Cathode active material for rechargeable batteries

Abstract

The present invention relates to Li-rich Mn-rich cathode active material comprising high- valence transition metal ions, such as Mo, exhibiting high capacity comprising Li, M and O, wherein M comprises: Ni in a molar ratio x, wherein 0.10 ≤ x ≤ 0.50 relative to M; Mn in a molar ratio y, wherein 0.50 ≤ y ≤ 0.80 relative to M; and Mo in a molar ratio z, wherein 0.001 ≤ z < 0.05 relative to M; wherein the molar ratio of Li to M (Li / M) is between 1.00 and 1.60; and wherein the content of Li, Ni, Mn and Mo is measured by ICP-AES, and x+y+z is 1.00.

Description

DescriptionTitleCATHODE ACTIVE MATERIAL FOR RECHARGEABLE BATTERIESTECHNICAL FIELD OF THE INVENTION

[0001] This invention relates to a Li-rich and Mn-rich cathode active material for rechargeable batteries, in particular a Co-free cathode active material, to a process for manufacturing this cathode active material; and to a battery comprising said cathode active material.BACKGROUND OF THE INVENTION

[0002] Energy storage systems such as rechargeable batteries are necessary for quickly storing and releasing high amounts of energy to adjust power output to demand. The same battery technology goes into electric vehicles, which run on stored electrical energy and reduce pollution compared to conventional vehicles with internal combustion engines. To meet proper demands, these batteries need to store high levels of energy with minimal weight, charge and discharge at fast rates, and go through many cycles without diminishing in performance. These are respectively referred to as high energy density, rate capability, and cyclability, and the demands must be reached while the batteries remain affordable and safe. Particularly because of their high energy density and rate capability, many kinds of lithium-ion batteries (LIBs) are widely studied to meet these needs.

[0003] Lithium and manganese-rich (LMR) layered oxide is one of promising cathode active materials for lithium-ion batteries due to its low cost originated from relatively lower Co content. However, the cost of the LMR layered oxide has to be further decreased and its energy density should be further improved.

[0004] US20190020025A1 , US2020381728A1 and US2019013519A1 disclose LMR compositions such as Li1.5Ni0.157Co0.i67Mn0.666Mo0.01O2 as an example. It was shown in the prior art that the addition of Mo increases the initial discharge capacity. However, the compositions disclosed in the prior art still contain large amounts of Co, which makes the cathode active material more expensive, and the capacity values of the compositions should be improved.

[0005] Therefore, there remains a need to provide a Li-rich and Mn-rich cathode active material, which may be essentially Co-free or Co-free to make more affordable batteries with high capacity and low irreversible capacity.

[0006] It is an object of the present invention to provide a Li-rich and Mn-rich cathode active material having high capacity.

[0007] It is a further object of the present invention to provide a process for manufacturing said cathode active material.

[0008] It is a further object of the present invention to provide a battery comprising said cathode active material.SUMMARY OF THE INVENTION

[0009] In a first aspect, the object of the invention is achieved by providing a cathode active material for rechargeable batteries comprising Li, M and O, wherein M comprises: a. Ni in a molar ratio x, wherein 0.10 < x < 0.50 relative to M, b. Mn in a molar ratio y, wherein 0.50 < y < 0.80 relative to M, and c. Mo in a molar ratio z, wherein 0.001 < z < 0.05 relative to M, wherein the molar ratio of Li to M (Li / M) is between 1 .00 and 1 .60; and wherein the content of Li, Ni, Mn and Mo is measured by ICP-AES, and x+y+z is 1 .00.

[0010] In one embodiment of the invention, the cathode active material has a composition according to a general formula (I) LiwNixiMnyiMoziO2, wherein: 1.00 < w < 1 .60; 0.10 < x1 < 0.50; 0.50 < y1 < 0.80; 0.001 < z1 < 0.10; wherein the content of Li, Ni, Mn and Mo is measured by ICP-AES, and x1 +y1 +z1 is 1.00.

[0011] Inventors surprisingly found that a lithium and manganese rich cathode active material (LMR) comprising Mo shows a particular improvement over a LMR without Mo, in particular even when being essentially Co free. It drastically increased discharge capacity and also decreased the irreversible capacity, as shown in Table 2.

