CN109192965A - A kind of preparation method of LiFePO4/graphene composite material - Google Patents

A kind of preparation method of LiFePO4/graphene composite material Download PDF

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CN109192965A
CN109192965A CN201811155988.3A CN201811155988A CN109192965A CN 109192965 A CN109192965 A CN 109192965A CN 201811155988 A CN201811155988 A CN 201811155988A CN 109192965 A CN109192965 A CN 109192965A
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lifepo4
composite material
graphene composite
lithium
preparation
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刘艳
张登科
杨露
王洁
曹晶媛
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Shanghai Institute of Technology
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Shanghai Institute of Technology
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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
    • H01M4/366—Composites as layered products
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The present invention provides a kind of preparation methods of LiFePO4/graphene composite material.The present invention prepares lithium iron phosphate positive material using solvent-thermal method using lithium source, phosphoric acid root, source of iron as raw material, and the graphene of different proportion is added during the preparation process, and is heat-treated in inert gas, final to obtain a kind of LiFePO4/graphene composite material.LiFePO4/the graphene composite material obtained after graphene, the mutually single free from admixture of object is added compared to original LiFePO4 in the present invention, and particle size reduces, and chemical property obtains different degrees of raising.Resulting LiFePO4/graphene composite material improves the cycle performance of lithium battery for the anode of chargeable lithium ion battery.

Description

A kind of preparation method of LiFePO4/graphene composite material
Technical field
The present invention relates to a kind of preparation method of LiFePO4/graphene composite material, which can be used as lithium-ion electric The positive electrode in pond.
Background technique
In recent ten years, lithium ion battery has been widely used in mobile electronic terminal device neck with its high-performance benefits Domain.LiFePO4Positive electrode has many advantages, such as that energy density is high, the service life is long, safety is good, theoretical specific capacity 170mAh g-1.The sample is free of any poisonous and hazardous heavy metal element, is anode material for lithium-ion batteries the safest so far, And sustainable charge and discharge are up to 2000 times or more.
However LiFePO4There are the problem of mainly have the following: (1) conductivity is low, under room temperature only 10-11-10-9S·cm-1, it is only suitable for the charge and discharge under low current；(2)Fe2+It is oxidized easily, when reaction needs to carry out strict protection, is not easy Realize industrialization；(3)Li+Diffusion admittance is longer, and diffusion velocity is slow, and the diffusion coefficient of ion is only 1.8 × 10-14cm2·S； (4) tap density of product is low, and median particle diameter is between 2-6 μm, to limit the chemical property of material；(5) battery Poor performance at low temperatures, it is 40-55% at -10 DEG C that material capacity retention ratio under the conditions of 0 DEG C, which is 60-70%, at -20 DEG C only 20-40%.
For disadvantage mentioned above, main solution has: (1) reducing particle size；(2) material with carbon-coated surface；(3) doping metals Ion.
Summary of the invention
The object of the present invention is to provide the LiFePO4 of a kind of charge/discharge capacity with higher and good cycle performance/ The preparation method of graphene composite material.
In order to achieve the above object, the present invention provides a kind of preparation method of LiFePO4/graphene composite material, It is characterized in that, comprising:
Step 1: in organic solvent by the dissolution of 113~280 parts by weight lithium sources, 147~173 weight being added dropwise in whipping process The phosphoric acid root of part；
Step 2: the source of iron dissolution of 187~404 parts by weight being made into source of iron solution in organic solvent, to institute in step 1 When white suspension object occurs in the solution obtained, source of iron solution is added in the resulting solution of step 1, continues to stir, it will be resulting Hydro-thermal reaction is carried out in the autoclave of mixed solution immigration inner liner polytetrafluoroethylene；
Step 3: the resulting reaction solution of step 2 being centrifuged, resulting solid content washing, drying will be centrifuged, obtained powdered Mix presoma；
Step 4: the resulting powder-mixed presoma of step 3 being mixed with Kynoar, is heat-treated, obtains phosphorus Sour iron lithium powder；
Step 5: in water by graphene ultrasonic disperse, iron phosphate powder is added, it is ultrasonic after mixing evenly, it will be resulting Reaction solution is centrifuged, by the washing of centrifugation gained solid content, drying, under nitrogen atmosphere or argon atmosphere, at 500-700 DEG C 1-3h is kept the temperature, LiFePO4/graphene composite material is obtained.
