CN116598491A - Lithium supplementing material, preparation method thereof, positive plate and secondary battery - Google Patents

Lithium supplementing material, preparation method thereof, positive plate and secondary battery Download PDF

Info

Publication number
CN116598491A
CN116598491A CN202310151833.7A CN202310151833A CN116598491A CN 116598491 A CN116598491 A CN 116598491A CN 202310151833 A CN202310151833 A CN 202310151833A CN 116598491 A CN116598491 A CN 116598491A
Authority
CN
China
Prior art keywords
lithium
core
rich material
supplementing
rich
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310151833.7A
Other languages
Chinese (zh)
Inventor
张莉
陈心怡
裴现一男
谭旗清
万远鑫
孔令涌
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Foshan Defang Chuangjie New Energy Technology Co ltd
Qujing Defang Chuangjie New Energy Technology Co ltd
Shenzhen Dynanonic Innovazone New Energy Technology Co Ltd
Original Assignee
Foshan Defang Chuangjie New Energy Technology Co ltd
Qujing Defang Chuangjie New Energy Technology Co ltd
Shenzhen Dynanonic Innovazone New Energy Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Foshan Defang Chuangjie New Energy Technology Co ltd, Qujing Defang Chuangjie New Energy Technology Co ltd, Shenzhen Dynanonic Innovazone New Energy Technology Co Ltd filed Critical Foshan Defang Chuangjie New Energy Technology Co ltd
Priority to CN202310151833.7A priority Critical patent/CN116598491A/en
Publication of CN116598491A publication Critical patent/CN116598491A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/626—Metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The lithium supplementing material comprises a lithium-rich material core, and a first element and a second element which are doped in the lithium-rich material core, wherein the first element is a metal main group element, and the second element is a metalloid element. The electron structure and the space configuration of the active site of the inner core of the lithium-rich material can be regulated and controlled by co-doping of metal elements and metalloid elements, so that particles are thinned, the diffusion speed of lithium ions is improved, and the reversible capacity of the material is improved.

