A lithium-supplemented positive electrode sheet, its preparation method and application

Abstract

This invention provides a lithium-replenishing positive electrode sheet, its preparation method, and its application. The active layer of the lithium-replenishing positive electrode sheet includes a lithium-replenishing agent and additives; the additives include ferrous salts and / or aluminosilicates. The presence of additives in the lithium-replenishing positive electrode sheet of this invention can absorb impurity gases generated by the lithium-replenishing agent, chemically react with HF generated during the formation and capacity testing process, and also act as a catalyst, preventing cell bulging, improving battery safety performance, and reducing damage to the SEI film on the positive / negative electrode surfaces. This allows the lithium-replenishing agent in the positive electrode sheet to achieve maximum specific capacity utilization, significantly improving the electrochemical performance of the battery.

Description

Technical Field

[0001] This invention belongs to the field of battery technology and relates to a lithium-added positive electrode sheet, its preparation method and application. Background Technology

[0002] During the first charge and discharge of a lithium-ion battery, the electrolyte will decompose and reduce on the surface of the negative electrode material to form a solid electrolyte interface (SEI film). The formation of the SEI film is an irreversible process, which will lead to problems such as reduced lithium content, reduced coulombic efficiency and poor cycle performance. Therefore, adding lithium ions to the battery can overcome the above problems.

[0003] Lithium replenishment technology is mainly divided into positive electrode replenishment and negative electrode replenishment. Negative electrode replenishment mainly includes lithium foil replenishment and lithium powder replenishment. However, due to the high reactivity of lithium metal, it has high requirements for storage and manufacturing environments, posing significant safety risks and complex processing risks, resulting in high production costs. Compared with the difficult and high-investment negative electrode replenishment, positive electrode replenishment technology has gained widespread attention due to its high safety and simple production process. Typical positive electrode replenishment involves adding a small amount of high-capacity material during the positive electrode slurry preparation process to compensate for the irreversible capacity loss during the first charge and discharge cycle.

[0004] Currently, common cathode lithium replenishment additives mainly include lithium-rich compounds (Li2NiO2, Li5FeO4) and binary lithium compounds (Li3N, Li2O2). For conventional lithium iron phosphate cells, adding lithium replenishment agents can compensate for the lithium source consumed during the initial charge formation of the SEI film, thus improving the battery's capacity, energy density, and cycle performance. However, these conventional lithium replenishment agents readily react with moisture and carbon dioxide in the air, producing large amounts of gases such as O2 and CO2. This phenomenon is particularly pronounced during the formation stage, leading to gas expansion and cell rupture, causing safety issues.

[0005] To address the above issues, existing technologies have optimized and improved lithium-supplemented battery cells in the following ways: (1) Coating the surface of the positive electrode lithium supplement with LiCoO2, Li2MoO3, Mo2N, ZrO2, or activated carbon to stabilize the lithium supplement structure and slow down its reaction with air; (2) Under a certain humidity environment, the positive electrode lithium supplement reacts with water and carbon dioxide to form stable lithium carbonate on the surface of the positive electrode lithium supplement, isolating the reaction between water and the inner lithium supplement; (3) Extending the formation gas extraction time; However, the first and second methods only slow down the reaction between the positive electrode lithium supplement and air, and cannot solve the problem of large-scale gas generation after the positive electrode lithium supplement is delithiated during the formation stage. The third method is not conducive to the production efficiency of the factory, and incomplete gas removal can easily cause brown spots at the interface.

[0006] Based on the above research, there is a need to provide a lithium-replenishing positive electrode sheet. This lithium-replenishing positive electrode sheet can not only compensate for the lithium source consumed in the formation of the SEI film during the first charge, but also solve the problems of battery over-thickness, bulging, and thermal runaway caused by gas generation in the lithium-replenishing system, as well as the problem of SEI film damage during the formation process. Summary of the Invention

[0007] The purpose of this invention is to provide a lithium-replenishing positive electrode sheet, its preparation method and application. The lithium-replenishing positive electrode sheet includes a lithium replenishing agent for lithium replenishment, as well as additives. Therefore, the lithium-replenishing positive electrode sheet can not only replenish lithium, but also avoid the cell bulging phenomenon, reduce safety hazards, eliminate the influence of the lithium replenishing agent on the SEI film during the formation process, and also enable the lithium replenishing agent to achieve the maximum specific capacity.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a lithium-supplemented positive electrode sheet, wherein the active layer of the lithium-supplemented positive electrode sheet includes a lithium-supplementing agent and an additive;

[0010] The additives include ferrous salts and / or aluminosilicates.

