CN103236544A - Method for preparing cathode material of lithium iron phosphate without coating of pole piece - Google Patents

Method for preparing cathode material of lithium iron phosphate without coating of pole piece Download PDF

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Publication number
CN103236544A
CN103236544A CN2013101703103A CN201310170310A CN103236544A CN 103236544 A CN103236544 A CN 103236544A CN 2013101703103 A CN2013101703103 A CN 2013101703103A CN 201310170310 A CN201310170310 A CN 201310170310A CN 103236544 A CN103236544 A CN 103236544A
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iron phosphate
pole piece
lithium iron
electrostatic spinning
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张长欢
梁银峥
孙世元
邱夷平
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Donghua University
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Donghua University
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Abstract

The invention relates to a method for preparing a cathode material of lithium iron phosphate without coating of a pole piece. The method comprises the following steps of: adding 0.1 to 0.4 mass percent of carbon nano tube (CNT) into 83.6 to 83.9 mass percent of solvent; performing ultrasonic oscillation for 4 to 6 hours; stirring for 15 to 18 hours; adding 8 mass percent of LiCOOCH3, Fe(COOCH3)2 and H3PO4, and magnetically stirring for 12 to 15 hours; adding 8 mass percent of polyacrylonitrile (PAN) powder, and magnetically stirring for 12 to 24 hours to obtain a solution for electrostatic spinning; electrostatically spinning to obtain an electrostatic spinning fiber felt; and drying, and sintering at high temperature to obtain the cathode material of the lithium iron phosphate. The the cathode material of the lithium iron phosphate is high in purity and high in processing performance, and microtopography, physical and chemical performances as well as electrochemical performance are greatly improved. The method has the characteristics of high material film-forming property and high processing performance; the influence on the performance of a battery caused by the coating of the pole piece in the existing battery production is eliminated; the cost is reduced; and the performance of the battery is improved.

Description

A kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece
Technical field
The invention belongs to the preparation field of LiFePO 4 material, particularly a kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece.
Background technology
Increasingly sharpening of the environmental pollution that faces along with the whole world and problem of energy crisis; the energy green, efficient, cleaning more and more is subjected to people's favor; therefore; the energy storage technology particularly exploitation of green energy resource is extremely urgent, and chemical power sources such as Ni-MH battery, nickel-cadmium cell, lithium ion battery, fuel cell, solar cell just become one of developing direction of green energy resource.
Lithium ion battery is as the new generation of green power supply, be hopeful most to replace traditional storage battery and be used for novel electric vehicle, and electric automobile need be equipped with large-sized battery, and present lithium-ion electric pool technology can not satisfy this requirement, and one of the main reasons is that positive electrode can not satisfy the high-power requirement that discharges and recharges.
Commercial LiCoO 2, LiNiO 2At high temperature there is potential safety hazard Deng anode material for lithium-ion batteries, and polyanion type LiFePO 4 material has Stability Analysis of Structures, theoretical capacity height, has extended cycle life, Environmental compatibility is good, raw material resources is abundant, series of advantages such as cheap, particularly its olivine structural more makes it to have possessed good cycle and the high advantage of stability, therefore, it is acknowledged as the anode material for lithium-ion batteries of new generation of the tool development and application potentiality in the electric automobile field.
Electronic conductivity and the ionic conductance of the iron phosphate lithium positive pole dusty material that is prepared from traditional carbothermic method and high temperature solid-state method etc. are lower, Li +Diffusion coefficient less, be not suitable for high current charge-discharge, in addition, also to solve processing technology when applying anode slice of lithium ion battery to Effect on Performance, hindered its large-scale application in electrokinetic cell.There are some researches show, can improve the performance of LiFePO 4 material by nanometer, surface carbon coating and method of modifying such as Graphene, metal ion mixing, but, to realize successfully that commercialization also will solve the raising of the cost that material nanoization brings, also there are some researches show, add follow-up high-sintering process by electrostatic spinning in conjunction with sol-gel technique and can prepare carbon-coated LiFePO 4 for lithium ion batteries (LiFePO 4/ C) membrane material, still, the uniformity of the fiber of material and consistency, and film forming all has much room for improvement.Therefore, the technology of preparing of lithium iron phosphate positive material is very crucial.