[0012] In a further aspect, the present invention provides a process for manufacturing said cathode active material through a solid-state synthesis route using a hydroxide precursor.

[0013] In a further aspect the present invention provides a battery comprising said cathode active material.BRIEF DESCRIPTION OF THE FIGURES

[0014] Further features and advantages of the invention can be ascertained from the following detailed description that is provided in connection with the figures described below:

[0015] Figure 1 is a cross-section image showing the Mo distribution of a secondary particle of an as-synthesized Example 3 material having a formula Lii.3i Nio.38Mno.6iMoo.oi02, as measured by transmission electron microscopy TEM.

[0016] Figure 2 is a cross-section image showing the Mo distribution in the grain boundaries between the primary particles of an as-synthesized Example 3 material having a formula Li1.31Ni0.38Mn0.6iMo0.01O2, as measured by TEM.

[0017] Figure 3 is a cross-section image showing Mo distribution in the center of a secondary particle between the primary particles of an as-synthesized Example 3 material having a formula Li1.31 Ni0.38Mn0.6iMo0.01O2, as measured by TEM.DETAILED DESCRIPTION

[0018] In the following detailed description, preferred embodiments are described in detail to enable practice of the invention. Although the invention is described with reference to these specific preferred embodiments, it will be understood that the invention is not limited to these preferred embodiments. To the contrary, the invention includes numerous alternatives, modifications and equivalents as will become apparent from consideration of the following detailed description and accompanying drawings.

[0019] 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 invention, 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”.

[0020] The term “a cathode active material”, also known as “a positive electrode active material” as used herein, and in the claims, is defined as a material which is electrochemically active in a positive electrode or cathode. By active material, it must be understood to be a material capable to capture and release Li ions when subjected to a voltage change over a predetermined period of time.

[0021] In the framework of the present invention “essentially Co free” means those that if Co is present it is present at such a low level that it does not materially affect the basic and novel characteristic of the present invention.

[0022] In the framework of the present invention, 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”.

[0023] In the context of the present disclosure, primary particles may be distinguished from each other in a SEM image by observing grain boundaries between the primary particles. The term “grain boundary” is defined as the interface between two primary particles, preferably wherein the atomic planes of the two primary particles are aligned to different orientations and meet as a crystalline discontinuity.

[0024] In the framework of the present invention, a molar ratio of an element A relative to M is the ratio (mol / mol) of the amount in mols of element A to the total amount of mols of all elements comprised in M. Thus molar ratios x, y, and z relative to M are the ratios of the molar amounts of Ni, Mn, and Mo respectively to the total of the molar amounts of all elements comprised in M.

[0025] "About" as used herein referring 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.

[0026] In a first aspect, the object of the invention is achieved by providing a cathode active material for rechargeable batteries comprising Li, M and 0, wherein M comprises: a. Ni in a molar ratio x, wherein 0.25 < x < 0.50 relative to M, b. Mn in a molar ratio y, wherein 0.50 < y < 0.80 relative to M, c. Mo in a molar ratio z, wherein 0.001 < z < 0.05 relative to M, wherein the molar ratio of Li to M (Li / M) is between 1 .00 and 1 .60; and wherein the content of Li, Ni, Mn and Mo is measured by ICP-AES, and x+y+z is 1 .00. M is a designation of the sum of Ni, Mn and Mo.

[0027] In one embodiment of the invention, this cathode active material has a composition according to a general formula (I) LiwNixiMnyiMoziO2, wherein: 1.00 < w < 1 .60; 0.25 < x1 < 0.50; 0.50 < y1 < 0.80; 0.001 < z1 < 0.05; wherein the content of Li, Ni, Mn and Mo is measured by ICP-AES, and x1 +y1 +z1 is 1.00.

[0028] A preferred embodiment is the cathode active material having a composition according to a general formula LiwNi0.38Mn0.6iMo0.01O2.

[0029] In a more preferred embodiment, the cathode active material has a composition with a general formula Li1.31 Ni0.38Mn0.6iMo0.01O2.

