Method for manufacture cathode active materials for rechargeable batteries

Abstract

The present disclosure relates to a method for manufacture a very high Ni NMC cathode active material at large scale and at low cost. The method involves a double sintering step using Li2CO3 and LiOH as lithium sources. The very high nickel NMC material obtainable by this method can be used as a cathode active material for lithium batteries for an electric vehicle or hybrid electric vehicle.

Description

METHOD FOR MANUFACTURE CATHODE ACTIVE MATERIALS FOR RECHARGEABLE BATTERIESTECHNICAL FIELD

[0001] The present disclosure relates to a method for manufacture a very high Ni NMC material at large scale and at low cost. The method involves a double sintering step using U2CO3 and LiOH as lithium sources. The very high nickel NMC material obtainable by this method can be used as a cathode active material for lithium batteries for an electric vehicle or hybrid electric vehicle.BACKGROUND ART

[0002] Modern batteries require high energy density as well as long cycle life, especially for automotive applications. Currently, NMC (lithium-nickel-manganese-cobalt oxide) or NCA (lithium-nickel-cobalt-aluminium oxide) material are the most promising cathode active materials used in batteries for automotive applications.

[0003] NMC materials comprise particles, usually of spherical shape, and according to the formula Lii+a(NibMncCod)i-aO2. NMC materials can be understood as a solid state solution of LiCoO2, LiNio.5Mno.5O2 and LiNiO2. Accordingly, the reversible capacity of any NMC material can be estimated from the reversible capacities of LiCoO2, LiNio.5Mno.5O2 and LiNiCh. For example, NMC 622 (LiNi0.eMn0.2Co0.2O2) presents an expected reversible capacity of about 184 mAh / g. The reversible capacity of the NMC material tends to increase as the Ni content increases. For example, NMC 622 (LiNi0.eMn0.2Co0.2O2) presents a higher reversible capacity compared to NMC 442 (LiNi0.4Mn0.4Co0.2O2), meaning that less weight or volume is required to achieve a certain energy demand. Due to the lower price of nickel compared to cobalt, the NMC material with a higher Ni content and a lower Co content results in a more affordable cathode active material.

[0004] In the context of this disclosure, the term "high Ni NMC" refers to NMC materials wherein the Ni content (b in the previous formula above) is at least 0.4 and lower than 0.8. The term "very high Ni NMC" refers to NMC materials wherein b is at least 0.8, for example Li N i0.9M n0.05Co0.05O2.

[0005] NMC materials can present different crystalline morphologies, for example monolithic or polycrystalline. Usually, NMC materials comprising monolithic particles present better cycling stability compared to the polycrystalline material, see Niu et al, Materials Chem. and Physics, Volume 260, 15.02.2021, 124046. During the charging and / or discharging of Li-ion rechargeable batteries, polycrystalline particles may suffer from cracking along their grain boundaries under stringent operation conditions, which may lead to the increased contact area between electrolyte and cathode active material powder resulting in additional side reactions and even increase of the charge transfer resistance. In order to overcome theseshortcomings, monolithic particles, which are hereby defined as particles consisting of at least one primary particle and at most twenty primary particles, may be utilized. Monolithic particles can maintain their morphological integrity in the absence of anisotropic forces even if operated under extreme conditions and reduce gas evolution during electrochemical cycling,

[0006] A general process for manufacture NMC materials comprises sintering a blend of a mixed metal hydroxide precursor, for example Nio.33Mno.33Coo.33(OH)2, and a lithium precursor, at high temperatures in a continuous manner to achieve the lithium mixed metal oxide, for example LiNi0.33Mn0.33Co0.33O2 (NMC 111). It is desirable to optimize the process to obtain a cathode active material with a specific Li stoichiometric, a specific layered crystal structure and having a particular degree of crystallinity (crystalline size) and low level of impurities (soluble bases).

[0007] Impurities, such as sulfate or carbonate salts, known as soluble bases, often remain in the final NMC material causing gas generation in the cells (bulging) resulting in a poor cycling properties and also safety issues.

[0008] Although some NMC materials, such as NMC 111, can be manufacture at large scale under air atmosphere and using Li2COs as lithium source and with a single firing step, the manufacture of NMC with a higher Ni content becomes more challenging due to a thermodynamic limitation. As the Ni content increases, it is more difficult to obtain a cathode active material with low content of soluble bases, particularly Li2COs, see US7648693. For high Ni NMC, usually it is required a CCh-free oxidizing gas (typically oxygen), and also LiOH as lithium precursor.

[0009] Kim et al, J. of Power Sources, 601, 2024, 234300 discloses a method for small scale preparation of a very high Ni NMC (LiNi0.9Co0.05Mn0.05O2) obtainable by sintering a mixture of Nio.9oCoo.o5Mno.os(OH)2 and LiOH.

[0010] WO2017042655 discloses that the direct sintering (or single firing) method is not a viable option at high throughput to obtain a very high Ni NMC material, for example LiNi0.8Mn0.1Co0.1O2 (NMC 811). According to WO2017042655, when scaling up the production, the concentration of soluble bases remaining in the cathode active material is high. In order to avoid that, WO2017042655 discloses a method comprising two separate sintering steps using LiOH as lithium source. Additionally, it discloses that certain parameters, such as the sintering temperature and / or the crystalline size, are crucial to obtain NMC 811 with low level of impurities and optimal electrochemical properties.

[0011] Han et al, J. of Energy Storage, Volume 67, 1 September 2023, 107541 also discloses a method to obtain LiNi0.9Co0.05Mn0.05O2 via double sintering step using LiOH as lithium source.

[0012] The higher price of LiOH compared to Li2COs has a direct impact in the manufacture cost of very high Ni NMC materials.

[0013] Therefore, there is a need to provide an economical and efficient manufacturing process at large scale for very high Ni NMC materials with low level of soluble bases.

[0014] It is a first object of the present disclosure to provide a lithium deficient precursor for very high Ni NMC materials with low level of soluble bases.

[0015] It is the second object of the disclosure to provide a method for manufacturing a very high Ni NMC comprising monolithic particles at low cost.

[0016] It is the third object of the disclosure to provide a cathode active material obtainable by a method according to the present disclosure, wherein the cathode active material has an improved stability.

[0017] It is the fourth object of the present disclosure to provide the use of U2CO3 to reduce the manufacturing cost of very high Ni NMC material for cathode active material according to the present disclosure.

