CN117133912A

CN117133912A - Sodium ion layered oxide positive electrode material, positive electrode plate, battery and electricity utilization device

Info

Publication number: CN117133912A
Application number: CN202311399969.6A
Authority: CN
Inventors: 林敏�; 栾柯; 徐波; 欧阳楚英
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2023-10-26
Filing date: 2023-10-26
Publication date: 2023-11-28

Abstract

The application belongs to the technical field of batteries, and particularly relates to a sodium ion layered oxide positive electrode material, a positive electrode plate, a battery and an electric device. The sodium ion layered oxide positive electrode material comprises Na _x Ni _a Fe _b Mn _c M ¹ _d M ² _e O _2‑p A _p ，0.6<x<1.2，0≤a，0≤b，0≤c，0≤d，0<e≤0.15，a+b+c+d+e=1，0<（a+b）/(c+d+e)≤19，0≤pLess than or equal to 0.1; the M is ¹ Comprises one or more elements from IA to VA groups and IB to VIIB groups, wherein M is ² Comprises one or more elements of Ga and Ta, wherein the A comprises one or more nonmetallic elements of VIA groups and VIIA groups. According to the application, the water stability of the sodium ion layered oxide anode material can be enhanced by doping one or more elements of Ga and Ta.

Description

Sodium ion layered oxide positive electrode material, positive electrode plate, battery and electricity utilization device

Technical Field

The application belongs to the technical field of batteries, and particularly relates to a sodium ion layered oxide positive electrode material, a positive electrode plate, a battery and an electric device.

Background

Sodium ion batteries are widely distributed due to the fact that raw materials are abundant in nature, so that the sodium ion batteries are widely focused and studied.

The positive electrode material is a key factor for realizing the performances of high capacity, high voltage, long cycle life and the like of the sodium ion battery. The sodium ion battery collection materials which are studied more at present comprise layered oxides, polyanions, prussian blue analogues and the like. Among them, nickel-iron-manganese-based layered oxides in layered oxide cathode materials are one of the hot spots of research because they exhibit higher specific capacity, excellent performance, and simple synthesis than other cathode materials. However, the layered oxide has a problem of poor water stability, which affects the development of sodium ion batteries.

Disclosure of Invention

In view of the above problems, the present application provides a sodium ion layered oxide positive electrode material, a positive electrode sheet, a battery, and an electric device, which can solve the problem of poor water stability of a nickel-iron-manganese-based layered oxide.

In a first aspect, the present application provides a sodium ion layered oxide positive electrode material comprising Na _x Ni _a Fe _b Mn _c M ¹ _d M ² _e O _2-p A _p Wherein 0.6<x<1.2，0≤a，0≤b，0≤c，0≤d，0<e≤0.15，a+b+c+d+e=1，0<(a+b)/(c+d+e) is more than or equal to 19,0 and p is more than or equal to 0.1; the M is ¹ Comprises one or more elements from IA to VA groups and IB to VIIB groups, wherein M is ² Comprises one or more elements of Ga and Ta, wherein the A comprises one or more nonmetallic elements of VIA groups and VIIA groups.

The application mixes one or the Ga and the Ta in the sodium ion layered oxide anode material containing Ni and FeMultiple elements (M) ² ) Part M ² The elements occupy the surface positions of Ni and Fe on the sodium-ion layered oxide positive electrode material, so that the quantity of Ni and Fe on the surface of the sodium-ion layered oxide positive electrode material is reduced, and the M is ² The element itself has high stability and is not easy to coordinate with oxygen contained in water, thus M ² The doping of the element can reduce the element species which can coordinate with oxygen contained in water in the sodium ion layered oxide positive electrode material, thereby improving the water stability of the material.

At the same time, mn, M are matched ¹ And the proportion relation of the elements is regulated, so that the thermodynamic energy of the reaction of the sodium ion layered oxide anode material and water is increased, namely the difficulty of the reaction of the sodium ion layered oxide anode material and water is increased, thereby enhancing the structural stability of the sodium ion layered oxide anode material and further improving the water stability of the sodium ion layered oxide anode material.

In some embodiments, the M ¹ Including one or more of Cu, li, ti, K, nb, mg, ca, mo, zn, cr, W, bi, sn, ge, al, si, P, B. These metallic or nonmetallic elements, semimetallic elements and M ² Under the condition of Mn co-doping, the thermodynamic energy of the reaction of the sodium ion layered oxide anode material containing Ni and Fe and water is increased, which is favorable for inhibiting the reaction of the sodium ion layered oxide anode material and water and enhancing the water stability of the sodium ion layered oxide anode material.

In some embodiments, the a comprises one or more of F, cl, S. The oxygen site of the sodium ion layered oxide anode material is doped by utilizing the element A, which is beneficial to reducing oxygen defects in crystal lattices and improving the structural stability of the sodium ion layered oxide anode material.

In some embodiments, 0.01.ltoreq.e.ltoreq.0.15, alternatively 0.1.ltoreq.e.ltoreq.0.15. e represents the atomic ratio of Ga and Ta doping elements in the sodium ion layered oxide positive electrode material and reflects the doping amount of the Ga and Ta doping elements. Under proper doping amounts of Ga and Ta, the water stability of the sodium ion layered oxide anode material can be effectively improved, and meanwhile, the side effect on the capacity of the sodium ion layered oxide anode material is small.

In some embodiments, 0<(a+b)/(c+d+e) is less than or equal to 1.8, alternatively, 0<(a+b)/(c+d+e) is less than or equal to 1. (a+b)/(c+d+e) can reflect both Ni and Fe and Mn and M in the sodium-ion layered oxide positive electrode material ¹ 、M ² Ratios of Mn, M between the three ¹ 、M ² Can well inhibit the reaction of Ni and Fe with water and enhance the water stability of the sodium ion layered oxide anode material.

In some embodiments, 0.ltoreq.a.ltoreq.0.45, alternatively 0.ltoreq.a.ltoreq.0.4. a reflects the atomic ratio of Ni in the sodium-ion layered oxide cathode material. The specific capacity of the sodium ion layered oxide cathode material is improved under certain Ni content, and especially the specific capacity of the sodium ion layered oxide cathode material under high voltage is improved. Meanwhile, in the sodium ion layered oxide cathode material of the embodiment of the application, one or more elements of Ga and Ta and Mn and M ¹ The combined action can inhibit Ni from reacting with water to generate nickel oxide and side reaction with electrolyte in the electrochemical process to generate nickel oxide, and has good water stability.

In some embodiments, 0.ltoreq.b.ltoreq.0.5, alternatively, 0.19.ltoreq.b.ltoreq.0.39. b reflects the atomic ratio of Fe in the sodium-ion layered oxide cathode material. Under a certain Fe content, the specific capacity of the sodium ion layered oxide cathode material is improved, and especially the specific capacity of the sodium ion layered oxide cathode material under high voltage is improved. Meanwhile, in the sodium ion layered oxide positive electrode material of the embodiment of the application, one or more elements of Ga and Ta and Mn and M ¹ The combined action can inhibit Fe from reacting with water to generate iron oxide and generating side reaction with electrolyte in the electrochemical process to generate iron oxide, and has good water stability.

In some embodiments, 0.ltoreq.c.ltoreq.0.5. c can reflect the atomic ratio of Mn in the sodium-ion layered oxide positive electrode material, and Mn can be mixed with Ga, ta and M under the proper atomic ratio ¹ The elements together improve the water stability of the sodium ion layered oxide cathode material. At the same time, mn element improves sodium ion layered oxide positiveThe capacity of the pole material has a large influence.

In some embodiments, 0.ltoreq.d.ltoreq.0.2, alternatively 0.ltoreq.d.ltoreq.0.1. d may reflect M ¹ Atomic ratio in sodium-ion layered oxide cathode material, M at a suitable atomic ratio ¹ Can improve the water stability of the sodium ion layered oxide positive electrode material together with Ga, ta and Mn.

In some embodiments, the M ² The proportion of each element in the sodium ion layered oxide positive electrode material is Ga as follows:

x is more than or equal to 0.7 and less than or equal to 1, a is more than or equal to 0 and less than or equal to 0.39, b is more than or equal to 0, c is more than or equal to 0, d is more than or equal to 0, 0<e is less than or equal to 0.15, and a+b+c+d+e=1; 0< (a+b)/(c+d+e) is less than or equal to 1.8; or,

the M is ² For Ta, the proportion of each element in the sodium ion layered oxide positive electrode material is as follows:

0.6<x<1.2，0≤a，0≤b，0≤c≤0.5，0≤d，0<e≤0.15，a+b+c+d+e=1；0<（a+b）/(c+d+e)≤19。

Ga. The doping of Ta can improve the structure of the sodium ion layered oxide anode material, thereby improving the water stability of the material. Meanwhile, the improvement effect of Ga and Ta on the water stability of the sodium ion layered oxide anode material is also different to a certain extent. In the case of using different M ² In the case of (2), the proportion of each element in the sodium-ion layered oxide positive electrode material is adaptively adjusted and optimized, so that the different M can be fully developed ² Is effective in improving water stability.

In some embodiments, the sodium-ion layered oxide cathode material comprises NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.2 Mn _0.4 Cu _0.05 Ga _0.15 O ₂ 、NaNi _0.2 Fe _0.3 Mn _0.4 Cu _0.09 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Zn _0.1 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.3 0Mn _0.4 Mg _0.05 Ga _0.0 ₅ O ₂ 、NaNi _0.1 Fe _0.39 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 、NaFe _0.39 Mn _0.5 Cu _0.1 Ga _0.01 O ₂ 、NaNi _0.39 Fe _0.2 Mn _0.4 Ga _0.01 O ₂ 、NaNi _0.25 Fe _0.39 Mn _0.3 Cu _0.05 Ga _0.01 O ₂ 、Na _0.7 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.2 Fe _0.2 Mn _0.4 Cu _0.05 Ta _0.15 O ₂ 、NaNi _0.3 Fe _0.3 Mn _0.4 Cu _0.09 Ta _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Zn _0.1 Ta _0.01 O ₂ 、NaNi _0.2 Fe _0.30 Mn _0.4 Mg _0.05 Ta _0.0 ₅ O ₂ 、NaNi _0.3 Fe _0.19 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.1 Fe _0.39 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaFe _0.39 Mn _0.5 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.39 Mn _0.5 Zn _0.1 Ta _0.01 O ₂ 、NaNi _0.45 Fe _0.5 Cu _0.04 Ta _0.01 O ₂ 、NaNi _0.39 Fe _0.2 Mn _0.4 Ta _0.01 O ₂ 、Na _1.03 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、Na _0.7 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.25 Fe _0.39 Mn _0.3 Cu _0.05 Ta _0.01 O ₂ One or more of the following.

In some embodiments, the phase structure of the sodium-ion layered oxide cathode material comprises O ₃ Phase, O ₂ Phase, P ₂ Phase, P ₃ One or more of the phases.

In some embodiments, the spatial population of sodium ion layered oxide cathode material comprises、P63/mmcOne or more of the following.

In different phase structures or space groups, na ⁺ Has different coordination environments and contents, and TMO ₆ With different interlayer spacing, TMO, between structures ₆ With Na and Na ⁺ Is different and thus affects the structural stability of the layered oxide, and the Na that the layered oxide can provide ⁺ Content of Na ⁺ Is used for the ejection and embedding rates of the optical disc. The embodiment of the application has an improvement effect on the water stability of the sodium ion layered oxide anode material with different phase structures and space groups, and has wide applicability.

In a second aspect, the application provides a positive electrode sheet comprising a positive electrode active layer comprising the sodium ion layered oxide positive electrode material described above.

The sodium ion layered oxide anode material provided by the embodiment of the application has multiple element co-doping and good water stability. Therefore, after the sodium ion layered oxide positive electrode material is used as a positive electrode active material and applied to a positive electrode plate, the positive electrode plate can show good structural stability in the electrochemical circulation process, so that the electrochemical performance of the positive electrode plate is improved.

In a third aspect, the present application provides a battery comprising the positive electrode tab described above.

The positive electrode plate contains a sodium ion layered oxide positive electrode material, and the sodium ion layered oxide positive electrode material has multiple element co-doping and good water stability. Therefore, the positive electrode plate containing the sodium ion layered oxide positive electrode material is applied to manufacturing batteries, the requirements of the batteries on the moisture content in storage and use environments are reduced, the batteries can maintain good electrochemical performance in the aqueous environments, for example, the batteries are not easy to cause great reduction in capacity in the aqueous environments, and good cycle performance can be achieved in the aqueous environments.

In a fourth aspect, the present application provides an electrical device comprising the battery described above.