Description

Lithium supplementing material, preparation method thereof, positive plate and secondary battery
Technical Field
The application relates to the technical field of secondary batteries, in particular to a lithium supplementing material and a preparation method thereof, a positive plate and a secondary battery.
Background
With the development of new energy automobiles, the energy density requirements of lithium ion batteries are increasingly high. However, the lithium battery can generate an SEI film in the first charging process, consumes a large amount of lithium ions, so that the capacity of the lithium ions is greatly reduced, and the lithium ions extracted from the negative electrode are far smaller than the lithium ions extracted from the positive electrode during charging in the first discharging process, so that the coulomb efficiency is reduced, and the cycle life and the energy density of the lithium battery are directly influenced.
In order to solve this problem, a positive electrode lithium supplementing method is generally used to eliminate the loss of the irreversible capacity, i.e. a lithium supplementing material is added into the positive electrode material, so as to improve the energy density and other electrical properties of the battery. However, the conventional lithium supplementing materials have the problems of poor structural stability and easiness in side reaction with electrolyte. How to improve the structural stability of the lithium supplementing material and reduce side reactions becomes a key issue.
Disclosure of Invention
The application aims to provide a lithium supplementing material, a preparation method thereof, a positive plate and a secondary battery.
The application provides the following technical scheme:
in a first aspect, the application provides a lithium supplementing material, which comprises a lithium-rich material core, and a first element and a second element doped in the lithium-rich material core, wherein the first element is a metal main group element, and the second element is a metalloid element. Specifically, the lithium-rich material core may be mainly composed of a lithium-rich material, and the chemical formula of the lithium-rich material is not particularly limited. The lithium-rich material core may be spherical or spheroid in structure. Both the first element and the second element may be doped in the form of covalent bonds in the lithium-rich material core. The first element may be distributed in the lithium-rich material core according to a first preset profile; for example, the content of the first element may be in a progressively increasing distribution from the core to the outer surface in the core of the lithium-rich material. And the specific increasing trend can be irregular increase or gradient increase. The electron structure and the space configuration of the active site of the inner core of the lithium-rich material can be regulated and controlled by co-doping of metal elements and metalloid elements, so that particles are thinned, the diffusion speed of lithium ions is improved, and the reversible capacity of the material is improved. Meanwhile, the selected second element has the characteristic similar to the metal element and has excellent conductive performance, so that the first element and the second element have a synergistic effect, and the conductivity of the material can be greatly improved. The first element of the metal system is doped in the lithium-rich material core, so that the metal cations formed by the first element are beneficial to stabilizing the lattice structure of the lithium-rich material core; in addition, the first elements are designed to be distributed according to the first preset, so that the distribution condition of the first elements in the lithium-rich material inner core is controlled, when more first elements exist on the outer surface of the lithium-rich material inner core, the metal cations can firmly stabilize the lattice structure of the outermost layer, side reactions at the interface of the lithium-rich material inner core, which is contacted with electrolyte, are avoided, the inner surface is prevented from structural collapse, and the structural stability of the lithium-supplementing material is improved; meanwhile, as the side reaction between the lithium-rich material core and the electrolyte is reduced, the capacity attenuation problem of the lithium-supplementing material can be effectively relieved, and the cycle performance of the lithium-supplementing material is improved.
In one possible embodiment, the content of the second element may be in a gradually increasing distribution form from the core to the outer surface in the core of the lithium-rich material; but may also be in a progressively decreasing distribution; or the second preset distribution may be an irregular distribution of the second element in the lithium-rich material core.
Possible implementation methodWherein the chemical formula of the lithium-rich material inner core is Li x M y O z Wherein x is more than or equal to 2 and less than or equal to 6, y is more than or equal to 1 and less than or equal to 5, z is more than or equal to 2 and less than or equal to 8, M is selected from at least one element in V, mn, fe, co, ni, cu, zr, the first element comprises at least one element in Al, ga, in, tl, sn, bi, and the second element comprises at least one element in B, si, ge, as, sb, te. Specifically, the elements have larger atomic radius, and by doping the elements into the lithium-rich material core, the characteristic of larger atomic radius can be utilized to improve the stability of crystal lattices, thereby improving the structural stability of the lithium-supplementing material.
In a possible embodiment, the content of the first element increases gradually from the core of the lithium-rich material core to the outer surface of the lithium-rich material core. Specifically, the content of the first element may show a regular gradient increase or an irregular non-gradient increase from the core of the lithium-rich material core to the outer surface of the lithium-rich material core. For example, the mass fraction of the first element at 3nm from the core may be 0.3%, the mass fraction of the first element at 5nm from the core may be 0.5% or 0.6%, and the mass fraction of the first element at 7nm from the core may be 0.7% or 0.8%. The content of the first element is gradually increased from the core of the lithium-rich material core to the outer surface of the lithium-rich material core, so that the crystal lattice structure of the outermost layer is stabilized, the interface between the lithium-rich material core and the electrolyte is more stable, and side reactions are reduced. Moreover, the regular gradient increase is presented, so that the structure of the inner core of the lithium-rich material is more regular, and the stability is higher; and irregular non-gradient increase is presented, which is beneficial to simplifying the preparation process and improving the preparation efficiency.
In a possible embodiment, the content of the second element increases gradually from the core of the lithium-rich material core to the outer surface of the lithium-rich material core. Specifically, the content of the second element may be increased in a regular gradient from the core of the lithium-rich material core to the outer surface of the lithium-rich material core, or may be increased in an irregular non-gradient. For example, the mass fraction of the second element at 3nm from the core may be 0.5%, the mass fraction of the second element at 5nm from the core may be 0.6% or 0.7%, and the mass fraction of the second element at 7nm from the core may be 0.8% or 0.9%. It can be appreciated that as the radius of the inner core of the lithium-rich material increases gradually from the core to the outer surface, the outer surface can have more sites for accommodating metal cations and nonmetal cations, and the nonmetal cations and the metal cations can be matched by increasing the second element and the first element, so that the structural stability of the lithium-rich material is further improved.
In one possible embodiment, the mass fraction of the first element in the lithium-rich material core is 0.1% -10%; the mass fraction of the second element in the lithium-rich material core is 0.5% -5%. It is understood that the mass fraction of the first element and the second element is the doping content of the first element and the second element in the lithium-rich material core. When the mass fraction of the first element or the second element is smaller than the above range, that is, the doping content of the first element or the second element is lower, the first element or the second element cannot play a good structural support stabilizing role; when the mass fraction of the first element or the second element is greater than the above range, the doping content of the first element or the second element is higher, resulting in a lower content of lithium ions, which may decrease the lithium supplementing ability of the lithium supplementing material.
In one possible embodiment, the lithium-rich material core comprises a plurality of single crystal particles having a particle size in the range of 2nm to 20nm.
In one possible embodiment, the D50 particle size of the lithium supplementing material is in the range of 5nm to 10 μm. It can be understood that the lithium supplementing material with small particle size has larger active specific surface area, which is favorable for lithium ion intercalation and deintercalation. When the particle size of the lithium supplementing material is smaller than the above range, the particles form relatively serious agglomeration; when the particle diameter of the lithium-supplementing material is larger than the above range, the specific surface area of the lithium-supplementing material is reduced, and the intercalation and deintercalation efficiency of lithium ions is lowered, thereby resulting in poor lithium supplementing effect of the lithium-supplementing material.
In a possible implementation manner, the lithium supplementing material further comprises an encapsulation layer, the encapsulation layer is coated on the outer surface of the lithium-rich material core, and the thickness of the encapsulation layer is 2 nm-100 nm. It will be appreciated that the thickness of the encapsulation layer ensures both the specific capacity of the lithium-compensating material and the electronically conductive environment. When the thickness of the packaging layer is smaller than the range, the packaging layer does not completely cover the lithium-rich material inner core, so that a good electronic conductive environment is not constructed; when the thickness of the encapsulation layer is greater than the above range, since the encapsulation layer does not contribute lithium ions, the gram capacity of the entire lithium supplementing material is reduced.