[0011] The additives added to the active layer of this invention can solve the problems of unstable lithium replenishment and gas generation, which damages the SEI film during the formation process. Specifically, because the unstable lithium replenishment reacts with moisture in the air to generate oxygen and carbon dioxide, ferrous salts react with oxygen and absorb impurities, while aluminosilicates react with gaseous impurities such as CO2. Therefore, the presence of the additives avoids cell bulging and reduces safety hazards. On the other hand, aluminosilicates can chemically react with HF generated during the formation and capacity testing process, reducing damage to the SEI film on the positive / negative electrode surfaces. Simultaneously, aluminosilicates can also act as a catalyst, maximizing the specific capacity of the lithium replenishment in the positive electrode.

[0012] Preferably, the additive is a ferrous salt and an aluminosilicate.

[0013] The ferrous salt and aluminum silicate salt described in this invention have a synergistic effect. Since they are present at the same time, they can absorb oxygen and carbon dioxide gas generated by the lithium replenishing agent, thereby maximizing the absorption of impurity gas generated by the lithium replenishing agent and avoiding safety hazards caused by thermal runaway.

[0014] Preferably, the chemical formula of the aluminosilicate is M. x O y·Al2O3·SiO2, wherein M includes any one or at least two of Na, K, Mg, Ca or Fe, and the values ​​of x and y are adaptively adjusted according to the type of M, preferably 0 < x < 2.5, for example, it can be 1, 1.5 or 2, and 0 < y ≤ 3, for example, it can be 1, 1.5 or 3, but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0015] Preferably, the mass ratio of the ferrous salt to the aluminosilicate is (1-4):(6-9), for example, it can be 1:6, 2:7, 3:8 or 4:9, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] The aluminosilicates described in this invention are used in excess of ferrous salts. Aluminosilicates not only absorb impurity gases but also react with HF and act as a catalyst. If the amount of aluminosilicates is too small, it cannot effectively perform its function. Conversely, if the amount of aluminosilicates is too large, the amount of ferrous salt will be too small, thus disrupting the synergistic effect between the two. Therefore, with the total amount of additives remaining constant, the mass ratio of the two should be within a reasonable range to achieve the desired synergistic effect and desired results. Otherwise, it will increase the gas production of the battery, reduce its capacity, and decrease its cycle performance.

[0017] Preferably, the active layer further includes an active material, a binder, and a conductive agent.

[0018] Preferably, the content of the additive accounts for 0.02-0.1 wt% of the total mass of the active material, binder and conductive agent, for example, it can be 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt% or 0.1 wt%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0019] The additives described in this invention must be within a reasonable range to achieve their effect. If the additive content is too low, it will not be able to effectively reduce gas production, and the capacity will decrease, resulting in a decline in cycle performance. If the additive content is too high, it will affect the specific capacity of the electrode, thereby reducing the battery performance.

[0020] Preferably, the ferrous salt includes any one or a combination of at least two of ferrous chloride, ferrous sulfate, ferrous carbonate, ferrous bromide or ferrous iodide. Typical but non-limiting combinations include a combination of ferrous chloride and ferrous sulfate, or a combination of ferrous carbonate and ferrous bromide, preferably ferrous chloride.

[0021] The ferrous salt described in this invention is preferably ferrous chloride. Since ferrous chloride does not introduce other types of ions into the positive electrode system, and its addition will not affect the normal performance of the positive electrode, it has a higher compatibility with the lithium iron phosphate system and results in better battery performance.

[0022] Preferably, the aluminosilicate includes any one or a combination of at least two of sodium aluminosilicate, lithium aluminosilicate, potassium aluminosilicate, magnesium aluminosilicate, ferric aluminosilicate, or calcium aluminosilicate. Typical but non-limiting combinations include a combination of sodium aluminosilicate and lithium aluminosilicate, a combination of potassium aluminosilicate and magnesium aluminosilicate, or a combination of ferric aluminosilicate and calcium aluminosilicate, preferably ferric aluminosilicate.

[0023] The aluminosilicate described in this invention is preferably iron aluminosilicate, because it also does not introduce other types of ions into the positive electrode system.

[0024] Preferably, the particle size D50 of the lithium supplement is 4-10 μm, for example, it can be 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0025] If the particle size D50 of the lithium replenishing agent described in this invention is too small, its surface activity will be too strong, which may lead to risks such as strong water absorption, rapid changes in slurry viscosity and large gas production. On the other hand, if the particle size D50 of the positive electrode lithium replenishing agent is too large, its activity will be weak, and its effect on improving the system capacity and cycle performance will be poor.