The battery disclosed by the embodiment of the application can be used for an electric device which takes the battery as a power supply or various energy storage systems which take the battery as an energy storage element for providing electric energy. The positive electrode plate of the battery comprises the sodium ion layered oxide positive electrode material with excellent water stability, and can improve the electrochemical properties of the battery such as the cycle stability and the like. Therefore, the battery can stably provide electric energy for various electric devices, and the use experience of the various electric devices is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram showing the crystal structure of a sodium-ion layered oxide positive electrode material according to an embodiment of the present application;

FIG. 2 is an X-ray diffraction spectrum of the sodium ion layered oxide cathode material of comparative example 1 before and after soaking in water, wherein b in the graph is an enlarged graph of the diffraction angle of 16.0-16.5 degrees in a graph;

FIG. 3 is an X-ray diffraction spectrum of the sodium-ion layered oxide cathode material of the embodiment A1 before and after soaking in water, wherein b in the graph is an enlarged graph of a diffraction angle of 16.0-16.5 degrees in a graph;

FIG. 4 is an X-ray diffraction spectrum of the sodium-ion layered oxide cathode material of the embodiment B1 before and after soaking in water, wherein B in the graph is an enlarged graph of a diffraction angle of 16.0-16.5 degrees in a graph;

FIG. 5 is an X-ray diffraction spectrum of the sodium-ion layered oxide cathode material of example C1 before and after soaking in water, wherein b in the graph is an enlarged graph of the diffraction angle of 16.0-16.5 DEG in a graph;

FIG. 6 is a schematic view of a battery according to an embodiment of the present application;

fig. 7 is an exploded view of the battery of the embodiment of the present application shown in fig. 6;

fig. 8 is a schematic view of a battery module according to an embodiment of the present application;

fig. 9 is a schematic view of a battery pack according to an embodiment of the present application;

fig. 10 is an exploded view of the battery pack of the embodiment of the present application shown in fig. 9;

fig. 11 is a schematic view of an electric device using a battery as a power source according to an embodiment of the present application.

Reference numerals:

a case 01 and a cover plate 02, an electrode assembly 03, a battery cell 04, a battery module 05, an upper case 06 and a lower case 07.

Detailed Description

Embodiments of the technical scheme of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, and are not intended to limit the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.

In the description of embodiments of the present application, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In the description of embodiments of the application, the term "at least one" means one or more, and "a plurality" means two or more. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, "at least one (individual) of a, b, or c," or "at least one (individual) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple, respectively.

It should be understood that, in various embodiments of the present application, the sequence number of each process described above does not mean that the execution sequence of some or all of the steps may be executed in parallel or executed sequentially, and the execution sequence of each process should be determined by its functions and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

The mass of the related components mentioned in the description of the embodiments of the present application may refer not only to the specific content of each component, but also to the proportional relationship between the mass of each component, so long as the content of the related component in the description of the embodiments of the present application is scaled up or down within the scope of the disclosure of the embodiments of the present application. Specifically, the mass described in the description of the embodiment of the application may be a mass unit known in the chemical industry field such as [ mu ] g, mg, g, kg.

The energy storage battery which is widely used at present is a lithium ion battery. However, lithium resources are low in abundance in nature, and high in production cost, and limit the development of lithium ion batteries. The sodium ion battery is widely distributed due to the fact that raw materials are abundant in nature, so that the sodium ion battery is widely focused and researched, and the problems of shortage of energy storage battery resources and high production cost are hopefully relieved.

The positive electrode material is a key factor for realizing high electrochemical performance of the sodium ion battery, such as high capacity, high voltage, long cycle life and the like. The positive electrode materials of sodium ion batteries which are studied more at present comprise layered oxides, polyanions, prussian blue analogues and the like. Among them, the layered oxide cathode material has been one of the research hot spots because it shows higher specific capacity, excellent performance, and simple synthesis than other cathode materials.

Research shows that Ni can be realized due to the existence of Ni and Fe elements in the nickel-iron-manganese-based layered oxide ²⁺ ~Ni ³⁺ ~Ni ⁴⁺ The two electrons are transferred, and the Fe element can provide charge compensation for the charge-discharge process, so the nickel-iron-manganese-based layered oxide shows high specific capacity. However, when the Ni and Fe contents are low, the nickel-iron-manganese-based layered oxide exhibits a low specific capacity at an operating voltage of 2.5V or higher. Meanwhile, related researches show that the specific capacity of the nickel-iron-manganese-based layered oxide increases with the increase of Ni and Fe contents. Therefore, in order for the nickel-iron-manganese-based layered oxide to exhibit a high specific capacity, it is generally required to increase the Ni, fe content therein. However, the nickel-iron-manganese-based layered oxide has a problem of poor water stability under high Ni and Fe contents, so that the performance of the sodium ion battery is easily deteriorated, and the sodium ion battery needs to be stored and used in a severe environment, which affects the development of the sodium ion battery.

The poor water stability of the nickel-iron-manganese-based layered oxide with high Ni and Fe contents is mainly shown in that the nickel-iron-manganese-based layered oxide has strong surface water absorption, and water is easy to dissociate on the surface of the nickel-iron-manganese-based layered oxide, so that Na is generated ⁺ /H ⁺ Exchange, resulting in a reduced Na content at the surface of the material. Surface of the body After a decrease in Na content, the material is susceptible to irreversible phase transitions, such as lamellar-spinel-salt phase transitions. This phase transition causes the surface of the positive electrode material to generate NiO and Fe ₃ O ₄ And the like, so that the electrochemical properties such as capacity, surface impedance and the like are obviously reduced.

In order to solve the problem of poor water stability of the nickel-iron-manganese-based layered oxide with high Ni and Fe contents, the related art forms a physical barrier between the sodium ion layered oxide anode material and the outside by coating the surface of the nickel-iron-manganese-based layered oxide, for example, coating the surface with a carbon material, titanium dioxide, aluminum oxide, copper oxide and the like. However, the nickel-iron-manganese-based layered oxide inevitably contacts with water vapor in the air in the coating process, so that a water absorption phenomenon can occur, and the crystal structure is changed, so that the electrochemical performance of the material is affected; and if the coating layer is damaged in the later application process, the nickel-iron-manganese-based layered oxide is exposed and then contacts with water, and various problems caused by poor water stability can also occur. Therefore, the surface coating method cannot fundamentally solve the problem of poor water stability of the nickel-iron-manganese-based layered oxide.

Aiming at the problems, the water stability of the nickel-iron-manganese-based layered oxide can be greatly improved by doping specific metal elements into the nickel-iron-manganese-based layered oxide.

The layered oxide positive electrode material doped with specific metal elements and having good water stability can be used as a positive electrode active material for manufacturing a positive electrode plate and further applied to manufacturing batteries and electric devices.

The application is further illustrated by the following examples. It is to be understood that these examples are illustrative of the present application and are not intended to limit the scope of the present application.

[ sodium ion layered oxide cathode Material ]

In a first aspect, an embodiment of the present application provides a sodium-ion layered oxide cathode material, including Na _x Ni _a Fe _b Mn _c M ¹ _d M ² _e O _2-p A _p Wherein 0.6<x<1.2，0≤a，0≤b，0≤c，0≤d，0<e≤0.15，a+b+c+d+e=1，0<（a+b）/(c+d+e)≤19，0≤p≤0.1；M ¹ Comprises one or more elements from IA to VA, IB to VIIB, M ² Comprises one or more elements of Ga, ta and Zr, wherein A comprises one or more nonmetallic elements of VIA group and VIIA group.

Wherein, the IA-VA groups comprise IA group, IIA group, IIIA group, IVA group and VA group, namely the first main group to the fifth main group in the periodic table of elements, and the main elements comprise alkali metal elements, alkaline earth metal elements, other metal elements, semi-metal elements, nonmetal elements and the like. The IB-VIIB groups comprise IB group, IIB group, IIIB group, IVB group, VB group, VIB group and VIIB group, namely the first subgroup to the seventh subgroup in the periodic table, and the main element is a transition metal element.

The embodiment of the application is characterized in that one or more elements (M) of Ga, ta and Zr are doped in a sodium ion layered oxide positive electrode material containing Ni and Fe ² ) As shown in the crystal structure of a sodium-ion layered oxide cathode material of FIG. 1 (M is not shown in FIG. 1) ¹ A, O), part M ² The elements occupy the surface positions of Ni and Fe on the sodium-ion layered oxide positive electrode material, so that the quantity of Ni and Fe on the surface of the sodium-ion layered oxide positive electrode material is reduced, and the M is ² The element itself has high stability and is not easy to coordinate with oxygen contained in water, thus M ² The doping of the element can reduce the element species which can coordinate with oxygen contained in water in the sodium ion layered oxide positive electrode material, thereby improving the water stability of the material.

In some embodiments, M ¹ Including one or more of Cu, li, ti, K, nb, mg, ca, mo, zn, cr, W, bi, sn, ge, al, si, P, B. These metal elements or Nonmetallic element, semimetallic element and M ² Under the condition of Mn co-doping, the thermodynamic energy of the reaction of the sodium ion layered oxide anode material containing Ni and Fe and water is increased, which is favorable for inhibiting the reaction of the sodium ion layered oxide anode material and water and enhancing the water stability of the sodium ion layered oxide anode material.

In some embodiments, a comprises one or more of F, cl, S. The oxygen site of the sodium ion layered oxide anode material is doped by utilizing the element A, which is beneficial to reducing oxygen defects in crystal lattices and improving the structural stability of the sodium ion layered oxide anode material.

In some embodiments, 0.01.ltoreq.e.ltoreq.0.15, alternatively 0.1.ltoreq.e.ltoreq.0.15. e may specifically include, but is not limited to, any one point value or range value between any two of 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.15.e represents the atomic ratio of three doping elements Ga, ta and Zr in the sodium ion layered oxide positive electrode material, and the doping amount is reflected. Under proper doping amounts of Ga, ta and Zr, the water stability of the sodium ion layered oxide positive electrode material can be effectively improved, and meanwhile, the side effect on the capacity of the sodium ion layered oxide positive electrode material is small.

In some embodiments, optionally 0<(a+b)/(c+d+e) is less than or equal to 1.8, alternatively, 0<(a+b)/(c+d+e) is less than or equal to 1, and still alternatively, 0.6 is less than or equal to (a+b)/(c+d+e) is less than or equal to 1. For example, (a+b)/(c+d+e) may include, but is not limited to, any one of the point values or range values between any two of 0.4, 0.5, 0.6, 0.62, 0.64, 0.66, 0.68, 0.7, 0.75, 0.8, 0.9, 0.95, 1, 1.5, 1.8, 2, 4, 6, 8, 10, 12, 14, 16, 18, 19. (a+b)/(c+d+e) can reflect both Ni and Fe and Mn and M in the sodium-ion layered oxide positive electrode material ¹ 、M ² Ratios of Mn, M between the three ¹ 、M ² Can well inhibit the reaction of Ni and Fe with water and enhance the water stability of the sodium ion layered oxide anode material.

At the same time, for different M ² The sodium ion layered oxide positive electrode material shows that when the value of (a+b)/(c+d+e) is differentThere is a certain difference in the water stability of (c). For M, for example ² In the case of including one or both of Ga and Zr, 0<(a+b)/(c+d+e) is less than or equal to 1.8, alternatively 0<The sodium ion layered oxide anode material with the ratio of (a+b)/(c+d+e) being less than or equal to 1 has better water stability; for M ² In the case of Ta included, at 0 <The sodium ion layered oxide anode materials with the ratio of (a+b)/(c+d+e) less than or equal to 19 all show good water stability.

In some embodiments, 0.7.ltoreq.x.ltoreq.1, alternatively 0.8.ltoreq.x.ltoreq.1. x may include, but is not limited to, any one point value or range value between any two of 0.65, 0.68, 0.7, 0.72, 0.74, 0.76, 0.78, 0.8, 0.82, 0.84, 0.86, 0.9, 0.92, 0.94, 0.96, 0.98, 1, 1.03, 1.1. x can reflect the atomic ratio of Na in the sodium ion layered oxide positive electrode material, wherein Na ions are used as key active ions participating in electrochemical reaction in a sodium ion battery, and the atomic ratio influences the capacity of the sodium ion layered oxide positive electrode material; meanwhile, na interacts with other metal elements in the crystal structure to form a stable layered structure. Therefore, at a proper Na ratio, the sodium-ion layered oxide cathode material has a high capacity and a stable crystal structure.

At the same time, for different M ² When the values of x are different, the water stability of the sodium ion layered oxide anode material is different to a certain extent. For M, for example ² Under the condition of comprising one or two of Ga and Zr, the sodium ion layered oxide anode material with x being more than or equal to 0.7 and less than or equal to 1 has better water stability; for M ² In the case of Ta included, at 0.6<x<1.2 sodium ion layered oxide cathode materials within a wide range all show good water stability.

In some embodiments, 0.ltoreq.a.ltoreq.0.45, alternatively 0.ltoreq.a.ltoreq.0.4, still alternatively 0.1.ltoreq.a.ltoreq.0.3. For example, a may include, but is not limited to, any one point value or range value between any two of 0, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.24, 0.25, 0.26, 0.28, 0.3, 0.32, 0.34, 0.36, 0.38, 0.39, 0.4, 0.42, 0.45. a reflects Ni in the sodium-ion layered oxide positive electrode materialAtomic ratio of (a). The specific capacity of the sodium ion layered oxide cathode material is improved under certain Ni content, and especially the specific capacity of the sodium ion layered oxide cathode material under high voltage is improved. Meanwhile, in the sodium ion layered oxide positive electrode material of the embodiment of the application, one or more elements of Ga, ta and Zr and Mn and M ¹ The combined action can inhibit Ni from reacting with water to generate nickel oxide and side reaction with electrolyte in the electrochemical process to generate nickel oxide, and has good water stability.

