Lithium-manganese-based oxide as a cathode active material for lithium-ion rechargeable batteries

Abstract

A cathode active material for rechargeable batteries comprising lithium, M1, and oxygen, wherein M1 comprises: - Ni in a content x1, wherein 0.0 < x1 < 45.0 at%, relative to M1; - Mn in a content y1, wherein 50.0 < y1 < 98.0 at%, relative to M1; - Co in a content z1, wherein 0.0 < z1< 15.0 at%, relative to M1; - Na in a content w1, wherein 0.0 < w1 < 2.0 at%, relative to M1; - S in a content molar ratio ql, wherein 0.0 < q1 < 5.0 at%, relative to M1; - D1 in a content molar ratio dl, wherein 0.0 < d2 < 2.0 at%, relative to M1, wherein D1 is an element different from Li, Ni, Mn, Co, Na, S and O; wherein the content of Ni, Mn, Co, Na, S and D1 is measured by ICP-OES, and x1+y1+z1+w1+q1+d1 is 100.0 at%, and wherein the cathode active material has a BET value of at least 1.0 m2 / g.

Description

[0001] LITHIUM-MANGANESE-BASED OXIDE AS A CATHODE ACTIVE MATERIAL FOR LITHIUM-ION RECHARGEABLE BATTERIES

[0002] TECHNICAL FIELD d

[0003] The present invention relates to a lithium manganese-based oxide cathode active material for lithium-ion secondary batteries (LIBs) suitable for electric vehicle (EV) and hybrid electric vehicle (HEV) applications, a method of manufacturing said cathode active material, a battery comprising said cathode active material and the use of said battery.

[0004] BACKGROUND

[0005] Secondary batteries have become increasingly vital in modern energy storage systems, powering a wide array of devices ranging from portable electronics to electric vehicles. As the development of small and lightweight electronic products, electronic devices, communication devices and the like have advanced rapidly and a need for electric vehicles has widely emerged with respect to environmental issues, there is a demand for improvement of performance of secondary batteries used as power sources for these products. With the growing demand for high-capacity, long- lasting, and stable rechargeable batteries, there is a critical need for the development of advanced cathode materials that can meet the stringent requirements of various battery applications.

[0006] Lithium- and manganese-rich oxides are appealing in terms of safety and energy density. However, these lithium- and manganese-rich oxides must be charged above 4.5 V to reach high discharge capacities of around 250 mAh / g. This high operating potential (>4.5 V) poses serious problems for the long-term stability of these cathodes due to their unfavorable reactions with the electrolyte and dissolution of transition metals occurring at the electrode-electrolyte interface. As a result the cycle performance of the cathode active material is reduced.

[0007] Therefore, there is a need to mitigate the reaction between these cathodes and electrolytes by modifying these cathodes thereby further increasing the cycle life of the cathode active materials. The electrochemical properties, stability, and specific surface area of the cathode active material are crucial factors that directly influence the overall performance and longevity of secondary batteries. It is an object of the present invention to provide a cathode active material having one or more improved properties, such as an increased cycle performance.

[0008] It is a further object of the present invention to provide a method for manufacturing the cathode active material.

[0009] It is a further object of the present invention to provide a battery comprising the cathode active material.

[0010] It is a further object of the present invention to provide a use of the battery.

[0011] SUMMARY OF THE INVENTION

[0012] This object of the present invention is achieved by providing a cathode active material for rechargeable batteries comprising lithium, Ml, and oxygen, wherein Ml comprises:

[0013] - Ni in a content xl, wherein 0.0 < xl < 45.0 at%, relative to Ml;

[0014] - Mn in a content yl, wherein 50.0 < yl < 98.0 at%, relative to Ml;

[0015] - Co in a content zl, wherein 0.0 < zl < 15.0 at%, relative to Ml;

[0016] - Na in a content wl, wherein 0.0 < wl < 2.0 at%, relative to Ml;

[0017] - S in a content molar ratio ql, wherein 0.0 < ql < 5.0 at%, relative to Ml;

[0018] - DI in a content molar ratio dl, wherein 0.0 < dl < 2.0 at%, relative to Ml, wherein Dl is an element different from Li, Ni, Mn, Co, Na and S; wherein the content of Ni, Mn, Co, Na, S and Dl is measured by ICP-OES, and xl+yl+zH-wH-qH-dl is 100.0 at%, and wherein the cathode active material has a BET value of at least 1.0 m2 / g.

[0019] A further aspect of the present invention provides a method for manufacturing the cathode active material for rechargeable batteries, comprising the following steps:

[0020] Step 1) providing a nickel-manganese carbonate precursor;

[0021] Step 2) optionally heating the nickel-manganese carbonate precursor at a temperature in a range of 300 to 500 °C;

[0022] Step 3) mixing the nickel-manganese carbonate precursor or the heated nickel- manganese carbonate precursor with: a sulfate salt in a content of 1 to 5 mol% of sulfur present in the sulfate salt relative to the nickel-manganese carbonate precursor or the heated nickelmanganese carbonate precursor, wherein the sulfate salt is selected from the group consisting of MgSC , Al2(SO4)3 and CoSC ; or U2SO4; and a lithium source in a content of 100 to 150 mol% of lithium present in the second lithium source relative to the second nickel-manganese carbonate precursor or the heated nickel-manganese carbonate precursor; wherein the second lithium source is selected from U2CO3, LiOH and combinations thereof, Step 4) heating the mixture from Step 3) at a temperature in a range of 800 to 1000 °C to afford the cathode active material;

[0023] Step 5) optionally washing the cathode active material with water;

[0024] Step 6) optionally drying the washed cathode active material at a temperature in a range of 80 to 120 °C; and

[0025] Step 7) optionally heating the washed or dried cathode active material at a temperature in a range of 600 to 800 °C to afford the heated cathode active material.

[0026] A further aspect of the present invention provides a battery comprising the cathode active material.

[0027] A further aspect of the present invention provides a use of the battery.

[0028] DETAILED DESCRIPTION

[0029] 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.

