Lithium supplement material and preparation method thereof, positive electrode sheet and secondary battery

Abstract

A lithium-supplementing material, a preparation method thereof, a positive electrode plate, and a secondary battery. The lithium-supplementing material comprises a core and an oxygen-consuming agent. The core comprises a lithium-rich compound and has a porous structure; the oxygen-consuming agent is contained within the pores of the core. This invention provides pores within the core composed of the lithium-rich compound and then fills the pores with the oxygen-consuming agent. This allows reactive oxygen species or free radicals generated during the initial charging cycle of the lithium battery to combine with hydrogen atoms provided by the oxygen-consuming agent, thereby preventing the release of reactive oxygen species or free radicals. This reduces the generation of oxygen in the lithium-supplementing material and improves the safety and electrochemical performance of the lithium battery.

Description

Technical Field

[0001] The present application relates to the technical field of secondary batteries, and in particular to a lithium supplement material and a preparation method thereof, a positive electrode sheet and a secondary battery. Background Art

[0002] Lithium-ion batteries have many advantages, but during the first charge of lithium-ion batteries, the negative electrode surface is usually accompanied by the formation of a solid electrolyte membrane SEI film, which consumes a lot of Li + , which means that Li released from the cathode material + Part of it is consumed irreversibly, and the reversible specific capacity of the corresponding battery cell is reduced.

[0003] In recent years, lithium-supplementing materials have attracted much attention because they can compensate for the irreversible capacity loss caused by the formation of SEI film during the first week of charging of lithium-ion batteries. They are one of the key technologies to further improve the performance of lithium-ion batteries and have broad market applications and development prospects.

[0004] However, during research and practical applications, it was found that during the first week of charging, the deintercalation and intercalation of lithium ions in lithium-ion materials will lead to the generation of active oxygen or oxygen-containing free radicals inside the lithium-ion battery. The combination of these groups will cause gas to be generated inside the lithium-ion battery, which will not only affect the structural stability of the lithium-ion battery, but also cause harmful side reactions in the electrolyte. At the same time, it will cause flatulence inside the closed battery system, posing a huge safety problem. Summary of the Invention

[0005] The purpose of this application is to provide a lithium supplement material and a preparation method thereof, a positive electrode plate and a secondary battery.

[0006] This application provides the following technical solutions:

[0007] In the first aspect, the present application provides a lithium-supplementing material, comprising a core and an oxygen-consuming agent, wherein the core comprises a lithium-rich compound, and the core is also a porous structure with a plurality of pores; the oxygen-consuming agent is contained in the pores. The present application opens pores in the core composed of the lithium-rich compound, and then fills the oxygen-consuming agent in the pores, so that the active oxygen or free radicals generated during the first cycle of charging of the lithium battery can be combined with the hydrogen atoms provided by the oxygen-consuming agent, thereby avoiding the escape of the active oxygen or free radicals, thereby reducing the generation of oxygen in the lithium-supplementing material and improving the safety and electrochemical performance of the lithium battery. Moreover, compared with the existing lithium-supplementing materials, the lithium-supplementing material provided by the present application has the oxygen-consuming agent filled inside the core, which can have a larger contact area with the core, thereby improving the combination efficiency of hydrogen atoms and active oxygen or free radicals; filling the oxygen-consuming agent can not only reduce the generation of oxygen, but also reduce the entry of external water vapor or other gases by blocking the pores.

[0008] In one possible embodiment, the distribution density of the holes gradually increases from the core of the core to the outer surface. Since the appearance structure of the core is close to a sphere, the core should have a core and an outer surface away from the core. From the core to the outer surface, that is, it can be understood that the distribution density of the holes gradually increases from the core to the outer surface. It can be understood that as the radius of the core increases, the porosity at the corresponding radius also increases. The advantage of the above arrangement is that the porosity of the outer surface of the core is the largest, and more oxygen-consuming agents can be filled. In this way, not only can the active oxygen and free radicals generated at the outer surface be combined, but the core structure can also be supported by the oxygen-consuming agent to avoid structural collapse of the core from the outside to the inside.

[0009] In one possible implementation, the oxygen-consuming agent is an organic and / or inorganic substance.

[0010] In one possible embodiment, the oxygen consuming agent is a small molecule organic compound with a molecular weight of 60 g / mol to 500 g / mol. The molecular weight of the oxygen consuming agent can affect its particle size and preparation difficulty. When the molecular weight of the oxygen consuming agent is below the above range, the particle size of the oxygen consuming agent is too small, making dispersion more difficult, and the degree of agglomeration increases, making it difficult to form a uniform distribution within the core. When the molecular weight of the oxygen consuming agent is above the above range, the particle size of the oxygen consuming agent is too large and difficult to fill into the pores.

[0011] In one possible embodiment, the oxygen consuming agent includes at least one of an ether oxygen consuming agent, a phenol oxygen consuming agent, and an ester oxygen consuming agent. Specifically, the ether oxygen consuming agent includes at least one of butylated hydroxyanisole, dibutyl hydroxyanisole-d20, and 2,6-dimethyl-4-hydroxyanisole; the phenol oxygen consuming agent includes at least one of 2,6-di-tert-butyl-4-methylphenol, tert-butylhydroquinone, 4-butylphenol, and 2-propylphenol; and the ester oxygen consuming agent includes at least one of propyl gallate, epigallocatechin gallate, and lauryl gallate.

[0012] In one possible embodiment, the specific surface area of the core is 0.5 m 2 / g~60m 2 / g. Controlling the specific surface area of the core within the above range can not only provide space for accommodating the oxygen-consuming agent in the core, but also ensure the structural stability of the core. When the specific surface area of the core is less than the above range, it means that the richness of the pores formed in the core is poor (fewer pores), so that the oxygen-consuming agent cannot be filled into the core, and the content of the oxygen-consuming agent contacted by the unit core is small, which cannot play an effective role in binding active oxygen; when the specific surface area of the core is greater than the above range, it means that the richness of the pores formed in the core is good (more pores), and the structural stability of the core is affected, which will lead to the structural collapse of the lithium-supplementing material. At the same time, it will lead to a higher content of oxygen-consuming agent in the lithium-supplementing material per unit gram. Since the oxygen-consuming agent does not contribute lithium ions, the lithium-supplementing performance of the lithium-supplementing material is affected.

[0013] In one possible embodiment, the core has a porosity of 5% to 80%. The porosity of the core refers to the ratio of the volume of pores in the core to the total volume of the core in its natural state. A lower porosity indicates fewer pores, while a higher porosity indicates more pores. Controlling the porosity within this range effectively controls the abundance of pores. For details, please refer to the above embodiments and are not further elaborated here.

