Sodium-ion batteries and electrical equipment.

Abstract

Invention details;

Description

Sodium ion batteries and electrical equipment

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 27, 2023, with application number 202310771185.5 and application name “Sodium Ion Batteries and Electrical Equipment”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery manufacturing technology, and in particular to a sodium ion battery and electrical equipment. Background Art

[0003] With the development of new energy technologies, energy storage batteries are rapidly gaining popularity. Sodium, due to its abundant reserves in the Earth's crust, widespread distribution, low price, and the ability to leverage existing lithium battery processing conditions, holds great promise for its application. Tunnel-type oxide materials offer advantages such as abundant raw materials, simple synthesis methods, non-toxicity and environmental friendliness, stability to water and oxygen, high structural stability, and high ionic conductivity, making them promising cathode materials for sodium-ion batteries.

[0004] However, when tunnel-type oxide materials are used as the positive electrode materials of batteries, due to the low sodium content of the tunnel-type oxide materials, the sodium ions that can be intercalated and deintercalated during the first cycle of charging of the battery are limited, resulting in extremely low charge and discharge capacity of the battery, which seriously restricts the practical application of tunnel-type oxide materials in sodium-ion batteries.

[0005] Application Contents

[0006] The embodiments of the present application provide a sodium-ion battery and electrical equipment to solve the problem in the related art that when tunnel-type oxide materials are used as the positive electrode materials of the battery, the number of sodium ions that can be intercalated and deintercalated during the first cycle of charging of the battery is limited, resulting in extremely low charge and discharge capacity of the battery, which seriously restricts the practical application of tunnel-type oxide materials in sodium-ion batteries.

[0007] In order to solve the above technical problems, this application is implemented as follows:

[0008] In a first aspect, an embodiment of the present application provides a sodium ion battery, comprising a positive electrode plate, wherein the positive electrode plate comprises: a positive electrode current collector, a first positive electrode material layer disposed on at least one surface of the positive electrode current collector, and a second positive electrode material layer disposed on the first positive electrode material layer;

[0009] The first positive electrode material layer comprises a first positive electrode material, and the first positive electrode material comprises a tunnel oxide;

[0010] The second positive electrode material layer includes a second positive electrode material, and the second positive electrode material includes a P2 and / or O3 type layered oxide.

[0011] Optionally, the molecular formula of the layered oxide contains Na x TMO2, wherein TM contains at least one of Ni, Mn, Fe, Ti, Co, Cu, and Zn, and x satisfies: 0.6 <x<1。

[0012] Optionally, the thickness of the first positive electrode material layer is H1, the thickness of the second positive electrode material layer is H2, and H1 and H2 satisfy: 0.05≤H2 / H1≤0.2

[0013] Optionally, H1 satisfies: 50 μm≤H1≤100 μm.

[0014] Optionally, H2 satisfies: 2.5 μm≤H2≤20 μm.

[0015] Optionally, the tunnel oxide contains sodium and manganese, and the molar ratio of the sodium to the manganese is 0.2 to 0.44.

[0016] Optionally, the tunnel oxide includes Na 0.2 MnO2、Na 0.40 MnO2、Na 0.44 At least one of MnO2.

[0017] Optionally, the compaction density of the positive electrode is K, and K satisfies: 2 mg / cm 3 ≤K≤3mg / cm 3 .

[0018] Optionally, the volume median particle size of the layered oxide is Dv50, and Dv50 satisfies: 3 μm≤Dv50≤15 μm.

[0019] In a second aspect, an embodiment of the present application provides an electrical device, which includes the sodium ion battery described in the first aspect above.

[0020] In an embodiment of the present application, a sodium ion battery includes a positive electrode plate, wherein the positive electrode plate includes: a positive electrode current collector, a first positive electrode material layer disposed on at least one surface of the positive electrode current collector, and a second positive electrode material layer disposed on the first positive electrode material layer. The first positive electrode material layer and the second positive electrode material layer can be carried by the current collector, and the current collector layer can also serve as a carrier for electron collection and conduction in the positive electrode plate, thereby realizing the process of converting chemical energy into electrical energy. Among them, the first positive electrode material layer contains a first positive electrode material, and the second positive electrode material layer contains a second material, that is, the second positive electrode material is disposed on the first positive electrode material. Since the first positive electrode material contains a tunnel-type oxide and the second positive electrode material contains a P2 and / or O3 type layered oxide, the P2 and / or O3 type layered oxide and the tunnel-type oxide are stacked on at least one surface of the current collector to form a positive electrode plate. Both the tunnel-type oxide and the layered oxide can provide sodium ions during charging. Since the sodium content of the layered oxide is relatively high, the arrangement of the layered oxide can enable the positive electrode plate to have more sodium ions that can be intercalated and deintercalated.

[0021] That is, in the sodium ion battery provided in the embodiment of the present application, since the positive electrode plate also includes a second positive electrode material layer containing a second positive electrode material, when the sodium ion battery is charged for the first cycle, in addition to the first positive electrode material layer, the second positive electrode material layer can also provide additional sodium ions, so that more sodium ions can be intercalated and deintercalated in the sodium ion battery, thereby enabling the sodium ion battery to have a higher discharge capacity, thereby achieving an improvement in the charge and discharge capacity of the sodium ion battery when a tunnel-type oxide is used as the positive electrode material.

[0022] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] FIG1 is a schematic structural diagram of a positive electrode sheet provided in an embodiment of the present application.

[0025] Description of reference numerals:

[0026] 100: positive electrode plate; 10: first positive electrode material layer; 20: second positive electrode material layer; 30: positive electrode current collector. Specific embodiments

[0027] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0028] As shown in Figure 1, the sodium ion battery includes a positive electrode plate 100, which includes: a positive electrode current collector 30, a first positive electrode material layer 10 arranged on at least one surface of the positive electrode current collector 30, and a second positive electrode material layer 20 arranged on the first positive electrode material layer 10; the first positive electrode material layer 10 includes a first positive electrode material, and the first positive electrode material includes a tunnel-type oxide; the second positive electrode material layer 20 includes a second positive electrode material, and the second positive electrode material includes a P2 and / or O3 type layered oxide.

