CN108511700A - Mostly metal-doped lithium iron phosphate/carbon composite material and preparation method - Google Patents

Mostly metal-doped lithium iron phosphate/carbon composite material and preparation method Download PDF

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CN108511700A
CN108511700A CN201810062087.3A CN201810062087A CN108511700A CN 108511700 A CN108511700 A CN 108511700A CN 201810062087 A CN201810062087 A CN 201810062087A CN 108511700 A CN108511700 A CN 108511700A
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metal
doped
iron
phosphate
carbon composite
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CN108511700B (en
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张云
吴昊
曾金明
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Sichuan University
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Sichuan University
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    • 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
    • H01M4/362—Composites
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light 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
    • 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
    • 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 present invention relates to how metal-doped lithium iron phosphate/carbon composite material and preparation method, how metal-doped lithium iron phosphate/carbon composite material, molecular formula is LiFe(1‑(a/2)x‑(b/2)y)MxNyPO4/ C, wherein x+y=0.01 0.1, M, N are doping metals, and a, b are respectively the valence state of M, N doping metals, and a, b are not 0, and a is divalent hereinafter, b is trivalent or more；Wherein, doping metals M, N occupies iron position in situ.The how metal-doped lithium iron phosphate/carbon composite material of the present invention and preparation method, when it can evade ferrous valence transition into ferric iron valence state, certain doping metals can be extruded from the former iron position occupied and cannot be introduced into LiFePO4 or cell positive material, weaken the performance issue of gained cell positive material.Also can get simultaneously can directly adulterate the above metal of trivalent and the not directly lithium iron phosphate/carbon composite material of the various metals mixing and doping of the doping following metal of divalent.

Description

Mostly metal-doped lithium iron phosphate/carbon composite material and preparation method
Technical field
The present invention relates to how metal-doped lithium iron phosphate/carbon composite material and preparation methods.
Background technology
Lithium iron phosphate electrode material since it has extended cycle life, the advantages that security performance is high and good thermal stability to Great application prospect.But since its own structure limits, PO4Tetrahedron is located at FeO6Between layer, to Li+Diffusion is hindered, And Li+Diffusion admittance is single；PO simultaneously4Tetrahedral oxygen atom separates, FeO6For total vertex connect, cause electron conductivity compared with It is low, cause the application of lithium iron phosphate electrode material to be restricted.
Currently, the mode being modified to LiFePO4 is centered around nanosizing, cladding and metal ion or metal oxide is mixed Miscellaneous mode carries out.Nanosizing is to make to change to bulk of molecule, state；Cladding is in substance macroscopic aspect or molecular layer bread Wrap up in one layer of particular matter；Doping is then between particle, intermolecular or intramolecular ion or oxide are compound.
Wherein, metal ion mixing can effectively widen lithium ion transport path, while improve electron conductivity, by people Concern.The type and mode of doping are varied, and academic circles at present studies not perfect, example for the theoretical mechanism of doping Such as during the metal ion mixing of LiFePO4, it is also difficult to which it is to occupy Li or Fe to control doped metal ion, is led to It is often to be controlled by technique.Simple physical mixed, although metal ion is incorporated into material to a certain extent, It is that the uniformity of particle cannot be guaranteed, while can only realizes and adulterate between particle.The ferric phosphate of current such as metal ion mixing The preparation method of lithium is typically to use two ways, and one is ferrous phosphates and doping metals to be melted by suspension or solid powder The ferrous phosphate that reaction obtains doping is closed, the ferrous phosphate of doping metals is then subjected to the phosphoric acid that oxidation obtains doping metals again Iron (ferric iron), finally synthesizing iron lithium phosphate positive electrode again；Another kind is ferric phosphate directly and doping metals carry out suspension Or solid powder fusion reaction, the ferric phosphate (ferric iron) or LiFePO4 (ferric iron) of doping metals are obtained, is finally restored. (be not known in text and illustrate that the expression iron of trivalent valence state is divalent state)
Invention content
But it is practical in two kinds of preparation methods above-mentioned, test is carried out to the ferric phosphate or LiFePO4 that are obtained and is learnt, Certain metal ions (such as Mg, Co, Zn, Ni, Ca, Sr or Cu) for being doped into ferric phosphate or LiFePO4 simultaneously not all occupy Former iron position, namely it is not carried out the purpose that doped metal ion intramolecular occupies iron position.In aforementioned preparation process, although the first The ferrous phosphate in former iron position metal ion mixing is obtained, but during subsequent oxidation, due to LiFePO4 knot above-mentioned Structure limits, and certain doping metals cannot be introduced into ferric phosphate or LiFePO4；Second method ferric phosphate is directly and doping is golden Belong to reaction, realizes that doping intramolecular occupies the effect of iron position in situ also without by doped metal ion.The phosphorus obtained in this way Sour iron lithium and corresponding cell positive material are weakened in the performances such as charge and discharge.
