Layered oxide positive electrode material and preparation method therefor, positive electrode composition, sodium-ion secondary battery and use

Abstract

A layered oxide positive electrode material and a preparation method therefor, a positive electrode composition, a sodium-ion secondary battery and the use. The layered oxide positive electrode material has the following general formula: NaaNibCucMndTieMfOg, wherein M is a doping element, a=0.75-0.95, b=0.33-0.45, c=0.03-0.15, d=0.20-0.45, e=0.05-0.20, f=0-0.1, and g=1.80-2.20. In an XRD pattern of the layered oxide positive electrode material, the peak intensity ratio I(101) / I(003)=0.02-0.15, the peak intensity ratio I(101) / I(012)=0.35-0.47, and the peak intensity ratio I(101) / I(006)=0.08-0.57.

Description

Layered oxide positive electrode material, preparation method thereof, positive electrode composition, sodium ion secondary battery and use thereof

[0001] This application claims priority to Chinese Patent Application No. 202410200401.5 filed on February 23, 2024, and the contents of the above-mentioned Chinese patent application disclosure are hereby incorporated by reference in their entirety as a part of this application. Technical Field

[0002] The present invention generally relates to the field of energy storage technology, in particular to the field of sodium ion secondary batteries. Specifically, the present invention relates to layered oxide positive electrode materials, methods for preparing the same, positive electrode compositions comprising the same, sodium ion secondary batteries comprising the positive electrode compositions, and uses of the sodium ion secondary batteries. Background Art

[0003] Existing secondary batteries primarily include nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, and lithium-ion batteries. Lithium-ion batteries are widely used due to their small size, light weight, high specific energy, lack of memory effect, pollution-free operation, low self-discharge, and long cycle life. However, limited lithium resources and high extraction costs increase the cost of lithium-ion batteries, making them inadequate for low-cost, large-scale applications. In contrast, sodium, which belongs to the same main group as lithium and has similar physical and chemical properties, is abundant and inexpensive. Consequently, the development of sodium-ion secondary batteries for large-scale energy storage devices has attracted considerable attention.

[0004] Currently, sodium-ion secondary battery cathode materials primarily utilize layered oxides, which primarily include two structural materials: O3-phase (or O3-type) crystal structures and P2-phase (or O3-type) crystal structures. O3-type sodium-ion battery cathode materials have become a research hotspot since their inception due to their high specific capacity and ease of synthesis.

[0005] However, the potential of the sodium-ion battery positive electrode materials currently developed is relatively low, and their specific capacity, especially the cycle specific capacity at higher discharge rates, is still relatively low, which restricts the marketization of sodium-ion batteries.

[0006] Therefore, there is still a need to find a method for providing a layered oxide cathode material for sodium ion secondary batteries with high potential and improved high rate performance (including initial discharge capacity and cycle performance at higher rates). Summary of the Invention

[0007] The present invention is made in view of the above problems existing in the prior art.

[0008] In a first aspect, the present invention relates to a layered oxide cathode material having the following general formula:

[0009] Naa Ni b Cu c Mn d Ti e M f O g ,

[0010] in:

[0011] M is one or more elements selected from Li, Fe, B, Mg, Al, Si, Ca, Zr, Zn, Ta, Mo, W, La, Sr, Sb, Ce, Nb, Sn, and Y;

[0012] a=0.75-0.95, preferably 0.85-0.92, preferably 0.90-0.92;

[0013] b = 0.33-0.45, preferably 0.35-0.45, preferably 0.35-0.40;

[0014] c = 0.03-0.15, preferably 0.05-0.15, preferably 0.10-0.15;

[0015] d = 0.20-0.45, preferably 0.35-0.45, preferably 0.35-0.40;

[0016] e=0.05-0.20, preferably 0.05-0.15, preferably 0.10-0.15;

[0017] f = 0-0.1, preferably 0-0.05; and

[0018] g=1.80-2.20;

[0019] And in the XRD diffraction pattern of the layered oxide positive electrode material,

[0020] The peak intensity ratio of (101) crystal plane to (003) crystal plane I (101) / I (003) =0.02-0.15, preferably 0.02-0.14;

[0021] Peak intensity ratio of (101) crystal plane to (012) crystal plane I (101) / I (012) =0.35-0.47, preferably 0.35-0.45, preferably 0.38-0.43; and

[0022] Peak intensity ratio of (101) crystal plane to (006) crystal plane I (101) / I (006) =0.08-0.57, preferably 0.08-0.55, preferably 0.08-0.53.

[0023] In a second aspect, the present invention relates to a method for preparing the layered oxide positive electrode material of the first aspect, comprising the following steps:

[0024] Step 1:

[0025] (1-1) mixing a Na source, a Cu source, a Mn source, a Ni source, a Ti source, and an optional M source in a stoichiometric ratio to obtain a precursor mixture; or

[0026] (1-2) synthesizing a first precursor containing Ni, Cu, and Mn by coprecipitating Ni, Cu, and Mn, and mixing a Na source, a first precursor, a Ti source, and an optional M source in a stoichiometric ratio to obtain a precursor mixture; or

[0027] (1-3) synthesizing a second precursor containing Ni, Cu, Mn, and Ti by coprecipitating Ni, Cu, Mn, and Ti, and mixing a Na source, the second precursor, and an optional M source in a stoichiometric ratio to obtain a precursor mixture;

[0028] and

[0029] Step 2: sintering the precursor mixture obtained in step 1, cooling it, and optionally crushing and sieving it;

[0030] Step 3: The product obtained in step 2 is subjected to secondary sintering, cooling, and optionally crushing and sieving to obtain the layered oxide positive electrode material.

[0031] In a third aspect, the present invention relates to a positive electrode composition, which is a positive electrode composition for a sodium ion secondary battery, comprising the layered oxide positive electrode material of the first aspect of the present invention.

[0032] In a fourth aspect, the present invention relates to a sodium ion secondary battery comprising the positive electrode composition of the third aspect of the present invention.

[0033] In a fifth aspect, the present invention relates to the use of the sodium ion secondary battery of the fourth aspect of the present invention in an energy storage device, especially an energy storage device for solar power generation, wind power generation, smart grid peak regulation, distributed power station, backup power supply or communication base station.

[0034] The applicant has found that by controlling the content of Na, Ni, Cu, Mn, Ti and the optional doping element M in the layered oxide positive electrode material and performing two sintering processes, the crystallographic structure and / or orientation and / or morphology of the obtained layered oxide positive electrode material can be improved so that it has a specific XRD diffraction pattern, especially a specific peak intensity ratio between specific diffraction peaks. The resulting layered oxide positive electrode material can have improved electrochemical properties, especially the first discharge capacity and cycle performance (such as discharge capacity) at a higher rate (such as 1C), and has a high potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] To more clearly illustrate the technical solution of the present invention, the following briefly describes the drawings required for describing the embodiments. It should be understood that these drawings are only intended to facilitate easier understanding of the present invention by those skilled in the art and are not intended to limit the scope of the present invention.

[0036] 1-2 show scanning electron microscope images of the sintered products prepared in Examples 4A-4B at a magnification of 10,000, respectively.

[0037] 3-4 show scanning electron microscope images of the sintered products prepared in Examples 5A-5B at a magnification of 10,000, respectively.

[0038] 5-6 show scanning electron microscope images of the sintered products prepared in Examples 6A-6B at a magnification of 10,000, respectively.

[0039] 7-8 show scanning electron microscope images of the sintered products prepared in Examples 7A-7B at a magnification of 10,000, respectively. DETAILED DESCRIPTION

[0040] In order to make the invention objectives, technical solutions and beneficial technical effects of this application clearer, this application will be described in detail below. It should be noted that the various aspects, features, implementation methods, and advantages described in this application may be compatible and / or combinable.

[0041] Unless otherwise specified, the meanings of the technical terms in this specification are the same as those generally understood by those skilled in the art.

[0042] Those skilled in the art will understand that in this application, unless otherwise specified, a number containing n significant digits after the decimal point actually also covers the result of rounding a number containing more significant digits after the decimal point to n significant digits after the decimal point. For example, 0.16 actually covers all numbers in the range from greater than or equal to 0.155 to less than 0.165; 0.166 actually covers all numbers in the range from greater than or equal to 0.1655 to less than 0.1665, and so on.

[0043] The present invention relates to a layered oxide positive electrode material, a preparation method thereof, a positive electrode composition comprising the layered oxide positive electrode material, a sodium ion secondary battery comprising the positive electrode composition, and uses of the sodium ion secondary battery.

[0044] The present invention will be described in detail below.

[0045] Layered oxide cathode materials

[0046] In a first aspect, the present invention relates to a layered oxide cathode material having the following general formula:

[0047] Na a Ni b Cu c Mn d Ti e M f O g ,

[0048] in:

[0049] M is one or more elements selected from Li, Fe, B, Mg, Al, Si, Ca, Zr, Zn, Ta, Mo, W, La, Sr, Sb, Ce, Nb, Sn, and Y;

[0050] a=0.75-0.95, preferably 0.85-0.92, preferably 0.90-0.92;

[0051] b = 0.33-0.45, preferably 0.35-0.45, preferably 0.35-0.40;

[0052] c = 0.03-0.15, preferably 0.05-0.15, preferably 0.10-0.15;

[0053] d = 0.20-0.45, preferably 0.35-0.45, preferably 0.35-0.40;

[0054] e=0.05-0.20, preferably 0.05-0.15, preferably 0.10-0.15;

[0055] f = 0-0.1, preferably 0-0.05; and

[0056] g=1.80-2.20;

[0057] And in the XRD diffraction pattern of the layered oxide positive electrode material,

[0058] The peak intensity ratio of (101) crystal plane to (003) crystal plane I (101) / I (003)=0.02-0.15, preferably 0.02-0.14;

[0059] Peak intensity ratio of (101) crystal plane to (012) crystal plane I (101) / I (012) =0.35-0.47, preferably 0.35-0.45, preferably 0.38-0.43; and

[0060] Peak intensity ratio of (101) crystal plane to (006) crystal plane I (101) / I (006) =0.08-0.57, preferably 0.08-0.55, preferably 0.08-0.53.

[0061] The applicant has found that when the layered oxide positive electrode material has a defined content of Na, Ni, Cu, Mn, Ti and an optional doping element M and has a defined XRD peak intensity ratio, the resulting layered oxide positive electrode material has a high potential and improved electrochemical performance, especially the first discharge capacity and cycle performance (e.g., discharge capacity) at a higher rate (e.g., 1C).

[0062] In an embodiment, the subscript a of the sodium element is 0.75-0.95, preferably 0.85-0.92, preferably 0.90-0.92; for example, a can be 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, or a range limited by any two of them.