[0026] Preferably, based on the mass of the active layer, the content of the lithium supplement is 0.2-0.5 wt%, for example, it can be 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, or 0.5 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] Preferably, the lithium replenishing agent comprises lithium-rich compounds and / or binary lithium compounds.

[0028] Preferably, the lithium-rich compound includes Li2NiO2 and / or Li5FeO4.

[0029] Preferably, the binary lithium compound includes Li3N and / or Li2O2.

[0030] Preferably, based on the mass of the active layer, the content of the active material is 90-95 wt%, for example, it can be 90 wt%, 91 wt%, 92 wt%, 93 wt%, 94 wt% or 95 wt%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0031] Preferably, the content of the adhesive is 1-2 wt% based on the mass of the active layer, for example, it can be 1 wt%, 1.2 wt%, 1.4 wt%, 1.5 wt%, 1.7 wt%, 1.9 wt% or 2 wt%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0032] Preferably, based on the mass of the active layer, the content of the conductive agent is 3-4 wt%, for example, it can be 3 wt%, 3.2 wt%, 3.4 wt%, 3.6 wt%, 3.8 wt%, or 4 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] Preferably, the active material includes any one or a combination of at least two of lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, or ternary materials. Typical but non-limiting combinations include a combination of lithium iron phosphate and lithium cobalt oxide, or a combination of lithium manganese oxide and ternary materials.

[0034] Preferably, the adhesive comprises any one or a combination of at least two of polyvinylidene fluoride, styrene-butadiene rubber, or polyvinyl alcohol. Typical but not limited combinations include a combination of polyvinylidene fluoride and styrene-butadiene rubber, or a combination of polyvinyl alcohol and polyvinylidene fluoride.

[0035] Preferably, the conductive agent includes any one or a combination of at least two of conductive carbon black, conductive graphite, conductive carbon nanotubes, or graphene. Typical but non-limiting combinations include a combination of conductive carbon black and conductive graphite, or a combination of conductive carbon nanotubes and graphene.

[0036] In a second aspect, the present invention provides a method for preparing a lithium-added positive electrode sheet as described in the first aspect, the method comprising the following steps:

[0037] The active material, binder, conductive agent, lithium supplementer and additives are mixed according to the formula, and the resulting mixture is made into a positive electrode slurry. After coating, the lithium supplemented positive electrode sheet is obtained.

[0038] The preparation method used in this invention does not involve coating or doping; additives are added directly during the positive electrode homogenization process. Furthermore, no modification such as coating the lithium supplement is performed. Therefore, the preparation method described in this invention is simple, easy to operate, and low in cost, enabling large-scale industrial application.

[0039] Preferably, the coated foil comprises aluminum foil;

[0040] Preferably, the preparation method further includes the steps of drying after coating, cold pressing, and die-cutting into strips.

[0041] Thirdly, the present invention provides a lithium-ion battery, the lithium-ion battery comprising the lithium-added positive electrode sheet as described in the first aspect.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] This invention adds an additive to the lithium-replenishing positive electrode sheet, which can absorb impurity gases generated by the lithium replenishing agent, avoiding cell bulging and improving safety performance. It can also chemically react with HF generated during the formation and capacity testing process, reducing damage to the SEI film on the positive / negative electrode surfaces and improving the electrochemical performance of the battery. At the same time, it also acts as a catalyst, maximizing the specific capacity of the lithium replenishing agent in the positive electrode sheet. Furthermore, the preparation method of the lithium-replenishing positive electrode sheet described in this invention is simple and low-cost. The lithium replenishing agent and additive can be added during the positive electrode homogenization process without the need for modification of the lithium replenishing agent. Therefore, it can be applied on a large scale in industry. Attached Figure Description

[0044] Figure 1 This is an interface diagram of the battery after disassembly, obtained from the lithium-added positive electrode sheet described in Embodiment 1 of the present invention.

[0045] Figure 2 This is an interface diagram of the battery after disassembly made from the lithium-added positive electrode sheet described in Comparative Example 1 of the present invention. Detailed Implementation

[0046] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0047] Example 1

[0048] This embodiment provides a lithium-supplementing positive electrode sheet, which includes an aluminum foil and active layers on both sides of the aluminum foil. The active layers include active materials, conductive agents, binders, lithium-supplementing agents, and additives.