At the same time, for different M ² When the values of a are different, the water stability of the sodium ion layered oxide anode material is different to a certain extent. For M, for example ² In the case of Ga, 0.ltoreq.a.ltoreq.0.39, especially 0.ltoreq.a.ltoreq.0.2, and optionally 0.1.ltoreq.a.ltoreq.0.2, the sodium-ion layered oxide positive electrode material shows excellent water stability; for M ² Under the condition of Ta, the sodium ion layered oxide anode material with a range of a being more than or equal to 0 and less than or equal to 0.45 shows good water stability; for M ² In the case of Zr, 0.ltoreq.a.ltoreq.0.39, alternatively 0.1.ltoreq.a.ltoreq.0.3, the sodium ion layered oxide cathode material shows excellent water stability.

In some embodiments, 0.ltoreq.b.ltoreq.0.5, alternatively, 0.19.ltoreq.b.ltoreq.0.39, and still alternatively, 0.3.ltoreq.b.ltoreq.0.39. For example, b may include, but is not limited to, any one point value or range value between any two of 0, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5. b reflects the atomic ratio of Fe in the sodium-ion layered oxide cathode material. Under a certain Fe content, the specific capacity of the sodium ion layered oxide cathode material is improved, and especially the specific capacity of the sodium ion layered oxide cathode material under high voltage is improved. Meanwhile, in the sodium ion layered oxide positive electrode material of the embodiment of the application, one or more elements of Ga, ta and Zr and Mn and M ¹ The combined action can inhibit Fe from reacting with water to generate iron oxide and side reaction with electrolyte in the electrochemical process to generate iron oxide, and has good water stabilityAnd (5) qualitative property.

For different M ² When b values of the sodium ion layered oxide positive electrode materials are different, the water stability of the sodium ion layered oxide positive electrode materials is different to a certain extent. For M, for example ² In the case of Ga, b is more than or equal to 0.2 and less than or equal to 0.39, alternatively, b is more than or equal to 0.3 and less than or equal to 0.39, and the sodium ion layered oxide positive electrode material shows good water stability; for M ² Under the condition of Ta, the sodium ion layered oxide anode material with b being more than or equal to 0 and less than or equal to 0.5 shows good water stability; for M ² In the case of Zr, the sodium ion layered oxide anode material with b being more than or equal to 0.19 and less than or equal to 0.39 shows good water stability.

In some embodiments, 0.ltoreq.c.ltoreq.0.5, alternatively 0.ltoreq.c.ltoreq.0.4, or 0.3.ltoreq.c.ltoreq.0.5. For example, c may include, but is not limited to, any one point value or range value between any two of 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5. c can reflect the atomic ratio of Mn in the sodium-ion layered oxide positive electrode material, and Mn can be mixed with Ga, ta, zr and M under the proper atomic ratio ¹ The elements together improve the water stability of the sodium ion layered oxide cathode material. Meanwhile, mn element has a great influence on improving the capacity of the sodium ion layered oxide cathode material.

For different M ² When the values of c are different, the water stability of the sodium ion layered oxide anode material is different to a certain extent. For M, for example ² In the case of Ga, 0<c is optionally more than or equal to 0.3 and less than or equal to 0.5, and is further optionally more than or equal to 0.4 and less than or equal to 0.5, and the sodium ion layered oxide positive electrode material shows good water stability; for M ² In the case of Ta, the sodium ion layered oxide positive electrode material shows good water stability within a large range of 0-0 c, optionally 0-0.5 c; for M ² In the case of Zr, 0<c, optionally, the sodium ion layered oxide positive electrode material with c being more than or equal to 0.3 and less than or equal to 0.5 shows good water stability.

In some embodiments, 0.ltoreq.d.ltoreq.0.2, alternatively 0.ltoreq.d.ltoreq.0.1, and still alternatively 0.05.ltoreq.d.ltoreq.0.1. For example, d may include but is notIs limited to any one point value or a range value between any two points of 0, 0.01, 0.02, 0.04, 0.05, 0.06, 0.08, 0.09, 0.1, 0.12, 0.14, 0.16, 0.18 and 0.2. d may reflect M ¹ Atomic ratio in sodium-ion layered oxide cathode material, M at a suitable atomic ratio ¹ Can improve the water stability of the sodium ion layered oxide positive electrode material together with Ga, ta, zr and Mn.

In some embodiments, 0.ltoreq.p.ltoreq.0.1, alternatively 0.ltoreq.p.ltoreq.0.05. For example, p may include, but is not limited to, any one point value or range value between any two of 0, 0.01, 0.02, 0.04, 0.05, 0.06, 0.08, 0.1. And p can reflect the atomic ratio of A in the sodium-ion layered oxide positive electrode material, and under the proper atomic ratio, the A can reduce oxygen vacancies in the sodium-ion layered oxide positive electrode material, improve the stability of oxygen elements and further be beneficial to improving the electrochemical cycle performance of the sodium-ion layered oxide positive electrode material.

In some embodiments, M ² The proportion of each element in the Ga and Na-ion layered oxide positive electrode material is as follows:

x is more than or equal to 0.7 and less than or equal to 1, alternatively, x is more than or equal to 0.8 and less than or equal to 1;

a is more than or equal to 0 and less than or equal to 0.39, alternatively, a is more than or equal to 0 and less than or equal to 0.2, and further alternatively, a is more than or equal to 0.1 and less than or equal to 0.2;

0<b, optionally b is more than or equal to 0.2 and less than or equal to 0.39, and still optionally b is more than or equal to 0.3 and less than or equal to 0.39;

0<c, optionally c is more than or equal to 0.3 and less than or equal to 0.5, and further optionally c is more than or equal to 0.4 and less than or equal to 0.5;

d is more than or equal to 0 and less than or equal to 0, alternatively, d is more than or equal to 0 and less than or equal to 0.1, and further alternatively, d is more than or equal to 0.05 and less than or equal to 0.1;

0<e.ltoreq.0.15, optionally 0.01.ltoreq.e.ltoreq.0.15, still optionally 0.1.ltoreq.e.ltoreq.0.15;

a+b+c+d+e=1；

0< (a+b)/(c+d+e) is less than or equal to 1.8, alternatively 0< (a+b)/(c+d+e) is less than or equal to 1, and still alternatively 0.6 is less than or equal to (a+b)/(c+d+e) is less than or equal to 1.

In some embodiments, M ² The proportion of each element in the Ta and Na-ion layered oxide positive electrode material is as follows:

0.6<x<1.2，0.7≤x≤1；

0.ltoreq.a, optionally 0.ltoreq.a.ltoreq.0.45;

b is more than or equal to 0 and less than or equal to 0, alternatively, b is more than or equal to 0 and less than or equal to 0.5;

c is more than or equal to 0 and less than or equal to 0.5, alternatively, c is more than or equal to 0 and less than or equal to 0.4;

d is more than or equal to 0 and optionally more than or equal to 0 and less than or equal to 0.1;

a+b+c+d+e=1；

0< (a+b)/(c+d+e) is less than or equal to 19, alternatively 0.6 is less than or equal to (a+b)/(c+d+e) is less than or equal to 19.

In some embodiments, M ² The proportion of each element in the Zr and sodium ion layered oxide positive electrode material is as follows:

a is more than or equal to 0 and less than or equal to 0.39, alternatively, a is more than or equal to 0.1 and less than or equal to 0.3;

0<b, optionally 0.19.ltoreq.b.ltoreq.0.39;

0<c, optionally 0.3.ltoreq.c.ltoreq.0.5;

0<e.ltoreq.0.15, optionally 0.01< e.ltoreq.0.15, optionally 0.1.ltoreq.e.ltoreq.0.15;

a+b+c+d+e=1；

Ga. Ta, zr three M ² The doping of the elements can improve the structure of the sodium ion layered oxide anode material, thereby improving the water stability of the material. Meanwhile, the three elements have certain difference in the improvement effect on the water stability of the sodium ion layered oxide anode material. In the case of using different M ² In the case of (2), the proportion of each element in the sodium-ion layered oxide positive electrode material is adaptively adjusted and optimized, so that the different M can be fully developed ² Is effective in improving water stability.

In some embodiments, the sodium ion layered oxide cathode material comprises NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.2 Mn _0.4 Cu _0.05 Ga _0.15 O ₂ 、NaNi _0.2 Fe _0.3 Mn _0.4 Cu _0.09 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Zn _0.1 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.3 0Mn _0.4 Mg _0.05 Ga _0.0 ₅ O ₂ 、NaNi _0.1 Fe _0.39 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 、NaFe _0.39 Mn _0.5 Cu _0.1 Ga _0.01 O ₂ 、NaNi _0.39 Fe _0.2 Mn _0.4 Ga _0.01 O ₂ 、NaNi _0.25 Fe _0.39 Mn _0.3 Cu _0.05 Ga _0.01 O ₂ 、Na _0.7 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.2 Fe _0.2 Mn _0.4 Cu _0.05 Ta _0.15 O ₂ 、NaNi _0.3 Fe _0.3 Mn _0.4 Cu _0.09 Ta _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Zn _0.1 Ta _0.01 O ₂ 、NaNi _0.2 Fe _0.30 Mn _0.4 Mg _0.05 Ta _0.0 ₅ O ₂ 、NaNi _0.3 Fe _0.19 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.1 Fe _0.39 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaFe _0.39 Mn _0.5 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.39 Mn _0.5 Zn _0.1 Ta _0.01 O ₂ 、NaNi _0.45 Fe _0.5 Cu _0.04 Ta _0.01 O ₂ 、NaNi _0.39 Fe _0.2 Mn _0.4 Ta _0.01 O ₂ 、Na _1.03 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、Na _0.7 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.25 Fe _0.39 Mn _0.3 Cu _0.05 Ta _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Zr _0.01 O ₂ 、NaNi _0.2 Fe _0.2 Mn _0.4 Cu _0.05 Zr _0.15 O ₂ 、NaNi _0.2 Fe _0.3 Mn _0.4 Cu _0.09 Zr _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Zn _0.1 Zr _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Mg _0.1 Zr _0.01 O ₂ 、NaNi _0.3 Fe _0.19 Mn _0.4 Cu _0.1 Zr _0.01 O ₂ 、NaNi _0.1 Fe _0.39 Mn _0.4 Cu _0.1 Zr _0.01 O ₂ 、NaFe _0.39 Mn _0.5 Cu _0.1 Zr _0.01 O ₂ 、NaNi _0.39 Fe _0.2 Mn _0.4 Zr _0.01 O ₂ 、NaNi _0.2 ₅ Fe _0.39 Mn _0.3 Cu _0.05 Zr _0.01 O ₂ 、NaNi _0.39 Mn _0.5 Zn _0.1 Zr _0.01 O ₂ 、Na _0.7 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Zr _0.01 O ₂ One or more of the following.

In some embodiments, the phase structure of the sodium ion layered oxide cathode material includes one or more of an O3 phase, an O2 phase, a P2 phase, and a P3 phase. The sodium ion layered oxide positive electrode material may have a single phase structure or may be a composite of a plurality of phase structures. The phase structure of the sodium ion layered oxide cathode material optionally includes an O3 phase.

Layered oxide from TMO ₆ (TM represents transition metal, alkaline earth metal or other elements in the layered oxide; in the sodium-ion layered oxide cathode material of the embodiment of the application, TM comprises Mn, fe, ni, M ¹ And M ² ) Laminated structure is stacked, na ⁺ In TMO ₆ The layers of the stack are embedded and released. According to Na ⁺ The phase structure of the layered oxide can be divided into an O phase and a P phase according to different coordination environments; o represents Na ⁺ Is Octahedral coordination (Octahedral), na ⁺ Occupying octahedral sites; p represents Na ⁺ Is triangular prism coordination (prism), na ⁺ Occupying the triangular prism points. In the crystal structure, na ⁺ With TMO ₆ The structures are connected in the O-phase in a rib sharing manner, and in the P-phase in a face sharing and rib sharing manner.

The layered oxide may be further divided into a P2 phase, an O2 phase, a P3 phase, and an O3 phase according to the stacking order of the oxygen layers, wherein the stacking manner of P2 is ABBA, the stacking manner of O2 is ABAC (or ABCB), the stacking manner of P3 is ABBCCA, and the stacking manner of O3 is abcab. The numbers "2" and "3" represent the number of transition metal layers of the different kinds of O stacks in each cell.

Different phase structures correspond to different space groups, e.g. with O ₃ The space group corresponding to the corresponding structure isThe space group corresponding to the P2 phase structure is P63 +mmc。

The phase structure and space group can be obtained by X-ray pigment analysis. For example, the sample is tested by an X-ray powder diffractometer to obtain an X-ray diffraction spectrum of the sample, and the phase structure and space group of the sample can be confirmed by comparing the XRD diffraction peak in the X-ray diffraction spectrum with a standard card of XRD analysis software.