[0018] It is the fifth object of the present disclosure to provide a battery comprising a cathode active material according to the present disclosure, for an electric vehicle or hybrid electric vehicle.SUMMARY

[0019] The first object is achieved by providing a lithium deficient precursor powder comprising Li, M and O, wherein M comprises nickel in an atomic content x, wherein 0.80 < x < 0.95 relative to M; manganese in an atomic content y, wherein 0.025 < y < 0.15 relative to M; cobalt in an atomic content z, wherein 0.025 < z < 0.15 relative to M; wherein x+y+z is 1, wherein the content of Li, Ni, Mn and Co is determined by ICP-OES, and wherein the Li / M atomic ratio is between 0.45 and 0.60.

[0020] It has been found that by sintering a blend comprising a mixed metal hydroxide precursor with Li2COs with a Li / M atomic ratio between 0.45 and 0.60, it is possible to achieve a lithium deficient precursor powder with a low content of soluble bases.

[0021] The second object is achieved by providing a method comprising the following steps: providing a metal based precursor prepared from co-precipitation of metal sulphates with a base, mixing the metal based precursor with Li2COs obtaining a first mixture, wherein the Li / (Ni, Mn and Co) atomic ratio of the first mixture is between 0.45 to 0.60, sintering the first mixture under an oxidizing atmosphere at a temperature between 750 °C to 890 °C, for a time between 1 to 12 hours, obtaining a lithium deficient precursor powder, mixing the lithium deficient precursor powder with LiOH to obtain a second mixture,sintering the second mixture under O2 atmosphere at a temperature between 800 °C to 1000 °C for a time between 6 to 14 hours to obtain a sintered second mixture, milling the sintered second mixture to obtain a milled powder, heating the milled powder at a temperature between 750 °C to 800 °C to obtain the cathode active material.

[0022] The process according to this disclosure comprises two sintering steps. The first sintering step promotes the formation of a Li-deficient precursor with low content of soluble bases and useful for the manufacture of a very high Ni NMC at high throughput and low cost. The mixed metal precursor is blended with lithium carbonate in a Li-deficient stoichiometry, with a Li / (N i, Mn and Co) atomic ratio less than 1, for example 0.5. Then, in a second sintering step, the lithium deficient precursor is blended with lithium hydroxide in order to correct the Li / (Ni, Mn and Co) atomic ratio to about 1. By following this process, it is possible to achieve very high Ni NMC, for example LiNi0.9Co0.05Mn0.05O2 with a low soluble base content and at large scale production.

[0023] Moreover, the Li-deficient sintered precursor is obtained using Li2COs as a lithium source, which is more economically viable than LiOH. Additionally, it has been found that when the first mixture is heated at a temperature equal or higher than 900 °C, there is excessive crystal growth of the lithium deficient precursor and the powder particles agglomerate in an irreversible manner, reducing the specific surface area of the particles and negatively affecting the electrochemical properties of the resulting cathode active material, see Figures 1 and 2.

[0024] The third object is achieved by providing a cathode active material obtainable by the method according to the present disclosure.

[0025] The fourth object is achieved by providing a use of Li2COs to reduce the manufacturing cost of the cathode active material according to the present disclosure.

[0026] The fifth object is achieved by providing a battery comprising the cathode active material according to the present disclosure.FIGURES

[0027] Figure 1 illustrates the lithium deficient precursor powder obtained after heating the first mixture at 650 °C, as described for Example 1.

[0028] Figure 2 illustrates the lithium deficient precursor particle powder obtained after heating the first mixture at 900°C, as described for Comparative Example 1. As it can be observed, the particle powders are agglomerated.DETAILED DESCRIPTION

[0029] In the following detailed description, preferred embodiments are described in detail toenable the practice of the present invention. Although the present invention is described with reference to these specific preferred embodiments, it will be understood that this invention is not limited to these preferred embodiments. On the contrary, this invention includes numerous alternatives, modifications and equivalents as will become apparent from the consideration of the description and accompanying drawings. The different parts of the description and drawings are not intended to be read as isolated disclosures. That is, unless the context dictates otherwise, each alternative, modification, and equivalent may be combined with any other alternative, modification, or equivalent.

[0030] The following terms are intended to have the meaning presented below and are useful in understanding the description and intended scope of this disclosure.

[0031] The term "comprising", as used herein and in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps, or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a composition comprising components A and B" should not be limited to compositions consisting only of components A and B. It means that with respect to the present disclosure, the only relevant components of the composition are A and B. Accordingly, the terms "comprising" and "including" encompass the more restrictive terms "consisting essentially of" and "consisting of".

[0032] The term "cathode active material" (also known as CAM or positive electrode active material) refers to a material which is electrochemically active in a positive electrode or cathode. By active material, it must be understood to be a material capable of capturing and releasing Li ions when subjected to a voltage change over a predetermined period of time.

[0033] In the framework of the present disclosure, at% signifies atomic percentage. The at% or "atomic percent" of a given element expression of a concentration means how many percent of all atoms in the concerned compound are atoms of said element. The designation at% is equivalent to mol% or "molar percent".

[0034] The term "monolithic particles" refers to particles containing only one primary particle, as observed in a SEM image. The term "polycrystalline particles" refers to a particles comprising a bundle of primary particles, as observed in a SEM image. In particular, the term monolithic particles consist of at least one primary particle and at most twenty primary particles.

[0035] The term "about", as defined here, refers to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of + / -20% or less, preferably + / -10% or less, more preferably + / -5% or less, even more preferably + / - 1% or less, and still more preferably + / -0.1% or less of and from the specified value, in so far such variations are appropriate to perform in the present disclosure. However, it is to be understood that the value to which the modifier "about" refers is itself also specifically disclosed.Lithium deficient precursor

[0036] In a first aspect, the disclosure relates to a lithium deficient precursor powder for manufacture a cathode active material comprising a very high Ni NMC material.

[0037] In one embodiment, the disclosure provides a lithium deficient precursor powder comprising Li, M and O, wherein M comprises nickel in an atomic content x, wherein 0.80 < x < 0.95 relative to M; manganese in an atomic content y, wherein 0.025 < y < 0.15 relative to M; cobalt in an atomic content z, wherein 0.025 < z < 0.15 relative to M; wherein x+y+z is 1, wherein the content of Li, Ni, Mn and Co is determined by ICP-OES, and wherein the Li / M atomic ratio is between 0.45 and 0.60.

[0038] In one embodiment, the disclosure provides a lithium deficient precursor powder, wherein 0.83 < x < 0.93 relative to M. In another embodiment, the disclosure provides a lithium deficient precursor powder, wherein 0.87 < x < 0.93 relative to M. For example, x is 0.87, 0.88, 0.89, 0.90, 0.91, 0.92 or 0.93 relative to M.

