Precursor for Producing Lithium-rich Cathode Active Material, and Lithium-rich Cathode Active Material Produced Thereby

Abstract

The disclosure relates to a precursor manufacturing a lithium rich cathode active material and a Lithium rich cathode active material using the same, more specifically relates to a novel precursor for manufacturing a lithium rich cathode active material of which capacity properties and cycle life characteristics are considerably improved by solving a problem of conventional lithium rich cathode active material, and a Lithium rich cathode active material using the same.

Claims

1. A precursor for manufacturing lithium rich cathode active material expressed by following chemical formula 2:
Ni.sub.α2Mn.sub.β2-y2CO.sub.γ2-δ2AL.sub.δ2A.sub.y2CO.sub.3  [Chemical formula 2] wherein in the chemical formula 2, A is selected from the group consisting of Mg, Ti and Zr; α2 is 0.05 to 0.4; β2 is 0.5 to 0.8; γ2 is 0 to 0.4; δ1 is 0.001 to 0.1; and y2 is 0.001 to 0.1.

2. The precursor for manufacturing lithium rich cathode active material of claim 1, wherein the particle diameter of the precursor for manufacturing lithium rich cathode active material is 5 to 25 μm.

3. Lithium rich cathode active material expressed by following chemical formula 4, which is manufactured from the precursor for manufacturing lithium rich cathode active material of claim 1:
Li.sub.1+x2Ni.sub.α2Mn.sub.β2-y2CO.sub.γ2-δ2Al.sub.δ2A.sub.y2O.sub.2  [Chemical formula 4] wherein in the chemical formula 4, x2 is 0.2 to 0.7; A is selected from the group consisting of Mg, Ti, and Zr; α2 is 0.05 to 0.4; β2 is 0.5 to 0.8; γ2 is 0 to 0.4; δ2 is 0.001 to 0.1; and y2 is 0.001 to 0.1.

4. The lithium rich cathode active material of claim 3, wherein the lithium rich cathode active material is xLiMAl.sub.δ2O.sub.2.(1-x)Li.sub.2Mn.sub.1-y2A.sub.y2O.sub.3, wherein 0<x<1, M is a compound of Ni, Co, and Mn; A is selected from the group consisting Mg, Ti, and Zr; δ2 is 0.001 to 0.1; and y2 is 0.001 to 0.1.

5. The lithium rich cathode active material of claim 3, wherein the lithium rich cathode active material is a layered structural composite.

6. The lithium rich cathode active material of claim 3, wherein Al content: δ2, Li content: x2 and different metal A content: y2 satisfy following relative formula,
x2δ2 and
y2δ2.

7. The lithium rich cathode active material of claim 3, wherein particle intensity of the lithium rich cathode active material is at least 115 Mpa.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The inventive concepts will become more apparent in view of the attached drawings and accompanying detailed description.

[0034] FIG. 1 shows SEM images of precursor particles for manufacturing lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0035] FIG. 2 shows EDS analyses about sections of precursor particles for manufacturing lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0036] FIG. 3 shows SEM images of precursor particles for manufacturing lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0037] FIG. 4 shows EDS analyses about sections of precursor particles for manufacturing lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0038] FIG. 5 shows a XRD analysis about particles of lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0039] FIG. 6 shows a particle size analysis about particles of lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0040] FIGS. 7 through 9 show SEM images about particles of lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0041] FIGS. 10 through 12 show EDS analyses about particle sections of lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0042] FIGS. 13 through 15 show charging/discharging characteristics of batteries including lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0043] FIG. 16 shows cycle life characteristics of a battery including lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0044] FIG. 17 shows a XRD analysis about particles of lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0045] FIG. 18 shows a particle size analysis about particles of lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0046] FIGS. 19 through 21 show charging/discharging characteristics of batteries including lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0047] FIG. 22 shows cycle life characteristics of a battery including lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0048] FIGS. 23 and 24 show SEM images and EDS analyses of precursor for manufacturing lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0049] FIGS. 25 and 26 show SEM images and EDS analyses of precursor for manufacturing lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0050] FIGS. 27 and 28 show SEM images and EDS analyses of lithium rich cathode active material which is fabricated by an embodiment of the present invention;

[0051] FIGS. 29 and 30 show SEM images and EDS analyses of lithium rich cathode active material which is fabricated by an embodiment of the present invention; and

[0052] FIGS. 31 and 32 shows charging/discharging characteristics of a coin-half cell using lithium rich cathode active material which is fabricated by an embodiment of the present invention.