In different phase structures or space groups, na ⁺ With different coordination environments and contents, and a metal layer (TMO) ₆ Layer) structures having different layer spacing, TMO ₆ With Na and Na ⁺ Is different and thus affects the structural stability of the layered oxide, and the ability of the layered oxide toNa provided ⁺ Content of Na ⁺ Is used for the ejection and embedding rates of the optical disc. The embodiment of the application has an improvement effect on the water stability of the sodium ion layered oxide anode material with different phase structures and space groups, and has wide applicability.

In some embodiments, the interlayer spacing of the sodium ion layered oxide positive electrode material is 0.4 to 0.6nm, alternatively 0.5 to 0.6nm, and may include, for example, but not limited to, any one point value or a range value between any two of 0.4nm, 0.42nm, 0.44nm, 0.46nm, 0.48nm, 0.5nm, 0.52nm, 0.54nm, 0.56nm, 0.58nm, 0.6 nm. The interlayer spacing of the sodium ion layered oxide cathode material refers to the metal layer (TMO ₆ Layer) is understood to be the distance between adjacent oxygen atom layers on either side of the sodium layer. The interlayer distance can be obtained by obtaining X-ray diffraction information of the sodium ion layered oxide anode material and calculating the (003) crystal face peak position by combining with a Bragg equation. Na (Na) ⁺ In TMO ₆ Stacked interlaminar intercalation and deintercalation, na ⁺ The ion radius of (C) is about 0.096nm, so that Na can be supplied to a proper interlayer spacing ⁺ Is fast embedded and released, is favorable for improving Na ⁺ Improves the electrochemical performance of the sodium ion layered oxide positive electrode material.

In some embodiments, the Dv50 of the sodium ion layered oxide positive electrode material is 10-30 μm, alternatively 10-20 μm, and may include, for example, but not limited to, any one point value or a range value between any two of 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 25 μm, 26 μm, 28 μm, 30 μm.

For the particle size distribution of a material, it is generally expressed as a percentage of the total amount of particles in the different size ranges. The particle size distribution is measured by various methods such as a numerical distribution, a length distribution, an area distribution, a volume distribution, a weight distribution, and the like. Dv50 is a specific particle size distribution based on volume distribution, also called median particle diameter, and refers to a particle size where the cumulative distribution of particle volumes is 50%, meaning that 50% of the particles have a diameter exceeding this value and 50% of the particles have a diameter below this value. The Dv50 of the particles can be tested by reference to GB/T19077-2016/ISO 13320:2009 particle size distribution laser diffraction. In the embodiment of the application, the particle morphology of the sodium ion layered oxide anode material can be regular spherical, elliptic, polygonal or other irregular shapes, and the particle diameter of the spherical particles is the diameter of the spherical particles; for particles that are non-spherical, or other irregularly shaped, the particle size is its equivalent diameter. The sodium ion layered oxide anode material provided by the embodiment of the application has proper Dv50, and is beneficial to the application of the sodium ion layered oxide anode material in the preparation of uniform anode slurry; and the micron-sized median particle size has lower requirements on the preparation process, and is beneficial to the control of cost.

In some embodiments, the specific surface area of the sodium ion layered oxide positive electrode material is 0.1 to 5m ² /g, optionally 0.3-3 m ² /g, may include, for example, but not limited to, 0.1m ² /g、0.3m ² /g、0.5m ² /g、1m ² /g、1.5m ² /g、2m ² /g、2.5m ² /g、3m ² /g、3.5m ² /g、4m ² /g、4.5m ² /g、5m ² Any one point value or any range value between the two points in/g. The specific surface area can be obtained by referring to GB/T19587-2017, measuring the specific surface area of solid substances by a gas adsorption BET method and adopting a nitrogen adsorption specific surface area analysis test method. The appropriate specific surface area range helps achieve higher gram capacity, first coulombic efficiency and cycle life.

In some embodiments, the tap density of the sodium ion layered oxide positive electrode material is 1-3 g/cm ³ Optionally 1.5-2.5 g/cm ³ May include, for example, but not limited to, 1g/cm ³ 、1.2g/cm ³ 、1.4g/cm ³ 、1.5g/cm ³ 、1.6g/cm ³ 、1.8g/cm ³ 、2g/cm ³ 、2.2g/cm ³ 、2.4g/cm ³ 、2.5g/cm ³ 、2.6g/cm ³ 、2.8g/cm ³ 、3g/cm ³ Any one point value or a range value between any two. Tap density refers to the density of a powder contained in a container after being tapped under prescribed conditions. Tap density can reflect the flow of powderProperties such as sex and void fraction. By way of example, tap density can be determined by means of a tap densitometer with reference to GB/T5162-2021 determination of tap Density of metallic powder. When the tap density is high, the sodium ion layered oxide positive electrode material with higher quality can store more sodium ions and improve the energy density of the positive electrode plate under the same volume in the process of applying the sodium ion layered oxide positive electrode material to manufacturing the positive electrode plate. That is, tap density affects the energy density of the pole piece. Meanwhile, the tap density also reflects the porosity of the powder, and under proper porosity, the pole piece has good electrolyte infiltration performance, and sodium ions are convenient to transmit. The sodium ion layered oxide anode material provided by the embodiment of the application has proper tap density, is beneficial to improving the energy density of the pole piece, is beneficial to improving the electrolyte infiltration performance of the pole piece, and accelerates the transmission of sodium ions.

In some embodiments, the sodium ion layered oxide positive electrode material has a powder compaction density of 3-5 g/cm at a pressure of 8 tons ³ Optionally 3.5-4.5 g/cm ³ May include, for example, but not limited to, 3g/cm ³ 、3.2g/cm ³ 、3.4g/cm ³ 、3.5g/cm ³ 、3.6g/cm ³ 、3.8g/cm ³ 、4g/cm ³ 、4.2g/cm ³ 、4.4g/cm ³ 、4.5g/cm ³ 、4.6g/cm ³ 、4.8g/cm ³ 、5g/cm ³ Any one point value or a range value between any two. The compacted density is the density of the powder at a certain pressure, compacted density = areal density/thickness of the material. The compacted density can be obtained by a compacted density meter with reference to relevant standards, such as annex L test method for compacted density of powder in GB/T24533-2019. The compaction density has an effect on the energy density of the pole piece, electrolyte wetting performance, sodium ion transport rate, and the like. The greater the compaction density, the higher the mass of the sodium ion layered oxide positive electrode material in the unit volume, which is beneficial to improving the energy density of the pole piece. Meanwhile, the compaction density also reflects the porosity of the pole piece, and the pole piece has good electrolyte infiltration performance under proper porosity, thereby facilitating the transmission of sodium ions. Sodium ions of the embodiment of the applicationThe layered oxide anode material has proper compaction density, which is beneficial to not only improving the energy density of the pole piece, but also improving the electrolyte infiltration performance of the pole piece and accelerating the transmission of sodium ions.

[ preparation of sodium-ion layered oxide cathode Material ]

The sodium ion layered oxide anode material of the embodiment of the application can be prepared by one or more of a solid phase method and a coprecipitation method, and the specific preparation method can be referred to as follows.

1. Solid phase method

The sodium ion layered oxide cathode material can be prepared by a solid phase method, and the method comprises the following steps:

according to Na _x Ni _a Fe _b Mn _c M ¹ _d M ² _e O _2-p A _p Is composed of Na source, mn source, fe source, ni source, M ¹ Source, M ² The source and the source A are calcined together to obtain a sodium ion layered oxide anode material;

wherein 0.6<x<1.2，0≤a，0≤b，0≤c，0≤d，0<e≤0.15，a+b+c+d+e=1，0<（a+b）/(c+d+e)≤19，0≤p≤0.1；M ¹ Comprises one or more elements from IA to VA, IB to VIIB, M ² Comprises one or more elements of Ga, ta and Zr, wherein A comprises one or more nonmetallic elements of VIA group and VIIA group.

The sodium ion layered oxide anode material with multiple co-doping elements can be obtained by adopting a solid phase method to perform co-calcination treatment on various raw materials, and the preparation method is simple and is suitable for large-scale production. The obtained sodium ion layered oxide positive electrode material is simultaneously doped with M ¹ 、Mn、M ² A plurality of elements with proper element content and proportion relation, on one hand, part M ² The elements occupy the surface positions of Ni and Fe on the sodium-ion layered oxide positive electrode material, so that the quantity of Ni and Fe on the surface of the sodium-ion layered oxide positive electrode material is reduced, and the M is ² The element itself has high stability and is not easy to coordinate with oxygen contained in water, thus M ² Doping of elements canThe element species capable of coordinating with oxygen contained in water in the sodium ion layered oxide positive electrode material is reduced, so that the water stability of the material is improved. On the other hand, the thermodynamic energy of the reaction of the sodium ion layered oxide positive electrode material and water is increased, namely the difficulty of the reaction of the sodium ion layered oxide positive electrode material and water is increased, so that the structural stability of the sodium ion layered oxide positive electrode material is enhanced, and the water stability of the sodium ion layered oxide positive electrode material is further improved.

In some embodiments, the calcination process is performed at a temperature of 600 to 1200 ℃, optionally 800 to 1000 ℃, and may include, for example, but not limited to, any one point value or a range value between any two of 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃, 1050 ℃, 1100 ℃, 1150 ℃ and 1200 ℃. The heat preservation time at the temperature of the calcination treatment is 10-20 h, optionally 10-15 h, and can include, for example, any one point value or a range value between any two points of 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h and 20 h. The temperature of the calcination treatment and the holding time at that temperature can be set and controlled directly on the calcination apparatus, such as a muffle furnace. Under proper calcination temperature and time, the raw materials can be fully melted and mixed and react to form the composite metal oxide.

In some embodiments, the rate of temperature rise during the calcination process is 2-10 ℃/min, optionally 3-5 ℃/min, and may include, for example, but not limited to, any one point value or range value between any two of 2 ℃/min, 3 ℃/min, 4 ℃/min, 5 ℃/min, 6 ℃/min, 7 ℃/min, 8 ℃/min, 9 ℃/min, 10 ℃/min. The rate of temperature rise herein refers to the rate of change of temperature during the temperature rise to the desired temperature for calcination. The temperature rising rate is one of key factors influencing the grain size and the grain morphology of the material, and under the temperature rising rate of the embodiment of the application, the sodium ion layered oxide positive electrode material can have proper grain size and complete grain morphology.

After the calcination treatment is finished, the product can be cooled down by adopting a natural cooling mode.

In some embodiments, the method of preparing a sodium ion layered oxide cathode material may optionally further comprise a pre-calcination treatment step. The temperature of the pre-calcination treatment may be set to 600-900 ℃, optionally 800-900 ℃, and may include, for example, but not limited to, any one point value or a range value between any two of 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃ and 900 ℃. The heat preservation time at the temperature of the pre-calcination treatment is 10-20 h, optionally 10-15 h, and can include, for example, any one point value or a range value between any two points of 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h and 20 h. The pre-calcination treatment step may be provided before the calcination treatment step. Pre-calcination is the prior heat treatment of the feedstock at a temperature below the final calcination temperature prior to final calcination of the feedstock. The pre-calcination treatment is carried out on the raw materials, so that impurities in the raw materials can be removed, and the purity of the product can be improved; and is beneficial to improving the crystal morphology of the product.

The calcination treatment step and the preliminary calcination treatment step may be performed in an air or oxygen atmosphere.

In some embodiments, the method for preparing the sodium ion layered oxide cathode material further comprises mixing a Na source, a Mn source, a Fe source, a Ni source, and M ¹ Source, M ² And mixing the source and the source A. Methods of mixing include, but are not limited to, one or more of mechanical stirring, milling, ball milling. Illustratively, milling may be performed first followed by ball milling. Through the mixing treatment steps, various raw materials can be mixed uniformly, the particle size of the raw materials can be reduced, and the calcination is facilitated to prepare the sodium ion layered oxide positive electrode material with the required particle size.

In the solid phase method, na source, mn source, fe source, ni source and M ¹ Source, M ² The source, a source, each independently can be selected from their respective soluble or insoluble compounds. For example, the specific species of each raw material may be selected from the following compounds:

na sources include, but are not limited to Na ₂ CO ₃ 、NaHCO ₃ 、NaOH、Na ₂ O ₂ One or more of the other sodium salts;

ni sources include, but are not limited to NiO, ni (OH) ₂ One or more of the following;

fe sources include, but are not limited to, fe ₂ O ₃ 、Fe ₃ O ₄ One or more of FeO;

mn sources include, but are not limited to Mn ₂ O ₃ 、Mn ₃ O ₄ 、MnO、MnO ₂ One or more of the following;

M ¹ sources include, but are not limited to, M-containing ¹ Oxide of (C) containing M ¹ Is a hydroxide of (C) and M-containing ¹ Carbonate of (C) containing M ¹ One or more of the bicarbonate salts of (a);

M ² sources include, but are not limited to, M-containing ² Oxide of (C) containing M ² Is a hydroxide of (C) and M-containing ² Carbonate of (C) containing M ² One or more of the bicarbonate salts of (a);

the source A includes, but is not limited to, one or more of metal A-compounds, metal A-acid salts, wherein the metal A-compounds and metal A-acid salts contain metal elements including Na, fe, mn, ni, M ¹ 、M ² One or more of the following; to reduce the negative influence of other metal elements on the performance of the sodium ion layered oxide positive electrode material, na, fe, mn, ni, M is not generated in the source A as much as possible ¹ 、M ² Other metal elements.

