 30 0 99.6 0 0.4 0 500 60 0 99.7 0 0.3 0 500 90 0 99.8 0 0.2 0 500 120 0 99.8 0 0.2 0 600 30 0 99.5 0 0 0.5 600 60 0 99.6 0 0.4 0 600 90 0 99.2 0 0.8 0

As shown in Table 9, complete conversion _{to Li 2} O is possible during heat treatment at a temperature of 400° C. or higher for 60 minutes or longer.

* 6. LNO synthesis and cell data analysis

20 g of NiO and 8.85 g of prepared Li ₂ O were mixed for 5 minutes using a small mixer. _{Li 2} O used at this time is sample c of Table 8.

The mixed powder was exposed at 700° C. for 12 hours in a nitrogen atmosphere to synthesize _{Li 2} NiO _{2 .} The synthesized powder was 28.86 g.

7 is an SEM photograph after mixing, and FIG. 8 is an SEM photograph of LNO synthesized after sintering.

A CR2032 coin cell was prepared using the prepared Li ₂ NiO ₂ , and its electrochemical properties were evaluated. The electrode was coated with an active material layer to a thickness of 50 to 80 μm on an aluminum thin plate having a thickness of 14 mm.

The electrode slurry was _{mixed with Li 2} NiO ₂ : Denka Black (DB): PvdF = 85:10:5 wt%, and the prepared electrode was vacuum dried and then pressed under pressure, and the thickness of the final coating layer was 40-60 μm. _{The electrolyte is an organic solution in which LiPF 6} salt is dissolved at a concentration of 1M in EC:EMC=1:2 solvent.

The prepared coin cell was charged and discharged in the CCCV mode under the conditions of 0.1C-rate and 1% in the 4.25~3.0V section. The charging/discharging curves of the three coin cells are shown in FIG. 9 and Table 10.

CR2032 Coin Cell charging capacity discharge capacity irreversible capacity reversible efficiency Characteristic evaluation result [mAh/g] [mAh/g] [mAh/g] [%] One 391.72 131.07 260.65 33.46 2 391.12 132.33 258.79 33.83 3 386.81 129.59 257.22 33.51 average 389.88 130.99 258.88 33.6

10 is an SEM photograph of commercially available Li ₂ O (left) and an SEM photograph of _{Li 2 O according to the present embodiment.}

It can be seen that the particles according to the embodiment are clearly distinguished as secondary particles.

Tables 11, 12, and 13 below are evaluation data for the results of calcining LNO as described above using the two Li O particles of FIG. 10 .

* It can be seen that the LNO according to the embodiment has improved properties in all aspects.

Particle size analysis result Dmin [um] D50 [um] Dmax [um] comparative goods 4.47 13.23 39.23 development 5.12 17.33 77.33 Incremental (Development-Comparative) 0.65 4.1 0.65 Incremental rate (incremental/comparative) 14.50% 31.00% 97.10%

XRD phase analysis result LNO(%) NiO(%) Li ₂ O(wt%) Sum comparative goods 90.90% 7.60% 1.50% 100% development 94.50% 4.90% 0.60% 100% Incremental (Development-Comparative) 3.60% -2.70% -0.90% 0.00% Incremental rate (incremental/comparative) 3.90% -35.80% -57.00% 0.00%

Residual lithium analysis LiOH [wt%] Li ₂ CO ₃ [wt%] comparative goods 4.19 0.36 development 1.75 0.47 Incremental (Development-Comparative) -2.44 0.11 Incremental rate (incremental/comparative) -58.20% 30.60%

Table 14 below shows the evaluation results after sintering LNO as described above using two Li O of FIG. 10 and manufacturing a coin cell using the same.

It can be seen that the battery data of Examples are significantly improved.