[0053] FIGS. 33 and 34 show cycle life characteristics of the coin-half cells using the lithium rich cathode active materials which are manufactured by an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] The inventive concepts will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the inventive concepts are shown. The advantages and features of the inventive concepts and methods of achieving them will be apparent from the following exemplary embodiments that will be described in more detail with reference to the accompanying drawings. It should be noted, however, that the inventive concepts are not limited to the following exemplary embodiments, and may be implemented in various forms. Accordingly, the exemplary embodiments are provided only to disclose the inventive concepts and let those skilled in the art know the category of the inventive concepts. In the drawings, embodiments of the inventive concepts are not limited to the specific examples provided herein and are exaggerated for clarity.

[0055] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular terms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it may be directly connected or coupled to the other element or intervening elements may be present.

[0056] Similarly, it will be understood that when an element such as a layer, region or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present. In contrast, the term “directly” means that there are no intervening elements. It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0057] The present inventions will be described below in more detail with reference to exemplary embodiments. However, the inventive concept should not be construed as limited to the embodiments set forth herein.

EXAMPLE 1

Synthesis of a Precursor for Manufacturing Lithium Rich Cathode Active Material

[0058] Nickel sulfate hexahydrate (NiSO.sub.4.6H.sub.2O), cobalt sulfate heptahydrate (CoSO.sub.4.7H.sub.2O), manganese sulfate hydrate (MnSO.sub.4.7H.sub.2O), and metal compound solution containing aluminum sulfate as aluminum compound was poured into a coprecipitation reactor and continuously supplied to perform coprecipitation reaction for 50 hours while 28% ammonia solution as a complexing agent and Na.sub.2CO.sub.3 as a carbonate compound was continuously supplied to adjust pH as 8 to 10, and a slurry solution in the reactor was filtrated and washed by ultrapure distilled water followed by drying in a 110° C. vacuum oven for 12 hours, thereby nickel cobalt aluminum metal complex carbonate compound was obtained. This nickel cobalt aluminum metal complex carbonate compound was Ni.sub.0.2Co.sub.0.07Mn.sub.0.7Al.sub.0.03CO.sub.3.

TABLE-US-00001 TABLE 1 Ni Co Mn Al Example 1-1 20 7 70 3 Example 1-2 20 4 70 6 Comparative Example 1 20 10 70 0 Comparative Example 2 20 2 70 8

[0059] Precursor of the example 1-2 and the comparative examples 1, 2 were synthesized using the same condition except for manufacturing metal compound solution using compound rate in Table 1.

Test Example 1-1

SEM Imaging for Precursor

[0060] SEM images for precursor particles containing Al 3 mol %, which was manufactured in the example 1-1 were taken in accordance with synthesis time, and then the results were shown in FIG. 1. The precursor particles in FIG. 1 were spherical shape of 5 to 25 μm and had dense surfaces.

Test Example 1-2

EDS Analysis for Precursor

[0061] EDS analysis for a section of precursor containing Al 3 mol %, which was manufactured in the example 1-1 were performed in accordance with synthesis time, and then the results were shown in FIG. 2. Saturation amount of Al was maintained at 3 mol % during synthesis time.

Test Example 1-3

SEM Imaging for Precursor

[0062] SEM images for precursor particles containing Al 6 mol %, which was manufactured in the example 1-2 were taken in accordance with synthesis time, and then the results were shown in FIG. 3. The precursor particles in FIG. 1 were spherical shape of 5 to 25 μm and had dense surfaces.

Test Example 1-4

EDS Analysis for Precursor

[0063] EDS analysis for a section of precursor containing Al 6 mol %, which was manufactured in the example 1-2 were performed in accordance with synthesis time, and then the results were shown in FIG. 4. Saturation amount of Al was maintained at 6 mol % during synthesis time.