[0014] In one possible embodiment, the pores have a pore diameter of 0.4 nm to 300 nm. The cross-sectional shape of the pores may be circular, elliptical, polygonal or other irregular shapes. Therefore, in this embodiment, the diameter of the pores can be considered to be the opening of the pores on the cross section formed after the core body is cut, and the pore diameter is the maximum value at two points of the opening relative to the inner wall. Controlling the pore diameter within the above range can not only ensure that the formed pores have sufficient accommodation space for accommodating oxygen-consuming agents; at the same time, the core body can also have a suitable specific surface area to avoid the specific surface area being too small or too large. When the pore diameter of the pores is smaller than the above range, the pores cannot provide sufficient accommodation space, resulting in a decrease in the content of oxygen-consuming agents in the core body; when the pore diameter of the pores is larger than the above range, the pore size is too large, the structural stability of the core body is easily affected, and the lithium-rich compound per unit volume is less, which is not conducive to the contribution of lithium ions.

[0015] In one possible embodiment, the oxygen-consuming agent accounts for 0.1% to 10% by mass of the lithium-supplementing material. The mass proportion of the oxygen-consuming agent in the lithium-supplementing material has an important influence on the performance of the lithium-ion battery. Only when the ratio of the oxygen-consuming agent to the lithium-rich compound is controlled within an appropriate range can the oxygen-consuming agent have a positive binding effect on the active oxygen generated in the lithium-rich compound, thereby ensuring that the lithium-supplementing material has excellent electrochemical properties. When the mass proportion of the oxygen-consuming agent is high, the content of the lithium-rich compound in the lithium-supplementing material is low, affecting its lithium-supplementing effect as a lithium-supplementing material; when the mass proportion of the oxygen-consuming agent is low, the oxygen-consuming agent cannot provide enough hydrogen atoms to combine with active oxygen or other free radicals, and the content of active oxygen or other free radicals in the lithium-supplementing material cannot be effectively controlled, making it difficult to improve the electrochemical performance of the lithium battery.

[0016] In one possible embodiment, the distribution density of the oxygen-consuming agent on the core is 0.1 g / cm 3 ~50g / cm 3 By controlling the distribution density of the oxygen-consuming agent on the core body within the above range, it is possible to avoid the oxygen-consuming agent being distributed too densely on the core body, reduce the agglomeration of the oxygen-consuming agent in the core body, and reduce the occurrence of the core body not being accommodated in the core body, thereby ensuring that there is enough oxygen-consuming agent to combine with active oxygen or free radicals per unit volume of the core body.

[0017] In one possible implementation manner, the particle size D50 of the core body is 0.5 μm to 15 μm.

[0018] In one possible implementation, the particle size D50 of the lithium supplementing material is 1 μm to 20 μm.

[0019] In one possible embodiment, the lithium-replenishing material further includes a functional encapsulation layer, which is coated on the outer surface of the core, and at least a portion of the oxygen-consuming agent protrudes from the hole and is located in the functional encapsulation layer. Specifically, at least a portion of the oxygen-consuming agent can also be located on the outer surface of the core to form a functional encapsulation layer. The advantage of using an oxygen-consuming agent to form a functional encapsulation layer is that, on the one hand, it can combine with the active oxygen and free radicals generated by the lithium-rich compound; on the other hand, it can also isolate the core from corrosion by water vapor in the air, inhibit the activity of redox, reduce side reactions at the interface, and greatly improve the cycle stability and high-temperature stability of the lithium-replenishing material.

[0020] In a possible implementation manner, the thickness of the functional encapsulation layer is 1 nm to 100 nm.

[0021] In a possible implementation, the residual alkalinity of the lithium-supplementing material is 0% to 5%.

[0022] In a possible implementation, the first-cycle gas production of the lithium-supplementing material is 0 mg / L-5 mg / L.

[0023] In a second aspect, the present application also provides a method for preparing a lithium-supplementing material, comprising: uniformly mixing a first metal source and a pore-forming agent, and obtaining a first metal oxide having a porous structure after sintering and crushing; uniformly mixing the first metal oxide and a second metal source, and obtaining a core body having a porous structure after sintering, wherein the core body includes a lithium-rich compound; and uniformly mixing the core body and an oxygen-consuming agent to obtain the lithium-supplementing material.

[0024] In a third aspect, the present application also provides a positive electrode plate, which includes a current collector and an active material layer arranged on the current collector, wherein the active material layer includes a positive electrode material and the lithium-supplementing material described in any one of the embodiments of the first aspect, or the active material layer includes a positive electrode material and a lithium-supplementing material obtained by the preparation method of the lithium-supplementing material described in any one of the embodiments of the second aspect.

[0025] In a fourth aspect, the present application also provides a secondary battery comprising the positive electrode sheet described in the third aspect, or the secondary battery comprises the lithium-supplementing material described in any one of the embodiments of the first aspect, or the secondary battery comprises the lithium-supplementing material obtained by the preparation method of the lithium-supplementing material described in any one of the embodiments of the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the implementation methods or the description of the prior art. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A schematic cross-sectional view of a lithium-supplementing material in one embodiment;

[0028] Figure 2 is a schematic cross-sectional view of a core body in one embodiment;

[0029] Figure 3 A schematic cross-sectional view of a lithium-supplementing material including a functional encapsulation layer in one embodiment;

[0030] Figure 4 A schematic flow chart of a method for preparing a lithium-supplementing material in one embodiment;

[0031] Figure 5 This is the XRD pattern of the lithium-supplementing material prepared in Example 1. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of 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.

[0033] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be an intermediate component. When a component is referred to as being "connected to" another component, it may be directly connected to the other component or there may be an intermediate component.

[0034] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" as used in this application includes any and all combinations of one or more of the relevant listed items.

[0035] For ease of understanding, the relevant technical terms involved in the embodiments of this application are explained and described below.

[0036] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0037] In the first aspect, this application provides a lithium supplement material, please refer to Figure 1 and Figure 2 , including a core body 10 and an oxygen-consuming agent 20, wherein the core body 10 includes a lithium-rich compound and is also a porous structure having a plurality of pores 10A; the oxygen-consuming agent 20 is accommodated in the pores 10A.