[0029] In an embodiment of the present application, a sodium ion battery includes a positive electrode sheet 100, wherein the positive electrode sheet 100 includes: a positive electrode current collector 30, a first positive electrode material layer 10 disposed on at least one surface of the positive electrode current collector 30, and a second positive electrode material layer 20 disposed on the first positive electrode material layer 10. The first positive electrode material layer 10 and the second positive electrode material layer 20 can be carried by the current collector, and the current collector can also serve as a carrier for electron collection and conduction in the positive electrode sheet 100, thereby realizing the process of converting chemical energy into electrical energy. Among them, the first positive electrode material layer 10 contains a first positive electrode material, and the second positive electrode material layer 20 contains a second positive electrode material, that is, the second positive electrode material is disposed on the first positive electrode material. Since the first positive electrode material contains a tunnel-type oxide and the second positive electrode material contains a P2 and / or O3 type layered oxide, the P2 and / or O3 type layered oxide and the tunnel-type oxide are stacked on at least one surface of the current collector to form the positive electrode sheet 100. Both the tunnel-type oxide and the layered oxide can provide sodium ions during charging. Since the sodium content of the P2 and / or O3 type layered oxides is relatively high, the provision of the P2 and / or O3 type layered oxides can enable the positive electrode plate 100 to have more sodium ions that can be intercalated and deintercalated.

[0030] That is, in the sodium ion battery provided in the embodiment of the present application, since the positive electrode plate 100 also includes the second positive electrode material layer 20 containing the second positive electrode material, when the sodium ion battery is charged for the first cycle, in addition to the first positive electrode material layer 10, the second positive electrode material layer 20 can also provide additional sodium ions, so that there are more sodium ions that can be intercalated and deintercalated in the sodium ion battery, thereby enabling the sodium ion battery to have a higher discharge capacity, thereby achieving an improvement in the charge and discharge capacity of the sodium ion battery when the tunnel-type oxide is used as the positive electrode material.

[0031] The electrochemical performance of sodium-ion batteries depends primarily on the structure and properties of the electrode materials. It is generally believed that the properties of the cathode material (such as specific capacity, voltage, and cyclability) are key factors affecting the energy density, safety, and cycle life of sodium-ion batteries. Currently studied cathode materials for sodium-ion batteries primarily include transition metal oxides, Prussian blue compounds, and polyanionic compounds. Transition metal oxides can be divided into tunnel-type oxides and layered oxides. When the sodium content is high, a layered structure is generally dominant, consisting primarily of stacked transition metal layers arranged side-by-side, with sodium ions located between the layers, forming an alternating layered structure. When the sodium content in the oxide is low, oxides with three-dimensional tunnel structures are dominant, and tunnel-type oxides have tunnels. Therefore, layered oxides have a higher sodium content than tunnel-type oxides, providing more sodium ions that can be intercalated and deintercalated into the negative electrode. During discharge, the unique tunnel structure of the tunnel-type oxide can accommodate additional sodium ions, thereby preventing excessive sodium ions from intercalating into the second cathode material layer 20 and disrupting its structural stability, thus preventing the poor stability of the layered oxide from affecting the operation of the sodium-ion battery.

[0032] The positive electrode current collector 30 has two opposing surfaces, and the first positive electrode material layer 10 is disposed on at least one surface of the positive electrode current collector 30. The first positive electrode material layer 10 may be disposed on one of the two opposing surfaces of the positive electrode current collector 30, or the first positive electrode material layer 10 may be disposed on both surfaces of the positive electrode current collector 30. When the first positive electrode material layer 10 is disposed on both surfaces of the positive electrode current collector 30, the second positive electrode material layer 20 may be disposed on the first positive electrode material layer 10 on one of the surfaces, or on the first positive electrode material layer 10 on both surfaces.

[0033] It should be noted that the second cathode material includes P2 and / or O3-type layered oxides. Specifically, the second cathode material may include P2-type layered oxides (or can be referred to as P2-phase layered oxides). P2-type layered oxides contain more Na+ vacancies and relatively low Na+ diffusion barriers, and usually exhibit good kinetic performance; or it can be O3-type layered oxides (or can be referred to as O3-phase layered oxides). O3-type layered oxides have a higher sodium content and can provide a higher charge-discharge capacity; or, it can also include both P2-type layered oxides and O3-type layered oxides. At this time, the second cathode material may include P2 / O3 heterophase layered metal oxides (or can be referred to as P2 / O3 mixed-phase layered oxides, P2 / O3 composite-phase layered oxides). Compared with single-phase materials, P2 / O3 heterophase layered metal oxides can improve the overall performance of the material to a certain extent. For example, it can improve the problem that the sodium content of P2-phase layered oxides is less than that of O3-phase layered oxides, and there are often violent phase changes and poor structural stability after deep sodiation, and it can also improve the problem of poor rate performance of O3-phase layered oxides to a certain extent.

[0034] It should also be noted that sodium-ion batteries also follow the intercalation / deintercalation working principle. Specifically, during the charging process, sodium ions are deintercalated from the cathode and intercalated into the anode. The more sodium ions intercalated into the anode, the higher the charging capacity; during the discharging process, the reverse is true, and the more sodium ions returning to the cathode, the higher the discharging capacity.

[0035] In addition, in some embodiments, the molecular formula of the layered oxide may include Na x TMO2, where TM includes at least one of Ni, Mn, Fe, Ti, Co, Cu, Zn, and x satisfies: 0.6 < x < 1.

[0036] The molecular formula of the layered oxide includes Na x TMO2, where TM is a transition metal and includes at least one of Ni, Mn, Fe, Ti, Co, Cu, Zn. x satisfies: 0.6 < x < 1. In the case where x satisfies this range, the sodium content in the layered oxide is relatively high, and more sodium ions can be provided during charging, which has a better effect on improving the charge-discharge capacity of sodium-ion batteries.