EXAMPLE 2

Synthesis of Lithium Rich Cathode Active Material Containing Al 3 mol %

[0064] The carbonate precursor containing Al 3 mol% manufactured in the example 1-1 and Li.sub.2CO.sub.3 as a lithium compound were mixed at equivalent ratio, wherein transition metal ratio was in Table 2 followed by thermal treatment at 900° C. and pulverizing, thereby lithium rich cathode active material was synthesized.

TABLE-US-00002 TABLE 2 Li/(NiCoMnAl) Example 2-1 1.40 Example 2-2 1.45 Example 2-3 1.50

Test Example 2-1

XRD Analysis for Active Material

[0065] XRD analysis for particles of lithium rich cathode active material which were manufactured in the examples 2-1 through 2-3 were performed, and then the results were shown in FIG. 5. As shown in FIG. 5, the lithium rich cathode active material had a peak at 2θ=21°.

Test Example 2-2

Particle Size Analysis

[0066] Particle size analysis for particles of lithium rich cathode active material which were manufactured in the examples 2-1 through 2-3 were performed, and then the results were shown in FIG. 6. As shown in FIG. 6, the lithium rich cathode active material manufactured by the example of the present invention had D50 of 17 to 22 μm.

Test Example 2-3

SEM Imaging for Active Material

[0067] SEM images for particles of lithium rich cathode active material which were manufactured in the examples 2-1 through 2-3 were taken, and then the results were shown in FIGS. 7 to 9. As shown in FIGS. 7 to 9, the particles of the lithium rich cathode active material were secondary particles formed by cohered first particles and had spherical shape.

Test Example 2-4

EDS Analysis for Active Material

[0068] EDS analysis for sections of particles of lithium rich cathode active material which were manufactured in the examples 2-1 through 2-3 were performed, and then the results were shown in FIGS. 10 to 12. As shown in FIGS. 10 to 12, the lithium rich cathode active material was coated by Al.

Test Example 2-5

Measuring Charging/Discharging Characteristic

[0069] The lithium rich cathode active material manufactured in the examples 2-1 through example 2-3, carbon black and PVDF[Poly(vinylidene fluoride)] as a binder were mixed with organic solution NMP at weight ratio of 94:3:3 to form a slurry. The slurry was coated on an Al foil of 20 um followed by drying, thereby a cathode was manufactured. A CR2016 coin-half cell was assembled using the cathode, an anode of metal lithium and a membrane of a porous poly ethylene film (CellGard 2502). Solution of 1.1M LiPF.sub.6 EC/EMC/DEC was used for electrolyte.

[0070] FIGS. 13 to 15 show discharging capacity and cycle life characteristic.

EXAMPLE 2-6

Measuring Cycle Life Characteristic

[0071] FIG. 16 shows 50 cycle life characteristic of a battery which was manufactured using the lithium rich cathode active material manufactured by the Examples 2-1 through 2-3. It is shown in FIG. 16 that at least 90% of life was sustained when ratio of Li/M is 1.45 and 1.5.

EXAMPLE 3

Synthesizing Lithium Rich Cathode Active Material Containing Al 6 Mol %

[0072] The carbonate precursor containing Al 6 mol % manufactured in the example 1-2 and Li.sub.2CO.sub.3 as a lithium compound were mixed at equivalent ratio, wherein transition metal ratio was in Table 2 followed by thermal treatment at 900° C. and pulverizing, thereby lithium rich cathode active material was synthesized.

TABLE-US-00003 TABLE 3 Li/(NiCoMnAl) Example 3-1 1.40 Example 3-2 1.45 Example 3-3 1.50

Test Example 3-1

XRD Analysis for Active Material

[0073] XRD analysis for particles of lithium rich cathode active material which was manufactured in the examples 3-1 through 3-3 was performed, and then the results were shown in FIG. 17. As shown in FIG. 17, the lithium rich cathode active material shows a peak at 2θ=21°.