[0038] Specifically, the core of the lithium-supplementing material can be mainly composed of a lithium-rich compound. The lithium-rich compound is the core of the lithium-supplementing material for providing lithium ions, and the chemical formula of the lithium-rich compound is not specifically limited. Optionally, the shape of the core can be spherical or spherical-like structure or other irregular shapes. The lithium-supplementing material with a lithium-rich compound as the core is added to the electrode, so that during the first cycle of charging, it acts as a "sacrificial agent" to release all the lithium ions contained as much as possible at one time to replenish the irreversible lithium ions consumed by the formation of the SEI film at the negative electrode, thereby maintaining the abundance of lithium ions in the battery system and improving the first efficiency and overall electrochemical performance of the battery.

[0039] In one possible embodiment, the chemical formula of the lithium-rich compound is Li 2+xA y O z , wherein A is one or more elements selected from Fe, Ni, Mn, Cu, Zn, Co, Cr, Zr, Ni, Sb, Ti, V, Mo, and Sn, and -0.5≤x≤8, 0<y, 0<z<13. In a specific embodiment, the lithium-rich compound may be Li5FeO4, Li6MnO4, Li6CoO4, Li6ZnO4, Li2NiO2, Li2CuO2, Li2CoO2, Li2MnO2, Li2Ni 0.5 Mn 1.5 It should be noted that some of the above lithium-rich compounds can be used directly as positive electrode materials, such as Li2NiO2, Li2CuO2, Li2CoO2, Li2MnO2, Li2Ni 0.5 Mn 1.5 O4.

[0040] Optionally, the pores in the core body may be interconnected, and the interior of the core body may be connected to the external space through the pores. For example, the core body may be a spherical structure, and its outer surface may be formed with inwardly recessed pores, with the pores extending from the outer surface toward the interior of the core body. It will be understood that the interior of the core body in the above embodiment may be a porous grid, similar to a honeycomb grid, and the specific shape of the pores is not limited.

[0041] Alternatively, the core body may have multiple, independent pores. For example, the core body may be a spherical structure with inwardly recessed pores formed on its outer surface, i.e., the inner walls of the pores are connected to the outer surface of the core body, and the inner walls of two adjacent pores are not connected to each other. Furthermore, the core body may also have pores that are not connected to the outside (i.e., closed pores).

[0042] The oxygen-consuming agent can be an organic and / or inorganic substance, preferably an organic substance. The oxygen-consuming agent is used to combine with free radicals such as active oxygen, peroxide free radicals, alkoxy free radicals, etc. generated by the lithium-rich compound during the lithium replenishment process. Specifically, during the lithium replenishment process, lithium ions in the lithium-rich compound are deintercalated, so negative ions such as active oxygen or free free radicals will be generated in the lithium-rich compound. The release of negative ions or free free radicals will not only affect the structural stability of the core, but also lead to harmful side reactions in the electrolyte. However, in the existing lithium replenishment materials or positive electrode materials, the oxygen-consuming agent is arranged on the outer surface of the material by external coating, which will lead to a low oxygen binding efficiency. Therefore, by filling the porous structure of the core with the oxygen-consuming agent, not only can it be used to generate hydrogen atoms to react with the above-mentioned ions or free radicals to block the oxidation and detachment process; but also, the oxygen-consuming agent located in the core can also provide a supporting effect for the structure of the core.

[0043] Alternatively, the oxygen-consuming agent and the core body can be combined by blending them together, i.e., pre-forming pores in the core body, and then uniformly mixing the oxygen-consuming agent with the core body so that the oxygen-consuming agent can be filled into the pores. Methods for forming pores in the core body include, but are not limited to, etching, template removal, plasma bombardment, and the like.

[0044] This application creates pores within a core composed of a lithium-rich compound and then fills the pores with an oxygen-consuming agent. This allows the reactive oxygen or free radicals generated during the initial charging cycle of the lithium battery to combine with hydrogen atoms provided by the oxygen-consuming agent, thereby preventing the release of the reactive oxygen or free radicals. This reduces the generation of oxygen in the lithium-supplementing material and improves the safety and electrochemical performance of the lithium battery. Furthermore, compared to existing lithium-supplementing materials, the lithium-supplementing material provided by this application has an oxygen-consuming agent filled within the core, which provides a larger contact area with the core and improves the efficiency of combining hydrogen atoms with reactive oxygen or free radicals. Filling the pores with the oxygen-consuming agent not only reduces oxygen generation but also reduces the ingress of external water vapor or other gases by blocking the pores.

[0045] For a possible implementation, please refer to Figure 2 , from the core to the outer surface of the core body 10, the distribution density of the holes 10A gradually increases. Since the appearance structure of the core body 10 is close to a sphere, the core body 10 should have a core and an outer surface away from the core. From the core to the outer surface, that is, it can be understood that in the direction from the inside to the outside of the core body 10, the distribution density of the holes 10A gradually increases. It can be understood that as the radius of the core body 10 increases, the porosity at the corresponding radius also increases. The advantage of the above arrangement is that the porosity of the outer surface of the core body 10 is the largest, and more oxygen-consuming agents 20 can be filled. In this way, not only can it be ensured that the active oxygen and free radicals generated at the outer surface can be combined, but the structure of the core body 10 can also be supported by the oxygen-consuming agent 20 to avoid structural collapse of the core body 10 from the outside to the inside.

[0046] In one possible embodiment, the oxygen consuming agent is an inorganic substance, and the chemical formula of the oxygen consuming agent can be N a O c , where N is a metal element such as Ce, Ti, Mn, Sn, Zr, W, Al, Mo, Fe, Zn, Cu, Co, Ni, and Cr.

[0047] Furthermore, the chemical formula of the oxygen depleting agent satisfies:

[0048] When N is tetravalent and a=1, 0<c<2;

[0049] When N is hexavalent and a=1, 0<c<3;

[0050] When N is trivalent and a=2, 0<c<3;

[0051] When N is positive and monovalent, a=1, 0<c<1;

[0052] When N is positive divalent or trivalent and a=3, 0<c<4.

[0053] In one possible embodiment, when the oxygen-consuming agent is a small molecule organic substance, the molecular weight is 60 g / mol to 500 g / mol. Specifically, the molecular weight of the oxygen-consuming agent can be, but is not limited to, 60 g / mol, 100 g / mol, 150 g / mol, 180 g / mol, 250 g / mol, 300 g / mol, 450 g / mol, and 500 g / mol. It is understandable that the molecular weight of the oxygen-consuming agent can affect its particle size and preparation difficulty. When the molecular weight of the oxygen-consuming agent is less than the above range, the particle size formed by the oxygen-consuming agent is too small, the dispersion difficulty increases, the degree of agglomeration increases, and it is not easy to form a uniform distribution in the core body; when the molecular weight of the oxygen-consuming agent is greater than the above range, the particle size formed by the oxygen-consuming agent is too large and it is not easy to be filled into the pores.