A kind of how metal-doped lithium iron phosphate/carbon composite material of present invention offer and preparation method, can evade ferrous iron When valence transition is at ferric iron valence state, certain doping metals can be extruded from the former iron position occupied and cannot be introduced into LiFePO4 or In cell positive material, weaken the performance issue of gained cell positive material.It also can get simultaneously and directly adulterate trivalent or more gold Belong to (such as Al, Ti, V, Mn or Ce) and not directly adulterates the following metal of divalent (such as Mg, Co, Zn, Ni, Ca, Sr or Cu) The lithium iron phosphate/carbon composite material of various metals mixing and doping.
In order to solve the above technical problems, the present invention provides the technical solution of first aspect, i.e., a kind of how metal-doped phosphoric acid Iron lithium/carbon composite material, molecular formula are LiFe(1-(a/2)x-(b/2)y)MxNyPO4/ C, wherein x+y=0.01-0.1, M, N are doping Metal, a, b are respectively the valence state of M, N doping metals, and a, b are not 0, and a is divalent hereinafter, b is trivalent or more；Wherein, it mixes Miscellaneous metal M, N occupy iron position in situ.
Preferably, the metal M is the one of which in Mg, Co, Zn, Ni, Ca, Sr or Cu, and N is Al, Ti, V, Mn or Ce In one of which.
Preferably, y≤x.
Preferably, y≤(x/2).
The application also provides the technical solution of second aspect, i.e., the preparation of how metal-doped lithium iron phosphate/carbon composite material Method includes the following steps,
1) the metal-doped hypophosphite monohydrate ferrous irons of M and the metal-doped hypophosphite monohydrate iron of N, molecular formula point are prepared respectively It is not [Fe(1-(a/2)x)Mx]3(PO4)2·mH2O and Fe(1-(b/3)y)NyPO4·nH2O；
2) by a certain percentage by the metal-doped hypophosphite monohydrate iron of metal-doped M 1) obtained hypophosphite monohydrate ferrous iron and N After mixing, and is calcined in a nitrogen atmosphere with phosphorus source, lithium source and carbon source and obtain how metal-doped lithium iron phosphate/carbon composite material.
Preferably, the metal-doped hypophosphite monohydrate iron of hypophosphite monohydrate ferrous iron and the N metal-doped step 1) obtains M Within the temperature range of 60 DEG C -500 DEG C, the lower heat preservation of nitrogen atmosphere protection obtains the metal-doped hypophosphite monohydrates of partially dehydrated M Ferrous or metal-doped N anhydrous iron phosphate, and it is used for step 2).
Preferably, the lower soaking time of nitrogen atmosphere protection is 0.5-3h in step 1).
Preferably, it includes step in detail below that the metal-doped hypophosphite monohydrate ferrous irons of M, which are prepared, in step 1), will be soluble 20-80 minutes phosphate solution used time was at the uniform velocity added to element ratio Fe respectively：M=(1-x)：X, the iron of (x=0.01-0.1) With metal M mixed salt solutions, the total concentration of metal ions of this mixed solution is 0.1-2.0M in source；This mixed solution is stirred, simultaneously Aqueous slkali is added dropwise and adjusts pH to 5.0-7.5；Continue to stir after the completion of charging, being filtered, washed rear low temperature drying, to obtain M metal-doped Hypophosphite monohydrate it is ferrous.
Preferably, it includes step in detail below that the metal-doped hypophosphite monohydrate iron of N, which is prepared, in step 1), by titanium pigment 20-80 minutes acid salt solution used time was at the uniform velocity added to element ratio Fe respectively：N=(1-y)：The source of iron of y (y=0.01-0.1) with In metal N mixed salt solutions, the total concentration of metal ions of this mixed solution is 0.1-2.0M；This mixed solution is stirred, oxidation is added dropwise Agent, oxidant excess 20%-100%, while aqueous slkali is added dropwise and adjusts pH to 5.0-7.5；Continue to stir after the completion of charging, mistake Low temperature drying obtains the metal-doped hypophosphite monohydrate iron of N after filter, washing.
Preferably, the molar concentration of soluble phosphoric acid salting liquid is 0.1-2.0M in step 1).
Preferably, the mass fraction concentration of aqueous slkali is 5-50wt% in step 1).
Preferably, it is 0-240min to continue mixing time in step 1) after the completion of charging.
Preferably, the volume of soluble phosphate and the volume ratio of mixed solution are (1.5-2.5) in step 1)：3.
Preferably, oxidant described in step 1) is hydrogen peroxide or oxygen.
Preferably, oxidant is at the uniform velocity added dropwise in used time 20-200min in step 1).
Preferably, step 2) is as follows, metal-doped the M that step 1) is obtained hypophosphite monohydrate ferrous iron and N After metal-doped hypophosphite monohydrate iron is mixed in a certain ratio, and first it is sanded with phosphorus source, lithium source and carbon source, through drying, then Calcining obtains how metal-doped lithium iron phosphate/carbon composite material in a nitrogen atmosphere.
Preferably, it is 0.15-0.8 μm to be sanded in step 2) to fineness.
Preferably, mode dry in step 2) is spray drying.
M is to be unable to metal such as Mg, Zn, Ca, Sr or Cu that ferric iron directly adulterates, or be difficult to three in the application The metal that valence iron directly adulterates such as Co or Ni, it is divalent or the metal less than divalent that these metals, which substantially belong to doping valence state, That is the above metal of divalent；In the application N be can ferric iron metal such as Ti, Al, V or Mn for directly adulterating, these Metal Substrates Originally it is trivalent or the metal higher than trivalent, the i.e. above metal of trivalent to belong to doping valence state.
The application is by way of improving LiFePO4 doped metal ion, synthesis iron position original position metal ion mixing hydration The lag of ferrous phosphate, lithium source introduces, it is ensured that doped metal ion will not preferentially occupy Li；Meanwhile it can evade and prepare phosphorus When ferrous valence transition is at ferric iron valence state during sour iron, certain doping metals can be extruded from the former iron position occupied and be formed Doping metals atom is mixed into LiFePO4 or cell positive material, weakens the performance issue of gained cell positive material.
Description of the drawings
Fig. 1 is the LiFe of the embodiment of the present invention 30.98Mg0.01V0.02PO4The XRD spectra of/C；
Fig. 2 is the LiFe of the embodiment of the present invention 40.97Mg0.04Ti0.02PO4The high rate performance of/C positive electrode material.
Fig. 3 is the LiFe of the embodiment of the present invention 100.95Co0.02Ti0.03PO4The 1C discharge cycle performance figures of/C positive electrode material；
Fig. 4 is the LiFe of the embodiment of the present invention 130.97Zn0.01Ce0.02PO4The 10C discharge cycle performances of/C positive electrode material Figure；
Fig. 5 is the LiFe of the embodiment of the present invention 190.94Ni0.04Ti0.02PO4The SEM of/C positive electrode material schemes.
Specific implementation mode
To make the objectives, technical solutions, and advantages of the present invention clearer, below in conjunction with embodiment of the present invention In attached drawing, the technical solution in embodiment of the present invention is clearly and completely described, it is clear that described embodiment party Formula is only some embodiments of the invention, rather than whole embodiments.Based on the embodiment in the present invention, ability The every other embodiment that domain those of ordinary skill is obtained without making creative work, belongs to the present invention The range of protection.In the absence of conflict, the feature in the embodiment and embodiment in the present invention can be mutually arbitrary Combination.
The eight hypophosphite monohydrate ferrous irons and Iron phosphate (FePO4) dihydrate adulterated with different metal ions in the application synthesize more metals and mix Miscellaneous lithium iron phosphate/carbon composite material, before being introduced due to lithium source, doped metal ion is formd with ferrous ion or iron ion The product of ionic level mixing, it is ensured that doped metal ion preferentially occupies iron position in situ；Meanwhile it being easy in preparation process Be extruded it is metal-doped in, not by ferrous oxidation at ferric iron, effectively prevent ferrous phosphate and generate ferric phosphate this mistake Journey, dissolving oxidation recrystallization will not occur for ferrous phosphate, therefore will not occur to cause doping metals because ferrous phosphate dissolves The phenomenon that ion is segregated, it is ensured that doped chemical is uniformly distributed；
In addition, in the application partially crystallizable water ferrous to metal-doped hypophosphite monohydrate or hypophosphite monohydrate iron removal, It can ensure be decomposed because of high temperature while its is not oxidized, more effectively ensure that doped metal ion will not It is extruded and is transformed into doping metals atom and is mixed into dewatered ferrous phosphate, ferric phosphate, LiFePO4 or cell positive material The case where；The removal of partially crystallizable water avoids generating a large amount of steam in follow-up sintering technique, reduces and synthesizes more metals under high temperature Side reaction is generated during doped iron lithium phosphate/carbon composite leads to the possibility that doping metals can not adulterate, it is ensured that most The chemical property of final product；
It is the how metal-doped lithium iron phosphate/carbon composite material obtained using preparation method described herein below, and And as every embodiment of cell positive material.