[0037] TM contains at least one of Ni, Mn, Fe, Ti, Co, Cu, and Zn, that is, TM contains one or more transition metals. When TM is one metal, TM can be one of Ni, Mn, Fe, Ti, Co, Cu, and Zn. At this time, the subscript of TM in the molecular formula is 1; when TM is multiple metals, TM can be multiple of Ni, Mn, Fe, Ti, Co, Cu, and Zn. At this time, the subscript of TM in the molecular formula is 1. It can be understood that the sum of the subscripts of multiple metals is 1. For example, when TM contains Co and Mn, the subscript of Co can be 0.5 and the subscript of Mn can be 0.5; or the subscript of Co can be 0.33 and the subscript of Mn can be 0.67; when TM contains Co, Mn, and Ti, the subscript of Co is 0.5, the subscript of Mn is 0.33, and the subscript of Ti is 0.17. The specific elements of TM in the molecular formula are not specifically limited in the embodiments of the present application.

[0038] It should be noted that for single-phase layered oxides, when 0.7 < x < 1.0, the layered oxide is an O3-type layered oxide; when 0.44 < x ≤ 0.7, the layered oxide is a P2-type layered oxide, which has open prismatic channels and thus has high ionic conductivity and high structural stability. In the embodiments of the present application, setting 0.6 < x < 1 can make the sodium content in the second material layer relatively high, and avoid the problem that when the second material contains a single phase of P2-type layered oxide, the improvement effect on the charge-discharge performance of the sodium-ion battery is poor due to the relatively low sodium content.

[0039] In some embodiments, the tunnel-type oxide contains sodium and manganese elements, and the molar ratio of the sodium element to the manganese element is 0.2 to 0.44. For example, the molar ratio of the sodium element to the manganese element can be 0.2, 0.25, 0.3, 0.3, 0.4, 0.44, or a range composed of any two of the above values.

[0040] In addition, in some embodiments, the tunnel-type oxide may contain Na 0.44 MnO2. Na 0.44 MnO2 has a unique double-tunnel structure, that is, it has unique S-type and pentagonal tunnels, which is conducive to the migration of Na ions. Moreover, Na 0.44 MnO2 has good material stability and good cycling performance, can well accommodate the sodium ions deintercalated from the layered oxide, and can avoid excessive sodium ions from embedding into the surface material and damaging its structural stability, that is, it is beneficial to maintaining the structural stability of the second positive electrode material. And, Na 0.44 MnO2 is coated on the surface with Na xTMO2 does not change its structural characteristics, that is, it still has low alkalinity, good environmental stability and excellent structural stability, and can still maintain the application advantages of low cost, easy processing and high rate performance.

[0041] It should be noted that tunnel oxides include Na 0.2 MnO2、Na 0.40 MnO2、Na 0.44 MnO2, etc. and Na 0.40 Compared with MnO2, Na 0.44 MnO2 has higher capacity, better cycle stability and less structural evolution during charge and discharge, showing better air and electrochemical stability, which can better reduce the cost of sodium ion batteries and improve the high rate performance of sodium ion batteries. Of course, the tunnel oxide can also be other structures, such as Na 0.40 MnO2, a material with good electrochemical activity, can also be used as the material of the first positive electrode material layer 10. Of course, the tunnel oxide can also have other structures and other molecular formulas, which are not specifically limited in this embodiment of the present application.

[0042] In addition, in some embodiments, the Na in the first positive electrode material layer 10 0.44 MnO2 can be in the form of nanorods, Na 0.44 The length of MnO2 is L1, Na 0.44 The diameter of MnO2 is D1, L1 satisfies: 2μm≤L1≤5μm, D1 satisfies: 100nm≤D1≤400nm; or, Na in the first positive electrode material layer 10 0.44 MnO2 can be in the form of nanoribbons, Na 0.44 The length of MnO2 is L2, and the length of Na 0.44 The width of MnO2 is L3, Na 0.44 The thickness of MnO2 is L4, L2 satisfies: 6μm≤L2≤10μm, L3 satisfies: 50nm≤L3≤200nm, and L4 satisfies: 20nm≤L4≤80nm.

[0043] Na 0.44 The size of MnO2 will affect the processing difficulty, coating uniformity, and electrochemical performance of the sodium ion battery of the first positive electrode material layer 10. 0.44 When MnO2 is too large, 0.44 When MnO2 is used to prepare the first positive electrode material slurry, the stability of the slurry is relatively poor. When the first positive electrode material is coated on the current collector to form the first positive electrode material layer 10, the consistency of the first positive electrode material layer 10 is also poor, and uneven coating of the current collector may occur, and the film may even be punctured, causing a short circuit in the battery. 0.44If MnO2 is too small, the processing requirements are high, it is difficult to process, and the production cost will increase. 0.44 When MnO2 is in the form of nanorods and nanobelts, Na 0.44 The size of MnO2 is set within a certain range, which can make Na 0.44 The size of MnO2 is appropriate to avoid the above-mentioned Na 0.44 Problems caused by MnO2 being too large or too small.

[0044] In addition, in some embodiments, as shown in FIG1 , the thickness of the first positive electrode material layer 10 is H1 , and the thickness of the second positive electrode material layer 20 is H2 , and H1 and H2 may satisfy: 0.05≤H2 / H1≤0.2.

[0045] The thickness of the first positive electrode material layer 10 is H1, and the thickness of the second positive electrode material layer 20 is H2. H1 and H2 satisfy 0.05≤H2 / H1≤0.2, that is, the ratio of the thickness of the second positive electrode material layer 20 to the thickness of the first positive electrode material layer 10 is between 0.05 and 0.2. The thickness of the second positive electrode material layer 20 can be set according to the thickness of the first positive electrode material layer 10, or the thickness of the first positive electrode material layer 10 can be set according to the thickness of the second positive electrode material layer 20. When H1 and H2 satisfy 0.05≤H2 / H1≤0.2, the second positive electrode material layer 20 can provide more sodium ions, which has a better effect of compensating for the sodium content of the positive electrode sheet 100, and the first positive electrode material layer 10 can also accommodate additional sodium ions during discharge, which is beneficial to maintaining the structural stability of the second positive electrode material.

[0046] It should be noted that H2 / H1 can specifically be any value between 0.05 and 0.2 or a range consisting of any two values, for example, it can be 0.05, 0.06, 0.09, 0.1, 0.12, 0.15, 0.18, 0.2, 0.1-0.15, etc. The specific value of H2 / H1 is not specifically limited in the embodiments of the present application.