2. Coprecipitation method

The sodium ion layered oxide cathode material may also be prepared by a coprecipitation method, which may include:

providing Mn-containing source, fe-containing source, ni-containing source, M ¹ Source, M ² Performing coprecipitation treatment on the mixed solution of the source and the source A to obtain a precursor;

calcining the precursor and a Na source to obtain a sodium ion layered oxide anode material;

therein, na, mn, fe, ni, M ¹ 、M ² The molar ratio of A satisfies Na _x Ni _a Fe _b Mn _c M ¹ _d M ² _e O _2-p A _p ，0.6<x<1.2，0≤a，0≤b，0≤c，0≤d，0<e≤0.15，a+b+c+d+e=1，0<（a+b）/(c+d+e)≤19，0≤p≤0.1；M ¹ Comprises one or more elements from IA to VA, IB to VIIB, M ² Comprises one or more elements of Ga, ta and Zr, wherein A comprises one or more nonmetallic elements of VIA group and VIIA group.

The precursor is obtained by coprecipitation treatment of elements except Na, and then Na source is added for calcination treatment, so that the sodium-ion layered oxide anode material with multiple co-doping elements can be obtained, and the preparation method is simple and suitable for mass production. The obtained sodium ion layered oxide positive electrode material is simultaneously doped with M ¹ 、Mn、M ² A plurality of elements with proper element content and proportion relation, on one hand, part M ² The elements occupy the surface positions of Ni and Fe on the sodium-ion layered oxide positive electrode material, so that the quantity of Ni and Fe on the surface of the sodium-ion layered oxide positive electrode material is reduced, and the M is ² The element itself has high stability and is not easy to coordinate with oxygen contained in water, thus M ² The doping of the element can reduce the element species which can coordinate with oxygen contained in water in the sodium ion layered oxide positive electrode material, thereby improving the water stability of the material. On the other hand, the thermodynamic energy of the reaction of the sodium ion layered oxide positive electrode material and water is increased, namely the difficulty of the reaction of the sodium ion layered oxide positive electrode material and water is increased, so that the structural stability of the sodium ion layered oxide positive electrode material is enhanced, and the water stability of the sodium ion layered oxide positive electrode material is further improved.

In some embodiments, the step of co-precipitation treatment comprises: the mixed solution is reacted with a precipitant. Wherein the precipitant comprises a compound containing one or more of hydroxide ion, carbonate ion and oxalate ion. In practice, the mixed solution may be mixed with a precipitant, or the mixed solution may be mixed with a solution containing a precipitant, and then a precipitation reaction occurs spontaneously.

In the coprecipitation method, mn source, fe source, ni source and M ¹ Source, M ² The source, source A, each independently may select its respective soluble compound, optionally including itRespective water-soluble compounds. For example, the specific species of each raw material may be selected from the following compounds:

the Ni source may include, but is not limited to, one or more of a chloride of Ni, a sulfate of Ni, a nitrate of Ni;

the Fe source may include, but is not limited to, one or more of a chloride of Fe, a sulfate of Fe, a nitrate of Fe;

the Mn source may include, but is not limited to, one or more of a chloride of Mn, a sulfate of Mn, a nitrate of Mn;

M ¹ sources may include, but are not limited to, M ¹ Chloride, M of ¹ Sulfate, M of (2) ¹ One or more of the nitrates of (b);

M ² sources may include, but are not limited to, M ² Chloride, M of ² Sulfate, M of (2) ² One or more of the nitrates of (b);

the source A may include, but is not limited to, one or more of a metal A-compound, a metal A-acid salt, wherein the metal A-compound and metal A-acid salt may include Na, fe, mn, ni, M as the metal element ¹ 、M ² One or more of the following; to reduce the negative influence of other metal elements on the performance of the sodium ion layered oxide positive electrode material, na, fe, mn, ni, M is not generated in the source A as much as possible ¹ 、M ² Other metal elements.

For the Na source, a soluble or insoluble compound of Na may be selected, and may include, for example, but not limited to Na ₂ CO ₃ 、NaHCO ₃ 、NaOH、Na ₂ O ₂ And one or more of the other sodium salts.

It will be appreciated that the solvent in the mixed solution should have the ability to dissolve these materials, corresponding to the types of materials described above, for example the solvent may comprise one or more of water, ethanol, optionally water.

In the coprecipitation method, the temperature, time and heating rate of the calcination treatment are the same as those of the solid phase method, or a preliminary calcination treatment step may be added before the calcination treatment as needed, and the temperature and time of the preliminary calcination treatment are the same as those of the solid phase method. The calcination treatment step and the preliminary calcination treatment step may be performed in an air or oxygen atmosphere.

Meanwhile, before the calcination treatment (or before the pre-calcination treatment), a step of mixing the precursor with a Na source may be further included. Methods of mixing include, but are not limited to, one or more of mechanical stirring, milling, ball milling. Illustratively, milling may be performed first followed by ball milling.

[ Positive electrode sheet ]

The second aspect of the embodiment of the application provides a positive electrode plate, which comprises a positive electrode active layer, wherein the positive electrode active layer comprises the sodium ion layered oxide positive electrode material.

In some embodiments, the mass content of the sodium ion layered oxide positive electrode material in the positive electrode active layer is 50% -98%, alternatively 80% -95%, for example, may include, but is not limited to, any one point value or a range value between any two of 50%, 55%, 60%, 65%, 70%, 75%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, 96%, 98%. The sodium ion layered oxide positive electrode material can be used as the only positive electrode active material in the positive electrode plate, can be blended with other positive electrode active materials according to a certain proportion or jointly distributed in the positive electrode active layer according to a certain mode, and can comprise one or more of layered oxide positive electrode materials, prussian blue positive electrode materials and polyanion positive electrode materials with other compositions. Therefore, the mass content of the sodium ion layered oxide positive electrode material in the positive electrode active layer can be determined according to the actual situation. It is understood that the high mass content of the sodium ion layered oxide positive electrode material in the positive electrode active layer will be beneficial to improve the structural stability of the positive electrode sheet.

In some embodiments, the positive electrode active layer further includes one or more of a conductive agent, a binder. The conductive agent is used for collecting micro-current between the active materials and the current collector, so that the electronic conductivity is improved, and meanwhile, the conductive agent can also promote the infiltration of the electrolyte to the positive electrode plate. The binder can then increase the bond strength between the substances in the active layer and between the active layer and the current collector.

In some embodiments, the mass content of the conductive agent in the positive electrode active layer is 0.5% -10%, optionally 1% -7%, for example, any one point value or any range value between any two of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, and may be set to other content as required.

In some embodiments, the conductive agent includes one or more of acetylene black (SP), carbon nanotubes, conductive carbon black (super-P), ketjen black, carbon fibers, graphene.

In some embodiments, the mass content of the binder in the positive electrode active layer is 0.5% -15%, optionally 1% -7%, for example, any one point value or a range value between any two points of 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and may be set to other content as required.

In some embodiments, the binder includes, but is not limited to, one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polyimide, polytetrafluoroethylene, polybutyl acrylate, polyacrylonitrile, carboxymethyl cellulose salt, polyacrylic acid, polyacrylate, polyvinyl alcohol, sodium alginate, cyclodextrin, styrene-butadiene rubber, vinyl acetate resin, acrylic resin, chlorinated rubber.

In some embodiments, the positive electrode active layer also optionally includes a thickener, such as carboxymethyl cellulose (CMC). The mass content of the thickener in the positive electrode active layer may be set to 0.5% -5%, optionally 1% -5%, including but not limited to any one point value or a range value between any two of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%. The thickener is beneficial to improving the viscosity degree of the positive electrode slurry and improving the processing performance of the positive electrode slurry.

In some embodiments, the positive electrode active layer may further optionally include a sodium supplement additive, such as one or more of a transition metal sodium salt, sodium azide, squaraine sodium salt, prussian blue sodium salt. The mass content of the sodium supplement additive in the positive electrode active layer may be set to be 0.1% -20%, for example, 0.1%, 0.5%, 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20% or a range between any two. The sodium supplementing additive can remove sodium ions in the electrochemical reaction, supplement sodium ions lost by the positive electrode active material in the charging and discharging processes of the battery, improve the capacity of the battery and prolong the service life of the battery.

In some embodiments, the positive electrode tab further includes a positive electrode current collector, and the positive electrode active layer is disposed on at least one side of the positive electrode current collector. The current collector is used for transporting electrons. In an embodiment of the present application, the positive electrode current collector may include, but is not limited to, a metal current collector, a carbon current collector, a conductive resin current collector, a metal and resin composite current collector, etc., more specifically, for example, aluminum, copper, nickel, titanium, iron, their alloys, stainless steel, carbon fiber, carbon Nanotube (CNT), graphite, etc. Optionally, the positive electrode current collector comprises aluminum.

The positive electrode plate of the embodiment of the application can be manufactured through the working procedures of pulping, coating, drying, compacting and the like.

Illustratively, the positive electrode sheet may be fabricated as follows:

mixing a sodium ion layered oxide positive electrode material, a conductive agent and a binder (a thickening agent or other positive electrode active materials and other additives can be added according to the requirement) with a solvent to obtain positive electrode slurry;

and coating the positive electrode slurry on a current collector, and drying and compacting to obtain the positive electrode plate.

The solvent may include, but is not limited to, N-methylpyrrolidone (NMP). The compaction method may include one or more of hot pressing, cold pressing, and the amount of pressure employed in the compaction step may be determined based on the target compaction density.

[ Battery ]

The positive electrode plate containing the sodium ion layered oxide positive electrode material can be applied to manufacturing batteries.

A third aspect of the embodiment of the present application provides a battery, which includes the positive electrode sheet described above.

According to different packaging forms, the battery is divided into a battery cell, a battery module and a battery pack. The battery of the embodiment of the application comprises one or more of a battery monomer, a battery module and a battery pack.

Typically, the battery includes a positive electrode tab, a negative electrode tab, an electrolyte, a separator, and an outer package or other components. The following describes the components other than the positive electrode sheet in the battery.

1. Negative pole piece

In a battery, the negative electrode tab is typically isolated from the positive electrode tab. The negative electrode tab includes a negative electrode current collector, and optionally includes a negative electrode active layer disposed on at least one side of the negative electrode current collector, the negative electrode active layer including a negative electrode active material.

Wherein the negative electrode current collector may include, but is not limited to, a metal or a composite current collector. For example, as the metal, sodium, a sodium alloy, copper, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, a silver alloy, or the like can be used. In the case of using sodium or a sodium alloy as the negative electrode current collector, since sodium or a sodium alloy itself may also be used as the negative electrode active material, the negative electrode tab may not contain a negative electrode active layer, and sodium or a sodium alloy is both the current collector and the negative electrode active material.

The composite current collector may include a composite material of a polymer material including, but not limited to, polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc., and a metal including, but not limited to, sodium, copper alloy, nickel alloy, titanium alloy, silver alloy. The composite current collector may be obtained by blending a polymer material with a metal, or may be coated on at least one side of the polymer material by electroplating, coating or other means.

In the case where the negative electrode tab includes a negative electrode active layer, the negative electrode active material in the negative electrode active layer may include, but is not limited to, a mixed or composite material formed of any one or more of a carbon-based material, an alloy material, a titanium-based material, and a sodium metal. Wherein the carbon-based material includes, but is not limited to, one or more of graphite, soft carbon, hard carbon, carbon microspheres, carbon fibers; alloy materials include, but are not limited to, one or more of sodium tin alloy, sodium germanium alloy, sodium antimony alloy; titanium-based materials include, but are not limited to, one or more of titanium dioxide, titanates, titanophosphate.

The mass content of the anode active material in the anode active layer may be set to 85% to 98%, alternatively 95% to 98%, for example, any one point value or a range value between any two of 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%.

The anode active layer may further include one or more of a conductive agent and a binder. The conductive agent is used for collecting micro-current between the active materials and the current collector, so that the electronic conductivity is improved, and meanwhile, the conductive agent can also promote the infiltration of the electrolyte to the negative electrode plate. The binder can then increase the bond strength between the substances in the active layer and between the active layer and the current collector.

The mass content of the conductive agent in the anode active layer may be set to 0.5% to 10%, for example, any one of 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or a range between any two, or may be set to other content as required.

The conductive agent comprises one or more of acetylene black (SP), carbon nanotubes, conductive carbon black (super-P), ketjen black, carbon fiber and graphene.

The mass content of the binder in the negative electrode active layer is 0.5% to 10%, for example, any one of 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or a range between any two, and may be set to other content as required.

The binder includes, but is not limited to, one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polyimide, polytetrafluoroethylene, polybutyl acrylate, polyacrylonitrile, carboxymethyl cellulose salt, polyacrylic acid, polyacrylate, polyvinyl alcohol, sodium alginate, cyclodextrin, styrene-butadiene rubber, vinyl acetate resin, acrylic resin, chlorinated rubber.

The anode active layer may also optionally include a thickener, such as carboxymethyl cellulose (CMC). The mass content of the thickener in the positive electrode active layer may be set to any one point value or a range value between any two of 0.5% -5%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%.