Preferably, the weight ratio of powder-mixed presoma and Kynoar is 1:0.12- in the step 4 0.25。
Preferably, the weight content of graphene is 1-3% in the LiFePO4/graphene composite material.
Preferably, the graphene is graphene oxide.
Preferably, LiFePO4/graphene composite material partial size is 0.372~2.009 μm.
Preferably, the organic solvent in the step 1 and step 2 is ethylene glycol.
Preferably, the lithium source in the step 1 is lithium dihydrogen phosphate, lithium hydroxide, lithium carbonate, lithium nitrate and chlorination One of lithium is a variety of, more preferably lithium hydroxide.
Preferably, the phosphoric acid root in the step 1 is one of phosphoric acid, ammonium hydrogen phosphate or ammonium dihydrogen phosphate or more Kind, more preferably phosphoric acid.
Preferably, the time for continuing stirring in the step 2 is 30~60min.
Preferably, the temperature of the hydro-thermal reaction is 140~220 DEG C, and the time is 3~15h.
Preferably, the filling degree of the autoclave is 60-80%.
Preferably, the source of iron is one of ferric phosphate, ferric nitrate or ferrous sulfate or a variety of, more preferably sulfuric acid It is ferrous.
Preferably, the revolving speed of the centrifugation in the step 3 is 3000~3500r/min, and the time is 30~60min.
Preferably, the revolving speed of the centrifugation in the step 5 is 3000~3500r/min, and the time is 30~60min.
Preferably, the heat treatment in the step 4 carries out in nitrogen atmosphere or argon atmosphere.
Compared with prior art, the beneficial effects of the present invention are:
The present invention prepares lithium iron phosphate positive material using solvent-thermal method using lithium source, phosphoric acid root, source of iron as raw material, The graphene of different proportion is added during the preparation process, and is heat-treated in inert gas, it is final to obtain a kind of LiFePO4/graphite Alkene composite material.LiFePO4/graphene the composite wood obtained after graphene is added compared to original LiFePO4 in the present invention Material, the mutually single free from admixture of object, particle size reduce, and chemical property obtains different degrees of raising.Resulting LiFePO4/ Graphene composite material improves the cycle performance of lithium battery for the anode of chargeable lithium ion battery.
Detailed description of the invention
The XRD diagram of the resulting LiFePO4/graphene composite material of Fig. 1, Application Example；
The particle diameter distribution situation of the resulting LiFePO4/graphene composite material of Fig. 2, Application Example: (a) different samples D10, D50, D90 value；(b) grain size distribution of different samples；
Voltage-specific volume spirogram of the resulting LiFePO4/graphene composite material of Fig. 3, Application Example under 1C multiplying power；
Cycle charge-discharge of the resulting LiFePO4/graphene composite material of Fig. 4, Application Example under 15C multiplying power is bent Line.
Specific embodiment
Present invention will be further explained below with reference to specific examples.It should be understood that these embodiments are merely to illustrate the present invention Rather than it limits the scope of the invention.In addition, it should also be understood that, after reading the content taught by the present invention, those skilled in the art Member can make various changes or modifications the present invention, and such equivalent forms equally fall within the application the appended claims and limited Range.
Embodiment 1
A kind of preparation method of LiFePO4/graphene composite material, specific steps are as follows:
(1) by 1.13g lithium hydroxide (LiOHH2O analyzes pure, Chinese medicines group chemical reagents corporation) it is dissolved in 30mL second Glycol ((CH2OH)2, analyze pure, Chinese medicines group chemical reagents corporation) in, entire adition process magnetic agitation (81-2 type, on Hai Sile Instrument Ltd.) under carry out, 1.47g phosphoric acid solution (H is slowly added dropwise in whipping process3PO4, analyze pure, traditional Chinese medicines collection Chemical reagents corporation of group, concentration 85-97%).