Embodiment one
1) the 20-80 minutes soluble phosphoric acid salting liquid used time that molar concentration is a1 is at the uniform velocity added to element ratio Fe:M =(1-x):For the source of iron of x with metal M mixed salt solutions, the total metal ion molar concentration of this mixed solution is 0.1-2.0M；It stirs This mixed solution is mixed, while the aqueous slkali that a concentration of b1 of mass fraction is added dropwise adjusts pH to 5.0-7.5；Continue to stir after the completion of charging It mixes, mixing time c, is filtered, washed rear low temperature drying and obtains the metal-doped hypophosphite monohydrate ferrous irons of M, molecular formula is [Fe(1-(a/2)x)Mx]3(PO4)2·mH2O, a are the valence state of M doping metals, and a is divalent or less；The volume of soluble phosphate with The volume ratio of mixed solution is d；
2) the 20-80 minutes soluble phosphoric acid salting liquid used time that molar concentration is a1 is at the uniform velocity added to element ratio Fe:N =(1-y):For the source of iron of y with metal N mixed salt solutions, the total metal ion molar concentration of this mixed solution is 0.1-2.0M；It stirs This mixed solution is mixed, while the aqueous slkali that a concentration of b1 of mass fraction is added dropwise adjusts pH to 5.0-7.5, oxidant, oxidation is added dropwise Agent excess 20%-100%；Continue to stir after the completion of charging, mixing time c is filtered, washed rear low temperature drying and obtains N metals The hypophosphite monohydrate iron of doping, molecular formula are Fe(1-(b/3)y)NyPO4·nH2O, b are the valence state of N doping metals, and b is trivalent or more； The volume of soluble phosphate and the volume ratio of mixed solution are d；
3) the hypophosphite monohydrate iron that the hypophosphite monohydrate metal-doped M that obtains step 1) and step 2) is ferrous, N is metal-doped It is e to be first sanded after being mixed with phosphorus source, lithium source and carbon source to fineness, spray-dried, then calcining obtains in a nitrogen atmosphere Mostly metal-doped lithium iron phosphate/carbon composite material；The molecular formula of mostly metal-doped lithium iron phosphate/carbon composite material is LiFe(1-(a/2)x-(b/2)y)MxNyPO4/ C, wherein x+y=0.01-0.1, M, N are doping metals, and a, b are respectively M, N doping metals Valence state, and a is divalent hereinafter, b is trivalent or more；Doping metals M, N occupy Fe in situ.
Source of iron described in step 1) can choose sulfate, nitrate, oxalates and the chlorination of iron in the above embodiment The solubility ferrous source such as salt, source of iron described in step 2) can choose sulfate, nitrate, oxalates and chlorate of iron etc. three Valence source of iron.
In the above embodiment soluble phosphate described in step 1) or step 2) can choose phosphoric acid, sodium phosphate or Any one in ammonium phosphate salt.
Step 1) metal M salt can choose the sulfate of Mg, Co, Zn, Ni, Ca, Sr or Cu, nitric acid in the above embodiment One kind in the soluble metallic salts such as salt and chlorate, N salt can choose the sulfate of Al, Ti, V, Mn or Ce, nitre in step 2) One kind in the soluble metallic salts such as hydrochlorate and chlorate.
Lithium source can choose lithium hydroxide, lithium carbonate, lithium nitrate, lithium phosphate or acetic acid in step 2) in the above embodiment One kind in lithium is used cooperatively with several, and dosage is molar ratio Li:Fe=1.03-1.06.
Phosphorus source described in step 2) can choose phosphoric acid, lithium phosphate or ammonium phosphate salt in the above embodiment, and dosage is In step 1) or step 2) in source of iron iron mole 1/3.
