Sodium ion positive plate and preparation method thereof, sodium ion capacitor and sodium ion battery

Abstract

The invention discloses a sodium ion positive plate and a preparation method thereof, a sodium ion capacitor and a sodium ion battery. The sodium ion positive plate comprises a capacity compensation agent, porous carbon, a sodium ion positive electrode material, a conductive agent, a binder and an auxiliary agent, wherein the capacity compensation agent comprises a positive lithium supplement agent with a first mass percent, and the positive lithium supplement agent is used for reducing the potential of the negative plate containing hard carbon and compensating the irreversible capacity of the negative plate; the index requirements of the positive electrode lithium supplementing agent are as follows: the specific capacity is greater than or equal to 420mAh / g, and the first coulombic efficiency is less than or equal to According to the technical scheme, the high-power characteristic of the sodium ion positive plate is improved, the irreversible capacity of the negative electrode is compensated, the initial coulombic efficiency, the energy density and the cycle life of the sodium ion battery or the capacitor are effectively improved, and the preparation cost of the sodium ion battery or the capacitor is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a sodium ion positive electrode sheet and a preparation method thereof, a sodium ion capacitor and a sodium ion battery. Background Art

[0002] With the rapid popularization of electric vehicles and smart grid technology, sodium-ion batteries are expected to replace lithium-ion batteries for large-scale energy storage applications due to their sustainable resource supply.

[0003] However, the sodium storage negative electrode materials have low initial coulombic efficiency, which restricts the development of high specific energy sodium ion batteries. Pre-sodiumization technology is considered to be the most direct and effective method to compensate for the loss of active sodium in the negative electrode and improve the energy density of the battery, but the sodium-rich materials used for pre-sodiumization of sodium ion batteries have poor stability and high cost.

[0004] Based on this, how to stably improve the energy density, initial coulombic efficiency and cycle life of sodium-ion batteries and reduce costs has become an urgent problem to be solved in the industry. Summary of the invention

[0005] The present invention provides a sodium ion positive electrode sheet and a preparation method thereof, a sodium ion capacitor and a sodium ion battery, so as to stably improve the energy density, initial coulomb efficiency and cycle life of the sodium ion battery and effectively reduce the cost.

[0006] According to one aspect of the present invention, there is provided a sodium ion positive electrode sheet, comprising: a mixed capacity compensator, a sodium ion positive electrode material, porous carbon, a binder and an additive;

[0007] The capacity compensating agent comprises a positive electrode lithium replenishing agent having a first mass percentage, and the positive electrode lithium replenishing agent is used to reduce the potential of the negative electrode sheet containing hard carbon and compensate for the irreversible capacity of the negative electrode sheet; the index requirements of the positive electrode lithium replenishing agent are: specific capacity ≥420mAh / g, first coulombic efficiency ≤40%;

[0008] The porous carbon has the following index requirements: the atomic percentage of carbon atoms is ≥ 92%, the Raman peak intensity ratio ranges from 1.05 to 1.25, and the specific surface area ranges from 1400 to 1700 m 2 / g, the micropore specific surface area contribution value is ≥60%, and the particle size range includes 2.0-5.0um; wherein the Raman peak intensity ratio is the intensity ratio of the D peak to the G peak.

[0009] Optionally, the first mass percentage includes 1% to 9%.

[0010] Optionally, the positive electrode lithium supplement includes a lithium-rich manganese-based material, a lithium-rich nickel-based material and / or a lithium-rich iron-based material.

[0011] Optionally, the sodium ion positive electrode material includes at least one of sodium vanadium phosphate, sodium iron phosphate, sodium iron pyrophosphate, sodium nickel cobalt manganate, sodium nickel iron manganate and Prussian blue.

[0012] Optionally, the porous carbon includes at least one of activated carbon, carbon nanotubes, graphene, carbon nanocages and onion carbon.