(2) 2.78g green vitriol (FeSO4·7H2O analyzes pure, Chinese medicines group chemical reagents corporation) it is dissolved in It is resulting to be added to step (1) when white suspension object occurs in solution in (1) by wiring solution-forming in 30mL ethylene glycol for this solution In solution, continue to stir 30min.Entire mixed solution is moved into autoclave (100ml, the positive letter of inner liner polytetrafluoroethylene Instrument plant) in carry out hydro-thermal reaction, fillings degree be 75%, control hydrothermal temperature be 180 DEG C, time 10h must react Liquid；
(3) it washs and dries to obtain powder-mixed presoma；
Step (2) resulting reaction solution is centrifuged, it is 3000r/min that centrifugal process, which controls centrifugal rotational speed, and the time is 20min, solid content deionized water and dehydrated alcohol (analyzing pure, one factory of Shanghai development chemical industry) after resulting centrifugation, is respectively washed After washing 3 times, is dried controlled at 70 DEG C, obtain powder-mixed presoma；
(4) in order to carry out carbon coating, by the resulting powder-mixed presoma of step (3) and Kynoar (- (CH2CF2)n, analyze pure, Chinese medicines group chemical reagents corporation, molecular weight 825000) and it is mixed according to weight ratio 1:0.25, and 500 DEG C of heat treatment 2h in a nitrogen atmosphere, obtain iron phosphate powder (being denoted as LFP)；
(5) 0.07g graphene oxide (first rich nanometer Co., Ltd, No:XF002-1) is passed through into ultrasonic cleaner (KQ 3200 DE, Kunshan ultrasonic wave) ultrasonic disperse in 20mL deionized water, then be added step (4) resulting LiFePO4 powder The weight ratio of end, graphene oxide and LiFePO4 is 1.5:98.5, after mixing evenly ultrasound (ultrasound works frequency is 25KHz) 2h,.Resulting reaction solution is centrifuged, centrifugal process control centrifugal rotational speed be 3000r/min, time 20min, it is resulting After solid content deionized water and dehydrated alcohol after centrifugation respectively wash 3 times, is dried controlled at 80 DEG C, obtain powder-mixed Body；
(6) in a nitrogen atmosphere by the resulting powder-mixed body of step (5), 2h is kept the temperature at 600 DEG C can obtain oxidation stone LiFePO4/graphene composite material (being denoted as LFP-G 15) that black alkene content is 1.5%.
Embodiment 2
(1) by 1.13g lithium hydroxide (LiOHH2O analyzes pure, Chinese medicines group chemical reagents corporation) it is dissolved in 30mL second Glycol ((CH2OH)2, analyze pure, Chinese medicines group chemical reagents corporation) in, entire adition process magnetic agitation (81-2 type, on Hai Sile Instrument Ltd.) under carry out, 1.47g phosphoric acid solution (H is slowly added dropwise in whipping process3PO4, analyze pure, traditional Chinese medicines collection Chemical reagents corporation of group, concentration 85-97%).
