CN115611254A - Lithium manganese iron phosphate precursor, lithium manganese iron phosphate, preparation methods of lithium manganese iron phosphate precursor and lithium manganese iron phosphate, electrode and battery - Google Patents

Lithium manganese iron phosphate precursor, lithium manganese iron phosphate, preparation methods of lithium manganese iron phosphate precursor and lithium manganese iron phosphate, electrode and battery Download PDF

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CN115611254A
CN115611254A CN202211116752.5A CN202211116752A CN115611254A CN 115611254 A CN115611254 A CN 115611254A CN 202211116752 A CN202211116752 A CN 202211116752A CN 115611254 A CN115611254 A CN 115611254A
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manganese
lithium
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precursor
iron phosphate
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陈士磊
陈晓军
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Quzhou Huayou Cobalt New Material Co ltd
Zhejiang Huayou Cobalt Co Ltd
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Quzhou Huayou Cobalt New Material Co ltd
Zhejiang Huayou Cobalt Co Ltd
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Abstract

The application relates to the technical field of batteries, and provides a preparation method of a lithium manganese iron phosphate precursor, which comprises the following steps: preparing a ferro-manganese intermediate: providing a first iron source and a first manganese source, and preparing a first ferro-manganese intermediate; mixing material treatment: mixing the first iron-manganese intermediate, the first phosphorus source, the first lithium source and the first carbon source to obtain a mixture; grinding treatment: grinding the mixture; the pretreatment step comprises: pretreating the ground mixture to obtain a lithium manganese iron phosphate precursor; the preparation method of the lithium ferric manganese phosphate precursor further comprises the following steps: providing a reaction precursor for preparing a lithium ferric manganese phosphate precursor, and adding the reaction precursor in at least one step of preparing a ferric manganese phosphate intermediate, mixing, grinding and pretreating, and carrying out corresponding treatment. The preparation method of the lithium manganese iron phosphate precursor can realize the customization of the lithium manganese iron phosphate anode material and meet the performance requirements of different sides of the lithium manganese iron phosphate.

Description

Lithium manganese iron phosphate precursor, lithium manganese iron phosphate, preparation methods of lithium manganese iron phosphate precursor and lithium manganese iron phosphate, electrode and battery
Technical Field
The application belongs to the technical field of batteries, and particularly relates to a lithium manganese iron phosphate precursor, lithium manganese iron phosphate and preparation methods thereof, an electrode and a battery.
Background
Lithium manganese iron phosphate is used as an upgraded version of lithium iron phosphate, and is a novel anode material obtained by adding a manganese element on the basis of the lithium iron phosphate. Lithium manganese iron phosphate has a higher voltage platform than lithium iron phosphate, the energy density can be about 15% higher than that of the lithium manganese iron phosphate, and the safety and low-cost characteristics of the lithium iron phosphate are kept.
The existing method for preparing the lithium manganese iron phosphate anode material comprises two major methods, wherein the first method can be called as a one-step method, and comprises the steps of mixing an iron source, a manganese source, a phosphorus source, a lithium source and a carbon source, carrying out certain reaction and treatment to obtain a lithium manganese iron phosphate precursor, and roasting and crushing to obtain the lithium manganese iron phosphate anode material; common one-step methods include sol-gel methods, hydrothermal methods, sand-sand mixed solid phase methods, and the like. The second type can be called a two-step method, which comprises the steps of firstly preparing a ferro-manganese intermediate, then mixing and sanding the ferro-manganese intermediate with a phosphorus source, a lithium source and a carbon source, drying and pretreating to obtain a lithium manganese iron phosphate precursor, and then roasting and post-treating to obtain the lithium manganese iron phosphate cathode material.
The lithium manganese iron phosphate precursors prepared by different methods have different characteristics, such as element distribution, particle size distribution, primary particle morphology, secondary particle morphology, specific surface area, moisture, ignition loss rate and the like, and further, the different characteristics can influence element diffusion, nucleation crystallization, particle growth, carbon coating and the like during roasting, so that the obtained lithium manganese iron phosphate has different performance characteristics. Therefore, the performance requirements of different sides of the lithium manganese iron phosphate are difficult to meet with the existing preparation method.
Disclosure of Invention
The application aims to provide a lithium manganese iron phosphate precursor, lithium manganese iron phosphate and preparation methods thereof, an electrode and a battery, and aims to solve the problem that the existing preparation method is difficult to meet performance requirements of different sides of lithium manganese iron phosphate.
In order to achieve the purpose of the application, the technical scheme adopted by the application is as follows:
in a first aspect, the present application provides a method for preparing a lithium manganese iron phosphate precursor, including:
preparing a ferro-manganese intermediate: providing a first iron source and a first manganese source, and preparing a first ferro-manganese intermediate;
mixing material treatment: mixing the first iron-manganese intermediate, the first phosphorus source, the first lithium source and the first carbon source to obtain a mixture;
grinding treatment: grinding the mixture;
the pretreatment step comprises: pretreating the ground mixture to obtain a lithium manganese iron phosphate precursor;
the preparation method of the lithium ferric manganese phosphate precursor further comprises the following steps: providing a reaction precursor for preparing a lithium manganese iron phosphate precursor, and adding the reaction precursor and performing corresponding treatment in at least one of the steps of preparing the intermediate, mixing, grinding and pre-treating.
Further, the reaction precursor is added in the step of preparing the ferromanganese intermediate, which comprises: providing a first iron source and a first manganese source; mixing the first iron source, the first manganese source and the reaction precursor to prepare a mixed precipitate containing a first ferromanganese intermediate and the reaction precursor; wherein the reaction precursor comprises a second ferro-manganese intermediate; and in the step of grinding treatment, mixing the mixed precipitate, the first phosphorus source, the first lithium source and the first carbon source to obtain a mixture.
Further, the first iron source comprises a ferrous sulfate solution, the first manganese source comprises a manganese sulfate solution, and the second ferromanganese intermediate comprises a ferromanganese oxalate intermediate.
Further, the reaction precursor is added in the step of mixing, and the step of mixing treatment comprises the following steps: mixing the first iron-manganese intermediate, the first phosphorus source, the first lithium source, the first carbon source and the reaction precursor to obtain a mixture; wherein the reaction precursor comprises a second iron source, a second manganese source, a second phosphorus source, a second lithium source and a second carbon source.
Further, the reactive precursor is added in the step of milling, and the step of milling treatment comprises: grinding the mixture, adding the reaction precursor into the mixture and continuing grinding; wherein the reaction precursor comprises a third phosphorus source, a third lithium source, a third carbon source and a third ferromanganese intermediate.