[0013] Optionally, the binder includes polyvinylidene fluoride and / or polyacrylic resin, and the auxiliary agent includes at least one of polyvinyl pyrrolidone, polycarbonate, lithium aluminum titanium phosphate and lithium lanthanum zirconate.

[0014] Optionally, the porous carbon has a second mass percentage, the sodium ion positive electrode material has a third mass percentage, the binder has a fourth mass percentage, and the auxiliary agent has a fifth mass percentage;

[0015] The second mass percentage includes 0.5% to 35%, the third mass percentage includes 53% to 96%, the fourth mass percentage includes 1% to 3%, and the fifth mass percentage includes 0.05% to 0.5%.

[0016] According to another aspect of the present invention, a method for preparing a sodium ion positive electrode sheet is provided, comprising:

[0017] uniformly mixing the binder, the additive and the organic solvent to obtain a binder slurry;

[0018] uniformly mixing the conductive agent, the porous carbon and the binder slurry to obtain a conductive agent slurry;

[0019] The capacity compensating agent, the sodium ion positive electrode material and the conductive agent slurry are uniformly mixed to obtain a sodium ion positive electrode slurry;

[0020] The sodium ion positive electrode slurry is applied to the surface of the current collector, and the current collector coated with the sodium ion positive electrode slurry is dried, rolled and sheeted to obtain a sodium ion positive electrode sheet;

[0021] The capacity compensating agent comprises a positive electrode lithium replenishing agent having a first mass percentage, and the positive electrode lithium replenishing agent is used to reduce the potential of the negative electrode sheet containing hard carbon and compensate for the irreversible capacity of the negative electrode sheet; the index requirements of the positive electrode lithium replenishing agent are: specific capacity ≥420mAh / g, first coulombic efficiency ≤40%;

[0022] The porous carbon has the following index requirements: the atomic percentage of carbon atoms is ≥ 92%, the Raman peak intensity ratio ranges from 1.05 to 1.25, and the specific surface area ranges from 1400 to 1700 m 2 / g, the micropore specific surface area contribution value is ≥60%, and the particle size range includes 2.0-5.0um; wherein the Raman peak intensity ratio is the intensity ratio of the D peak to the G peak.

[0023] According to another aspect of the present invention, there is provided a sodium ion capacitor, comprising the sodium ion positive electrode sheet as described in any embodiment of the first aspect.

[0024] According to another aspect of the present invention, there is provided a sodium ion battery, comprising the sodium ion positive electrode sheet as described in any embodiment of the first aspect.

[0025] The sodium ion positive electrode sheet provided by the embodiment of the present invention uses a positive electrode lithium replenisher with a first mass percentage as a capacity compensator. Since the research on positive electrode lithium replenishers is relatively mature and widely used, the positive electrode lithium replenisher has good performance stability and low price. For sodium ion batteries using hard carbon as negative electrode active materials, the positive electrode lithium replenisher is used to prepare sodium ion positive electrode sheets. Compared with the use of positive electrode sodium replenishers to prepare sodium ion positive electrode sheets in related technologies, while reducing the hard carbon potential and broadening the voltage window of the sodium ion battery, the initial coulomb efficiency, energy density and cycle life of the sodium ion battery can be effectively improved, and the preparation cost of the sodium ion battery can be reduced.

[0026] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0028] Figure 1 It is a schematic flow chart of a method for preparing a sodium ion positive electrode sheet provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] The embodiment of the present invention provides a sodium ion positive electrode sheet. The sodium ion positive electrode sheet comprises: a mixed capacity compensator, a sodium ion positive electrode material, porous carbon, a binder and an additive; wherein the capacity compensator comprises a positive electrode lithium replenisher having a first mass percentage, and the positive electrode lithium replenisher is used to reduce the potential of the negative electrode sheet containing hard carbon and compensate for the irreversible capacity of the negative electrode sheet; the index requirements of the positive electrode lithium replenisher are: specific capacity ≥ 420 mAh / g, first coulomb efficiency ≤ 40%;

[0032] The index requirements of porous carbon are: the atomic percentage of carbon atoms ≥92%, the Raman peak intensity ratio ranges from 1.05 to 1.25, the specific surface area ranges from 1400 to 1700 m2 / g, the micropore specific surface area contribution value ≥60%, and the particle size ranges from 2.0 to 5.0 um.