[0030] 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".

[0031] A cathode active material is defined as a material which is electrochemically active in a positive electrode. By active material, it must be understood a material capable of capturing and releasing Li ions when subjected to a voltage change over a predetermined period of time.

[0032] In the framework of the present invention, mol% signifies molar percentage. The mol% or "mol 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 mol% is equivalent to at% or atomic percent.

[0033] In the following detailed description, preferred embodiments are described to enable the practice of the invention. Although the invention is described with reference to these specific preferred embodiments, it will be understood that the following examples are intended to further clarify the present invention and are nowhere intended to limit the scope of the present invention. The invention includes numerous alternatives, modifications and equivalents that are apparent from consideration of the following detailed description.

[0034] Cathode active material

[0035] In a first aspect, the present invention provides a cathode active material for lithium- ion rechargeable batteries, comprising lithium, Ml, and oxygen, wherein Ml comprises:

[0036] - Ni in a content xl, wherein 0.0 < xl < 45.0 at%, relative to Ml;

[0037] - Mn in a content yl, wherein 50.0 < yl < 98.0 at%, relative to Ml;

[0038] - Co in a content zl, wherein 0.0 < zl < 15.0 at%, relative to Ml;

[0039] - Na in a content wl, wherein 0.0 < wl < 2.0 at%, relative to Ml;

[0040] - S in a content molar ratio ql, wherein 0.0 < ql < 5.0 at%, relative to Ml; - DI in a content molar ratio dl, wherein 0.0 < dl < 2.0 at%, relative to Ml, wherein DI is an element different from Li, Ni, Mn, Co, Na and S; wherein the content of Ni, Mn, Co, Na, S and Dl is measured by ICP-OES, and xl+yl+zl+wl+qH-dl is 100.0 at%, and wherein the cathode active material has a BET value of at least 1.0 m2 / g.

[0041] In an embodiment the cathode active material for lithium-ion rechargeable batteries, comprises lithium, Ml, and oxygen, wherein Ml comprises:

[0042] - Ni in a content xl, wherein 10.0 < xl < 45.0 at%, relative to Ml; preferably 20.0

[0043] < xl < 40.0 at%, more preferably 35.0 < xl < 42.0 at%, relative to Ml;

[0044] - Mn in a content yl, wherein 55.0 < yl < 90.0 at%, relative to Ml; preferably 58.0

[0045] < yl < 80.0 at%, more preferably 58.0 < yl < 70.0 at%, relative to Ml;

[0046] - Co in a content zl, wherein 0.0 < zl < 10.0 at%, relative to Ml; preferably 0.0 < zl < 5.0 at%, more preferably zl is about 0.0 at%, relative to Ml.

[0047] Preferably, the Na content wl is more than 0.01 at% relative to Ml, preferably more than 0.02 at% relative to Ml, preferably more than 0.03 at% relative to Ml, more preferably more than 0.04 at% relative to Ml. Preferably, the Na content wl is less than 1.0 at% relative to Ml, preferably less than 0.9 at% relative to Ml, preferably less than 0.5 at% relative to Ml, more preferably less than 0.1 at% relative to Ml. Preferably, the Na content wl is in the range of 0.01 < wl < 1.0 at% relative to Ml, preferably, in the range of 0.02 < wl < 0.9 at% relative to Ml, preferably, in the range of 0.02 < wl < 0.9 at% relative to Ml, preferably, in the range of 0.03 < wl

[0048] < 0.9 at% relative to Ml, preferably, in the range of 0.03 < wl < 0.5 at% relative to Ml, more preferably, in the range of 0.04 < wl < 0.1 at% relative to Ml.

[0049] Preferably, the S content ql is more than 0.01 at% relative to Ml, preferably more than 0.02 at% relative to Ml, preferably more than 0.03 at% relative to Ml, preferably more than 0.04 at% relative to Ml, preferably more than 0.05 at% relative to Ml, more preferably more than 0.09 at% relative to Ml. Preferably, the S content ql is less than 3.5 at% relative to Ml, preferably less than 2.5 at% relative to Ml, preferably less than 1.1 at% relative to Ml, preferably less than 1.0 at% relative to Ml, preferably less than 0.5 at% relative to Ml, more preferably less than 0.2 at% relative to Ml. Preferably, the S content ql is in the range of 0.01 < wl < 3.5 at% relative to Ml, preferably, in the range of 0.02 < wl < 2.5 at% relative to Ml, preferably, in the range of 0.03 < wl < 1.1 at% relative to Ml, preferably, in the range of 0.04 < wl < 1.0 at% relative to Ml, preferably, in the range of 0.05 < wl < 0.5 at% relative to Ml, more preferably, in the range of 0.09 < wl < 0.2 at% relative to Ml.

[0050] As is known to the skilled person, the positive electrode active material of the invention can comprise impurities or be doped or coated resulting in an overall positive electrode active material comprising one or more elements other than Li, Ni, Mn, Co, S, Na and O, which is reflected in the parameter "DI" used herein. A preferred embodiment is the positive electrode active material according to the invention comprising DI, wherein DI is at least one element selected from the group consisting of Al, Ti, Ba, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sr, V, W, Y, Zn, and Zr; preferably Al, Ti, Cr, Nb, Si, Y, Zr and W; more preferably Al, Ti, Nb, Zr and W.

[0051] A preferred embodiment is the positive electrode active material according to the invention, wherein DI is in q content dl > 0.0 at%, preferably dl > 0.25 at%, more preferably dl > 0.5 at%. In a preferred embodiment the content dl < 1.75 at%, preferably dl < 1.5 at%, more preferably dl < 1.25 at%. In a preferred embodiment the content is 0.0 at% < dl < 1.75 at%, preferably 0.25 at% < dl < 1.5 at%, more preferably 0.5 at% < dl < 1.25 at%.