[0039] In one embodiment, the disclosure provides a lithium deficient precursor powder, wherein 0.03 < y < 0.12 relative to M. In another embodiment, the disclosure provides a lithium deficient precursor powder, wherein 0.03 < y < 0.08 relative to M. For example, y is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08 relative to M.

[0040] In one embodiment, the disclosure provides a lithium deficient precursor powder, wherein 0.03 < z < 0.12 relative to M. In another embodiment, the disclosure provides a lithium deficient precursor powder, wherein 0.03 < z < 0.08 relative to M. For example z is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08 relative to M.

[0041] In one embodiment, the disclosure provides a lithium deficient precursor powder, wherein the Li / M atomic ratio is between 0.48 and 0.55. For example, the Li / M atomic ratio is 0.48, 0.49, 0.50, 0.51 or 0.52.

[0042] In one embodiment, the disclosure provides a lithium deficient precursor powder comprising particles having a crystalline size between 30 and 260 nm, wherein the crystalline size is calculated by the Williamson-Hall (W-H) method. In another embodiment, the crystalline size is between 40 and 150 nm. For example, the crystalline size is 41 nm, 42 nm, 43 nm, 44 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm or 150 nm.

[0043] In one embodiment, the disclosure provides a lithium deficient precursor powder, wherein x is 0.9 relative to M, y is 0.05 relative to M, z is 0.05 relative to M, the Li / M atomic ratio is 0.5, and the particles have a crystalline size between 50 nm and 150 nm.

[0044] The present disclosure also relates to a method for manufacture a lithium deficient precursor powder for a cathode active material comprising a very high Ni NMC material.

[0045] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder comprising Li, M and O, wherein M comprises nickel in an atomic content x, wherein 0.80 < x < 0.95 relative to M; manganese in an atomic content y, wherein 0.025 < y < 0.15 relative to M; cobalt in an atomic content z, wherein 0.025 < z < 0.15 relative to M; wherein x+y+z is 1, wherein the content of Li, Ni, Mn and Co is determined by ICP-OES, the Li / M atomic ratio is between 0.45 and 0.60, and wherein the method comprises the following steps: providing a metal-based precursor prepared from co-precipitation of metal sulphates with a base, mixing the metal-based precursor with Li2COs obtaining a mixture, and sintering the mixture under an oxidizing atmosphere at a temperature between 750 °C to 890 °C, for a time between 1 to 12 hours, obtaining a lithium deficient precursor powder.

[0046] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein 0.83 < x < 0.93 relative to M. In another embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein 0.87 < x < 0.93 relative to M. For example, x is 0.87, 0.88, 0.89, 0.90, 0.91, 0.92 or 0.93 relative to M.

[0047] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein 0.03 < y < 0.12 relative to M. In another embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein 0.03 < y < 0.08 relative to M. For example, y is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08 relative to M.

[0048] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein 0.03 < z < 0.12 relative to M. In another embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein 0.03 < z < 0.08 relative to M. For example, z is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08 relative to M.

[0049] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein the Li / M atomic ratio is between 0.48 and 0.55. For example, the Li / M atomic ratio is 0.48, 0.49, 0.50, 0.51 or 0.52.

[0050] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder comprising particles having a crystalline size between 30 and 260 nm, wherein the crystalline size is calculated by the Williamson-Hall (W-H) method. In another embodiment, the crystalline size is between 40 and 150 nm. For example, the crystalline size is 41 nm, 42 nm, 43 nm, 44 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm or 150 nm.

[0051] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein x is 0.9 relative to M, y is 0.05 relative to M, z is 0.05 relative to M, the Li / M atomic ratio is 0.5, and the particles have a crystalline size between 50 nm and 150 nm.

[0052] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein the metal-based precursor is prepared from coprecipitation of metal sulphates with NaOH or Na2COs.

[0053] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein the mixture is sintered at a temperature between 750 °C to 880 °C. In another embodiment, the temperature is between 780 °C to 850 °C. For example at 780 °C, 790 °C, 800 °C, 810 °C, 820 °C, 825 °C, 830 °C, 840 °C or 850 °C.

[0054] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein the mixture is sintered for a time between 1 to 10 hours. For example for 1 hour, 2 hours, 3 hours, 4 hours, 5 hours or 6 hours.

[0055] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein the mixture is sintered under CCh-free oxidizing atmosphere.

[0056] In one embodiment, the disclosure provides a method for manufacture a lithium deficient precursor powder, wherein the mixture is sintered under dry air or O2 atmosphere.

[0057] The present disclosure also relates to the use of a lithium deficient precursor powder for manufacture a cathode active material comprising a very high Ni NMC material.

[0058] In one embodiment, the disclosure relates to the use of a lithium deficient precursor powder for manufacture a cathode active material, wherein the lithium deficient precursor powder comprises Li, M and O, wherein M comprises nickel in an atomic content x, wherein 0.80 < x < 0.95 relative to M; manganese in an atomic content y, wherein 0.025 < y < 0.15 relative to M; cobalt in an atomic content z, wherein 0.025 < z < 0.15 relative to M; wherein x+y+z is 1, wherein the content of Li, Ni, Mn and Co is determined by ICP-OES, the Li / M atomic ratio is between 0.45 and 0.60.

[0059] In one embodiment, the disclosure relates to the use of a lithium deficient precursor powder for manufacture a cathode active material, wherein x is 0.9 relative to M, y is 0.05 relative to M, z is 0.05 relative to M, the Li / M atomic ratio is 0.5, and wherein the lithium deficient precursor powder comprises particles having a crystalline size between 50 nm and 150 nm.Method for manufacturing a very high Ni NMC material

[0060] In a second aspect, the present disclosure relates to a method for manufacture a cathode active material comprising a very high Ni NMC material comprising monolithic particles.

[0061] In one embodiment, the disclosure provides a method for manufacture a cathode active material comprising monolithic particles comprising Li, M' and O, wherein M' comprises nickel in an atomic content xl, wherein 0.80 < xl < 0.95 relative to M'; manganese in an atomic content yl, wherein 0.025 < yl < 0.15 relative to M'; cobalt in an atomic content zl, wherein 0.025 < zl < 0.15 relative to M'; wherein xl+yl+zl is 1, wherein the content of Li, Ni, Mn and Co is determined by ICP-OES, and the Li / M' atomic ratio is between 0.9 and 1.1; wherein the process comprises the following steps: providing a metal-based precursor prepared from co-precipitation of metal sulphates with a base, mixing the metal-based precursor with Li2COs obtaining a first mixture, wherein the Li / M' atomic ratio of the first mixture is between 0.45 to 0.60, sintering the first mixture under an oxidizing atmosphere at a temperature between 750 °C to 890 °C, for a time between 1 to 12 hours, obtaining a lithium deficient precursor powder, mixing the lithium deficient precursor powder with LiOH to obtain a second mixture, sintering the second mixture under O2 atmosphere at a temperature between 800 °C to 1000 °C for a time between 6 to 14 hours, milling the sintered second mixture to obtain a milled powder, andheating the milled powder at a temperature between 750 °C to 800°C to obtain the cathode active material.

[0062] In one embodiment, the disclosure provides a method for manufacture a cathode active material, wherein 0.83 < xl < 0.93 relative to M'. In another embodiment, 0.87 < xl< 0.93 relative to M'. For example, xl is 0.87, 0.88, 0.89, 0.90, 0.91, 0.92 or 0.93 relative to M'.

[0063] In one embodiment, the disclosure provides a method for manufacture a cathode active material, wherein 0.03 < yl < 0.12 relative to M'. In another embodiment, 0.03 < yl< 0.08 relative to M'. For example, yl is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08 relative to M'.

[0064] In one embodiment, the disclosure provides a method for manufacture a cathode active material, wherein 0.03 < zl < 0.12 relative to M'. In another embodiment, 0.03 < zl< 0.08 relative to M'. For example, zl is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08 relative to M'.

[0065] In one embodiment, the disclosure provides a method for manufacture a cathode active material, wherein the Li / M' atomic ratio is between 0.95 and 1.05. In another embodiment, the Li / M' ratio is between 1.0 and 1.05. For example, the Li / M' atomic ratio is 1.00, 1.01, 1.02, 1.03, 1.04 or 1.05.

[0066] In one embodiment, the disclosure provides a method for manufacture a cathode active material comprising monolithic particles and according to the general formula (I) LiwNix2Mny2Coz2O2, wherein 0.9 < w < 1.1; 0.80 < x2 < 0.95; 0.025 < y2 < 0.15; 0.025 < z2< 0.15; wherein x2+y2+z2 is 1, wherein the content of Li, Ni, Mn and Co is measured by ICP- OES; wherein the process comprises the following steps: providing a metal-based precursor prepared from co-precipitation of metal sulphates with a base, mixing the metal-based precursor with Li2COs obtaining a first mixture, wherein the Li / (Ni, Mn and Co) atomic ratio of the first mixture is between 0.45 to 0.60, sintering the first mixture under an oxidizing atmosphere at a temperature between 750 °C to 890 °C, for a time between 1 to 12 hours, obtaining a lithium deficient precursor powder, mixing the lithium deficient precursor powder with LiOH to obtain a second mixture, sintering the second mixture under O2 atmosphere at a temperature between 820 °C to 1000 °C for a time between 6 to 14 hours, milling the sintered second mixture to obtain a milled powder, and heating the milled powder at a temperature between 750 °C to 800 °C to obtain the positive electrode active material.

[0067] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein 0.83 < x2 < 0.93. In another embodiment, 0.87 < x2 < 0.93. For example, x2 is 0.87, 0.88, 0.89, 0.90, 0.91, 0.92 or 0.93.

[0068] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein 0.03 < y2 < 0.12. In another embodiment, 0.03 < y2 < 0.08. For example, y2 is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08.

[0069] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein 0.03 < z2 < 0.12. In another embodiment, 0.03 < z2 < 0.08. For example, z2 is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08.

[0070] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein w is between 0.95 and 1.05. In another embodiment, w is between 1.0 and 1.05. For example, w is 1.00, 1.01, 1.02, 1.03, 1.04 or 1.05.

[0071] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein the metal-based precursor prepared from co-precipitation of metal sulphates with NaOH or Na2COs.

[0072] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein the first mixture is sintered at a temperature between 760 °C to 880 °C. In another embodiment the temperature is between 780 °C to 850 °C. For example, at 780 °C, 790 °C, 800 °C, 810 °C, 820 °C, 825 °C, 830 °C, 840 °C or 850 °C.

[0073] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein the first mixture is sintered for a time between 1 to 10 hours. For example, for 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours.

[0074] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein the first mixture is sintered under dry air or O2 atmosphere.

[0075] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein second mixture is sintered at a temperature between 800 °C to 900 °C. For example, at 810 °C, 820 °C, 830 °C, 840 °C, 850 °C or 860 °C.

[0076] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein second mixture is sintered for atime between 6 to 12 hours. For example, for 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours.

[0077] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein the first mixture and / or second mixture are sintered under CCh-free oxidizing atmosphere.

[0078] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), further comprising the step of mixing the sintered second mixture with water to obtain an slurry.

[0079] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein the milling step is performed using a 10 mm diameter zirconia (ZrO?) balls for time between 10 to 20 hours.

[0080] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), further comprising the step of separating the zirconia balls and the milled product using a sieve and a filter to obtain a milled powder.

[0081] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein the milled powder is heated under oxygen atmosphere at a temperature between 700 to 800 °C to obtain a dried milled powder.

[0082] In one embodiment, the disclosure provides a method for manufacture a cathode active material according to the general formula (I), wherein the cathode active material comprises monolithic particles having a particle size distribution D50 between 3 pm and 5 pm. In another embodiment, the particle size distribution D50 between 3.5 pm and 4.1 pm. For example, D50 is 3.5 pm, 3.6 pm, 3.7 pm, 3.8 pm, 3.9 pm, 4.0 pm or 4.1 pm.

[0083] In one embodiment, the disclosure provides a method for manufacture a cathode active material comprising monolithic particles and according to the general formula (I), wherein particles have a crystalline size between 150 nm and 300 nm, wherein the crystalline size is calculated by the Williamson-Hall (W-H) method. In another embodiment, the crystalline size is between 180 nm and 250 nm. In another embodiment, the crystalline size is between 200 nm and 230 nm. In another embodiment, the crystalline size is between 210 nm and 220 nm. For example, the crystalline size is 210 nm, 211 nm, 212 nm, 213 nm, 214 nm, 215 nm, 216 nm, 217 nm, 218 nm, 219 nm or 220 nm.

[0084] In one embodiment, the disclosure provides a method for manufacture a cathode active material comprising monolithic particles and according to the general formula (I), wherein the particles have a crystalline volume between 30 A3and 40 A3. In another embodiment, the crystalline volume is between 33 A3and 34 A3. In another embodiment, the crystalline volume is between 33.86 A3and 33.90 A3.

[0085] In one embodiment, the disclosure provides a method for manufacture a cathode active material comprising monolithic particles and according to the general formula (I), comprising the following steps: mixing Nio.9oMno.osCoo.o5(OH)2 with U2CO3 for 30 minutes to obtain a first mixture with a Li / (Ni, Mn and Co) atomic ratio of about 0.5, heating the first mixture following a temperature profile from room temperature to 825 °C at 5 °C / min and holding the temperature at 825 °C for 2 hours to obtain a lithium deficient precursor powder, mixing the lithium deficient precursor powder with LiOH for 30 minutes to achieve a second mixture with a Li / (Ni, Mn and Co) atomic ratio of about 1, heating the second mixture following a temperature profile from room temperature to 830 °C at 5 °C / min and holding the temperature at 830 °C for 10 hours to obtain a productA. mixing product A with water to obtain a slurry, milling the slurry with 10 mm diameter zirconia (ZrC>2) balls for 15 hours, separating the zirconia balls and the slurry using a sieve and a filter to obtain a productB, and heating product B under oxygen atmosphere following a temperature profile from room temperature to 750 °C at 5 °C / min and holding the temperature at 750 °C for 14 hours to obtain a cathode active material.Cathode active material

[0086] In a third aspect, the disclosure provides a cathode active material obtainable by a method according to this disclosure.

[0087] In one embodiment, the cathode active material obtainable by the method of this disclosure comprises monolithic particles comprising Li, M' and O, wherein M' comprises nickel in an atomic content x2, wherein 0.80 < x2 < 0.95 relative to M'; manganese in an atomic content y2, wherein 0.025 < y2 < 0.15 relative to M'; cobalt in an atomic content z2, wherein 0.025 < z2 < 0.15 relative to M'; wherein x2+y2+z2 is 1, wherein the content of Li, Ni, Mn and Co is determined by ICP-OES, and the Li / M' atomic ratio is between 0.9 and 1.1.

[0088] In one embodiment, the disclosure provides a cathode active material obtainable by the method this disclosure, wherein 0.87 < x2 < 0.93 relative to M'. For example, x2 is 0.87, 0.88, 0.89, 0.90, 0.91, 0.92 or 0.93 relative to M'.

[0089] In one embodiment, the disclosure provides a cathode active material obtainable by the method of this disclosure, wherein 0.03 < y2 < 0.12 relative to M'. In another embodiment, 0.03 < y2 < 0.08 relative to M'. For example, y2 is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08 relative to M'.

[0090] In one embodiment, the disclosure provides a cathode active material obtainable by the method of this disclosure, wherein 0.03 < z2 < 0.12 relative to M'. In another embodiment, 0.03 < z2 < 0.08 relative to M'. For example, z2 is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08 relative to M'.

[0091] In one embodiment, the disclosure provides a cathode active material obtainable by the method of this disclosure, wherein the Li / M' atomic ratio is between 0.95 and 1.05. In another embodiment, the Li / M' atomic ratio is between 1.0 and 1.05. For example, the Li / M' atomic ratio is 1.00, 1.01, 1.02, 1.03, 1.04 or 1.05.

[0092] In one embodiment, the disclosure provides a cathode active material obtainable by the method of this disclosure, comprising monolithic particles and according to the general formula (I) LiwNix2Mny2CoZ2O2, wherein 0.9 < w < 1.1; 0.80 < x2 < 0.95; 0.025 < y2 < 0.15; 0.025 < z2 < 0.15; wherein x2+y2+z2 is 1, wherein the content of Li, Ni, Mn and Co is determined by ICP-OES.

[0093] In one embodiment, the disclosure provides a cathode active material obtainable by the method of this disclosure and according to the general formula (I), wherein 0.83 < x2 < 0.93. In another embodiment, 0.87 < x2 < 0.93. For example, x2 is 0.87, 0.88, 0.89, 0.90, 0.91, 0.92 or 0.93.

[0094] In one embodiment, the disclosure provides a cathode active material obtainable by the method of this disclosure and according to the general formula (I), wherein 0.03 < y2 < 0.12. In another embodiment, 0.03 < y2 < 0.08. For example, y2 is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08.

[0095] In one embodiment, the disclosure provides a cathode active material obtainable by the method of this disclosure and according to the general formula (I), wherein 0.03 < z2 < 0.12. In another embodiment, 0.03 < z2 < 0.08. For example, z2 is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08.

[0096] In one embodiment, the disclosure provides a cathode active material obtainable by the method of this disclosure and according to the general formula (I), wherein w is between 0.95 and 1.05. In another embodiment, w is between 1.0 and 1.05. For example, w is 1.00, 1.01, 1.02, 1.03, 10.4 or 1.05.

[0097] In one embodiment, the disclosure provides a cathode active material obtainable by the method of this disclosure and according to the general formula (I), wherein the cathode active material comprises particles having particle size distribution D50 between 3 pm and 5 pm. In another embodiment, the particle size distribution D50 is between 3.5 pm and 4.1 pm. For example, D50 is 3.5 pm, 3.6 pm, 3.7 pm, 3.8 pm, 3.9 pm, 4.0 pm or 4.1 pm.

[0098] In one embodiment, the disclosure provides a cathode active material obtainable by the method of this disclosure and according to the general formula (I), wherein the cathodeactive material comprises monolithic particles having a crystalline size between 150 nm and 300 nm, wherein the crystalline size is calculated by the Williamson-Hall (W-H) method. In another embodiment, the crystalline size is between 180 nm and 250 nm. In another embodiment, the crystalline size is between 200 nm and 230 nm. In another embodiment, the crystalline size is between 210 nm and 220 nm. For example, the crystalline size is 210 nm, 211 nm, 212 nm, 213 nm, 214 nm, 215 nm, 216 nm, 217 nm, 218 nm, 219 nm or 220 nm.

[0099] In one embodiment, the disclosure provides monolithic particles of LiNi0.9Mn0.05Co0.05O2 as a cathode active material obtainable by the method of this disclosure, wherein the cathode active material comprises monolithic particles having a crystalline size between 200 nm and 230 nm, and a particle size distribution D50 between 3 pm and 5 pm.Use of Li2COs

[0100] In a fourth aspect, the disclosure provides the use of Li2COs for the manufacture of a cathode active material comprising a very high Ni NMC material comprising monolithic particles.