[0049] The additive is ferrous chloride and ferric aluminosilicate (Fe2O3·Al2O3·SiO2), with a mass ratio of ferrous chloride to ferric aluminosilicate of 3:7; the content of the additive accounts for 0.06 wt% of the total mass of the active material, binder and conductive agent.

[0050] Based on the mass of the active layer, the content of the lithium replenishing agent is 0.4 wt%, the lithium replenishing agent is Li2NiO2, and the particle size D50 is 6 μm;

[0051] Based on the mass of the active layer, the content of the active material is 94.5 wt%, the content of the binder is 1.5 wt%, and the content of the conductive agent is 3.5 wt%. The active material is lithium iron phosphate, the binder is polyvinylidene fluoride, and the conductive agent is conductive carbon black.

[0052] The method for preparing the lithium-added positive electrode sheet includes the following steps:

[0053] The active material, binder, conductive agent, lithium supplementer and additives are mixed according to the formula, and N-methylpyrrolidone is added to make the resulting mixture into a positive electrode slurry. The slurry is coated on both sides of an aluminum foil, and after drying, cold pressing and die cutting, the lithium supplementing positive electrode sheet is obtained.

[0054] The interface diagram of the battery after disassembly made from the lithium-added positive electrode sheet is shown below. Figure 1 As shown.

[0055] Example 2

[0056] This embodiment provides a lithium-supplementing positive electrode sheet, which includes an aluminum foil and active layers on both sides of the aluminum foil. The active layers include active materials, conductive agents, binders, lithium-supplementing agents, and additives.

[0057] The additive is ferrous chloride and ferric aluminosilicate, with a mass ratio of ferrous chloride to ferric aluminosilicate of 1:6; the content of the additive accounts for 0.02 wt% of the total mass of the active material, binder and conductive agent.

[0058] Based on the mass of the active layer, the content of the lithium replenishing agent is 0.5 wt%, the lithium replenishing agent is Li3N, and the particle size D50 is 10 μm;

[0059] Based on the mass of the active layer, the content of the active material is 94 wt%, the content of the binder is 2 wt%, and the content of the conductive agent is 3 wt%. The active material is lithium iron phosphate, the binder is styrene-butadiene rubber, and the conductive agent is conductive carbon nanotubes.

[0060] The method for preparing the lithium-added positive electrode sheet includes the following steps:

[0061] The active material, binder, conductive agent, lithium supplementer and additives are mixed according to the formula, and N-methylpyrrolidone is added to make the resulting mixture into a positive electrode slurry. The slurry is coated on both sides of an aluminum foil, and after drying, cold pressing and die cutting, the lithium supplementing positive electrode sheet is obtained.

[0062] Example 3

[0063] This embodiment provides a lithium-supplementing positive electrode sheet, which includes an aluminum foil and active layers on both sides of the aluminum foil. The active layers include active materials, conductive agents, binders, lithium-supplementing agents, and additives.

[0064] The additive is ferrous chloride and ferric aluminosilicate, with a mass ratio of ferrous chloride to ferric aluminosilicate of 4:9; the content of the additive accounts for 0.1 wt% of the total mass of the active material, binder and conductive agent.

[0065] Based on the mass of the active layer, the content of the lithium replenishing agent is 0.2 wt%, the lithium replenishing agent is Li2O2, and the particle size D50 is 4 μm;

[0066] Based on the mass of the active layer, the content of the active material is 93 wt%, the content of the binder is 2 wt%, and the content of the conductive agent is 4 wt%. The active material is lithium manganese oxide, the binder is styrene-butadiene rubber, and the conductive agent is graphene.

[0067] The method for preparing the lithium-added positive electrode sheet includes the following steps:

[0068] The active material, binder, conductive agent, lithium supplementer and additives are mixed according to the formula, and N-methylpyrrolidone is added to make the resulting mixture into a positive electrode slurry. The slurry is coated on both sides of an aluminum foil, and after drying, cold pressing and die cutting, the lithium supplementing positive electrode sheet is obtained.

[0069] Example 4

[0070] This embodiment provides a lithium-replenishing positive electrode sheet, which is the same as that in Example 1 except that ferrous chloride is replaced by ferrous sulfate.

[0071] Example 5

[0072] This embodiment provides a lithium-replenishing positive electrode sheet, which is the same as that in Embodiment 1 except that ferrous chloride is replaced by ferrous carbonate.

[0073] Example 6

[0074] This embodiment provides a lithium-supplemented positive electrode sheet, which is the same as in Example 1 except that iron aluminosilicate is replaced by magnesium aluminosilicate (MgO·Al2O3·SiO2).