In a second aspect, the present application also provides a method for preparing a lithium supplementing material, including: adding a main body solution, a first solution and a precipitant into a substrate solution, and reacting to obtain a first precursor, wherein the first solution comprises a first element which is a metal main group element; and mixing the first precursor, a lithium source and a second precursor, and then performing high-temperature reaction to obtain the lithium-rich material core, wherein the second precursor comprises a second element, and the second element is a metalloid element.
In a possible embodiment, the first solution is an aqueous solution of metal ions including the first element; the second precursor is a metalloid oxide comprising the second element; the precipitant is at least one of hydroxide, carbonate or oxalate; the substrate solution is at least one of ammonia water, citric acid or ethylenediamine.
In a third aspect, the present application also provides a positive electrode material comprising a positive electrode active material and the lithium supplementing material according to any one of the first aspects.
In a fourth aspect, the present application also provides a positive electrode sheet, including the positive electrode material according to the third aspect.
In a fifth aspect, the present application also provides a secondary battery, including the positive electrode sheet according to the fourth aspect.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the application, and that other drawings can be obtained from them without inventive effort for a person skilled in the art.
FIG. 1 is a schematic cross-sectional view of a lithium-compensating material in one embodiment;
FIG. 2 is a schematic diagram showing the variation of the first element content in the lithium-supplementing material according to one embodiment;
FIG. 3 is a flow chart of the preparation of a lithium-supplementing material in one embodiment;
FIG. 4A is a scanning electron microscope image of the lithium-rich material core of comparative example 1;
fig. 4B is a scanning electron microscope image of the lithium-rich material core of example 1.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, are intended to fall within the scope of the present application.
It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When a component is considered to be "connected" to another component, it can be directly connected to the other component or intervening components may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
Some embodiments of the present application are described in detail below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.
In a first aspect, referring to fig. 1, the present application provides a lithium supplementing material, which includes a lithium-rich material core 10, and a first element and a second element doped in the lithium-rich material core 10, wherein the first element is a metal main group element, and the second element is a metalloid element.
Specifically, the lithium-rich material core may be mainly composed of a lithium-rich material, and the chemical formula of the lithium-rich material is not particularly limited. The lithium-rich material core may be spherical or spheroid in structure. Both the first element and the second element may be doped in the form of covalent bonds in the lithium-rich material core. The first element may be distributed in the lithium-rich material core according to a first preset profile; for example, the content of the first element may be in a progressively increasing distribution from the core to the outer surface in the core of the lithium-rich material. And the specific increasing trend can be irregular increase or gradient increase. For example, referring to fig. 2, the abscissa indicates the distance H from the core to the outer surface of the lithium-rich material core, and the ordinate indicates the content T of the first element. A is a straight line, so that the content of the first element is in a uniform gradient increasing form along with the change of the distance from the core to the outer surface; b is a curve so that the content of the first element exhibits a non-uniform irregularly increasing pattern as a function of the distance from the core to the outer surface.
The electron structure and the space configuration of the active site of the inner core of the lithium-rich material can be regulated and controlled by co-doping of metal elements and metalloid elements, so that particles are thinned, the diffusion speed of lithium ions is improved, and the reversible capacity of the material is improved. Meanwhile, the selected second element has the characteristic similar to the metal element and has excellent conductive performance, so that the first element and the second element have a synergistic effect, and the conductivity of the material can be greatly improved. The first element of the metal system is doped in the lithium-rich material core, so that the metal cations formed by the first element are beneficial to stabilizing the lattice structure of the lithium-rich material core; in addition, the first elements are designed to be distributed according to the first preset, so that the distribution condition of the first elements in the lithium-rich material inner core is controlled, when more first elements exist on the outer surface of the lithium-rich material inner core, the metal cations can firmly stabilize the lattice structure of the outermost layer, side reactions at the interface of the lithium-rich material inner core, which is contacted with electrolyte, are avoided, the inner surface is prevented from structural collapse, and the structural stability of the lithium-supplementing material is improved; meanwhile, as the side reaction between the lithium-rich material core and the electrolyte is reduced, the capacity attenuation problem of the lithium-supplementing material can be effectively relieved, and the cycle performance of the lithium-supplementing material is improved.
In one possible embodiment, the content of the second element is distributed in the lithium-rich material core according to a second preset. For example, the content of the second element may be in a progressively increasing distribution from the core to the outer surface in the core of the lithium-rich material; but may also be in a progressively decreasing distribution; or the second preset distribution may be an irregular distribution of the second element in the lithium-rich material core. Reference may be made specifically to the content variation of the first element, and no further description is given here.
In one possible embodiment, the lithium-rich material core has the chemical formula Li x M y O z Wherein x is more than or equal to 2 and less than or equal to 6, y is more than or equal to 1 and less than or equal to 5, z is more than or equal to 2 and less than or equal to 8, M is selected from at least one element in V, mn, fe, co, ni, cu, zr, the first element comprises at least one element in Al, ga, in, tl, sn, bi, and the second element comprises at least one element in B, si, ge, as, sb, te. Specifically, the elements have larger atomic radius, and by doping the elements into the lithium-rich material core, the characteristic of larger atomic radius can be utilized to improve the stability of crystal lattices, thereby improving the structural stability of the lithium-supplementing material.
In one possible embodiment, the content of the first element increases gradually from the core of the lithium-rich material core to the outer surface of the lithium-rich material core. Specifically, the content of the first element may exhibit a regular gradient increase, or an irregular non-gradient increase, from the core of the lithium-rich material core to the outer surface of the lithium-rich material core. For example, the mass fraction of the first element at 3nm from the core may be 0.3%, the mass fraction of the first element at 5nm from the core may be 0.5% or 0.6%, and the mass fraction of the first element at 7nm from the core may be 0.7% or 0.8%. The content of the first element is gradually increased from the core of the lithium-rich material core to the outer surface of the lithium-rich material core, so that the crystal lattice structure of the outermost layer is stabilized, the interface between the lithium-rich material core and the electrolyte is more stable, and side reactions are reduced. Moreover, the regular gradient increase is presented, so that the structure of the inner core of the lithium-rich material is more regular, and the stability is higher; and irregular non-gradient increase is presented, which is beneficial to simplifying the preparation process and improving the preparation efficiency.
In one possible embodiment, the second element is present in an increasing amount from the core of the lithium-rich material core to the outer surface of the lithium-rich material core. Specifically, the content of the second element may exhibit a regular gradient increase, or an irregular non-gradient increase, from the core of the lithium-rich material core to the outer surface of the lithium-rich material core. For example, the mass fraction of the second element at 3nm from the core may be 0.5%, the mass fraction of the second element at 5nm from the core may be 0.6% or 0.7%, and the mass fraction of the second element at 7nm from the core may be 0.8% or 0.9%. It can be appreciated that as the radius of the inner core of the lithium-rich material increases gradually from the core to the outer surface, the outer surface can have more sites for accommodating metal cations and nonmetal cations, and the nonmetal cations and the metal cations can be matched by increasing the second element and the first element, so that the structural stability of the lithium-rich material is further improved.
In one possible embodiment, the mass fraction of the first element in the lithium-rich material core is 0.1% -10%; the mass fraction of the second element in the lithium-rich material core is 0.5% -5%. It is understood that the mass fraction of the first element and the second element is the doping content of the first element and the second element in the lithium-rich material core. When the mass fraction of the first element or the second element is smaller than the above range, that is, the doping content of the first element or the second element is lower, the first element or the second element cannot play a good structural support stabilizing role; when the mass fraction of the first element or the second element is greater than the above range, the doping content of the first element or the second element is higher, resulting in a lower content of lithium ions, which may decrease the lithium supplementing ability of the lithium supplementing material.