Carbon source can be chosen in glucose, sucrose, citric acid, vitamin C, starch in step 3) in the above embodiment One or more are used cooperatively, and addition accounts for the 10-20% of how metal-doped LiFePO4 quality.
Calcination temperature described in step 3) is 600 DEG C in the above embodiment, and heating rate is in 2-5 DEG C/min.
According to above-mentioned steps, different every preparation parameters is respectively adopted and is prepared, the preparation parameter of each embodiment is such as Shown in the following table 1；Preparation-obtained how metal-doped lithium iron phosphate/carbon composite material is subjected to coherent detection, such as doping gold The sum of the mole for belonging to M, N atom occupies the percentage l/% of the sum of mole of whole doping metals M, N, and gained is electric accordingly The first discharge specific capacity Q1/mAhg of pond positive electrode-1, 200 specific discharge capacity Q2/mAhg are recycled under 1C-1、10C The specific discharge capacity Q3/mAhg that lower cycle is 100 times-1Deng；Acquired results see the table below 2.
Table 1
Table 2
Embodiment l Q1 Q2 Q3
1 0 160 145 110
2 0 165 150 120
3 0 150 132 106
4 0 168 146 112
5 0 152 136 110
6 0 166 150 133
7 0 165 150 132
8 0 162 141 123
9 0 170 152 135
10 0 160 145 126
11 0 160 134 126
12 0 162 135 125
13 0 154 130 120
14 0 165 142 134
15 0 150 129 121
16 0 161 129 115
17 0 162 131 116
18 0 155 125 110
19 0 165 132 121
20 0 154 128 112
Embodiment two
1) the 20-80 minutes soluble phosphoric acid salting liquid used time that molar concentration is a1 is at the uniform velocity added to element ratio Fe:M =(1-x):For the source of iron of x with metal M mixed salt solutions, the total metal ion molar concentration of this mixed solution is 0.1-2.0M；It stirs This mixed solution is mixed, while the aqueous slkali that a concentration of b1 of mass fraction is added dropwise adjusts pH to 5.0-7.5；Continue to stir after the completion of charging It mixes, mixing time c, is filtered, washed rear low temperature drying and obtains the metal-doped eight hypophosphite monohydrates ferrous irons of M, molecular formula is [Fe(1-(a/2)x)Mx]3(PO4)2·8H2O, a are the valence state of M doping metals, and a is divalent or less；The volume of soluble phosphate with The volume ratio of mixed solution is d；Hypophosphite monohydrate ferrous iron metal-doped obtained M is within the temperature range of 60 DEG C -500 DEG C, nitrogen Atmosphere encloses the lower heat preservation 0.5-3h of protection, and it is ferrous to obtain the metal-doped hypophosphite monohydrates of partially dehydrated M；
2) the 20-80 minutes soluble phosphoric acid salting liquid used time that molar concentration is a1 is at the uniform velocity added to element ratio Fe:N =(1-y):For the source of iron of y with metal N mixed salt solutions, the total metal ion molar concentration of this mixed solution is 0.1-2.0M；It stirs This mixed solution is mixed, while the aqueous slkali that a concentration of b1 of mass fraction is added dropwise adjusts pH to 5.0-7.5, the used time, 20-200min was even Oxidant, oxidant excess 20%-100% is added dropwise in speed；Continue to stir after the completion of charging, mixing time c, after being filtered, washed Low temperature drying obtains the metal-doped hypophosphite monohydrate iron of N, and molecular formula is Fe(1-(b/3)y)NyPO4·2H2O, b are N doping metals Valence state, b are trivalents or more；The volume of soluble phosphate and the volume ratio of mixed solution are d；Water metal-doped obtained N Ferric phosphate is closed within the temperature range of 60 DEG C -500 DEG C, nitrogen atmosphere protection is lower to keep the temperature 0.5-3h, obtains metal-doped anhydrous of N Ferric phosphate；
3) the hypophosphite monohydrate metal-doped partially dehydrated M that obtains step 1) and step 2) is ferrous, N is metal-doped It is e that anhydrous iron phosphate, which is first sanded after being mixed with phosphorus source, lithium source and carbon source to fineness, spray-dried, then in nitrogen atmosphere Lower calcining obtains how metal-doped lithium iron phosphate/carbon composite material；The molecular formula of mostly metal-doped lithium iron phosphate/carbon composite material It is LiFe(1-(a/2)x-(b/2)y)MxNyPO4/ C, wherein x+y=0.01-0.1, M, N are doping metals, and a, b are respectively M, N doping gold The valence state of category, and a is divalent hereinafter, b is trivalent or more；Doping metals M, N occupy Fe in situ.