[0054] In one possible implementation, the oxygen-consuming agent includes at least one of an ether oxygen-consuming agent, a phenol oxygen-consuming agent, and an ester oxygen-consuming agent. Specifically, the ether oxygen-consuming agent includes at least one of butylated hydroxyanisole (molecular weight 180.24 g / mol), dibutyl hydroxyanisole-d20 (molecular weight 256.47 g / mol), and 2,6-dimethyl-4-hydroxyanisole (molecular weight 152.2 g / mol); the phenol oxygen-consuming agent includes at least one of 2,6-di-tert-butyl-4-methylphenol (molecular weight 234.38 g / mol), tert-butylhydroquinone (molecular weight 166.22 g / mol), 4-butylphenol (molecular weight 150.22 g / mol), and 2-propylphenol (molecular weight 136.19 g / mol); the ester oxygen-consuming agent includes at least one of propyl gallate (molecular weight 212.2 g / mol), epigallocatechin gallate (molecular weight 458.37 g / mol), and lauryl gallate (molecular weight 338.44 g / mol).

[0055] In one possible embodiment, the specific surface area of the core is 0.5 m 2 / g~60m 2 / g. Specifically, the specific surface area of the core body can be but not limited to 0.5m 2 / g、1m 2 / g, 2m 2 / g、5m 2 / g、10m 2 / g, 20m 2 / g, 40m 2 / g, 60m 2 / g. It can be understood that the specific surface area of the core body is the total area per unit mass of material, including the area of the inner wall of the pores in the core body and the area of the outer surface of the core body. Moreover, the size of the specific surface area can indirectly reflect the richness of the pores formed in the core body. Controlling the specific surface area of the core body within the above range can not only provide space for accommodating the oxygen-consuming agent in the core body, but also ensure the structural stability of the core body. When the specific surface area of the core body is less than the above range, it means that the richness of the pores formed in the core body is poor (fewer pores), so that the oxygen-consuming agent cannot be filled into the core body, and the content of oxygen-consuming agent contacted by the unit core body is less, and it cannot play an effective active oxygen binding role; when the specific surface area of the core body is greater than the above range, it means that the richness of the pores formed in the core body is better (more pores), and the structural stability of the core body is affected, which will lead to the structural collapse of the lithium-supplementing material. At the same time, it will lead to a higher content of oxygen-supplementing agent in the lithium-supplementing material per unit gram weight. Since the oxygen-supplementing agent does not contribute lithium ions, the lithium-supplementing performance of the lithium-supplementing material is affected.

[0056] In one possible embodiment, the porosity of the core is 5% to 80%. Specifically, the porosity of the core can be, but is not limited to, 5%, 7%, 10%, 15%, 20%, 30%, 50%, or 80%. The porosity of the core refers to the percentage of the volume of pores in the core to the total volume of the core in its natural state. A smaller porosity means fewer pores, and vice versa. Controlling the porosity within the above range can effectively control the richness of the pores. For details, please refer to the above embodiment and will not be elaborated here.

[0057] In one possible embodiment, the pore diameter is 0.4nm to 300nm. Specifically, the pore diameter can be, but is not limited to, 0.4nm, 1nm, 3nm, 10nm, 20nm, 50nm, 100nm, 200nm, and 300nm. The cross-sectional shape of the pore can be circular, elliptical, polygonal, or other irregular shapes. Therefore, the diameter of the pore in this embodiment can be considered to be the opening of the pore on the cross section formed after the core body is cut, and the pore diameter is the maximum value at two points relative to the inner wall of the opening. Controlling the pore diameter within the above range can not only ensure that the formed pore has sufficient accommodation space for accommodating the oxygen-consuming agent; at the same time, the core body can also have a suitable specific surface area to avoid the specific surface area being too small or too large. When the pore diameter is smaller than the above range, the pore cannot provide sufficient accommodation space, resulting in a decrease in the oxygen-consuming agent content in the core body; when the pore diameter is larger than the above range, the pore size is too large, the structural stability of the core body is easily affected, and the amount of lithium-rich compounds per unit volume is less, which is not conducive to the contribution of lithium ions.

[0058] In one possible embodiment, the mass proportion of the oxygen-consuming agent in the lithium-supplementing material is 0.1% to 10%. Specifically, the mass proportion of the oxygen-consuming agent in the lithium-supplementing material can be, but is not limited to, 0.1%, 0.2%, 0.5%, 1%, 3%, 5%, 7%, or 10%. The mass proportion of the oxygen-consuming agent in the lithium-supplementing material has an important impact on the performance of lithium-ion batteries. Only when the ratio of the oxygen-consuming agent to the lithium-rich compound is controlled within an appropriate range can the oxygen-consuming agent have a positive binding effect on the active oxygen generated in the lithium-rich compound, thereby ensuring that the lithium-supplementing material has excellent electrochemical performance. When the mass proportion of the oxygen-consuming agent is high, the content of the lithium-rich compound in the lithium-supplementing material is low, affecting its lithium-supplementing effect as a lithium-supplementing material; when the mass proportion of the oxygen-consuming agent is low, the oxygen-consuming agent cannot provide enough hydrogen atoms to combine with active oxygen or other free radicals, and the content of active oxygen or other free radicals in the lithium-supplementing material cannot be effectively controlled, making it difficult to improve the electrochemical performance of the lithium battery.

[0059] In one possible embodiment, the distribution density of the oxygen-consuming agent on the core is 0.1 mg / cm 3 ~50mg / cm 3 Specifically, the distribution density of the oxygen-consuming agent on the core can be, but is not limited to, 0.1 mg / cm 3 , 0.2mg / cm 3 , 0.5mg / cm 3 , 1mg / cm 3 , 2mg / cm 3 , 5mg / cm 3 、10mg / cm 3 , 20mg / cm 3 、30mg / cm 3 、50mg / cm 3 By controlling the distribution density of the oxygen-consuming agent on the core body within the above range, it is possible to avoid the oxygen-consuming agent being distributed too densely on the core body, reduce the agglomeration of the oxygen-consuming agent in the core body, and reduce the occurrence of the oxygen-consuming agent not being accommodated in the core body, thereby ensuring that there is enough oxygen-consuming agent to combine with active oxygen or free radicals per unit volume of the core body.

