Method for manufacturing cathode material for rechargeable lithium battery

Abstract

To provide a method for manufacturing a high capacity positive electrode material for use in a rechargeable lithium battery.SOLUTION: A method uses mixed metals as feedstocks for wet chemical reactions to create high quality precursors that can be used to prepare high quality cathode materials after lithiation. An important feature is that in the precursor preparation method, most of the aqueous solutions used in the wet chemical reactions are recycled back to the reactor, such that the overall method produces little or no emissions during the production of the cathode precursor material.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of priority to U.S. Provisional Application No. 62 / 899,677, filed on September 12, 2019, the entire disclosure of which is incorporated herein by reference for all purposes.

[0002] The present invention relates to a method for manufacturing a cathode material for a rechargeable lithium (Li) battery and to a cathode material manufactured by such method. In particular, the provided method relates to the relatively emission - free manufacture of such cathode materials when compared to current industrial methods.

Background Art

[0003] (Description of the Prior Art) Rechargeable Li - ion batteries have been used in several different types of devices as energy storage elements. These devices include mobile phones, portable computers, cordless power tools, and hybrid and pure electric vehicles. In recent years, with the rapid market growth of electric vehicles in particular, the demand for high - power Li - ion batteries has increased exponentially. The main components of a lithium - ion battery include an anode, a cathode, and an electrolyte. During charge - discharge cycles, lithium ions move back and forth between the anode active material and the cathode active material through the electrolyte. Since its specific capacity is limited and the manufacturing cost and raw material cost are high, the cathode active material is usually the most expensive element in a Li - ion battery. Therefore, the selection of the cathode active material is an important step for improving the performance of Li - ion batteries and reducing costs.

[0004] Currently, lithium mixed metal oxides, which mostly contain nickel, cobalt, manganese, and / or aluminum along with other necessary dopants, are the main components used in the manufacture of high - performance cathode active materials. The demand and production of such materials have been continuously increasing significantly.

[0005] Current industrial methods for manufacturing these high-performance cathode materials, such as lithium mixed metal oxides, involve two main steps. The first step is the precursor manufacturing step, and the second step is the lithiation step. The precursor step begins with the use of mixed metal sulfates dissolved in water to form an aqueous solution. However, these methods can release undesirable emissions. SUMMARY OF THE INVENTION

[0006] The advantages set forth above, as well as other objects and goals specific thereto, are at least partially or fully provided by the method of the present invention, as shown hereinafter in this specification.

[0007] One embodiment of the present invention is a method for manufacturing a cathode material for a battery, such as a lithium-ion battery, which method reduces the amount of toxic or hazardous emissions from currently known methods for making lithium mixed metal oxides. Accordingly, it would be desirable to provide a suitable method with little or no emissions generation. In one embodiment, the method provides a system in which essentially the entire liquid portion from the reaction is completely recyclable or can be recycled into the reaction system without significant processing. Moreover, the method may require little or no need to evaporate water and / or decompose organic or nitrate substances during the final high-temperature treatment / firing method.

[0008] One embodiment is a method for manufacturing a cathode active material. The method comprises: providing an aqueous solution having a pH greater than 7; adding a first metal to the aqueous solution to form a reaction solution, wherein the first metal is selected from the group consisting of nickel, manganese, cobalt, aluminum, magnesium, and combinations thereof; Forming a product solution including the step of adding an oxidizing agent and a second metal to a reaction solution, wherein the second metal is selected from at least two elements from the group consisting of nickel, manganese, cobalt, aluminum, magnesium, zirconium, yttrium, titanium, vanadium, molybdenum, and combinations thereof, the product solution includes a cathode active material precursor, and the cathode active material precursor product includes a first metal and a second metal, wherein the first metal and the second metal are not the same, forming the product solution; Isolating at least a portion of the cathode active material precursor from the product solution, thereby forming a filtrate.

[0009] Another embodiment provides a chemical method for manufacturing a lithium mixed metal oxide as a cathode active material for use in a rechargeable lithium battery. This method includes two main steps, namely a wet chemical method for fabricating a precursor and a solid state reaction called "lithiation" for fabricating the final cathode material.

