Method for synthesizing spinel coated single crystal cathode active material

Abstract

The invention relates to a method for synthesizing a spinel coated single crystal cathode active material. A method of making a cathode active material includes providing a polycrystalline transition metal precursor; providing a lithium salt composition comprising a first lithium salt and a second lithium salt having a eutectic melting temperature; producing a first mixture comprising the polycrystalline transition metal precursor and the lithium salt composition; mixing the first mixture in a mixer to generate mutual friction, thereby heating the lithium salt composition above the eutectic melting temperature and generating a second mixture; and sintering the second mixture to form the spinel coated single crystal cathode active material.

Description

Technical Field

[0001] The present disclosure relates to battery cells for battery packs, and more particularly to a method of synthesizing a spinel-coated single-crystalline cathode active material for a cathode electrode. Background Art

[0002] The information provided in this section is for the purpose of generally presenting the background of the present disclosure. To the extent that the work of the presently named inventors is described in this section, and to the extent that the specification may originally not have been eligible as prior art at the time of filing, it is not expressly or impliedly admitted as prior art to the present disclosure.

[0003] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles include one or more electric motors and a battery pack system that includes one or more battery cells, modules, and / or packs. A power control system is used to control charging and / or discharging of the battery pack system during charging and / or driving.

[0004] A battery cell includes a cathode electrode, an anode electrode, and a separator. The cathode electrode includes a cathode active material layer disposed on a cathode current collector. The anode electrode includes an anode active material layer disposed on an anode current collector. Summary of the Invention

[0005] A method of manufacturing a cathode active material includes providing a polycrystalline transition metal precursor; providing a lithium salt composition that includes a first lithium salt and a second lithium salt having a eutectic melting temperature; manufacturing a first mixture that includes the polycrystalline transition metal precursor and the lithium salt composition; mixing the first mixture in a mixer to generate mutual frictional forces, thereby heating the lithium salt composition to a temperature above the eutectic melting temperature and generating a second mixture; and sintering the second mixture to form a spinel-coated single-crystalline cathode active material.

[0006] In other features, the polycrystalline transition metal precursor and the lithium salt composition are mixed in a mixer selected from a planetary centrifugal mixer, a ball mill, a theta composer, and an acoustic mixer for a predetermined time of 5 to 120 minutes. Providing the polycrystalline transition metal precursor includes manufacturing a third mixture that includes one or more transition metal precursors and one or more precursors of one of hydroxides, carbonates, oxalates, and oxides; and heating and stirring the third mixture for a predetermined time.

[0007] Among other features, the third mixture is heated to a predetermined temperature of 25°C to 80°C. The third mixture is stirred at a predetermined speed of 700 to 2000 rpm. The predetermined time is from 0.5 hour to 48 hours. The pH of the polycrystalline transition metal precursor is 7.5 to 11.5. The polycrystalline transition metal precursor includes one or more transition metals selected from nickel (Ni), manganese (Mn), iron (Fe), molybdenum (Mo), niobium (Nb), magnesium (Mg), aluminum (Al), titanium (Ti), zirconium (Zr), copper (Cu), and cobalt (Co).

[0008] Among other features, the eutectic melting temperature is less than or equal to 200°C. The molar ratio of the lithium salt composition to the polycrystalline transition metal precursor is 1.1 to 1.6.

[0009] Among other features, the one or more transition metal precursors include aqueous manganese sulfate and aqueous nickel sulfate. The one or more precursors include sodium hydroxide and ammonium hydroxide. The first lithium salt includes lithium hydroxide. The second lithium salt includes lithium nitrate.

[0010] Among other features, the spinel-coated single-crystal cathode active material includes lithium-and manganese-rich (LMR), lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium nickel manganese cobalt (NMC), lithium nickel manganese cobalt aluminum (NMCA), lithium nickel cobalt aluminum (NCA), lithium iron phosphate (LFP), and lithium manganese iron phosphate (LMFP).