Source of iron described in step 1) can choose sulfate, nitrate, oxalates and the chlorination of iron in the above embodiment The solubility ferrous source such as salt, source of iron described in step 2) can choose sulfate, nitrate, oxalates and chlorate of iron etc. three Valence source of iron.
In the above embodiment soluble phosphate described in step 1) or step 2) can choose phosphoric acid, sodium phosphate or Any one in ammonium phosphate salt.
Step 1) metal M salt can choose the sulfate of Mg, Co, Zn, Ni, Ca, Sr or Cu, nitric acid in the above embodiment One kind in the soluble metallic salts such as salt and chlorate, N salt can choose the sulfate of Al, Ti, V, Mn or Ce, nitre in step 2) One kind in the soluble metallic salts such as hydrochlorate and chlorate.
Lithium source can choose lithium hydroxide, lithium carbonate, lithium nitrate, lithium phosphate or acetic acid in step 3) in the above embodiment One kind in lithium is used cooperatively with several, and dosage is molar ratio Li:Fe=1.03-1.06.
Phosphorus source described in step 3) can choose phosphoric acid, lithium phosphate or ammonium phosphate salt in the above embodiment, and dosage is In step 1) or step 2) in source of iron iron mole 1/3.
Carbon source can be chosen in glucose, sucrose, citric acid, vitamin C, starch in step 3) in the above embodiment One or more are used cooperatively, and addition accounts for the 10-20% of metal-doped LiFePO4 quality.
Calcination temperature described in step 3) is 600 DEG C in the above embodiment, and heating rate is in 2-5 DEG C/min.
According to above-mentioned steps, different every preparation parameters is respectively adopted and is prepared, the preparation parameter of each embodiment is such as Shown in the following table 3；Preparation-obtained how metal-doped lithium iron phosphate/carbon composite material is subjected to coherent detection, such as doping gold The sum of the mole for belonging to M, N atom occupies the percentage l/% of the sum of mole of whole doping metals M, N, and gained is electric accordingly The first discharge specific capacity Q1/mAhg of pond positive electrode-1, 200 specific discharge capacity Q2/mAhg are recycled under 1C-1、10C The specific discharge capacity Q3/mAhg that lower cycle is 100 times-1Deng；Acquired results see the table below 4.
Table 3
Table 4
It in upper table 2 and upper table 4, can be apparent from, the doping ratio of M, N metal is largely for specific discharge capacity Influence it is higher, such as in embodiment 1-5, embodiment 1-2, embodiment 4 specific discharge capacity be higher than embodiment 3,5, wherein Again with the specific discharge capacity higher of embodiment 4, remaining is similar.In addition the preparation method of table 3 and the preparation method of table 1 prepare gained How metal-doped lithium iron phosphate/carbon composite material in doping metals be it is in situ occupy iron position, but under different preparation methods The specific discharge capacity of the how metal-doped lithium iron phosphate/carbon composite material of table 4 in each condition is being apparently higher than the battery of table 2 just Pole material.As shown in attached drawing 1-5, the how metal-doped lithium iron phosphate/carbon composite material of the application acquisition can be characterized very well Various features, Fig. 1 be the embodiment of the present invention 3 LiFe0.98Mg0.01V0.02PO4The XRD spectra of/C；Fig. 2 is that the present invention is implemented The LiFe of example 40.97Mg0.04Ti0.02PO4The high rate performance of/C positive electrode material；Fig. 3 is the embodiment of the present invention 10 LiFe0.95Co0.02Ti0.03PO4The 1C discharge cycle performance figures of/C positive electrode material；Fig. 4 is the embodiment of the present invention 13 LiFe0.97Zn0.01Ce0.02PO4The 10C discharge cycle performance figures of/C positive electrode material；Fig. 5 is the embodiment of the present invention 19 LiFe0.94Ni0.04Ti0.02PO4The SEM of/C positive electrode material schemes.
It the above is only the preferred embodiment of the present invention, it is noted that above-mentioned preferred embodiment is not construed as pair The limitation of the present invention, protection scope of the present invention should be subject to claim limited range.For the art For those of ordinary skill, without departing from the spirit and scope of the present invention, several improvements and modifications can also be made, these change Protection scope of the present invention is also should be regarded as into retouching.