[0033] Specifically, a capacity compensator is added to the positive electrode of the battery to offset the irreversible capacity of the negative electrode of the battery and reduce the potential of the negative electrode. For sodium-ion batteries, the relevant technology generally uses a positive electrode sodium supplement as a capacity compensator. However, the current research on positive electrode sodium supplements for sodium-rich materials is not yet mature. Therefore, the performance stability of the positive electrode sodium supplement is insufficient, which easily leads to the unstable performance of sodium-ion batteries using the positive electrode sodium supplement as a capacity compensator. In addition, since the application of positive electrode sodium supplements has not yet been popularized, the preparation cost of sodium-ion batteries prepared using positive electrode sodium supplements is relatively high. For mature lithium-ion batteries, positive electrode lithium supplements are used as capacity compensators. Since positive electrode lithium supplements have been mature and widely used, and positive electrode lithium supplements have a higher capacity, the performance stability of positive electrode lithium supplements is good and the price is low. Lithium-ion batteries prepared using positive electrode lithium supplements have stable performance and can effectively reduce preparation costs.

[0034] Based on this, since both sodium ion batteries and lithium ion batteries can use hard carbon as the active material in the negative electrode sheet, for the sodium ion battery with a hard carbon negative electrode sheet, in the embodiment of the present invention, a positive electrode lithium replenisher with a first mass percentage is used as a capacity compensator and added to the sodium ion positive electrode sheet. When the sodium ion battery is charged, the positive electrode lithium replenisher irreversibly releases lithium ions into the electrolyte, so that the sodium ions in the electrolyte are embedded in the hard carbon of the negative electrode sheet, which can offset the irreversible capacity of the hard carbon and reduce the potential of the hard carbon, so that the positive electrode can maintain a lower working potential during the charge and discharge process, reduce the side reactions of the positive electrode and the electrolyte, thereby widening the voltage window of the sodium ion battery, reducing the battery's inflation rate, and is beneficial to improving the initial coulomb efficiency and energy density of the sodium ion battery, and can effectively reduce the preparation cost of the sodium ion battery.

[0035] It should be noted that the specific capacity of the positive electrode lithium supplement refers to the lithium storage capacity measured with lithium metal as the reference electrode and the counter electrode. The Raman peak intensity ratio of porous carbon can be expressed as I D / I G , where I D represents the intensity of the D peak, I G It indicates the intensity of peak G. The specific surface area of ​​porous carbon is the specific surface area measured by BET method; the particle size indicates the average particle size of porous carbon powder, i.e. particle size D50.

[0036] The sodium ion positive electrode sheet provided by the embodiment of the present invention uses a positive electrode lithium replenisher with a first mass percentage as a capacity compensator. Since the research on positive electrode lithium replenishers is relatively mature and widely used, the positive electrode lithium replenisher has good performance stability and low price. For sodium ion batteries using hard carbon as negative electrode active materials, the positive electrode lithium replenisher is used to prepare sodium ion positive electrode sheets. Compared with the use of positive electrode sodium replenishers to prepare sodium ion positive electrode sheets in related technologies, while reducing the hard carbon potential and broadening the voltage window of the sodium ion battery, the initial coulomb efficiency, energy density and cycle life of the sodium ion battery can be effectively improved, and the preparation cost of the sodium ion battery can be reduced.

[0037] Optionally, based on the above embodiment, the first mass percentage includes 1% to 9%, and the positive electrode lithium supplement includes a lithium-rich manganese-based material, a lithium-rich nickel-based material and / or a lithium-rich iron-based material.