[0030] A preferred embodiment is the cathode active material according to the invention, wherein the molar ratio of Li to M (Li / M) is between 1.10 and 1.50, preferably between 1.15 and 1.44, more preferably between 1.20 and 1.32. The Li / M molar ratio may be at least 1.10, at least 1.15, at least 1 .20 or even at least 1 .25. The Li / M molar ratio may be at most 1 .50, at most 1 .45, at most 1 .40 or even at most 1 .35. In particular, the Li / M ratio may be 1 .36, 1 .33, 1 .32, 1.31 , 1 .29, 1 .285 or 1 .27; most preferably Li / M ratio is 1 .27 or 1 .31 .

[0031] In another preferred embodiment of the cathode active material according to the invention, the molar ratio of Mo z is in the range of 0.0025 < z < 0.05, preferably in the range of 0.005 < z < 0.01 .

[0032] Advantageously, z is at least 0.002, z is at least 0.003, z is at least 0.004, or even z is at least 0.002.

[0033] Advantageously z is at most 0.04, z is at most 0.03, z is at most 0.02, or even z is at most 0.01 .

[0034] In particular, the molar ratio of Mo z is about 0.0025, about 0.003, about 0.004, about 0.005, about 0.008, about 0.01 .

[0035] In another preferred embodiment of the cathode active material according to the invention, the molar ratio of Mo z1 is in the range of 0.0025 < z1 < 0.05, preferably in the range of 0.005 < z1 < 0.01 .

[0036] Advantageously, z1 is at least 0.002, z1 is at least 0.003, z1 is at least 0.004, or even z1 is at least 0.002.

[0037] Advantageously z1 is at most 0.04, z1 is at most 0.03, z1 is at most 0.02, or even z1 is at most 0.01 .

[0038] In particular, the molar ratio of Mo z1 is about 0.0025, about 0.003, about 0.004, about 0.005, about 0.008, about 0.01 .

[0039] In another preferred embodiment of the cathode active material according to the invention, the molar ratio of Ni x is in the range of 0.25 < x < 0.45, preferably in the range of 0.35 < x < 0.40, more preferably x is about 0.38. Cathode active materials that are richer in Ni, unless further modified, may show an intrinsic unstable behavior, including surf icial / interfacial issues, fatigue, inter / intragranular cracking, parasitic side reactions and thermal runway, causes severe capacity and voltage fading, deprived rate capability, and safety concerns during the charge / discharge process.

[0040] Advantageously x is at least 0.25, x is at least 0.30, or even x is at least 0.35.

[0041] Advantageously x is at most 0.45, or even x is at most 0.40.

[0042] In another preferred embodiment of the cathode active material according to the invention, the molar ratio of Ni x1 is in the range of 0.25 < x1 < 0.45, preferably in the range of 0.35 < x1 < 0.40, more preferably x1 is about 0.38.

[0043] Advantageously x1 is at least 0.25, x1 is at least 0.30, or even x1 is at least 0.35.

[0044] Advantageously x1 is at most 0.45, or even x1 is at most 0.40.

[0045] In another preferred embodiment of the cathode active material according to the invention, the molar ratio of Mn y is in the range of 0.50 < y < 0.70, preferably in the range of 0.55 < y or y1 < 0.65, more preferably y is about 0.61 .

[0046] Advantageously y is at least 0.50, or y is at least 0.55.

[0047] Advantageously y is at most 0.70, y is at most 0.65, or even y is at most 0.61

[0048] In another preferred embodiment of the cathode active material according to the invention, the molar ratio of Mn y1 is in the range of 0.50 < y1 < 0.70, preferably in the range of 0.55 < y1 < 0.65, more preferably y1 is about 0.61 .

[0049] Advantageously y1 is at least 0.50, or y1 is at least 0.55.

[0050] Advantageously y1 is at most 0.70, y1 is at most 0.65, or even y1 is at most 0.61

[0051] In another preferred embodiment of the cathode active material according to the invention, the molar ratio of Li w is in the range of 1 .1 < w < 1 .40, preferably in the range of 1 .15 < w < 1 .35, more preferably in the range of 1 .2 < w < 1 .32.