In one possible embodiment, referring to fig. 1, the lithium-rich material core includes a plurality of single crystal particles 30, and the single crystal particles 30 have a particle size ranging from 2nm to 20nm. Further, the lithium-rich material core may be formed by stacking a plurality of single crystal particles. The grain size range of monocrystalline particles in the existing lithium-rich material is generally 20-50 nm, the monocrystalline particles can be thinned by doping the first element and the second element, the grain size of the monocrystalline particles is obviously reduced, the diffusion speed of lithium ions is improved, and the reversible capacity of the material is further improved.
In one possible embodiment, the D50 particle size of the lithium-rich material core is in the range of 5nm to 10 μm. It can be appreciated that the lithium-rich material core with small particle size has larger active specific surface area, which is beneficial to lithium ion intercalation and deintercalation. When the particle size of the inner core of the lithium-rich material is smaller than the range, the overall size of the lithium-supplementing material is easy to be smaller, and the particles form more serious agglomeration; when the particle diameter of the inner core is larger than the above range, the specific surface area of the inner core of the lithium-rich material is reduced, and the intercalation and deintercalation efficiency of lithium ions is reduced, thereby resulting in poor lithium supplementing effect of the lithium supplementing material.
In a possible embodiment, referring to fig. 1, the lithium supplementing material further includes an encapsulation layer 20, the encapsulation layer 20 is wrapped on the outer surface of the lithium rich material core 10, and the thickness of the encapsulation layer 20 is 2 nm-100 nm. It will be appreciated that the thickness of the encapsulation layer 20 ensures both the specific capacity of the lithium-compensating material and the electronically conductive environment. When the thickness of the encapsulation layer 20 is smaller than the above range, the encapsulation layer 20 does not completely cover the lithium-rich material core 10, which is not beneficial to building a good electron conduction environment; when the thickness of the encapsulation layer 20 is greater than the above range, since the encapsulation layer 20 does not contribute lithium ions, the gram capacity of the entire lithium supplementing material is reduced.
In one possible embodiment, the encapsulation layer may include at least one of an isolation encapsulation layer, an ion conductor encapsulation layer, and an electronic conductor encapsulation layer. The packaging layers can effectively improve the electronic and ionic conductivity of the inner core of the lithium-rich material and improve the release of lithium in the charging process; can also play a certain role in isolating moisture, improve the stability of the lithium supplementing material and realize a stable lithium supplementing effect. In addition, the stability, the dispersion uniformity and the good processing performance of the lithium supplementing material in the electrode active slurry and the active layer can be ensured.
In one possible embodiment, the encapsulation layer is a carbon layer, and the carbon source of the encapsulation layer may be an organic carbon source, including, but not limited to, sugar organics, citric acid, polyvinyl alcohol, phenolic resin, dopamine, polyvinylpyrrolidone, tannic acid, and the like. Preferably, the carbon source is sucrose, glucose, fructose, starch.
In a second aspect, the present application further provides a method for preparing a lithium-supplementing material, please refer to fig. 3, which is specifically used for preparing the lithium-supplementing material in the first aspect. The preparation method comprises the following steps:
step S10, adding a main body solution, a first solution and a precipitant into a substrate solution, and reacting to obtain a first precursor, wherein the first solution comprises a first element which is a metal main group element.
And step S20, mixing the first precursor, the lithium source and the second precursor, and then obtaining the lithium-rich material core through high-temperature reaction, wherein the second precursor comprises a second element, and the second element is a metalloid element.
In a possible embodiment, the first solution is an aqueous solution of metal ions including a first element, which may specifically be an inorganic salt, and the first element includes at least one element of Al, ga, in, tl, sn, bi provided in the above embodiment. Optionally, the concentration of the first element in the first solution increases over time. For example, the first solution may be an aqueous solution of aluminum sulfate and/or an aqueous solution of magnesium sulfate, etc. The concentration of the first solution is changed from 0.001mol/L to 0.2mol/L with time, and the concentration increasing rate of the first solution is 0.001mol/L/h to 0.05mol/L/h. For example, the concentration of the first solution may be 0.001mol/L at the initial stage of the introduction of the first solution, and then the concentration of the first solution may be 0.2mol/L at the termination stage of the introduction of the first solution by controlling the concentration increase of the first solution at a rate of 0.02 mol/L/h. By setting the concentration of the introduced solution to be continuously increased, gradient doping of the first element from the inner core to the surface can be realized.
In one possible implementation manner, the first solution may be provided in advance with two types of first solutions with different concentrations, which may be respectively denoted as a first solution a and a first solution B, where the content of the first element in the first solution a is smaller, and the content of the first element in the first solution B is larger. The concentration of the first solution A may be 0.05mol/L to 0.9mol/L, and the concentration of the first solution B may be 0.99mol/L to 4mol/L. The first solution A is introduced into the substrate solution in advance, and then the first solution B is introduced into the first solution A, so that the concentration of the first solution A can be increased with the change of time. The flow rate of the first solution A can be 0.5 mL/min-1.0 mL/min, and the flow rate of the first solution B can be 1.0 mL/min-1.5 mL/min. Preferably, the concentration of the first solution A may be 0.06mol/L to 0.6mol/L, and the concentration of the first solution B may be 1mol/L to 3mol/L.
In one possible embodiment, the host solution is a precursor for preparing the lithium-rich material core, and may specifically be an inorganic salt, and the host solution and the first solution should be different solutions of inorganic salts. The concentration of the main body solution can be 1-6 mol/L, and the flow rate of the main body solution can be 2-2.5 mL/min. It will be appreciated that the host solution is prepared according to the formula Li x M y O z The precursor of the compound comprises an inorganic salt taking M as a metal ion in a main body solution, wherein M is at least one element selected from V, mn, fe, co, ni, cu, zr.
In one possible embodiment, the precipitating agent is at least one of a hydroxide, a carbonate, or an oxalate. The concentration of the precipitant can be 1mol/L to 10mol/L, and the flow rate of the precipitant can be 0.01mL/min to 1mL/min.
In one possible embodiment, the substrate solution is at least one of ammonia, citric acid, or ethylenediamine. The substrate solution can be used as a complexing agent in the whole solution system for complexing metal ions and preventing metal hydroxide from directly separating out.
In one possible implementation, the specific implementation of step S10 may be that the bulk solution, the first solution and the precipitant may all be introduced into the base solution at a constant flow rateIs a kind of medium. The main body solution and the first solution can be first complexed with the substrate solution to form a complex, then under the action of the precipitant, metal ions in the complex are released to form a precipitate, and the formed precipitate is the first precursor. The first precursor may have the formula [ M ] 1-a K1 a ](OH) b Wherein K1 is the first element in the above embodiment, and 0.001.ltoreq.a.ltoreq.0.1. Preferably, a may be 0.001, 0.02, 0.04, 0.06, 0.08, 0.1. By adopting the method to synthesize the first precursor, the nucleation rate in the crystallization process can be reduced to a certain extent, and the bulk density of the sample can be improved.
In one possible embodiment, the pH of the reaction environment is from 11.0 to 11.5. By controlling the pH value within the above range, the purposes of adjusting the morphology and the particle size distribution of the precursor can be achieved. When the pH value of the reaction environment is lower than the above range, the formed first precursor particles are easy to agglomerate, have different shapes and have large particle size difference; when the pH of the reaction environment is higher than the above range, the first precursor particles formed are more spherical and have too small particle size.
In one possible embodiment, the reaction time is from 10 to 15 hours. When the reaction time is less than the above range, the tap density of the lithium-compensating material is easily made too small due to the too short reaction time; when the reaction time is longer than the above range, since the increase in tap density tends to be gentle, the long-time reaction is liable to cause unnecessary waste.
In one possible embodiment, the second precursor is a non-metal oxide comprising a second element. The second element includes at least one element of B, si, se, P provided in the above embodiment. The lithium source is LiCl, li 2 CO 3 、LiNO 3 、LiOH·H 2 O、Li 2 O, etc.
In a possible implementation manner, step S20 may be specifically implemented by mixing a lithium source, a first precursor and a second precursor according to a certain molar ratio, performing ball milling, and performing a high-temperature solid-phase reaction in an inert atmosphere to obtain a lithium-rich material doped with a first element and a second element in a gradient manner Kernel K1 G -K2-Li x M y O z Wherein K1 is the first element in the above embodiment, K2 is the second element in the above embodiment, and G represents the content gradient.
In one possible embodiment, the lithium source, the first precursor and the second precursor are mixed in a molar ratio of 2 to 6:1: mixing 0.01-0.05, and calcining at high temperature.
In one possible embodiment, the high temperature solid phase reaction condition is that the temperature is kept for 2 to 5 hours in an inert atmosphere at 450 to 550 ℃; then heating, and preserving heat for 10-15 h in an inert atmosphere at 600-800 ℃. Optionally, the heating rate is 2-5 ℃/min.