[0047] It should also be noted that the mass of the first positive electrode material layer 10 is M1, and the mass of the second positive electrode material layer 20 is M2. M1 and M2 can satisfy: 5%≤M2 / M1≤20%. When the first positive electrode material layer 10 and the second positive electrode material layer 20 are arranged by coating, the mass of the first positive electrode material layer 10 and the second positive electrode material layer 20 can be controlled. The positive electrode sheet 100 obtained by coating with this mass ratio can satisfy 0.05≤H2 / H1≤0.2, which is convenient for controlling the thickness of the first positive electrode material layer 10 and the thickness of the second positive electrode material layer 20.

[0048] In addition, in some embodiments, H1 may satisfy: 50 μm≤H1≤100 μm.

[0049] The thickness H1 of the first positive electrode material layer 10 can specifically satisfy 50μm≤H1≤100μm, that is, the thickness of the first positive electrode material layer 10 is in the range of 50μm to 100μm. Within this range, the capacity of the positive electrode plate 100 can be larger, and at the same time, it can avoid affecting the subsequent plate rolling process, and can better ensure the performance consistency of the battery plate.

[0050] It should be noted that H1 can specifically be 50 μm, 60 μm, 80 μm, 95 μm, 100 μm, or a range consisting of any two of these values. The specific value of H1 is not specifically limited in this embodiment of the present application.

[0051] In this embodiment, the value of H2 can be determined according to H1. For example, when H1 is 100 μm and H2 / H1=0.1, H2 is 10 μm.

[0052] In addition, in some embodiments, H2 may satisfy: 2.5 μm≤H2≤20 μm.

[0053] The thickness H2 of the second positive electrode material layer 20 can specifically satisfy 2.5 μm ≤ H2 ≤ 20 μm, that is, the thickness of the second positive electrode material layer 20 is within the range of 2.5 μm to 20 μm. Within this range, the second positive electrode material layer 20 can provide additional sodium ions that can be intercalated and deintercalated, thereby improving the charge and discharge capacity of the sodium ion battery. However, the structure of the second positive electrode material in the second positive electrode material layer is more unstable than that of the first positive electrode material. The provision of the second positive electrode material slightly reduces the cycle performance of the formed sodium ion battery. Since the thickness of the second positive electrode material layer 20 is less than or equal to 20 μm, the cycle performance of the sodium ion battery can also be higher, which can meet the battery's usage requirements and avoid a significant reduction in the cycle performance of the sodium ion battery.

[0054] It should be noted that H2 can specifically be 2.5μm, 3μm, 4μm, 10μm, 15μm, 20μm or a range consisting of any two of these values. The specific value of H2 is not specifically limited in this embodiment of the application.

[0055] In this embodiment, the value of H1 can be determined according to H2. For example, when H2 is 5 μm and H2 / H1=0.05, H2 is 100 μm.

[0056] In addition, in some embodiments, the surface density of the positive electrode sheet 100 is δ, and δ can meet the following requirements: 3 mg / cm 2 ≤δ≤10mg / cm 2 .

[0057] Because the lower the surface density of the positive electrode sheet 100, the thickness of the positive electrode sheet 100 can be made smaller, reducing the movement distance of the sodium ions, and the changes caused by the continuous insertion and removal of sodium ions during charging and discharging on the structure of the positive electrode sheet 100 are also smaller, the cycle performance is better, and the capacity retention rate is higher. When the surface density is large, the interface resistance increases, and it is not easy for sodium ions to escape from the material, which can easily cause polarization and thus easily lead to capacity attenuation. In the embodiment of the present application, the surface density of the positive electrode sheet 100 is δ, and δ satisfies: 3mg / cm 2 ≤δ≤10mg / cm 2 This can reduce the impact of sodium ion intercalation and deintercalation on the structure of the positive electrode sheet 100, improve the cycle performance of the sodium ion battery, increase the capacity retention rate, and avoid the problem of low capacity of the sodium ion battery caused by a thin positive electrode sheet 100.

[0058] It should be noted that the surface density δ of the positive electrode sheet 100 can be specifically 3 mg / cm 2 , 4mg / cm 2 , 6mg / cm 2 、6.7mg / cm 2 、10mg / cm 2 Or the range consisting of any two values ​​therein, the specific value of δ is not specifically limited in the embodiments of the present application.

[0059] In addition, in some embodiments, the compaction density of the positive electrode sheet 100 is K, and K can satisfy: 2 mg / cm 3 ≤K≤3mg / cm 3 .

[0060] The compaction density of the positive electrode sheet 100 is K, and K satisfies: 2 mg / cm 3 ≤K≤3mg / cm 3 A compaction density within this range can increase the number of conductive channels and bridges in sodium-ion batteries, increasing the active area available for reactions and thus improving the battery's specific capacity. Furthermore, it can also prevent the structure of the active material from being destroyed, which could reduce cycling performance.

[0061] It should be noted that the compaction density K of the positive electrode sheet 100 can be specifically 2 mg / cm 3 , 2.2mg / cm 3 , 2.4mg / cm 3 , 2.6mg / cm 3 , 2.8mg / cm 3 , 3mg / cm 3 Or a range consisting of any two values ​​thereof. The specific value of K is not specifically limited in the embodiments of the present application.

[0062] Among them, the compaction density K = δ / (H1+H2), and the size of the compaction density is related to δ, H1, and H2. When setting the positive electrode plate, these factors can be combined to set.

[0063] In addition, in some embodiments, the volume median particle size of the layered oxide is Dv50, and Dv50 may satisfy: 3 μm≤Dv50≤15 μm.

[0064] The particle size of the layered oxide in the second positive electrode material layer 20 will affect the processing difficulty, coating uniformity, electrochemical performance, etc. of the second positive electrode material layer 20. For example, large-particle material slurry has low viscosity and good fluidity, while small particle size can increase the specific surface area of ​​the second positive electrode material, reduce the diffusion path of sodium ions in the battery, and improve the transmission performance of electrons and sodium ions in the positive electrode plate 100. The present application sets a reference range for the volume median particle size of the layered oxide, where the volume median particle size is Dv50. The particle size is described by referring to the Dv50 value. Half of the volume of the particles in the layered oxide have a diameter less than the Dv50 value, and half of the volume of the particles have a diameter greater than the Dv50 value. This is a common way to describe the particle size distribution. For example, Dv50 = 8 μm, which means that half of the volume of the particles in the layered oxide in the second positive electrode material have a diameter less than 8 μm, and half of the volume of the particles have a diameter greater than 8 μm.