[0101] In one embodiment, the disclosure provides the use of U2CO3 for the manufacture of a cathode active material comprising monolithic particles and having a general formula (II) LiW'Nix3Mny3Coz3O2, wherein 0.9 < w' < 1.1; 0.80 < x3 < 0.95; 0.025 < y3 < 0.15; 0.025 < z3 < 0.15; wherein x3+y3+z3 is 1, wherein the content of Li, Ni, Mn and Co is determined by ICP-OES, and wherein the cathode active material comprises monolithic particles having a crystalline size between 200 nm and 230 nm, and a particle size distribution D50 between 3 pm and 5 pm, wherein the crystalline size is calculated by the Williamson-Hall (W-H) method.

[0102] In one embodiment, the disclosure provides the use of Li2COs for the manufacture of LiNi0.9Mn0.05Co0.05O2 comprising monolithic particles, having a crystalline size between 200 nm and 230 nm, and a particle size distribution D50 between 3 pm and 5 pm.Battery

[0103] In a fifth aspect, the present disclosure relates to a battery comprising a cathode active material according to this disclosure.

[0104] In one embodiment, the disclosure provides a battery comprising LiNi0.9Mn0.05Co0.05O2 comprising monolithic particles, having a crystalline size between 200 nm and 230 nm, and a particle size distribution D50 between 3 pm and 5 pm.

[0105] While several embodiments have been listed above, the present disclosure is intended to include all the possible combinations of such embodiments. The skilled person in the art may combine embodiment from the first, second, third, fourth and fifth aspect of the present disclosure.EXPERIMENTAL TEST USED IN THE EXAMPLESCoin cell test

[0106] The NMC materials produced by the double sintering method according to this disclosure are electrochemically tested in a coin cell. The details are as follows: a half-cell (coin cell) is assembled by placing a separator (from Celgard) between the positive electrode and a piece of lithium metal as a negative electrode, and dropping an electrolyte of IM LiPFe in EC / DMC (3:7) between separator and electrodes. All the cell tests in the present disclosure follow the same procedure shown in Table 1. The C-rate is defined as 220 mAh / g. For example, 0.1C means that the cell will be charged or discharged in 10 hour. "E-Curr" and "V" stands for the end current and cut-off voltage, respectively. At the first cycle, the DQ0.1C (discharge capacity of the first cycle at a rate of 0.1C) and IRRQ (irreversible capacity) are determined. The rate performance can be calculated from the subsequent five cycles. The performance of cycle stability is obtained from cycle #7 to #35. The capacity fading at 0.1C is represented by "QfadeO.lC (% / 100)". With DQ7 and DQ34 referring to the discharge capacity of cycle #7 and #34 respectively, the "QfadeO.lC (% / 100)" could be obtained through the following formula: 100 x 100

[0107] This is similar for the capacity fading at 1C, which is noted as "QfadelC (% / 100)". With DQ8 and DQ35 referring to the discharge capacity of cycle #8 and #35 respectively, the "QfadelC (% / 100)" could be obtained through the following formula: 100 x 100Table 1. Coin cell testing procedureTitration test

[0108] Titration test was used to measure the content of LiOH and U2CO3 in the samples. 5 grams of the corresponding sample was weighed in a volumetric flask of 250 mL. 100 mL deionized water was added to the flask. The mixture was stirred using a magnetic stirrer at 720 rpm in a N2 atmosphere for 30 minutes and then filtered. Finally, the solution was used for titration with 0.01 molar of hydrochloric acid, as disclosed in US7648693.X-ray diffraction test

[0109] The crystallinity of NMC material is evaluated by determining the crystalline size and lattice strain from the X-ray diffraction pattern. The crystalline size, as a derivation from perfect crystallinity, leads to a broadening of a diffraction peak. It is the same case for strain, which is defined as a deformation of unit cell divided by its length, represented by Ad / d. The non-uniform lattice strain can cause the systematic shifts of atoms and lead to a peak broadening.

[0110] In "Acta Metallurgica, 1, 22-31 (1953)", Williamson and Hall proposed a method to extract the information on crystalline size and strain from the integral width of diffraction peaks. This method is based on the approximate relationship between Bragg angle (0) and peak broadening arising from crystalline size and lattice strain, with the following formula:where p represents the integral width of peak, e is the lattice strain, L is the crystalline size, A is the radiation wavelength, and C and K are constants, often taken as 4 and 0.9, respectively. By looking at the product of integral width (P) and cos 9 as a function of sin 9, the lattice strain and crystalline size can be estimated from the slope and intercept of a fitting line for this formula, respectively. The integral width (P) is the width of a rectangle having the same height (maximum intensity) and area (integrated intensity) of the selected diffraction peak. The area can be approximately integrated by a trapezoidal rule, and the height can be easily obtained from raw data of the diffraction pattern, thus it is feasible to estimate the integral width of each diffraction peak and further determine the crystalline size and lattice stain by this Williamson-Hall (W-H) method.

[0111] The crystalline size L and lattice strain e can be obtained from the intercept and slope, by the following formulas:where the y2 is defined as the product of p 2 and cos 9 2, yi is defined as the product of p 1 and cos 9 1. The X2 and xi are the value of sin 92 and sin 9 1 respectively.Inductively coupled plasma optical emission spectroscopy (ICP-OES)

[0112] ICP-OES is used to quantify the components present in the samples. Inductively ICP- OES measurements are performed on an Agilent 5110 ICP-OES spectrometer. Accordingly, 1 g of powder of the sample is dissolved in 50 mL hydrochloric acid in an Erlenmeyer flask. The flask is covered by glass and heated on a hot plate for complete dissolution of the material. After being cooled to room temperature, the solution is moved to a 500 mL volumetric flask that has been thoroughly cleaned and rinsed with distilled (DI) water. After filling the flask with the solution, the volumetric flask is filled with DI water up to the 500 mL mark, followed by complete homogenization. 5 mL solution is taken out with a 5 mL pipette and transferred into a 50 mL volumetric flask along with an internal standard for a second dilution, where the volumetric flask is filled with 10% hydrochloric acid up to the 50 mL mark and then homogenized. Finally, this 50 mL solution is used in the spectrometer.Carbon analysis