Further, the first ferromanganese intermediate is a ferromanganese phosphate intermediate, and the third ferromanganese intermediate is a ferromanganese oxalate intermediate.
Further, the reactive precursor is added in the step of pre-treating, which comprises: preprocessing the mixture to obtain a first lithium manganese iron phosphate precursor, and mixing the first lithium manganese iron phosphate precursor with the reaction precursor to obtain a lithium manganese iron phosphate precursor; wherein the reaction precursor comprises a second lithium ferric manganese phosphate precursor.
Further, preparing the second lithium ferric manganese phosphate precursor comprises: and mixing, grinding and drying a fourth iron source, a fourth manganese source, a fourth phosphorus source, a fourth lithium source and a fourth carbon source to obtain the second lithium manganese iron phosphate precursor.
In a second aspect, the present application provides a lithium manganese iron phosphate precursor, where the lithium manganese iron phosphate precursor is prepared according to the method provided in the first aspect of the present application.
In a third aspect, the present application provides a method for preparing lithium iron manganese phosphate, comprising: the lithium manganese iron phosphate precursor provided by the first aspect of the present application is calcined to obtain lithium manganese iron phosphate.
In a fourth aspect, the present application provides a lithium manganese phosphate, which is prepared according to the method provided in the third aspect of the present application.
Further, the lithium manganese iron phosphate has the structure asThe general formula is as follows: li (1+x) (Fe+Mn) y PO 4 /zC，0<x<0.02，0.95<y<1，0.5wt％<z<3wt％。
Further, the lithium manganese iron phosphate has the following general formula: li (1+x) (Fe+Mn) y M p PO 4 /zC，0<x<0.02，0.95<y<1，0<p<0.01，0.5wt％<z<3wt%, wherein M represents a doping element.
In a fifth aspect, the present application provides an electrode comprising lithium manganese iron phosphate as provided in the fourth aspect of the present application.
In a sixth aspect, the present application provides a battery comprising an electrode as provided in the fifth aspect of the present application.
The preparation method of the lithium manganese iron phosphate precursor provided by the first aspect of the application is based on a two-step method, and can realize the adjustment of the characteristics of the precursor by selecting the reaction precursor to be added in different steps of the two-step method and utilizing the process difference caused by the supplementation of the reaction precursor in different processes and/or the difference of the characteristics of the supplemented reaction precursor, thereby realizing the controllability of the roasting process and achieving the accurate regulation and control of the performance of the lithium manganese iron phosphate. Therefore, the preparation method of the lithium manganese iron phosphate precursor provided in the first aspect of the embodiment of the present application can achieve customization of the lithium manganese iron phosphate positive electrode material, and meet performance requirements of different sides of the lithium manganese iron phosphate.
The lithium manganese iron phosphate precursor provided by the method in the second aspect of the application can realize performance regulation and control of lithium manganese iron phosphate in the roasting process, and meets performance requirements of different sides of lithium manganese iron phosphate.
According to the preparation method of the lithium iron manganese phosphate provided by the third aspect of the application, the customization of the lithium iron manganese phosphate can be realized according to requirements, so that the selection range of raw materials for preparing the lithium iron manganese phosphate anode material is expanded, and the product cost is stabilized.
The lithium manganese iron phosphate provided by the fourth aspect of the application has two or more substructures, has various performance advantages, and can meet the performance requirements of different sides.
The electrode provided by the fifth aspect of the present application has both cost and performance advantages.
The battery provided by the sixth aspect of the present application has both cost and performance advantages.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a flow chart illustrating a method for preparing lithium iron manganese phosphate according to an embodiment of the present disclosure;
FIG. 2 is a Scanning Electron Microscope (SEM) image of lithium manganese iron phosphate provided in example 1 of the present application;
FIG. 3 is a Scanning Electron Microscope (SEM) image of lithium manganese iron phosphate provided in comparative example 1;
FIG. 4 is a Scanning Electron Microscope (SEM) image of lithium manganese iron phosphate provided in comparative example 2;
fig. 5 is a charging and discharging test curve diagram of lithium ferric manganese phosphate at 0.1C for a charging and discharging function provided in embodiment 1 of the present application;
FIG. 6 is a plot of a 0.1C chargeback charge-discharge test for lithium manganese iron phosphate provided in comparative example 1;
fig. 7 is a plot of a 0.1C chargeback charge-discharge test for lithium manganese iron phosphate provided in comparative example 2.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application more clearly apparent, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
In this application, the term "and/or" describes an association relationship of associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a alone, A and B together, and B alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.
In this application, "at least one" means one or more, "a plurality" means two or more. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, "at least one (a), b, or c", or "at least one (a), b, and c", may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, and c may be single or plural, respectively.
It should be understood that, in various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, some or all of the steps may be executed in parallel or executed sequentially, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.
The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The weight of the related components mentioned in the description of the embodiments of the present application may not only refer to the specific content of each component, but also represent the proportional relationship of the weight among the components, and therefore, the content of the related components is scaled up or down within the scope disclosed in the description of the embodiments of the present application as long as it is scaled up or down according to the description of the embodiments of the present application. Specifically, the mass described in the specification of the examples of the present application may be a mass unit known in the chemical field such as μ g, mg, g, kg, etc.
The terms "first" and "second" are used for descriptive purposes only and are used for distinguishing purposes such as substances from one another, and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. For example, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX, without departing from the scope of embodiments of the present application. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
A first aspect of the embodiments of the present application provides a method for preparing a lithium ferric manganese phosphate precursor, including:
s10, preparing a ferro-manganese intermediate: providing a first iron source and a first manganese source, and preparing a first ferro-manganese intermediate;
s20, mixing material treatment: mixing the first ferro-manganese intermediate, the first phosphorus source, the first lithium source and the first carbon source to obtain a mixture;
s30, grinding: grinding the mixture;
s40, preprocessing: pretreating the ground mixture to obtain a lithium manganese iron phosphate precursor;
the preparation method of the lithium ferric manganese phosphate precursor further comprises the following steps: providing a reaction precursor for preparing a lithium ferric manganese phosphate precursor, and adding the reaction precursor in at least one of the steps of preparing a ferric manganese intermediate, mixing, grinding and pretreating, and carrying out corresponding treatment.
According to the preparation method of the lithium manganese iron phosphate precursor provided by the first aspect of the embodiment of the application, based on the two-step method, the characteristics of the precursor can be adjusted by selecting the reaction precursor to be added in different steps of the two-step method and utilizing the process difference caused by the addition of the reaction precursor in different processes and/or the difference of the characteristics of the addition of the reaction precursor, so that the adjustability of the roasting process is realized, and the accurate regulation and control of the performance of the lithium manganese iron phosphate is achieved. Therefore, the preparation method of the lithium manganese iron phosphate precursor provided in the first aspect of the embodiment of the present application can achieve customization of the lithium manganese iron phosphate positive electrode material, and meet performance requirements of different sides of the lithium manganese iron phosphate.