[0052] In a preferred embodiment the molar ratio of Li to Ml (mol / mol) is more than 0.9, preferably more than 1.0, more preferably more than 1.1. In a preferred embodiment the molar ratio of Li to Ml (mol / mol) is less than 1.6, preferably less than 1.5, more preferably less than 1.4. In a preferred embodiment the molar ratio of Li to Ml (mol / mol) is between 0.9 and 1.6, preferably between 1.0 and 1.5, more preferably between 1.1 and 1.4.

[0053] In a preferred embodiment the cathode active material has a BET value of more than 0.5 m2 / g, preferably more than 1.0 m2 / g, more preferably more than 1.2 m2 / g. In a preferred embodiment the cathode active material has a BET value of less than 8 m2 / g, preferably less than 6.5 m2 / g, more preferably less than 5.1 m2 / g. In a preferred embodiment the cathode active material has a BET between 0.5 and 8 m2 / g, preferably a BET between 1.0 and 8 m2 / g, more preferably a BET between 1.2 and 8 m2 / g. In a preferred embodiment the cathode active material has a BET between 1.2 and 6.5 m2 / g, more preferably a BET between 1.2 and 5.1 m2 / g. In certain preferred embodiments the cathode active material has a BET between 4.0 and 5.0 m2 / g. In other certain preferred embodiments the cathode active material has a BET between 2.0 and 4.0 m2 / g, preferably between 2.5 and 3 m2 / g.

[0054] In an embodiment the cathode active material has a formula Liw2Nia2Mnb2COc2Nad2Se2D2f2O2, wherein :

[0055] 0.90 < w2 < 1.60,

[0056] 0.0 < a2 < 0.45,

[0057] 0.50 < b2 < 0.98,

[0058] 0.0 < c2 < 0.15,

[0059] 0.0 < d2 < 0.02,

[0060] 0.0 < e2 < 0.05,

[0061] 0.0 < f2 < 0.02, wherein D2 is an element different from Li, Ni, Mn, Co, Na and S, wherein the content of Li, Ni, Co, Mn, Na, S and D2 is measured by ICP-OES and a2+b2+c2+d2+e2+f2 = 1.00.

[0062] In a preferred embodiment the content of Li, w2 is more than 0.8, preferably more than 0.9, more preferably more than 1.0. In a preferred embodiment the content of Li, w2 is less than 1.5, preferably less than 1.4, more preferably less than 1.3. In a preferred embodiment the content of Li, w2 is in the range of 0.8 < w2 < 1.5, preferably, in the range of 0.9 < w2 < 1.4, more preferably in the range of 1.0 < w2 < 1.3.

[0063] In a preferred embodiment the content of Ni, a2 is more than 0.20, preferably more than 0.35. In a preferred embodiment the content of Ni, a2 is less than 0.40. In a preferred embodiment the content of Ni, a2 is in the range of 0.20 < a2 < 0.45, preferably in the range of 0.35 < a2 < 0.40, more preferably a2 is about 0.40.

[0064] In a preferred embodiment the content of Mn, b2 is more than 0.55, preferably more than 0.58. In a preferred embodiment the content of Mn, b2 is less than 0.80, preferably less than 0.70. In a preferred embodiment the content of Mn, b2 is in the range of 0.55 < b2 < 0.78, preferably in the range of 0.58 < b2 < 0.70, more preferably b2 is about 0.60.

[0065] In a preferred embodiment the content of Co, c2 is in the range of 0.0 < c2 < 0.10, preferably 0.0 < c2 < 0.05, preferably c2 is about 0.0.

[0066] In a preferred embodiment the content of Na, d2 is more than 0.0002, preferably more than 0.0003, more preferably more than 0.0004. In a preferred embodiment the content of Na, d2 is less than 0.01, preferably less than 0.009, more preferably less than 0.001. In a preferred embodiment the content of Na, d2 is in the range of 0.0002 < d2 < 0.01, preferably, in the range of 0.0003 < d2 < 0.009, more preferably in the range of 0.0004 < d2 < 0.001.

[0067] In a preferred embodiment the content of S, e2 is more than 0.0004, preferably more than 0.0005, more preferably more than 0.0009. In a preferred embodiment the content of S, e2 is less than 0.01, preferably less than 0.005, more preferably less than 0.002. In a preferred embodiment the content of S, e2 is in the range of 0.0004 < e2 < 0.01, preferably, in the range of 0.0005 < e2 < 0.005, more preferably in the range of 0.0009 < e2 < 0.002.

[0068] As is known to the skilled person, the positive electrode active material of the invention can comprise impurities or be doped or coated resulting in an overall positive electrode active material comprising one or more elements other than Li, Ni, Mn, Co, S, Na and O, which is reflected in the parameter "DI" used herein. A preferred embodiment is the positive electrode active material according to the invention comprising DI, wherein DI is at least one element selected from the group consisting of Al, Ti, Ba, B, Ca, Ce Cr, Fe, Mg, Mo, Nb, Si, Sr, V, W, Y, Zn, and Zr; preferably Al, Ti, Cr, Nb, Si, Y, Zr and W; more preferably Al, Ti, Nb, Zr and W.

[0069] In a preferred embodiment the content of D2, f2 is in the range of 0.0 < f2 < 0.01, more preferably 0.0 < f2 < 0.005, preferably f2 is about 0.0. As appreciated by the skilled person the amount of Na, S, Li, Ni, Mn, Co, F, Al measured with Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). For example, but not limiting to the invention, an Agilent ICP 720-ES is used in the ICP-OES analysis. In the framework of the present invention, "atomic content" 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 mol% is equivalent to "molar percent" or "at%". For example, but not limiting to the invention, XPS analysis is carried out with a Thermo K-o+ spectrometer (Thermo Scientific).