(Ozan, Liwen Ji, Zhan Lin.196 (2011): 7692-7699) with LiCOOCH such as Toprakci 3, Fe (COOCH 3) 2, H 3PO 4With PAN be raw material, utilize electrostatic spinning to add follow-up high temperature sintering in conjunction with sol-gel technique and prepared LiFePO 4/ C cathode film material, the discharge capacity under 0.1C is 141mAh/g.Toprakci etc. (Toprakci O., Toprakci H.A.K., JiL.4 (1) (2012)) are with LiFePO 4Nano particle, PAN and Graphene are raw material, have prepared the LiFePO with better electrochemical performance 4/ Graphene/C cathode film material.But, they do not study the adding of CNT to the influence of membrane material characteristic, and electrostatic spinning fiber felt and the fibrofelt of their preparation are all relatively poor through the microscopic appearance behind the high temperature sintering, uniformity and the consistency of fiber all have much room for improvement, beading and slubbing are also apparent in view, and they do not study heating rate, temperature retention time and the air flow property etc. in pre-oxidation stage to the final Effect on Performance of film forming, processing characteristics and product of material yet.
Summary of the invention
Technical problem to be solved by this invention provides a kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece, this method is with low cost, method of operation is simple, and the material of preparation has better machining property and chemical property, is fit to large-scale industrial production.
A kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece of the present invention comprises:
By mass percentage, with the carbon nano-tube CNT of 0.1-0.4%, join in the solvent of 83.6-83.9%, sonic oscillation, 4-6h stirs 15-18h, adds 8% LiCOOCH then 3, Fe (COOCH 3) 2And H 3PO 4, magnetic agitation 12-15h adds 8% polyacrylonitrile powder, and magnetic agitation 12-24h obtains electrostatic spinning solution, carries out electrostatic spinning, gets the electrospun fibers felt, drying, high temperature sintering namely gets the LiFePO of Nano grade 4/ C+CNT composite positive pole, wherein LiCOOCH 3, Fe (COOCH 3) 2And H 3PO 4The mol ratio of middle Li, Fe, P is 1:1:1.
Described solvent is N, dinethylformamide DMF.
Described electrostatic spinning process parameter is: the syringe needle internal diameter of syringe is 0.51mm, spinning voltage is 23kv, and syringe needle is 15cm apart from the distance of dash receiver, and injection speed is 0.7-1ml/h, the electrostatic spinning ambient temperature is 20-30 ° of C, and the electrostatic spinning envionmental humidity is 30-40%.
The addition of described carbon nano-tube CNT is 0.2% of gross mass, and the syringe needle internal diameter of syringe is 0.51mm, and spinning voltage is 23kv, and syringe needle is 15cm apart from the distance of dash receiver, and the electrostatic spinning injection speed is set at 1ml/h.
Described drying is: drying 2-4h in vacuum drying oven, and vacuum is evacuated to 0.9Pa, and temperature remains on 50 degree.
Described high temperature sintering comprises pre-oxidation and charing.
The program of described pre-oxidation is: under air atmosphere, speed with 2 ° of C/min rises to 100 ° of C insulation 20min from room temperature, speed with 2 ° of C/min is warming up to 280 ° of C from 100 ° of C again, insulation 2-4h, when temperature rises to 140-160 ° of C, begin to feed moving air, to 280 ° of C insulation 0.5h, finish; The charing program is: under the argon gas that flows or protection of nitrogen gas; speed with 2 ° of C/min is warming up to 700 ° of C from 280 ° of C; insulation 16h; the flow velocity of argon gas or nitrogen is 300-500ml/min; after reaction finishes; be under the argon gas or nitrogen protection of 300-500ml/min at flow velocity, be cooled to room temperature naturally.
Described feeding moving air is that vacuum pump is opened 5-10min earlier, close 5-10min again, or vacuum pump is opened always.
The temperature retention time of described pre-oxidation is 3h, and temperature begins to feed moving air when rising to 140 ° of C.
Describedly open feeding vacuum pump described in the moving air process always.
The method that the present invention proposes to utilize electrostatic spinning technique and high temperature sintering technology to combine prepares a kind of highly purified membrane material that is easy to suppress pole piece, need not to apply pole piece, can directly suppress the LiFePO of the Nano grade of use 4/ C+CNT composite positive pole.Electrostatic spinning technique can prepare the positive level material of lithium ion battery of Nano grade, and its preparation technology is simple, flow process short, for anode material for lithium ion battery has been opened up new research approach; The doping of carbon nano-tube has increased its inner proton conductivity, thereby has improved its cycle performance; And high-sintering process is a kind of procedure of material.Wherein, the humiture of the setting of the ratio of the used solution of electrostatic spinning, electrostatic spinning parameter and electrostatic spinning environment all directly influences pattern and the performance of electrostatic spinning fiber, and then influence the performance of electrostatic spinning fiber felt, and have influence on the chemical property of final products; During high temperature sintering, the film forming of determining directly to influence material of pre-oxidation process, and then play direct and significant effects to the processing characteristics of pole piece and the chemical property of final products.