[0010] One embodiment of the present invention provides a method for manufacturing a lithium mixed metal oxide as a cathode active material for use in the manufacture of a lithium ion battery using two main steps, namely a precursor preparation step and a lithiation step. Here,

[0011] (A) In the precursor preparation step, the selected metals in their metal forms are added together with one selected oxidizing agent or a plurality of oxidizing agents, a selected metal nitrate, and nitic acid to a stirred reaction system containing a mixture of solid metal particles and mixed metal hydroxide particles in an aqueous solution, and these are also introduced into a reactor to cause oxidation of the metal particles under alkaline conditions. Here, the overall oxidation reaction is represented by the following formula. xMe + yMe´(NO3) n + zHNO3 + (0.25xm - 2yn - 2z)O2 + (0.5xm + 2yn + z)H2O → Me x Me´ y (OH) (xm+yn) +(yn + z)NH3 In the formula, Me represents at least one metal in a metallic form selected from the group consisting of nickel, manganese, cobalt, aluminum, and magnesium; Me´ represents at least one metal in an ionic form thereof selected from the group consisting of nickel, manganese, cobalt, aluminum, magnesium, zirconium, yttrium, titanium, vanadium, and molybdenum; Me x Me´ y (OH) (xm+yn) represents a precursor product; x and y are the molar fractions of metals Me and Me´, respectively, m is the molar weighted average valence of the mixed metal Me in the precursor product, n is the molar weighted average valence of the mixed metal Me´ in ionic form in the reactants, and z is the molar fraction of HNO3 introduced into the reaction system; xm≧8yn + 8z, x + y = 1, 1≧x>0, y≧0, z≧0. Here, the slurry obtained from the oxidation reaction is taken out from the reactor, the unreacted raw material metal is removed from the slurry, and is reused into the reaction system regardless of the presence or absence of a reactivation treatment using nitric acid and / or a combination of nitric acid and ammonia / ammonium. Then, solid-liquid separation is performed. Here, the recovered solid substance is used as the precursor product, and the liquid substance is directly reused into the reaction system without any treatment. And,

[0012] (B) In the lithiation step, the recovered precursor product is mixed with a lithium-containing compound and optionally other dopants to produce a final mixture, and then the final mixture is fired to obtain a cathode active material.

[0013] In one embodiment, a raw material that can be mostly in a metallic form is introduced into the reaction system. The reaction The reaction system typically comprises at least one stirred mixing tank and a reactor, and the reactor may be provided with a magnetic separation device for removing and recycling unreacted raw materials. A reactivation step may be provided before recycling the unreacted raw materials to keep the raw materials in an active state during the reaction. An oxidizing agent such as oxygen and / or nitrate is introduced into the reaction system to cause oxidation of the metal. After the reaction, a solid-liquid separation operation is performed. The liquid part may be recycled to the reaction system, and the solid part is recovered as a precursor substance. An artificial solution having essentially the same or a similar composition as the filtrate may be prepared and used at the start of the reaction until a suitable filtrate is produced from the filtration system and then recycled to the reaction system.

[0014] In the lithiation stage, the precursor substance produced above is mixed with a lithium-containing compound and optionally other dopants, then a firing treatment is carried out, and subsequently additional surface treatment is carried out as necessary, whereby the final cathode active material is obtained.

[0015] Accordingly, embodiments of the present invention provide a system and method for making lithium mixed metal oxides with little or no generation of emissions. That is, this system can enable the entire essentially liquid part from the reaction to be completely recycled to the reaction system without any treatment.

[0016] As an additional feature, the method of the present invention can be carried out in a batch process, but can also be carried out in an essentially continuous process as described below.

[0017] In another embodiment, the present invention also provides a cathode material precursor product, wherein suitable cathode material precursors are produced, and these precursors are produced in a stable continuous manner in a one-step reaction system in the manner described herein. This embodiment also includes the final cathode active material when produced by the method described herein with respect to the present invention, and cathodes produced therefrom.

[0018] In a third aspect, the present invention also provides a battery, where the positive electrode of the battery is manufactured by the chemical method described above with respect to the embodiments of the present invention.

Brief Description of the Drawings

[0019] Here, the following non-limiting examples are used and the accompanying drawings are referred to in order to demonstrate the embodiments.

[0020]

Figure 1

[0021]

Figure 2

[0022]

Figure 3

[0023] However, it should be clearly understood that the examples and drawings are for illustrative purposes only and do not necessarily limit the scope of the present invention.

Modes for Carrying Out the Invention

[0024] Embodiments relate to a method for the manufacture of a cathode material for an energy storage device, particularly a lithium-ion battery, where the method typically improves and / or solves the problem of emissions associated with the fabrication of lithium metal oxides. Thus, the described method produces little or no emissions, and essentially the entire liquid portion from the reaction may be completely recycled back into the reaction system without any significant treatment. Such a system is further advantageous because it requires little or no need to evaporate water and / or decompose organic matter or nitrates during the final high-temperature treatment / firing process.