[0011] A method of manufacturing a cathode active material includes manufacturing a polycrystalline transition metal precursor as follows: manufacturing a first mixture including one or more transition metal precursors selected from one or more transition metals selected from nickel (Ni), manganese (Mn), iron (Fe), molybdenum (Mo), niobium (Nb), magnesium (Mg), aluminum (Al), titanium (Ti), zirconium (Zr), copper (Cu), and cobalt (Co) and one or more precursors of one of hydroxides, carbonates, oxalates, and oxides; and heating and stirring the first mixture for a predetermined time. The method includes providing a lithium salt composition including a first lithium salt and a second lithium salt having an eutectic melting temperature below 200°C; combining the polycrystalline transition metal precursor and the lithium salt composition to manufacture a second mixture; using a mixer to mix the second mixture to generate mutual frictional force and heating the lithium salt composition to a temperature higher than the eutectic melting temperature to form a third mixture; and sintering the third mixture to form a spinel-coated single-crystal cathode active material selected from lithium-and manganese-rich LMR, lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium nickel manganese cobalt (NMC), lithium nickel manganese cobalt aluminum (NMCA), lithium nickel cobalt aluminum (NCA), lithium iron phosphate (LFP), and lithium manganese iron phosphate (LMFP).

[0012] Among other features, the polycrystalline transition metal precursor and the lithium salt composition are mixed for a predetermined time of 5 to 120 minutes in a mixer selected from a planetary centrifugal mixer, a ball mill, a theta composer, and an acoustic mixer. The first mixture is heated to a predetermined temperature of 25°C to 80°C. The first mixture is stirred at a predetermined speed of 700 to 2000 rpm. The predetermined time is 0.5 hour to 48 hours.

[0013] Among other features, the pH of the polycrystalline transition metal precursor is 7.5 to 11.5. The molar ratio of the lithium salt composition to the polycrystalline transition metal precursor is 1.1 to 1.6. The one or more transition metal precursors include aqueous manganese sulfate and aqueous nickel sulfate. The one or more precursors include sodium hydroxide and ammonium hydroxide. The first lithium salt includes lithium hydroxide and the second lithium salt includes lithium nitrate.

[0014] The present invention discloses the following solutions:

[0015] Solution 1. A method for manufacturing a cathode active material, comprising:

[0016] providing a polycrystalline transition metal precursor;

[0017] providing a lithium salt composition comprising a first lithium salt and a second lithium salt having a eutectic melting temperature;

[0018] manufacturing a first mixture comprising the polycrystalline transition metal precursor and the lithium salt composition;

[0019] mixing the first mixture in a mixer to generate mutual frictional force, thereby heating the lithium salt composition to a temperature higher than the eutectic melting temperature and generating a second mixture; and

[0020] sintering the second mixture to form a spinel-coated single-crystal cathode active material.

[0021] Solution 2. The method according to Solution 1, wherein the polycrystalline transition metal precursor and the lithium salt composition are mixed for a predetermined time of 5 to 120 minutes in a mixer selected from a planetary centrifugal mixer, a ball mill, a theta composer, and an acoustic mixer.

[0022] Solution 3. The method according to Solution 1, wherein providing the polycrystalline transition metal precursor comprises:

[0023] manufacturing a third mixture comprising one or more transition metal precursors and one or more precursors of one of hydroxides, carbonates, oxalates, and oxides; and

[0024] heating and stirring the third mixture for a predetermined time.

[0025] Embodiment 4. The method according to Embodiment 3, wherein the third mixture is heated to a predetermined temperature of 25°C to 80°C.

[0026] Embodiment 5. The method according to Embodiment 3, wherein the third mixture is stirred at a predetermined speed of 700 to 2000 rpm.

[0027] Embodiment 6. The method according to Embodiment 3, wherein the predetermined time is 0.5 hour to 48 hours.