(2) by 2.78g green vitriol (FeSO4·7H2O analyzes pure, Chinese medicines group chemical reagents corporation) dissolution It is resulting to be added to step (1) when white suspension object occurs in (1) solution by the wiring solution-forming in 30mL ethylene glycol for this solution In solution, continue to stir 30min.Entire mixed solution is moved into autoclave (100ml, the positive letter of inner liner polytetrafluoroethylene Instrument plant) in carry out hydro-thermal reaction, fillings degree be 75%, control hydrothermal temperature be 180 DEG C, time 10h must react Liquid；
(3) it washs and dries to obtain powder-mixed presoma；
Step (2) resulting reaction solution is centrifuged, it is 3500r/min that centrifugal process, which controls centrifugal rotational speed, and the time is 30min, solid content deionized water and dehydrated alcohol (analyzing pure, one factory of Shanghai development chemical industry) after resulting centrifugation, is respectively washed After washing 3 times, is dried controlled at 70 DEG C, obtain powder-mixed presoma；
(4) in order to carry out carbon coating, by the resulting powder-mixed presoma of step (3) and Kynoar (- (CH2CF2)n, analyze pure, Chinese medicines group chemical reagents corporation, molecular weight 825000) and it is mixed according to weight ratio 1:0.25, and 600 DEG C of heat treatment 2h in a nitrogen atmosphere, obtain iron phosphate powder (being denoted as LFP)；
(5) graphene oxide of 0.15g (first rich nanometer Co., Ltd, No:XF002-1) is passed through into ultrasonic cleaner (KQ 3200DE, Kunshan ultrasonic wave) ultrasonic disperse is in 20mL deionized water.Then step (4) resulting LiFePO4 is added The weight ratio of powder, graphene oxide and LiFePO4 is 2:98, after mixing evenly ultrasound (ultrasound works frequency is 25KHz) 2h.Resulting reaction solution is centrifuged, centrifugal process control centrifugal rotational speed be 3500r/min, time 30min, it is resulting After solid content deionized water and dehydrated alcohol after centrifugation respectively wash 3 times, is dried controlled at 80 DEG C, obtain powder-mixed Body；
(6) in a nitrogen atmosphere by the resulting powder-mixed body of step (5), 2h is kept the temperature at 600 DEG C can obtain oxidation stone LiFePO4/graphene composite material (being denoted as LFP-G 20) that black alkene content is 2.0%.
Embodiment 3
(1) by 1.13g lithium hydroxide (LiOHH2O analyzes pure, Chinese medicines group chemical reagents corporation) it is dissolved in 30mL second Glycol ((CH2OH)2, analyze pure, Chinese medicines group chemical reagents corporation) in, entire adition process magnetic agitation (81-2 type, on Hai Sile Instrument Ltd.) under carry out, 1.47g phosphoric acid solution (H is slowly added dropwise in whipping process3PO4, analyze pure, traditional Chinese medicines collection Chemical reagents corporation of group, concentration 85-97%).
(2) by 2.78g green vitriol (FeSO4·7H2O analyzes pure, Chinese medicines group chemical reagents corporation) dissolution It is resulting to be added to step (1) when white suspension object occurs in (1) solution by the wiring solution-forming in 30mL ethylene glycol for this solution In solution, continue to stir 30min.Entire mixed solution is moved into autoclave (100ml, the positive letter of inner liner polytetrafluoroethylene Instrument plant) in carry out hydro-thermal reaction, fillings degree be 75%, control hydrothermal temperature be 180 DEG C, time 10h must react Liquid；
(3) it washs and dries to obtain powder-mixed presoma；
Step (2) resulting reaction solution is centrifuged, it is 3300r/min that centrifugal process, which controls centrifugal rotational speed, and the time is 25min, solid content deionized water and dehydrated alcohol (analyzing pure, one factory of Shanghai development chemical industry) after resulting centrifugation, is respectively washed After washing 3 times, is dried controlled at 70 DEG C, obtain powder-mixed presoma；
(4) in order to carry out carbon coating, by the resulting powder-mixed presoma of step (3) and Kynoar (- (CH2CF2)n, analyze pure, Chinese medicines group chemical reagents corporation, molecular weight 825000) and it is mixed according to weight ratio 1:0.25, and 700 DEG C of heat treatment 3h in a nitrogen atmosphere, obtain iron phosphate powder (being denoted as LFP)；
(5) 0.23g graphene oxide (first rich nanometer Co., Ltd, No:XF002-1) is passed through into ultrasonic cleaner (KQ3200DE, Kunshan ultrasonic wave) ultrasonic disperse is in 20mL deionized water.Then step (4) resulting LiFePO4 powder is added The weight ratio of end, graphene oxide and LiFePO4 is 2.5:97.5, after mixing evenly ultrasound (ultrasound works frequency is 25KHz) 2h.Resulting reaction solution is centrifuged, centrifugal process control centrifugal rotational speed be 3300r/min, time 25min, it is resulting After solid content deionized water and dehydrated alcohol after centrifugation respectively wash 3 times, is dried controlled at 80 DEG C, obtain powder-mixed Body；
(6) in a nitrogen atmosphere by the resulting powder-mixed body of step (5), 2h is kept the temperature at 600 DEG C can obtain oxidation stone LiFePO4/graphene composite material (being denoted as LFP-G 25) that black alkene content is 2.5%.