[0052] As appreciated by the skilled person the amount of x, y, z, x1 , y1 , z1 and w are measured by Inductively coupled plasma atomic emission spectrometry (ICP-AES), in particular the amounts of Li, Ni, Mn and Mo. For example, but not limited to this invention, a PerkinElmer NexION 2000 ICP mass spectrometer can be used for ICP- AES measurements.

[0053] In a preferred embodiment, the cathode active material comprises polycrystalline particles, which are secondary particles consisting of a plurality of primary particles,. The secondary particles may in particular consist of more than 20 primary particles. The number of primary particles constituting a secondary particle may be determined by counting the primary particles observed in a Scanning Electron Microscope (SEM) image at a magnification of 2000 from a top view, where the whole shape of the particle is taken Mo may be found in the grain boundaries as supported by the TEM images.

[0054] In another preferred embodiment, the cathode active material has a specific surface area (SSA) in the range of 0.9 to 2.0 m2 / g determined by BET analysis.

[0055] In a further object, the present invention provides a process for manufacturing said cathode active material through a solid-state synthesis route using a hydroxide precursor.

[0056] In another aspect, present invention relates to a process for manufacturing a cathode active material, comprising the following steps:Step 1 ) providing a nickel-manganese hydroxide precursor;Step 2) mixing the nickel-manganese hydroxide precursor with a molybdenum source, and a lithium source so as to obtain a mixture; andStep 3) heating the mixture at a temperature in a range of 800 to 1100 °C to afford the cathode active material, preferably heating at a temperature in a range of 925 to 975 °C.

[0057] In one embodiment, the precursor used in the Step 1 ) of the process is a nickelmanganese hydroxide precursor, or a compound comprising a nickel-manganese hydroxide precursor. In a particular embodiment, the nickel-manganese hydroxide precursor is Nix”Mny”(OH)2, wherein: a. 0.25 < x” < 0.50, preferably 0.25 < x” < 0.45, more preferably 0.35 < x” < 0.40, most preferably x” is 0.38; b. 0.50 < y” < 0.80, preferably 0.50 < y” < 0.70, more preferably 0.55 < y” < 0.65, most preferably y” is 0.62; and wherein the content of Ni and Mn is measured by ICP-AES, and x”+y” is 1.00.

[0058] In a preferred embodiment, the precursor is Nio.38Mno.62(OH)2. However, any other suitable nickel-manganese hydroxide precursor, or a compound comprising a suitable nickel-manganese hydroxide precursor would be a suitable modification of this process.

[0059] In an embodiment of Step 2) of the method of the present invention the nickel- manganese hydroxide precursor and molybdenum source, are added in proportions so as to obtain a mixture wherein the molar ratio of Mo to the sum of Ni and Mn is at least 0.01 mol%, at least 0.15 mol%, at least 0.20 mol% or even at least 0.25 mol%.

[0060] In an embodiment of Step 2) of the method of the present invention the nickel- manganese hydroxide precursor and molybdenum source, are added in proportions so as to obtain a mixture wherein the molar ratio of Mo to the sum of Ni and Mn is less than 5 mol%, or at most 3.0 mol%, or at most 2.0 mol%, or at most 1 .5 mol% at most 1 .0 mol%.

[0061] In one embodiment, the molybdenum source used in Step 2) is MoOs. However, any other suitable molybdenum source, or a compound comprising a suitable molybdenum source would be a suitable modification of this process. In a particularembodiment, MoOs is mixed with the nickel-manganese hydroxide precursor in a Mo content between 0.1 mol% to 10 mol% relative to nickel-manganese hydroxide precursor (Mo / (Ni+Mn)). In a more particular embodiment, MoOs is mixed in a content between 0.5 mol% to less than 5 mol% or 0.25 mol% to less than 5 mol% relative to nickel-manganese hydroxide precursor. In an even more particular embodiment, MoOs is mixed in a content between 0.25 mol% to 1 mol% relative to nickel-manganese hydroxide precursor.

[0062] In one embodiment, the lithium source used in Step 2) of the process is LiOH, Li2COs or a combination thereof. In a particular embodiment, the lithium source is Li2CO3. In a particular embodiment, Li2COs is mixed with the nickel-manganese hydroxide precursor in a content between 100 mol% to 160 mol% relative to nickel- manganese hydroxide precursor (Li / (Ni+Mn)). In a more particular embodiment, Li in the Li2COs is mixed in a content between 120 mol% to 140 mol% relative to nickel- manganese hydroxide precursor.