[0065] 3μm≤Dv50≤15μm. Dv50 within this range can make the layered oxide have a smaller particle size, and the transmission path of sodium ions inside the particles of the second positive electrode material is shorter, thereby improving the rate performance of the battery, reducing the positive electrode polarization phenomenon, and improving the capacity retention rate of the battery during the charge and discharge cycle; and, ensuring that the particle size of the layered oxide is not too small, can effectively inhibit the agglomeration between particles in the second positive electrode material, ensure that the positive electrode has high electrochemical performance, and can also avoid the problem of the layered oxide having too small particle size and inconvenience in processing.

[0066] It should be noted that the volume median particle size of the layered oxide is Dv50, which can be 3μm, 5μm, 7μm, 10μm, 15μm or a range consisting of any two values ​​therein. The specific value of Dv50 is not specifically limited in the embodiments of this application.

[0067] It should be noted that the sodium ion battery also includes a negative electrode sheet, a separator and an electrolyte. The positive electrode sheet 100, the negative electrode sheet, the separator and the electrolyte can form a sodium ion battery. Among them, the negative electrode sheet includes a negative electrode active material, the negative electrode active material can include hard carbon, the electrolyte includes an electrolyte salt and a solvent, the electrolyte salt includes at least one of NaPF6 and NaClO4, and the solvent includes one or more of ethylene carbonate (EC), dimethyl carbonate (DMC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC) and propylene carbonate (PC). Among them, the separator can be a polyolefin separator or a glass fiber separator.

[0068] In an embodiment of the present application, a sodium ion battery includes a positive electrode sheet 100, wherein the positive electrode sheet 100 includes: a positive electrode current collector 30, a first positive electrode material layer 10 disposed on at least one surface of the positive electrode current collector 30, and a second positive electrode material layer 20 disposed on the first positive electrode material layer 10. The first positive electrode material layer 10 and the second positive electrode material layer 20 can be carried by the current collector, and the current collector can also serve as a carrier for electron collection and conduction in the positive electrode sheet 100, thereby realizing the process of converting chemical energy into electrical energy. Among them, the first positive electrode material layer 10 contains a first positive electrode material, and the second positive electrode material layer 20 contains a second material, that is, the second positive electrode material is disposed on the first positive electrode material. Since the first positive electrode material contains a tunnel-type oxide and the second positive electrode material contains a P2 and / or O3 type layered oxide, the P2 and / or O3 type layered oxide and the tunnel-type oxide are stacked on at least one surface of the current collector to form the positive electrode sheet 100. Both the tunnel-type oxide and the layered oxide can provide sodium ions during charging. Since the sodium content of the layered oxide is relatively high, the arrangement of the layered oxide can allow the positive electrode plate 100 to have more sodium ions that can be intercalated and deintercalated.

[0069] That is, in the sodium ion battery provided in the embodiment of the present application, since the positive electrode plate 100 also includes the second positive electrode material layer 20 containing the second positive electrode material, when the sodium ion battery is charged for the first cycle, in addition to the first positive electrode material layer 10, the second positive electrode material layer 20 can also provide additional sodium ions, so that there are more sodium ions that can be intercalated and deintercalated in the sodium ion battery, thereby enabling the sodium ion battery to have a higher discharge capacity, thereby achieving an improvement in the charge and discharge capacity of the sodium ion battery when the tunnel-type oxide is used as the positive electrode material.

[0070] In addition, the present invention also provides a method for producing a positive electrode sheet, the method comprising:

[0071] Step 101: Provide a positive electrode current collector.

[0072] In the embodiment of the present application, the positive electrode current collector can be made of aluminum. Sodium and aluminum do not react, so aluminum can be used to make the positive electrode current collector of the positive electrode sheet of the sodium ion battery, which is low in cost. Specifically, the positive electrode current collector can be aluminum foil.

[0073] Step 102: forming a first positive electrode material layer on the positive electrode current collector, wherein the first positive electrode material layer comprises a tunnel oxide.

[0074] In an embodiment of the present application, a first positive electrode material layer comprising a tunnel-type oxide is formed on the positive electrode current collector. The tunnel-type oxide can serve as an active material of the first positive electrode material layer to provide sodium ions that can be intercalated and deintercalated for the sodium ion battery.

[0075] Forming the first positive electrode material layer on the positive electrode current collector may specifically include: preparing a first positive electrode material; coating the first positive electrode material on the positive electrode current collector; and drying the first positive electrode material to form the first positive electrode material layer. Specifically, the first positive electrode material may be prepared first, then coated on the positive electrode current collector; and then dried to form the first positive electrode material layer. Because the first positive electrode material includes a tunnel-type oxide, the first positive electrode material layer may contain a tunnel-type oxide.

[0076] It should be noted that the first positive electrode material can be mixed with a conductive agent, an adhesive, etc. to obtain a first coating slurry, which can be coated on the positive electrode current collector. After the first coating slurry is dried, the first positive electrode material layer can be obtained. This process can be naturally air-dried, or the first coating slurry can be dried at a temperature range of 80°C-120°C, and the drying time is 10-30 minutes.

[0077] In this embodiment, the tunnel oxide is Na 0.44 Taking MnO2 material as an example, the preparation of the first positive electrode material may specifically include: providing a first mixture formed by Na2CO3 and MnCO3, wherein the molar ratio of Na to Mn in the first mixture is 0.46; ball milling the first mixture to obtain a particle mixture; drying the particle mixture to obtain a dried particle mixture; grinding the dried particle mixture to obtain a first powder precursor; calcining the first powder precursor, and cooling to obtain Na 0.44 MnO2 material is the first positive electrode material. Provide conductive agent and adhesive, mix Na 0.44 MnO2 material, conductive agent and adhesive to obtain a first coating slurry, wherein the Na 0.44 The mass ratio of MnO2 material, conductive agent and adhesive is 8:1:1.