CR2032 Coin Cell charging capacity discharge capacity irreversible capacity reversible efficiency Characteristic evaluation result [mAh/g] [mAh/g] [mAh/g] [%] development 414.4 144.5 269.9 34.90% comparative goods 403.6 139.5 264.1 34.60% Incremental (Development-Comparative) 10.8 5 5.8 0.30% Incremental rate (incremental/comparative) 2.70% 3.60% 2.20% 0.90%

The present invention is not limited to the above embodiments, but can be manufactured in a variety of different forms, and those of ordinary skill in the art to which the present invention pertains can take other specific forms without changing the technical spirit or essential features of the present invention. It will be understood that it can be implemented as Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (11)

_{Li 2} O primary particles having an average particle diameter (D50) of 5 μm or less; and
Lithium compound comprising; secondary particles formed by agglomeration of the primary particles.
According to claim 1,
The secondary particles are spherical lithium compound.
According to claim 1,
The average particle diameter (D50) of the secondary particles is a lithium compound of 10 to 100㎛.
4. The method of claim 3,
The average particle diameter (D50) of the secondary particles is a lithium compound of 10 to 30㎛.
_{A lithium compound comprising Li 2} O primary particles having an average particle diameter (D50) of 5 μm or less and secondary particles formed by agglomeration of the primary particles; and a nickel raw material; a nickel-based positive electrode active material resulting from
The positive electrode active material is a nickel-based positive electrode active material that has a residual lithium compound of 2.5% by weight or less with respect to 100% by weight of the total weight.
6. The method of claim 5,
The positive electrode active material is Li ₂ NiO ₂ Nickel-based positive electrode active material.
reacting hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) to obtain lithium peroxide (Li ₂ O ₂ ); and
Including; heat-treating the perlithium oxide to obtain lithium oxide (Li ₂ O);
reacting the hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) to obtain a lithium peroxide (Li ₂ O ₂ ); in,
The molar ratio of lithium in lithium hydroxide to hydrogen peroxide (Li/H ₂ O ₂ ) is 1.9 to 2.4,
reacting the hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) to obtain a lithium peroxide (Li ₂ O ₂ ); in,
The reaction temperature is 40 to 60 °C,
reacting the hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) to obtain a lithium peroxide (Li ₂ O ₂ ); in,
A method for producing lithium oxide wherein the reaction of hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) is accompanied by stirring at 500 rpm or more.
delete 8. The method of claim 7,
Heating the perlithium oxide to obtain lithium oxide (Li ₂ O);
A method for producing lithium oxide that is carried out at 400 to 600 °C in an inert atmosphere.
reacting hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) to obtain lithium peroxide (Li ₂ O ₂ );
heat-treating perlithium oxide to obtain lithium oxide (Li ₂ O); and
calcining the lithium oxide and nickel raw material to obtain a nickel-based positive electrode active material;
including,
reacting hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) to obtain lithium peroxide (Li ₂ O ₂ ); in,
The molar ratio of lithium in lithium hydroxide to hydrogen peroxide (Li/H ₂ O ₂ ) is 1.9 to 2.4,
reacting the hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) to obtain a lithium peroxide (Li ₂ O ₂ ); in, the reaction temperature is 40 to 60° C.,
reacting the hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) to obtain a lithium peroxide (Li ₂ O ₂ ); in,
The reaction of hydrogen peroxide (H ₂ O ₂ ) and lithium hydroxide (LiOH) is a method for producing a nickel-based positive electrode active material that is accompanied by stirring at 500 rpm or more.
_{A lithium compound comprising Li 2} O primary particles having an average particle diameter (D50) of 5 μm or less and secondary particles formed by agglomeration of the primary particles; and a nickel raw material; a nickel-based positive active material resulting from, wherein the positive active material is a positive electrode including a nickel-based positive active material in which the residual lithium compound is 2.5% by weight or less based on 100% by weight of the total weight;
a negative electrode including an anode active material; and
an electrolyte positioned between the positive electrode and the negative electrode;
A secondary battery comprising a.

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