[0038] Exemplarily, a positive electrode lithium replenisher made of a mature lithium-rich manganese-based material, a lithium-rich nickel-based material and / or a lithium-rich iron-based material is added to the sodium ion positive electrode. During the charge and discharge process, lithium ions are irreversibly released into the electrolyte, so that the sodium ions in the electrolyte are embedded in the hard carbon of the battery negative electrode sheet, thereby reducing the potential of the hard carbon, which is beneficial to improving the initial coulomb efficiency and energy density of the sodium ion battery, and ensuring the performance stability of the sodium ion battery. And the use of a positive electrode lithium replenisher can effectively reduce the preparation cost of a sodium ion battery compared to the use of a positive electrode sodium replenisher. A positive electrode lithium replenisher with a first mass percentage of 1% to 9% is added to the sodium ion positive electrode, and its capacity is higher than that of the positive electrode sodium replenisher, which can effectively reduce the potential of the hard carbon. If the mass proportion of the added positive electrode lithium replenisher is too small, the lithium ions contained in the positive electrode lithium replenisher may be insufficient to offset the irreversible capacity of the hard carbon, thereby having a poor effect on improving the initial coulombic efficiency and energy density of the sodium ion battery; if the mass proportion of the added positive electrode lithium replenisher is too large, material waste may occur, and the mass proportion of the sodium ion positive electrode material may affect the life of the sodium ion battery.

[0039] Exemplarily, on the basis of the above embodiments, the sodium ion positive electrode sheet further includes a sodium ion positive electrode material and porous carbon. Among them, the sodium ion positive electrode material includes at least one of sodium vanadium phosphate, sodium iron phosphate, sodium iron pyrophosphate, sodium nickel cobalt manganate, sodium nickel iron manganate and Prussian blue. Porous carbon includes at least one of activated carbon, carbon nanotubes, graphene, carbon nanocages and onion carbon. The binder includes polyvinylidene difluoride (PVDF) and / or polyacrylic resin, and the auxiliary agent includes polyvinylpyrrolidone (PVP), polycarbonate (PC), lithium aluminum titanium phosphate (LATP) and lithium lanthanum zirconate (LLZO).

[0040] Among them, lithium aluminum titanium phosphate and lithium lanthanum zirconate belong to solid electrolytes. For example, using a material mixed with PVP and solid electrolyte as an additive in a sodium ion positive electrode sheet is conducive to enhancing the dispersibility of the positive electrode slurry, reducing the electronic conductivity of the positive electrode sheet, and thus improving the power and life of the sodium ion battery.

[0041] Exemplarily, the porous carbon has a second mass percentage, the sodium ion positive electrode material has a third mass percentage, the binder has a fourth mass percentage, and the additive has a fifth mass percentage; the second mass percentage includes 0.5% to 35%, the third mass percentage includes 53% to 96%, the fourth mass percentage includes 1% to 3%, and the fifth mass percentage includes 0.05% to 0.5%. The sodium ion positive electrode material, porous carbon, binder and additive are prepared according to the above mass percentages, and the obtained sodium ion positive electrode sheet has good charge and discharge performance and service life.

[0042] The embodiment of the present invention also provides a method for preparing a sodium ion positive electrode sheet. Figure 1 Schematic diagram of a process for preparing a sodium ion positive electrode sheet provided by an embodiment of the present invention. Figure 1 As shown, the method for preparing the sodium ion positive electrode sheet specifically includes the following steps:

[0043] S110, uniformly mixing the binder, the auxiliary agent and the organic solvent to obtain a binder slurry.

[0044] Exemplarily, the organic solvent may include N-methylpyrrolidone, which is not limited herein. The binder and the auxiliary agent are fully mixed with the organic solvent in a certain mass ratio to form a uniform binder slurry.

[0045] S120, uniformly mixing the conductive agent, porous carbon and binder slurry to obtain conductive agent slurry.

[0046] Specifically, the conductive agent, porous carbon and a pre-prepared binder slurry are slowly and evenly mixed in a certain mass ratio to obtain a uniform conductive agent slurry.