[0025] It is well known that metal oxides or metal hydroxides can be formed from corrosion methods, for example, metal oxidation in an aqueous solution or in a hydrated state. This principle can be used in a first step to produce a precursor material from pure metals, in which case the metal corrosion / oxidation reaction and the coprecipitation reaction occur simultaneously within the same reactor. The overall reaction is shown by the following equation: xMe + yMe´(NO3) n + zHNO3 + (0.25xm - 2yn - 2z)O2 + (0.5xm + 2yn + z)H2O → Me x Me´ y (OH) (xm+yn) + (yn + z)NH3 wherein Me represents at least one metal selected from the group consisting of nickel, manganese, cobalt, aluminum, and magnesium, preferably in metallic form; Me´ represents at least one metal selected from the group consisting of nickel, manganese, cobalt, aluminum, magnesium, zirconium, yttrium, titanium, vanadium, and molybdenum, preferably in their ionic form; Me x Me´ y (OH) (xm+yn)represents the precursor product; x and y are the molar fractions of metals Me and Me´ respectively, where m is the molar weighted average valence of the mixed metal Me in the precursor product, n is the molar weighted average valence of the mixed metal Me´ in ionic form in the reactants, and z is the molar fraction of HNO3 introduced into the reaction system. In the formula, xm ≧ 8yn + 8z, x + y = 1, 1 ≧ x > 0, y ≧ 0, and z ≧ 0.

[0026] Oxygen, when used, can typically be used as an oxidizing agent as it does not produce any significant by-products during the reaction. Oxygen can be provided either as a pure oxygen source and / or as oxygen contained in other gases, such as oxygen in air.

[0027] Some metal nitrates may be included for use with elements that do not readily react with oxygen or for elements that are not easily handled during processing operations such as during stirring for homogeneous mixing or during magnetic separation of their metal forms.

[0028] Nitric acid can be used as an additional oxidizing agent and for buffering purposes to slow down the coprecipitation reaction of metal nitrates. Nitrate acid or its combination with ammonia can also be used for reactivating recycled raw materials. Ammonia is the only by-product when nitrates and nitric acid are used. However, the produced ammonia is in gaseous form and does not remain in the reaction system during operation. Therefore, in the above wet chemical method for preparing the precursor, no additional or new chemicals are added to the liquid after solid-liquid separation occurs. Therefore, the liquid can be directly reused in the reaction system with at least a maximum of 75%, more preferably at least a maximum of 90%, and even more preferably a maximum of 100% without having any adverse effects on the overall reaction.

[0029] The produced ammonia gas can be recovered as a useful chemical or chemical precursor for other industries, such as the fertilizer industry.

[0030] To obtain a high-quality product with consistent properties, the reactions described herein may be operated in a continuous mode where the reaction reaches steady-state conditions. This provides better control of the resulting chemical composition. In one approach, an artificial solution having the same or a similar composition as the liquid of the reaction system is prepared and used at the start of the reaction, and this artificial solution is used until the liquid produced from the solid-liquid separation operation is similar to the artificial solution.

[0031] The pH of the reaction slurry may be in the range of 7.5 to 13, or alternatively in the range of 8 to 12. The pH of the solution can be adjusted by adding any of the acids selected from sulfuric acid, nitric acid, or acetic acid, and / or by adding an alkaline substance selected from lithium hydroxide or lithium oxide, sodium hydroxide or sodium oxide, potassium hydroxide or potassium oxide, and ammonia. The pH adjustment can be carried out by adding an acid such as sulfuric acid or nitric acid, and / or by adding an alkaline substance such as lithium hydroxide or sodium hydroxide to the reaction mixture. It should be noted that lower pH values may reduce the quality of the coprecipitation product, while higher pH values may cause passivation of the metal during the corrosion reaction.

[0032] The reaction temperature may be in the range from 20 °C to the boiling point of the reaction slurry, including 20 °C to 100 °C.

[0033] Maintaining an acceptable conductivity of the reaction system may also be important for controlling the corrosion reaction. Thus, the reaction slurry may also contain a dissolved salt to form an electrolyte for conductivity. The salt may include salts such as sulfates, acetates, nitrates, and chlorates, and cations selected from sodium, lithium, potassium, and ammonium. The salt may be reusable in the recycled liquid recovered after separation of the liquid and solid.

[0034] To produce a final lithium compound having good performance, such as high capacity, the precursor material may have small primary particles in each secondary particle, i.e., a high BET (Brunauer-Emmett-Teller) surface area. When nitrates are used as oxidants and / or doping elements are required, nitrates should generally be present in the reaction system. Therefore, chemical reactions involving metal dissolution and precipitation should proceed well in the reaction system using only nitrates as anions. However, the BET surface area of the precursor material is usually extremely low with only nitrates in the reaction system. To increase the BET surface area, at least one additional selected anion and / or additive can be applied to the reaction system, which can change the pattern of precursor particle growth. These additional anions may be selected from borates, bromides, iodides, chlorides, sulfates, formates, or acetates, etc. Considering that the impurity level in the final product may increase when more anions and / or additives are introduced into the reaction system, i chemical substances decomposable during the high-temperature lithiation process, such as acetates, may be selected.

[0035] Ammonium generally must be present in the reaction system as a cation. However, other cations can also be applied to the reaction system to adjust the pH and conductivity. Considering that the impurity level in the final product may increase when more cations are introduced into the reaction system, lithium ions may be selected as the main cation in the final product. The aqueous solution may contain at least one additional cation in addition to ammonium such as sodium, potassium, and lithium. Lithium ions may be selected as the main cation in the final product.

[0036] The reaction slurry may also typically contain a dissolved complexing agent such as a mixture of ammonia and ammonium that can chelate with metal ions in an aqueous solution. The overall function of these complexing agents or chelating agents is to control the properties of the coprecipitation product and activate the metal towards corrosion reactions. This is to make it active against corrosion reactions.

[0037] The method for producing the cathode active material may also include a step of reactivating unreacted starting metal recovered from the slurry, for example, by grinding and / or washing, by using, for example, nitrate acid or a combination thereof with ammonia.

[0038] Furthermore, the method may also include a step in which solid particles having the same or a similar composition as the precursor product but having a smaller particle size than the precursor product are introduced into the reaction system at the start and / or during the reaction.

[0039] Embodiments of the methods described herein can thus be used to produce particles that are compositionally similar to the cathode active material precursor and have a uniform elemental distribution within each particle, where the metals are added in a stable continuous process in a single-stage reaction system. However, the method can also be applied to produce particles having a non-uniform elemental distribution within each particle, such as a compositional gradient or layered particles of the cathode active material precursor in a multi-stage reaction system, by adding different metals at different times or in different stages. In such a multi-stage system, each stage can deposit layers of materials having different compositions for different functions. For example, the core region of the cathode active material particles can be nickel-rich for higher capacity, while the surface area can be rich in manganese, cobalt, magnesium, tungsten, or aluminum for a stable interface with the electrolyte solution seen in lithium-ion batteries.

[0040] Accordingly, embodiments of the method provide a system in which metals are continuously added either always at the same ratio to produce a precursor having a uniform elemental distribution within each particle or metals are continuously added at different ratios over time to produce a precursor having a non-uniform elemental distribution within each particle.

[0041] The final cathode active material produced by the present invention can then be finally obtained by mixing the precursor compound with a lithium-containing compound and performing a firing reaction, which can optionally be followed by a surface treatment if necessary. This method is commonly referred to as lithiation, and this lithiation method is typically carried out as a solid-phase reaction at a temperature of 600 °C to 1100 °C depending on the chemical composition of the final material. In the lithiation reaction step, oxidation conditions may also be required as part of the method. Air, oxygen, and nitrates may be used as oxidizing agents.

[0042] In most applications, lithium hydroxide and lithium carbonate may be used as the lithium source, with or without water of crystallization.

[0043] After lithiation, slight crushing / milling in a size reduction operation may be required to break up loose agglomerates formed during the lithiation process. Then, any surface treatment, such as washing to remove excess lithium hydroxide / lithium carbonate and other impurities and coatings to stabilize the surface of the material, may be necessary or desired.

[0044] In this way, the cathode material can be subjected to further processing after firing, which includes washing to remove excess lithium and other unwanted impurities and coating the cathode material for better performance in battery manufacturing and / or battery applications.

Examples

[0045] (Example 1) According to the above manufacturing method, an aqueous solution of about 2.2 L was prepared and transferred to a 3-liter reaction vessel equipped with a stirring and heating system. The aqueous solution contained sodium acetate at a concentration of about 1.0 M, sodium nitrate at a concentration of 0.2 M, and ammonium nitrate at a concentration of 0.1 M. While stirring the solution at a stirring speed of about 800 rpm, the solution was heated to a temperature of about 60 °C. The pH was adjusted by adding 28% ammonia solution and sodium hydroxide and controlled to about 10. About 100 grams of metallic nickel was added to the reaction vessel. After about 30 minutes, about 50 grams of ball-milled metal hydroxide powder was added to the reaction vessel as a seed. The metal hydroxide powder with a size of less than 1 μm in D50 contained mostly nickel, as well as small amounts of cobalt and manganese.