In some embodiments, the method for preparing the lithium ferric manganese phosphate precursor adds the reaction precursor in the step of preparing the ferromanganese intermediate. The step S10 specifically includes: providing a first iron source and a first manganese source; mixing a first iron source, a first manganese source and a reaction precursor to prepare a mixture containing a first ferro-manganese intermediate and a counter-reactionA mixed precipitate of the precursors; wherein the reaction precursor comprises a second ferromanganese intermediate. Then the above step S20 includes mixing the mixed precipitate, the first phosphorus source, the first lithium source and the first carbon source to obtain a mixed material. Optionally, the amounts of the mixed precipitate, the first phosphorus source, the first lithium source and the first carbon source in the mixture are proportioned according to a component formula: li (1+x) (Fe+Mn) y PO 4 /zC，0<x<0.02，0.95<y<1，0.5wt％<z<3wt%. And then grinding and drying the mixture to obtain the lithium manganese iron phosphate precursor. According to the embodiment of the application, the second ferromanganese intermediate is added in the step of preparing the ferromanganese intermediate in the two-step method, and the characteristics of the lithium manganese iron phosphate precursor are adjusted by utilizing different components, physical characteristics, morphologies and/or mixing forms of the generated first ferromanganese intermediate and the added second ferromanganese intermediate during mixing and precipitation and combining with subsequent grinding, and then the performance of the lithium manganese iron phosphate anode material is adjusted by combining with subsequent roasting.
It should be noted that in the examples of the present application, the iron source is a compound providing an iron element, the manganese source is a compound providing an iron element, the phosphorus source is a compound providing a phosphorus element, the lithium source is a compound providing a lithium element, and the carbon source is a compound providing a carbon element; the terms "first" and "second" are used for descriptive purposes only and do not denote a distinct category.
In some embodiments, the first ferric manganese intermediate comprises at least one of a ferrous manganese oxalate intermediate, a ferrous manganese ammonium phosphate intermediate, a ferrous manganese hydroxyphosphate intermediate. The second ferromanganese intermediate comprises at least one of a ferromanganese oxalate intermediate, a ferromanganese ammonium phosphate intermediate, a ferromanganese phosphate intermediate, and a hydroxyl ferromanganese phosphate intermediate. It is to be understood that the first and second ferromanganese intermediates herein can be the same type of ferromanganese intermediate or can be different types of ferromanganese intermediate. For example, in some embodiments, the first and second ferromanganese intermediates are different kinds of ferromanganese intermediates, wherein the first ferromanganese intermediate is a ferromanganese phosphate intermediate and the second ferromanganese intermediate is a ferromanganese oxalate intermediate; in some embodiments, the first ferromanganese intermediate and the second ferromanganese intermediate are of the same kind, wherein the first ferromanganese intermediate is a ferromanganese oxalate intermediate with a loose structure, and the second intermediate is a ferromanganese oxalate intermediate with a compact structure; in some embodiments, the first and second ferromanganese intermediates are of the same type and have different morphologies, wherein the first ferromanganese intermediate is a large-particle ferromanganese oxalate intermediate, and the second ferromanganese intermediate is a small-particle ferromanganese oxalate intermediate.
In some embodiments, the first iron source comprises an iron salt, such as a ferrous sulfate solution; the first manganese source comprises a manganese salt, such as a manganese sulfate solution; the second ferromanganese intermediate comprises a ferromanganese oxalate intermediate. The preparation method of the ferro-manganese intermediate comprises the following steps: uniformly mixing the ferrous sulfate solution and the manganese sulfate solution to obtain a ferrous manganese sulfate mixed solution, continuously and uniformly mixing the ferrous manganese sulfate mixed solution with a ferrous manganese oxalate intermediate, then precipitating the ferrous manganese sulfate mixed solution with a mixed solution of ammonium dihydrogen phosphate and ammonia water, filtering and drying to obtain a mixed precipitate containing a ferrous manganese phosphate intermediate and a ferrous manganese oxalate intermediate. Specifically, the obtained mixed precipitate is a ferrous manganese oxalate intermediate with a loose outer layer and a compact inner layer, and the ferrous manganese phosphate intermediate wraps the inner layer. In the embodiment, a two-step process of manganese iron phosphate is adopted, and the manganese iron oxalate intermediate is added when the manganese iron phosphate intermediate is prepared, so that a combined manganese iron intermediate with a loose outer layer and a compact inner layer can be formed, carbon sources in a lithium manganese iron phosphate precursor formed after spray drying are distributed more widely and uniformly, and the compaction density and the electrical property of the lithium manganese iron phosphate obtained after roasting and crushing are improved. Of course, in addition to the above-mentioned mixing precipitation in which the first and second ferrimanganese intermediates are mixed in a coated form, in other embodiments, the first and second ferrimanganese intermediates may also be mixed in a non-coated form, for example, by using different preparation processes and adjusting reaction conditions such that the first and second ferrimanganese intermediates are mixed and precipitated in a non-coated form. The coating and non-coating can be realized by the prior known means, and are not described in detail herein.
In some embodiments, the method for preparing the lithium manganese iron phosphate precursor adds the reaction precursor in the step of mixing. The step S20 specifically includes: mixing the first ferro-manganese intermediate, the first phosphorus source, the first lithium source, the first carbon source and the reaction precursor to obtain a mixture; wherein the reaction precursor comprises a second iron source, a second manganese source, a second phosphorus source, a second lithium source, and a second carbon source. And then, grinding and drying the mixture to obtain the lithium manganese iron phosphate precursor. Optionally, the amounts of the first iron-manganese intermediate, the first phosphorus source, the first lithium source and the first carbon source in the mixture are proportioned according to the component molecular formula, and the amounts of the second iron source, the second manganese source, the second phosphorus source, the second lithium source and the second carbon source in the mixture are proportioned according to the component molecular formula; the molecular formula of the components is as follows: li (1+x) (Fe+Mn) y PO 4 /zC，0<x<0.02，0.95<y<1，0.5wt％<z<3wt％。
According to the embodiment of the application, a second iron source, a second manganese source, a second phosphorus source, a second lithium source and a second carbon source are added in the step of mixing treatment in the two-step method, so that the grinding viscosity is reduced during subsequent grinding, and the compaction density of the lithium manganese iron phosphate obtained after roasting and crushing is improved. It can be understood that, in this embodiment, a one-step method and a two-step method are equivalently used for simultaneously preparing the lithium manganese iron phosphate precursor, and the prepared lithium manganese iron phosphate precursor has the advantages of the two preparation processes through advantage complementation. The second iron source and the first iron source may be the same species or different species, the second manganese source and the first manganese source may be the same species or different species, the second phosphorus source and the first phosphorus source may be the same species or different species, the second lithium source and the first lithium source may be the same species or different species, and the second carbon source and the first carbon source may be the same species or different species, which is not limited herein. Of course, in other embodiments, an intermediate of ferro manganese may be added during the compounding step.
In some embodiments, the method of preparing the lithium manganese iron phosphate precursor adds the reaction precursor during the milling step. The step S30 isThe body includes: grinding the mixture, adding the reaction precursor into the mixture and continuing grinding; wherein the reaction precursor comprises a third phosphorus source, a third lithium source, a third carbon source and a third ferromanganese intermediate. And then, drying the mixture obtained after grinding to obtain the lithium manganese iron phosphate precursor. Optionally, the amounts of a third phosphorus source, a third lithium source, a third carbon source and a third ferrimanganic intermediate in the mixture are also proportioned according to the component molecular formula; the molecular formula of the components is as follows: li (1+x) (Fe+Mn) y PO 4 /zC，0<x<0.02，0.95<y<1，0.5wt％<z<3wt％。
According to the embodiment of the application, a third phosphorus source, a third lithium source, a third carbon source and a third ferrimanganic intermediate are added in the grinding treatment step of the two-step method, so that the grinding degree of the later mixed material is different from that of the previously mixed material, and the particle size distribution range of the primary particles of the lithium ferric manganese phosphate obtained after roasting is improved. Here, the third ferrimanganic intermediate and the first ferrimanganic intermediate may be the same substance or different substances, the third phosphorus source and the first phosphorus source may be the same substance or different substances, the third lithium source and the first lithium source may be the same substance or different substances, and the third carbon source and the first carbon source may be the same substance or different substances, which is not limited herein.
In some embodiments, the first ferrimanganese intermediate is a ferrimanganese phosphate intermediate and the third ferrimanganese intermediate is a ferrimanganese oxalate intermediate. Specifically, a ferrous manganese phosphate intermediate is prepared by adopting a ferrous manganese phosphate process, the ferrous manganese oxalate intermediate and corresponding third phosphorus source, third lithium source and third carbon source, namely, a raw material of the ferro-manganese ferric phosphate process, are mixed in at the later stage of the step of sanding treatment, and the obtained lithium ferric manganese phosphate precursor is roasted and crushed to obtain lithium ferric manganese phosphate primary particles with wider particle size distribution and an obvious double-peak structure. The reason is that the original manganese ferrous phosphate intermediate is easier to grind than the manganese ferrous oxalate intermediate, and the grinding time of the added manganese ferrous oxalate intermediate is short, so that the particle size distribution of the finally obtained lithium manganese ferric phosphate primary particles is further widened.
In some embodiments, the method of preparing the lithium manganese iron phosphate precursor adds the reaction precursor in a pre-treatment step. The step S40 specifically includes: preprocessing the mixture to obtain a first lithium manganese iron phosphate precursor; mixing the first lithium manganese iron phosphate precursor with the reaction precursor to obtain a lithium manganese iron phosphate precursor; wherein the reaction precursor is a second lithium manganese iron phosphate precursor. It is understood that the lithium manganese iron phosphate precursor includes a first lithium manganese iron phosphate precursor and a second lithium manganese iron phosphate precursor. The pretreatment is a generic concept, which includes some treatment means after grinding, such as drying, and other different treatment means may be available for different reaction systems, which are not listed here. Optionally, the first lithium manganese iron phosphate precursor and the second lithium manganese iron phosphate precursor are prepared by different preparation processes, different process parameters and/or different formulations. Under the influence of different preparation processes, different process parameters and/or different formula preparations, the first lithium manganese phosphate precursor and the second lithium manganese phosphate precursor generally have different characteristics, the first lithium manganese phosphate precursor and the second lithium manganese phosphate precursor with different characteristics are mixed to prepare the lithium manganese phosphate precursor, and the first lithium manganese phosphate precursor and the second lithium manganese phosphate precursor are used for advantage complementation, so that the finally obtained lithium manganese phosphate precursor has the advantages of both the first lithium manganese phosphate precursor and the second lithium manganese phosphate precursor, the adjustability in the roasting process is further realized, and the obtained lithium manganese phosphate meets the performance requirements of different sides.
In some embodiments, providing the reaction precursor comprises preparing the reaction precursor, i.e., preparing a second lithium manganese iron phosphate precursor, optionally preparing the second lithium manganese iron phosphate precursor by a one-step method, and mixing the obtained second lithium manganese iron phosphate precursor with the first lithium manganese iron phosphate precursor prepared by the two-step method to obtain the lithium manganese iron phosphate precursor. Of course, in other embodiments, a two-step process may also be used to prepare the second lithium ferric manganese phosphate precursor.
In some embodiments, the one-step process includes a hydrothermal process, a sol-gel process, a sand-mixed-solid-phase process.
In some embodiments, a second phosphoric acid is preparedThe iron-manganese-lithium precursor comprises: and mixing, grinding and drying a fourth iron source, a fourth manganese source, a fourth phosphorus source, a fourth lithium source and a fourth carbon source to obtain a second lithium manganese iron phosphate precursor. Optionally, the amounts of the fourth iron source, the fourth manganese source, the fourth phosphorus source, the fourth lithium source and the fourth carbon source are also proportioned according to the component molecular formula; the molecular formula of the components is as follows: li (1+x) (Fe+Mn) y PO 4 /zC，0<x<0.02，0.95<y<1，0.5wt％<z<3wt%. The fourth iron source and the first iron source may be the same species or different species, the fourth manganese source and the first manganese source may be the same species or different species, the fourth phosphorus source and the first phosphorus source may be the same species or different species, the fourth lithium source and the first lithium source may be the same species or different species, and the fourth carbon source and the first carbon source may be the same species or different species, which is not limited herein.
In some embodiments, the reaction precursor may be added to participate in the preparation of the lithium manganese iron phosphate precursor in one of the steps of preparing the intermediate iron manganese, the step of mixing, the step of grinding, and the step of pre-treating, or may be added to participate in the preparation of the lithium manganese iron phosphate precursor in a plurality of the steps of preparing the intermediate iron manganese, the step of mixing, the step of grinding, and the step of pre-treating, and the reaction precursors added in each step may be the same or different.
In some embodiments, doping elements may be further added during the preparation of the lithium manganese iron phosphate precursor for doping, wherein the amounts of the iron source, the manganese source, the phosphorus source, the lithium source, the carbon source and the doping source are proportioned according to the formula of the components; the molecular formula of the components is as follows: li (1+x) (Fe+Mn) y M p PO 4 /zC，0<x<0.02，0.95<y<1，0<p<0.01，0.5wt％<z<3wt%, wherein M represents a doping element. Optionally, M comprises one or more doping elements of Mg, ca, co, ni, cu, zn, al, ga, sc, Y, la, ti, zr, V, nb, cr, mo.
In conclusion, in the invention, different reaction precursors are supplemented in different steps of synthesizing the lithium ferric manganese phosphate precursor by the two-step method to participate in the preparation of the lithium ferric manganese phosphate precursor, so that the performance of the precursor can be adjusted on different characteristic sides, the higher controllability of the roasting process can be realized, and the accurate regulation and control of the performance can be realized. For example, the primary particle size distribution grading composition can improve the compaction density, the composition of the element uniform distribution phase and the element non-uniform distribution phase can improve the manganese dissolution and the high-pressure platform attenuation problem, the composition of the easy-to-sinter particles and the difficult-to-sinter particles can improve the crystallinity of the primary particles and inhibit the generation of large particles, the composition of the doped phase and the undoped phase can realize the linear regulation of the performance, the composition of the carbon-rich particles and the carbon-poor particles can enhance the regulation and control capability of the size of the primary particles, and the like.
A second aspect of the embodiments of the present application provides a lithium manganese iron phosphate precursor, where the lithium manganese iron phosphate precursor is prepared according to the preparation method of the lithium manganese iron phosphate precursor provided in the first aspect of the embodiments of the present application.
The lithium manganese iron phosphate precursor provided by the second aspect of the embodiment of the application can realize performance regulation and control of lithium manganese iron phosphate in the roasting process.
A third aspect of the embodiments of the present application provides a method for preparing lithium iron manganese phosphate, including: and roasting the lithium manganese iron phosphate precursor provided by the second aspect of the embodiment of the application to obtain the lithium manganese iron phosphate.
The preparation method of lithium iron manganese phosphate provided by the third aspect of the embodiment of the application can realize customization of lithium iron manganese phosphate according to requirements, so that the raw material selection range for preparing the lithium iron manganese phosphate cathode material is expanded, and the product cost is stabilized.
The fourth aspect of the embodiment of the present application provides lithium manganese phosphate, which is prepared according to the method for preparing lithium manganese phosphate provided by the third aspect of the embodiment of the present application.
The lithium manganese iron phosphate provided by the fourth aspect of the embodiment of the application realizes customization, can meet the performance requirements of different sides, and has two or more substructures and multi-aspect performance advantages.
In some embodimentsLithium manganese iron phosphate has the general formula: li (1+x) (Fe+Mn) y PO 4 /zC，0<x<0.02，0.95<y<1，0.5wt％<z<3wt%. Alternatively, x is 0.001, 0.005, 0.008, 0.01, 0.012, 0.015, 0.018, or 0.02. Alternatively, y is 0.96, 0.97, 0.98, or 0.99. Alternatively, z is 0.6wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, or 2.9wt%.
In some embodiments, the lithium manganese iron phosphate has the general formula: li (1+x) (Fe+Mn) y M p PO 4 /zC，0<x<0.02，0.95<y<1，0<p<0.01，0.5wt％<z<3wt%, wherein M represents a doping element. Alternatively, x is 0.001, 0.005, 0.008, 0.01, 0.012, 0.015, 0.018, or 0.02. Alternatively, y is 0.96, 0.97, 0.98, or 0.99. Alternatively, z is 0.6wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, or 2.9wt%. Alternatively, p is 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, or 0.01. Optionally, M comprises one or more doping elements of Mg, ca, co, ni, cu, zn, al, ga, sc, Y, la, ti, zr, V, nb, cr, mo.
A fifth aspect of embodiments of the present application provides an electrode comprising lithium manganese iron phosphate as provided in the fourth aspect of embodiments of the present application.
The electrode provided by the fifth aspect of the embodiment of the application has good performance and low cost.
A sixth aspect of embodiments of the present application provides a battery comprising an electrode as provided in the fifth aspect of embodiments of the present application.
The battery provided by the sixth aspect of the embodiment of the application has good performance and low cost.
The following description will be given with reference to specific examples.
Example 1
Weighing ferrous sulfate and manganese sulfate to prepare a ferrous sulfate and manganese sulfate mixed solution, mixing the ferrous sulfate and manganese sulfate mixed solution with an ammonium oxalate solution for precipitation, and filtering, washing and drying the obtained slurry to obtain a ferrous oxalate and manganese intermediate. Mixing the intermediate of the manganese ferrous oxalate, the lithium dihydrogen phosphate, the lithium carbonate, a carbon source, a dispersant, water and the like in a certain order,obtaining a mixture in which the ferro-manganese intermediate, the lithium source and the phosphorus source are Li according to the component molecular formula 1.015 (Fe+Mn) y0.98 PO 4 And (4) batching. And sanding the mixture until slurry with the granularity D50 of 500-600 nm is obtained. And (3) performing spray drying on the ground slurry to obtain lithium manganese iron phosphate precursor powder P0 with the water content of 3-5wt% and the particle size D50 of 10-20 mu m.
Mixing iron phosphate, manganese carbonate, lithium dihydrogen phosphate, lithium carbonate, a carbon source, a dispersing agent, water and the like in a certain sequence to obtain a mixture, wherein the iron source, the manganese source, the lithium source and the phosphorus source are mixed according to a component molecular formula Li 1.015 (Fe+Mn) y0.98 PO 4 And (4) batching. And sanding the mixture until slurry with the granularity D50 of 200nm-300nm is obtained. And (3) carrying out spray drying on the slurry after sanding to obtain lithium ferric manganese phosphate precursor powder P1 with the water content of 2-3wt% and the granularity D50 of 10-20 microns.
And mixing the two lithium manganese iron phosphate precursors P0 and P1, wherein P0 accounts for 70% and P1 accounts for 30% of the molar weight of (Fe + Mn), so as to obtain the lithium manganese iron phosphate precursor powder.
And roasting the lithium manganese phosphate precursor powder under the roasting condition of nitrogen atmosphere, the highest temperature of 700 ℃ and the heat preservation time of 3 hours, and cooling along with the furnace to obtain the lithium manganese phosphate roasted material. And (3) performing jet milling on the lithium manganese phosphate calcined material to obtain lithium manganese phosphate anode material powder.