[0063] In an embodiment, the subscript b of the nickel element is 0.33-0.45, preferably 0.35-0.45, preferably 0.35-0.40; for example, b can be 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, or a range limited by any two of them.

[0064] In an embodiment, the subscript c of the copper element is 0.03-0.15, preferably 0.05-0.15, preferably 0.10-0.15; for example, c can be 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, or a range limited by any two thereof.

[0065] In an embodiment, the subscript d of the manganese element is 0.20-0.45, preferably 0.35-0.45, preferably 0.35-0.40; for example, d can be 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, or a range limited by any two of them.

[0066] In an embodiment, the subscript e of the titanium element is 0.05-0.20, preferably 0.05-0.15, preferably 0.10-0.15; for example, e can be 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, or a range limited by any two thereof.

[0067] In an embodiment, the subscript f of the doping element M is 0-0.1, preferably 0-0.05; for example, f can be 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, or a range defined by any two of them.

[0068] In one embodiment, the layered oxide cathode material is undoped, i.e., f=0 (in other words, no doping element M is present). In one embodiment, the layered oxide cathode material is doped, i.e., f>0 (in other words, a doping element M is present). When a doping element M is present, M may be one or more elements selected from Li, Fe, B, Mg, Al, Si, Ca, Zr, Zn, Ta, Mo, W, La, Sr, Sb, Ce, Nb, Sn, and Y, for example, any one element selected from Li, Fe, B, Mg, Al, Si, Ca, Zr, Zn, Ta, Mo, W, La, Sr, Sb, Ce, Nb, Sn, and Y, or a combination of any two, three, or more elements thereof. When M is a combination of two, three or more elements, the subscripts of the two, three or more elements are each in the range of greater than 0 to less than 0.1, for example, in the range of 0.01-0.09 or any value within this range as stated above, and the sum thereof is f=0.01-0.10.

[0069] In an embodiment, g=1.80-2.20; for example, g can be 1.80, 1.81, 1.82, 1.83, 1.84, 1.85, 1.86, 1.87, 1.88, 1.89, 1.90, 1.91, 1.92, 1.93, 1.94, 1.95, 1.96, 1.97, 1.98, 1.99, 2.00, 2.01, 2.02, 2.03, 2.04, 2.05, 2.06, 2.07, 2.08, 2.09, 2.10, 2.11, 2.12, 2.13, 2.14, 2.15, 2.16, 2.17, 2.18, 2.19, 2.20, or a range limited by any two of them.

[0070] Those skilled in the art will understand that the subscripts of each element in the layered oxide positive electrode material (i.e., a, b, d, d, e, f, and g) will satisfy the valence balance, that is, the layered oxide positive electrode material as a whole is electrically neutral. In the present application, including in the embodiments, for the subscript g of the oxygen element, even if g is not equal to 2, it is sometimes directly recorded as "2", "2.0" or "2.00" for simplicity. However, those skilled in the art will understand that for the case where the subscript of the oxygen element is not equal to 2, even if it is recorded as "2", it actually means "2+δ" (δ=-0.20 to 0.20), and based on the proportion of the raw materials used and the valence of the relevant elements in the raw materials, those skilled in the art will understand and can easily calculate the g value actually represented by the subscript 2 of the oxygen element in this case, which is well within the capabilities of those skilled in the art.

[0071] In an embodiment, in the XRD diffraction pattern of the layered oxide positive electrode material, the peak intensity ratio of the (101) crystal plane to the (003) crystal plane is (101) / I (003) (i.e., the diffraction peak intensity I of the (101) crystal plane (101) The diffraction peak intensity I of (003) crystal plane (003) ratio) = 0.02-0.15, preferably 0.02-0.14; for example, it can be 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, or the range limited by any two of them.

[0072] In an embodiment, in the XRD diffraction pattern of the layered oxide positive electrode material, the peak intensity ratio of the (101) crystal plane to the (012) crystal plane is (101) / I (012) (i.e., the diffraction peak intensity I of the (101) crystal plane (101)The diffraction peak intensity I of (003) crystal plane (012) ) = 0.35-0.47, preferably 0.35-0.45, preferably 0.38-0.43; for example, it can be 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, or a range limited by any two of them.

[0073] In an embodiment, in the XRD diffraction pattern of the layered oxide positive electrode material, the peak intensity ratio of the (101) crystal plane to the (006) crystal plane is (101) / I (006) (i.e., the diffraction peak intensity I of the (101) crystal plane (101) The diffraction peak intensity I of (003) crystal plane (006) 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85 0.54, 0.55, 0.56, 0.57, or a range defined by any two of them.

[0074] In this application, unless otherwise specified, when referring to the intensity and peak intensity ratio of XRD diffraction peaks, the peak intensity refers to the integrated area of ​​the diffraction peak, and the peak intensity ratio refers to the ratio of the integrated areas of the diffraction peaks.

[0075] The applicant has found that when the contents of Na, Ni, Cu, Mn, Ti and the optional doping element M in the layered oxide positive electrode material are within the specified ranges, and the material has the specific XRD diffraction pattern as described above (specific peak intensity ratios between specific diffraction peaks, i.e., I (101) / I (003) , I (101) / I (012) and I (101) / I (006) ), (for example, relative to the Na content and peak intensity ratio I (101) / I (003) , I (101) / I (012) and I (101) / I (006) Any layered oxide positive electrode material not within the specified range) The layered oxide positive electrode material has improved electrochemical properties, especially the first discharge capacity and cycle performance (such as discharge capacity) at a higher rate (such as 1C).

[0076] In a preferred embodiment, I (101) / I (003) =0.02-0.14, I (101) / I (012) =0.35-0.45, and I (101) / I (006) =0.08-0.55; When the layered oxide positive electrode material has this preferred peak intensity ratio, it has further improved cycle performance (such as discharge capacity) at a higher rate (such as 1C). More preferably, I (101) / I (003) =0.02-0.14, I (101) / I (012) =0.38-0.43, and I (101) / I (006) =0.08-0.53, when the layered oxide positive electrode material has this more preferred peak intensity ratio, it has even further improved cycle performance (eg, discharge capacity) at a higher rate (eg, 1C).

[0077] In a preferred embodiment, the XRD diffraction peaks of the layered oxide positive electrode material may further satisfy any one or more of the following, for example, any one, two, or three of the following, preferably all (ie, three):

[0078] Peak intensity ratio of (006) crystal plane to (003) crystal plane I (006) / I (003) =0.13-0.27, preferably 0.16-0.27, more preferably 0.18-0.27, for example 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, or a range defined by any two thereof;

[0079] The peak intensity ratio of (101) crystal plane to (104) crystal plane I (101) / I (104) =0.08-0.12, for example, 0.09-0.12, preferably 0.09-0.11, more preferably 0.10-0.11, for example, 0.08, 0.09, 0.10, 0.11, 0.12, or a range defined by any two thereof;

[0080] Peak intensity ratio of (012) crystal plane to (104) crystal plane I (012) / I (104) =0.21-0.29, for example, 0.22-0.28, preferably 0.24-0.27, more preferably 0.24-0.26, for example, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, or the range defined by any two thereof.

[0081] In a preferred embodiment, I (006) / I (003) =0.13-0.27, I (101) / I (104) =0.08-0.12, and I (012) / I (104) =0.21-0.29; preferably, I (006) / I (003) =0.16-0.27, I (101) / I (104) =0.09-0.12, and I (012) / I (104) =0.22-0.28, within the preferred peak intensity ratio range, the layered oxide positive electrode material has further improved cycle performance (such as discharge capacity) at a higher rate (such as 1C); more preferably, I (006) / I (003) =0.16-0.27 For example, 0.18-0.27, I (101) / I (104) =0.09-0.11, and I (012) / I (104) =0.24-0.27, within this more preferred peak intensity ratio range, the layered oxide positive electrode material has further improved cycle performance (such as discharge capacity) at a higher rate (such as 1C); further preferably, I (006) / I (003) =0.16-0.27 For example, 0.18-0.27, I (101) / I (104) =0.10-0.11, and I (012) / I (104) =0.24-0.26. Within this further preferred range of peak intensity ratio, the layered oxide positive electrode material has further improved cycle performance (eg, discharge capacity) at a higher rate (eg, 1C).

[0082] In a preferred embodiment, the XRD diffraction peaks of the layered oxide positive electrode material may further satisfy any one or more of the following, such as any one, two, three or four, preferably all (four):

[0083] The peak intensity ratio of (012) crystal plane to (003) crystal plane I (012) / I (003) =0.05-0.36 (e.g., 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, or a range bounded by any two thereof);

[0084] Peak intensity ratio of (104) crystal plane to (003) crystal plane I (104) / I (003)=0.19-1.46 (e.g., 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 9, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0 .83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.00, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.10, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16 6, 1.17, 1.18, 1.19, 1.20, 1.21, 1.22, 1.23, 1.24, 1.25, 1.26, 1.27, 1.28, 1.29, 1.30, 1.31, 1.32, 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.40, 1.41, 1.42, 1.43, 1.44, 1.45, 1.46, or the range defined by any two of them);

[0085] The peak intensity ratio of (006) crystal plane to (104) crystal plane I (006) / I (104)=0.19-1.24 (e.g., 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0 .44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0 .72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1 .00, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.10, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19, 1.20, 1.21, 1.22, 1.23, 1.24, or the range bounded by any two of them);