And under the condition that the current collector is the negative electrode active material, the negative electrode plate can be obtained by slitting the current collector.

In the case where the negative electrode tab includes a negative electrode active layer, the negative electrode active material may be coated on at least one side of the current collector by physical vapor deposition, chemical vapor deposition, electroplating, or the like. Alternatively, the negative electrode sheet may be formed by pulping, coating, drying, compacting, or the like, for example, by mixing a negative electrode active material, a conductive agent, a binder (optionally, other additives may be added as needed) with a solvent to obtain a negative electrode slurry; and coating the negative electrode slurry on a current collector, and drying and compacting to obtain the negative electrode plate. The solvent may include, but is not limited to, N-methylpyrrolidone (NMP). The compaction method may include one or more of hot pressing, cold pressing, and the amount of pressure employed in the compaction step may be determined based on the target compaction density.

2. Electrolyte composition

The battery also comprises electrolyte solution, and the positive electrode plate and the negative electrode plate are respectively and independently contacted with the electrolyte. The electrolyte plays a role in ion conduction between the positive electrode plate and the negative electrode plate. The application is not particularly limited in the kind of electrolyte, and may be selected according to the need. For example, the electrolyte may be liquid, gel, or all solid.

The electrolyte may be an electrolyte solution including an electrolyte salt and a solvent.

The electrolyte salt includes one or more of sodium hexafluorophosphate, sodium difluorosulfimide, sodium trifluoromethylsulfonate, sodium sulfide, sodium chloride, sodium fluoride, sodium sulfate, sodium carbonate, sodium phosphate, sodium nitrate, sodium difluorooxalato borate, sodium pyrophosphate, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, trisodium citrate, sodium metaborate, sodium borate, sodium molybdate, sodium tungstate, sodium bromide, sodium nitrite, sodium iodate, sodium iodide, sodium silicate, sodium lignin sulfonate, sodium oxalate, sodium aluminate, sodium methylsulfonate, sodium acetate, sodium dichromate, sodium hexafluoroarsenate, sodium tetrafluoroborate, sodium perchlorate, sodium trifluoromethylsulfonamide.

The solvent includes one or more of Ethylene Carbonate (EC), methylethyl carbonate (EMC), dimethyl ether (DME), diethylene glycol dimethyl ether, diethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, 2, 2, 2-trifluoroethyl ether, ethylene glycol diethyl ether, triethylene glycol dimethyl ether, methyltrifluoroethyl carbonate (FEMC), dioxolane (DOL), acetonitrile (AN), fluorobenzene, triethyl phosphate (TEP), sulfolane, 2-methyltetrahydrofuran, tetrahydrofuran, dimethyl sulfoxide, N dimethylacetamide.

The electrolyte may also include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives capable of improving certain properties of the battery, such as additives that improve the overcharge performance of the battery, additives that improve the high or low temperature performance of the battery, and the like.

3. Isolation film

The battery also comprises an isolating film which is arranged between the positive pole piece and the negative pole piece and can separate the positive pole from the negative pole. The isolating film can prevent the electrons in the battery from passing through freely and prevent the electrodes from being in short circuit, but can allow the ions in the electrolyte to pass through freely between the positive electrode plate and the negative electrode plate.

The separator may be any known porous separator having electrochemical stability and mechanical stability, such as a single-layer or multi-layer film of one or more of glass fiber, nonwoven fabric, polyethylene (PE), polypropylene (PP) and polyvinylidene fluoride (PVDF).

4. External packing

The battery may include an outer package. The outer package may be used to encapsulate an electrode assembly comprising a positive electrode, a negative electrode, a separator, and an electrolyte.

The outer package of the battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, or the like; but may also be a flexible bag, such as a bag-type flexible bag. The soft bag can be made of plastics such as polypropylene, polybutylene terephthalate, polybutylene succinate and the like.

The shape of the outer package of the battery may be cylindrical, square or any other shape. For example, fig. 6 shows a battery having a square outer package as an example.

Referring to fig. 7, the outer package may include a housing 01 and a cover 02. The casing 01 may include a bottom plate and a side plate connected to the bottom plate, where the bottom plate and the side plate enclose a containing cavity. The housing 01 has an opening communicating with the accommodation chamber, and the cover plate 02 can be provided to cover the opening to close the accommodation chamber. The positive electrode sheet, the negative electrode sheet and the separator may be formed into the electrode assembly 03 through a winding process or a lamination process. One or more electrode assemblies 03 are enclosed in the receiving chamber. The electrolyte is impregnated in the electrode assembly 03.

5. Battery monomer, battery module and battery package

The battery of the embodiment of the application comprises one or more of a battery monomer, a battery module and a battery pack.

The secondary battery is divided into a battery cell, a battery module, and a battery pack according to different packaging forms. Among them, the battery cell is the most basic unit of a secondary battery, and includes an electrode assembly, which generally includes a positive electrode, a negative electrode, a lithium supplementing electrode, and a separator. The positive pole piece and the negative pole piece are alternately laminated, and an isolating film is arranged between the positive pole piece and the negative pole piece to play a role in isolation, so that the bare cell is obtained, or the bare cell can be obtained after winding. And placing the bare cell in an outer package, injecting electrolyte, and packaging to obtain the battery cell.

The battery module is formed by integrating one or more battery cells, and can provide higher voltage and capacity and output with specific functions. One or more battery modules are mounted in a case of a battery, and a battery management system or the like is generally added to form a battery pack. The battery pack is typically a product provided to the user. Alternatively, one or more battery cells may be directly mounted in the case to form a battery pack.

Referring to fig. 8, there is shown an exemplary battery module. In the battery module, the plurality of battery cells 04 may be sequentially arranged in the longitudinal direction of the battery module. Of course, the arrangement may be performed in any other way. The plurality of battery cells 04 may be further fixed by fasteners.

Alternatively, the battery module may further include a case having an accommodating space in which the plurality of battery cells 04 are accommodated.

Reference is made to fig. 9 and 10, which are battery packs as one example. A battery case and a plurality of battery modules 05 disposed in the battery case may be included in the battery pack. The battery box includes an upper box body 06 and a lower box body 07, and the upper box body 06 can be covered on the lower box body 07 and forms a closed space for accommodating the battery module 05. The plurality of battery modules 05 may be arranged in the battery case in any manner.

[ electric device ]

The embodiment of the application also provides an electric device, which comprises the battery.

The powered device may include, but is not limited to, a cell phone, tablet, notebook computer, electric toy, electric tool, battery car, electric car, ship, spacecraft, and the like. Among them, the electric toy may include fixed or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric plane toys, and the like, and the spacecraft may include planes, rockets, space planes, and spacecraft, and the like. As the electricity consumption device, a battery cell, a battery module, or a battery pack in the battery may be selected according to the use requirements thereof.

Fig. 11 is an electric device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or the like. To meet the high power and high energy density requirements of the power device for the battery, a battery pack or battery module may be employed.

Embodiments of the present application are described in detail below. The following examples are illustrative only and are not to be construed as limiting the application. The examples are not to be construed as limiting the specific techniques or conditions described in the literature in this field or as per the specifications of the product. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

[ Ga-doped sodium-ion layered oxide cathode Material ]

Example A1

[ sodium-ion layered oxide cathode Material ]

The present embodiment provides a sodium ion layered oxide positive electrode material having a chemical formula of NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 。

The preparation method of the sodium ion layered oxide positive electrode material comprises the following steps:

(1) Na is mixed with ₂ CO ₃ 、NiO、Fe ₂ O ₃ 、Mn ₂ O ₃ 、CuO、Ga ₂ O ₃ According to the mole ratio Na: ni: fe: mn: cu: ga is 1:0.2:0.29:0.4:0.1:0.01 a total of 30g of sample was weighed. The obtained sample was previously ground in an agate mortar and then added to a planetary ball mill to ball mill for 1 hour, thereby obtaining a precursor mixture.

(2) Uniformly placing the obtained precursor mixture in an open crucible, then heating the precursor mixture from room temperature (25 ℃) to 950 ℃ in a muffle furnace at a heating rate of 5 ℃/min, keeping the precursor mixture at the constant temperature of 950 ℃ for 15 hours, and naturally cooling to obtain the sodium ion layered oxide anode material NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 。

[ sodium ion Battery ]

The sodium ion layered oxide positive electrode material of the embodiment is adopted as a positive electrode active material to prepare a positive electrode plate, and the positive electrode plate, the negative electrode plate, the electrolyte and the isolating film are assembled together to form the sodium ion battery.

1) Positive electrode plate

The sodium ion layered oxide cathode material, conductive agent carbon black, binder polyvinylidene fluoride (PVDF) and N-methyl pyrrolidone (NMP) are mixed according to the mass ratio of 60:5:5:30, stirring and mixing uniformly to obtain positive electrode slurry; thereafter according to 20mg/cm ² The coating amount of the anode slurry is uniformly coated on an anode aluminum foil current collector, and then the anode sheet is obtained through drying, cold pressing and cutting.

2) Negative pole piece

The negative electrode plate is an active thin metal sodium plate with the diameter of 16mm and the thickness of 2 mm.

3) Electrolyte solution

In an argon atmosphere glove box (H ₂ O<0.1ppm，O ₂ <0.1 ppm), mixing organic solvent Ethylene Carbonate (EC)/methyl ethyl carbonate (EMC) uniformly according to a volume ratio of 3/7, adding 12.5wt% NaPF ₆ Dissolving sodium salt in organic solventAnd (3) uniformly stirring in a solvent to obtain the electrolyte.

4) Isolation film

Glass fiber having a thickness of 500 μm was used as a separator.

5) Sodium ion battery

And sequentially stacking the positive electrode plate, the isolating film and the negative electrode plate, winding to form an electrode assembly, loading the electrode assembly into a packaging shell, adding electrolyte, and carrying out the processes of packaging, formation, standing and the like to obtain the sodium ion battery.

Example A2

This embodiment is different from embodiment A1 in that: the chemical formula of the sodium ion layered oxide positive electrode material is NaNi _0.2 Fe _0.2 Mn _0.4 Cu _0.05 Ga _0.15 O ₂ ；Na ₂ CO ₃ 、NiO、Fe ₂ O ₃ 、Mn ₂ O ₃ 、CuO、Ga ₂ O ₃ According to the mole ratio Na: ni: fe: mn: cu: ga is 1:0.2:0.2:0.4:0.05:0.15 weight.

Example A3

This embodiment is different from embodiment A1 in that: the chemical formula of the sodium ion layered oxide positive electrode material is NaNi _0.2 Fe _0.3 Mn _0.4 Cu _0.09 Ga _0.01 O ₂ ；Na ₂ CO ₃ 、NiO、Fe ₂ O ₃ 、Mn ₂ O ₃ 、CuO、Ga ₂ O ₃ According to the mole ratio Na: ni: fe: mn: cu: ga is 1:0.2:0.3:0.4:0.09:0.01 weight.

Example A4

This embodiment is different from embodiment A1 in that: the chemical formula of the sodium ion layered oxide positive electrode material is NaNi, wherein Cu is replaced by Zn with equal molar quantity _0.2 Fe _0.29 Mn _0.4 Zn _0.1 Ga _0.01 O ₂ The method comprises the steps of carrying out a first treatment on the surface of the CuO is replaced with ZnO.

Example A5

This embodiment is different from embodiment A1 in that: cu is replaced by Mg with equal molar quantity, and the proportion of each element is adjusted at the same time, so that the sodium ion layered oxide anode material Has the chemical formula of NaNi _0.2 Fe _0.30 Mn _0.4 Mg _0.05 Ga _0.05 O ₂ The method comprises the steps of carrying out a first treatment on the surface of the Meanwhile, the CuO in the raw material is replaced by MgO.

Example A6

This embodiment is different from embodiment A1 in that: the proportion of Ni is reduced, so that the chemical formula of the sodium ion layered oxide positive electrode material is NaNi _0.1 Fe _0.39 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 。

Example A7

This embodiment is different from embodiment A1 in that: the sodium ion layered oxide positive electrode material does not contain Ni, and has a chemical formula of NaFe _0.39 Mn _0.5 Cu _0.1 Ga _0.01 O ₂ 。

Example A8

This embodiment is different from embodiment A1 in that: the sodium ion layered oxide positive electrode material does not contain Cu and has a chemical formula of NaNi _0.39 Fe _0.2 Mn _0.4 Ga _0.01 O ₂ 。

Example A9

This embodiment is different from embodiment A1 in that: increases the proportion of Ni and adaptively adjusts the proportion of each element so that the chemical formula of the sodium ion layered oxide anode material is NaNi _0.25 Fe _0.39 Mn _0.3 Cu _0.05 Ga _0.01 O ₂ 。

Example A10

This comparative example differs from example A1 in that: the Na proportion is reduced, so that the chemical formula of the sodium ion layered oxide positive electrode material is Na _0.7 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 。

Comparative example A1

This comparative example differs from example A1 in that: the sodium ion layered oxide positive electrode material does not contain Ga, and has a specific chemical formula of NaNi _0.2 Fe _0.3 Mn _0.4 Cu _0.1 O ₂ ；Na ₂ CO ₃ 、NiO、Fe ₂ O ₃ 、Mn ₂ O ₃ CuO, molar ratio Na: ni: fe: mn: cu is 1:0.2:0.3:0.4:0.1 weight.