[0078] A certain amount of Na2CO3 and MnCO3 can be weighed so that the molar ratio of Na to Mn is 0.46, and the weighed Na2CO3 and MnCO3 are mixed to form a first mixture. The first mixture is ball-milled to obtain a particle mixture. After the particle mixture is dried, the dried particle mixture is ground to obtain a first powder precursor. The first powder precursor is then calcined and cooled to obtain Na 0.44 MnO2 material. When ball milling the first mixture, alcohol can also be added for ball milling. The alcohol is added to facilitate uniform mixing of Na2CO3 and MnCO3, and the alcohol is volatile and will not adhere to the surface of the first mixture or the particle mixture.

[0079] The first mixture may be ball-milled at a speed of 300 r / min for 4 hours. After obtaining the particle mixture, the particle mixture may be dried and ground in an environment of 50° C. to obtain a powder precursor. The first powder precursor may be calcined in a muffle furnace at 800° C. for 9 hours and then removed after cooling.

[0080] Prepare Na 0.44 After MnO2, the first coating slurry can be prepared. Specifically, a conductive agent and an adhesive are provided, and Na 0.44 MnO2 material, conductive agent and adhesive, that is, the first coating slurry is obtained, wherein Na 0.44 The mass ratio of MnO2 material, conductive agent, and adhesive is 8:1:1. The conductive agent can be one or more of acetylene black (ACET), conductive carbon black (CAS), Ketjen Black (KB), carbon nanotubes, and graphene. The adhesive can be one or more of polyvinylidene fluoride (PVDF), hydroxymethyl cellulose (HMC), and styrene-butadiene rubber (E-SBR).

[0081] It should be noted that in the slurry of the first positive electrode material, the Na 0.44 The mass ratio of MnO2 material, conductive agent and adhesive is not limited to 8:1:1. In the first coating slurry, Na 0.44The mass content percentage of MnO2 can be between 80 and 90 wt%, the mass content percentage of the conductive agent can be between 5 and 10 wt%, and the mass content percentage of the binder can be between 5 and 10 wt%. The specific content can be set according to actual needs and is not specifically limited in this embodiment of the present application. For other tunnel-type oxides, such as Na 0.4 MnO2、Na 0.2 MnO2, etc., can be prepared by simply adjusting the molar ratio of Na to Mn.

[0082] Step 103: forming a second positive electrode material layer on the first positive electrode material layer, wherein the second positive electrode material layer comprises a layered metal oxide, wherein the sodium ion layered metal oxide comprises a P2 and / or O3 type layered oxide.

[0083] In an embodiment of the present application, a second positive electrode material layer comprising a P2 and / or O3 type layered oxide is formed on the first positive electrode material layer. The P2 and / or O3 type layered oxide can serve as an active material of the second positive electrode material layer to provide additional deintercalable sodium ions for the sodium ion battery, thereby avoiding the problem of lower charge and discharge capacity of the sodium ion battery due to fewer deintercalable sodium ions in the first positive electrode material.

[0084] Forming the second positive electrode material layer on the first positive electrode material layer may specifically include: preparing a second positive electrode material; coating the second positive electrode material on the first positive electrode material layer; and drying the second positive electrode material to form the second positive electrode material layer. Specifically, the second positive electrode material may be prepared first, then coated onto the first positive electrode material layer, and the second positive electrode material layer may be dried to form the second positive electrode material layer. Because the second positive electrode material comprises a P2 and / or O3-type layered oxide, the second positive electrode material layer can contain layered oxides with a high sodium content, thereby enabling the second positive electrode material layer to also provide sodium ions to the negative electrode.

[0085] It should be noted that when coating the second positive electrode material, the second positive electrode material, the conductive agent and the adhesive can be mixed to obtain a second coating slurry, which can be coated on the first positive electrode material. The second coating slurry can be dried to obtain a second positive electrode material layer. This process can be naturally air-dried, or the second coating slurry can be dried at a temperature range of 80°C-120°C for 10-30 minutes.

[0086] In this embodiment, the layered oxide is Na 2 / 3 Ni 1 / 3 Mn 2 / 3Taking O2 material as an example, the preparation of the second positive electrode material may specifically include: providing a second mixture formed by Na2CO3, NiO and MnO2, wherein the molar ratio of Na, Ni and Mn in the second mixture is 2:1:1; stirring the second mixture to obtain a second powder precursor; sintering the second powder precursor, and obtaining a sodium ion layered metal oxide material after cooling.

[0087] A certain amount of Na2CO3, NiO and MnO2 can be weighed so that the molar ratio of Na, Ni and Mn is 2:1:1, and the weighed Na2CO3, NiO and MnO2 are mixed to form a second mixture. The second mixture is stirred to obtain a second powder precursor, and then the second powder precursor is sintered to obtain Na after cooling. 2 / 3 Ni 1 / 3 Mn 2 / 3 When ball milling the second mixture, alcohol can also be added for ball milling. The alcohol is added to facilitate uniform mixing of Na2CO3 and MnCO3, and the alcohol is volatile and will not adhere to the surface of the second mixture or the particle mixture.

[0088] After obtaining the second mixture, the second mixture can be stirred under vacuum at room temperature, and can be stirred for 3 hours at a speed of 300r / min by a stirrer to obtain a second powder precursor. When the second powder precursor is sintered after it is obtained, in order to facilitate the heating of the second powder precursor, the second powder precursor can be pressed into a sheet, and then the sheet-like second powder precursor is sintered. The sintering can be carried out in an air environment at 800°C, and then taken out after cooling to obtain Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 material.

[0089] Prepare Na 2 / 3 Ni 1 / 3 Mn 2 / 3 After O2, the second coating slurry can be prepared. Specifically, a conductive agent and an adhesive are provided, mixed with Na 2 / 3 Ni 1 / 3 Mn 2 / 3O2, a conductive agent, and a binder are added to obtain a second coating slurry, wherein the mass ratio of the sodium ion layered metal oxide material, the conductive agent, and the binder in the second coating slurry is 8:1:1. The conductive agent can be one or more of acetylene black (ACET), conductive carbon black (CAS), Ketjen Black (KB), carbon nanotubes, and graphene, and the binder can be one or more of polyvinylidene fluoride (PVDF), hydroxymethyl cellulose (HMC), and styrene-butadiene rubber (E-SBR).