[0063] In one embodiment, the temperature of Step 3) used for heating the mixture is between 925 and 975 °C. In a more particular embodiment, the temperature is about 925, about 950 or about 975 °C.

[0064] In a further object, the present invention provides a battery comprising said cathode active material, in particular the cathode active material according to the first aspect of the invention.

[0065] Description of testing methods

[0066] Table 1 : list of equipment used in the synthesis and analysis

[0067] BET - The specific surface area of the cathode active material is measured with the Brunauer-Emmett-Teller (BET) method by using a Micromeritics Tristar II 3020. A powder sample is heated at 150 °C under nitrogen 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 77K. By obtaining the nitrogen isothermal absorption / desorption curve, the total specific surface area of the sample in m2 / g is derived.

[0068] ICP - The inductively coupled plasma (ICP) method is used to quantify elements by using an Agilent ICP 5110. 1 g of powder sample is dissolved in 50 mL high purity 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 ICP measurement.

[0069] Coin cell preparation - For the preparation of a cathode, a slurry that contains a cathode active material powder, conductor (Super P, Timcal), binder (KF#9700, Kureha) with a formulation of 83:8.0:8.0 by weight in a solvent (NMP, Mitsubishi) is prepared by a high-speed homogenizer. The homogenized slurry is spread on one side of an aluminum foil using a doctor blade coater with a 230 pm gap. The slurry coated foil is dried in an oven at 120 °C and then pressed using a calendaring tool. Then it is dried again in a vacuum oven to completely remove the remaining solvent in the electrode film. A coin cell is assembled in an argon-filled glovebox. A separator (Celgard 2320) is located between a cathode and a piece of lithium foil used as an anode. 1 M LiPFe in EC / DMC (3:7 in volume) is used as electrolyte and is dropped between separator and electrodes. Then, the coin cell is completely sealed to prevent leakage of the electrolyte.

[0070] DQ1 , DQ8 and Qirr % - The discharge capacity (DQ) and irreversible capacity (Qirr) tests were performed using coin cells prepared according to the method described above.

[0071] The discharge capacity of the first cycle (DQ1 ) was measured in the 4.8-2.0 V range with a rate of 0.05C at 25 °C, wherein the current of 1 C in this application is defined by using a capacity value of 160 mAh / g. The discharge capacity of the 8thcycle (DQ8) was measured in the 4.6-2.0 V range with a rate of 0.1 C at 25 °C.

[0072] The irreversible capacity (Qirr) is defined according to the following formula:Qirr (in %) = {(CQ1 - DQ1 ) / CQ1 } x 100, wherein DQ1 is the discharge capacity of the first cycle, and CQ1 is the charge capacity of the first cycle.

[0073] TEM - The electron microscopic images were measured with the Scanning Transmission Electron Microscopy (STEM) using High Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF-STEM), and Energy Dispersive X-Ray Spectroscopy (EDS) on an aberration-corrected FEI Titan transmission electron microscope at 300 kV, using a Super X detector. The sample was coated with Carbon before preparing the Focus Ion Beam (FIB) lamella. Then, the FIB lamella was prepared on a Cu Omniprobe TEM grid using a Thermo Fisher Helios FIB-SEM. The final thinning of the sample was done using 2kV. Before the TEM measurement, the sample was plasma cleaned 3 times in an argon plasma for 10 seconds at a power of 30 %.

[0074] Examples according to the invention and comparative examples - The invention will be described below in greater detail with reference to examples, but the invention is not limited in any way by these examples, as long as it does not exceed the scope and spirit of the present invention.