[0060] In one possible embodiment, the particle size D50 of the core is 0.5 μm to 15 μm. Specifically, the particle size of the core can be, but is not limited to, 0.5 μm, 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 12 μm, 13 μm, or 15 μm. When the particle size of the core is smaller than the above range, the preparation of the core becomes more difficult, and the particles may form severe agglomerations. In addition, a core particle size that is too small is not conducive to the formation of pores, resulting in fewer pores and difficulty in filling with oxygen depleting agents.

[0061] In one possible embodiment, the particle size D50 of the lithium supplementing material is 1 μm to 20 μm. Specifically, the particle size D50 of the lithium supplementing material can be, but is not limited to, 1 μm, 2 μm, 3 μm, 5 μm, 8 μm, 10 μm, 12 μm, 13 μm, 15 μm, or 20 μm.

[0062] In one possible embodiment, the core can be at least one of primary particles and secondary particles. Secondary particles refer to aggregated particles formed by the aggregation of one or more primary particles. By controlling the core particle size and morphology, the core can not only provide a rich supply of lithium ions, but also improve the processability of the lithium supplement material in the preparation of lithium battery slurry. Furthermore, smaller primary particle sizes can also release more lithium ions.

[0063] For a possible implementation, please refer to Figure 3 The lithium replenishing material further includes a functional encapsulation layer 30 , which is coated on the outer surface of the core 10 , and at least a portion of the oxygen consuming agent 20 protrudes from the hole 10A and is located in the functional encapsulation layer 30 .

[0064] Specifically, the material of functional encapsulation layer 30 is not limited and includes, but is not limited to, organic polymers, carbon materials, or ceramic materials. At least a portion of oxygen-consuming agent 20 protrudes from hole 10A and is located within functional encapsulation layer 30. The advantage of using oxygen-consuming agent 20 to form functional encapsulation layer 30 is that, on the one hand, it can bind with the reactive oxygen species and free radicals generated by the lithium-rich compound; on the other hand, it can also isolate the core 10 from corrosion by moisture in the air, inhibiting redox activity and reducing side reactions at the interface, significantly improving the cycling stability and high-temperature stability of the lithium-supplementing material.

[0065] In one possible embodiment, the thickness of the functional encapsulation layer 30 is 1 nm to 100 nm. Specifically, the thickness of the functional encapsulation layer 30 may be, but is not limited to, 1 nm, 2 nm, 3 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 80 nm, or 100 nm. It can be understood that the thickness of the functional encapsulation layer 30 ensures the specific capacity and electronic conductive environment of the lithium supplement material. When the thickness of the functional encapsulation layer 30 is less than the above range, the functional encapsulation layer 30 does not completely cover the core 10, which is not conducive to building a good electronic conductive environment; when the thickness of the functional encapsulation layer 30 is greater than the above range, since the functional encapsulation layer 30 does not contribute lithium ions, the overall gram capacity of the lithium supplement material will be reduced.

[0066] In one possible embodiment, the residual alkalinity of the lithium-supplementing material is 0% to 5%. Specifically, the residual alkalinity of the lithium-supplementing material can be, but is not limited to, 0%, 0.1%, 0.5%, 1%, 1.5%, 2.5%, 4%, and 5%. The residual alkalinity of the lithium-supplementing material is the residual alkali content that can be detected in the prepared lithium-supplementing material. The lithium-supplementing material provided in the present application can have a lower residual alkalinity because the specific surface area on the metal source is increased by pre-pore formation during the preparation of the lithium-supplementing material. When the lithium source is introduced, the lithium source and other metal sources can have more reactive sites, so that the reaction between the lithium source and the metal source is more sufficient, so the amount of remaining lithium is lower. Therefore, it also reflects the structural excellence of the lithium-supplementing material provided in the present application, which cannot be achieved by other lithium-supplementing materials that do not have a pore structure.

[0067] In one possible embodiment, the gas production of the lithium-supplementing material in the first cycle is 0 mL / g to 10 mL / g. Specifically, the gas production of the lithium-supplementing material in the first cycle can be, but is not limited to, 0 mL / g, 0.1 mL / g, 0.5 mL / g, 1 mL / g, 3 mL / g, 5 mL / g, and 10 mL / g.

[0068] In the second aspect, this application also provides a method for preparing lithium supplement materials, please refer to Figure 4 , specifically used for preparing the lithium supplement material in the first aspect. The preparation method comprises the following steps:

[0069] Step S10: uniformly mix the first metal source and the pore-forming agent, and obtain a first metal oxide having a porous structure after sintering and crushing.

[0070] In step S20 , the first metal oxide and the second metal source are uniformly mixed and sintered to obtain a core body having a porous structure, wherein the core body includes a lithium-rich compound.

[0071] Step S30: uniformly mix the core body and the oxygen consuming agent to obtain a lithium supplement material.

[0072] Specifically, the first metal source in step S10 can be source A in the lithium-rich compound of the first aspect, i.e., an oxide of element A, which can be, but is not limited to, at least one of sulfates, carbonates, acetates, oxides, and hydroxides. Alternatively, the first metal source can be a lithium source, which can be, but is not limited to, one or more of lithium oxide, lithium hydroxide, lithium oxalate, lithium sulfate, and lithium carbonate.

[0073] It can be understood that the first metal source is not limited to the type of metal source. The purpose of mixing the first metal source with the pore-forming agent is to introduce the pore-forming agent into the compound. Since the pore-forming agent needs to be removed eventually, the first metal source can be a lithium compound or other metal compounds other than lithium.

[0074] In a possible embodiment, the pore-forming agent may be, but is not limited to, organic substances such as sodium octadecyl sulfate, hexadecyltrimethylammonium bromide, polyvinylpyrrolidone, polyvinylidene fluoride, polytetrafluoroethylene, and glucose.

[0075] In a possible embodiment, the pore-forming agent may also be an inorganic substance, including but not limited to at least one of ammonium chloride, ammonium carbonate, ammonium oxalate, ammonium bicarbonate, and activated carbon.

[0076] In one possible embodiment, the first metal source and the pore-forming agent may be mixed by a wet process. Specifically, the first metal source and the pore-forming agent may be pre-dispersed in an organic solvent, filtered, and then sintered in a mixed atmosphere.

[0077] In a possible implementation manner, the mass ratio of the first metal source, the pore-forming agent, and the solvent may be 1:(0.005-0.15):(1-20).