[0113] Carbon analysis has been used to quantify the carbon (C) content in the corresponding sample. The carbon content has a direct correlation with the carbonate salt content present in the sample. Carbon analysis was perform on Horiba EMIA-PRO. Samples were melted together with a melting agent (Lecocel II HP Leco 502-173) in a high frequency induction oven under a constant flow oxygen. The released carbon and sulfur react with the oxygen to form SO2 and CO2. These gasses are determined with a IR detector. A higher amount of CO2 detected is directly related with a higher amount of carbonate salts present in the sample.Particle size distribution (PSD)

[0114] PSD is measured using a Malvern Panalaytical Mastersizer 3000 with Hydro 2000MU after dispersing examples as described herein below of positive electrode active material powders in an aqueous medium. To improve the dispersion of the positive electrode active material powder examples, sufficient ultrasonic irradiation and stirring is applied, and an appropriate surfactant is introduced. The span being defined as (D90-D10) / D50, wherein D10, D50, and D90 being defined as particle sizes at 10%, 50%, and 90% of cumulative volume% distribution.Brunauer-Emmett-Teller (BET) analysis

[0115] The specific surface area (SSA) of the cathode active material is measured with the Brunauer-Emmett-Teller (BET) method by using a Micromeritics Tristar II 3020. A powder is heated at 300 °C under nitrogen (N2) gas for 1 hour prior to the measurement in order to remove adsorbed species. The dried powder is put into the sample tube. The sample is then de-gassed at 30 °C for 10 minutes. The instrument performs the nitrogen adsorption test at 77 K. By obtaining the nitrogen isothermal absorption / desorption curve, the total specific surface area of the sample in m2 / g is derived.EXAMPLES

[0116] The following examples illustrate the present disclosure in more detail.Example 1

[0117] Initially, 3.4 kg of U2CO3 and 17 kg of Nio.gMno.osCoo.os OH)? were homogenously blended in a Henschel Mixer® for 30 mins. Then, the first blended mixture was sintered at 650 °C for 2 hours under dry air. Dry air was continuously pumped into the sintering equipment at a flow of 40 L / min. After sintering, the sintered cake was crushed to obtain a lithium deficient precursor with a Li / (N i, Mn and Co) atomic ratio about 0.5, labelled as lithium deficient precursor 1 or Exl. Ex 1 was isolated and submitted to BET analysis.Example 2

[0118] Initially, 20 grams of U2CO3 and 100 grams of Nio.9Mno.osCoo.o5(OH)2 were homogenously blended in a Henschel Mixer® for 30 minutes. Then, the first blended mixture were sintered at 750 °C for 7 hours under dry air. Dry air was continuously pumped into the sintering equipment at a flow of 10 L / min. After sintering, the sintered cake was crushed to obtain a lithium deficient precursor with a Li / (Ni, Mn and Co) atomic ratio about 0.5, labelled as lithium deficient 2 or EX2. Ex 2 was isolated and subjected to carbon and titration analysis.Cathode active material 1

[0119] Ex2 was used as a precursor to obtain the cathode active material LiNi0.9Mn0.05Co0.05O2.

[0120] Ex2 was blended with LiOH to correct the Li stoichiometry to achieve a Li / (Ni, Mn and Co) atomic ratio about 1. The blending was done in a Henschel Mixer® for 30 minutes to obtain a second blended mixture. The blended mixture was sintered at 830 °C for 8 hours under O2 at a flow of 50 m3 / h. The resulted sintered product was transferred and mixed with water to obtain a slurry. The slurry was milled with 10 mm diameter zirconia (ZrC>2) balls for 15 hours. Then, the zirconia balls where separated from the slurry using a sieve and a filter to obtain a filtered product. The filtered product was heated under oxygen atmosphere following a temperature profile from room temperature to 750 °C at 5 °C / min and holding the temperature at 750 °C for 14 hours to obtain LiNi0.9Mn0.05Co0.05O2.Example 3

[0121] Initially, 20 grams of Li2COs and 100 grams of Nio.9Mno.o5Coo.os(OH)2 were homogenously blended in a Henschel Mixer® for 30 minutes. Then, the first blended mixture were sintered at 775 °C for 2 hours under dry air. Dry air was continuously pumped into the sintering equipment at a flow of 10 L / min. After sintering, the sintered cake was crushed to obtain a lithium deficient precursor with a Li / (N i, Mn and Co) atomic ratio about 0.55, labelled as lithium deficient 3 or EX3. Ex 3 was isolated and subjected to XR.D analysis.Comparative Example 1

[0122] Initially, 5.5 kg of Li2COs and 27.5 kg of Nio.9Mno.o5Coo.os(OH)2 were homogenously blended in a Henschel Mixer® for 30 minutes. Then, the first blended mixture were sinteredat 900 °C for 2 hours under O2. O2 was continuously pumped into the sintering equipment at a flow of 40 L / min. After sintering, the sintered cake was crushed to obtain a lithium deficient precursor with a Li / (Ni, Mn and Co) atomic ratio about 0.5, labeled as CExl.Comparative example 2

[0123] Initially, 25 grams of U2CO3 and 100 grams of Nio.9Mno.osCoo.o5(OH)2 were homogenously blended in a Henschel Mixer® for 30 minutes. Then, the first blended mixture were sintered at 750 °C for 7 hours under dry air in a pilot-scale equipment. Dry air was continuously pumped into the sintering equipment at a flow of 10 L / min. After sintering, the sintered cake was crushed to obtain a lithium deficient precursor with a Li / (Ni, Mn and Co) ratio about 0.625. The above lithium deficient precursor sample is labelled pCEx2. pCEx 2 was isolated and subjected to carbon and titration analysis.Cathode active material 2

[0124] Ex2 was used as a precursor to obtain the cathode active material LiNi0.9Mn0.05Co0.05O2. The lithium deficient precursor CEx2 was blended with LiOH to correct the Li stoichiometry to achieve a Li / (Ni, Mn and Co) ratio about 1. The blending was done in a Henschel Mixer® for 30 minutes to obtain a second blended mixture. The blended mixture was sintered at 830 °C for 8 hours under O2 at a flow of 50 m3 / h. After second sintering, the sintered cake was crushed to obtain a polycrystalline particles of LiNi0.9Mn0.05Co0.05O2.Comparative example 3

[0125] Initially, 30 grams of Li2COs and 100 grams of Nio.9Mno.o5Coo.os(OH)2 were homogenously blended in a Henschel Mixer® for 30 minutes. Then, the first blended mixture were sintered at 750 °C for 7 hours under dry air in a pilot-scale equipment. Dry air was continuously pumped into the sintering equipment at a flow of 10 L / min. After sintering, the sintered cake was crushed to obtain a lithium deficient precursor with a Li / (Ni, Mn and Co) ratio about 0.75. The above lithium deficient precursor sample is labelled CEx3. CEx 3 was isolated and subjected to carbon and titration analysis.Results and discussionTable II: Li / (Ni, Mn and Co) atomic ratio, sintering temperature of the first mixture, specific surface area and crystalline size of the lithium deficient precursor examples and comparative examples.