In one possible embodiment, the method for preparing the lithium supplementing material further includes:
and step S30, ball-milling and mixing the inner core of the lithium-rich material with a carbon source, and sintering in an inert atmosphere to obtain the lithium-supplementing material. Specifically, the lithium supplementing material is in a core-shell structure and comprises a lithium-rich material inner core and an encapsulation layer coated on the outer surface of the lithium-rich material inner core.
In one possible embodiment, the carbon source may be an organic carbon source, and specific reference may be made to the above embodiment, which is not described herein. The mass fraction of the final encapsulation layer may be 0.5wt% to 10wt%.
In one possible embodiment, the sintering condition is that the temperature is kept for 4 to 8 hours in an inert atmosphere at 600 to 700 ℃ and the temperature rising rate is 2 to 5 ℃ per minute.
In a third aspect, the present application also provides a positive electrode material. The positive electrode material includes a positive electrode active material, and the lithium supplementing material in the first aspect or the lithium supplementing material prepared by the preparation method in the second aspect. Thus, the positive electrode material provided by the embodiment of the application has excellent lithium supplementing performance and good processing performance, can improve the quality of the positive electrode active material, and endows the positive electrode plate with electrochemical performance. The positive electrode active material may be a phosphate positive electrode active material or a ternary positive electrode active material, and in specific embodiments, the positive electrode active material includes one or more of lithium cobaltate, lithium manganate, lithium iron phosphate, lithium iron manganese phosphate, lithium vanadium phosphate, lithium vanadyl phosphate, lithium vanadium fluorophosphate, lithium titanate, lithium nickel cobalt manganate, and lithium nickel cobalt aluminate.
In one possible embodiment, the content of the lithium supplementing material in the positive electrode material may be controlled to be 1% -6% of the mass of the positive electrode active material. The ratio can exactly compensate the loss of active lithium in the first charging process of the battery. If the addition amount of the lithium supplementing material in the positive electrode plate is too low, the lost active lithium in the positive electrode material cannot be fully supplemented, and the energy density, the capacity retention rate and the like of the battery are not improved. If the addition amount of the lithium supplementing material in the positive electrode material is too high, lithium may be severely separated from the negative electrode, and the cost may be increased. In some embodiments, the mass percentage of the lithium supplementing material in the positive electrode material may be 1%, 2%, 4%, 6%, etc.
In a fourth aspect, the present application further provides a positive electrode sheet, where the positive electrode sheet includes the lithium supplementing material in the first aspect, or the lithium supplementing material prepared by the preparation method in the second aspect, or the positive electrode material in the third aspect. The positive plate provided by the application contains the lithium supplementing material, and the lithium supplementing material can provide active lithium ions which are consumed by the formation of the SEI film when the battery is charged for the first time, so that the gram capacity of the positive plate is effectively maintained, and the capacity retention rate of the positive plate is improved; meanwhile, the lithium supplementing material can release lithium polysulfide to eliminate lithium precipitation, so that the performance of the positive plate can be maintained, and the service life of the positive plate can be prolonged.
In a possible embodiment, the positive plate further comprises a positive current collector, the positive current collector is provided with a positive active layer, the positive active layer comprises positive materials, a conductive agent, a binder and the like, the materials are not particularly limited, and suitable materials can be selected according to practical application requirements. The positive electrode current collector includes, but is not limited to, any one of copper foil and aluminum foil. The conductive agent comprises one or more of graphite, carbon black, acetylene black, graphene, carbon fiber, C60 and carbon nano tube, and the content of the conductive agent in the positive electrode active layer is 3-5 wt%. The binder comprises one or more of polyvinylidene chloride, soluble polytetrafluoroethylene, styrene-butadiene rubber, hydroxypropyl methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, acrylonitrile copolymer, sodium alginate, chitosan and chitosan derivative, and the content of the binder in the positive electrode active layer is 2-4wt%.
In a fifth aspect, the present application further provides a secondary battery, where the secondary battery includes the positive electrode sheet. The positive plate is added with the lithium supplementing material, so that active lithium ions consumed by the formation of an SEI film when the battery is charged for the first time can be effectively compensated, gram capacity of the positive plate is effectively maintained, and capacity retention rate of the positive plate is improved. Meanwhile, the shape of the secondary battery can be maintained, the service life of the secondary battery is prolonged, and the charging capacity of the secondary battery can be increased due to elimination of lithium precipitation, so that the natural possibility of the secondary battery is reduced.
The technical scheme of the application is described in detail by specific examples.
Example 1
The embodiment provides a lithium supplementing material and a preparation method thereof, wherein the lithium supplementing material comprises a lithium-rich material inner core Li 2 NiO 2 The lithium-rich material is coated with an inner core Li 2 NiO 2 The carbon layer (packaging layer) on the outer surface, the inner core of the lithium-rich material is doped with Al element and B element, and the content of Al gradually increases from the core of the inner core of the lithium-rich material to the surface.
The preparation method of the lithium supplementing material comprises the following steps:
(1) 2mol/L NiSO 4 At a flow rate of 2mL/min, 0.1mol/L Al 2 (SO 4 ) 3 Is pumped into the base solution NH at a flow rate of 0.5mL/min and 4mol/L NaOH 4 In OH; at the same time, 1mol/L of Al is pumped into the first solution A at a flow rate of 1mL/min 2 (SO 4 ) 3 The pumping time of the first solution is controlled so that the Al doping amount is 0.1 percent of the mass fraction of the lithium-rich material. Controlling the pH=11.3 of the reaction environment, stirring for 12 hours at the temperature of 50 ℃ at 800rpm to obtain an Al element gradient doped precursor [ Ni ] 0.0.99 Al 0.001 ](OH) 2 。
(2) According to the mole ratio of 2.1:1 LiOH.H 2 O、[Ni 0.0.99 Al 0.001 ](OH) 2 After being uniformly mixed, a certain amount of B is added 2 O 3 Mixing, enabling the doping amount of B to be 0.5% of that of the lithium-rich material, ball milling for 60min at 25Hz, then preserving heat at 450 ℃ for 2h, preserving heat at 650 ℃ for 15h in an argon atmosphere, and carrying out high-temperature solid-phase reaction at a heating rate of 5 ℃/min to obtain the inner core Al of the lithium-rich material doped with Al element in a gradient manner and doped with B element G -B-Li 2 NiO 2 。
(3) Al is added with G -B-Li 2 NiO 2 Ball milling with 2wt% glucose at 25Hz for 30min, sintering in nitrogen atmosphere at 650 deg.c for 4 hr at 2 deg.c/min; finally, the lithium supplementing material with gradient doping of Al element, doping of B element and carbon coating is obtained.
Example 2
The embodiment provides a lithium supplementing material and a preparation method thereof, wherein the lithium supplementing material comprises a lithium-rich material inner core Li 2 NiO 2 The lithium-rich material is coated with an inner core Li 2 NiO 2 The carbon layer (packaging layer) on the outer surface, the inner core of the lithium-rich material is doped with Al element and B element, and the content of Al gradually increases from the core of the inner core of the lithium-rich material to the surface.
The preparation method of the lithium supplementing material comprises the following steps:
(1) The same as in step (1) of example 1, except that the Al doping amount was 5% by mass of the lithium-rich material, the precursor obtained by gradient doping with Al element was [ Ni ] 0.95 Al 0.05 ](OH) 2 。
(2) The same as in the step (2) of example 1, except that the B doping amount was 2% by mass of the lithium-rich material, to obtain an Al-element gradient-doped, B-element doped lithium-rich material core Al G -B-Li 2 NiO 2 。
Example 3
The embodiment provides a lithium supplementing material and a preparation method thereof, wherein the lithium supplementing material comprises a lithium-rich material inner core Li 2 NiO 2 The lithium-rich material is coated with an inner core Li 2 NiO 2 Carbon layer (packaging layer) on outer surface, and inner core of lithium-rich material doped with Al elementAnd B element, wherein the content of Al gradually increases from the core of the lithium-rich material core to the surface.
The preparation method of the lithium supplementing material comprises the following steps:
(1) The same as in step (1) of example 1, except that the Al doping amount was 7% by mass of the lithium-rich material, the precursor obtained by gradient doping with Al element was [ Ni ] 0.95 Al 0.05 ](OH) 2 。
(2) The same as in the step (2) of example 1, except that the B doping amount was 3% by mass of the lithium-rich material, to obtain an Al-element gradient-doped, B-element doped lithium-rich material core Al G -B-Li 2 NiO 2 。
Example 4
The embodiment provides a lithium supplementing material and a preparation method thereof, wherein the lithium supplementing material comprises a lithium-rich material inner core Li 2 NiO 2 The lithium-rich material is coated with an inner core Li 2 NiO 2 The carbon layer (packaging layer) on the outer surface, the inner core of the lithium-rich material is doped with Bi element and Sb element, and the Bi content gradually increases from the core of the inner core of the lithium-rich material to the surface.
The preparation method of the lithium supplementing material comprises the following steps:
(1) The preparation method is the same as in step (1) of example 1, except that Al 2 (SO 4 ) 3 Conversion to Bi 2 (SO 4 ) 3 Preparing a precursor [ Ni ] doped with Bi element in gradient mode 0.99 Bi 0.001 ](OH) 2 。