The main indexes of the lithium manganese iron phosphate are as follows: primary particles with the particle size of 150nm-250nm and the specific surface area of 15m 2 The specific capacity of the carbon residue is 1.7wt%, the resistivity is 140 omega cm, the compacted density is 2.28g/cc, the charging specific capacity is 154.5mAh/g and the discharging specific capacity is 152.9mAh/g, and the charging capacity is 0.1C.
Example 2
Weighing ferrous sulfate and manganese sulfate to prepare a ferrous sulfate and manganese sulfate mixed solution, mixing the ferrous sulfate and manganese sulfate mixed solution with an ammonium oxalate solution for precipitation, and filtering, washing and drying the obtained slurry to obtain a ferrous oxalate and manganese intermediate. Mixing the intermediate of the ferrous manganese oxalate, ammonium dihydrogen phosphate, lithium carbonate, a carbon source, a dispersing agent, water and the like in a certain sequence, and adding ferric phosphate and manganese carbonate into the mixture, wherein the iron phosphate and the manganese carbonate contribute to (Fe + Mn) account forThe total mole amount of the product (Fe + Mn) is 20 percent, and a mixture is obtained, wherein the ferro-manganese intermediate, the lithium source and the phosphorus source are Li according to the component molecular formula 1.015 (Fe+Mn) y0.98 PO 4 And (4) batching. And (3) sanding the mixed material until slurry with the granularity D50 of 400nm-500nm is obtained. And (3) carrying out spray drying on the slurry after sanding to obtain lithium manganese iron phosphate precursor powder with the water content of 3-4wt% and the particle size D50 of 10-20 microns.
And roasting the lithium manganese iron phosphate precursor powder under the roasting conditions of nitrogen atmosphere, the highest temperature of 700 ℃ and the heat preservation time of 3 hours, and cooling along with the furnace to obtain the lithium manganese iron phosphate roasted material. And (3) carrying out air flow crushing on the lithium manganese iron phosphate calcined material to obtain lithium manganese iron phosphate anode material powder.
The main indexes of the lithium manganese iron phosphate are as follows: primary particle 100nm-150nm, specific surface area 18m 2 The specific capacity per gram, the residual carbon capacity is 1.8wt%, the resistivity is 310 omega cm, the compacted density is 2.21g/cc, the charging specific capacity per 0.1C is 154.3mAh/g, and the discharging specific capacity is 148.5mAh/g.
Example 3
Weighing ferrous sulfate and manganese sulfate to prepare a ferrous manganese sulfate mixed solution, mixing the ferrous manganese sulfate mixed solution with an ammonium dihydrogen phosphate and ammonia water mixed solution for precipitation, and filtering, washing, drying and roasting the obtained slurry to obtain a ferrous manganese phosphate intermediate. Mixing a ferrous manganese phosphate intermediate, lithium phosphate, a carbon source, a dispersing agent, water and the like in a certain order to obtain a mixture, wherein the ferrous manganese intermediate, the lithium source and the phosphorus source are Li according to the component molecular formula 1.015 (Fe+Mn) y0.98 PO 4 And (4) batching. Sanding the mixture until obtaining slurry with the granularity D50 of 200nm-300 nm; and at the moment, adding a ferrous manganese oxalate intermediate and a corresponding phosphorus source and a lithium source, wherein the (Fe + Mn) contributed by the ferrous manganese oxalate accounts for 20% of the total molar amount of the finished product (Fe + Mn), and continuing sanding until the granularity of the slurry presents a bimodal structure, wherein the bimodal D50 is 200-300 nm and 500-600 nm respectively. And (3) carrying out spray drying on the slurry after sanding to obtain lithium manganese iron phosphate precursor powder with the water content of 3-5wt% and the particle size D50 of 10-20 microns.
And roasting the lithium manganese iron phosphate precursor powder under the roasting conditions of nitrogen atmosphere, the highest temperature of 700 ℃ and the heat preservation time of 3 hours, and cooling along with the furnace to obtain the lithium manganese iron phosphate roasted material. And (3) performing jet milling on the lithium manganese phosphate calcined material to obtain lithium manganese phosphate anode material powder.
The main indexes of the obtained lithium manganese iron phosphate are as follows: primary particle 100-300 nm, specific surface area 14m 2 The specific charge capacity is 156.4mAh/g and the specific discharge capacity is 150.8mAh/g, wherein the residual carbon content is 1.5wt%, the resistivity is 260 omega cm, the compacted density is 2.33g/cc, the charging capacity is 0.1C, and the specific discharge capacity is 150.8mAh/g.
Example 4
Weighing ferrous sulfate and manganese sulfate to prepare a ferrous manganese sulfate mixed solution, adding a ferrous manganese oxalate intermediate into the mixed solution, wherein (Fe + Mn) contributed by the ferrous manganese oxalate accounts for 20% of the total mole amount of finished products (Fe + Mn), uniformly mixing, precipitating together with a mixed solution of ammonium dihydrogen phosphate and ammonia water, filtering, washing and drying the obtained slurry to obtain a composite manganese intermediate compounded with the ferrous manganese phosphate intermediate. Mixing the compound ferro-manganese intermediate, lithium phosphate, ammonium dihydrogen phosphate, lithium carbonate, a carbon source, a dispersing agent, water and the like in a certain sequence to obtain a mixture, wherein the compound ferro-manganese intermediate, the lithium source and the phosphorus source are mixed according to a component molecular formula Li 1.015 (Fe+Mn) y0.98 PO 4 And (4) batching. And sanding the mixture until slurry with the granularity D50 of 300nm-400nm is obtained. And (3) performing spray drying on the ground slurry to obtain lithium manganese iron phosphate precursor powder with the water content of 3-4.5wt% and the particle size D50 of 10-20 mu m.
And roasting the lithium manganese phosphate precursor powder under the roasting condition of nitrogen atmosphere, the highest temperature of 700 ℃ and the heat preservation time of 3 hours, and cooling along with the furnace to obtain the lithium manganese phosphate roasted material. And (3) carrying out air flow crushing on the lithium manganese iron phosphate calcined material to obtain lithium manganese iron phosphate anode material powder.
The main indexes of the obtained lithium manganese iron phosphate are as follows: primary particles of 200nm-300nm and specific surface area of 15m 2 The specific capacity per gram, the residual carbon capacity is 1.6wt%, the resistivity is 380 omega cm, the compacted density is 2.28g/cc, the charging specific capacity per 0.1C is 158.5mAh/g, and the discharging specific capacity is 155.2mAh/g.