Comparative example A2

This comparative example differs from example A1 in that: ga is replaced by Al with equimolar quantity, and the chemical formula of the sodium ion layered oxide positive electrode material is NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Al _0.01 O ₂ 。

The chemical formulas of the sodium ion layered oxide positive electrode materials in examples A1 to a10, and comparative examples A1 and A2 are summarized in the following table.

The structures of the sodium ion layered oxide cathode materials of examples A1 to a10, and comparative examples A1 and A2 were tested, including particle diameter Dv50, specific surface area, tap density, and compacted density, and the results are shown in the following table.

As can be seen from the table, each of the sodium ion layered oxide cathode materials has a small particle diameter of micrometer scale and a moderate specific surface area, which is advantageous for improving the processability thereof. Meanwhile, each sodium ion layered oxide positive electrode material also shows larger tap density and compaction density, which is beneficial to improving the energy density when the positive electrode plate is manufactured.

XRD analysis tests were performed on the sodium-ion layered oxide cathode materials of examples A1 to A10 and comparative examples A1 and A2 to obtain the interlayer spacing of the (003) plane in each of the sodium-ion layered oxide cathode materialslAnd a space group. Meanwhile, after the sodium ion layered oxide cathode material contacts water, the interlayer spacing of the sodium ion layered oxide cathode material is generally changed, so that the water stability of the sodium ion layered oxide material can be represented by the interlayer spacing change rate, and the smaller the spacing change rate is, the better the water stability is. Layered oxidation of sodium ions The cathode material is soaked in water for 24 hours, and then XRD analysis and test are carried out to obtain the change rate delta of the interlayer spacing of the soaked (003) crystal facel。

In addition, electrochemical performance tests are carried out on the sodium ion batteries assembled in each example and comparative example to obtain the specific capacity C of the sodium ion layered oxide positive electrode material ₀ . The relevant performance test results are shown in fig. 2, 3 and the following table.

Fig. 2 is an X-ray diffraction spectrum before and after immersing the non-Ga-doped sodium-ion layered oxide cathode material of comparative example A1 in water, and fig. 3 is an X-ray diffraction spectrum before and after immersing the non-Ga-doped sodium-ion layered oxide cathode material of example A1 in water. By comparing XRD diffraction peaks of the samples with standard cards of XRD analysis software, it was confirmed that the phase structures of the sodium-ion layered oxide cathode materials of comparative example A1 and example A1 were O3 phases, and the space group was. Fig. 2 shows that, after 24 hours of immersion in water, the (003) diffraction peaks of the sodium-ion layered oxide cathode materials of example A1 and comparative example A1 were shifted in the vicinity of 16.5 ° compared to before immersion, wherein the shift in the position of the (003) diffraction peak of example A1 was significantly smaller than that of comparative example A1. The change in diffraction peak position reflects the change in lattice interlayer spacing, and therefore, the sodium-ion layered oxide cathode material of example A1 has smaller interlayer spacing change after 24 hours of soaking in water, and has better water stability than comparative example A1.

Moreover, after the sodium-ion layered oxide cathode material of comparative example A1 is soaked in water for 24 hours, the intensity of the (003) diffraction peak is weakened, and the sharp shape is changed into a smoother shape, which further shows that the structure of the sodium-ion layered oxide cathode material of comparative example A1 is changed after being soaked in water, and the lattice structure is unstable. However, the (003) diffraction peak intensity of the sodium-ion layered oxide cathode material of example A1 was not decreased, but rather increased, and the sharpness was increased after being immersed under the same conditions, reflecting its excellent water stability.

As can be further seen from the test data of Table A3, the sodium-ion layered oxide cathode materials of examples A1 to A10 show a layer-to-layer spacing change rate of the (003) plane after being immersed in water for 24 hourslAre each less than 1.20% of comparative example A1. Meanwhile, in the sodium-ion layered oxide cathode material of comparative example A2, since Ga was replaced with other element (Al), the rate of change in the interlayer spacing after 24 hours of soaking the sodium-ion layered oxide cathode material in water was led to the following%lCompared with the examples A1 to A10 and the comparative example A1, the water stability is reduced. Therefore, by doping proper Ga, the interlayer spacing change of the sodium ion layered oxide positive electrode material after being soaked in water can be effectively reduced, and the water stability of the sodium ion layered oxide positive electrode material is improved.

In addition, the sodium-ion layered oxide cathode material of each example shows a higher specific capacity, and the degree of decrease in specific capacity is smaller than that under undoped Ga, and can reach the level equivalent to that of the common sodium-ion layered oxide cathode material, reflecting that after Ga is doped in the sodium-ion layered oxide cathode material, excellent high specific capacity can be maintained while improving water stability.

Ta-doped sodium-ion layered oxide cathode Material

Example B1

This embodiment is different from embodiment A1 in that: the chemical formula of the sodium ion layered oxide positive electrode material is NaNi, wherein Ga is replaced by Ta with equal molar quantity _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ ；Ga ₂ O ₃ Replaced by Ta ₂ O ₅ 。

Example B2

This embodiment is different from embodiment B1 in that: the proportion of each element is regulated to lead the chemical formula of the sodium ion layered oxide anode material to be NaNi _0.2 Fe _0.2 Mn _0.4 Cu _0.05 Ta _0.15 O ₂ 。

Example B3

This embodiment is different from embodiment B1 in that: the proportion of each element is regulated to lead the chemical formula of the sodium ion layered oxide anode material to be NaNi _0.2 Fe _0.3 Mn _0.4 Cu _0.09 Ta _0.01 O ₂ 。

Example B4

This embodiment is different from embodiment B1 in that: the chemical formula of the sodium ion layered oxide positive electrode material is NaNi, wherein Cu is replaced by Zn with equal molar quantity _0.2 Fe _0.29 Mn _0.4 Zn _0.1 Ta _0.01 O ₂ 。

Example B5

This embodiment is different from embodiment B1 in that: cu is replaced by Mg with equal molar quantity, and the contrast between elements is adjusted at the same time, so that the chemical formula of the sodium ion layered oxide positive electrode material is NaNi _0.2 Fe _0.30 Mn _0.4 Mg _0.05 Ta _0.05 O ₂ 。

Example B6

This embodiment is different from embodiment B1 in that: increasing the proportion of Ni element to make the chemical formula of the sodium ion layered oxide positive electrode material be NaNi _0.3 Fe _0.19 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 。

Example B7

This embodiment is different from embodiment B1 in that: the proportion of Ni element is reduced, so that the chemical formula of the sodium ion layered oxide positive electrode material is NaNi _0.1 Fe _0.39 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 。

Example B8

This embodiment is different from embodiment B1 in that: the sodium ion layered oxide positive electrode material does not contain Ni, and has a chemical formula of NaFe _0.39 Mn _0.5 Cu _0.1 Ta _0.01 O ₂ 。

Example B9

This embodiment is different from embodiment B1 in that: the sodium ion layered oxide positive electrode material does not contain Fe, as inWhen Cu is replaced by Zn, and the proportion of each element is regulated to lead the chemical formula of the Cu to be NaNi _0.39 Mn _0.5 Zn _0.1 Ta _0.01 O ₂ 。

Example B10

This embodiment is different from embodiment B1 in that: the sodium ion layered oxide positive electrode material does not contain Mn, and has a chemical formula of NaNi _0.45 Fe _0.5 Cu _0.04 Ta _0.01 O ₂ 。

Example B11

This embodiment is different from embodiment B1 in that: the sodium ion layered oxide positive electrode material does not contain Cu and has a chemical formula of NaNi _0.39 Fe _0.2 Mn _0.4 Ta _0.01 O ₂ 。

Example B12

This embodiment is different from embodiment B1 in that: increasing the Na element proportion to lead the chemical formula of the sodium ion layered oxide anode material to be Na _1.03 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 。

Example B13

This embodiment is different from embodiment B1 in that: the Na element proportion is reduced, so that the chemical formula of the sodium ion layered oxide positive electrode material is Na _0.7 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 。

Example B14

This embodiment is different from embodiment B1 in that: the proportion of each element is regulated to lead the chemical formula of the sodium ion layered oxide anode material to be NaNi _0.25 Fe _0.39 Mn _0.3 Cu _0.05 Ta _0.01 O ₂ 。

Comparative example B1

The present comparative example differs from example B1 in that: the Na-ion layered oxide positive electrode material does not contain Ta, and has a specific chemical formula of NaNi _0.2 Fe _0.3 Mn _0.4 Cu _0.1 O ₂ 。

Comparative example B2

Comparative and examplesB1 differs in that: ta is replaced by Al with equal molar quantity, and the chemical formula of the sodium ion layered oxide positive electrode material is NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Al _0.01 O ₂ 。

The chemical formulas of the sodium ion layered oxide positive electrode materials in examples B1 to B14, and comparative examples B1 and B2 are summarized in the following table.

The structures of the sodium ion layered oxide cathode materials of examples B1 to B14, and comparative examples B1 and B2 were tested, including particle size Dv50, specific surface area, tap density, and compacted density, and the results are shown in the following table.

XRD tests were performed on the sodium-ion layered oxide cathode materials of examples B1 to B14 and comparative examples B1 and B2, wherein X-ray diffraction spectra of the sodium-ion layered oxide cathode materials of example B1 before and after 24 hours of immersion in water are shown in FIG. 4. Meanwhile, the sodium-ion layered oxide cathode materials of examples B1 to B14, and comparative examples B1 and B2 showed a change in the interlayer spacing of the (003) plane after 24 hours of immersion in waterlAnd also specific capacity C ₀ As shown in the table below.

As can be seen from fig. 4, similarly to example A1, the sodium-ion layered oxide cathode material of example B1 had a significantly smaller shift in the (003) diffraction peak position around 16.5 ° after 24 hours of immersion in water than that of comparative example B1 (i.e., comparative example A1, fig. 2) without Ta doping, and the (003) diffraction peak intensity was not weakened, but rather significantly enhanced, with an increase in sharpness, indicating that the sodium-ion layered oxide cathode material of example B1 also had better stability than that of comparative example B1, and the effect of water immersion on its structure was small.

Meanwhile, the test data of Table B3 also show that the sodium-ion layered oxide cathode materials of examples B1 to B14 show a rate of change in the interlayer spacing of the (003) plane after 24 hours of immersion in waterlOnly 0.31% -0.56%, much lower than 1.20% of comparative example B1 in which Ta is undoped and comparative example B2 in which Ta is replaced with an improper element (Al). Therefore, by doping proper Ta, the interlayer spacing change of the sodium ion layered oxide positive electrode material after being soaked in water can be effectively reduced, and the water stability of the sodium ion layered oxide positive electrode material is improved.

In addition, the sodium-ion layered oxide cathode materials of examples B1 to B14 show higher specific capacities, and the degree of decrease in specific capacities is smaller than that of undoped Ta, so that the equivalent level of specific capacities of common sodium-ion layered oxide cathode materials can be achieved, reflecting that after Ta is doped in the sodium-ion layered oxide cathode materials, excellent high specific capacities can be maintained while improving water stability.

[ ZR doped sodium ion layered oxide cathode Material ]

Example C1

This embodiment is different from embodiment A1 in that: the chemical formula of the positive electrode material of the layered oxide of sodium ions is NaNi, wherein Ga is replaced by Zr with equal molar quantity _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Zr _0.01 O ₂ ；Ga ₂ O ₃ Replaced by ZrO ₂ 。

Example C2

This embodiment is different from embodiment C1 in that: adjusting the proportion of each element to makeThe chemical formula of the obtained sodium ion layered oxide positive electrode material is NaNi _0.2 Fe _0.2 Mn _0.4 Cu _0.05 Zr _0.15 O ₂ 。

Example C3

This embodiment is different from embodiment C1 in that: the proportion of each element is regulated to lead the chemical formula of the sodium ion layered oxide anode material to be NaNi _0.2 Fe _0.3 Mn _0.4 Cu _0.09 Zr _0.01 O ₂ 。

Example C4

This embodiment is different from embodiment C1 in that: the chemical formula of the sodium ion layered oxide positive electrode material is NaNi, wherein Cu is replaced by Zn with equal molar quantity _0.2 Fe _0.29 Mn _0.4 Zn _0.1 Zr _0.01 O ₂ 。

Example C5

This embodiment is different from embodiment C1 in that: the chemical formula of the sodium ion layered oxide positive electrode material is NaNi, wherein Cu is replaced by Mg with equal molar quantity _0.2 Fe _0.29 Mn _0.4 Mg _0.1 Zr _0.01 O ₂ 。

Example C6

This embodiment is different from embodiment C1 in that: increasing the proportion of Ni element to make the chemical formula of the sodium ion layered oxide positive electrode material be NaNi _0.3 Fe _0.19 Mn _0.4 Cu _0.1 Zr _0.01 O ₂ 。

Example C7

This embodiment is different from embodiment C1 in that: the proportion of Ni element is reduced, so that the chemical formula of the sodium ion layered oxide positive electrode material is NaNi _0.1 Fe _0.39 Mn _0.4 Cu _0.1 Zr _0.01 O ₂ 。

Example C8

This embodiment is different from embodiment C1 in that: the sodium ion layered oxide positive electrode material does not contain Ni, and has a chemical formula of NaFe _0.39 Mn _0.5 Cu _0.1 Zr _0.01 O ₂ 。

Example C9

This embodiment is different from embodiment C1 in that: the sodium ion layered oxide positive electrode material does not contain Cu and has a chemical formula of NaNi _0.39 Fe _0.2 Mn _0.4 Zr _0.01 O ₂ 。

Example C10

This embodiment is different from embodiment C1 in that: the proportion of each element is regulated to lead the chemical formula of the sodium ion layered oxide anode material to be NaNi _0.25 Fe _0.39 Mn _0.3 Cu _0.05 Zr _0.01 O ₂ 。

Example C11

This embodiment is different from embodiment C1 in that: the sodium ion layered oxide anode material does not contain Fe, cu is replaced by Zn, and the proportion of each element is regulated to lead the chemical formula of the material to be NaNi _0.39 Mn _0.5 Zn _0.1 Zr _0.01 O ₂ 。

Example C12

This embodiment is different from embodiment C1 in that: the Na element proportion is reduced, so that the chemical formula of the sodium ion layered oxide positive electrode material is Na _0.7 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Zr _0.01 O ₂ 。

Comparative example C1

This comparative example differs from example C1 in that: the sodium ion layered oxide positive electrode material does not contain Ga, and has a specific chemical formula of NaNi _0.2 Fe _0.3 Mn _0.4 Cu _0.1 O ₂ 。

Comparative example C2

This comparative example differs from example C1 in that: zr is replaced by Al with equal molar quantity, and the chemical formula of the sodium ion layered oxide positive electrode material is NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Al _0.01 O ₂ 。

The chemical formulas of the sodium ion layered oxide positive electrode materials in examples C1 to C12, and comparative examples C1 and C2 are summarized in the following table.