Claims (10)

  1. Metal-doped lithium iron phosphate/carbon composite material more than 1., it is characterised in that：Molecular formula is LiFe(1-(a/2)x-(b/2)y)MxNyPO4/ C, wherein x+y=0.01-0.1, M, N are doping metals, and a, b are respectively the valence state of M, N doping metals, and a, b are not 0, and a It is divalent hereinafter, b is trivalent or more；Wherein, doping metals M, N occupies iron position in situ.
  2. 2. how metal-doped lithium iron phosphate/carbon composite material according to claim 1, it is characterised in that：The metal M is One of which in Mg, Co, Zn, Ni, Ca, Sr or Cu, N are the one of which in Al, Ti, V, Mn or Ce.
  3. 3. how metal-doped lithium iron phosphate/carbon composite material according to claim 1, it is characterised in that：y≤x.
  4. 4. weighing the preparation method of the 1 how metal-doped lithium iron phosphate/carbon composite material, it is characterised in that：Include the following steps,
    1) the metal-doped hypophosphite monohydrate ferrous irons of M and the metal-doped hypophosphite monohydrate iron of N are prepared respectively, molecular formula is respectively [Fe(1-(a/2)x)Mx]3(PO4)2·mH2O and Fe(1-(b/3)y)NyPO4·nH2O；
    2) 1) the metal-doped hypophosphite monohydrate iron of metal-doped M obtained hypophosphite monohydrate ferrous iron and N is mixed in a certain ratio Afterwards, it and is calcined in a nitrogen atmosphere with phosphorus source, lithium source and carbon source and obtains how metal-doped lithium iron phosphate/carbon composite material.
  5. 5. preparation method according to claim 4, it is characterised in that：Hydration metal-doped M that the step 1) obtains Within the temperature range of 60 DEG C -500 DEG C, the lower heat preservation of nitrogen atmosphere protection obtains for ferrous phosphate and the metal-doped hypophosphite monohydrate iron of N The anhydrous iron phosphate that the hypophosphite monohydrate metal-doped to partially dehydrated M is ferrous or N is metal-doped, and it is used for step 2).
  6. 6. preparation method according to claim 4, it is characterised in that：The metal-doped hydration phosphorus of M is prepared in step 1) It is sour ferrous including step in detail below, the soluble phosphoric acid salting liquid used time is at the uniform velocity added to element ratio in 20-80 minutes respectively Fe：M=(1-x)：X, the source of iron of (x=0.01-0.1) in metal M mixed salt solutions, the total concentration of metal ions of this mixed solution For 0.1-2.0M；This mixed solution is stirred, while aqueous slkali is added dropwise and adjusts pH to 5.0-7.5；Continue to stir after the completion of charging, mistake It is ferrous to obtain the metal-doped hypophosphite monohydrates of M for low temperature drying after filter, washing.
  7. 7. preparation method according to claim 4, it is characterised in that：The metal-doped hydration phosphorus of N is prepared in step 1) Sour iron includes step in detail below, and the soluble phosphoric acid salting liquid used time is at the uniform velocity added to element ratio Fe in 20-80 minutes respectively： N=(1-y)：With metal N mixed salt solutions, the total concentration of metal ions of this mixed solution is the source of iron of y (y=0.01-0.1) 0.1-2.0M；This mixed solution is stirred, oxidant, oxidant excess 20%-100% is added dropwise, while aqueous slkali is added dropwise and adjusts pH To 5.0-7.5；Continue to stir after the completion of charging, is filtered, washed rear low temperature drying and obtains the metal-doped hypophosphite monohydrate iron of N.
  8. 8. according to any preparation method of claim 5 or 6, it is characterised in that：Soluble phosphoric acid salting liquid in step 1) Molar concentration be 0.1-2.0M.
  9. 9. according to any preparation method of claim 5 or 6, it is characterised in that：The body of soluble phosphate in step 1) Product and the volume ratio of mixed solution are (1.5-2.5)：3.
  10. 10. preparation method according to claim 4, it is characterised in that：Step 2) is as follows, step 1) is obtained To the metal-doped metal-doped hypophosphite monohydrate iron of hypophosphite monohydrate ferrous iron and N of M be mixed in a certain ratio after, and with phosphorus source, Lithium source and carbon source are first sanded, and through drying, then calcining obtains how metal-doped lithium iron phosphate/carbon composite wood in a nitrogen atmosphere Material.