[0075] Example 1 — Lii.3i Nio.38Mno.6i8Moo.oo302 a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 0.20 g of MoOs (0.25 mol%) and 54.43 g of Li2COs (1 .33 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the mixture were transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows atemperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 925 °C at a heating rate of 1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of 5 °C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0076] Example 2 - Lii.3i Nio.38Mno.6i5Moo.oo502 a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 0.41 g of MoOs (0.50 mol%) and 54.40 g of Li2COs (1.33 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the mixture were transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 925 °C at a heating rate of 1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of 5 °C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0077] Example 3 — Li1.31 Ni0.38Mn0.6i0Mo0.01O2 a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 0.83 g of MoOs (1 .0 mol%) and 54.50 g of Li2COs (1 .33 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the mixture were transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 925 °C at a heating rate of 1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of 5°C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0078] Example 4 — Lii.27Nio.38Mno.6i7Moo.oo302 a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 0.21 g of MoOs (0.25 mol%) and 52.55 g of Li2COs (1 .29 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours.b. 25 grams of the blended mixture were transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 925 °C at a heating rate of1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate 5°C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0079] Example 5 - Lii.27Nio.38Mno.6i5Moo.oo502 a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 0.40 g of MoOs (0.50 mol%) and 52.58 g of Li2COs (1.29 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the blended mixture were transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 925 °C at a heating rate of1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of 5°C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0080] Example 6 — Li1.27Ni0.38Mn0.6i0Mo0.01 O2 a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 0.82 g of MoOs (1 .0 mol%) and 52.60 g of Li2COs (1 .29 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the blended mixture were transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 925 °C at a heating rate of1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of 5°C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0081] Example 7 - Li1.30Ni0.38Mn0.6i0Mo0.01 O2a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 0.80 g of MoOs (1 .0 mol%) and 54.40 g of U2CO3 (1 .33 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the blended mixture were transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 950 °C at a heating rate of1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of 5°C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0082] Comparative example 1 - Lii.3i Nio.38Mno.62o02 a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 53.20 g of Li2COs (1.33 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the mixture were transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 925 °C at a heating rate of 1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of 5 °C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0083] Comparative example 2 - Lii.27Nio.38Mno.62o02 a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 52.58 g of Li2COs (1.29 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the mixture transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 925 °C at a heating rate of 1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of 5 °C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0084] Comparative example 3 - Lii.3oNio.38Mno.62o02 a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 54.43 g of Li2COs (1.33 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the mixture were transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 950 °C at a heating rate of 1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of 5 °C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0085] Comparative example 4 - Li1.26Ni0.35Mn0.560Co0.09O2 a. In a dry room, 51 grams of Nio.35Mno.56Coo.o9(OH)2 precursor (1 .0 eq.) were mixed with and 51 .56 g of Li2COs (1 .26 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the mixture were transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 875 °C at a heating rate of 1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of 5 °C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0086] Comparative Example 5 - Li1.31 Ni0.38Mn0.6i5Mo0.05O2 a. In a dry room, 50 grams of Nio.38Mno.62(OH)2 precursor (1 .0 eq.) were mixed with 4.11 g of MoOs (5.0 mol%) and 54.40 g of Li2COs (1 .33 eq.) using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours. b. 25 grams of the mixture transferred to an alumina crucible which is placed in a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at a heating rate of 5 °C / min then heating to 925 °C at a heating rate of 1 .5 °C / min. That temperature was held for 10 hours before cooling down at a cooling rate of5°C / min. The crucible was then transferred from the furnace into a dry room and used for analysis.

[0087] Table 2 summarizes the chemical composition, specific surface area (SSA) values and electrochemical properties for each example and each comparative example.

[0088] Table 2

[0089] The LMR compounds comprising Mo have shown an improved capacity (DQ1 and / or DQ8 in Table I) and / or an improved irreversible capacity (Qirr% in Table I) when compared with the corresponding Mo-free compositions (see comparative examples in Table I). This technical effect can be observed in compounds comprising a low concentration of Mo (i.e. 2.5 mol% of Mo), see Ex 1 from Table I, wherein the DQ8 capacity is 232.5 mAh / g versus 217.7 mAh / g of the corresponding Mo-free composition (Com Ex 1 ). Moreover, the technical effect is maintained within a long range of concentrations of Mo: from 0.25, but not limited to 1 .00 mol%of Mo, see Ex 1 -3 from Table I.

[0090] Moreover, the technical effect was also observed in compounds with different Li / M ratios, such as but not limited to 1 .27, 1 .30, and 1 .31 , see Ex 1 , Ex 4 and Ex 7 from Table I.