[0047] S130, uniformly mixing the capacity compensating agent, the sodium ion positive electrode material and the conductive agent slurry to obtain the sodium ion positive electrode slurry.

[0048] Specifically, the capacity compensating agent, the sodium ion positive electrode material and the pre-prepared conductive agent slurry are slowly and evenly mixed to obtain a uniform sodium ion positive electrode slurry.

[0049] S140, coating the sodium ion positive electrode slurry on the surface of the current collector, and drying, rolling and sheeting the current collector coated with the sodium ion positive electrode slurry to obtain a sodium ion positive electrode sheet; wherein the capacity compensating agent includes a positive electrode lithium replenishing agent having a first mass percentage, and the positive electrode lithium replenishing agent is used to reduce the potential of the negative electrode sheet containing hard carbon and compensate for the irreversible capacity of the negative electrode sheet; the index requirements of the positive electrode lithium replenishing agent are: specific capacity ≥420mAh / g, first coulomb efficiency ≤40%; the index requirements of the porous carbon are: the atomic percentage of carbon atoms ≥92%, the Raman peak intensity ratio ranges from 1.05 to 1.25, and the specific surface area ranges from 1400 to 1700m 2 / g, the micropore specific surface area contribution value is ≥60%, and the particle size range includes 2.0 to 5.0 um; wherein the Raman peak intensity ratio is the intensity ratio of the D peak to the G peak.

[0050] Exemplarily, the current collector may include aluminum foil. The prepared sodium ion positive electrode slurry is uniformly and layer by layer coated on the surface of the aluminum foil, and after coating, the aluminum foil is fully dried to solidify the coated positive electrode slurry. After drying, the aluminum foil is rolled and sheeted to prepare a sodium ion positive electrode sheet.

[0051] The method for preparing a sodium ion positive electrode sheet provided in an embodiment of the present invention first prepares a binder slurry, uses the binder slurry to prepare a conductive agent slurry, and then uses a positive electrode lithium supplement as a capacity compensator, which is fully mixed with the sodium ion positive electrode material and the conductive agent slurry to prepare a sodium ion positive electrode slurry, and then prepares a sodium ion positive electrode sheet. For a sodium ion battery using hard carbon as a negative electrode sheet material, compared to using a positive electrode sodium supplement as a capacity compensator, the embodiment of the present invention uses a positive electrode lithium supplement instead of a positive electrode sodium supplement, which can reduce the hard carbon potential and broaden the voltage window of the sodium ion battery. On the basis of this, it is beneficial to improve the high power characteristics of the sodium ion positive electrode sheet, compensate for the irreversible capacity of the negative electrode, and can effectively improve the initial coulomb efficiency, energy density and cycle life of the sodium ion battery, and reduce the preparation cost of the sodium ion battery.

[0052] Embodiments of the present invention also provide a sodium ion capacitor and a sodium ion battery. The sodium ion capacitor and the sodium ion battery include the sodium ion positive electrode sheet provided by any of the above embodiments, and have the same beneficial effects as the sodium ion positive electrode sheet. Specifically, for a sodium ion battery using hard carbon as the negative electrode sheet material, a positive electrode lithium supplement is used as a capacity compensator to replace the positive electrode sodium supplement, and the sodium ion positive electrode material, porous carbon, binder and additive are fully mixed to obtain a sodium ion positive electrode sheet. On the basis of reducing the hard carbon potential and broadening the voltage window of the sodium ion battery, it is beneficial to improve the high power characteristics of the sodium ion positive electrode sheet, compensate for the irreversible capacity of the negative electrode, and effectively improve the initial coulomb efficiency, energy density and cycle life of the sodium ion battery, thereby reducing the preparation cost of the sodium ion battery.