(2) According to the mole ratio of 2.1:1 LiOH.H 2 O、[Ni 0.99 Bi 0.001 ](OH) 2 Mixing, adding Sb of a certain mass 2 O 3 Mixing, enabling the doping amount of Sb to be 0.5% of that of the lithium-rich material, ball-milling for 60min at 25Hz, then preserving heat at 500 ℃ for 2h and at 750 ℃ for 16h in an argon atmosphere, and carrying out high-temperature solid-phase reaction at a heating rate of 5 ℃/min to obtain the Bi element gradient doped and Sb element doped lithium-rich material inner core Bi G -Sb-Li 2 NiO 2 。
(3) Bi is mixed with G -Sb-Li 2 NiO 2 With 2wt% of grapeBall milling sugar for 30min at 25Hz, sintering in nitrogen atmosphere at 650 deg.c for 5 hr at 2 deg.c/min; finally, the lithium supplementing material with the carbon coating and the Bi element gradient doping and the Sb element doping is obtained.
Example 5
The embodiment provides a lithium supplementing material and a preparation method thereof, wherein the lithium supplementing material comprises a lithium-rich material inner core Li 2 NiO 2 The lithium-rich material is coated with an inner core Li 2 NiO 2 The carbon layer (packaging layer) on the outer surface, the inner core of the lithium-rich material is doped with Bi element and Sb element, and the Bi content gradually increases from the core of the inner core of the lithium-rich material to the surface.
(1) The preparation method is the same as in (1) of example 4, except that the Bi doping amount is different, the doping amount is 10%, and the prepared Bi element gradient doped precursor is [ Ni ] 0.90 Bi 0.10 ](OH) 2 。
(2) The preparation method is the same as in (2) of example 4, except that the doping amount of Sb is different and 5%, and the inner core of the obtained Bi element gradient doped and Sb element doped lithium-rich material is Bi G -Sb-Li 2 NiO 2 。
(3) The preparation method is the same as in the step (3) in example 4.
Example 6
The embodiment provides a lithium supplementing material and a preparation method thereof, wherein the lithium supplementing material comprises a lithium-rich material inner core Li 2 NiO 2 The lithium-rich material is coated with an inner core Li 2 NiO 2 The carbon layer (packaging layer) on the outer surface, the inner core of the lithium-rich material is doped with Al element and B element, but the content of the Al element and the content of the B element have no change rule.
The preparation method of the lithium supplementing material is different from example 1 in that 0.1mol/L of Al is not used in the step (1) 2 (SO 4 ) 3 An aqueous solution (first solution A) and 1mol/L of Al 2 (SO 4 ) 3 The obtained precursor is Ni (OH) 2 . In the step (2), the molar ratio is 2.1:1:0.02:0.02 LiOH.H 2 O、Ni(OH) 2 、B 2 O 3 And Al (OH) 3 ·3H 2 O is mixed, and the obtained lithium-rich material core is Al-B-Li 2 NiO 2 。
Comparative example 1
This comparative example provides a lithium supplementing material comprising a lithium rich material core Li 2 NiO 2 The lithium-rich material is coated with an inner core Li 2 NiO 2 The carbon layer (encapsulation layer) on the outer surface was not doped with Al element and B element in this comparative example, as compared with example 1.
The preparation method of the lithium supplementing material is different from example 1 in that 0.1mol/L of Al is not used in the step (1) 2 (SO 4 ) 3 An aqueous solution (first solution A) and 1mol/L of Al 2 (SO 4 ) 3 The obtained precursor is Ni (OH) 2 。
Comparative example 2
This comparative example provides a lithium supplementing material comprising a lithium rich material core Li 2 NiO 2 The lithium-rich material is coated with an inner core Li 2 NiO 2 The carbon layer (encapsulation layer) on the outer surface was doped with Al element and not doped with B element in this comparative example, as compared with example 1.
The preparation method of the lithium supplementing material is different from example 1 in that step (2) is not used.
Comparative example 3
This comparative example provides a lithium supplementing material comprising a lithium rich material core Li 2 NiO 2 The lithium-rich material is coated with an inner core Li 2 NiO 2 The carbon layer (encapsulation layer) on the outer surface was doped with B element without doping Al element in the comparative example, compared with example 1.
The preparation method of the lithium supplementing material is different from example 1 in that step (1) is not used.
Characterization of materials
Scanning electron microscopy tests were performed on the lithium rich material cores of example 1 and comparative example 1, respectively, to characterize their particle size ranges.
The lithium supplementing materials provided in examples 1 to 6 and comparative examples 1 to 3 described above were assembled into a positive electrode and a lithium ion battery, respectively, as follows:
positive electrode: mixing a lithium supplementing material and lithium iron phosphate according to the mass ratio of 4:96 to obtain a mixture, mixing the mixture, polyvinylidene fluoride and SP-Li according to the mass ratio of 93:3:4, ball-milling and stirring to obtain positive electrode slurry, coating the positive electrode slurry on the surface of an aluminum foil, vacuum-drying at 110 ℃ for overnight, and rolling to obtain a positive electrode plate;
and (3) a negative electrode: graphite with carboxymethylcellulose (CMC), SBR and SP according to 95.8: mixing, ball milling and stirring in a mass ratio of 1.2:2:1 to obtain negative electrode slurry, coating the negative electrode slurry on the surface of a copper foil, and vacuum drying overnight at 110 ℃ to obtain a negative electrode plate;
electrolyte solution: mixing ethylene carbonate and ethylmethyl carbonate in a volume ratio of 3:7, and adding LiPF 6 Forming electrolyte, wherein the concentration of LiPF6 is 1mol/L;
a diaphragm: a polypropylene microporous separator;
and (3) assembling a lithium ion battery: and assembling the button type lithium ion full battery in an inert atmosphere glove box according to the assembling sequence of the graphite negative electrode plate, the diaphragm, the electrolyte and the positive electrode plate.
The electrochemical properties of each of the lithium ion batteries assembled in the above lithium ion battery examples were individually subjected to the performance test as in table 1,
performance testing
The performance parameters of the specific charge capacity, specific discharge capacity and capacity retention rate of the battery are respectively measured for each lithium ion battery assembled in the lithium ion battery embodiment, and the test conditions are as follows: the battery is tested in a cabinet at 25 ℃, the test voltage range is set to be 2.0.0-4.25V, the first charge and discharge are carried out at the test current of 0.05C, and the circulation test is carried out at the test current of 0.2C.
The test results are shown in table 1 below:
TABLE 1
As can be seen from the test results of examples 1-6 and comparative examples 1-3 in Table 1, the lithium-rich material containing two element doped carbon layers in the examples has a much higher first charge-discharge capacity than that in the comparative examples, and the first charge capacity can be up to 450.3mAh/g, and the first discharge capacity is not lower than 140 mAh/g. Meanwhile, as can be seen from the test results of the embodiment 1 and the comparative examples 1 to 3, the first element and the second element can have obvious synergistic effects, and the conductivity of the material can be greatly improved by doping metal and metalloid, so that the lithium supplementing material has more excellent charge and discharge performance. Moreover, as can be seen from examples 1 and 6, the effect of adding the first element in the core in a gradient doping manner is better, and the specific charge capacity and specific discharge capacity are both obviously improved, which also indicates that the gradient doping manner can improve the structural stability of the lithium-supplementing material and finally improve the cycle performance of the lithium-supplementing material.
Therefore, the first element and the second element are doped in the inner core of the lithium-rich material, the contents of the first element and the second element are changed in a gradient manner from the core of the lithium-rich material to the surface, the cycling stability of the lithium-supplementing material can be improved, the side reaction between the inner core of the lithium-rich material and the electrolyte is avoided, the capacity attenuation can be effectively relieved, and the cycling performance of the lithium-supplementing material is improved. Further, the packaging layer is used for coating the lithium-rich material inner core, so that the electronic and ion conduction performance of the lithium-rich material inner core can be effectively improved, and the lithium release in the charging process is improved; can also play a certain role in isolating moisture, improve the stability of the lithium supplementing material and realize a stable lithium supplementing effect.
In addition, as can be seen from the characterization of fig. 4A, the D50 particle size of the lithium-rich material core of comparative example 1 is about 25 μm, while as can be seen from the characterization of fig. 4B, the D50 particle size of the lithium-rich material core of example 1 is about 5 μm. Therefore, compared with the lithium-rich material core without the doped Al element and B element, the particle size of the lithium-rich material core doped with the Al element and B element is obviously reduced. Further, it can also be seen from the specific charge/discharge capacities of comparative example 1 and comparative example 1 that the specific charge/discharge capacity of the battery corresponding to the core of the lithium-rich material doped with Al element and B element was significantly improved. Therefore, the electron structure and the space configuration of the active site of the inner core of the lithium-rich material can be regulated and controlled by co-doping of metal elements and metalloid elements, particles are thinned, the diffusion speed of lithium ions is improved, and the reversible capacity of the material is improved.
In the description of the embodiments of the present application, it should be noted that, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like refer to the orientation or positional relationship described based on the drawings, which are merely for convenience of description and simplification of the description, and do not indicate or imply that the apparatus or element in question must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.
The above disclosure is only a preferred embodiment of the present application, and it should be understood that the scope of the application is not limited thereto, but all or part of the procedures for implementing the above embodiments can be modified by one skilled in the art according to the scope of the appended claims.