[0091] Compounds comprising Mo according to this invention have also shown an improved, that is lower, irreversible capacity as can be shown in Table I, see Ex 1-3 with 13.6-14.9% versus 17.4% of Com Ex 1.

[0092] Co-free LMR material comprising Molybdenum provides an improved capacity and lowered irreversible capacity. Therefore, in a preferred embodiment of the invention, the LMR materials are Cobalt-free materials.

[0093] Figures 1 and 2 show the a part of a cross-section of secondary particles of Example 3 and the distribution of Mo in Example 3 which can be observed as white spots in fig 1 and 2. As it can be observed, Mo enriches the grain boundaries between primary particles .

[0094] Figure 3 shows the another part of a cross section of a secondary particle ofExample 3 and the distribution of Mo in Example 3. As it can be observed, Mo enriches the center of the secondary particle between the primary particles.

Claims

CLAIMS

1. A cathode active material for rechargeable batteries comprising Li, M and 0, wherein M comprises: a. Ni in a molar ratio x, wherein 0.25 < x < 0.50 relative to M, b. Mn in a molar ratio y, wherein 0.50 < y < 0.80 relative to M, and c. Mo in a molar ratio z, wherein 0.001 < z < 0.05 relative to M, wherein the molar ratio of Li to M (Li / M) is between 1 .00 and 1 .60; and wherein the content of Li, Ni, Mn and Mo is measured by ICP-AES, and x+y+z is 1 .00.

2. The cathode active material according to claim 1 , having a composition according to a general formula (I) LiwNixiMnyiMoziO2, wherein: a. 1.00 < w < 1.60; b. 0.25 < x1 < 0.50; c. 0.50 < y1 < 0.80; d. 0.001 < z1 < 0.05; and wherein the content of Li, Ni, Mn and Mo is measured by ICP-AES, and x1 +y1 +z1 is 1 .00.

3. The cathode active material according to claim 1 , wherein 0.0025 < z <0.05.

4. The cathode active material according to any of the claims 1 or 3, wherein 0.25 < x < 0.45.

5. The cathode active material according to any of the claims 1 or 3 to 4, wherein 0.50 < y < 0.70.

6. The cathode active material according to any of the claims 1 or 3 to 5, wherein a. z is at least 0.002, z is at least 0.003, z is at least 0.004, or even z is at least 0.002 and / or b. z is at most 0.04, z is at most 0.03, z is at most 0.02, or even z is at most

7. The cathode active material according to any of the claim 2, wherein 0.0025 < z1 <0.05.

8. The cathode active material according to any of the claims 2 or 7, wherein 0.25 < x1 < 0.45.

9. The cathode active material according to any of the claims 2 or 7 to 8, wherein 0.50 < y1 < 0.70.

10. The cathode active material according to any of the claims 2 or 7 to 9, wherein 1.1 < w < 1.40.

11. The cathode active material according to any one preceding claim, wherein the molar ratio of Li to M (Li / M) is between 1.10 and 1.50, preferably between 1.15 and 1.44, more preferably between 1.20 and 1.32.

12. A process for manufacturing a cathode active material according to any of the claims 1 to 11 , comprising the following steps:Step 1 ) providing a nickel-manganese hydroxide precursor;Step 2) mixing the nickel-manganese hydroxide precursor with a molybdenum source, and a lithium source so as to obtain a mixture; andStep 3) heating the mixture at a temperature in a range of 800 to 1100 °C to afford the cathode active material, preferably heating at a temperature in a range of 925 to 975 °C.

13. The process according to claim 12, wherein in Step 2) the molybdenum source is MoOs, wherein MoOs is mixed with the nickel-manganese hydroxide precursor in a content of 0.25 to less than 5 mol% relative to the nickel-manganese hydroxide precursor,.

14. The process according to claim 12 or 13, wherein in Step 2) the lithium source in a content of 120 to 140 mol% of lithium relative to the nickel- manganese hydroxide precursor is mixed with the nickel-manganese hydroxide precursor.

15. A battery comprising a cathode active material according to any of the claims 1 to 11 .

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