Test Example 3-2

Particle Size Analysis

[0074] Particle size analysis for particles of lithium rich cathode active material which was manufactured in the example 2-1 through 2-3 was performed, and then the results were shown in FIG. 18. As shown in FIG. 18, the lithium rich cathode active material containing Al 6 mol % manufactured by the examples 3-1 through 3-3 of the present invention had D50 of 23 to 25 μm.

Test Example 3-3

Measuring Charging/Discharging Characteristic

[0075] The lithium rich cathode active material manufactured in the examples 3-1 through example 3-3, carbon black and PVDF[Poly(vinylidene fluoride)] as a binder were mixed with organic solution NMP at weight ratio of 94:3:3 to form a slurry. The slurry was coated on an Al foil of 20 μm followed by drying, thereby a cathode was manufactured. A CR2016 coin-half cell was assembled using the cathode, an anode of metal lithium and a membrane of a porous poly ethylene film (CellGard 2502). Solution of 1.1M LiPF.sub.6 EC/EMC/DEC was used for electrolyte.

[0076] FIGS. 19 to 21 show discharging capacity and cycle life characteristic.

Test Example 3-4

Measuring Cycle Life Characteristic

[0077] FIG. 22 shows 50 cycle life characteristic of a battery which was manufactured using the lithium rich cathode active material manufactured by the examples 3-1 through 3-3. It is shown in FIG. 16 that at least 90% of life was sustained when ratio of Li/M is 1.45 and 1.5.

EXAMPLE 4

Synthesizing a Precursor for Manufacturing Lithium Rich Cathode Active Material

[0078] Nickel sulfate hexahydrate (NiSO.sub.4.6H.sub.2O), cobalt sulfate heptahydrate (CoSO.sub.4.7H.sub.2O), manganese sulfate hyemppledrate (MnSO.sub.4.7H.sub.2O), aluminum sulfate as aluminum compound and metal compound solution containing TiO.sub.2 as a different metal was poured into a coprecipitation reactor and continuously supplied to perform coprecipitation reaction for 50 hours while 28% ammonia solution as a complexing agent and Na.sub.2CO.sub.3 as a carbonate compound was continuously supplied to adjust pH as 8 to 10, and then a slurry solution in the reactor was filtrated and washed by ultrapure distilled water followed by drying in a 110° C. vacuum oven for 12 hours, thereby nickel cobalt manganese aluminum titanium metal complex carbonate compound was obtained. This transition metal complex carbonate compound was Ni.sub.0.2Co.sub.0.07Mn.sub.0.67Al.sub.0.03Ti.sub.0.03CO.sub.3.

TABLE-US-00004 TABLE 4 Ni Co Mn Al Ti Zr Mg Example 4-1 20 7 67 3 3 0 0 Example 4-2 20 7 67 3 0 3 3 Example 4-3 20 7 67 3 0 0 1 Example 4-4 20 7 67 3 0 0 2 Comparative Example 4-1 20 10 70 0 0 0 0 Comparative Example 4-2 20 7 70 3 0 0 0 Comparative Example 4-3 20 7 67 0 3 0 0 Comparative Example 4-4 20 7 67 0 0 3 3 Comparative Example 4-5 20 7 64 3 6 0 0 Comparative Example 4-6 20 7 64 3 0 6 6

[0079] Precursor of the examples 4-2 through 4-4 and the comparative examples 4-1 through 4-6 were synthesized using the same condition except for manufacturing metal compound solution using compound rate in Table 4.

Test Example

SEM Imaging and EDS Analysis

[0080] Results of SEM images and EDS analysis of precursor manufactured by the example 4-3 was shown in FIGS. 23 and 24, and results of SEM images and EDS analysis of precursor for manufacturing lithium rich cathode active material which was manufactured at constituent of the example 4-4 was shown in FIGS. 25 and 26.

[0081] The SEM images in FIGS. 23 and 25 shows that Al.sub.2O.sub.3 coated on a surface was cohered, and the result of the EDS measurement shows indicates that doped Al and Mg are coated on particles uniformly.