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110797531A (en) * 2019-10-11 2020-02-14 合肥国轩高科动力能源有限公司 Microwave-grafting graphene treatment method and modification method for improving high-rate discharge performance of lithium iron phosphate by using same
CN112563469A (en) * 2020-12-09 2021-03-26 中南大学 Novel three-phase composite positive electrode material and preparation method thereof
CN114538401A (en) * 2021-07-12 2022-05-27 万向一二三股份公司 Preparation method of high-compaction lithium iron phosphate
CN114804056A (en) * 2022-05-25 2022-07-29 湖北融通高科先进材料有限公司 Carbon-coated high-capacity lithium manganese iron phosphate material and preparation method and application thereof
WO2022242184A1 (en) * 2021-05-17 2022-11-24 广东邦普循环科技有限公司 Doped iron phosphate, and preparation method therefor and application thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101789502A (en) * 2010-03-12 2010-07-28 江苏工业学院 Metal ion doping and carbon coating jointly modified lithium ion battery anode material
CN103066286A (en) * 2013-01-25 2013-04-24 浙江南都电源动力股份有限公司 Vanadium-antimony co-doped lithium iron phosphate used as lithium ion positive pole material and preparation method thereof
CN103078113A (en) * 2013-01-15 2013-05-01 浙江南都电源动力股份有限公司 Vanadium-titanium ion-codoped lithium iron phosphate material and preparation method thereof
CN103094569A (en) * 2013-01-30 2013-05-08 芜湖华欣诺电化学科技有限公司 Anode material-nanometer vanadium iron manganese lithium phosphate of lithium ion battery and preparation method of anode material
CN104037411A (en) * 2014-05-18 2014-09-10 深圳赛骄阳能源科技有限公司 Multielement doped lithium phosphate anode material and preparation method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101789502A (en) * 2010-03-12 2010-07-28 江苏工业学院 Metal ion doping and carbon coating jointly modified lithium ion battery anode material
CN103078113A (en) * 2013-01-15 2013-05-01 浙江南都电源动力股份有限公司 Vanadium-titanium ion-codoped lithium iron phosphate material and preparation method thereof
CN103066286A (en) * 2013-01-25 2013-04-24 浙江南都电源动力股份有限公司 Vanadium-antimony co-doped lithium iron phosphate used as lithium ion positive pole material and preparation method thereof
CN103094569A (en) * 2013-01-30 2013-05-08 芜湖华欣诺电化学科技有限公司 Anode material-nanometer vanadium iron manganese lithium phosphate of lithium ion battery and preparation method of anode material
CN104037411A (en) * 2014-05-18 2014-09-10 深圳赛骄阳能源科技有限公司 Multielement doped lithium phosphate anode material and preparation method

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
DING YAN-HUAI,ZHANG PING: "Effect of Mg and Co co-doping on electrochemical properties of LiFePO4", 《TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA》 *
JIGUO TU,KAI WU,HUI TANG等: "Mg–Ti co-doping behavior of porous LiFePO4 microspheres for high-rate lithium-ion batteries", 《JOURNAL OF MATERIAL CHEMISTRY A》 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110797531A (en) * 2019-10-11 2020-02-14 合肥国轩高科动力能源有限公司 Microwave-grafting graphene treatment method and modification method for improving high-rate discharge performance of lithium iron phosphate by using same
CN110797531B (en) * 2019-10-11 2022-04-12 合肥国轩高科动力能源有限公司 Microwave-grafting graphene treatment method and modification method for improving high-rate discharge performance of lithium iron phosphate by using same
CN112563469A (en) * 2020-12-09 2021-03-26 中南大学 Novel three-phase composite positive electrode material and preparation method thereof
WO2022242184A1 (en) * 2021-05-17 2022-11-24 广东邦普循环科技有限公司 Doped iron phosphate, and preparation method therefor and application thereof
CN114538401A (en) * 2021-07-12 2022-05-27 万向一二三股份公司 Preparation method of high-compaction lithium iron phosphate
CN114804056A (en) * 2022-05-25 2022-07-29 湖北融通高科先进材料有限公司 Carbon-coated high-capacity lithium manganese iron phosphate material and preparation method and application thereof
CN114804056B (en) * 2022-05-25 2023-08-15 湖北融通高科先进材料集团股份有限公司 Carbon-coated high-capacity lithium iron manganese phosphate material and preparation method and application thereof

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