[0046] Nitric acid with a concentration of 68% was continuously introduced into the reaction vessel using a peristaltic pump, and 11 grams of metal powder with Ni:Co:Mn being 90:5:5 was manually introduced into the reaction vessel every hour. The pumping speed of the nitric acid pump was about 2.8 mL / h. The pumping speed was about 10% lower than the theoretical value required to react all the metal. This was because oxygen was drawn into the reaction system by the stirrer during the reaction, and this oxygen also participated in the reaction as another oxidizing agent.

[0047] Every 4 hours, about 200 mL of slurry was recovered from the reaction vessel, and the recovered slurry was magnetically separated. The separated magnetic part was returned to the reaction vessel. The non-magnetic solid part was filtered and then washed with water. All the filtrate was returned to the reaction vessel together with the washing water.

[0048] The above operations were repeated continuously for 3 days. The final solid part of the filtration process was dried at about 120 °C for about 5 hours or more as the precursor of the present invention. This solid sample was sent for a scanning electron microscope (SEM) and BET surface area test. Figure 1 shows an SEM image of the sample recovered on the precursor particles from the above reaction. The particles are smooth spheres with fine secondary particles. The BET surface area was about 17 m 2 / g.

[0049] (Example 2 (Comparison)) For comparison, a second experiment was conducted. This was the same as the reaction conditions described in Example 1. The only significant difference was that the aqueous solution contained only nitrate as the anion in the reaction system, i.e., sodium nitrate at a concentration of about 1.2 M and ammonium nitrate at a concentration of 0.1 M. Figure 2 shows the SEM image on the precursor particles of the sample recovered from this example. The particles are spiky with very coarse secondary particles. The BET surface area was only 3.3 m 2 / g. Such a type of product is generally considered not suitable as a precursor for producing a lithium metal oxide cathode material.

[0050] (Example 3 (Reactivation)) Approximately 300 g of unreacted wet metal powder after magnetic separation was collected and exposed to air for 3 days. Approximately 100 g of the exposed metal powder was directly introduced into a 3 L container with stirring. The container contained approximately 2.5 L of filtrate recovered from the solid-liquid separation step of the method. The oxidation-reduction potential (ORP) was measured at different times from the introduced metal powder. Usually, an ORP less than the level of -300 mV indicates that the metal is active, and the test results are shown as curve 1 in Figure 3. The ORP was stable at approximately -120 mV, indicating that the metal powder was inactive.

[0051] In another test, approximately 100 g of the same exposed metal powder was introduced into 200 mL of 0.1 M NH4NO3 solution whose pH was adjusted to approximately 10.5 by adding ammonia. After stirring for several minutes, the metal powder was transferred to a 3 L container with stirring. Again, the container contained approximately 2.5 L of filtrate recovered from the solid-liquid separation step of the method. The ORP was measured at different times from the transferred metal powder. The test results are shown as curve 2 in Figure 3. The ORP rapidly decreased to -400 mV within 10 minutes, indicating that the inactive metal powder was activated.

[0052] Accordingly, it is apparent that the present invention provides a method, a product, and a battery that fully meet the above objectives, targets, and advantages. Thus, while specific embodiments of the present invention have been described, it will be understood that alternative, modified, and variant forms may be suggested to those skilled in the art, and that this specification is intended to embrace all such alternative, modified, and variant forms that fall within the scope of the appended claims.

Claims

1. A method for producing a positive electrode active material, comprising: providing an aqueous solution having a pH greater than 7; adding a first metal to the aqueous solution to form a reaction solution, wherein the first metal is selected from the group consisting of nickel, manganese, cobalt, aluminum, magnesium, and combinations thereof; forming a product solution comprising adding an oxidizing agent and a second metal to the reaction solution, wherein the second metal is selected from at least two elements from the group consisting of nickel, manganese, cobalt, aluminum, magnesium, zirconium, yttrium, titanium, vanadium, molybdenum, and combinations thereof, the product solution comprising a positive electrode active material precursor, and the positive electrode active material precursor product comprising the first metal and the second metal, wherein the first metal and the second metal are not the same; isolating the positive electrode active material precursor from at least a portion of the product solution to thereby form a filtrate.