[0028] Embodiment 7. The method according to Embodiment 1, wherein the pH of the polycrystalline transition metal precursor is 7.5 to 11.5.

[0029] Embodiment 8. The method according to Embodiment 1, wherein the polycrystalline transition metal precursor comprises one or more transition metals selected from nickel (Ni), manganese (Mn), iron (Fe), molybdenum (Mo), niobium (Nb), magnesium (Mg), aluminum (Al), titanium (Ti), zirconium (Zr), copper (Cu), and cobalt (Co).

[0030] Embodiment 9. The method according to Embodiment 1, wherein the eutectic melting temperature is less than or equal to 200°C.

[0031] Embodiment 10. The method according to Embodiment 1, wherein the molar ratio of the lithium salt composition to the polycrystalline transition metal precursor is 1.1 to 1.6.

[0032] Embodiment 11. The method according to Embodiment 3, wherein:

[0033] the one or more transition metal precursors comprise aqueous manganese sulfate and aqueous nickel sulfate,

[0034] the one or more precursors comprise sodium hydroxide and ammonium hydroxide,

[0035] the first lithium salt comprises lithium hydroxide, and

[0036] the second lithium salt comprises lithium nitrate.

[0037] Embodiment 12. The method according to Embodiment 1, wherein the spinel-coated single-crystal cathode active material comprises a lithium-and manganese-rich (LMR) material, lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium nickel manganese cobalt (NMC), lithium nickel manganese cobalt aluminum (NMCA), lithium nickel cobalt aluminum (NCA), lithium iron phosphate (LFP), and lithium manganese iron phosphate (LMFP).

[0038] Embodiment 13. A method of manufacturing a cathode active material, comprising:

[0039] Manufacture a polycrystalline transition metal precursor as follows:

[0040] Prepare a first mixture including one or more transition metal precursors selected from one or more transition metals of nickel (Ni), manganese (Mn), iron (Fe), molybdenum (Mo), niobium (Nb), magnesium (Mg), aluminum (Al), titanium (Ti), zirconium (Zr), copper (Cu), and cobalt (Co), and one or more precursors selected from hydroxides, carbonates, oxalates, and oxides; and

[0041] Heat and stir the first mixture for a predetermined time;

[0042] Provide a lithium salt composition including a first lithium salt and a second lithium salt having a eutectic melting temperature below 200 °C;

[0043] Combine the polycrystalline transition metal precursor and the lithium salt composition to prepare a second mixture;

[0044] Use a mixer to mix the second mixture to generate mutual frictional force and heat the lithium salt composition to a temperature higher than the eutectic melting temperature to form a third mixture; and

[0045] Sinter the third mixture to form a spinel-coated single-crystalline cathode active material selected from lithium-rich manganese materials LMR, lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium nickel manganese cobalt (NMC), lithium nickel manganese cobalt aluminum (NMCA), lithium nickel cobalt aluminum (NCA), lithium iron phosphate (LFP), and lithium manganese iron phosphate (LMFP).

[0046] Scheme 14. The method according to Scheme 13, wherein the polycrystalline transition metal precursor and the lithium salt composition are mixed in a mixer selected from a planetary centrifugal mixer, a ball mill, a theta composer, and an acoustic mixer for a predetermined time of 5 to 120 minutes.

[0047] Scheme 15. The method according to Scheme 13, wherein:

[0048] Heat the first mixture to a predetermined temperature between 25 °C and 80 °C,

[0049] Stir the first mixture at a predetermined speed of 700 to 2000 rpm, and

[0050] The predetermined time is 0.5 hour to 48 hours.

[0051] Scheme 16. The method according to Scheme 13, wherein the pH of the polycrystalline transition metal precursor is 7.5 to 11.5.

[0052] Embodiment 17. The method according to Embodiment 13, wherein the molar ratio of the lithium salt composition to the polycrystalline transition metal precursor is from 1.1 to 1.6.

[0053] Embodiment 18. The method according to Embodiment 13, wherein:

[0054] the one or more transition metal precursors comprise aqueous manganese sulfate and aqueous nickel sulfate,

[0055] the one or more precursors comprise sodium hydroxide and ammonium hydroxide, and

[0056] the first lithium salt comprises lithium hydroxide and the second lithium salt comprises lithium nitrate.

[0057] Further applicable fields of the present disclosure will be apparent from the detailed description, the claims, and the drawings. The detailed description and the specific examples are only intended to illustrate and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The present disclosure is more fully understood from the detailed description and the drawings, in which:

[0059] Figure 1 is a side cross-section of an example of a battery cell of a battery pack including an anode electrode, a cathode electrode, and a separator according to the present disclosure;

[0060] Figure 2 is a side cross-section of an example of a cathode electrode according to the present disclosure; and

[0061] Figure 3A illustrates an example of a polycrystalline transition metal precursor mixed with a lithium salt composition according to the present disclosure and grain boundary destruction caused by melting of the lithium salt composition due to interparticle friction generated during mixing;

[0062] Figure 3B illustrates an example of a planetary mixer for mixing a polycrystalline transition metal precursor and a lithium salt composition according to the present disclosure;

[0063] Figure 4 and 5 is a flow chart of an example of a method for synthesizing a spinel-coated single crystal cathode active material according to the present disclosure;

[0064] Figure 6 is a scanning electron microscope image of an example of a spinel-coated single crystal cathode active material according to the present disclosure;

[0065] Figure 7 is a graph of x-ray diffraction (XRD) illustrating an example of a spinel-coated single crystal cathode active material according to the present disclosure;

[0066] Figure 8is a graph comparing the specific capacity and Coulombic efficiency of a cathode electrode including an LMR made in accordance with the present disclosure with an exemplary commercially available LMR; and

[0067] Figure 9 is a graph of dQ / dV vs. voltage confirming the spinel phase during the first formation cycle.

[0068] In the drawings, reference numerals may be reused to designate similar and / or identical elements. Detailed Description

[0069] Although the battery pack cells according to the present disclosure are shown in the context of an electric vehicle, the battery pack cells can be used in stationary applications and / or other applications.

[0070] Existing methods for synthesizing single crystal cathode active materials (e.g., lithium-rich manganese (LMR) cathode active materials) include high temperature sintering or molten salt synthesis. High temperature sintering typically requires temperatures above 1000 °C and an excess of lithium content to offset lithium evaporation. The high temperature sintering method may also require a post-calcination washing step. Molten salt synthesis requires a large amount of molten salt. The cathode active material may also require washing after high temperature calcination.

[0071] The present disclosure relates to a method for preparing a cathode active material (e.g., a spinel-coated single crystal LMR cathode active material) stabilized by a spinel phase formed during the preparation process. In some instances, the spinel phase is formed by controlling the ratio of transition metals, such as the Ni / Mn or Li to total transition metal ratio. In some instances, the transition metals are selected from nickel (Ni), manganese (Mn), iron (Fe), molybdenum (Mo), niobium (Nb), magnesium (Mg), aluminum (Al), titanium (Ti), zirconium (Zr), copper (Cu), and cobalt (Co). In some instances, the method can be carried out at temperatures below 900 °C. No molten salt is required and significantly less excess lithium salt is needed, which reduces the manufacturing cost.

[0072] The preparation method is based on interfacial reactive wetting, which is mediated by a transient eutectic salt melted in situ by moderate mechanical mixing to form a colloidal suspension of LMR precursors dispersed in a liquefied lithium salt. The preparation method effectively depolymerizes the polycrystalline precursors and homogenizes the lithium salt distribution. This allows the particles to subsequently be easily coarsened into a single crystal morphology with improved electrochemical performance.

[0073] Now refer to Figure 1, the battery pack cell 10 includes C cathode electrodes 20, A anode electrodes 40, and S separators 32 arranged in a battery pack cell stack 12 in a predetermined order, where C, S, and A are integers greater than 0. The battery pack cell stack 12 is arranged in a housing 50. The C cathode electrodes 20-1, 20-2, ..., and 20-C include cathode active material layers 24 arranged on one or both sides of a cathode current collector 26.

[0074] The A anode electrodes 40-1, 40-2, ..., and 40-A include anode active material layers 42 arranged on one or both sides of an anode current collector 46. The S separators 32-1, 32-2, ..., and 32-S are arranged between adjacent pairs of the C cathode electrodes 20 and the A anode electrodes 40. In some examples, the cathode active material layer 24 and / or the anode active material layer 42 includes a coating that is cast or applied to the current collector and includes one or more active materials, one or more conductive additives, and / or one or more binder materials. During charge / discharge, the A anode electrodes 40 and the C cathode electrodes 20 exchange lithium ions.

[0075] In some examples, the cathode current collector 26 and / or the anode current collector 46 includes a metal foil, a metal mesh, a perforated metal plate, a three-dimensional (3D) metal foam, and / or an expanded metal. In some examples, the current collector is made of one or more materials selected from copper, stainless steel, brass, bronze, zinc, aluminum, and / or their alloys. The external tabs 28 and 48 are respectively connected to the current collectors of the cathode electrode and the anode electrode, and can be arranged on the same side or different sides of the battery pack cell stack 12. The external tabs 28 and 48 are connected to the terminals of the battery pack.

[0076] Now referring to Figure 2 , the C cathode electrodes 20 are shown in more detail. The cathode active material layer 24 of the C cathode electrodes 20 includes a cathode active material 62, an optional conductive additive 64, and an optional binder 66. In some examples, the cathode active material includes a lithium-and manganese-rich (LMR) material, a lithium manganese oxide (LMO), a lithium nickel manganese oxide (LNMO), a lithium nickel manganese cobalt (NMC), a lithium nickel manganese cobalt aluminum (NMCA), a lithium nickel cobalt aluminum (NCA), a lithium iron phosphate (LFP), and a lithium manganese iron phosphate (LMFP).

[0077] Now referring to Figure 3A and 3B , before mixing in a planetary or other type of mixer, (one or more) polycrystalline transition metal precursors 80 are coated with lithium salts 82 and 84. In Figure 3ADuring this process, inter-particle friction is generated during mixing to melt the lithium salt. The molten lithium salt wets, corrodes, and separates the grain boundaries 86 of the (one or more) polycrystalline transition metal precursors 80. In Figure 3B planetary mixing or other types of mixing of the (one or more) polycrystalline transition metal precursors and the lithium salt can be used. When planetary mixing is used, the mixing vessel rotates with planetary motion.

[0078] Now refer to Figure 4 which shows a method for preparing a cathode active material. At 110, a mixture of one or more precursors and / or hydroxides, carbonates, oxalates, and / or oxide precursors of one or more transition metals is fabricated. In some instances, the transition metals are selected from nickel (Ni), manganese (Mn), iron (Fe), molybdenum (Mo), niobium (Nb), magnesium (Mg), aluminum (Al), titanium (Ti), zirconium (Zr), copper (Cu), and cobalt (Co). For example, for LMR, the mixture can include aqueous manganese sulfate (MnSO4), aqueous nickel sulfate (NiSO4), sodium hydroxide (NaOH), and ammonium hydroxide (NH4OH).

[0079] At 114, the mixture is heated and stirred for a predetermined reaction time at a predetermined temperature and mixing speed to precipitate or co-precipitate the transition metals and form a polycrystalline transition metal precursor (e.g., Mn 0.7 Ni 0.3 (OH)2). In some instances, the predetermined temperature is from 25 °C to 80 °C. In some instances, the pH of the mixture is controlled at 7.5 to 11.5 to control the morphology.

[0080] In some instances, the mixture is stirred at a speed of 700 to 2000 rpm. In some instances, the predetermined reaction time is from 0.5 hour to 48 hours. Precipitation or co-precipitation occurs to form a polycrystalline transition metal precursor.

[0081] At 118, a lithium salt composition including two or more lithium salts is added to the polycrystalline transition metal precursor. The composition of the two or more lithium salts is close to the corresponding eutectic point. In some instances, the eutectic melting temperature is below 200 °C. In some instances, the lithium salts are selected from lithium carbonate (Li2CO3), lithium nitrate (LiNO3), lithium hydroxide (LiOH), lithium chloride (LiCl), lithium fluoride (LiF), and / or combinations thereof (e.g., the eutectic melting temperature is below 200 °C).

[0082] In some instances, the molar ratio of the lithium salt to the transition metal is 1.1 to 1.6. In some instances, for LMR, the ratio of Mn to Ni is 1.0 to 4.0.

[0083] At 122, the mixture is mixed for a predetermined time. In some examples, the mixer includes a planetary centrifugal mixer, a ball mill, a theta composer, or an acoustic mixer. In some examples, the predetermined time is from 5 minutes to 120 minutes. This mixing increases the interparticle friction to raise the temperature of the mixture above the eutectic melting temperature. The lithium salt composition melts to wet, corrode, and separate the grain boundaries of the polycrystalline transition metal precursor.

[0084] At 124, the mixture is sintered after mixing to form a spinel-coated single-crystalline cathode active material. In some examples, the mixture is heated in air or oxygen to a temperature of 500 °C to 1200 °C for a predetermined time of 1 hour to 48 hours. In some examples, the single-crystalline grain size of the spinel-coated single-crystalline cathode active material is from 0.5 μm to 2 μm. In some examples, the spinel phase is from 1 wt% to 10 wt%. The spinel phase stabilizes the cathode active material.

[0085] Now refer to Figure 5 , which shows a method for preparing a spinel-coated single-crystalline LMR cathode active material. At 210, a mixture is made and includes Mn, Ni, and a hydroxide precursor. For example, for LMR, the mixture can include aqueous manganese sulfate (MnSO4), aqueous nickel sulfate (NiSO4), sodium hydroxide (NaOH), and ammonium hydroxide (NH4OH). At 214, the mixture is heated and stirred at a predetermined temperature and mixing speed for a predetermined reaction time to precipitate or co-precipitate the transition metals and form Mn 0.7 Ni 0.3 (OH)2.

[0086] At 218, a lithium salt composition including LiOH and LiNO3 near the corresponding eutectic point is added to the polycrystalline transition metal precursor. At 222, the mixture is mixed in a mixer for a predetermined time. The lithium salt composition melts to wet, corrode, and separate the grain boundaries of the polycrystalline transition metal precursor. At 224, the mixture is sintered after mixing to form a spinel-coated single-crystalline LMR cathode active material.

[0087] Now refer to Figures 6 to 9 , and several different methods are used to confirm the composition of the spinel-coated single-crystalline cathode active material (such as LMR) made using the method described herein. In Figure 6 , a scanning electron microscope image of the spinel-coated single-crystalline cathode active material is shown. In Figure 7 , an x-ray diffraction (XRD) of an example of the spinel-coated single-crystalline cathode active material is shown. The peaks in the XRD correspond to the desired materials in the cathode active material. In Figure 8Among them, the specific capacity and Coulomb efficiency of the cathode electrode including the LMR made according to the present disclosure at 214 are compared with an example of a commercially available LMR cathode active material at 210. The LMR particles have similar properties. In Figure 9 Among them, a graph of dQ / dV vs. voltage during the first formation cycle is shown. The local minimum at 2.7V proves the formation of the spinel phase. In this example, the first cycle efficiency is 74.72% (vs. 78.11 for commercially available LMR), the first cycle discharge capacity at C / 20 is 223.04 mAh / g (vs. 224.91 mAh / g), and the first cycle discharge capacity at C / 3 is 193.34 mAh / g (vs. 197.57 mAh / g). Therefore, the LMR made using the method described herein has similar properties at a much lower cost.

[0088] The foregoing description is merely exemplary and is in no way intended to limit the present disclosure, its application, or uses. The broad teachings of the present disclosure may be implemented in a variety of forms. Thus, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited since other modifications will become apparent after study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be implemented in a different order (or concurrently) without altering the principles of the present disclosure. Additionally, although the various embodiments have been described above as having certain features, any one or more of the features described with respect to any one embodiment of the present disclosure may be implemented in and / or combined with the features of any other embodiment, even if not explicitly described in combination. In other words, the described embodiments are not mutually exclusive, and permutations of one or more of the embodiments are still within the scope of the present disclosure.

[0089] Spatial and functional relationships between elements (such as between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected", "joined", "coupled", "adjacent", "next to", "on top of", "on", "under", and "disposed". Unless explicitly described as "direct", when the relationship between a first element and a second element is described in the foregoing disclosure, the relationship may be a direct relationship in which no other intermediate element exists between the first element and the second element, or an indirect relationship in which one or more intermediate elements exist between the first element and the second element (spatially or functionally). The phrase "at least one of A, B, and C" as used herein should be construed to mean a logical (A or B or C) using a non-exclusive logical OR and should not be construed to mean "at least one A, at least one B, and at least one C".

[0090] In the drawings, the direction of the arrow as indicated by the arrowhead generally demonstrates the flow of information (such as data or instructions) related to the illustration. For example, when component A and component B exchange various information but the information transmitted from component A to component B is related to the illustration, the arrow can point from component A to component B. Such a one-way arrow does not mean that there is no other information transmitted from component B to component A. In addition, for the information transmitted from component A to component B, component B can send a request for that information or receive an acknowledgment from component A.

Claims

1. A method for producing a cathode active material, comprising: providing a polycrystalline transition metal precursor; providing a lithium salt composition including a first lithium salt and a second lithium salt having a eutectic melting temperature; producing a first mixture comprising the polycrystalline transition metal precursor and the lithium salt composition; mixing the first mixture in a mixer to generate mutual friction forces, thereby heating the lithium salt composition to above the eutectic melting temperature and generating a second mixture; and The second mixture is sintered to form a spinel coated single crystal cathode active material.

2. The method of claim 1, wherein the polycrystalline transition metal precursor and the lithium salt composition are mixed in a mixer selected from a planetary centrifugal mixer, a ball mill, a theta composer, and an acoustic mixer for a predetermined time of 5 to 120 minutes.

3. The method of claim 1 , wherein providing the polycrystalline transition metal precursor comprises: producing a third mixture comprising one or more transition metal precursors and one or more precursors of one of a hydroxide, a carbonate, an oxalate, and an oxide; and The third mixture is heated and stirred for a predetermined time. The method according to claim 3 , wherein the third mixture is heated to a predetermined temperature of 25° C. to 80° C. The method according to claim 3 , wherein the third mixture is stirred at a predetermined speed of 700 to 2000 rpm. The method according to claim 3 , wherein the predetermined time is 0.5 hour to 48 hours.

7. The method of claim 1, wherein the pH of the polycrystalline transition metal precursor is 7.5 to 11.

5.

8. The method of claim 1, wherein the polycrystalline transition metal precursor comprises one or more transition metals selected from nickel (Ni), manganese (Mn), iron (Fe), molybdenum (Mo), niobium (Nb), magnesium (Mg), aluminum (Al), titanium (Ti), zirconium (Zr), copper (Cu) and cobalt (Co).

9. The method of claim 1, wherein the eutectic melting temperature is less than or equal to 200°C.

10. The method of claim 1, wherein a molar ratio of the lithium salt composition to the polycrystalline transition metal precursor is from 1.1 to 1.6.

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