Beneficial effect
(1) preparation method of the present invention is simple, has reduced cost, is fit to large-scale industrial production;
(2) the present invention effectively raises LiFePO 4The uniformity of/C+CNT composite fibre and consistency have reduced granular sensation;
(3) pre-oxidation process of the present invention's employing, effectively raise the film forming behind the electrostatic spinning nano fiber felt sintering, the micro/nano fibrous membrane material that obtains is easy to carry out the compacting of pole piece, has better machining property, do not need to use the adhesive bonding just to can be used as electrode material and directly use, have better electrochemical performance;
(4) the present invention has the good film-forming property of material, and the characteristics of good processability had both overcome pole piece in the existing battery production and applied influence to battery performance, had reduced cost, had also improved the performance of battery;
(5) the present invention is with electrostatic spinning technique, high temperature sintering technology, the carbon fiber LiFePO for preparing Nano grade that combines such as compound, carbon nano tube-doped 4/ C+CNT composite positive pole, both increased the contact area of active particle and electrolyte, increased the diffusion admittance of conductivity of electrolyte materials and lithium ion again, thereby improved the electrical conductance of material, charge and discharge capacity and cycle performance, promote the preparation method's of electrode material for lithium ion cell breakthrough formula innovation, can break through the bottleneck that runs in the present anode material for lithium-ion batteries application.
Description of drawings
Fig. 1 is the SEM collection of illustrative plates of the electrostatic spinning fiber felt of preparation such as Toprakci;
Fig. 2 is the later LiFePO of sintering of preparation such as Toprakci 4The SEM collection of illustrative plates of/C membrane material;
Fig. 3 is 1000 times SEM collection of illustrative plates of the electrospun fibers felt of the embodiment of the invention 1 preparation;
Fig. 4 is 1000 times SEM collection of illustrative plates of the electrospun fibers felt of the embodiment of the invention 2 preparations;
Fig. 5 is 5000 times SEM collection of illustrative plates of the electrospun fibers felt of the embodiment of the invention 2 preparations;
Fig. 6 is the LiFePO of the Nano grade of the embodiment of the invention 4 preparations 41000 times SEM collection of illustrative plates of/C+CNT composite positive pole;
Fig. 7 is the LiFePO of the Nano grade of the embodiment of the invention 4 preparations 45000 times SEM collection of illustrative plates of/C+CNT composite positive pole;
Fig. 8 is the LiFePO of the Nano grade of the embodiment of the invention 4 preparations 4The XRD diffracting spectrum of/C+CNT composite positive pole;
Fig. 9 is the LiFePO of the Nano grade of the embodiment of the invention 4 preparations 4The first discharge capacity curve of button half-cell under 0.5C of/C+CNT composite positive pole assembling.
Embodiment
Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiment only to be used for explanation the present invention and be not used in and limit the scope of the invention.Should be understood that in addition those skilled in the art can make various changes or modifications the present invention after the content of having read the present invention's instruction, these equivalent form of values fall within the application's appended claims institute restricted portion equally.
Embodiment 1
1) get the CNT of gross mass 0.1-0.4% earlier, join in the DMF solution of gross mass 83.6-83.9%, sonic oscillation 4-6h, magnetic agitation 15-18h is that the mol ratio of 1:1:1 is got the LiCOOCH of gross mass 8% respectively according to Li:Fe:P then 3, Fe (COOCH 3) 2And H 3PO 4, join magnetic agitation 12-15h in the above-mentioned mixed liquor, get the PAN powder of gross mass 8% at last, join magnetic agitation 12-24h in the above-mentioned mixed liquor, thus the electrostatic spinning solution that is fully mixed.
2) electrostatic spinning is put into syringe with solution and carry out electrostatic spinning, the syringe needle internal diameter of syringe is 0.51mm, spinning voltage is 23kv, syringe needle is 15cm apart from the distance of dash receiver, injection speed is 0.7-1ml/h, the electrostatic spinning ambient temperature is 20-30 ° of C, and the electrostatic spinning envionmental humidity is 30-40%, obtains the electrospun fibers felt.
3) the electrospun fibers felt is put into vacuum drying oven drying 2-4h, vacuum is evacuated to 0.9Pa, and temperature remains on 50 degree.
4) the electrospun fibers felt behind the drying is put into the box atmosphere furnace that can vacuumize and can feed argon gas or nitrogen and carries out high temperature sintering---pre-oxidation and charing, the program of pre-oxidation is as follows: under air atmosphere, speed with 2 ° of C/min rises to 100 ° of C insulation 20min from room temperature, speed with 2 ° of C/min is warming up to 280 ° of C from 100 ° of C again, insulation 2-4h, when temperature rises to 140-160 ° of C, begin to feed moving air, to 280 ° of C insulation 0.5h, finish; The program of charing is as follows: under the argon gas that flows or protection of nitrogen gas; speed with 2 ° of C/min is warming up to 700 ° of C from 280 ° of C; insulation 16h; the flow velocity of argon gas or nitrogen is 300-500ml/min; after reaction finishes; be under the argon gas or nitrogen protection of 300-500ml/min at flow velocity, be cooled to room temperature naturally, compacting obtains the LiFePO of Nano grade 4/ C+CNT composite positive pole.