Application Example
The preparation of LiFePO4/Graphene electrodes positive electrode, steps are as follows:
LiFePO4/graphene composite material in mass ratio: acetylene black (LITHIUM BATTERY, Xiang Tan Battery Plant): binder is (poly- inclined Difluoroethylene (PVDF) analyzes pure, Chinese medicines group chemical reagents corporation)=80:10:10, it respectively will be prepared by Examples 1 to 3 LiFePO4/graphene composite material be uniformly mixed with acetylene black and binder and be dissolved in N-Methyl pyrrolidone respectively In (NMP, chemistry is pure, and Solution on Chemical Reagents in Shanghai purchase and supply is without connection chemical plant), it is coated in processed aluminum foil current collector (11 milli of diameter Rice, Beijing Non-Fervoous Metal Inst.) on, coating thickness 0.2mm in 100 DEG C of vacuum, dries 12h, obtains corresponding by embodiment 1 LiFePO4 made of LiFePO4/graphene composite material prepared by~3/Graphene electrodes positive electrode.
It is respectively anode with above-mentioned resulting LiFePO4/Graphene electrodes material, (Beijing non-ferrous metal is ground metal lithium sheet Study carefully institute (purity 99.9%)) be cathode, polypropylene (PP, technical grade, oil of SPC Products) as between positive and negative anodes every Film, 0.0025g 1M LiPF6And ethylene carbonate (EC) and diethyl carbonate (DEC) mixing of 0.00012g 50:50 (w/w) Liquid is electrolyte (Guotai Huarong Chemical New Material Co., Ltd., Zhangjiagang City), in glove box (ZKX type, the Nanjing of argon gas protection Instrument plant of university) it is inner be assembled into battery, it is obtained to Examples 1 to 3 using X-ray diffraction (XRD, Rigaku Rigaku) LiFePO4/graphene powder is detected；It uses particle diameter distribution tester (Baite Instrument Co., Ltd., Dandong's offer) point The particle size for analysing sample, determines particle diameter distribution situation；In Land battery test system, (Wuhan Lan electricity Electronics Co., Ltd. is mentioned For) under carry out constant current density under charge and discharge test.Test environment is 25 DEG C of constant temperature.
LFP, LFP-G 15, the LFP-G 20 and 25 4 samples of LFP-G that are tested are compared, shown in Fig. 1 Show that the diffraction maximum of four samples can index the space structure (JCPDS card No.81-1173) of rhombic system, this shows to synthesize LiFePO4With preferable crystal structure.Impurity diffraction maximum is not observed, this shows LFP, LFP-G 15, LFP-G 20 With 25 4 sample purity with higher of LFP-G.By comparison it can be found that the diffraction peak intensity of LFP sample is minimum, say The crystallinity of the bright sample particle is poor；The diffraction peak intensity highest of LFP-G 20 illustrates that the crystallinity of particle is high, and crystallinity is high Sample, chemical property also can be more excellent.In Fig. 2 grain size distribution: the D of different samples (a) being shown in figure 10,D 50,D 90.Generally using 50 value of D as judgment criteria.As can be seen that LFP, LFP-G 15, LFP-G 20 from (a) figure 50 value of D with 25 4 samples of LFP-G is respectively 2.009 μm, 1.897 μm, 0.372 μm and 0.805 μm, wherein LFP-G 50 value of D of 20 samples is minimum in four samples, we can be assumed that 20 sample particle size of LFP-G is in four samples It is the smallest；As can be seen that the grading curve of four samples is in normal distribution from (b) figure.In four samples, LFP-G 20 The curve of sample illustrates its particle size minimum near the left side；From figure 3, it can be seen that the electric discharge specific volume of 20 sample of LFP-G Amount is 139mAhg-1, highest in four samples；The specific discharge capacity of LFP sample is 121mAhg-1, in four samples most It is low, in conjunction with the discharge scenario of 25 two samples of LFP-G 15 and LFP-G, it follows that, the addition of graphene can be significant Improve the specific discharge capacity of material.Figure 4, it is seen that LFP, LFP-G 15, LFP-G 20 and 25 4 samples of LFP-G Maximum specific discharge capacity be respectively 85.4,102.3,113.4 and 105.1mAhg-1, after circulation 2000 is enclosed, discharge specific volume Amount is followed successively by 40.5,58.9,96.1 and 74.7mAhg-1, the capacity retention ratio after four cycles samples 2000 enclose is respectively 47.4,57.6,84.7 and 71.1%.Due to the addition of graphene, the cyclical stability of material can be significantly improved, and works as and adds The content of the graphene added be 2.0% when, show chemical property is more excellent.
Above content is only the basic explanation under present inventive concept, and any etc. made by technical solution according to the present invention Effect transformation, is within the scope of protection of the invention.

Claims (10)

1. a kind of preparation method of LiFePO4/graphene composite material characterized by comprising
Step 1: in organic solvent by the dissolution of 113~280 parts by weight lithium sources, 147~173 parts by weight being added dropwise in whipping process Phosphoric acid root；
Step 2: the source of iron dissolution of 187~404 parts by weight being made into source of iron solution in organic solvent, to obtained in step 1 When white suspension object occurs in solution, source of iron solution is added in the resulting solution of step 1, continues to stir, by resulting mixing Hydro-thermal reaction is carried out in the autoclave of solution immigration inner liner polytetrafluoroethylene；
Step 3: the resulting reaction solution of step 2 being centrifuged, resulting solid content washing, drying will be centrifuged, obtain powder-mixed Presoma；
Step 4: the resulting powder-mixed presoma of step 3 being mixed with Kynoar, is heat-treated, obtains ferric phosphate Lithium powder；
Step 5: in water by graphene ultrasonic disperse, iron phosphate powder is added, it is ultrasonic after mixing evenly, by resulting reaction Liquid is centrifuged, and the washing of centrifugation gained solid content, drying under nitrogen atmosphere or argon atmosphere, are kept the temperature at 500-700 DEG C 1-3h obtains LiFePO4/graphene composite material.
2. the preparation method of LiFePO4/graphene composite material as described in claim 1, which is characterized in that the phosphorus The partial size of sour iron lithium/graphene composite material is 0.372~2.009 μm.
3. the preparation method of LiFePO4/graphene composite material as described in claim 1, which is characterized in that the step Rapid 1 and step 2 in organic solvent be ethylene glycol.
4. the preparation method of LiFePO4/graphene composite material as described in claim 1, which is characterized in that the step Lithium source in rapid 1 is one of lithium dihydrogen phosphate, lithium hydroxide, lithium carbonate, lithium nitrate and lithium chloride or a variety of；Described Phosphoric acid root in step 1 is one of phosphoric acid, ammonium hydrogen phosphate or ammonium dihydrogen phosphate or a variety of；The source of iron is phosphoric acid One of iron, ferric nitrate or ferrous sulfate are a variety of.
5. the preparation method of LiFePO4/graphene composite material as described in claim 1, which is characterized in that the step The time for continuing stirring in rapid 2 is 30~60min.
6. the preparation method of LiFePO4/graphene composite material as described in claim 1, which is characterized in that the water The temperature of thermal response is 140~220 DEG C, and the time is 3~15h.
7. the preparation method of LiFePO4/graphene composite material as described in claim 1, which is characterized in that.
8. the preparation method of LiFePO4/graphene composite material as described in claim 1, which is characterized in that the step The revolving speed of centrifugation in rapid 3 is 3000~3500r/min, and the time is 30~60min；The revolving speed of centrifugation in the step 5 For 3000~3500r/min, the time is 30~60min.
9. the preparation method of LiFePO4/graphene composite material as described in claim 1, which is characterized in that the step Heat treatment in rapid 4 carries out in nitrogen atmosphere or argon atmosphere.
10. the preparation method of LiFePO4/graphene composite material as described in claim 1, which is characterized in that the stone Black alkene is graphene oxide.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115180609A (en) * 2022-08-11 2022-10-14 国环电池科技(苏州)有限公司 Lithium iron phosphate preparation process suitable for industrialization

Citations (3)

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Application publication date: 20190111