[0075] Example 7

[0076] This embodiment provides a lithium-supplemented positive electrode sheet, which is the same as in Example 1 except that iron aluminosilicate is replaced by potassium aluminosilicate (K2O·Al2O3·SiO2).

[0077] Example 8

[0078] This embodiment provides a lithium-supplemented positive electrode sheet, which is the same as that in Embodiment 1 except that the mass ratio of ferrous chloride to ferric aluminosilicate is 3:5.

[0079] Example 9

[0080] This embodiment provides a lithium-supplemented positive electrode sheet, which is the same as that in Embodiment 1 except that the mass ratio of ferrous chloride to ferric aluminosilicate is 3:10.

[0081] Example 10

[0082] This embodiment provides a lithium-supplemented positive electrode sheet, which is the same as in Example 1 except that the content of the additive accounts for 0.01 wt% of the total mass of the active material, binder and conductive agent.

[0083] Example 11

[0084] This embodiment provides a lithium-supplemented positive electrode sheet, which is the same as in Example 1 except that the content of the additive accounts for 0.15 wt% of the total mass of the active material, binder and conductive agent.

[0085] Example 12

[0086] This embodiment provides a lithium-supplemented positive electrode sheet, which is the same as that in Example 1 except that the additive is ferrous chloride and does not include ferric aluminosilicate.

[0087] Example 13

[0088] This embodiment provides a lithium-supplemented positive electrode sheet, which is the same as that in Example 1 except that the additive is ferric aluminosilicate and does not include ferrous chloride.

[0089] Comparative Example 1

[0090] This embodiment provides a lithium-supplemented positive electrode sheet, which is the same as that in Embodiment 1 except that it does not include additives;

[0091] The interface diagram of the battery after disassembly made from the lithium-added positive electrode sheet is shown below. Figure 2 As shown.

[0092] Comparative Example 2

[0093] This embodiment provides a positive electrode sheet, which is the same as that in Example 1 except that it does not include lithium supplementation agent and additives.

[0094] The positive electrode sheet, negative electrode sheet, and PP separator described in the above embodiments and comparative examples are wound into a core and placed in an aluminum shell. Under negative pressure, electrolyte is injected into the cell. After sufficient settling, subsequent processes such as encapsulation, formation, and capacity testing are performed to obtain a lithium-ion battery. The preparation method of the negative electrode sheet includes: graphite material, conductive carbon black, and styrene-butadiene rubber in a mass ratio of 95:2:3 are mixed evenly in a stirring tank, deionized water is added to prepare a negative electrode slurry, which is coated on copper foil, dried, cold-pressed, and die-cut into strips to prepare a negative electrode sheet. The electrolyte includes 1 mol of LiPF6 as a lithium salt and EC / DC / EMC (volume ratio of 1:1:1) as a solvent.

[0095] The lithium-ion batteries prepared above were tested for gas production volume, calibrated capacity, and capacity retention after 100 cycles. The gas production volume test method was as follows: three sets of each embodiment and comparative example of the prepared lithium-ion batteries were tested in parallel. The gas production volume was tested using the water displacement method. The battery tabs were sealed with insulating tape. One set of batteries (1#) was wrapped with insulating tape, and the battery was submerged in water with the same pulling force maintained by hand, ensuring the battery tabs were level with the water surface. After the balance stabilized, the weight was recorded. The other two sets (2# and 3#) were tested using the same method. Parallel experiments were conducted to obtain the exhaust volumes of groups 1#, 2#, and 3#, and the average exhaust volume of the three groups is shown in Table 1. The test conditions for the calibration capacity were: a controlled temperature of 25±2℃, a charge-discharge test at a rate of 0.5C, 10 cycles, and the average discharge capacity of the last 3 cycles was taken as the calibration capacity. The test conditions for the capacity retention rate after 100 cycles were: a controlled temperature of 25±2℃, a charge-discharge test at a rate of 0.5C, 100 cycles, and the capacity retention rate = discharge capacity of the 100th cycle / discharge capacity of the first cycle. The test results are shown in Table 1.