2. The method according to claim 1, further comprising adding a mixed metal hydroxide to the aqueous solution.

3. The method according to claim 1, wherein the aqueous solution has a pH of from about 7.5 to about 13.

4. The method according to claim 1, wherein the aqueous solution further comprises an acid selected from the group consisting of sulfuric acid, nitric acid, acetic acid, or combinations thereof.

5. The method according to claim 1, wherein the aqueous solution further comprises an alkaline substance selected from the group consisting of lithium hydroxide, lithium oxide, sodium hydroxide, sodium oxide, potassium hydroxide, potassium oxide, and ammonia.

6. The method according to claim 1, wherein the aqueous solution further comprises a conductive salt.

7. The method according to claim 6, wherein the conductive salt is selected from the group consisting of sulfates, acetates, nitrates, chlorates, and combinations thereof.

8. The method according to claim 6, wherein the conductive salt comprises a cation selected from the group consisting of sodium, lithium, potassium, ammonium, and combinations thereof.

9. The method according to claim 1, wherein the aqueous solution further comprises an additional anion.

10. The method according to claim 9, wherein the additional anion is selected from the group consisting of borates, bromides, iodides, chlorides, sulfates, formates, acetates, and combinations thereof.

11. The method according to claim 1, wherein the aqueous solution contains cations.

12. The method according to claim 11, wherein the cation is selected from the group consisting of sodium, potassium, lithium, and combinations thereof.

13. The method according to claim 1, wherein the aqueous solution further contains a complexing agent.

14. The method according to claim 13, wherein the complexing agent contains ammonia and ammonium.

15. The method according to claim 1, wherein the step of forming the product solution further includes stirring the reaction solution.

16. The method according to claim 1, wherein the product solution is continuously formed under substantially steady-state conditions.

17. The method according to claim 1, wherein the step of forming the product solution further includes adding precursor particles of the positive electrode active material to the reaction solution.

18. The method according to claim 1, further including a step of recombining the filtrate with the product solution.

19. The method according to claim 18, wherein at least 90% of the liquid of the filtrate is recombined with the product solution.

20. The method according to claim 18, wherein the filtrate is directly recombined with the product solution.

21. The method according to claim 1, wherein the oxidizing agent is selected from the group consisting of oxygen, nitric acid, and combinations thereof.

22. The method according to claim 1, further including a step of isolating unreacted metals containing the first metal and the second metal from the filtrate, and a step of treating the unreacted metals with an acid.

23. The method according to claim 22, wherein the acid is selected from the group consisting of nitric acid, ammonia, ammonium, and combinations thereof.

24. The method according to claim 22, further including a step of additionally treating the unreacted metals, wherein the additional treatment is selected from the group consisting of pulverization, washing, and combinations thereof.

25. The method according to claim 1, wherein the positive electrode active material precursor includes precursor particles having a substantially uniform metal element distribution within each particle.

26. The method according to claim 1, wherein the positive electrode active material precursor includes precursor particles having a substantially non-uniform metal element distribution within each particle.

27. The method according to claim 26, wherein the substantially non-uniform metal element distribution within each particle is selected from the group consisting of gradient distribution, layered distribution, and combinations thereof.

28. forming a final mixture comprising the isolated cathode active material precursor and the lithium-containing compound; the method of claim 1, further comprising firing the final mixture to thereby form a fired final mixture comprising a cathode active material.

29. The method of claim 28, wherein the final mixture further comprises a dopant.

30. The method of claim 28, wherein the lithium-containing compound is selected from the group consisting of lithium hydroxide, lithium carbonate, and combinations thereof.

31. The method of claim 28, wherein the firing is performed at a temperature of about 600 °C to about 1100 °C.

32. The method of claim 28, further comprising treating the cathode active material, wherein the treatment is selected from the group consisting of washing, coating, and combinations thereof.

33. A method of forming an energy storage device, comprising: forming a cathode, wherein forming the cathode comprises depositing the cathode active material according to claim 28 on a current collector; inserting the cathode, an anode, and a separator into a housing, wherein the separator is disposed between the anode and the cathode.

34. A lithium mixed metal oxide product for use as a cathode active material for a lithium ion secondary battery, the mixed metal oxide product being produced according to the method of any one of claims 1 to 33.

35. A secondary lithium battery comprising a lithium metal oxide as a cathode material, wherein the cathode material is a mixed metal oxide product produced according to the method of any one of claims 1 to 33.

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