[0086] Peak intensity ratio of (006) crystal plane to (012) crystal plane I (006) / I (012)=0.76-5.02 (e.g., 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0 .98, 0.99, 1.00, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.10, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19, 1.20, 1.21, 1.22, 1 .23, 1.24, 1.25, 1.26, 1.27, 1.28, 1.29, 1.30, 1.31, 1.32, 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.40, 1.41, 1.42, 1.43, 1.44, 1.45, 1.46, 1.47, 1 .48, 1.49, 1.50, 1.51, 1.52, 1.53, 1.54, 1.55, 1.56, 1.57, 1.58, 1.59, 1.60, 1.61, 1.62, 1.63, 1.64, 1.65, 1.66, 1.67, 1.68, 1.69, 1.70, 1.71, 1.72, 1 .73, 1.74, 1.75, 1.76, 1.77, 1.78, 1.79, 1.80, 1.81, 1.82, 1.83, 1.84, 1.85, 1.86, 1.87, 1.88, 1.89, 1.90, 1.91, 1.92, 1.93, 1.94, 1.95, 1.96, 1.97, 1 .98, 1.99, 2.00, 2.01, 2.02, 2.03, 2.04, 2.05, 2.06, 2.07, 2.08, 2.09, 2.10, 2.11, 2.12, 2.13, 2.14, 2.15, 2.16, 2.17, 2.18, 2.19, 2.20, 2.21, 2.22, 2 .23, 2.24, 2.25, 2.26, 2.27, 2.28, 2.29, 2.30, 2.31, 2.32, 2.33, 2.34, 2.35, 2.36, 2.37, 2.38, 2.39, 2.40, 2.41, 2.42, 2.43, 2.44, 2.45, 2.46, 2.47, 2 .48, 2.49, 2.50, 2.51, 2.52, 2.53, 2.54, 2.55, 2.56, 2.57, 2.58, 2.59, 2.60, 2.61, 2.62, 2.63, 2.64, 2.65, 2.66, 2.67, 2.68, 2.69, 2.70, 2.71, 2.72, 2.73、2.74、2.75、2.76、2.77、2.78、2.79、2.80、2.81、2.82、2.83、2.84、2.85、2.86、2.87、2.88、2.89、2.90、2.91、2.92、2.93、2.94、2.95、2.96、2.97、2.98、2.99、3.00、3.01、3.02、3.03、3.04、3.05、3.06、3.07、3.08、3.09、3.10、3.11、3.12、3.13、3.14、3.15、3.16、3.17、3.18、3.19、3.20、3.21、3.22、3.23、3.24、3.25、3.26、3.27、3.28、3.29、3.30、3.31、3.32、3.33、3.34、3.35、3.36、3.37、3.38、3.39、3.40、3.41、3.42、3.43、3.44、3.45、3.46、3.47、3.48、3.49、3.50、3.51、3.52、3.53、3.54、3.55、3.56、3.57、3.58、3.59、3.60、3.61、3.62、3.63、3.64、3.65、3.66、3.67、3.68、3.69、3.70、3.71、3.72、3.73、3.74、3.75、3.76、3.77、3.78、3.79、3.80、3.81、3.82、3.83、3.84、3.85、3.86、3.87、3.88、3.89、3.90、3.91、3.92、3.93、3.94、3.95、3.96、3.97、3.98、3.99、4.00、4.01、4.02、4.03、4.04、4.05、4.06、4.07、4.08、4.09、4.10、4.11、4.12、4.13、4.14、4.15、4.16、4.17、4.18、4.19、4.20、4.21、4.22、4.23、4.24、4.25、4.26、4.27、4.28、4.29、4.30、4.31、4.32、4.33、4.34、4.35、4.36、4.37、4.38、4.39、4.40、4.41、4.42、4.43、4.44、4.45、4.46、4.47、4.48、4.49、4.50、4.51、4.52、4.53、4.54、4.55、4.56、4.57、4.58、4.59、4.60、4.61、4.62、4.63、4.64、4.65、4.66、4.67、4.68、4.69、4.70、4.71、4.72、4.4.94, 4.95, 4.96, 4.97, 4.98, 4.99, 5.00, 5.01, 5.02, or a range defined by any two of them).

[0087] Within the preferred peak intensity ratio range, the layered oxide positive electrode material may have improved electrochemical performance, such as cycle performance (eg, discharge capacity) at a higher rate (eg, 1C).

[0088] In a preferred embodiment, b+c=0.40-0.60, preferably 0.45-0.55, such as 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, or limited by any two thereof and d + e = 0.40-0.60, preferably 0.40-0.55, for example 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, or a range defined by any two thereof.

[0089] In a preferred embodiment, the layered oxide positive electrode material may further satisfy any one or more of the following conditions, for example, any one, two, three, four or five, preferably all (five):

[0090] Particle size D10 = 1-15 μm, preferably 2-8 μm (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 μm, or a range defined by any two thereof);

[0091] Particle size D50 = 2-35 μm, preferably 5-20 μm (for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 μm, or a range defined by any two thereof);

[0092] 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70 μm, or a range defined by any two thereof;

[0093] (D90-D10) / D50≤2.0, preferably 1.0-1.8, preferably 1.2-1.7 (for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or a range defined by any two thereof);

[0094] BET specific surface area = 0.1-1.5m 2 / g, preferably 0.2-0.8m 2 / g, preferably 0.2-0.6m 2 / g, preferably 0.3-0.6m 2 / g (e.g. 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5m 2 / g, or the range defined by any two of them).

[0095] In this application, unless otherwise specified, particle size D10 refers to the particle size at which 10% of the volume of particles in the cumulative volume distribution curve has a particle size below the stated value; particle size D50 refers to the particle size at which 50% of the volume of particles in the cumulative volume distribution curve has a particle size below the stated value; and particle size D90 refers to the particle size at which 90% of the volume of particles in the cumulative volume distribution curve has a particle size below the stated value. Each particle size can be measured, for example, using a laser scattering method commonly used in the art. For example, it can be measured using a Malvern particle size analyzer commonly used in the art, such as the MASTERSIZER-3000.

[0096] In an embodiment, the layered oxide cathode material belongs to the R-3m space group and has an O3 phase crystal structure.

[0097] The layered oxide cathode material has a high potential and can thus be used to manufacture high-voltage batteries. For example, when sodium is used as the negative electrode and the layered oxide cathode material is used as the positive electrode, the manufactured battery can be charged and discharged in the range of 2.0-4.3V, for example, at a relatively high rate (e.g., 1C), and has good cycling performance.

[0098] Preparation method of layered oxide positive electrode material

[0099] In a second aspect, the present invention provides a method for preparing a layered oxide positive electrode material according to the first aspect of the present invention, comprising the following steps:

[0100] Step 1:

[0101] (1-1) mixing a Na source, a Cu source, a Mn source, a Ni source, a Ti source, and an optional M source in a stoichiometric ratio to obtain a precursor mixture; or

[0102] (1-2) synthesizing a first precursor containing Ni, Cu, and Mn by coprecipitating Ni, Cu, and Mn, and mixing a Na source, a first precursor, a Ti source, and an optional M source in a stoichiometric ratio to obtain a precursor mixture; or

[0103] (1-3) synthesizing a second precursor containing Ni, Cu, Mn, and Ti by coprecipitating Ni, Cu, Mn, and Ti, and mixing a Na source, the second precursor, and an optional M source in a stoichiometric ratio to obtain a precursor mixture;

[0104] and

[0105] Step 2: sintering the precursor mixture obtained in step 1, cooling it, and optionally crushing and sieving it;

[0106] Step 3: The product obtained in step 2 is subjected to secondary sintering, cooling, and optionally crushing and sieving to obtain the layered oxide positive electrode material.

[0107] Each step is described in detail below.

[0108] Step 1

[0109] In step 1, a precursor mixture is prepared.

[0110] Step 1 can be performed as follows: (1-1) mixing a Na source, a Cu source, a Mn source, a Ni source, a Ti source, and an optional M source in a stoichiometric ratio to obtain a precursor mixture.

[0111] The sodium source used is not particularly limited and can be any sodium-containing compound known to those skilled in the art for preparing a positive electrode material for a sodium ion secondary battery. Preferably, the sodium source ultimately does not introduce any elements other than the elements constituting the layered oxide positive electrode material. The sodium source can be one or more of the forms of sodium-containing oxides, hydroxides, salts, etc. In one embodiment, the Na source can be one or more selected from the following compounds: sodium carbonate, sodium bicarbonate, sodium nitrate, sodium acetate, sodium oxalate, sodium hydroxide, sodium chloride, sodium sulfate, and sodium oxide.

[0112] The Ni source used is not particularly limited and can be any nickel-containing compound known to those skilled in the art for preparing a positive electrode material for a sodium ion secondary battery. Preferably, the nickel source ultimately does not introduce any elements other than the elements constituting the layered oxide positive electrode material. In one embodiment, the Ni source can be one or more selected from the following compounds: nickel carbonate, nickel nitrate, nickel acetate, nickel oxalate, nickel hydroxide, nickel sulfate, nickel chloride, and nickel oxide.

[0113] The Cu source used is not particularly limited and can be any copper-containing compound known to those skilled in the art for use in preparing positive electrode materials for sodium-ion secondary batteries. Preferably, the copper source ultimately does not introduce any elements other than those constituting the layered oxide positive electrode material. In one embodiment, the Cu source can be one or more compounds selected from the following: copper carbonate, copper nitrate, copper acetate, copper oxalate, copper hydroxide, copper sulfate, copper chloride, and copper oxide.

[0114] The Mn source used is not particularly limited and can be any manganese-containing compound known to those skilled in the art for use in preparing positive electrode materials for sodium-ion secondary batteries. Preferably, the manganese source ultimately does not introduce any elements other than those constituting the layered oxide positive electrode material. In one embodiment, the Mn source can be one or more selected from the following compounds: manganese carbonate, manganese nitrate, manganese acetate, manganese oxalate, manganese hydroxide, manganese sulfate, manganese chloride, and manganese oxide (e.g., manganese dioxide).

[0115] The Ti source used is not particularly limited and can be any titanium-containing compound known to those skilled in the art for use in preparing positive electrode materials for sodium-ion secondary batteries. Preferably, the titanium source ultimately does not introduce any elements other than those constituting the layered oxide positive electrode material. In one embodiment, the Ti source can be one or more compounds selected from the following: titanium nitrate, titanium oxalate, titanium hydroxide, titanium sulfate, titanyl sulfate, titanium chloride, and titanium oxide.

[0116] The M source is optionally present, wherein the element M in the M source is selected from one or more of the following elements: Li, Fe, B, Mg, Al, Si, Ca, Zr, Zn, Ta, Mo, W, La, Sr, Sb, Ce, Nb, Sn, Y. The M source is not particularly limited and may be any compound containing the element M known to those skilled in the art for preparing a positive electrode material for a sodium ion secondary battery. Preferably, the M source ultimately does not introduce other elements other than the elements constituting the layered oxide positive electrode material. In one embodiment, the M source may be one or more in the form of an oxide, a salt, or a hydroxide. For example, when M is a metal element (e.g., Li, Fe, Mg, Al, Ca, Zr, Zn, Ta, Mo, W, La, Sr, Sb, Ce, Nb, Sn, Y), the M source may be one or more of the following compounds of the element M: carbonates, bicarbonates, nitrates, acetates, oxalates, hydroxides, sulfates, chlorides, and oxides. When a B source is used, the B source may be, for example, one or more compounds selected from the group consisting of boron oxide and boric acid; when a Si source is used, the Si source may be, for example, silicon dioxide or silicic acid.

[0117] The Na source, Cu source, Mn source, Ni source, Ti source and optional M source can each be provided independently in the form of its own compound, or in the form of a compound (or complex) containing two or more thereof (for example, when M includes Si, at least a portion of Na can also be provided in the form of, for example, sodium silicate).