[0096] Table 1

[0097]

[0098]

[0099] The following points can be observed from Table 1:

[0100] (1) The battery made from the lithium-added cathode sheet provided by the present invention has a small drainage volume, indicating that the battery produces little gas, has a high rated capacity, and good cycle performance. The presence of additives can significantly reduce battery gas production and improve the battery's electrochemical performance. As can be seen from Examples 1 and 4-7, the preferred ferrous salt is ferrous chloride, and the preferred aluminosilicate is ferric aluminosilicate, which can be more suitable for the lithium iron phosphate cathode system and play a synergistic role. As can be seen from Examples 1 and 9-12, the content of additives and the mass ratio of ferrous salt and aluminosilicate should be within a reasonable range to further reduce gas production and improve performance. As can be seen from Examples 1 and 13-14, ferrous salt and aluminosilicate play different roles. The combination of the two can solve the problems of gas production and SEI film damage at the same time, thereby minimizing gas production and improving electrochemical performance.

[0101] (2) As can be seen from Example 1 and Comparative Example 1, Comparative Example 1, without the addition of additives, showed a significant increase in gas production, but a decrease in calibrated capacity and cycle performance. Furthermore, from... Figure 1 and Figure 2 The comparison shows that without the addition of additives, the battery produces more gas, resulting in black spots on the interface. However, the present invention can avoid the appearance of black spots by adding additives, thus ensuring the safety performance of the battery. As can be seen from Example 1 and Comparative Example 2, when neither lithium replenishing agent nor additives are added, the performance of the battery further declines.

[0102] In summary, the present invention provides a lithium-replenishing positive electrode sheet, its preparation method and application. The lithium-replenishing positive electrode sheet can not only make up for the lithium source consumed in the formation of the SEI film during the first charge, but also solve the problems of battery over-thickness, bulging and thermal runaway caused by gas generation in the lithium-replenishing system, as well as the problem of SEI film being damaged during the formation process.

[0103] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A lithium supplemented cathode electrode web, characterized by, The active layer of the lithium-supplemented positive electrode includes a lithium-supplementing agent and additives; The lithium replenishing agent is any one of Li2NiO2, Li5FeO4 or Li2O2; The additives are ferrous salts and aluminosilicates; The mass ratio of the ferrous salt to the aluminosilicate is (1-4):(6-9); The active layer also includes active materials, binders, and conductive agents; The additive content accounts for 0.02-0.1 wt% of the total mass of the active material, binder, and conductive agent.

2. The lithium supplemented cathode electrode web of claim 1, wherein, The ferrous salt includes any one or a combination of at least two of ferrous chloride, ferrous sulfate, ferrous carbonate, ferrous bromide, or ferrous iodide.

3. The lithium supplemented cathode electrode web of claim 1, wherein, The aluminosilicate includes any one or a combination of at least two of sodium aluminosilicate, lithium aluminosilicate, potassium aluminosilicate, magnesium aluminosilicate, iron aluminosilicate, or calcium aluminosilicate.

4. The lithium supplemented cathode electrode web of claim 1, wherein, The particle size D50 of the lithium supplement is 4-10 μm.

5. The lithium supplemented cathode electrode web of claim 1, wherein, Based on the mass of the active layer, the content of the lithium supplement is 0.2-0.5 wt%.

6. The lithium-added positive electrode sheet according to claim 1, characterized in that, Based on the mass of the active layer, the content of the active material is 90-95 wt%.

7. The lithium supplemented cathode electrode web of claim 1, wherein, The content of the adhesive is 1-2 wt%, depending on the mass of the active layer.

8. The lithium supplemented cathode electrode web of claim 1, wherein, Based on the mass of the active layer, the content of the conductive agent is 3-4 wt%.

9. The lithium supplemented cathode electrode web of claim 1, wherein, The active material includes any one or a combination of at least two of lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, or ternary materials.

10. The lithium supplemented cathode electrode web of claim 1, wherein, The adhesive includes any one or a combination of at least two of polyvinylidene fluoride, styrene-butadiene rubber, or polyvinyl alcohol.

11. The lithium supplemented cathode electrode web of claim 1, wherein, The conductive agent includes any one or a combination of at least two of conductive carbon black, conductive graphite, conductive carbon nanotubes, or graphene.

12. A method of making the lithium supplemented cathode web of any one of claims 1-11, wherein, The preparation method includes the following steps: The active material, binder, conductive agent, lithium supplementer and additives are mixed according to the formula, and the resulting mixture is made into a positive electrode slurry. After coating, the lithium supplemented positive electrode sheet is obtained.

13. The method of claim 12, wherein, The coated foil includes aluminum foil.

14. The preparation method according to claim 12, characterized in that, The preparation method also includes the steps of drying after coating, cold pressing, and die-cutting into strips.

15. A lithium-ion battery, characterized in that, The lithium-ion battery includes a lithium-replenishing positive electrode as described in any one of claims 1-11.

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