[0126] As can be observed, the specific surface area is adversely affected by the sinteringtemperature, see Exl versus CExl. Additionally, the sintering temperature also influence the crystalline size as measure by XRD analysis. Therefore, the method according to the invention provide lithium deficient precursors with optimal specific surface area and crystalline size. Powder particles with high specific surface area are associated with an increase of the interface between the cathode active material and the electrolyte, facilitating ion transport, and ultimately leading to faster charge / discharge rates. Additionally, particles with a high specific surface area are associated with better capacity retention due to a more uniform lithium distribution, see Thapa et al, Energies, 2022, 15, 8357.Table III: Li / (Ni, Mn and Co) atomic ratio, carbon and soluble base content of the lithium deficient precursor examples and comparative examples.

[0127] Titration experiments and carbon analysis experiments were preformed to quantify the level of soluble bases (impurities) present in the examples and comparative examples, see Table III. Particularly, carbon analysis is used to calculate the content of IJ2CO3 present in a sample; and titration experiments is used to calculate the content of LiOH and IJ2CO3 present in a sample.

[0128] All the samples were prepared under the same processing conditions. It has been demonstrated that the content of soluble bases significantly increases when IJ2CO3 is used as lithium source in a Li / (Ni, Mn and Co) ratio of 0.625 or higher, see CEx2 and CEX3 versus EX2 in Table III.

[0129] By increasing the Li / (Ni, Mn and Co) atomic ratio from 0.5 to 0.625, the concentration of soluble bases increases almost 4 fold. Moreover, when the Li / (Ni, Mn and Co) atomic ratio is 0.75, the content of soluble bases increases almost 9 fold.

[0130] Accordingly, there is direct correlation between the Li / (Ni, Mn and Co) atomic ratio and soluble bases content present in the lithium deficient precursor, which would adversely affect the cyclic capacity of the resulting cathode active material.

Claims

1. CLAIMS1. A lithium deficient precursor powder comprising Li, M and O, wherein M comprises nickel in an atomic content x, wherein 0.80 < x < 0.95 relative to M; manganese in an atomic content y, wherein 0.025 < y < 0.15 relative to M; cobalt in an atomic content z, wherein 0.025 < z < 0.15 relative to M; wherein x+y+z is 1, wherein the content of Li, Ni, Mn and Co is determined by Inductively coupled plasma optical emission spectroscopy, and wherein the Li / M atomic ratio is between 0.45 and 0.60, wherein the lithium deficient precursor powder comprises particles having a crystalline size between 30 nm and 260 nm as determined by the Williamson-Hall (W-H) method.

2. A lithium deficient precursor powder according to claim 1, wherein 0.87 < x < 0.93 relative to M; 0.03 < y < 0.08 relative to M; 0.03 < z < 0.08 relative to M, the Li / M ratio is between 0.45 and 0.55.

3. A method for manufacture a lithium deficient precursor powder according to claim 1 or 2, the method comprising the following steps:- providing a metal-based precursor prepared from co-precipitation of metal sulphates with a base,- mixing the metal-based precursor with Li2COs obtaining a mixture, and- sintering the mixture under an oxidizing atmosphere at a temperature between 750 °C to 890 °C, for a time between 1 to 12 hours to obtain the lithium deficient precursor powder.

4. A method for manufacture a cathode active material comprising monolithic particles comprising Li, M’ and O, wherein M’ comprises nickel in a atomic content xl, wherein 0.80 < xl < 0.95 relative to M’; manganese in a atomic content yl, wherein 0.025 < yl < 0.15 relative to M’; cobalt in a atomic content zl, wherein 0.025 < zl < 0.15 relative to M’; wherein xl+yl+zl is 1, wherein the content of Li, Ni, Mn and Co is measured by Inductively coupled plasma optical emission spectroscopy, and the Li / M’ atomic ratio is between 0.9 and 1.1; wherein the process comprises the following steps:- providing a metal-based precursor prepared from co-precipitation of metal sulphates with a base,- mixing the metal-based precursor with Li2COs obtaining a first mixture, wherein the Li / M' atomic ratio of the first mixture is between 0.45 to 0.60,- sintering the first mixture under an oxidizing atmosphere at a temperature between 750 °C to 890 °C, for a time between 1 to 12 hours, obtaining a lithium deficient precursor powder,- mixing the lithium deficient precursor powder with LiOH to obtain a second mixture,- sintering the second mixture under O2 atmosphere at a temperature between 800 °C to 1000 °C for a time between 6 to 14 hours,- milling the sintered second mixture to obtain a milled powder, and- heating the milled powder at a temperature between 750 °C to 800 °C to obtain the positive electrode active material.

5. A method according to claim 4, wherein the cathode active material is according to a general formula (I) LiwNix2Mny2CoZ2O2, wherein 0.9 < w < 1.1; 0.80 < x2 < 0.95; 0.025 < y2 < 0.15; 0.025 < z2 < 0.15; wherein x2+y2+z2 is 1.

6. A method according to claim 5, wherein 0.87 < x2 < 0.93.

7. A method according to claim 5 or 6, wherein 0.03 < y2 < 0.12.

8. A method according to any of the claims 5 to 7, wherein 0.03 < z2 < 0.12.

9. A method according to any of the claims 5 to 8, w is between 0.95 and 1.05.

10. A method according to any of the claims 4 to 9, wherein the cathode active material comprises monolithic particles having a crystalline size between 40 nm and 230 nm, wherein the crystalline size is calculated by the Williamson-Hall (W-H) method.

11. A method according to any of the claims 4 to 10, wherein the cathode active material comprises monolithic particles having a particle size distribution D50 between 3 pm and 5 pm.

12. A method according to any of the claims 4 to 11, wherein the first mixture is sintered at a temperature between 780 °C to 850 °C for a time between 1 to 10 hours, and second mixture is sintered at a temperature between 800 °C to 900 °C for a time between 6 to 12 hours.

13. A cathode active material obtainable by the method according to any of the claims 3 to 12.

14. A battery comprising a cathode active material according to claim 13.

15. The use of IJ2CO3 for the manufacture of a cathode active material according to claim

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