[0078] In a possible implementation, the mixed atmosphere may be a mixture of an inert gas and at least one of air, carbon monoxide, and carbon dioxide, and the inert gas may be at least one of nitrogen, argon, helium, and neon.

[0079] It can be understood that the principle of pore formation by using a pore-forming agent is to introduce organic matter into the first metal source. After the organic matter is sintered, and because the sintering environment contains gases that can react with the organic matter (such as air or carbon monoxide, etc.), the organic matter can be completely removed, thereby forming holes at the locations where the organic matter originally existed.

[0080] In a possible implementation manner, the inert atmosphere accounts for 90% to 98%, and other gases account for 2% to 10%.

[0081] In a possible implementation, in the above step S10, the sintering temperature in the mixed atmosphere may be 200° C. to 600° C., and the holding time may be 2 h to 10 h.

[0082] In a possible embodiment, in the above step S20, the sintering environment may be an inert atmosphere, the sintering temperature may be 600° C. to 900° C., and the holding time may be 2 hours to 20 hours.

[0083] In one possible embodiment, in step S30, the core and the oxygen consuming agent may be mixed by a wet method. Specifically, the core and the oxygen consuming agent may be pre-dispersed in an organic solvent, filtered, and then placed in an inert atmosphere to evaporate the solvent at low temperature to obtain the composite lithium supplement material.

[0084] In a possible embodiment, the organic solvent mentioned above may be, but is not limited to, at least one of ethanol, methanol, propanol, N-methylpyrrolidone, and acetone.

[0085] In one possible embodiment, the oxygen-consuming agent before mixing can be in the form of a crystalline powder, which has the advantage that the oxygen-consuming agent in this form has high stability.

[0086] In a possible implementation manner, the mixing mass ratio of the core body and the oxygen-consuming agent is 1:(0.005-0.1).

[0087] The present invention first modifies a first metal source with an organic pore-forming agent to create pores, then mixes and sinters it with a second metal source to produce a porous lithium-rich compound core. Finally, a small molecule organic oxygen-consuming agent is introduced into the porous structure of the core using a wet mixing technique. This method is simple; after sintering the metal source to create pores, it can be incorporated into the normal lithium-supplementing material process.

[0088] In a third aspect, the present application further provides a positive electrode plate, comprising a current collector and an active material layer disposed on the current collector, wherein the active material layer comprises a positive electrode material and the lithium-supplementing material of the first aspect, or the active material layer comprises a positive electrode material and a lithium-supplementing material obtained by the preparation method of the lithium-supplementing material of the second aspect. The positive electrode plate provided by the present application, because it contains the aforementioned lithium-supplementing material, plays the aforementioned role during the charge and discharge process. The lithium-supplementing material can provide active lithium ions that compensate for the formation of the SEI film during the initial charge of the battery, thereby effectively maintaining the gram capacity of the positive electrode plate and improving the capacity retention rate of the positive electrode plate.

[0089] In one possible embodiment, the positive electrode sheet includes a positive electrode current collector, which has a positive electrode active layer on it. The positive electrode active layer includes components such as positive electrode material, conductive agent, binder, etc. This application does not specifically limit these materials, and suitable materials can be selected according to actual application requirements. The positive electrode current collector includes but is not limited to any one of copper foil and aluminum foil. The positive electrode active material can be a phosphate positive electrode active material and a ternary positive electrode active material. In a specific embodiment, it includes one or more of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxyphosphate, fluorolithium vanadium phosphate, lithium titanate, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide. The conductive agent includes one or more of graphite, carbon black, acetylene black, graphene, carbon fiber, C60 and carbon nanotubes, and the content of the conductive agent in the positive electrode active layer is 3wt%-5wt%. The types of binders include one or more of polyvinylidene chloride, soluble polytetrafluoroethylene, styrene-butadiene rubber, hydroxypropyl methylcellulose, methylcellulose, carboxymethyl cellulose, polyvinyl alcohol, acrylonitrile copolymer, sodium alginate, chitosan and chitosan derivatives, and the content of the binder in the positive electrode active layer is 2wt% to 4wt%.

[0090] In one possible implementation, the content of the lithium-supplementing material in the positive electrode material can be controlled at 1% to 6% of the mass of the positive electrode active material. This ratio can just compensate for the loss of active lithium during the first charging process of the battery. If the amount of lithium-supplementing material added to the positive electrode sheet is too low, the active lithium lost in the positive electrode material cannot be fully replenished, which is not conducive to improving the energy density and capacity retention rate of the battery. If the amount of lithium-supplementing material added to the positive electrode material is too high, it may cause lithium plating at the negative electrode to become serious and increase costs. In some specific embodiments, the mass percentage of the lithium-supplementing material in the positive electrode material can be 1%, 2%, 4%, 6%, etc.

[0091] Fourthly, the present application also provides a secondary battery comprising the aforementioned positive electrode plate. The aforementioned lithium-supplementing material is added to the positive electrode plate, or the secondary battery comprises the aforementioned lithium-supplementing material, or the secondary battery comprises the lithium-supplementing material prepared by the aforementioned method. Based on the excellent lithium-supplementing performance and chemical stability of the lithium-supplementing materials of the aforementioned embodiments, the secondary battery of the present application embodiments is endowed with excellent electrochemical and safety performance.

[0092] The technical solution of the present invention is described in detail below through specific embodiments.

[0093] Example 1

[0094] This embodiment provides a lithium supplement material and a preparation method thereof. The lithium supplement material includes a core body composed of Li5FeO4 with a porous structure. The pores of the core body contain an oxygen-consuming agent, butylated hydroxyanisole, which has a molecular weight of 180.24 g / mol.

[0095] The preparation method of the lithium supplement material comprises the following steps:

[0096] (1) Iron oxide, sodium lauryl sulfate, and a solvent are uniformly mixed in a mass ratio of 1:0.5:5, and sintered at 450°C for 5 hours in a mixed atmosphere. After the tube furnace cools down, the material is removed and crushed to obtain porous iron oxide. The mixed atmosphere is 98% nitrogen and 2% carbon dioxide.

[0097] (2) Porous iron oxide and lithium hydroxide are uniformly mixed, wherein the molar ratio of the porous iron oxide to the lithium hydroxide is 0.5:5, and sintered at 750° C. for 10 hours under an inert atmosphere to obtain Li5FeO4 with a porous structure.

[0098] (3) 2 g of Li5FeO4 and 0.002 g of small molecule butylated hydroxyanisole were added to an ethanol solvent, mixed evenly, and then the solvent was evaporated at a low temperature of 60°C under a nitrogen inert atmosphere to obtain a composite lithium-rich material.

[0099] After testing, it was found that in the lithium-supplementing material, the oxygen-consuming agent accounted for 0.1% of the mass of the lithium-supplementing material, and the residual alkalinity of the lithium-supplementing material was 0.2%. Figure 5 This is the XRD spectrum of the lithium supplement material prepared in Example 1. It can be seen from the figure that the prepared lithium supplement material contains the characteristic diffraction peak of Li5FeO4, but because the amount of small molecule organic oxygen consuming agent added is relatively small, its characteristic diffraction peak is not seen in the XRD spectrum.

[0100] Example 2

[0101] This embodiment provides a lithium supplement material and a preparation method thereof. The lithium supplement material includes a core body composed of Li5FeO4 with a porous structure. The pores of the core body contain an oxygen-consuming agent 2,6-di-tert-butyl-4-methylphenol. The molecular weight of 2,6-di-tert-butyl-4-methylphenol is 234.38 g / mol.

[0102] The preparation method of the lithium supplement material comprises the following steps:

[0103] (1) Same as (1) in Example 1.

[0104] (2) Same as (2) in Example 1.

[0105] (3) 2 g of Li5FeO4 and 0.1 g of small molecule 2,6-di-tert-butyl-4-methylphenol were added to an ethanol solvent, mixed evenly, and then the solvent was evaporated at a low temperature of 70 ° C under a nitrogen inert atmosphere to obtain a composite lithium-rich material.

[0106] After testing, it was found that in the lithium-supplementing material, the oxygen-consuming agent accounted for 5% by mass of the lithium-supplementing material, and the residual alkalinity of the lithium-supplementing material was 0%.

[0107] Example 3

[0108] This embodiment provides a lithium supplement material and a preparation method thereof. The lithium supplement material comprises a core body composed of Li5FeO4 with a porous structure, and the pores of the core body are filled with TiO 1.4 Inorganic oxygen consuming agent. The preparation method of the lithium supplement material comprises the following steps:

[0109] (1) Same as (1) in Example 2.

[0110] (2) Same as (2) in Example 2.

[0111] (3) Same as (3) in Example 2, except that the oxygen consuming agent is an oxygen vacancy metal oxide TiO 1.4 Inorganic oxygen depleting agents.

[0112] After testing, it was found that in the lithium-supplementing material, the oxygen-consuming agent accounted for 5% by mass of the lithium-supplementing material, and the residual alkalinity of the lithium-supplementing material was 0%.

[0113] Example 4

[0114] This embodiment provides a lithium supplement material and a preparation method thereof. The lithium supplement material includes a core body composed of Li5FeO4 with a porous structure. The pores of the core body contain an oxygen-consuming agent, propyl gallate, and the molecular weight of propyl gallate is 212.2 g / mol.

[0115] The preparation method of the lithium supplement material comprises the following steps:

[0116] (1) Same as (1) in Example 2.

[0117] (2) Same as (2) in Example 2.

[0118] (3) 2 g of Li5FeO4 and 0.14 g of small molecule propyl gallate were added to an ethanol solvent, mixed evenly, and then the solvent was evaporated at a low temperature of 60°C under a nitrogen inert atmosphere to obtain a composite lithium-rich material.

[0119] After testing, it was found that in the lithium-supplementing material, the oxygen-consuming agent accounted for 7% of the mass of the lithium-supplementing material, and the residual alkalinity of the lithium-supplementing material was 0.1%.

[0120] Example 5

[0121] This embodiment provides a lithium supplement material and a preparation method thereof. The lithium supplement material includes a core body composed of Li5FeO4 with a porous structure. The pores of the core body contain an oxygen-consuming agent, propyl gallate, and the molecular weight of propyl gallate is 212.2 g / mol.

[0122] The preparation method of the lithium supplement material comprises the following steps:

[0123] (1) Same as (1) in Example 4.

[0124] (2) Same as (2) in Example 4.

[0125] (3) Same as (3) in Example 4, except that the amount of small molecule propyl gallate is 0.19 g.

[0126] After testing, it was found that in the lithium-supplementing material, the oxygen-consuming agent accounted for 9.5% of the mass of the lithium-supplementing material, and the residual alkalinity of the lithium-supplementing material was 0.2%.

[0127] Comparative Example 1

[0128] This comparative example provides a lithium supplement material and a preparation method thereof. The lithium supplement material Li5FeO4 has a porous structure.

[0129] The preparation method of the lithium supplement material comprises the following steps:

[0130] (1) Same as (1) in Example 1.

[0131] (2) Same as (2) in Example 1.

[0132] Comparative Example 2

[0133] This comparative example provides a lithium supplement material and a preparation method thereof. The lithium supplement material Li5FeO4 does not have a pore structure feature, and has a functional encapsulation layer of an oxygen-consuming agent on its surface.

[0134] The preparation method of the lithium supplement material comprises the following steps:

[0135] (1) Iron oxide and lithium hydroxide are uniformly mixed, wherein the molar ratio of iron oxide to lithium hydroxide is 0.5:5. The mixture is sintered at 750° C. for 10 h under an inert atmosphere to obtain Li5FeO4.

[0136] (2) 2 g of Li5FeO4 and 0.01 g of small molecule butylated hydroxyanisole were added to a propanol solvent, mixed evenly, and then the solvent was evaporated at a low temperature of 80°C under a nitrogen inert atmosphere to obtain a lithium supplement material.

[0137] The lithium supplement materials provided in Examples 1-5 and the lithium supplement materials provided in Comparative Examples 1-2 were assembled into positive electrodes and lithium-ion batteries respectively according to the following methods:

[0138] Positive electrode: A lithium supplement material and lithium iron phosphate were mixed in a mass ratio of 4:96 to obtain a mixture. The mixture was mixed with polyvinylidene fluoride and SP-Li in a mass ratio of 93:3:4 and stirred by ball milling to obtain a positive electrode slurry. The positive electrode slurry was coated on the surface of aluminum foil, vacuum dried at 110°C overnight, and roller pressed to obtain a positive electrode sheet.

[0139] Negative electrode: Graphite, carboxymethyl cellulose (CMC), SBR, and SP were mixed in a mass ratio of 95.8:1.2:2:1 and ball-milled to obtain a negative electrode slurry. The negative electrode slurry was coated on the surface of copper foil and vacuum-dried at 110°C overnight to obtain a negative electrode sheet.

[0140] Electrolyte: Ethylene carbonate and ethyl methyl carbonate were mixed in a volume ratio of 3:7, and LiPF6 was added to form an electrolyte. The concentration of LiPF6 was 1 mol / L.

[0141] Diaphragm: Polypropylene microporous separator;

[0142] Lithium-ion battery assembly: Assemble button-type lithium-ion full batteries in an inert atmosphere glove box in the order of graphite negative electrode sheet - diaphragm - electrolyte - positive electrode sheet.

[0143] The electrochemical performance of each lithium-ion battery assembled in the above lithium-ion battery embodiment was tested as shown in Table 1, and the test conditions were as follows:

[0144] Constant current and constant voltage charging, the first cycle charge and discharge voltage is 2.5-4.3V, the current is 0.1C, and the cut-off current is 0.01C. 300 cycles are performed at a current of 2C and a cut-off current of 0.01C.

[0145] The test results are shown in Table 1 below:

[0146] Table 1

[0147]

[0148] From the test results of Examples 1-5 and Comparative Examples 1-2 in Table 1, it can be seen that the first-cycle gas production of the composite lithium-supplementing material corresponding to the full battery provided by the examples of the present application is significantly lower than the first-cycle gas production of the composite lithium-supplementing material corresponding to the full battery provided by the comparative example. Correspondingly, the first charging capacity of the full battery corresponding to the composite lithium-supplementing material provided by the examples of the present application and the capacity retention rate after 300 cycles at a current density of 2C are significantly higher than the first charging capacity of the full battery corresponding to the composite lithium-supplementing material provided by the comparative example and the capacity retention rate after 300 cycles at a current density of 2C. This indicates that adding an oxygen-consuming agent to the pore structure of the lithium-supplementing material is beneficial to reducing gas production in the battery and improving the electrochemical performance of the battery. From the full-cell electrochemical data corresponding to Examples 2 and 3, it can be seen that when the oxygen-consuming agent content is the same, filling the pore structure of the lithium-supplementing material with an organic small-molecule oxygen-consuming agent is more conducive to reducing the gas production in the battery; from the electrochemical data of Examples 1, 2, 4, and 5, it can be observed that the initial charging capacity of the lithium-supplementing material increases with the increase in the content of the organic small-molecule oxygen-consuming agent, and then gradually decreases, indicating that the content of the small-molecule oxygen-consuming agent is not the more the better, but must be an appropriate amount to effectively reduce the gas production in the battery and improve the electrochemical performance of the battery. In summary, the present application opens holes in a core composed of a lithium-rich compound and then fills the oxygen-consuming agent in the holes, so that the active oxygen or free radicals generated during the first cycle of charging of the lithium battery can combine with the hydrogen atoms provided by the oxygen-consuming agent, thereby avoiding the escape of active oxygen or free radicals, thereby reducing the generation of oxygen in the lithium-supplementing material and improving the safety and electrochemical performance of the lithium battery.

[0149] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", and "outside" are based on the orientation or positional relationship described in the accompanying drawings. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present application.

[0150] The above disclosure is only a preferred embodiment of the present application, and certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present application are still within the scope covered by the present application.

Claims

1. A lithium supplement material, characterized in that: include: A core body, comprising a lithium-rich compound, wherein the core body is a porous structure having a plurality of pores; The oxygen consuming agent is accommodated in the hole.

2. The lithium supplement material according to claim 1, characterized in that The distribution density of the holes gradually increases from the core to the outer surface of the core.

3. The lithium supplement material according to claim 1, characterized in that The oxygen consuming agent is an organic and / or inorganic substance; and / or the chemical formula of the lithium-rich compound is Li 2+x A y O z , wherein A is one or more elements selected from Fe, Ni, Mn, Cu, Zn, Co, Cr, Zr, Ni, Sb, Ti, V, Mo, and Sn, and -0.5≤x≤8, 0<y, 0<z<13.

4. The lithium supplement material according to claim 1, characterized in that The oxygen consuming agent is a small molecule organic substance, and the molecular weight of the oxygen consuming agent is 60 g / mol to 500 g / mol; and / or the oxygen consuming agent includes at least one of an ether oxygen consuming agent, a phenol oxygen consuming agent, and an ester oxygen consuming agent.

5. The lithium supplement material according to claim 1, characterized in that The specific surface area of the core body is 0.5m 2 / g~60m 2 / g; and / or, the porosity of the core is 5% to 80%; and / or, the pore size is 0.4nm to 300nm.

6. The lithium supplement material according to claim 1, characterized in that The oxygen-consuming agent accounts for 0.1 wt% to 10 wt% of the lithium-supplementing material by weight; and / or the distribution density of the oxygen-consuming agent on the core is 0.1 mg / cm 3 ~50mg / cm 3 .

7. The lithium supplement material according to claim 1, characterized in that The lithium supplement material further includes a functional encapsulation layer, which is coated on the outer surface of the core body. At least a portion of the oxygen consuming agent protrudes from the hole and is located in the functional encapsulation layer.

8. The lithium supplement material according to claim 7, characterized in that The particle size D50 of the core body is 0.5 μm to 15 μm; and / or the particle size D50 of the lithium supplementing material is 1 μm to 20 μm; and / or the thickness of the functional encapsulation layer is 1 nm to 100 nm.

9. The lithium supplement material according to claim 1, characterized in that The residual alkalinity of the lithium-supplementing material is 0% to 5%; and / or the first-cycle gas production of the lithium-supplementing material is 0 mL / g to 10 mL / g.

10. A method for preparing a lithium supplement material, characterized in that: include: uniformly mixing a first metal source and a pore-forming agent, and obtaining a first metal oxide having a porous structure after sintering and crushing; uniformly mixing the first metal oxide and the second metal source, and sintering the mixture to obtain a core body having a porous structure, wherein the core body includes a lithium-rich compound; The core body and the oxygen consuming agent are uniformly mixed to obtain the lithium supplement material.

11. A positive electrode plate, characterized in that: The positive electrode sheet includes a current collector and an active material layer disposed on the current collector, wherein the active material layer includes a positive electrode material and the lithium-supplementing material according to any one of claims 1 to 9, or the active material layer includes a positive electrode material and a lithium-supplementing material obtained by the preparation method of the lithium-supplementing material according to claim 10.

12. A secondary battery, characterized in that: The positive electrode sheet according to claim 11 is included, or the secondary battery comprises the lithium supplement material according to any one of claims 1 to 9, or the secondary battery comprises the lithium supplement material obtained by the preparation method of the lithium supplement material according to claim 10.

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