The structures of the sodium ion layered oxide cathode materials of examples C1 to C12, and comparative examples C1 and C2 were tested, including particle size Dv50, specific surface area, tap density, and compacted density, and the results are shown in the following table.

XRD analysis tests were performed on the sodium-ion layered oxide cathode materials of examples C1 to C12 and comparative examples C1 and C2 to obtain the interlayer spacing of the (003) plane in each of the sodium-ion layered oxide cathode materialslAnd a space group. Meanwhile, soaking each sodium ion layered oxide positive electrode material in water for 24 hours, and obtaining the delta of the interlayer spacing change rate of the soaked (003) crystal face through XRD analysis and testl. In addition, electrochemical performance tests are carried out on the sodium ion batteries assembled in the examples C1-C12, the comparative examples C1 and C2, and the specific capacity of the sodium ion layered oxide positive electrode material is obtained.

The results of performance tests of the sodium ion layered oxide cathode materials of examples C1 to C12, and comparative examples C1 and C2 are shown in fig. 5 and the following table.

FIG. 5 is an X-ray diffraction spectrum of a sodium-ion layered oxide cathode material of example C1 before and after immersion in water, having a phase structure of O3 phase and a space group of. Similar to example A1, the (003) diffraction peak position of the sodium-ion layered oxide cathode material of example C1 was significantly less shifted at around 16.5 ° than before soaking compared to comparative example C1 (i.e., comparative example A1, fig. 2), and the (003) diffraction peak intensity thereof was significantly reduced after soaking in water for 24 hours, unlike comparative example C1, indicating that the sodium-ion layered oxide cathode material of example C1 had good stability and the water soaking had less influence on its structure.

Meanwhile, the layer-spacing change rates of examples C1 to C12 were constantlCan be as low as 0.10%, and has good water stability. In contrast, after Zr is not doped or is replaced with Al, the rate of change of the interlayer spacing of the sodium-ion layered oxide positive electrode material after 24 hours of soaking in water is deltalLarger, reflecting its poor water stability. Therefore, the water stability of the material can be obviously improved by doping Zr element in the sodium ion layered oxide positive electrode material.

In addition, the sodium-ion layered oxide cathode materials of examples C1 to C12 show higher specific capacities, and the degree of decrease in specific capacities is smaller than that of undoped Zr, so that the equivalent level of specific capacities of common sodium-ion layered oxide cathode materials can be achieved, reflecting that after doping Zr and other elements in the sodium-ion layered oxide cathode materials, the water stability is improved, and meanwhile, excellent high specific capacities can be maintained.

The method comprises the following steps: the specific test method for the various performances is as follows:

(1) Rate of change in layer spacinglSpace group

1) Grinding a sample to be tested in an agate mortar in a drying room or a glove box, sieving with a 350-mesh sieve, taking a proper amount of the sieved sample, and filling the sieved sample into the middle of a groove of a sample frame to enable loose sample powder to be slightly higher than the plane of the sample frame; and (3) taking the glass slide, lightly pressing the surface of the sample, enabling the surface of the sample to be scraped to be consistent with the plane of the frame, and scraping off redundant powder.

After the sample preparation, a Brucker D8A-A25 type X-ray powder diffractometer from Brucker AxS, germany was used to obtain CuK _α The rays being radiation sourcesThe radiation wavelength lambda=1.5406A, the scanning 2 theta angle range is 10-70 degrees, and the scanning speed is 4 degrees/min for testing.

After the test is completed, the angle corresponding to the (003) crystal face is passed through the method according to the Bragg equation 2 lSin θ=λ, and each unit cell of the (003) plane contains three transition metal layers, the interlayer spacing of the (003) plane can be obtainedlThe spatial population of the sample can be confirmed by comparing the XRD diffraction peaks of the sample with standard cards of the XRD analysis software.

2) Rate of change in layer spacinglThe sodium ion layered oxide anode material is obtained through soaking test. Specifically, 5g of sodium ion layered oxide positive electrode material is placed in a beaker, 15mL of deionized water is added and vigorously stirred for 1min, after standing for 24h, suction filtration is carried out, and vacuum drying is carried out at 80 ℃ for 12h, so that the soaked sodium ion layered oxide positive electrode material is obtained. The characteristic position change of (003) in the X-ray diffraction spectrum of the sodium ion layered oxide positive electrode material before and after soaking in water for 24 hours was observed using the X-ray powder diffractometer in the above step 1).

And theta' represents the characteristic peak position of the sodium ion layered oxide positive electrode material in the X-ray diffraction spectrum after being soaked in water for 24 hours, and theta represents the characteristic peak position of the sodium ion layered oxide positive electrode material in the X-ray diffraction spectrum before being soaked. According to Bragg equation 2lCalculating sin theta=lambda to obtain the water before and after soakinglAndl' and then calculating the layer spacing change rate delta after 24h of soaking in water l=[（l-l’）/l]*100%。△lSmaller indicates better water stability of the material.

(2) Specific capacity C ₀

After the positive electrode active material is prepared into a secondary battery at 25 ℃, the secondary battery is charged to 4.3V at a constant current density of 10mA/g, and then discharged to 1.5V at a constant current density of 10mA/g, so as to obtain the discharge specific capacity C of the secondary battery ₀ 。

（3）Dv50

Dv50 was determined using a device markov 3000 with reference to GB/T19077-2016/ISO 13320:2009 "particle size distribution laser diffraction method".

(4) Specific surface area

The specific surface area of the solid matter was measured by a nitrogen adsorption specific surface area analysis test method by a Tri-Star 3020 type specific surface area pore size analysis tester from Micromeritics, america, and calculated by BET (Brunauer Emmett Teller), with reference to GB/T19587-2017, BET method for gas adsorption determination.

(5) Tap density

Reference is made to GB/T5162-2021 determination of tap Density of Metal powder, determination is carried out by means of a tap Density Meter.

(6) Density of compaction

Reference is made to appendix L of GB/T24533-2019, method for testing compacted Density of powder, which is obtained by testing with a compaction densitometer.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application, and are intended to be included within the scope of the appended claims and description. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims

1. A sodium ion layered oxide positive electrode material is characterized by comprising Na _x Ni _a Fe _b Mn _c M ¹ _d M ² _e O _2-p A _p Wherein 0.6<x<1.2，0≤a，0≤b，0≤c，0≤d，0<e≤0.15，a+b+c+d+e=1，0<(a+b)/(c+d+e) is more than or equal to 19,0 and p is more than or equal to 0.1; the M is ¹ Comprising groups IA to VA, IB to VIIBOne or more elements, said M ² Comprises one or more elements of Ga and Ta, wherein the A comprises one or more nonmetallic elements of VIA groups and VIIA groups.

2. The sodium ion layered oxide cathode material according to claim 1, wherein the M ¹ Including one or more of Cu, li, ti, K, nb, mg, ca, mo, zn, cr, W, bi, sn, ge, al, si, P, B.

3. The sodium ion layered oxide cathode material of claim 1, wherein a comprises one or more of F, cl, S.

4. A sodium ion layered oxide cathode material according to any one of claims 1 to 3, wherein 0.01.ltoreq.e.ltoreq.0.15.

5. The sodium ion layered oxide cathode material according to claim 4, wherein e is 0.1.ltoreq.e.ltoreq.0.15.

6. A sodium ion layered oxide cathode material according to any one of claims 1 to 3, wherein 0< (a+b)/(c+d+e) +.1.8.

7. The sodium ion layered oxide cathode material according to claim 6, wherein 0< (a+b)/(c+d+e) +.1.

8. The sodium ion layered oxide cathode material according to any one of claims 1 to 3, wherein 0.ltoreq.a.ltoreq.0.45.

9. The sodium ion layered oxide cathode material according to claim 8, wherein 0.ltoreq.a.ltoreq.0.4.

10. The sodium ion layered oxide cathode material according to any one of claims 1 to 3, wherein 0.ltoreq.b.ltoreq.0.5.

11. The sodium ion layered oxide cathode material according to claim 10, wherein b is 0.19.ltoreq.b.ltoreq.0.39.

12. The sodium ion layered oxide cathode material according to any one of claims 1 to 3, wherein 0.ltoreq.c.ltoreq.0.5.

13. The sodium ion layered oxide cathode material according to any one of claims 1 to 3, wherein 0.ltoreq.d.ltoreq.0.2.

14. The sodium ion layered oxide cathode material according to claim 13, wherein d is 0.ltoreq.d.ltoreq.0.1.

15. A sodium ion layered oxide cathode material according to any one of claims 1 to 3, wherein the M ² The proportion of each element in the sodium ion layered oxide positive electrode material is Ga as follows:

16. a sodium ion layered oxide cathode material according to any one of claims 1 to 3, characterized in that the sodium ion layered oxide cathode material comprises NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.2 Mn _0.4 Cu _0.05 Ga _0.15 O ₂ 、NaNi _0.2 Fe _0.3 Mn _0.4 Cu _0.09 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Zn _0.1 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.3 0Mn _0.4 Mg _0.05 Ga _0.05 O ₂ 、NaNi _0.1 Fe _0.39 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 、NaFe _0.39 Mn _0.5 Cu _0.1 Ga _0.01 O ₂ 、NaNi _0.39 Fe _0.2 Mn _0.4 Ga _0.01 O ₂ 、NaNi _0.25 Fe _0.39 Mn _0.3 Cu _0.05 Ga _0.01 O ₂ 、Na _0.7 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ga _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.2 Fe _0.2 Mn _0.4 Cu _0.05 Ta _0.15 O ₂ 、NaNi _0.3 Fe _0.3 Mn _0.4 Cu _0.09 Ta _0.01 O ₂ 、NaNi _0.2 Fe _0.29 Mn _0.4 Zn _0.1 Ta _0.01 O ₂ 、NaNi _0.2 Fe _0.30 Mn _0.4 Mg _0.05 Ta _0.0 ₅ O ₂ 、NaNi _0.3 Fe _0.19 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.1 Fe _0.39 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、NaFe _0.39 Mn _0.5 Cu _0.1 Ta _0.01 O ₂ 、NaNi _0.39 Mn _0.5 Zn _0.1 Ta _0.01 O ₂ 、NaNi _0.45 Fe _0.5 Cu _0.04 Ta _0.01 O ₂ 、NaNi _0.39 Fe _0.2 Mn _0.4 Ta _0.01 O ₂ 、Na _1.03 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.01 O ₂ 、Na _0.7 Ni _0.2 Fe _0.29 Mn _0.4 Cu _0.1 Ta _0.0 ₁ O ₂ 、NaNi _0.25 Fe _0.39 Mn _0.3 Cu _0.05 Ta _0.01 O ₂ One or more of the following.

17. A sodium ion layered oxide cathode material according to any one of claims 1 to 3, characterized in that the phase structure of the sodium ion layered oxide cathode material comprises one or more of O3 phase, O2 phase, P3 phase.

18. The sodium ion layered oxide cathode material of claim 17, wherein the spatial group of sodium ion layered oxide cathode materials comprises、P63/mmcOne or more of the following.

19. A positive electrode sheet, characterized in that it comprises a positive electrode active layer comprising the sodium ion layered oxide positive electrode material according to any one of claims 1 to 18.

20. A battery comprising the positive electrode sheet of claim 19.

21. An electrical device comprising the battery of claim 20.