[0053] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A sodium ion positive electrode sheet, characterized in that: include: Capacity compensator, porous carbon, sodium ion positive electrode material, conductive agent, binder and additive; The capacity compensating agent comprises a positive electrode lithium replenishing agent having a first mass percentage, and the positive electrode lithium replenishing agent is used to reduce the potential of the negative electrode sheet containing hard carbon and compensate for the irreversible capacity of the negative electrode sheet; the index requirements of the positive electrode lithium replenishing agent are: specific capacity ≥420mAh / g, first coulombic efficiency ≤40%; The porous carbon has the following index requirements: the atomic percentage of carbon atoms is ≥ 92%, the Raman peak intensity ratio ranges from 1.05 to 1.25, and the specific surface area ranges from 1400 to 1700 m 2 / g, the micropore specific surface area contribution value is ≥60%, and the particle size range includes 2.0-5.0um; wherein the Raman peak intensity ratio is the intensity ratio of the D peak to the G peak.

2. The sodium ion positive electrode sheet according to claim 1, characterized in that: The first mass percentage includes 1% to 9%.

3. The sodium ion positive electrode sheet according to claim 1, characterized in that: The positive electrode lithium supplement includes a lithium-rich manganese-based material, a lithium-rich nickel-based material and / or a lithium-rich iron-based material.

4. The sodium ion positive electrode sheet according to claim 1, characterized in that: The sodium ion positive electrode material includes at least one of sodium vanadium phosphate, sodium iron phosphate, sodium iron pyrophosphate, sodium nickel cobalt manganate, sodium nickel iron manganate and Prussian blue.

5. The sodium ion positive electrode sheet according to claim 1, characterized in that: The porous carbon includes at least one of activated carbon, carbon nanotubes, graphene, carbon nanocages and onion carbon.

6. The sodium ion positive electrode sheet according to claim 1, characterized in that: The binder includes polyvinylidene fluoride and / or polyacrylic acid resin, and the auxiliary agent includes at least one of polyvinyl pyrrolidone, polycarbonate, lithium aluminum titanium phosphate and lithium lanthanum zirconate.

7. The sodium ion positive electrode sheet according to claim 1, characterized in that: The porous carbon has a second mass percentage, the sodium ion positive electrode material has a third mass percentage, the binder has a fourth mass percentage, and the auxiliary agent has a fifth mass percentage; The second mass percentage includes 0.5% to 35%, the third mass percentage includes 53% to 96%, the fourth mass percentage includes 1% to 3%, and the fifth mass percentage includes 0.05% to 0.5%.

8. A method for preparing a sodium ion positive electrode sheet, characterized in that: include: uniformly mixing the binder, the additive and the organic solvent to obtain a binder slurry; uniformly mixing the conductive agent, the porous carbon and the binder slurry to obtain a conductive agent slurry; The capacity compensating agent, the sodium ion positive electrode material and the conductive agent slurry are uniformly mixed to obtain a sodium ion positive electrode slurry; The sodium ion positive electrode slurry is applied to the surface of the current collector, and the current collector coated with the sodium ion positive electrode slurry is dried, rolled and sheeted to obtain a sodium ion positive electrode sheet; The capacity compensating agent comprises a positive electrode lithium replenishing agent having a first mass percentage, and the positive electrode lithium replenishing agent is used to reduce the potential of the negative electrode sheet containing hard carbon and compensate for the irreversible capacity of the negative electrode sheet; the index requirements of the positive electrode lithium replenishing agent are: specific capacity ≥420mAh / g, first coulombic efficiency ≤40%; The porous carbon has the following index requirements: the atomic percentage of carbon atoms is ≥ 92%, the Raman peak intensity ratio ranges from 1.05 to 1.25, and the specific surface area ranges from 1400 to 1700 m 2 / g, the micropore specific surface area contribution value is ≥60%, and the particle size range includes 2.0-5.0um; wherein the Raman peak intensity ratio is the intensity ratio of the D peak to the G peak.

9. A sodium ion capacitor, characterized in that: It comprises a sodium ion positive electrode sheet as described in any one of claims 1 to 7.

10. A sodium ion battery, characterized in that: It comprises a sodium ion positive electrode sheet as described in any one of claims 1 to 7.

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