[0090] It should be noted that, in the embodiment of the present application, only the second positive electrode material is provided as Na 2 / 3 Ni 1 / 3 Mn 2 / 3 Preparation method of O2, for the preparation of other materials, please refer to Na 2 / 3 Ni 1 / 3 Mn 2 / 3 When the layered oxide is other materials, different materials can be mixed to obtain a second mixture. The molar ratio of Na to other transition metals in the second mixture can be set according to the specific molecular formula. For example, for NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 When weighing the O2 material to obtain the second mixture, the molar ratio of Na, Ni, Fe, and Mn in the second mixture can be 3:1:1:1. For other materials, the embodiments of the present application are not listed here one by one.

[0091] Among them, in the second coating slurry, Na in the second coating slurry 2 / 3 Ni 1 / 3 Mn 2 / 3 The mass ratio of O2 material, conductive agent and adhesive is not limited to 8:1:1. In the second coating slurry, Na 2 / 3 Ni 1 / 3 Mn 2 / 3 The mass content percentage of O2 can be between 80 and 90 wt%, the mass content percentage of the conductive agent can be between 5 and 10 wt%, and the mass content percentage of the binder can be between 5 and 10 wt%. The specific content can be set according to actual needs, and the embodiment of the present application does not make specific limitations here.

[0092] It should also be noted that the above preparation process is to prepare Na by a high temperature solid phase method. 0.44 MnO2 materials, Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 material, is Na 0.44 MnO2 materials, Na 2 / 3 Ni 1 / 3 Mn 2 / 3 One of the many preparation methods of O2 materials can also be prepared by other methods, such as Na 0.44 MnO2 material can also be prepared by molten salt method or hydrothermal method. For various preparation methods, the embodiments of this application will not list them one by one here.

[0093] When making the negative electrode sheet, the hard carbon negative electrode material, the conductive agent and the binder can be evenly mixed to prepare a negative electrode sheet slurry, wherein the mass content percentage of the hard carbon negative electrode material can be 80-90wt%, the mass content percentage of the conductive agent can be 5-10wt%, and the mass content percentage of the binder can be 5-10wt%; then, copper foil is used as the negative electrode current collector, the negative electrode sheet slurry is coated on the negative electrode current collector, and the negative electrode sheet is obtained by drying at 80°C for 60 minutes.

[0094] In an embodiment of the present application, the first coating slurry and the second coating slurry are applied in layers to obtain the positive electrode sheet 100, avoiding the method of applying the first coating slurry and the second coating slurry after mixing, and the stability of the obtained positive electrode sheet 100 is also better. Due to the different physical properties of tunnel-type oxides and layered oxides, problems may occur in the stirring process after mixing, such as slurry sedimentation, etc. The different compaction densities of the two will also affect the stability of the electrode sheet during rolling. In addition, the crystal phases of the two materials are also different. It is difficult for the electrode sheet prepared after mixed coating to maintain the stability of their respective structures during charging and discharging. The above problems can be avoided by applying the first coating slurry and the second coating slurry in layers.

[0095] In order to make the application purpose, technical solutions and beneficial effects of this application clearer, the present application is further described below in conjunction with examples. It should be understood that these examples are only used to illustrate this application and are not used to limit the scope of this application.

[0096] Example 1

[0097] (1) Preparation of positive electrode materials:

[0098] Providing a first mixture formed of Na2CO3 and MnCO3, wherein the molar ratio of Na to Mn in the first mixture is 0.46; ball milling the first mixture to obtain a particle mixture; drying the particle mixture to obtain a dried particle mixture; grinding the dried particle mixture to obtain a first powder precursor; calcining the first powder precursor, and cooling to obtain Na 0.44 MnO2 material is the first positive electrode material.

[0099] A second mixture of Na2CO3, Ni(CH3COO)2, and C4H6MnO4 is provided, wherein the molar ratio of Na, Ni, and Mn in the second mixture is 2:1:2, and the second mixture is ball-milled to obtain a particle mixture; the second mixture is stirred to obtain a second powder precursor; the second powder precursor is sintered, and after cooling, a layered metal oxide Na is obtained. 2 / 3 Ni 1 / 3 Mn 2 / 3 O2, to obtain the second positive electrode material.

[0100] (2) Preparation of positive electrode sheet:

[0101] Take aluminum sheet as positive electrode current collector;

[0102] Provide conductive agent and adhesive, mix Na 0.44 MnO2 material, conductive agent and adhesive to obtain a first coating slurry, wherein the Na 0.44 The mass ratio of MnO2 material, conductive agent and adhesive is 8:1:1. The first coating slurry is coated on an aluminum sheet and dried at 80°C for 15 minutes to obtain a first positive electrode material layer, wherein the thickness of the first positive electrode material layer is 50 μm.

[0103] Provide conductive agent and adhesive, mix Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 material, conductive agent and adhesive to obtain a second coating slurry, wherein the Na 2 / 3 Ni 1 / 3 Mn 2 / 3 The mass ratio of the O2 material, conductive agent, and binder was 8:1:1. The second coating slurry was applied to the first positive electrode material layer and dried at 120°C for 30 minutes to obtain a positive electrode sheet coated with the second positive electrode material layer. The thickness of the second positive electrode material layer was 2.5 μm.

[0104] (3) Preparation of negative electrode sheet:

[0105] Take copper foil as the negative electrode current collector,

[0106] A negative electrode slurry is prepared by combining a hard carbon material, a conductive agent, and a binder; wherein the mass ratio of the hard carbon material, the conductive agent, and the binder in the negative electrode slurry is 8:1:1;

[0107] The slurry is coated on the copper foil and dried at 80°C for 60 minutes to obtain the negative electrode sheet.

[0108] (4) Assembly of sodium ion batteries:

[0109] The diaphragm, negative electrode sheet and positive electrode sheet are rolled up in sequence, rolled into a bare roll core by a winding machine, and then undergo hot pressing, tab welding, shell packaging, liquid injection, and chemical synthesis processes to prepare sodium ion square batteries.

[0110] The electrolyte includes an electrolyte salt and a solvent, wherein the electrolyte salt is NaPF6 and the solvent is ethylene carbonate (EC); and the diaphragm is a glass fiber diaphragm.

[0111] The difference between Examples 2 to 7 and Example 1 is that the thickness of the first positive electrode material layer and / or the second positive electrode material layer is different, as shown in Table 1 for details.