[0118] Alternatively, step 1 can be performed as follows: (1-2) synthesizing a first precursor containing Ni, Cu and Mn by co-precipitating Ni, Cu and Mn, mixing a Na source, a first precursor and a Ti source and an optional M source in a stoichiometric ratio to obtain a precursor mixture.

[0119] Alternatively, step 1 can also be performed as follows: (1-3) Ni, Cu, Mn and Ti are co-precipitated to synthesize a second precursor containing Ni, Cu, Mn and Ti, and a Na source and the second precursor and an optional M source are mixed in a stoichiometric ratio to obtain a precursor mixture.

[0120] The synthesis of the first precursor (ie, the ternary precursor containing Ni, Cu, and Mn) and the second precursor (ie, the quaternary precursor containing Ni, Cu, Mn, and Ti) can be performed by any suitable method known in the art without particular limitation.

[0121] For example, the first precursor can be prepared by dissolving a soluble salt of Ni, a soluble salt of Cu, and a soluble salt of Mn in water (e.g., dissolving the soluble salt of Ni, the soluble salt of Cu, and the soluble salt of Mn together (e.g., simultaneously or sequentially in any order) in water, or dissolving them each independently in water and then combining them together) to provide an aqueous solution, then adding a complexing agent, and then adding a base (precipitant) to adjust the pH, for example, to a pH at which co-precipitation of Ni, Cu, and Mn occurs (e.g., effectively occurs); or the aqueous solution, complexing agent, and base (in an amount such that the pH of the resulting mixture is adjusted to a pH at which co-precipitation of Ni, Cu, and Mn occurs (e.g., effectively occurs)) are simultaneously and continuously introduced (e.g., pumped) into a reactor (e.g., a stirred reactor) for reaction.

[0122] For example, the second precursor can be prepared by dissolving a soluble salt of Ni, a soluble salt of Cu, a soluble salt of Mn, and a soluble salt of Ti in water (e.g., dissolving the soluble salt of Ni, the soluble salt of Cu, the soluble salt of Mn, and the soluble salt of Ti together (e.g., simultaneously or sequentially in any order) in water, or dissolving them each independently in water and then combining them together) to provide an aqueous solution, then adding a complexing agent, and then adding a base (precipitant) to adjust the pH, for example, to a pH at which co-precipitation of Ni, Cu, Mn, and Ti occurs (e.g., effectively occurs); or simultaneously and continuously introducing (e.g., pumping) the aqueous solution, complexing agent, and base (in an amount such that the pH of the resulting mixture is adjusted to a pH at which co-precipitation of Ni, Cu, and Mn occurs (e.g., effectively occurs)) into a reactor (e.g., a stirred reactor) for reaction.

[0123] In steps (1-2) and (1-3), the complexing agent (used to prepare the first precursor and the second precursor) is not particularly limited and can be appropriately selected from complexing agents known in the art that can be used to complex Ni, Cu and Mn or Ni, Cu, Mn and Ti. Preferably, the complexing agent does not ultimately introduce other elements other than the elements constituting the layered oxide positive electrode material. For example, the complexing agent can be selected from oxalic acid, ethylenediaminetetraacetic acid (EDTA), urea, citric acid or citrates such as sodium citrate, hydroxycarboxylic acids or salts thereof such as sodium salts, ammonia water, or any combination thereof. The amount of the complexing agent is not particularly limited and can be an amount that effectively forms a complex with these metal ions, which can be appropriately selected according to the type of complexing agent used. For example, in the case of the first precursor, relative to the total molar amount of Ni, Cu and Mn 1 mole, or in the case of the second precursor, relative to the total molar amount of Ni, Cu, Mn and Ti 1 mole, the amount of the complexing agent (such as citric acid or sodium citrate) can be 0.5-3.0 moles, for example, 1.0-2.0 moles, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, or a range limited by any two of them.

[0124] In steps (1-2) and (1-3), the base used for coprecipitation is not particularly limited and can be each independently selected from, for example, sodium hydroxide, sodium carbonate, or any combination thereof.

[0125] In the case of the first precursor and the second precursor, the pH adjusted to by the base can be determined depending on the type of base used (and therefore the type of precipitate formed). For example, when a carbonate is used as the base to form a carbonate precipitate, the pH can be 7.8 or higher, for example, 7.8-8.3, such as 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, or a range defined by any two thereof; when a hydroxide is used as the base to form a hydroxide precipitate, the pH can be 12.5 or higher, for example, 12.5-14.0, such as 12.5, 12.6, 12.7, 12.8, 12.9, 13.0, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.9, 14.0, or a range defined by any two thereof.

[0126] The coprecipitation reaction in steps (1-2) and (1-3) can be carried out at any suitable temperature and is not particularly limited. For example, the coprecipitation reaction can be carried out at a temperature of 25-70° C., for example 35-60° C. (e.g., 25, 30, 35, 40, 45, 50, 55, 60, 65, 70° C., or a range limited by any two thereof).

[0127] In steps (1-2) and (1-3), the sodium source used can be, for example, selected from the sodium sources described above for step (1-1).

[0128] In steps (1-2) and (1-3), the Ni source, Cu source, and Mn source used can be, for example, selected from soluble salts within the ranges described above for each of step (1-1). For example, the Ni source can be one or more selected from the following compounds: nickel nitrate, nickel acetate, nickel oxalate, nickel sulfate, and nickel chloride; the Cu source can be one or more selected from the following compounds: copper nitrate, copper acetate, copper oxalate, copper sulfate, and copper chloride; and the Mn source can be one or more selected from the following compounds: manganese nitrate, manganese acetate, manganese oxalate, manganese sulfate, and manganese chloride.

[0129] In step (1-2), the Ti source used can be, for example, selected from the titanium sources described above for step (1-1). In step (1-3), the Ti source used can be, for example, selected from the soluble Ti sources within the range described above for step (1-1), such as titanium nitrate, titanium oxalate, titanium sulfate, titanyl sulfate, and titanium chloride.

[0130] In a preferred embodiment, the first precursor in step (1-2) and the second precursor in step (1-3) may each independently satisfy one or more, preferably all, of the following conditions, for example 1, 2, 3, 4, 5, 6, or 7:

[0131] Minimum particle size Dmin = 0.05-5 μm, preferably 0.1-2 μm (e.g., 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 μm, or a range defined by any two thereof);

[0132] D10 = 0.1-8 μm, preferably 0.5-5 μm (e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 1.52.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0 μm, or a range defined by any two thereof);

[0133] D50 = 0.2-10 μm, preferably 2-6 μm (e.g., 0.2, 0.3, 0.4, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0 μm, or a range defined by any two thereof);

[0134] D90=2-50 μm, preferably 5-10 μm (e.g., 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, 20.0, 25.0, 30.0, 35.0, 40.0, 45.0, 50.0 μm, or a range defined by any two thereof);

[0135] Maximum particle size Dmax = 2-350 μm, preferably 10-200 μm (e.g., 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 1 25, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300, 310, 315, 320, 325, 330, 335, 340, 345, 350 μm, or a range defined by any two of them);

[0136] BET specific surface area = 5-300m 2 / g, preferably 10-200m 2 / g, preferably 20-75m 2 / g (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140 ,145,150,155,160,165,170,175,180,185,190,195,200,205,210,215,220 ,225,230,235,240,245,250,255,260,265,270,275,280,285,290,295,300m 2 / g, or the range defined by any two of them);

[0137] Tap density = 0.5-3.0g / cm 3 , preferably 1.0-2.5g / cm 3 (e.g., 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0 g / cm 3 , or the range defined by any two of them).

[0138] The mixing in steps (1-1) to (1-3) can be carried out by any suitable mixing method known to those skilled in the art. In one embodiment, the mixing in steps (1-1) to (1-3) is carried out by dry mixing or wet mixing. The wet mixing can be carried out in the presence of any suitable solvent such as water or ethanol.

[0139] Step 2

[0140] In step 2, the precursor mixture obtained in step 1 is sintered once, and then cooled, and optionally crushed and sieved.

[0141] In one embodiment, the primary sintering temperature may be 800-1200°C, preferably 850-1100°C, preferably 850-950°C. For example, in one embodiment, the primary sintering temperature may be 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990, 1000, 1010, 1020, 1030, 1040, 1050, 1060, 1070, 1080, 1090, 1100, 1110, 1120, 1130, 1140, 1150, 1160, 1170, 1180, 1190, 1200°C, or a range defined by any two thereof.

[0142] The time of the primary sintering is not particularly limited and can be 8-30 hours, preferably 10-20 hours. In one embodiment, the sintering time can be, for example, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30 hours, or a range limited by any two thereof.

[0143] The primary sintering can be carried out in a dry oxidizing atmosphere. Preferably, the oxidizing atmosphere is dry compressed air or oxygen. The pressure of the compressed air can be any commonly used pressure, for example, above 0.6 MPa.

[0144] The heating rate during the primary sintering is not particularly limited and can be 1-10°C / min, preferably 2-5°C / min, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10°C / min, or a range defined by any two of the above values.

[0145] After the primary sintering, the product is cooled, optionally crushed and sieved.

[0146] The cooling, crushing and screening can be carried out by any suitable means known to those skilled in the art. For example, crushing and screening can be carried out to obtain particles with a D50 particle size of 2-50 μm, for example, 5-20 μm. For example, the D50 particle size of the particles can be, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 μm, or a range limited by any two thereof.

[0147] Step 3

[0148] In step 3, the product obtained in step 2 is subjected to secondary sintering, cooled, and optionally crushed and sieved to obtain the layered oxide positive electrode material.

[0149] The applicant has found that for a layered oxide positive electrode material having a composition of the elements defined by the invention (Na, Ni, Cu, Mn, Ti, and an optional doping element M), by performing a primary sintering of its precursor mixture and then performing a secondary sintering, the resulting layered oxide positive electrode material can have improved electrochemical properties, especially the first discharge capacity and cycle performance (e.g., discharge capacity) at a higher rate (e.g., 1C). Without being bound by theory, it is believed that this is because, for a raw material (precursor mixture) of a defined composition, by performing a secondary sintering, the resulting particles can have a better morphology and / or crystallographic structure and / or orientation, thereby having better electrochemical performance.

[0150] In one embodiment, the temperature of the secondary sintering may be 800-950° C., preferably 850-950° C. For example, the temperature of the secondary sintering may be 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950° C., or a range defined by any two thereof. When the secondary sintering is performed within the above range, the resulting layered oxide positive electrode material may have better electrochemical properties, particularly the first discharge capacity and cycle performance (e.g., discharge capacity) at a higher rate (e.g., 1C), relative to temperatures outside the range.