Comparative example 1
Iron phosphate, manganese carbonate, lithium dihydrogen phosphate, lithium carbonate, a carbon source,Mixing a dispersing agent, water and the like in a certain sequence to obtain a mixture, wherein the iron source, the manganese source, the lithium source and the phosphorus source are in accordance with the component molecular formula Li 1.015 (Fe+Mn) y0.98 PO 4 And (4) batching. And (3) sanding the mixed material until slurry with the particle size D50 of 200nm-300nm is obtained. And (3) performing spray drying on the ground slurry to obtain lithium manganese iron phosphate precursor powder with the water content of 2-3wt% and the particle size D50 of 10-20 microns.
And roasting the precursor powder under the nitrogen atmosphere at the highest temperature of 700 ℃ for 3 hours, and cooling along with the furnace to obtain the lithium manganese iron phosphate roasted material. And (3) carrying out air flow crushing on the lithium manganese iron phosphate calcined material to obtain lithium manganese iron phosphate anode material powder.
The main indexes of the lithium manganese iron phosphate are as follows: primary particles 250nm-350nm and specific surface area 9m 2 The specific capacity of the carbon residue is 1.5wt%, the resistivity is 620 omega cm, the compacted density is 2.35g/cc, the charging specific capacity is 133.8mAh/g and the discharging specific capacity is 132.2mAh/g, and the charging capacity is 0.1C.
Comparative example 2
Weighing ferrous sulfate and manganese sulfate to prepare a ferrous sulfate and manganese sulfate mixed solution, mixing the ferrous sulfate and manganese sulfate mixed solution with an ammonium oxalate solution for precipitation, and filtering, washing and drying the obtained slurry to obtain a ferrous oxalate and manganese intermediate. Mixing a ferrous manganese oxalate intermediate, ammonium dihydrogen phosphate, lithium carbonate, a carbon source, a dispersing agent, water and the like in a certain sequence to obtain a mixture, wherein the ferrous manganese oxalate intermediate, the lithium source and the phosphorus source are in accordance with a component molecular formula Li 1.015 (Fe+Mn) y0.98 PO 4 And (4) batching. And (3) sanding the mixed material until slurry with the granularity D50 of 500nm-600nm is obtained. And (3) performing spray drying on the ground slurry to obtain lithium manganese iron phosphate precursor powder with the water content of 3-5wt% and the particle size D50 of 10-20 microns.
And roasting the precursor powder under the nitrogen atmosphere at the highest temperature of 700 ℃ for 3 hours, and cooling along with the furnace to obtain the lithium manganese iron phosphate roasted material. And (3) performing jet milling on the lithium manganese phosphate calcined material to obtain lithium manganese phosphate anode material powder.
The main indexes of the obtained lithium manganese iron phosphate are as follows: the primary particles are 50nm-100nm, the specific surface area is 24m < 2 >/g, the residual carbon content is 2.5wt%, the resistivity is 240 omega cm, the compacted density is 1.83g/cc, the charging specific capacity is 155.5mAh/g and the discharging specific capacity is 154.9mAh/g when the charging is 0.1C.
To verify the advancement of the examples of the present application, the following tests were performed on the samples prepared in the examples and comparative examples, respectively:
1. the morphologies of the lithium manganese iron phosphate prepared in example 1, comparative example 1, and comparative example 2 were observed, and as shown in the Scanning Electron Microscope (SEM) images of fig. 2 to 4, respectively, the particle size of the lithium manganese iron phosphate prepared in example 1 and comparative example 1 was larger than that of the lithium manganese iron phosphate prepared in comparative example 2.
2. The charging test is performed on the lithium manganese iron phosphate prepared in the example 1, the comparative example 1 and the comparative example 2, and as shown in the charging and discharging test results of fig. 5 to 7, which are 0.1C, the charging specific capacity and the discharging specific capacity of the lithium manganese iron phosphate prepared in the example 1 and the comparative example 2 are higher than those of the lithium manganese iron phosphate prepared in the comparative example 1.
3. The lithium manganese iron phosphate materials prepared in examples 1, 2, 3, and 4 and comparative examples 1 and 2 were subjected to performance tests, and the test results are shown in table 1 below.
TABLE 1 lithium manganese iron phosphate Performance test results
Figure BDA0003845898220000171
As can be seen from table 1, the lithium manganese iron phosphate prepared in comparative example 1, that is, the lithium manganese iron phosphate prepared by the one-step iron phosphate process has higher compacted density and lower residual carbon content, but has lower charge specific capacity and discharge specific capacity, small specific surface area, high resistivity, and relatively larger primary particle size; the lithium manganese phosphate prepared by the comparative example 2 is relatively small in compacted density and relatively high in residual carbon capacity, but is relatively high in charge specific capacity and discharge specific capacity, large in specific surface area, small in resistivity and relatively small in primary particle size.
Compared with the comparative example 1, the embodiment 1 adopts a two-step method for synthesizing lithium manganese iron phosphate by using a ferro-manganese grass process, 30% of the lithium manganese iron phosphate precursor prepared in the comparative example 1 is mixed and compounded after spray drying to obtain the lithium manganese iron phosphate precursor, and the precursor is roasted and crushed to obtain the lithium manganese iron phosphate. The composite process combines the advantages of comparative example 1 and comparative example 2. Compared with comparative example 1, the lithium manganese iron phosphate obtained in example 1 has smaller primary particles, the resistivity is reduced, the 0.1C discharge capacity is obviously improved, and the advantage of larger compaction density is retained. Compared with the comparative example 2, the lithium manganese iron phosphate obtained in the example 1 has the advantages of obviously reduced specific surface area, reduced residual carbon content and obviously improved compaction density. In this embodiment, the reaction precursors with different carbon formulations are added in the pretreatment step, so that the growth degree of different particles during roasting can be controlled, the particle size distribution matching between the particles easy to sinter and the particles difficult to sinter is regulated, a conductance fast channel is constructed, and the conductivity and the compaction density are balanced.
Compared with the comparative example 2, the example 2 has the advantages that the ferrophosphorus process raw materials are mixed in during material mixing, so that the sanding viscosity can be reduced, and the grinding efficiency is improved; the compacted density of the lithium manganese iron phosphate obtained by roasting and crushing the lithium manganese iron phosphate precursor is obviously improved, the specific surface area is reduced, and only 0.1C discharge is slightly reduced. In the embodiment, the reaction precursor is added in the step of mixing treatment, so that the mixing reaction can be influenced, and the physical properties of the sanding slurry can be regulated.
In the embodiment 3, a two-step ferrous manganese phosphate process is adopted, the raw materials of the ferrous manganese phosphate process are mixed in the later period of sanding, and the size of primary particles is in bimodal distribution. The lithium manganese iron phosphate obtained after roasting and crushing the precursor has wider particle size distribution and obvious bimodal structure, and the compacted density can reach 2.33g/cc after the large particles and the small particles are matched. In this example, the addition of reaction precursors having significantly different particle size distributions at the step of milling treatment allows for a gradation of primary particle size distribution, increasing the primary particle bulk density and, in turn, the compaction density.