[0112] The difference between Examples 8 to 11 and Example 1 is that the particle size Dv50 of the second positive electrode material is different, as shown in Table 1 for details.

[0113] The difference between Examples 12 to 15 and Example 1 is that the compaction density of the positive electrode sheets is different, as shown in Table 1.

[0114] The difference between Examples 16 to 21 and Example 1 is that the first positive electrode material or the second positive electrode material is different, as shown in Table 1 for details.

[0115] The difference between Comparative Example 1 and Example 1 is that the second positive electrode material layer is not provided.

[0116] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, Na 0.44 MnO2、Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2, a conductive agent, and an adhesive are mixed to obtain a coating slurry, which is then coated on an aluminum sheet and dried at 80°C for 15 minutes to obtain a positive electrode material layer with a thickness of 52.5 μm.

[0117] Table 1

[0118] Performance Testing

[0119] First cycle discharge capacity in grams:

[0120] 1) Weigh the mass M of the sodium ion battery;

[0121] 2) Place the sodium ion battery in a room temperature environment (25°C ± 1°C) and fully charge the sodium ion battery using a preset rate;

[0122] 3) fully standby at room temperature, and then discharge at a preset discharge rate to the cut-off voltage V of the sodium ion battery;

[0123] 4) Record the capacity (energy) released by the sodium ion battery during this process, recorded as E1;

[0124] 5) Calculate the first-cycle discharge capacity of the sodium-ion battery = E1 / M.

[0125] The discharge rate indicates the size of the discharge current. The charge and discharge rate (C) = discharge current (mA) / rated capacity (mAh). For example, if a battery with a rated capacity of 1000mAh is charged and discharged at a current of 100mA, the charge and discharge rate is 0.1C.

[0126] In the embodiment of the present application, the first-cycle discharge capacity in grams of the sodium-ion battery can be tested at discharge rates of 0.33C, 1C, and 5C, respectively. That is, in the embodiment of the present application, when testing the first-cycle discharge capacity in grams, the tests are performed at preset discharge rates of 0.1C, 1C, and 5C, respectively. Moreover, in a measurement of the first-cycle discharge capacity in grams, the preset rate used during charging is the same as the preset rate used during discharge.

[0127] 1C cycle performance / circle:

[0128] 1) Charging the sodium ion battery at room temperature;

[0129] 2) After charging is completed, the battery is placed in a room temperature environment and then discharged at a 1C discharge rate to the cut-off voltage V of the sodium ion battery;

[0130] 3) Record the capacity (energy) released by the sodium ion battery during this process, recorded as E2;

[0131] 4) Repeat steps 1 to 3 above and count;

[0132] 5) When E2 is lower than 80% of the initial discharge capacity for two consecutive times, the charge and discharge times are determined based on the count at this time, and the 1C cycle performance is obtained.

[0133] The above performance test method was used to perform performance tests on the batteries of each embodiment, and the obtained data are shown in Table 2 below.

[0134] According to the data in the table below, when the second positive electrode material layer 20 is provided on the first positive electrode material layer 10, the discharge capacity will be improved compared to when the second positive electrode material layer 20 is not provided. Moreover, for the same layered oxide, the thickness of the second positive electrode material layer affects the first-cycle discharge capacity.

[0135] Table 2

[0136] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other.

[0137] Although alternative embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they become aware of the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including alternative embodiments and all changes and modifications that fall within the scope of the present invention.

[0138] The above is a detailed introduction to the technical solution provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. At the same time, for those skilled in the art, according to the principles and implementation methods of the present application, there may be changes in the specific implementation methods and application scope. In summary, the contents of this specification should not be understood as limiting the present application.

[0139] References herein to "one embodiment," "an embodiment," or "one or more embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Furthermore, please note that instances of the phrase "in one embodiment" do not necessarily all refer to the same embodiment.

[0140] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

DEPCT6916 / 12 / 25681. A sodium-ion battery comprising an anode electrode plate in which the anode electrode plate comprises: a current acceptor electrode, a first anode electrode layer arranged on at least one surface of the current acceptor electrode, and a second anode electrode layer arranged on the first anode electrode layer. The first anode electrode layer comprises the first anode electrode material and the first anode electrode material comprises tunnel oxide. The second anode electrode layer comprises the second anode electrode material and the second anode electrode material comprises layered oxide P2 and / or O3.

2. A sodium-ion battery according to claim 1 in which the molecular formula of the layered oxide comprises NaxTMO2 in which TM comprises at least one of Ni, Mn, Fe, Ti, Co, Cu and Zn and x is satisfied with: 0.

6. <x<13.แบตเตอรี่โซเดียม-ไอออนตามข้อถือสิทธิที่1ที่ซึ่งความหนาของชั้นวัสดุอิเล็กโทรดขั้วบวกที่หนึ่งคือH1,ความหนาของชั้นวัสดุอิเล็กโทรดขั้วบวกที่สองคือH2และH1และH2เป็นไปตาม:0.

05. Less than or equal to H2 / H1 less than or equal to 0.

24. Sodium-ion battery according to claim 3 where H1 meets: 50 µm less than or equal to H1 less than or equal to 100 µm.

5. Sodium-ion battery according to claim 3 where H2 meets: 2.5 µm less than or equal to H2 less than or equal to 20 µm.

6. Sodium-ion battery according to claim 1 where the tunnel oxide is composed of sodium and manganese elements and the molar ratio of sodium to manganese is 0.2 to 0.

44.

7. Sodium-ion battery according to claim 1. Claim 1: A sodium-ion battery according to Claim 1 where the tunnel oxide consists of at least one of Na0.2MnO2, Na0.40MnO2, and Na0.44MnO2.

8. A sodium-ion battery according to Claim 1 where the compressive density of the anode electrode is K and K meets: 2 mg / cm³ or less than or equal to K ≤ 3 mg / cm³.

9. A sodium-ion battery according to Claim 1 where the volumetric intermediate particle size of the layered oxide is Dv50 and Dv50 meets: 3 µm or less than or equal to Dv50 ≤ 15 µm. 10.An electrical device incorporating a sodium-ion battery as provided by any of Claims 1 through 9;

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