Claims (12)

1. The lithium supplementing material is characterized by comprising a lithium-rich material core, and a first element and a second element which are doped in the lithium-rich material core, wherein the first element is a metal main group element, and the second element is a metalloid element.
2. The lithium-supplementing material of claim 1, wherein the lithium-rich material core has a chemical formula of Li x M y O z Wherein x is more than or equal to 2 and less than or equal to 6, y is more than or equal to 1 and less than or equal to 5, z is more than or equal to 2 and less than or equal to 8, and M is at least one of V, mn, fe, co, ni, cu, zrAn element, the first element comprising at least one element of Al, ga, in, tl, sn, bi and the second element comprising at least one element of B, si, ge, as, sb, te.
3. The lithium-supplementing material according to claim 1, wherein the content of the first element gradually increases from the core of the lithium-rich material core to the outer surface of the lithium-rich material core.
4. The lithium supplementing material according to claim 1, wherein the mass fraction of the first element in the lithium-rich material core is 0.1-10%; the mass fraction of the second element in the lithium-rich material core is 0.5% -5%.
5. The lithium-supplementing material according to claim 1, wherein the lithium-rich material core comprises a plurality of single crystal particles, and the single crystal particles have a particle size ranging from 2nm to 20nm.
6. The lithium-supplementing material according to claim 1, wherein the D50 particle size of the lithium-rich material core is in the range of 5nm to 10 μm.
7. The lithium supplementing material according to claim 1, further comprising an encapsulation layer, wherein the encapsulation layer is coated on the outer surface of the lithium-rich material core, and the thickness of the encapsulation layer is 2 nm-100 nm.
8. The preparation method of the lithium supplementing material is characterized by comprising the following steps:
adding a main body solution, a first solution and a precipitant into a substrate solution, and reacting to obtain a first precursor, wherein the first solution comprises a first element which is a metal main group element;
and mixing the first precursor, a lithium source and a second precursor, and then performing high-temperature reaction to obtain the lithium-rich material core, wherein the second precursor comprises a second element, and the second element is a metalloid element.
9. The method for preparing a lithium supplementing material according to claim 8, wherein the base solution is at least one of ammonia water, citric acid or ethylenediamine; the precipitant is at least one of hydroxide, carbonate or oxalate; the first solution is a metal ion aqueous solution comprising the first element; the second precursor is a metalloid oxide including the second element.
10. A positive electrode material comprising a positive electrode active material and the lithium supplementing material according to any one of claims 1 to 7.
11. A positive electrode sheet comprising the positive electrode material according to claim 10.
12. A secondary battery comprising the positive electrode sheet according to claim 11.
CN202310151833.7A 2023-02-10 2023-02-10 Lithium supplementing material, preparation method thereof, positive plate and secondary battery Pending CN116598491A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310151833.7A CN116598491A (en) 2023-02-10 2023-02-10 Lithium supplementing material, preparation method thereof, positive plate and secondary battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310151833.7A CN116598491A (en) 2023-02-10 2023-02-10 Lithium supplementing material, preparation method thereof, positive plate and secondary battery