[0070] Method for manufacturing

[0071] In a second aspect, the present invention is also inclusive of a method for manufacturing a cathode active material, comprising the steps of:

[0072] Step 1) providing a first nickel-manganese carbonate precursor;

[0073] Step 2) optionally heating the first nickel-manganese carbonate precursor at a temperature in a range of 300 to 500 °C, preferably 400 °C;

[0074] Step 3) mixing the first nickel-manganese carbonate precursor or the heated first nickel-manganese carbonate precursor with:

[0075] U2SO4 in a content of 1 to 5 mol% of sulfur present in the Li2SO4relative to the first nickel-manganese carbonate precursor or the heated first nickel- manganese carbonate precursor; and a first lithium source in a content of 100 to 150 mol% of lithium present in the first lithium source relative to the first nickel-manganese carbonate precursor or the heated first nickel-manganese carbonate precursor; wherein the first lithium source is selected from Li2CO3, LiOH and combinations thereof, preferably the lithium source is Li2CO3, Step 4) heating the mixture from Step 3) at a temperature in a range of 800 to 1000 °C to afford a mixture, preferably mixing and stirring at a temperature of 925 °C to prepare a heated material;

[0076] Step 5) washing the heated material with water;

[0077] Step 6) optionally drying the washed material at a temperature in a range of 80 to 120 °C, preferably at 100 °C; and

[0078] Step 7) heating the washed or dried material at a temperature in a range of 600 to 800 °C to afford the cathode active material, preferably heating the washed or dried material at 700 °C, wherein the nickel manganese carbonate precursor comprises M2, carbon and oxygen, wherein M2 comprises:

[0079] Ni in a content x3, wherein 0.0 < x3 < 45 at% relative to M2;

[0080] Mn in a content y3, wherein 50.0 < y3 < 98.0 at% relative to M2;

[0081] Co in a content z3, wherein 0.0 < z3 < 15.0 at%, relative to M2; and

[0082] D3 in a content d3, wherein 0.0 < d3 < 2.0 at% relative to M2, wherein D3 is an element different from Ni, Mn, carbon, and oxygen; wherein the content of Ni, Mn and D3 is measured by ICP-OES, and x3+y3+d3 = 100.0 at%.

[0083] In a preferred embodiment the content of Ni, x3 is more than 20 at%, preferably more than 35 at%. In a preferred embodiment the content of Ni, x3 is less than 40 at%. In a preferred embodiment the content of Ni, x3 is in the range of 20 < x3 < 45 at%, preferably in the range of 35 < x3 < 40 at%, more preferably x3 is about 40 at%.

[0084] In a preferred embodiment the content of Mn, y3 is more than 55 at%, preferably more than 58 at%. In a preferred embodiment the content of Mn, y3 is less than 80 at%, preferably less than 70 at%. In a preferred embodiment the content of Mn, y3 is in the range of 55 < y3 < 78 at%, preferably in the range of 58 < y3 < 70 at%, more preferably y3 is about 60 at%.

[0085] In a preferred embodiment the content of Co, z3 is in the range of 0.0 < z3 < 10 at%, preferably 0.0 < z3 < 5 at%, preferably z3 is about 0.0 at%.

[0086] In a preferred embodiment D3 is at least one element selected from the group consisting of Al, Ti, Ba, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sr, V, W, Y, Zn, and Zr; preferably Al, Ti, Cr, Nb, Si, Y, Zr and W; more preferably Al, Ti, Nb, Zr and W.

[0087] In a preferred embodiment the content of D3, d3 is more than 0.0 at%, preferably more than 0.25 at%, more preferably more than 0.5 at%. In a preferred embodiment the content d3 is less than 1.75 at%, preferably less than 1.5 at%, more preferably less than 1.25 at%. In a preferred embodiment the content d3 is in the range of 0.0 at% < d3 < 1.75 at%, preferably 0.25 at% < d3 < 1.5 at%, more preferably 0.5 at% < d3 < 1.25 at%. In a third aspect of the present invention is also inclusive of another method for manufacturing a cathode active material, comprising the steps of:

[0088] Step 1) providing a second nickel-manganese carbonate precursor;

[0089] Step 2) optionally heating the second nickel-manganese carbonate precursor at a temperature in a range of 300 to 500 °C, preferably 400 °C;

[0090] Step 3) mixing the second nickel-manganese carbonate precursor or the heated second nickel-manganese carbonate precursor with: a sulfate salt in a content of 1 to 5 mol% of sulfur present in the sulfate salt relative to the nickel-manganese carbonate precursor or the heated nickel- manganese carbonate precursor, wherein the sulfate salt is selected from the group consisting of MgSO4, AI2(SO4)3and CoSO4; and a second lithium source in a content of 100 to 150 mol% of lithium present in the second lithium source relative to the second nickel-manganese carbonate precursor or the heated nickel-manganese carbonate precursor; wherein the second lithium source is selected from Li2CO3, LiOH and combinations thereof, preferably the second lithium source is Li2CO3, Step 4) heating the mixture from Step 3) at a temperature in a range of 800 to 1000 °C to afford the cathode active material, preferably mixing and stirring at a temperature of 925 °C to prepare a cathode active material;

[0091] Step 5) optionally washing the cathode active material with water;

[0092] Step 6) optionally drying the washed cathode active material at a temperature in a range of 80 to 120 °C, preferably at 100 °C; and

[0093] Step 7) optionally heating the washed or dried cathode active material at a temperature in a range of 600 to 800 °C to afford the heated cathode active material, preferably heating the washed or dried mixture at 700 °C, wherein the second nickel manganese carbonate precursor comprises M3, carbon and oxygen, wherein M3 comprises:

[0094] Ni in a content x4, wherein 0.0 < x4 < 45 at% relative to M3;

[0095] Mn in a content y4, wherein 50.0 < y4 < 98.0 at% relative to M3;

[0096] Co in a content z3, wherein 0.0 < z4 < 15.0 at%, relative to M3; and

[0097] D4 in a content d4, wherein 0.0 < d4 < 2.0 at% relative to M3, wherein D4 is an element different from Ni, Mn, carbon, and oxygen; wherein the content of Ni, Mn and D4 is measured by ICP-OES, and x4+y4+d4 = 100.0 at%. A preferred embodiment of the method according to the third aspect of the invention includes step 5) of washing the cathode active material with water

[0098] In a preferred embodiment the content of Ni, x4 is more than 20 at%, preferably more than 35 at%. In a preferred embodiment the content of Ni, x4 is less than 40 at%. In a preferred embodiment the content of Ni, x4 is in the range of 20 < x4 < 45 at%, preferably in the range of 35 < x4 < 40 at%, more preferably x4 is about 40 at%.

[0099] In a preferred embodiment the content of Mn, y4 is more than 55 at%, preferably more than 58 at%. In a preferred embodiment the content of Mn, y4 is less than 80, preferably less than 70 at%. In a preferred embodiment the content of Mn, y4 is in the range of 55 < y4 < 78 at%, preferably in the range of 58 < y4 < 70 at%, more preferably y4 is about 60 at%.

[0100] In a preferred embodiment the content of Co, z4 is in the range of 0.0 < z4 < 10 at%, preferably 0.0 < z4 < 5 at%, preferably z3 is about 0.0 at%.

[0101] In a preferred embodiment D4 is at least one element selected from the group consisting of Al, Ti, Ba, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sr, V, W, Y, Zn, and Zr; preferably Al, Ti, Cr, Nb, Si, Y, Zr and W; more preferably Al, Ti, Nb, Zr and W.

[0102] In a preferred embodiment the content of D4, d4 is > 0.0 at%, preferably d4 > 0.25 at%, more preferably d4 > 0.5 at%. In a preferred embodiment the content d4 is < 1.75 at%, preferably d4 < 1.5 at%, more preferably d4 < 1.25 at%. In a preferred embodiment the content d4 is in the range of 0.0 at% < d4 < 1.75 at%, preferably 0.25 at% < d4 < 1.5 at%, more preferably 0.5 at% < d4 < 1.25 at%.

[0103] Batery

[0104] In a third aspect the present invention concerns a battery comprising the cathode active material according to the first aspect of the invention.

[0105] In a preferred embodiment the battery is a lithium-ion battery, preferably a lithium- ion rechargeable battery. Preferably the battery comprises a positive electrode comprising the cathode active material according to the first aspect of the invention, a negative electrode, an electrode, and a separator.

[0106] Use

[0107] In a fourth aspect the present invention concerns a use of the cathode active material according to the first aspect of the invention in a battery.

[0108] A preferred embodiment is the use of the cathode active material in a battery, preferably the battery according to the third aspect of the invention, to increase the efficiency of the battery.

[0109] In a fifth aspect the present invention concerns a use of the battery according to the third aspect of the invention in either one of a portable computer, a tablet, a mobile phone, an energy storage system (ESS), an electric vehicle (EV) or in a hybrid electric vehicle (HEV), preferably in an electric vehicle or in a hybrid electric vehicle.

[0110] Examples and comparative examples

[0111] A) Particle size distribution (PSD) analysis

[0112] Data about the particle size distribution (PSD) such as particle size at set percentile (DIO, D50, D99) and span are preferably obtained by a laser PSD measurement method. The PSD was measured using a Malvern Mastersizer 3000 with Hydro 3000MV wet dispersion accessory. Samples were first dispersed in an aqueous medium in preparation for measurement. In order to improve the dispersion of the powder in the aqueous medium, sufficient ultrasonic irradiation and stirring were applied, as well as an appropriate surfactant. Note that a narrow span (besides particle size homogeneity) is an indicator of a pronounced sphericity of a particle, the value of the span is used in the examples to measure sphericity.

[0113] B) Inductive Couple Plasma Optical Emission Spectrometry (ICP-OES) analysis

[0114] The inductively coupled plasma optical emission spectrometry (ICP-OES) method is used to quantify elements by using an Agillent ICP 5110. 1 gram of powder sample was dissolved in 50 mL high purity hydrochloric acid in an Erlenmeyer flask. The flask was covered by glass and heated on a hot plate for complete dissolution of the material. After being cooled to room temperature, the solution was moved to a 500 mL volumetric flask that was thoroughly cleaned and rinsed with distilled water. After filling the flask with the solution, the volumetric flask was filled with distilled water up to the 500 mL mark, followed by complete homogenization. 5 mL solution was 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 was filled with 10% hydrochloric acid up to the 50 mL mark and then homogenized. Finally, this 50 mL solution was used in the ICP measurement.

[0115] C) Surface area analysis (BET)

[0116] Gas adsorption was conducted using the Brunauer-Emmett-Teller (BET) theory to determine the specific surface area of the material. Samples were first pre-treated by weighing 1 gram into a suitable sized gas adsorption sample vial. The sample was then heated to 150 °C under nitrogen flow for 1 hour using a Micromeritics VacPrep 061 to move any adsorbed species. BET specific surface area was then measured using a Micromeritics TriStar 3020. "BET value" in the present invention stands for a specific surface area value measured by the BET analysis.

[0117] D) Discharge capacity and irreversible capacity analysis

[0118] The discharge capacity and irreversible capacity tests were performed using coin cells wherein the electrode consists of 96 wt% of the cathode active material according to this invention. The electrode loading of the cathode active material is about 6 mg / cm2.

[0119] 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 1C in the present invention is defined by using a capacity value of 160 mAh / g.

[0120] The irreversible capacity (Qirr) is defined according to the following formula:

[0121] 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.

[0122] Synthetic procedure to obtain a cathode active material according to the invention and comparative examples is further illustrated by the following (non-limitative) examples: Comparative example 1 (CEx 1)

[0123] Step 1) Initially, 400 grams of Nio.4oMno.6oC03precursor with bed depth of 20 mm were transferred to an alumina crucible and the alumina crucible was placed in a furnace with 10 b / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 400 °C at 5 °C / min and then, the temperature was held at 400 °C for 10 hours before cooling down at 5 °C / min. The alumina crucible with a heated precursor was then transferred from the furnace into a dry room.

[0124] Step 2) washing : 50 grams of the heated precursor were transferred into a 200 mL glass beaker with a stirring magnet. 50 grams of water were added into the glass beaker so as to prepare a slurry. The slurry was stirred for 10 minutes. Then, the slurry was filtered so as to prepare a first washed precursor. The same washing procedure was repeated to prepare a second washed precursor using the first washed precursor instead of the heated precursor..

[0125] Step 3) 25.0 grams of the second washed precursor were mixed with 11.6 grams of U2CO3 using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours to prepare a mixture. Later, 25 grams of the mixture were transferred to an alumina crucible. The alumina crucible was 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 5 °C / min then heating to 925 °C at 1.5 °C / min. That temperature was held for 10 hours before cooling down at 5 °C / min. The resulting material (CEx 1) was transferred from the furnace into a dry room.

[0126] Example 1 (Ex 1)

[0127] Step 1) 400 grams of Nio.4oMn0.6oC03precursor with bed depth of 20 mm were transferred to an alumina crucible and the alumina crucible was placed in a furnace with 10 b / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 400 °C at 5 °C / min and then, the temperature was held at 400 °C for 10 hours before cooling down at 5 °C / min. The alumina crucible with a heated precursor was then transferred from the furnace into a dry room.

[0128] Step 2) 25.0 grams of the heated precursor were mixed with 0.75 grams of Li2SO4and 11.6 grams of LkCCh using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours to prepare a mixture. Later, 25 grams of the mixture were transferred to an alumina crucible. The alumina crucible was placed in a furnace with 10 b / rnin dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at 5 °C / min then heating to 925 °C at 1.5 °C / min. That temperature was held for 10 hours before cooling down at 5 °C / min. A heated material was transferred from the furnace into a dry room.

[0129] Step 3) washing: 50 grams of the heated material were transferred into a 200 mL glass beaker with a stirring magnet. 50 grams of water were added into the glass beaker so as to prepare a slurry. The slurry was stirred for 10 minutes. Then, the mixture was filtered so as to prepare a first washed material. The same washing procedure was repeated to prepare a second washed material using the first washed material instead of the heated material.

[0130] Step 4) healing : the second washed material was placed in an alumina crucible and the alumina crucible was transferred into a furnace with 10 b / min dry air flow. The furnace heating follows a temperature profile from room temperature to 700 °C at 5 °C / min and that temperature was held for 10 hours before cooling down at 5 °C / min. The resulting cathode active material (Ex 1) was then transferred and kept into a dry room.

[0131] Example 2 (Ex 2)

[0132] Ex 2 was prepared following the protocol of Example 1 except that Step 4) was replaced by a drying of the second washed material at 100 °C for 5 hours.

[0133] Table 1. A summary of the sulfate salt treating, BET values, D50, Na and S composition and the electrochemical properties of CEx 1, Ex 1 and 2.

[0134] Comparative example 2 (CEx 2)

[0135] CEx 2 was prepared following the protocol of Example 1 but without the addition of U2SO4 during Step 2, and without Step 3) and Step 4).

[0136] Example 3 (Ex 3)

[0137] Step 1) Initially, 400 grams of Nio.4oMno.6oC03precursor with bed depth of 20 mm were transferred to an alumina crucible and the alumina crucible was placed in a furnace with 10 U / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 400 °C at 5 °C / min and then, the temperature was held at 400 °C for 10 hours before cooling down at 5 °C / min. A heated precursor was then transferred from the furnace into a dry room.

[0138] Step 2) 25.0 grams of the heated precursor were mixed with 0.88 grams of MgSO4and 11.5 grams of Li2CO3using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours so as to prepare a mixture. Later, 25 grams of the mixture were transferred to an alumina crucible. The alumina crucible was placed in a furnace with 10 b / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 500 °C at 5 °C / min then heating to 925 °C at 1.5 °C / min. That temperature was held for 10 hours before cooling down at 5 °C / min. A heated material was transferred from the furnace into a dry room.

[0139] Step 3) washing: 50 grams of the heated material were transferred into a 200 mL glass beaker with a stirring magnet. 75 grams of water were added into the glass beaker so as to prepare a slurry. The slurry was stirred for 15 minutes. Then, the slurry was filtered so as to prepare a first washed material. The same washing procedure was repeated to prepare a second washed material using the first washed material instead of the heated material.

[0140] Step 4) healing: the second washed material was placed in an alumina crucible and the alumina crucible was transferred into a furnace with 10 b / rnin dry air flow. The furnace heating follows a temperature heating profile from room temperature to 700 °C at 5 °C / min and that temperature was held for 10 hours before cooling down at 5 °C / min. The resulting cathode active material (Ex 3) was then transferred and kept into a dry room.

[0141] Example 4 (Ex 4)

[0142] Ex 4 was prepared following the protocol of Example 3 but without Step 3) and Step 4).

[0143] Example 5 (Ex 5)

[0144] Ex 5 was prepared following the protocol of Example 3 except that Step 4) was replaced by a drying of the second washed material at 100 °C for 5 hours. Table 2. A summary of the sulfate salt treating, BET values, D50, Na and S composition and the electrochemical properties of CEx 2, Ex 3 to 5.

[0145] Example 6 (Ex 6)

[0146] Step 1) Initially, 400 grams of Nio.4oMno.6oC03precursor with bed depth of 20 mm were transferred to an alumina crucible and the alumina crucible was placed in a furnace with 10 b / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 400 °C at 5 °C / min and then, the temperature was held at 400 °C for 10 hours before cooling down at 5 °C / min. The alumina crucible with a heated precursor was then transferred from the furnace into a dry room.

[0147] Step 2) 25.0 grams of the heated precursor were mixed with 2.0 grams of AI2(SO4)3°18H2O and 11.6 grams of Li2CO3using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours so as to prepare a mixture. Later, 25 grams of the mixture was transferred to an alumina crucible. The alumina crucible was 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 5 °C / min then heating to 925 °C at 1.5 °C / min. That temperature was held for 10 hours before cooling down at 5 °C / min. The alumina crucible with a heated material was transferred from the furnace into a dry room.

[0148] Step 3) washing: 50 grams of the heated material were transferred into a 200 mL glass beaker with a stirring magnet. 75 grams of water were added into the glass beaker so as to prepare a slurry. The slurry was stirred for 15 minutes. Then, the slurry was filtered so as to prepare a first washed material. The same washing procedure was repeated to prepare a second washed material using the first washed material instead of the heated material.

[0149] Step 4) healing : the second washed material was placed in an alumina crucible and the alumina crucible transferred into a furnace with 10 L / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 700 °C at 5 °C / min and that temperature was held for 10 hours before cooling down at 5 °C / min. The resulting cathode active material (Ex 6) was then transferred and kept into a dry room.

[0150] Example 7 (Ex 7)

[0151] Ex 7 was prepared following the protocol of Example 6 but without Step 3) and Step 4).

[0152] Example 8 (Ex 8)

[0153] Ex 8 was prepared following the protocol of Example 6 except that Step 4) was replaced by a drying of the second washed material at 100 °C for 5 hours.

[0154] Table 3. A summary of the sulfate salt treating, BET values, D50, Na and S composition and the electrochemical properties of Ex 6 to 8.

[0155] Example 9 (Ex 9)

[0156] Step 1) 400 grams of Nio.4oMn0.6oC03precursor with bed depth of 20 mm were transferred to an alumina crucible and the alumina crucible was placed in a furnace with 10 b / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 400 °C at 5 °C / min and then, the temperature was held at 400 °C for 10 hours before cooling down at 5 °C / min. The alumina crucible with a heated precursor was then transferred from the furnace into a dry room.

[0157] Step 2) 25.0 grams of the heated precursor were mixed with 2.1 grams of COSO4°7H2O and 11.7 grams of Li2CO3using 10 mm diameter zirconia (ZrO2) balls in the Turbula mixer for 4 hours so as to prepare a mixture. Later, 25 grams of the mixture was transferred to an alumina crucible. The alumina crucible was 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 5 °C / min then heating to 925 °C at 1.5 °C / min. That temperature was held for 10 hours before cooling down at 5 °C / min. The alumina crucible with a heated material was transferred from the furnace into a dry room. Step 3) washing: 50 grams of the heated material were transferred into a 200 mL glass beaker with a stirring magnet. 75 grams of water were added into the glass beaker so as to prepare a slurry and the slurry was stirred for 15 minutes. Then, the slurry was filtered so as to prepare a first washed material. The same washing procedure was repeated to prepare a second washed material using the first washed material instead of the heated material.

[0158] Step 4) healing: the second washed material was filtered and placed in an alumina crucible and the alumina crucible was transferred into a furnace with 10 b / min dry air flow. The furnace heating follows a temperature heating profile from room temperature to 700 °C at 5 °C / min and that temperature was held for 10 hours before cooling down at 5 °C / min. The resulting cathode active material (Ex 9) was then transferred and kept into a dry room.

[0159] Example 10 (Ex 10)

[0160] Ex 10 was prepared following the protocol of Example 9 but without Step 3) and Step 4).

[0161] Example 11 (Ex 11)

[0162] Ex 11 was prepared following the protocol of Example 9 but without except that Step 4) was replaced by a drying of the second washed material at 100 °C for 5 hours.

[0163] Table 4. A summary of the sulfate salt treating, BET values, D50, Na and S composition and the electrochemical properties of Ex 9 to 11.

Claims

CLAIMS1. A cathode active material for rechargeable batteries comprising lithium, Ml, and oxygen, wherein Ml comprises:- Ni in a content xl, wherein 0.0 < xl < 45.0 at%, relative to Ml;- Mn in a content yl, wherein 50.0 < yl < 98.0 at%, relative to Ml;- Co in a content zl, wherein 0.0 < zl < 15.0 at%, relative to Ml;- Na in a content wl, wherein 0.0 < wl < 2.0 at%, relative to Ml;- S in a content molar ratio ql, wherein 0.0 < ql < 5.0 at%, relative to Ml;- DI in a content molar ratio dl, wherein 0.0 < dl < 2.0 at%, relative to Ml, wherein Dl is an element different from Li, Ni, Mn, Co, Na, S and O; wherein the content of Ni, Mn, Co, Na, S and Dl is measured by ICP-OES, and xl+yl+zH-wH-qH-dl is 100.0 at%, and wherein the cathode active material has a BET value of at least 1.0 m2 / g.

2. The cathode active material according to claim 1, wherein 0.01 < wl < 1.0 at%, preferably 0.01 < wl < 0.5 at%, more preferably 0.01 < wl < 0.1 at%.

3. The cathode active material according to claim 1 or 2, wherein 0.02 < wl < 1.0 at%, preferably 0.03 < wl < 0.9 at%, more preferably 0.04 < wl < 0.1 at% .

4. The cathode active material according to any one of claims 1-3, wherein 0.01< ql < 3.5 at%, preferably wherein 0.02 < ql < 2.5 at%, more preferably 0.03< ql < 1.1 at%.

5. The cathode active material according to any one of claims 1-4, wherein 0.04< ql < 1.0 at%, preferably wherein 0.05 < ql < 0.5 at%, more preferably 0.09< ql < 0.2 at%.

6. The cathode active material according to any one of the previous claims, wherein- Ni in a content xl, wherein 10.0 < xl < 45.0 at%, relative to Ml; preferably 20.0 < xl < 40.0 at%, more preferably 35.0 < xl < 42.0 at%, relative to Ml;- Mn in a content yl, wherein 55.0 < yl < 90.0 at%, relative to Ml; preferably 58.0 < yl < 80.0 at%, more preferably 58.0 < yl < 70.0 at%, relative to Ml;- Co in a content zl, wherein 0.0 < zl < 10.0 at%, relative to Ml; preferably 0.0 < zl < 5.0 at%, more preferably zl is about 0.0 at%, relative to Ml.

7. The cathode active material according to any one of the previous claims, wherein the molar ratio of Li to Ml (mol / mol) is between 0.9 and 1.6, preferably between 1.0 and 1.5, more preferably between 1.1 and 1.4.

8. The cathode active material according to any one of the previous claims having a BET value between 0.5 and 8 m2 / g, preferably a BET value between 1.0 and 6.5 m2 / g, more preferably a BET value between 1.2 and 5.1 m2 / g.

9. The cathode active material according to any one of the previous claims having a formula LiW2Nia2Mnb2Coc2Nad2Se2D2f2O2, wherein:0.90 < w2 < 1.60,0.0 < a2 < 0.45,0.50 < b2 < 0.98,0.0 < c2 < 0.15,0.0 < d2 < 0.02,0.0 < e2 < 0.05,0.0 < f2 < 0.02, wherein D2 is an element different from Li, Ni, Mn, Co, Na, S, and O; wherein the content of Li, Ni, Mn, Co, Na, S and D2 is measured by ICP-OES and a2+b2+c2+d2+e2+f2 = 1.00.

10. The cathode active material according to claim 9 wherein 0.0002 < d2 < 0.01, preferably 0.0003 < d2 < 0.009, more preferably 0.0004 < d2 < 0.00111. The cathode active material according to claim 9 or 10, wherein 0.0004 < e2 < 0.01, preferably wherein 0.0005 < e2 < 0.005, more preferably 0.0009 < e2 < 0.002.

12. The cathode active material according to any one of claims 9-11, wherein0.90 < w2 < 1.50, preferably 0.90 < w2 < 1.30, more preferably w2 is about1.2;0.20 < a2 < 0.45, preferably 0.35 < a2 < 0.40, more preferably a2 is about 0.40;0.55 < b2 < 0.78, preferably 0.58 < b2 < 0.70, more preferably b2 is about 0.60;0.0 < c2 < 0.10, preferably 0.0 < c2 < 0.05, more preferably c2 is about 0.0;0.0 < f2 < 0.01, more preferably 0.0 < f2 < 0.005, more preferably f2 is about 0.0.

13. A process for manufacturing a cathode active material, preferably the cathode active material according to any one of claims 1-12, comprising the following steps:Step 1) providing a first nickel-manganese carbonate precursor;Step 2) optionally heating the first nickel-manganese carbonate precursor at a temperature in a range of 300 to 500 °C, preferably 400 °C;Step 3) mixing the first nickel-manganese carbonate precursor or the heated first nickel-manganese carbonate precursor with:U2SO4 in a content of 1 to 5 mol% of sulfur present in the U2SO4 relative to the first nickel-manganese carbonate precursor or the heated first nickel- manganese carbonate precursor; and a first lithium source in a content of 100 to 150 mol% of lithium present in the first lithium source relative to the first nickel-manganese carbonate precursor or the heated first nickel-manganese carbonate precursor; wherein the first lithium source is selected from U2CO3, LiOH and combinations thereof, preferably the lithium source is U2CO3,Step 4) heating the mixture from Step 3) at a temperature in a range of 800 to 1000 °C to afford a mixture, preferably mixing and stirring at a temperature of 925 °C to prepare a heated material;Step 5) washing the heated material with water;Step 6) optionally drying the washed material at a temperature in a range of 80 to 120 °C, preferably at 100 °C; andStep 7) heating the washed or dried material at a temperature in a range of 600 to 800 °C to afford the cathode active material, preferably heating the washed or dried material at 700 °C, wherein the nickel manganese carbonate precursor comprises M2, carbon and oxygen, wherein M2 comprises:Ni in a content x3, wherein 0.0 < x3 < 60 at% relative to M2;Mn in a content y3, wherein 40.0 < y3 < 98.0 at% relative to M2;Co in a content z3, wherein 0.0 < z3 < 15.0 at%, relative to M2; andD3 in a content d3, wherein 0.0 < d3 < 2.0 at% relative to M2, wherein D3 is an element different from Ni, Mn, carbon, and oxygen; wherein the content of Ni, Mn and D3 is measured by ICP-OES, and x3+y3+d3 = 100.0 at%.

14. A process for manufacturing a cathode active material, preferably the cathode active material according to any one of claims 1-12, comprising the following steps:Step 1) providing a second nickel-manganese carbonate precursor;Step 2) optionally heating the second nickel-manganese carbonate precursor at a temperature in a range of 300 to 500 °C;Step 3) mixing the second nickel-manganese carbonate precursor or to the heated second nickel-manganese carbonate precursor with: a sulfate salt in a content of 1 to 5 mol% of sulfur present in the sulfate salt relative to the nickel-manganese carbonate precursor or to the heated second nickel-manganese carbonate precursor, wherein the sulfate salt is selected from the group consisting of MgSC , Al2(SO4)3 and CoSC ; and a second lithium source in a content of 100 to 150 mol% of lithium present in the second lithium source relative to the second nickel-manganese carbonate precursor or to the heated second nickel-manganese carbonate precursor; wherein the second lithium source is selected from U2CO3, LiOH and combinations thereof,Step 4) heating the mixture from Step 3) at a temperature in a range of 800 to 1000 °C to afford the cathode active material;Step 5) optionally washing the cathode active material with water;Step 6) optionally drying the washed cathode active material at a temperature in a range of 80 to 120 °C; andStep 7) optionally heating the washed or dried cathode active material at a temperature in a range of 600 to 800 °C to afford the heated cathode active material, wherein the second nickel manganese carbonate precursor comprises M3, carbon and oxygen, wherein M3 comprises:Ni in a content x4, wherein 0.0 < x4 < 60 at% relative to M3;Mn in a content y4, wherein 40.0 < y4 < 98.0 at% relative to M3;Co in a content z4, wherein 0.0 < z4 < 15.0 at%, relative to M3; andD4 in a content d4, wherein 0.0 < d4 < 2.0 at% relative to M3, wherein D4 is an element different from Ni, Mn, carbon, and oxygen; wherein the content of Ni, Mn and D4 is measured by ICP-OES, and x4+y4+d4 = 100.0 at%.

15. A battery comprising the cathode material according to any of the claims 1-12.

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