EXAMPLE 5

Synthesis of Lithium Rich Cathode Active Material

[0082] The carbonate precursor manufactured in the examples 4-1 through 4-4 and the comparative example and Li.sub.2CO.sub.3 as a lithium compound were mixed at equivalent ratio followed by thermal treatment at 900° C. and pulverizing, thereby lithium rich cathode active material was synthesized.

Test Example

SEM Imaging and EDS Analysis

[0083] Results of SEM images and EDS analysis of the example 5-3 which is lithium rich cathode active material manufactured at the precursor constituent of the example 4-3 was shown in FIGS. 27 and 28, and results of SEM images and EDS analysis of the example 5-4 which is lithium rich cathode active material manufactured at the constituent of the example 4-4 was shown in FIGS. 29 and 30.

Test Example

Measuring Battery Properties

[0084] The lithium rich cathode active materials of the examples 5-1 through 5-4 and the examples comparative examples 5-1 through 5-6 manufactured by the example 4-1 through 4-4 and the comparative examples 4-1 through 4-6, carbon black and PVDF[Poly(vinylidene fluoride)] as a binder were mixed with organic solution NMP at weight ratio of 94:3:3 to form a slurry.

[0085] The slurry was coated on an Al foil of 20 μm followed by drying, thereby a cathode was manufactured. A CR2016 coin-half cell was assembled using the cathode, an anode of metal lithium and a membrane of a porous poly ethylene film (CellGard 2502). Solution of 1.1M LiPF.sub.6 EC/EMC/DEC was used for electrolyte.

[0086] Following Table 5 shows discharging capacity and cycle life characteristic.

TABLE-US-00005 TABLE 5 Discharge Room Temperature life Capacity/mAhg-1 after 50 cycles/% Example 5-1 249 95 Example 5-2 250 96 Comparative Example 5-1 261 87 Comparative Example 5-2 259 93 Comparative Example 5-3 254 92 Comparative Example 5-4 253 93 Comparative Example 5-5 240 92 Comparative Example 5-6 239 93

[0087] As shown in Table 5, the lithium rich cathode active material according to examples of the present invention is more improved than the comparative examples in discharging capacity and cycle life characteristic.

[0088] FIGS. 31 and 32 show results of charging/discharging characteristics of CR2016 coin-half cells using the lithium rich cathode active materials at the constituents of the examples 5-3 and 5-4.

Test Example

Measuring Cycle Life Characteristic

[0089] FIGS. 33 and 34 show cycle life characteristics of the CR2016 coin-half cells using the lithium rich cathode active materials of the examples 5-3 and 5-4 which are manufactured at constituents of the examples 4-3 and 4-4.

[0090] As shown in FIGS. 33 and 34, the CR2016 coin-half cells using the lithium rich cathode active materials of the examples 5-3 and 5-4 which are manufactured at constituents of the examples 4-3 and 4-4 maintain capacities until 40 cycles.

Test Example

Measuring Particle Intensity

[0091] Following Table 6 shows particle intensities of the lithium rich cathode active materials of the examples 5-3 and 5-4 which are manufactured at constituents of the comparative examples 4-3 and 4-4, and particle intensities of the lithium rich cathode active materials of the comparative examples 5-3 and 5-4 which are manufactured at constituents of the examples 4-3 and 4-4.

TABLE-US-00006 TABLE 6 ID Particle hardness Comparative Example 5-1 bare 101 Comparative Example 5-2 Al 0.3 111 Example 5-3 Al 0.3 Mg1 116 Example 5-4 Al 0.3 Mg2 116

[0092] According to the present invention, a battery, of which high voltage capacity is improved and cycle life characteristics are improved, can be fabricated by adjusting species and a composition of substituted metal and by adjusting species and an amount of substituting metal, in the precursor for manufacturing lithium rich cathode active material and the lithium rich cathode active material using the same.

[0093] According to the precursor for manufacturing lithium rich cathode active material and the lithium rich cathode active material using the same, species and content of substituted metal from the precursor are adjust and species and addition amount of substituting metal are adjust to manufacture a battery of which high voltage properties and cycle life characteristics are improved.