In the embodiment 4, a two-step ferrous manganese phosphate process is adopted, the intermediate of the ferric manganese is added when the intermediate of the ferrous manganese phosphate is prepared, the intermediate of the ferric manganese with a loose outer layer and a compact inner layer can be formed, and the carbon source distribution in the precursor formed by mixing and spraying is wider and more uniform. The lithium ferric manganese phosphate obtained by roasting and crushing the precursor has good compaction density and electrical property. In this embodiment, reaction precursors with different element distribution states are added in the step of preparing the ferromanganese intermediate, so that the composition of an element uniform distribution phase and an element non-uniform distribution phase can be realized, and the coating or other forms of accumulation regulation of the ferromanganese intermediate on the reaction precursors can be performed.
According to the embodiment of the application, different reaction precursor composition is carried out in different processes of synthesizing the lithium ferric manganese phosphate by the two-step method, so that the lithium ferric manganese phosphate precursors with different characteristics are compounded in different layers. Based on different purposes, on the aspects of uniform element distribution, crystal coating, primary particle mixing, secondary particle mixing and the like, the composition of the lithium manganese iron phosphate precursor can be implemented in different processes of the process, different composite effects can be realized, different lithium manganese iron phosphate precursors can be obtained, and then different physicochemical characteristics of different lithium manganese iron phosphate precursors can be utilized to enable the precursors to present new characteristics during roasting, so that the lithium manganese iron phosphate anode material with adjustable and controllable primary particle size morphology, particle size distribution and carbon coating can be obtained.
The above description is only a preferred embodiment of the present application and should not be taken as limiting the present application, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (14)

1. A preparation method of a lithium ferric manganese phosphate precursor is characterized by comprising the following steps:
preparing a ferro-manganese intermediate: providing a first iron source and a first manganese source, and preparing a first ferro-manganese intermediate;
mixing treatment: mixing the first iron-manganese intermediate, the first phosphorus source, the first lithium source and the first carbon source to obtain a mixture;
grinding treatment: grinding the mixture;
the pretreatment step comprises: pretreating the ground mixture to obtain a lithium manganese iron phosphate precursor;
the preparation method of the lithium ferric manganese phosphate precursor further comprises the following steps:
providing a reaction precursor for preparing a lithium ferric manganese phosphate precursor, and adding the reaction precursor and performing corresponding treatment in at least one of the steps of preparing a ferric manganese phosphate intermediate, the mixing treatment, the grinding treatment and the pretreatment.
2. The method for preparing a lithium ferric manganese phosphate precursor according to claim 1, wherein said reaction precursor is added in said step of preparing a ferro-manganese intermediate, said step of preparing a ferro-manganese intermediate comprising: providing a first iron source and a first manganese source; mixing the first iron source, the first manganese source and the reaction precursor to prepare a mixed precipitate containing a first ferro-manganese intermediate and the reaction precursor; wherein the reaction precursor comprises a second ferro-manganese intermediate;
and in the step of mixing material, mixing the mixed precipitate, the first phosphorus source, the first lithium source and the first carbon source to obtain a mixed material.
3. The method of preparing a lithium ferric manganese phosphate precursor of claim 2, wherein the first iron source comprises a ferrous sulfate solution, the first manganese source comprises a manganese sulfate solution, and the second ferric manganese intermediate comprises a ferrous iron oxalate intermediate.
4. The method for preparing a lithium manganese iron phosphate precursor according to claim 1, wherein said reaction precursor is added in said step of mixing, and said step of mixing treatment comprises: mixing the first iron-manganese intermediate, the first phosphorus source, the first lithium source, the first carbon source and the reaction precursor to obtain a mixture; wherein the reaction precursor comprises a second iron source, a second manganese source, a second phosphorus source, a second lithium source, and a second carbon source.
5. The method for preparing a lithium manganese iron phosphate precursor according to claim 1, wherein said reactive precursor is added at the step of said milling treatment, which comprises: grinding the mixture, adding the reaction precursor into the mixture, and continuing to carry out grinding treatment; wherein the reaction precursor comprises a third phosphorus source, a third lithium source, a third carbon source and a third ferrimanganic intermediate.
6. The method for preparing the lithium ferric manganese phosphate precursor according to claim 5, wherein the first intermediate is a manganese ferrous phosphate intermediate and the third intermediate is a manganese ferrous oxalate intermediate.
7. The method for preparing a lithium manganese iron phosphate precursor according to claim 1, wherein said reaction precursor is added in said step of pre-treating, said step of pre-treating comprising: preprocessing the mixture to obtain a first lithium manganese iron phosphate precursor, and mixing the first lithium manganese iron phosphate precursor with the reaction precursor to obtain a lithium manganese iron phosphate precursor; wherein the reaction precursor comprises a second lithium ferric manganese phosphate precursor.
8. The method of preparing the lithium ferric manganese phosphate precursor of claim 7, wherein preparing the second lithium ferric manganese phosphate precursor comprises: and mixing, grinding and drying a fourth iron source, a fourth manganese source, a fourth phosphorus source, a fourth lithium source and a fourth carbon source to obtain the second lithium manganese iron phosphate precursor.
9. A lithium manganese iron phosphate precursor, characterized in that the lithium manganese iron phosphate precursor is prepared according to the method of any one of claims 1 to 8.
10. A preparation method of lithium iron manganese phosphate is characterized by comprising the following steps: the lithium manganese iron phosphate precursor according to claim 9 is calcined to obtain lithium manganese iron phosphate.
11. A lithium manganese phosphate prepared according to the method of claim 10.
12. The lithium manganese iron phosphate of claim 11, wherein said lithium manganese iron phosphate has the formula: li (1+x) (Fe+Mn) y PO 4 /zC，0<x<0.02，0.95<y<1，0.5wt％<z<3wt%; or the lithium ferric manganese phosphate has the following general formula: li (1+x) (Fe+Mn) y M p PO 4 /zC，0<x<0.02，0.95<y<1，0<p<0.01，0.5wt％<z<3wt%, wherein M represents a doping element.
13. An electrode comprising the lithium manganese iron phosphate according to any one of claims 11 to 12.
14. A battery comprising the electrode of claim 13.
CN202211116752.5A 2022-09-14 2022-09-14 Lithium manganese iron phosphate precursor, lithium manganese iron phosphate, preparation methods of lithium manganese iron phosphate precursor and lithium manganese iron phosphate, electrode and battery Pending CN115611254A (en)

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