[0151] The secondary sintering time is not particularly limited and can be 8-30 hours, preferably 10-20 hours. In one embodiment, the sintering time can be, for example, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30 hours, or a range limited by any two thereof.

[0152] The secondary sintering can be carried out in a dry oxidizing atmosphere. Preferably, the oxidizing atmosphere is dry compressed air or oxygen. The pressure of the compressed air can be any commonly used pressure, for example, above 0.6 MPa.

[0153] The heating rate during the secondary sintering is not particularly limited and can be 1-10°C / min, preferably 2-5°C / min, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10°C / min, or a range defined by any two of the above values.

[0154] After secondary sintering, the product is cooled, optionally crushed and sieved.

[0155] The cooling, pulverizing and screening can be performed by any suitable means known to those skilled in the art.

[0156] All the above descriptions regarding the layered oxide positive electrode material of the first aspect of the present invention are applicable here.

[0157] Positive electrode composition

[0158] The third aspect of the present invention provides a positive electrode composition, which is a positive electrode composition for a sodium ion secondary battery, comprising the layered oxide positive electrode material according to the first aspect of the present invention or the layered oxide positive electrode material prepared by the method of the second aspect of the present invention.

[0159] In addition to the layered oxide cathode material of the present invention, the cathode composition for sodium ion secondary batteries may further include a conductive agent, a binder, and any other substances that can be used by those skilled in the art as needed, such as a dispersant and an additive for improving stability.

[0160] In some embodiments, based on the dry weight of the positive electrode composition for sodium ion secondary batteries, the content of the layered oxide positive electrode material may be a common amount in the art, for example, 70-95 wt %, such as 80-90 wt %.

[0161] The type of conductive agent is not particularly limited, as long as it has the function of enhancing the conductivity of the positive electrode and does not adversely affect the performance of the positive electrode material. Those skilled in the art can select the conductive agent commonly used in the art according to actual needs. As an example, the conductive agent for the positive electrode composition for sodium ion secondary battery can be selected from one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0162] In some embodiments, based on the dry weight of the positive electrode composition for a sodium ion secondary battery, the content of the conductive agent may be a commonly used amount in the art, for example, 1-10 wt %, such as 2-5 wt %.

[0163] The binder is not particularly limited, as long as it has the properties of enhancing the adhesion between the positive electrode active material particles and the adhesion to the current collector and does not adversely affect the performance of the positive electrode material. Those skilled in the art can select according to actual needs. As an example, the binder for the positive electrode composition for the sodium ion secondary battery can be selected from polyfluoroolefin binders such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA) or their modified (for example, carboxylic acid, acrylic acid, acrylonitrile, etc.) derivatives and one or more of styrene-butadiene rubber, acrylic resin, carboxymethyl cellulose, polyvinyl alcohol (PVA), etc.

[0164] In some embodiments, based on the dry weight of the positive electrode composition for a sodium ion secondary battery, the content of the binder is 1-10 wt %, for example, 2-5 wt %.

[0165] The positive electrode composition may be in the form of a slurry, ie, it may further include a solvent. The positive electrode composition may also be in a dry form, ie, it does not include a solvent, for example, it may be in the form of a positive electrode active material layer disposed on a positive electrode current collector.

[0166] Sodium ion secondary batteries

[0167] A fourth aspect of the present invention provides a sodium ion secondary battery. A sodium ion secondary battery generally includes a positive electrode, a negative electrode, a separator, and an electrolyte.

[0168] In some embodiments, the sodium ion secondary battery may further include an outer packaging for encapsulating the electrode assembly and the electrolyte. For example, the outer packaging may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc., or a soft package, such as a bag-type soft package, such as a soft package made of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0169] The shape of the sodium ion secondary battery is not particularly limited, and it may be cylindrical, square, or any other shape.

[0170] Sodium ion secondary batteries can be prepared by methods commonly used in the art. For example, the positive electrode sheet, the negative electrode sheet and the separator can be made into a battery cell through a winding process or a lamination process, and then the electrolyte is injected.

[0171] positive electrode

[0172] The positive electrode (or positive electrode sheet) comprises a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, the positive electrode active material layer comprising the positive electrode active material composition of the third aspect of the present invention, for example in dry form. The positive electrode also forms an aspect of the present invention.

[0173] The positive electrode current collector is not particularly limited, and the positive electrode current collector commonly used by those skilled in the art can be used. As an example, the positive electrode current collector can be made of a metal foil such as aluminum foil, nickel foil, or a composite current collector. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), 1,3-propane sultone (PS), polyethylene (PE), etc.), but the present invention is not limited to these materials.

[0174] The positive electrode sheet can be prepared according to the method commonly used in the art.

[0175] For example, the positive electrode can be formed by uniformly dispersing a positive electrode active material, a conductive agent, and a binder in a solvent (eg, N-methylpyrrolidone (NMP)) to obtain a positive electrode slurry; coating the slurry on a positive electrode current collector, drying, and pressing.

[0176] Alternatively, the positive electrode can also be formed by uniformly dispersing the positive electrode active material, the conductive agent, and the binder in a solvent (e.g., N-methylpyrrolidone (NMP)) to obtain a positive electrode slurry; casting the positive electrode slurry on a separate support, drying, separating the obtained positive electrode film from the support and laminating it on a positive electrode current collector.

[0177] negative electrode

[0178] The negative electrode (or negative electrode plate) can be a metal sodium plate or other commonly used negative electrodes, such as a negative electrode including a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer includes a negative electrode active material.

[0179] The negative electrode current collector is not particularly limited, and the negative electrode current collector commonly used by those skilled in the art can be used. As an example, the negative electrode current collector can be a metal foil such as copper foil, or a composite current collector. The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.), but the present invention is not limited to these materials.

[0180] In some embodiments, the negative electrode active material may be an active material commonly used by those skilled in the art. For example, the negative electrode active material may be one or more of natural graphite, artificial graphite, mesophase microcarbon beads (MCMB), hard carbon, soft carbon, silicon-based materials, tin-based materials, sodium titanate, and metallic sodium. Silicon-based materials may be one or more of elemental silicon, silicon oxides, silicon-carbon composites, and silicon alloys, and tin-based materials may be one or more of elemental tin, tin oxides, and tin alloys.

[0181] In addition to the negative electrode active material, the negative electrode active material layer may further include a binder, a conductive agent, and any other optional auxiliary agents such as a thickener.

[0182] There is no particular requirement for the negative electrode conductive agent. As an example, the conductive agent can be selected from one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0183] In some embodiments, the conductive agent may be present in an amount of 1 to 10 wt %, for example, 2 to 5 wt %, based on the total weight (dry weight) of the negative electrode active material layer.

[0184] There is no particular requirement for the negative electrode binder. As an example, the binder is selected from one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), styrene-butadiene rubber (SBR), water-based acrylic resin and carboxymethyl cellulose (CMC).

[0185] In some embodiments, the binder may be present in an amount of 1 to 10 wt %, for example, 2 to 5 wt %, based on the total weight (dry weight) of the negative electrode active material layer.

[0186] The negative electrode can be prepared according to a method commonly used in the art.

[0187] For example, the negative electrode can be formed by uniformly dispersing the negative electrode active material and optional conductive agent, binder and thickener in a solvent (such as N-methylpyrrolidone (NMP) or deionized water) to form a negative electrode slurry; coating the negative electrode slurry on a negative electrode current collector, drying, and pressing.

[0188] Alternatively, the negative electrode can also be formed by uniformly dispersing the negative electrode active material and optional conductive agent, binder and thickener in a solvent (such as N-methylpyrrolidone (NMP) or deionized water) to form a negative electrode slurry; casting the negative electrode slurry on a separate support, drying, separating the obtained negative electrode film from the support and laminating it on a negative electrode current collector.

[0189] electrolytes

[0190] The electrolyte conducts ions between the positive and negative electrodes. The electrolyte is not particularly limited and can be selected based on needs. For example, the electrolyte can be selected from at least one of a solid electrolyte, a gel electrolyte, and a liquid electrolyte (i.e., an electrolyte solution).

[0191] In some embodiments, the electrolyte is an electrolyte solution comprising an organic aprotic solvent and an electrolyte sodium salt.

[0192] In some embodiments, the solvent can be selected from one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS) and diethyl sulfone (ESE).

[0193] In some embodiments, the electrolyte sodium salt can be selected from one or more of sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroborate (NaBF6), sodium bis(trifluoromethylsulfonyl)imide (NaFSI), sodium bis(trifluoromethylsulfonyl)imide (NaTFSI), sodium trifluoromethylsulfonate (NaTFS), sodium difluorooxalatoborate (NaDFOB), sodium dioxalatoborate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorobis(oxalatophosphate) (NaDFOP) and sodium tetrafluorooxalatophosphate (NaTFOP).

[0194] In some embodiments, the concentration of sodium ions in the electrolyte may be 0.2 to 2 mol / L, for example, 0.5-1.0 mol / L.

[0195] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include additives that facilitate negative electrode film formation or positive electrode film formation, or additives that improve battery performance, such as additives that improve high or low temperature performance of the battery.

[0196] diaphragm

[0197] The separator is not particularly limited, and a commonly used porous structure separator with electrochemical stability and chemical stability can be used. For example, it can be a single layer or multilayer film of one or more of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. When a solid electrolyte is used, the separator can also be omitted.

[0198] use

[0199] The fifth aspect of the present invention provides the use of the sodium ion secondary battery according to the fourth aspect of the present invention in an energy storage device, especially an energy storage device for solar power generation, wind power generation, smart grid peak regulation, distributed power station, backup power supply or communication base station.

[0200] Those skilled in the art will appreciate that the sodium ion secondary battery of the fourth aspect of the present invention may also be used for other purposes. For example, the sodium ion secondary battery may be used as a power source or energy storage unit in mobile devices (e.g., mobile phones), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, electric bicycles, electric scooters, etc.), electric trains, etc.

[0201] Example

[0202] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0203] 1. Test Method

[0204] 1. Particle size D10, D50, D90, D min and D max

[0205] The test was conducted using a Malvern 3000 laser particle size analyzer, using lithium cobalt oxide as the standard material and water as the dispersant. The instrument parameters were set as follows: test time 10 seconds, test number 3, shading 6-15%, stirring speed 2800 rpm, ultrasonic mode on, power 50%. The laser particle size analyzer (Malvern 3000 laser particle size analyzer) was clicked to start the test. The layered oxide cathode material was then added to the sample cell, adjusting the amount of material added to adjust the shading to 6-15%. The instrument automatically repeated the test three times, and the average of the three tests was used as the test result.

[0206] 2.BET surface area

[0207] The test was performed with reference to GB / T 19587-2017, "Determination of the Specific Surface Area of ​​Solid Substances by the BET Method for Gas Adsorption." The layered oxide cathode material (30-500 mg) was placed in a sample tube and degassed. After degassing, the heating power was turned off. After the sample cooled to room temperature, helium was backfilled and the sample tube was weighed. The weighed sample tube was placed in a BET surface area analyzer (Jingwei Gaobo JW-DX) and the sample mass was entered into the analysis file. Click the instrument to begin the adsorption and desorption test process. The results were automatically output after the test.

[0208] 3. Tap density

[0209] Weigh 25g of the layered oxide cathode material into a standard graduated cylinder (50ml, 22mm inner diameter). Vibrate the cylinder using a vibrator. Set the vibrator to a stroke of 3mm, a frequency of 100 vibrations / min, and a duration of 30 minutes. Read the volume of the cathode material in the cylinder after vibration. Divide the powder mass by the volume to obtain the tap density.

[0210] 4. pH

[0211] An appropriate amount of the layered oxide cathode material was added to a corresponding amount of distilled water at a mass ratio of 1:20. The mixture was then magnetically stirred at 600 ± 20 rpm for 10 minutes to ensure uniform mixing. The resulting mixture was then allowed to stand for 5 minutes. The pH of the mixture was then measured at 25°C using a METTLER TOLEDO pH meter FE22-Standard. This pH represents the pH of the corresponding material.

[0212] 5.XRD diffraction

[0213] Take the layered oxide positive electrode material and place it in a carrier. Set the X-ray diffractometer (Bruker X-ray diffractometer D8 ADVANCE) to a scanning angle of 10° to 80° and a scanning speed of 5° / min. Obtain the XRD spectrum of the layered oxide positive electrode material. Use the data processing software Jade 6.0 to perform data smoothing, background subtraction, peak search, phase retrieval, characteristic peak marking, and read characteristic peak information. In the embodiment of the present invention, the peak intensity ratio of two diffraction peaks represents the ratio of the peak areas of the corresponding diffraction peaks in the XRD spectrum.

[0214] 6. Scanning Electron Microscopy (SEM)

[0215] The test was performed using a HITACHI (S-4800) scanning electron microscope with an accelerating voltage of 10 kV and a magnification of 10K, and general morphology was captured.

[0216] 7. Electrochemical performance test

[0217] Production of button cells: The sintered products prepared in each example were used as active materials in a dry room (dew point -30°C, relative humidity below 10%) to prepare positive electrode sheets. Specifically, 0.45g of active material, 0.025g of SP (Swiss Terme high conductive carbon black SUPER P), and 0.25g of polyvinylidene fluoride (PVDF, purchased from SOLVAY PVDF5130) glue (10% by mass, solvent N-methylpyrrolidone (NMP)) were uniformly mixed, and then N-methylpyrrolidone was added to form a viscous glue. The glue was coated on aluminum foil (thickness 16μm) and then baked in a vacuum drying oven at 120°C for 12 hours to obtain a positive electrode sheet with a coating thickness of 150 microns. A metal sodium sheet (Aladdin) was used as the counter electrode (thickness 300±50μm). CR2032 button cells were assembled in an Ar atmosphere protective glove box using glass fiber (Waterman) as the separator (thickness 675 μm) and NaPF6 solution with a sodium ion concentration of 1 mol / L (the solvent was a mixture of EC and DMC, with a volume ratio of EC / DMC = 1:1) (Alfa) as the electrolyte.

[0218] After the CR2032 button cell is assembled, charge the button cell at 25°C at a constant current of 0.1C to 4.3V, then let it rest for 30s. Record the charge capacity as the first charge capacity C0. Then discharge it at a constant current of 0.1C to 2.0V, record the discharge capacity as the first discharge capacity D0, and repeat this 0.1C charge and 0.1C discharge cycle three times. The 0.1C first discharge capacity D0 / 0.1C first charge capacity C0×100% is the 0.1C first coulombic efficiency (also known as the first efficiency). In the embodiment, 1C=100mA / g, that is, the current density of 0.1C is 10mA / g.

[0219] The battery was then charged at a constant current of 0.5C to 4.3V, allowed to rest for 30 seconds, and then discharged at a constant current of 0.5C to 2.0V. This 0.5C charge-0.5C discharge cycle was repeated three times. The initial discharge capacity at 0.5C was taken as the initial discharge capacity at 0.5C, and divided by D0 to obtain the ratio of initial discharge capacity at 0.5C to initial discharge capacity at 0.1C.

[0220] Then charge at a constant current of 1C to 4.3V, let it rest for 30 seconds, and then discharge at a constant current of 1C to 2.0V. Repeat this 1C charge-1C discharge cycle 100 times. The first discharge capacity at 1C is taken as the 1C first discharge capacity, and divided by D0 to obtain the ratio of 1C first discharge capacity / 0.1C first discharge capacity. The 100th 1C discharge capacity divided by the 1C first discharge capacity is the capacity retention rate after 100 cycles of 1C.

[0221] At the end of each charging and discharging process, the device was left to stand for 30 seconds before starting the next process.

[0222] 2. Example: Preparation of O3-phase layered oxide positive electrode material

[0223] Example 1A: Na 0.75 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.875 preparation

[0224] Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of precursor 1: nickel sulfate, copper sulfate, manganese sulfate, and titanium oxysulfate were weighed according to the stoichiometric ratio of 4:1:4:1, and dissolved in deionized water to prepare a sulfate mixed solution with a total concentration of 2 mol / L, and the mixed solution, 0.6 mol / L sodium citrate aqueous solution, and 2 mol / L sodium carbonate aqueous solution were continuously pumped into another reactor with a water bath jacket, and the reactor was stirred at the same time, wherein the temperature of the solution in the reactor was maintained at 55°C, the sodium citrate / (nickel + copper + manganese + titanium) molar ratio was 1:1, and the sodium carbonate aqueous solution controlled the pH of the obtained solution in the reactor to 7.8, and obtained a precipitate with a particle size D50 of 5.165 μm, and the obtained precipitate was separated by suction filtration and washed with water, and then dried at 80°C for 2h, and then sintered at 700°C for 10h to obtain Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Precursor 1. The physicochemical properties of Precursor 1 are shown in Table 1 below.

[0225] Na 0.75 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2: Sodium carbonate and precursor 1 were weighed according to the stoichiometric ratio, mixed evenly, and then sintered at 950 ° C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. Then, the mixture was cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 7.749 μm. 0.75 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.875 .

[0226] Example 1B: Na 0.75 Ni0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.875 Preparation

[0227] The primary sintered product prepared in Example 1A was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 7.861 μm. 0.75 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.875 .

[0228] Example 2A: Na 0.8 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.9 Preparation

[0229] Sodium carbonate and the precursor 1 prepared in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 8.032 μm. 0.8 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.9 .

[0230] Example 2B: Na 0.8 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.9 Preparation

[0231] The primary sintered product prepared in Example 2A was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 8.534 μm. 0.8 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.9 .

[0232] Example 3A: Na0.85 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.925 Preparation

[0233] Sodium carbonate and the precursor 1 prepared in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 900°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 6.936 μm. 0.85 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.925 .

[0234] Example 3B: Na 0.85 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.925 Preparation

[0235] The primary sintered product prepared in Example 3A was sintered at 900°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 7.409 μm. 0.85 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.925 .

[0236] Example 4A: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0237] Sodium carbonate and the precursor 1 prepared in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 850°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 5.36 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0238] Example 4B: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0239] The primary sintered product prepared in Example 4A was sintered at 850°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 8.139 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0240] Example 4C: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0241] Sodium carbonate and the precursor 1 prepared in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 10.62 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0242] Example 4D: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0243] The primary sintered product prepared in Example 4C was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 10.96 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O1.95 .

[0244] Example 4E: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0245] Sodium carbonate and the precursor 1 prepared in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 1000°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 12.95 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0246] Example 4F: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0247] The primary sintered product prepared in Example 4E was sintered at 1000°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 16.31 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0248] Example 5A: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0249] Ni 0.4 Cu 0.1 Mn 0.4Preparation of precursor 2: Nickel sulfate, copper sulfate, and manganese sulfate were weighed according to the stoichiometric ratio of 4:1:4, and dissolved in deionized water to prepare a sulfate mixed solution with a total concentration of 2 mol / L, and the mixed solution, 0.6 mol / L sodium citrate aqueous solution, and 2 mol / L sodium carbonate aqueous solution were continuously pumped into another reactor with a water bath jacket, and the reactor was stirred at the same time, wherein the temperature of the solution in the reactor was maintained at 55°C, the sodium citrate / (nickel + copper + manganese) molar ratio was 1:1, and the sodium carbonate aqueous solution was used to control the pH of the solution in the reactor to 7.8, and a precipitate with a particle size D50 of 4.291 μm was obtained. The obtained precipitate was separated by suction filtration and washed with water, and then dried at 80°C for 2 h, and then sintered at 700°C for 10 h to obtain Ni 0.4 Cu 0.1 Mn 0.4 Precursor 2. The physicochemical properties of Precursor 2 are shown in Table 1 below.

[0250] Sodium carbonate, precursor 2, and titanium dioxide (particle size D50 = 0.5 μm) were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 10.15 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0251] Example 5B: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0252] The primary sintered product prepared in Example 5A was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 12.7 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0253] Example 6A: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4Ti 0.1 O 1.95 Preparation

[0254] Sodium carbonate, precursor 2, and titanium dioxide (particle size D50 = 3.5 μm) were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 10.21 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0255] Example 6B: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0256] The primary sintered product prepared in Example 6A was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 11.25 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0257] Example 7A: Na 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0258] Sodium carbonate and precursor 1 were weighed according to the stoichiometric ratio, mixed evenly, and then sintered at 900 ° C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 7.152 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0259] Example 7B: Na 0.9 Ni 0.4Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0260] The primary sintered product prepared in Example 7A was sintered at 900°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 8.164 μm. 0.9 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.95 .

[0261] Example 8: Na 0.9 Ni 0.35 Cu 0.05 Mn 0.45 Ti 0.15 O 2.05 Preparation

[0262] Sodium carbonate, copper oxide, nickel oxide (NiO), manganese dioxide and titanium dioxide were weighed according to the stoichiometric ratio and uniformly mixed. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a primary sintered product with a D50 of 11.02 μm. The primary sintered product was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a secondary sintered product Na with a D50 of 11.58 μm. 0.9 Ni 0.35 Cu 0.05 Mn 0.45 Ti 0.15 O 2.05 .

[0263] Example 9: Na 0.9 Ni 0.45 Cu 0.15 Mn 0.35 Ti 0.05 O 1.85 Preparation

[0264] Sodium carbonate, copper oxide, nickel oxide (NiO), manganese dioxide and titanium dioxide were weighed according to the stoichiometric ratio and uniformly mixed. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a primary sintered product with a D50 of 10.04 μm. The primary sintered product was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a secondary sintered product Na with a D50 of 11.18 μm. 0.9 Ni 0.45 Cu 0.15 Mn 0.35 Ti 0.05 O 1.85 .

[0265] Example 10: Na 0.9 Ni 0.35 Cu 0.15 Mn 0.45 Ti 0.05 O 1.95 Preparation

[0266] Sodium carbonate, copper oxide, nickel oxide (NiO), manganese dioxide and titanium dioxide were weighed according to the stoichiometric ratio and uniformly mixed. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a primary sintered product with a D50 of 10.87 μm. The primary sintered product was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a secondary sintered product Na with a D50 of 11.41 μm. 0.9 Ni 0.35 Cu 0.15 Mn 0.45 Ti 0.05 O 1.95 .

[0267] Example 11: Na 0.9 Ni 0.35 Cu 0.15 Mn 0.35 Ti 0.15 O 1.95 Preparation

[0268] Sodium carbonate, copper oxide, nickel oxide (NiO), manganese dioxide and titanium dioxide were weighed according to the stoichiometric ratio and uniformly mixed. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a primary sintered product with a D50 of 9.32 μm. The primary sintered product was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a secondary sintered product Na with a D50 of 11.17 μm. 0.9 Ni 0.35 Cu 0.15 Mn 0.35 Ti 0.15 O 1.95 .

[0269] Example 12: Na 0.9 Ni 0.45 Cu 0.05 Mn 0.4 Ti 0.1 O 1.95 Preparation

[0270] Sodium carbonate, copper oxide, nickel oxide (NiO), manganese dioxide and titanium dioxide were weighed according to the stoichiometric ratio and uniformly mixed. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a primary sintered product with a D50 of 5.362 μm. The primary sintered product was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a secondary sintered product Na with a D50 of 5.493 μm. 0.9 Ni 0.45 Cu 0.05 Mn 0.4 Ti 0.1 O 1.95 .

[0271] Example 13: Na 0.9 Ni 0.35 Cu 0.1 Mn 0.35 Ti 0.1 Fe 0.1 O 1.95 Preparation

[0272] Sodium carbonate, copper oxide, nickel oxide (NiO), iron oxide (Fe2O3), manganese dioxide and titanium dioxide were weighed according to the stoichiometric ratio, uniformly mixed, and then sintered at a temperature of 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 hours, and then cooled, crushed and sieved to obtain a primary sintered product with a D50 of 7.315 μm. The primary sintered product was sintered at a temperature of 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 hours, and then cooled, crushed and sieved to obtain a secondary sintered product Na with a D50 of 7.627 μm. 0.9 Cu 0.1 Ni 0.35 Fe 0.1 Mn 0.35 Ti 0.1 O 1.95 .

[0273] Example 14A: Na 0.92 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.96 Preparation

[0274] Sodium carbonate and the precursor 1 synthesized in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 12.13 μm. 0.92 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.96 .

[0275] Example 14B: Na 0.92 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.96 Preparation

[0276] The primary sintered product prepared in Example 14A was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 16.17 μm. 0.92 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O1.96 .

[0277] Example 15A: Na 0.95 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 Preparation

[0278] Sodium carbonate and the precursor 1 synthesized in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 11.362 μm. 0.95 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 .

[0279] Example 15B: Na 0.95 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 Preparation

[0280] The primary sintered product prepared in Example 16A was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 16.7 μm. 0.95 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 .

[0281] Example 16A: Na 0.95 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 Preparation

[0282] Sodium carbonate and the precursor 1 synthesized in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 1000°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 14.28 μm. 0.95 Ni 0.4 Cu0.1 Mn 0.4 Ti 0.1 O 1.975 .

[0283] Example 16B: Na 0.95 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 Preparation

[0284] The primary sintered product prepared in Example 16A was sintered at 1000°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 18.66 μm. 0.95 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 .

[0285] Example 17A: Na 0.95 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 Preparation

[0286] Sodium carbonate and the precursor 1 synthesized in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 900°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 6.876 μm. 0.95 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 .

[0287] Example 17B: Na 0.95 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 Preparation

[0288] The primary sintered product 17A prepared in Example 17A was sintered at 900°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 6.952 μm. 0.95Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O 1.975 .

[0289] Example 18A: Na 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2

[0290] Sodium carbonate and the precursor 1 prepared in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 1000°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 15.17 μm. 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O2.

[0291] Example 18B: Na 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2

[0292] The primary sintered product prepared in Example 18A was sintered at 1000°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 19.19 μm. 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O2.

[0293] Example 19A: Na 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2

[0294] Sodium carbonate and the precursor 1 prepared in Example 1A were weighed according to the stoichiometric ratio and mixed evenly. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 11.5 μm. 1.0 Ni 0.4 Cu0.1 Mn 0.4 Ti 0.1 O2.

[0295] Example 19B: Na 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2

[0296] The primary sintered product prepared in Example 19A was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 11.05 μm. 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O2.

[0297] Example 20A: Na 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2

[0298] Sodium carbonate, copper oxide, nickel oxide (NiO), manganese dioxide and titanium dioxide were weighed according to the stoichiometric ratio, uniformly mixed, and then sintered at 950 ° C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, and then cooled, crushed and sieved to obtain a primary sintered product Na with a D50 of 11.75 μm. 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O2.

[0299] Example 20B: Na 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2

[0300] The primary sintered product prepared in Example 20A was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 14.54 μm. 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O2.

[0301] Example 21A: Na 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2

[0302] Sodium carbonate, the precursor 2 prepared in Example 5A, and titanium dioxide (particle size D50 = 0.5 μm) were weighed according to the stoichiometric ratio and mixed uniformly. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 11.96 μm. 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O2.

[0303] Example 21B: Na 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2

[0304] The primary sintered product prepared in Example 21A was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 14.23 μm. 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O2.

[0305] Example 22A: Na 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2

[0306] Sodium carbonate, the precursor 2 prepared in Example 5A, and titanium dioxide (particle size D50 = 3.5 μm) were weighed according to the stoichiometric ratio and mixed uniformly. The mixture was then sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h. The mixture was then cooled, crushed, and sieved to obtain a primary sintered product Na with a D50 of 11.07 μm. 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O2.

[0307] Example 22B: Na 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 Preparation of O2

[0308] The primary sintered product prepared in Example 22A was sintered at 950°C in an oxygen atmosphere (pressure 0.15 MPa, flow rate 30 L / min) for 15 h, then cooled, crushed, and sieved to obtain a secondary sintered product Na with a D50 of 13.1 μm. 1.0 Ni 0.4 Cu 0.1 Mn 0.4 Ti 0.1 O2.

[0309] Table 1: Properties of synthesized precursors 1 and 2

[0310] Figures 1-2 show scanning electron microscope photographs of the sintered products prepared in Examples 4A-4B at a magnification of 10,000, respectively; Figures 3-4 show scanning electron microscope photographs of the sintered products prepared in Examples 5A-5B at a magnification of 10,000, respectively; Figures 5-6 show scanning electron microscope photographs of the sintered products prepared in Examples 6A-6B at a magnification of 10,000, respectively; Figures 7-8 show scanning electron microscope photographs of the sintered products prepared in Examples 7A-7B at a magnification of 10,000, respectively.

[0311] As can be seen from Figures 1-8, after the primary sintering product is subjected to secondary sintering, the surface morphology of the product particles changes, the particle morphology becomes more regular, the plate-like morphology becomes less obvious, and the particle edges become blunt and rounded.

[0312] The properties of the products prepared in Examples 1A-22B are shown in Tables 2-5 below, where Table 2 shows the particle size, specific surface area, tap density and pH properties of the products prepared in Examples 1A-22B and the active material surface density of the positive electrode sheets prepared therefrom, Table 3 shows the XRD properties of the products prepared in Examples 1A-22B, and Tables 4-5 show the electrochemical properties of the products prepared in Examples 1A-17B and 18A-22B, respectively.

[0313] Table 2: Particle size, specific surface area, tap density, pH, and surface density of active materials in the electrode of the products of Examples 1A-22B

[0314] Table 3: XRD properties of the products of Examples 1A-22B

[0315] It can be seen from Table 3 that by controlling the composition of the product and changing the sintering conditions (including whether to perform secondary sintering and the sintering temperature), the obtained products have different XRD diffraction patterns.

[0316] It can be seen from Tables 4-5 that by controlling the composition of the product and changing the sintering conditions, the obtained products have different electrochemical properties: within the composition range defined by the present invention, Examples 1B, 2B, 3B, 4B, 4D, 5B, 6B, 7B, 14B, 15B, and 17B that undergo secondary sintering have significantly better electrochemical properties than Examples 1A, 2A, 3A, 4A, 4C, 5A, 6A, 7A, 14A, 15A, and 17A that do not undergo secondary sintering, respectively, in particular, in terms of cycle performance (e.g., 1C 100-cycle discharge specific capacity) at higher rates (e.g., 1C); and the electrochemical performance is also significantly better than that of Examples not having the composition range defined by the present invention (e.g., Examples 18A-22B). And for Examples 18A-22B that do not have the composition within the scope defined by the present invention, it can be seen from the comparison between Examples 18A and 18B, 19A and 19B, 20A and 20B, 21A and 21B, and 22A and 22B that secondary sintering does not lead to better electrochemical performance, especially the cycling performance at higher rates (e.g., 1C) (e.g., 1C 100-cycle discharge specific capacity).

[0317] Without being bound by any theory, this is believed to be because: within the material composition range defined in the present invention, after the first calcination, the second calcination can improve the crystallographic structure and / or orientation and / or morphology of the resulting product, so that it has a specific XRD diffraction pattern, especially a specific peak intensity ratio between specific diffraction peaks, thereby the resulting layered oxide positive electrode material can have improved electrochemical properties, especially the first discharge capacity and cycle performance (such as discharge capacity) at a higher rate (such as 1C).

[0318] The above description is merely an exemplary embodiment of the present invention. It should be noted that, for those skilled in the art, improvements can be made to the present invention without departing from the inventive concept of the present invention, and these improvements all fall within the scope of protection of the present invention.

Claims

1. A layered oxide cathode material having the following general formula: Na a Ni b Cu c Mn d Ti e M f O g , in: M is one or more elements selected from Li, Fe, B, Mg, Al, Si, Ca, Zr, Zn, Ta, Mo, W, La, Sr, Sb, Ce, Nb, Sn, and Y; a＝0.75-0.95； b＝0.33-0.45； c＝0.03-0.15； d＝0.20-0.45； e＝0.05-0.20； f＝0-0.1； and g＝1.80-2.20； And in the XRD diffraction pattern of the layered oxide positive electrode material, The peak intensity ratio of (101) crystal plane to (003) crystal plane I (101) / I (003) =0.02-0.15; Peak intensity ratio of (101) crystal plane to (012) crystal plane I (101) / I (012) =0.35-0.47; and Peak intensity ratio of (101) crystal plane to (006) crystal plane I (101) / I (006) =0.08-0.

57. 2 . The layered oxide positive electrode material according to claim 1 , wherein a=0.85-0.

92. The layered oxide positive electrode material according to claim 1 , wherein a=0.90-0.

92. The layered oxide positive electrode material according to claim 1 , wherein b=0.35-0.

45. The layered oxide positive electrode material according to claim 1 , wherein b=0.35-0.

40. The layered oxide positive electrode material according to claim 1 , wherein c=0.05-0.

15. The layered oxide positive electrode material according to claim 1 , wherein c=0.10-0.

15. The layered oxide positive electrode material according to claim 1 , wherein d=0.35-0.

45. 9 . The layered oxide positive electrode material according to claim 1 , wherein d=0.35-0.

40. 10 . The layered oxide positive electrode material according to claim 1 , wherein e=0.05-0.

15. The layered oxide positive electrode material according to claim 1 , wherein e=0.10-0.

15.

12. The layered oxide cathode material according to claim 1, wherein (101) / I (003) =0.02-0.14, I (101) / I (012) =0.35-0.45, and I (101) / I (006) =0.08-0.

55.

13. The layered oxide cathode material according to claim 1, wherein (101) / I (003) =0.02-0.14, I (101) / I (012) =0.38-0.43, and I (101) / I (006) =0.08-0.

55.

14. The layered oxide cathode material according to claim 1, wherein the XRD diffraction peaks of the layered oxide cathode material further satisfy any one, two or all three of the following conditions: a peak intensity ratio of the (006) crystal plane to the (003) crystal plane of 1 (006) / I (003) =0.13-0.27; Peak intensity ratio of (101) crystal plane to (104) crystal plane I (101) / I (104) =0.08-0.12; Peak intensity ratio of (012) crystal plane to (104) crystal plane I (012) / I (104) =0.21-0.

29.

15. The layered oxide cathode material according to claim 14, wherein (006) / I (003) =0.16-0.27, I (101) / I (104) =0.09-0.12, I (012) / I (104) =0.22-0.

28.

16. The layered oxide cathode material according to claim 14, wherein (006) / I (003) =0.18-0.27, I (101) / I (104) =0.09-0.11, I (012) / I (104) =0.24-0.

27.

17. The layered oxide cathode material according to claim 14, wherein (006) / I (003) =0.18-0.27, I (101) / I (104) =0.10-0.11, I (012) / I (104) =0.24-0.

26.

18. The layered oxide cathode material according to any one of claims 1 to 17, wherein the XRD diffraction peaks of the layered oxide cathode material further satisfy any one, two, three or all four of the following conditions: a peak intensity ratio of the (012) crystal plane to the (003) crystal plane of 1: (012) / I (003) =0.05-0.36; Peak intensity ratio of (104) crystal plane to (003) crystal plane I (104) / I (003) =0.19-1.46; Peak intensity ratio of (006) crystal plane to (104) crystal plane I (006) / I (104) =0.19-1.24; Peak intensity ratio of (006) crystal plane to (012) crystal plane I (006) / I (012) =0.76-5.

02.

19. The layered oxide positive electrode material according to any one of claims 1 to 17, wherein: b+c=0.40-0.60; and d+e=0.40-0.

60.

20. The layered oxide cathode material according to claim 19, wherein: b+c=0.45-0.55; and d+e=0.40-0.

55.

21. The layered oxide cathode material according to any one of claims 1 to 17, further satisfying any one, two, three, four, or all five of the following conditions: particle size D10 = 1-15 μm; particle size D50 = 2-35 μm; particle size D90 = 5-70 μm; (D90-D10) / D50 ≤ 2.0; BET specific surface area = 0.1-1.5 m 2 / g.

22. The layered oxide cathode material according to claim 21, wherein: Particle size D10 = 2-8 μm; Particle size D50 = 5-20 μm; Particle size D90 = 10-35 μm; (D90-D10) / D50=1.0-1.8; BET specific surface area=0.2-0.8m 2 / g.

23. The layered oxide cathode material according to claim 22, wherein: (D90-D10) / D50=1.2-1.

7. 24 . The layered oxide positive electrode material according to claim 1 , wherein the layered oxide positive electrode material belongs to the R-3m space group and has an O 3 phase crystal structure.

25. A method for preparing the layered oxide positive electrode material according to any one of claims 1 to 24, comprising the following steps: Step 1: (1-1) mixing a Na source, a Cu source, a Mn source, a Ni source, a Ti source, and an optional M source in a stoichiometric ratio to obtain a precursor mixture; or (1-2) synthesizing a first precursor containing Ni, Cu, and Mn by coprecipitating Ni, Cu, and Mn, and mixing a Na source, a first precursor, a Ti source, and an optional M source in a stoichiometric ratio to obtain a precursor mixture; or (1-3) synthesizing a second precursor containing Ni, Cu, Mn, and Ti by coprecipitating Ni, Cu, Mn, and Ti, and mixing a Na source, the second precursor, and an optional M source in a stoichiometric ratio to obtain a precursor mixture; and Step 2: sintering the precursor mixture obtained in step 1, cooling it, and optionally crushing and sieving it; Step 3: The product obtained in step 2 is subjected to secondary sintering, cooling, and optionally crushing and sieving to obtain the layered oxide positive electrode material.

26. The method according to claim 25, wherein the primary sintering is carried out at a temperature of 800-1200°C and the primary sintering time is 8-30 hours.

27. The method according to claim 26, wherein the primary sintering is carried out at a temperature of 850-1100°C and the primary sintering time is 10-20 hours.

28. The method according to claim 26, wherein the primary sintering is performed at a temperature of 850-950°C.

29. The method according to any one of claims 25 to 28, wherein the secondary sintering is carried out at a temperature of 800-950°C and a secondary sintering time of 8-30 hours.

30. The method according to claim 29, wherein the secondary sintering is performed at a temperature of 850-950°C and the secondary sintering time is 10-20 hours.

31. The method according to any one of claims 25 to 28, wherein the first precursor and the second precursor each independently satisfy any one, two, three, four, five, six, or all seven of the following conditions: minimum particle size Dmin = 0.05-5 μm; particle size D10 = 0.1-8 μm; particle size D50 = 0.2-10 μm; particle size D90 = 2-50 μm; maximum particle size Dmax = 2-350 μm; BET specific surface area = 5-300 m 2 / g; tap density = 0.5-3.0g / cm 3 .

32. The method according to any one of claims 25 to 28, wherein the first precursor and the second precursor each independently satisfy any one, two, three, four, five, six, or all seven of the following conditions: minimum particle size Dmin = 0.1-2 μm; particle size D10 = 0.5-5 μm; particle size D50 = 2-6 μm; particle size D90 = 5-10 μm; maximum particle size Dmax = 10-200 μm; BET specific surface area = 10-200 m 2 / g; tap density = 1.0-2.5g / cm 3 .

33. The method according to claim 32, wherein the first precursor and the second precursor each have a BET specific surface area of ​​20-75 m 2 / g.

34. The method according to any one of claims 25 to 28, wherein For step (1-1): The Na source is one or more compounds selected from the following: sodium carbonate, sodium bicarbonate, sodium nitrate, sodium acetate, sodium oxalate, sodium hydroxide, sodium chloride, sodium sulfate and sodium oxide; The Ni source is one or more compounds selected from the group consisting of nickel carbonate, nickel nitrate, nickel acetate, nickel oxalate, nickel hydroxide, nickel sulfate, nickel chloride and nickel oxide; The Cu source is one or more compounds selected from the group consisting of copper carbonate, copper nitrate, copper acetate, copper oxalate, copper hydroxide, copper sulfate, copper chloride and copper oxide; The Mn source is one or more compounds selected from the group consisting of manganese carbonate, manganese nitrate, manganese acetate, manganese oxalate, manganese hydroxide, manganese sulfate, manganese chloride and manganese oxide; The Ti source is one or more compounds selected from the group consisting of titanium nitrate, titanium oxalate, titanium hydroxide, titanium sulfate, titanyl sulfate, titanium chloride, and titanium oxide; and The M source is one or more compounds selected from the group consisting of carbonates, nitrates, acetates, oxalates, hydroxides, sulfates, chlorides, and oxides; For steps (1-2) and (1-3): The Na source is one or more compounds selected from the following: sodium carbonate, sodium bicarbonate, sodium nitrate, sodium acetate, sodium oxalate, sodium hydroxide, sodium chloride and sodium oxide; The Ni source is one or more compounds selected from the group consisting of nickel nitrate, nickel acetate, nickel oxalate, nickel sulfate, and nickel chloride; The Cu source is one or more compounds selected from the following: copper nitrate, copper acetate, copper oxalate, copper sulfate, copper chloride; The Mn source is one or more compounds selected from the group consisting of manganese nitrate, manganese acetate, manganese oxalate, manganese sulfate, and manganese chloride; The Ti source is one or more compounds selected from the group consisting of titanium nitrate, titanium oxalate, titanium sulfate, titanyl sulfate, and titanium chloride; and The source of M is one or more compounds selected from the group consisting of carbonates, nitrates, acetates, oxalates, hydroxides, chlorides, and oxides.

35. The method according to any one of claims 25 to 28, wherein the primary sintering and the secondary sintering are each independently performed in a dry oxidizing atmosphere.

36. The method of claim 35, wherein the oxidizing atmosphere is compressed air or oxygen.

37. The method according to claim 25, wherein the product obtained in step 2 has a D50 particle size of 2-50 μm.

38. The method according to claim 37, wherein the product obtained in step 2 has a D50 particle size of 5-20 μm.

39. A positive electrode composition for a sodium ion secondary battery, comprising the layered oxide positive electrode material according to any one of claims 1 to 24.

40. A sodium ion secondary battery comprising the positive electrode composition according to claim 39.

41. Use of the sodium ion secondary battery according to claim 40 in energy storage equipment for solar power generation, wind power generation, smart grid peak regulation, distributed power stations, backup power supplies or communication base stations.

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