Publications (1)

Publication Number Publication Date
CN116598491A true CN116598491A (en) 2023-08-15

Family

ID=87603253

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310151833.7A Pending CN116598491A (en) 2023-02-10 2023-02-10 Lithium supplementing material, preparation method thereof, positive plate and secondary battery

Country Status (1)

Country Link
CN (1) CN116598491A (en)

Similar Documents

Publication Publication Date Title
CN110050366B (en) Nickel active material precursor, method for producing same, nickel active material, and lithium secondary battery
KR102026918B1 (en) Preparation method of positive electrode active material for lithium secondary battery and positive electrode active material for lithium secondary battery prepared by using the same
US20230268503A1 (en) Nickel-based active material precursor for lithium secondary battery, method of preparing the same, nickel-based active material for lithium secondary battery formed therefrom, and lithium secondary battery including positive electrode including nickel-based active material
CN112088451B (en) Method for producing carbon nanostructure containing molybdenum disulfide, positive electrode for lithium secondary battery, and lithium secondary battery
CN111193019B (en) Lithium supplement additive, preparation method thereof and lithium ion battery
KR20220092556A (en) Anode active material for battery and manufacturing method thereof, battery negative electrode, battery
WO2020143531A1 (en) Positive electrode active material and preparation method therefor, sodium ion battery, and device comprising sodium ion battery
CN111342031B (en) Multi-element gradient composite high-first-efficiency lithium battery negative electrode material and preparation method thereof
CN113555557B (en) Lithium iron phosphate positive electrode material, preparation method and application thereof
CN113479944A (en) Preparation method of modified high-nickel ternary cathode material
KR20180138133A (en) METHOD FOR PREPARING FeOOH, AND CATHODE FOR LITHIUM-SULFUR BATTERY COMPRISING FeOOH
CN111886724A (en) Positive electrode active material for lithium secondary battery, method for producing same, and lithium secondary battery comprising same
JP2013225471A (en) Cathode active material for secondary battery and method for producing the same
CN115295795A (en) Positive electrode lithium supplement additive and preparation method and application thereof
CN116014104A (en) Lithium-rich nickel positive electrode material, preparation method thereof, positive electrode sheet and secondary battery
CN106602046B (en) Silicate positive electrode material of lithium ion battery and preparation and application thereof
EP3806207A1 (en) Method for preparing iron sulfide, cathode comprising iron sulfide prepared thereby for lithium secondary battery, and lithium secondary battery comprising same
CN110931763A (en) Lithium ion battery anode material and preparation method and application thereof
CN112928246A (en) Composite material, preparation method and application thereof
CN111755670A (en) Negative electrode material of lithium battery, preparation method and application
CN115636402B (en) Lithium iron manganese phosphate material and preparation method and application thereof
CN112186166A (en) Molybdenum/cobalt oxide-carbon composite material and preparation method thereof, lithium ion battery negative electrode piece and lithium ion battery
CN116598449A (en) Lithium-rich positive electrode material, preparation method thereof, positive electrode plate and secondary battery
CN115020695A (en) Positive electrode active material, electrochemical device, and electronic device
CN116598491A (en) Lithium supplementing material, preparation method thereof, positive plate and secondary battery

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination