CN106784744A - LiFePO4 and preparation method thereof - Google Patents
LiFePO4 and preparation method thereof Download PDFInfo
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- CN106784744A CN106784744A CN201710121320.6A CN201710121320A CN106784744A CN 106784744 A CN106784744 A CN 106784744A CN 201710121320 A CN201710121320 A CN 201710121320A CN 106784744 A CN106784744 A CN 106784744A
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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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
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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
- 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
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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
- H01M4/58—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
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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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
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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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
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- 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
Present invention is disclosed a kind of lithium iron phosphate preparation method, including：The source of iron of the amount ratio of certain material, lithium source and phosphorus source are added separately to according to a graded to be stirred in decentralized medium, appropriate organic carbon source is added, ferric lithium phosphate precursor slurries are configured to；The pre-prepared AAO templates with specified pore-size distribution are put in closed container, are extracted out the air in AAO templates by vacuum filtration machine, then under suction function, the ferric lithium phosphate precursor slurries injected in the hole of AAO templates, and vacuum drying；The AAO templates that ferric lithium phosphate precursor will be loaded with are sintered under certain atmosphere, and remove AAO templates with NaOH solution, and the LiFePO4 of nano-wire array pattern is obtained.LiFePO4 of the invention possesses nano-wire array pattern, shortens the tortuous and distance of insertion and the abjection of lithium ion, realizes high power charging-discharging.
Description
Technical field
The present invention relates to new energy field, LiFePO4 and preparation method thereof is especially related to.
Background technology
The performance of lithium ion battery depends primarily on positive and negative pole material, LiFePO4 as lithium ion battery positive pole material
Material, its security performance is compared with other materials are cannoted with cycle life, these also exactly most important technologies of electrokinetic cell
Index.1C charge and discharges cycle life is up to 2000 times.Single battery overcharged voltage 30V is not burnt, and puncture is not exploded.Iron phosphate lithium positive pole
Material makes high capacity lithium ion battery and is more easy to be used in series.The need for meet the frequent discharge and recharge of electric motor car.And ferric phosphate
Lithium have it is nontoxic, pollution-free, have a safety feature, raw material sources are extensive, cheap, are lithiums of new generation the advantages of long lifespan
The preferable positive electrode of ion battery.The low shortcoming of LiFePO4 LiFePO4 poorly conductive, bulk density hinders material
Practical application.
At present, the problem for improving LiFePO4 electrical conductivity difference and lithium ion diffusion rate difference mainly has three kinds of approach：1) lead to
Cross conductive carbon coating and improve electrical conductivity；2) by mixing transition metal；3) specific surface of lithium ion is improved by crystal grain thinning
Product.The tap density of LiFePO4 can be further reduced using coated with conductive carbon or by the way of reducing particle diameter so that volume energy
Density reduction；Can increase side reaction and complex procedures by the way of other transition metal that adulterate, increased cost.
Therefore, prior art could be improved.
The content of the invention
The main object of the present invention is a kind of LiFePO4 of offer and preparation method thereof, it is intended to solve LiFePO4 electrical conductivity
The problem of difference and lithium ion diffusion rate difference.
The present invention proposes a kind of lithium iron phosphate preparation method, including：
The source of iron of the amount ratio of certain material, lithium source and phosphorus source are added separately to according to a graded to be stirred in decentralized medium
Mix uniform, form stabilization mixture, then to appropriate organic carbon source is added in the stabilization mixture, dispersed with stirring is uniform, matches somebody with somebody
It is made ferric lithium phosphate precursor slurries；
The pre-prepared AAO templates with specified pore-size distribution are put in closed container, by vacuum filtration machine by AAO
Air in template is extracted out, then under suction function, the ferric lithium phosphate precursor slurries colloidal sol is injected the hole of AAO templates
In hole, and vacuum drying；
The AAO templates that ferric lithium phosphate precursor will be loaded with are sintered under certain atmosphere, and remove AAO moulds with NaOH solution
Plate, is obtained the LiFePO4 of nano-wire array pattern.
Preferably, in the amount ratio by certain material source of iron, lithium source and phosphorus source are separately added into according to a graded
Stirred in decentralized medium, form stabilization mixture, then to appropriate organic carbon source is added in the stabilization mixture, stir
Mix and be uniformly dispersed, the step of be configured to ferric lithium phosphate precursor slurries before, also including step：Electrochemistry throwing is carried out to aluminium flake
Light, is then aoxidized with the acid solution with oxidisability, then with weak acid mixed solution, the oxide layer of removal oxidation generation,
Prepare AAO templates.
Preferably, the condition of the electrochemical polish is：The use of volume proportion is 1:4 perchloric acid ethanol solution is polishing
Liquid, the electrochemical polish time is 3-5min, and voltage range is 15-25V；The oxidizing condition is：Use the grass with oxidisability
Acid solution is aoxidized, and oxidization time is 6-12h, and voltage range is 40-60V, and the concentration of the oxalic acid solution is 0.1-5mol/
L。
Preferably, the AAO templates are the AAO templates that expanding treatment has been carried out by the phosphoric acid solution of 5-10wt%.
Preferably, the AAO pore size of template of the expanding treatment is 80 to 100nm, and thickness is 8 to 12 μm.
Preferably, the organic carbon source includes one or more in citric acid, acrylic acid, glucose.
Preferably, the ferric lithium phosphate precursor concentration of slurry is 0.05-0.2mol/L.
Preferably, the atmosphere includes Ar gas, N of the purity more than 99.99%2Gas, Ar and N2Mixed gas, Ar and H2
Mixed gas and N2With H2Mixed gas.
Preferably, the AAO templates for being loaded with ferric lithium phosphate precursor, sintering condition is 600-700 under reducing atmosphere
DEG C sintering 10-15h.
Present invention also offers a kind of LiFePO 4 material, it is obtained by above-mentioned preparation method, the LiFePO 4 material
Possesses nano-wire array pattern, the nanowire diameter is 70 to 80nm.
Advantageous Effects of the present invention：The lithium iron phosphate nano linear array that the present invention is prepared, forms flat between nano wire
Row lithium ion transfer passage, it will shorten the tortuous and distance of insertion and the abjection of lithium ion, increase and electrolyte
Contact area, is remarkably improved active material utilization, realizes high power charging-discharging, can solve current lithium iron phosphate positive material
The not enough problem of power density.And nano wire is in addition to the advantage for possessing nano-particle, conductive carbon is also coated, particle can have been eliminated
Between contact resistance, while improve electrical conductivity and ion diffusion rates.
Brief description of the drawings
Lithium iron phosphate preparation method schematic flow sheet in Fig. 1 one embodiment of the invention；
AAO templates SEM figures in Fig. 2 one embodiment of the invention before reaming；
The AAO templates SEM figures of expanding treatment in Fig. 3 one embodiment of the invention；
The AAO templates SEM figures of LiFePO4 are loaded in Fig. 4 one embodiment of the invention；
Lithium iron phosphate nano linear array SEM figures in Fig. 5 one embodiment of the invention；
LiFePO in Fig. 6 one embodiment of the invention4Nano particle SEM schemes；
LiFePO in Fig. 7 one embodiment of the invention4The CV curve maps of battery corresponding to nano particle and nano-wire array；
LiFePO in Fig. 8 one embodiment of the invention4The high rate performance figure of battery corresponding to nano particle and nano-wire array.
The realization of the object of the invention, functional characteristics and advantage will be described further referring to the drawings in conjunction with the embodiments.
Specific embodiment
It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not intended to limit the present invention.
Reference picture 1, the embodiment of the present invention proposes a kind of lithium iron phosphate preparation method, including：
S1:The source of iron of the amount ratio of certain material, lithium source and phosphorus source are added separately to decentralized medium according to a graded
In stir, formed stabilization mixture, then to it is described stabilization mixture in add appropriate organic carbon source, dispersed with stirring is equal
It is even, it is configured to ferric lithium phosphate precursor slurries；
S2：The pre-prepared AAO templates with specified pore-size distribution are put in closed container, will by vacuum filtration machine
Air in AAO templates is extracted out, then under suction function, the ferric lithium phosphate precursor slurries is injected the hole of AAO templates
In hole, and vacuum drying；
S3：The AAO templates that ferric lithium phosphate precursor will be loaded with are sintered under certain atmosphere, and are removed with NaOH solution
AAO templates, are obtained the LiFePO4 of nano-wire array pattern.
Further, in the above-mentioned amount ratio by certain material source of iron, lithium source and phosphorus source add respectively according to a graded
Enter and stirred in decentralized medium, formed stabilization mixture, then to it is described stabilization mixture in add appropriate organic carbon source,
Dispersed with stirring is uniform, the step of be configured to ferric lithium phosphate precursor slurries before S1, also including step S10：Electricity is carried out to aluminium flake
Chemical polishing, is then aoxidized with the acid solution with oxidisability, then with weak acid mixed solution, the oxygen of removal oxidation generation
Change layer, prepare AAO templates, to optimize the pre-prepared AAO pore size of template distribution situations, repeat above-mentioned oxidation, go
Oxidation step is for several times.
The embodiment of the present invention is improved in terms of material structure, and performance is carried out by preparing lithium iron phosphate nano linear array
Improve.The three-dimensional structure LiFePO 4 material of nano-wire array, effectively improves that existing LiFePO4 electrical conductivity is low, lithium ion expands
The drawbacks of dissipating low speed and corresponding high-power charge-discharge performance difference.It is highly directional compared with other zero dimensions, monodimension nanometer material
Co-axial nano linear array there is the effective interface that specific surface area higher and lithium ion spread, be conducive to shortening lithium ion in electricity
Diffusion length in extremely, increases the wellability with electrolyte, improves the electrical conductivity of LiFePO4, improves power-performance；Originally simultaneously
The carbon-coating that inventive embodiments are coated in nanowire surface, shortens lithium ion expansion in the electrodes while materials conductive rate is improved
Dissipate specific, increase the wellability with electrolyte, be conducive to further improving the electrical conductivity of LiFePO 4 material, improve its electrochemistry
Performance.
Further, the condition of above-mentioned electrochemical polish is：The use of volume proportion is 1:4 perchloric acid ethanol solution is throwing
Light liquid, the electrochemical polish time is 3-5min, and voltage range is 15-25V；The oxidizing condition is：Using with oxidisability
Oxalic acid solution is aoxidized, and oxidization time is 6-12h, and voltage range is 40-60V, and the concentration of the oxalic acid solution is 0.1-
5mol/L。
Electrochemical polish is the chemical attack under a kind of specific condition, by selecting suitable polishing fluid, suitable polishing
Condition, makes metal surface progressively reach leveling and light.Compared to mechanical polishing, the microcosmic surface after electrochemical polish is more flat
It is sliding, it is simple to operate, and do not limited by workpiece size and shape.
Oxidation electrolyte described in the embodiment of the present invention can be the acid solutions with oxidisability such as sulfuric acid, phosphoric acid, but by
It is weak acid in oxalic acid, oxidisability is moderate, AAO templates (the Anodic Aluminum OxideTemplate, abbreviation AAO moulds for making
Plate) arrange more regular；Meanwhile, during compared to doing AAO templates using other acid, required voltage conditions harshness (need to typically reach
More than 160V), and the AAO template regularities made are generally poor, and hole diameter is uneven.So in the embodiment of the present invention
It is preferred that 0.1-5mol/L oxalic acid solutions are used as oxidation electrolyte.
Further, above-mentioned AAO templates are the AAO templates that expanding treatment has been carried out by the phosphoric acid solution of 5-10wt%.
Further, the AAO pore size of template of above-mentioned expanding treatment is 80 to 100nm, and thickness is 8 to 12 μm.
The AAO template larger in order to obtain aperture, the aperture in the embodiment of the present invention to AAO templates has been carried out at reaming
Reason.AAO pore size of template only has 30-40nm before the reaming, as shown in Figure 2；Can be reached by AAO pore size of template after reaming
80-100nm, as shown in Figure 3.By the AAO templates after expanding treatment, it is more beneficial for ferric lithium phosphate precursor slurries and enters AAO
In template.
The preparation method of AAO templates is as follows in the embodiment of the present invention：High-purity aluminium flake (purity is 99.999%) is placed in
Ultrasound 5min removals grease, rinses drying in acetone soln.The passivation layer of aluminium surface is removed using the NaOH of 5wt%, in Muffle
Made annealing treatment in stove.The use of volume ratio is 1：, used as polishing fluid, with aluminium as anode, platinum is electric for 4 perchloric acid and ethanol solution
Pole polishes 3-5min as negative electrode under 15-25V voltages.Waterproof layer is coated at the aluminium flake back side after polishing, with 0.1-5mol/L's
Oxalic acid solution is electrolyte, and 6-12h is aoxidized next time in 40-60V voltages.Mix molten with 6wt% phosphoric acid and 1.8wt% chromic acid
Liquid, immersion 1-2h removes removing oxide layer.Second oxidation, oxide layer are carried out under the same conditions.Then 5wt% phosphoric acid solutions are used
Expanding treatment is carried out to AAO templates, pore-enlargement is 0.5-4h, the AAO templates of the homogeneous arrangement of pore size are obtained.By statistics
Can obtain, pore size DHoleWith pore-enlargement tExpandSubstantially conform to following relation：DHole=30+1.2tExpand.Therefore can be by adjusting reaming
Time is obtained different pore size AAO templates.Preferred AAO templates have larger structural integrity in the embodiment of the present invention, its
Aperture is about 80nm, and thickness is about 10 μm.
Further, above-mentioned organic carbon source includes one or more in citric acid, acrylic acid, glucose.
In Surface coating conductive carbon, lithium ion diffusion in the electrodes is shortened while materials conductive rate is improved specifically,
Increase the wellability with electrolyte, while improving the electrical conductivity of LiFePO4, improve power-performance.
Further, source of iron described in the embodiment of the present invention includes the one kind in frerrous chloride, ferrous sulfate；The lithium source
Including at least one in lithium carbonate, lithium acetate, lithium nitrate or lithium hydroxide；Phosphorus source includes diammonium hydrogen phosphate, di(2-ethylhexyl)phosphate
At least one in hydrogen ammonium or phosphoric acid.Selection different material, corresponding synthesis temperature, time etc. are different.It is of the invention real
Apply dispersed homogeneous degree influence to material property of the example in view of ferric lithium phosphate precursor slurries, preferably FeCl2·4H2O is iron
Source, Li2CO3It is lithium source and H3PO4It is phosphorus source.
Further, above-mentioned ferric lithium phosphate precursor concentration of slurry is 0.05-0.2mol/L.
Ferric lithium phosphate precursor slurries are Sol-gel States, and preparation of its concentration to follow-up nano-wire array is very crucial,
In the aperture that concentration is difficult greatly very much pour into AAO templates, concentration is too small, can cause to pour into the LiFePO4 in the aperture of AAO templates
Presoma grout distribution is uneven, influences the arranged evenly of lithium iron phosphate nano linear array.
Further, above-mentioned atmosphere includes Ar gas, N of the purity more than 99.99%2Gas, Ar and N2Mixed gas, Ar with
H2Mixed gas and N2With H2Mixed gas.
Above-mentioned atmosphere is the shadow to prevent the ferrous ion in LiFePO 4 material from being aoxidized during high―temperature nuclei
Ring the thing phase purity of LiFePO4.And the generation of dephasign can directly to the performance generation harmful effect of product.
Further, the above-mentioned AAO templates for being loaded with ferric lithium phosphate precursor, sintering condition is 600- under certain atmosphere
700 DEG C of sintering 10-15h.
Under sintering condition after above-mentioned optimization, resulting LiFePO4 thing phase purity is high, good crystallinity, and what is shown is excellent
Chemical property more.
After the embodiment of the present invention vacuumizes AAO templates, ferric lithium phosphate precursor slurries are injected in template, blowing air makes
Template inner duct fills ferric lithium phosphate precursor.Then gained sample is placed in 80 DEG C of air dry ovens and dries 2-12h, repeated
Above-mentioned steps 3-5 times, until AAO templates are filled full.And under Ar atmosphere 650 DEG C heat treatment 10-15h, obtain load phosphoric acid
The AAO templates of iron lithium, as shown in figure 4, can be observed to be substantially filled with LiFePO4 in the duct of AAO templates from picture, its
Channel diameter is about 100nm, and filling is uniform.
Then conductive silver paste uniform application is being loaded into the AAO template surfaces of LiFePO4, in 100-200 DEG C of Muffle furnace
Solidification 20-40min.Prepare saturation CuCl2Solution, is added dropwise to AAO template back surfaces (without conductive silver paste face), removes template table
The Al pieces in face.The NaOH solution of 1-2mol/L is prepared, AAO template surfaces are added dropwise to, AAO templates are removed, ferric phosphate is obtained
Lithium nano-wire array, lithium iron phosphate nano linear diameter scope is 70-80nm, is evenly distributed in being parallel to each other, and is array-like structure.
The embodiment of the present invention additionally provides a kind of LiFePO 4 material, is obtained by above-mentioned preparation method, the ferric phosphate
Lithium material possesses nano-wire array pattern, and the nanowire diameter is 70 to 80nm, and the nano wire is parallel to each other, uniformly divides
Cloth.
The present invention further describes this hair by taking the lithium iron phosphate nano linear array of a specific implementation operation preparation as an example
Bright embodiment technique effect.
High-purity aluminium flake (purity is 99.999%) is placed in ultrasound 5min removals grease in acetone soln, drying is rinsed.
The passivation layer of aluminium surface is removed using the NaOH of 5wt%, is made annealing treatment in Muffle furnace.The use of volume ratio is 1：4 height
, used as polishing fluid, with aluminium as anode, platinum electrode polishes 5min as negative electrode under 18V voltages for chloric acid and ethanol solution.After polishing
Waterproof layer is coated at the aluminium flake back side, the oxalic acid solution with 0.4mol/L aoxidizes 12h next time as electrolyte in 40V voltages.With
Oxide layer in 6wt% phosphoric acid and 1.8wt% chromic acid mixed solutions.Secondary oxidation is carried out under the same conditions.After oxidation terminates
Expanding treatment is carried out to AAO templates with 5wt% phosphoric acid solutions, pore-enlargement 45min, gained AAO templates have larger structure
Regularity, its aperture is about 80nm, and thickness is about 10 μm.
With FeCl2·4H2O is source of iron, Li2CO3It is lithium source, the amount ratio of material is 1:1, it is dissolved in ethanol solution respectively,
In Li2CO3Add the H of equivalent3PO4It is phosphorus source, after magnetic agitation 3h, mixing 3h is carried out after adding equivalent citric acid, prepares
Go out ferric lithium phosphate precursor slurries.
After AAO templates are vacuumized, above-mentioned ferric lithium phosphate precursor slurries are injected in template, blowing air makes template endoporus
Fill ferric lithium phosphate precursor in road.Gained sample is placed in 80 DEG C of air dry ovens and dries 2h, repeated the above steps 5 times, made
The full AAO templates of ferric lithium phosphate precursor slurries filling.And under Ar atmosphere 650 DEG C of heat treatment 15h, obtain loading LiFePO4
AAO templates, channel diameter is about 100nm, and filling is uniform.
By conductive silver paste uniform application in the AAO template surfaces of load LiFePO4, solidify in 150 DEG C of Muffle furnaces
20min.Prepare saturation CuCl2Solution, is added dropwise to AAO template back surfaces (without conductive silver paste face), removes the Al of template surface
Piece.The NaOH solution of 1mol/L is prepared, AAO template surfaces are added dropwise to, AAO templates are removed, lithium iron phosphate nano line is obtained
Array, the lithium iron phosphate nano line is about 80nm, is evenly distributed in being parallel to each other, and is array-like structure, as shown in Figure 5.
Above-mentioned ferric lithium phosphate precursor slurries are placed in 12h is dried in 80 DEG C of air dry ovens, and 350 DEG C under Ar atmosphere
After pretreatment 4h, grinding, then 650 DEG C of heat treatment 15h obtain a nanometer LiFePO under Ar atmosphere4Particle, as shown in Figure 6.
It is electrode assembling into button cell to be coated in pole piece on aluminium foil and nano-wire array with nano particle respectively, is gone forward side by side
Row CV (cyclic voltammetric) is tested.Two kinds of pattern LiFePO4Button cell is sweeping cyclic voltammetry curve figure such as Fig. 7 of fast 0.1mV/s
It is shown.It will be seen that being that two curves occur in that two redox near 3.3V and 3.5V in voltage from figure
Peak, this just illustrates that lithium ion there occurs embedded and deviate between electrode.Electrical potential difference (△ Ep) between two peaks then indicates two
There are different degree of polarizations respectively in individual electrode.Can be obtained by calculating：LiFePO4The △ Ep of nano particle are 0.298V,
LiFePO4The △ Ep of nano-wire array are 0.176V, and the peak current density of nano-wire array is bigger.It can thus be concluded that,
LiFePO4Nano line electrode is smaller than the degree of polarization that nanoparticle electrode occurs, and the electrochemical reaction activity of generation is stronger, because
This has more preferable chemical property.
To LiFePO4The battery of nano-wire array and nano particle carries out high rate performance test, the institute of test comparison result such as 8
Show.The specific capacity that nano-wire array is measured under 0.1C, 0.5C, 1C, 5C, 10C, 20C multiplying power as seen from the figure is respectively：
156.4mAh/g, 139.5mAh/g, 132.3mAh/g, 121.8mAh/g, 106.9mAh/g, 82.1mAh/g, and nano particle
The specific capacity that nano particle is measured under identical multiplying power is respectively：156.0mAh/g、132.9mAh/g、122.3mAh/g、
111.97mAh/g, 92.0mAh/g, 72.8mAh/g, specific capacity of the nano-array under different multiplying are high than nano particle.This
Result with CV curves is consistent.It follows that nano-wire array has more preferable high rate performance.
Embodiment of the present invention Advantageous Effects：The lithium iron phosphate nano linear array that the embodiment of the present invention is prepared, is receiving
Parallel lithium ion transfer passage is formed between rice noodles, it will shorten the tortuous and distance of insertion and the abjection of lithium ion, increased
It is big to be remarkably improved active material utilization with electrolyte contacts area, high power charging-discharging is realized, current phosphoric acid can be solved
The not enough problem of the power density of iron lithium anode material.And nano wire is in addition to the advantage for possessing nano-particle, conduction has also been coated
Carbon, can eliminate interparticle contact resistance, while improve electrical conductivity and ion diffusion rates.
The preferred embodiments of the present invention are the foregoing is only, the scope of the claims of the invention, every utilization is not thereby limited
Equivalent structure or equivalent flow conversion that description of the invention and accompanying drawing content are made, or directly or indirectly it is used in other correlations
Technical field, be included within the scope of the present invention.
Claims (10)
1. a kind of lithium iron phosphate preparation method, it is characterised in that including：
Stirring is equal during the source of iron of the amount ratio of certain material, lithium source and phosphorus source are added separately into decentralized medium according to a graded
It is even, stabilization mixture is formed, then to appropriate organic carbon source is added in the stabilization mixture, dispersed with stirring is uniform, is configured to
Ferric lithium phosphate precursor slurries；
The pre-prepared AAO templates with specified pore-size distribution are put in closed container, by vacuum filtration machine by AAO templates
In air extract out, then under suction function, by the ferric lithium phosphate precursor slurries injection AAO templates hole in, and
Vacuum drying；
The AAO templates for being loaded with ferric lithium phosphate precursor after by drying are sintered under certain atmosphere, and with NaOH solution
AAO templates are removed, the LiFePO4 of nano-wire array pattern is obtained.
2. lithium iron phosphate preparation method according to claim 1, it is characterised in that in the amount ratio by certain material
Source of iron, lithium source and phosphorus source be added separately to be stirred in decentralized medium according to a graded, form stabilization mixture, then to
Appropriate organic carbon source is added in the stabilization mixture, dispersed with stirring is uniform, is configured to the step of ferric lithium phosphate precursor slurries
Before rapid, also including step：
Electrochemical polish is carried out to aluminium flake, is then aoxidized with the acid solution with oxidisability, then with weak acid mixed solution,
The oxide layer of removal oxidation generation, prepares the AAO templates.
3. lithium iron phosphate preparation method according to claim 2, it is characterised in that the condition of the electrochemical polish is：
The use of volume proportion is 1:4 perchloric acid ethanol solution is polishing fluid, and the electrochemical polish time is 3-5min, and voltage range is
15-25V；The condition of the oxidation is：Aoxidized using the oxalic acid solution with oxidisability, oxidization time is 6-12h, voltage
Scope is 40-60V, and the concentration of the oxalic acid solution is 0.1-5mol/L.
4. lithium iron phosphate preparation method according to claim 2, it is characterised in that the AAO templates are by 5-
The phosphoric acid solution of 10wt% has carried out the AAO templates of expanding treatment.
5. lithium iron phosphate preparation method according to claim 4, it is characterised in that the AAO pattern holes of the expanding treatment
Footpath is 80 to 100nm, and thickness is 8 to 12 μm.
6. lithium iron phosphate preparation method according to claim 1, it is characterised in that the organic carbon source include citric acid,
One or more in acrylic acid, glucose.
7. lithium iron phosphate preparation method according to claim 1, it is characterised in that the ferric lithium phosphate precursor slurries are dense
It is 0.05-0.2mol/L to spend.
8. lithium iron phosphate preparation method according to claim 1, it is characterised in that the atmosphere is more than including purity
99.99% Ar gas, N2Gas, Ar and N2Mixed gas, Ar and H2Mixed gas and N2With H2Mixed gas.
9. lithium iron phosphate preparation method according to claim 1, it is characterised in that the sintering condition is 600-700 DEG C
Sintering 10-15h.
10. a kind of LiFePO 4 material, it is characterised in that be obtained as the preparation method any one of claim 1 to 9,
The LiFePO 4 material possesses nano-wire array pattern, and the nanowire diameter is 70 to 80nm.
Priority Applications (1)
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| CN108751158A (en) * | 2018-05-29 | 2018-11-06 | 王子韩 | A kind of preparation method of phosphoric acid ferrisodium nano wire |
| CN109473624A (en) * | 2018-11-20 | 2019-03-15 | 贵州大学 | A kind of preparation method of collector and battery anode slice |
| CN111765908A (en) * | 2019-04-02 | 2020-10-13 | 天津大学 | Method for preparing silver nanowire embedded PDMS flexible capacitive sensor based on template method |
| CN111765911A (en) * | 2019-04-02 | 2020-10-13 | 天津大学 | Capacitive sensor with silver nanowires embedded in PDMS (polydimethylsiloxane) and treated by ozone/ultraviolet radiation |
| CN111765909A (en) * | 2019-04-02 | 2020-10-13 | 天津大学 | Method for preparing flexible capacitive sensor based on polycarbonate template method |
| CN111765910A (en) * | 2019-04-02 | 2020-10-13 | 天津大学 | Flexible capacitive sensor with silver nanowires embedded in PDMS |
| CN111765907A (en) * | 2019-04-02 | 2020-10-13 | 天津大学 | Method for preparing flexible resistance sensor based on polycarbonate template method |
| CN112038629A (en) * | 2020-09-30 | 2020-12-04 | 合肥国轩高科动力能源有限公司 | Integrated high-rate lithium iron phosphate positive electrode material and preparation method and application thereof |
| CN114914458A (en) * | 2022-06-16 | 2022-08-16 | 中国科学技术大学 | Air electrode with highly ordered array structure and preparation method thereof |
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| CN108751158A (en) * | 2018-05-29 | 2018-11-06 | 王子韩 | A kind of preparation method of phosphoric acid ferrisodium nano wire |
| CN109473624A (en) * | 2018-11-20 | 2019-03-15 | 贵州大学 | A kind of preparation method of collector and battery anode slice |
| CN111765908A (en) * | 2019-04-02 | 2020-10-13 | 天津大学 | Method for preparing silver nanowire embedded PDMS flexible capacitive sensor based on template method |
| CN111765911A (en) * | 2019-04-02 | 2020-10-13 | 天津大学 | Capacitive sensor with silver nanowires embedded in PDMS (polydimethylsiloxane) and treated by ozone/ultraviolet radiation |
| CN111765909A (en) * | 2019-04-02 | 2020-10-13 | 天津大学 | Method for preparing flexible capacitive sensor based on polycarbonate template method |
| CN111765910A (en) * | 2019-04-02 | 2020-10-13 | 天津大学 | Flexible capacitive sensor with silver nanowires embedded in PDMS |
| CN111765907A (en) * | 2019-04-02 | 2020-10-13 | 天津大学 | Method for preparing flexible resistance sensor based on polycarbonate template method |
| CN112038629A (en) * | 2020-09-30 | 2020-12-04 | 合肥国轩高科动力能源有限公司 | Integrated high-rate lithium iron phosphate positive electrode material and preparation method and application thereof |
| CN112038629B (en) * | 2020-09-30 | 2022-07-05 | 合肥国轩高科动力能源有限公司 | Integrated high-rate lithium iron phosphate positive electrode material and preparation method and application thereof |
| CN114914458A (en) * | 2022-06-16 | 2022-08-16 | 中国科学技术大学 | Air electrode with highly ordered array structure and preparation method thereof |
| CN114914458B (en) * | 2022-06-16 | 2024-01-05 | 中国科学技术大学 | Air electrode with highly ordered array structure and preparation method thereof |
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