Above-mentioned steps 4) the feeding moving air described in is that vacuum pump is opened 5-10min earlier, closes 5-10min again, and perhaps vacuum pump is opened always.
Embodiment 2
1) get the CNT of gross mass 0.2% earlier, join in the DMF solution of gross mass 83.8%, sonic oscillation 6h, magnetic agitation 18h is that the mol ratio of 1:1:1 is got the LiCOOCH of gross mass 8% respectively according to Li:Fe:P then 3, Fe (COOCH 3) 2And H 3PO 4, join magnetic agitation 12h in the above-mentioned mixed liquor, get the PAN powder of gross mass 8% at last, join magnetic agitation 12-24h in the above-mentioned mixed liquor, thus the electrostatic spinning solution that is fully mixed.
2) electrostatic spinning is put into syringe with solution and carry out electrostatic spinning, the syringe needle internal diameter of syringe is 0.51mm, spinning voltage is 23kv, syringe needle is 15cm apart from the distance of dash receiver, injection speed is 1ml/h, the electrostatic spinning ambient temperature is 20-30 ° of C, and the electrostatic spinning envionmental humidity is 30-40%, obtains the electrospun fibers felt.
3) the electrospun fibers felt is put into vacuum drying oven drying 2-4h, vacuum is evacuated to 0.9Pa, and temperature remains on 50 degree.
4) the electrospun fibers felt behind the drying is put into the box atmosphere furnace that can vacuumize and can feed argon gas or nitrogen and carries out high temperature sintering---pre-oxidation and charing, the program of pre-oxidation is as follows: under air atmosphere, speed with 2 ° of C/min rises to 100 ° of C insulation 20min from room temperature, speed with 2 ° of C/min is warming up to 280 ° of C from 100 ° of C again, insulation 2-4h, when temperature rises to 140-160 ° of C, begin to feed moving air, to 280 ° of C insulation 0.5h, finish; The program of charing is as follows: under the argon gas that flows or protection of nitrogen gas; speed with 2 ° of C/min is warming up to 700 ° of C from 280 ° of C; insulation 16h; the flow velocity of argon gas or nitrogen is 300-500ml/min; after reaction finishes; be under the argon gas or nitrogen protection of 300-500ml/min at flow velocity, be cooled to room temperature naturally, compacting obtains the LiFePO of Nano grade 4/ C+CNT composite positive pole.
Above-mentioned steps 4) the feeding moving air described in is that vacuum pump is opened 5-10min earlier, closes 5-10min again, and perhaps vacuum pump is opened always.
Embodiment 3
1) get the CNT of gross mass 0.2% earlier, join in the DMF solution of gross mass 83.8%, sonic oscillation 6h, magnetic agitation 18h is that the mol ratio of 1:1:1 is got the LiCOOCH of gross mass 8% respectively according to Li:Fe:P then 3, Fe (COOCH 3) 2And H 3PO 4, join magnetic agitation 12h in the above-mentioned mixed liquor, get the PAN powder of gross mass 8% at last, join magnetic agitation 12-24h in the above-mentioned mixed liquor, thus the electrostatic spinning solution that is fully mixed.
2) electrostatic spinning is put into syringe with solution and carry out electrostatic spinning, the syringe needle internal diameter of syringe is 0.51mm, spinning voltage is 23kv, syringe needle is 15cm apart from the distance of dash receiver, injection speed is 1ml/h, the electrostatic spinning ambient temperature is 20-30 ° of C, and the electrostatic spinning envionmental humidity is 30-40%, obtains the electrospun fibers felt.
3) the electrospun fibers felt is put into vacuum drying oven drying 2h, vacuum is evacuated to 0.9Pa, and temperature remains on 50 degree.
4) the electrospun fibers felt behind the drying is put into the box atmosphere furnace that can vacuumize and can feed argon gas or nitrogen and carries out high temperature sintering---pre-oxidation and charing, the program of pre-oxidation is as follows: under air atmosphere, speed with 2 ° of C/min rises to 100 ° of C insulation 20min from room temperature, speed with 2 ° of C/min is warming up to 280 ° of C from 100 ° of C again, insulation 3h, when temperature rises to 140 ° of C, begin to feed moving air, to 280 ° of C insulation 0.5h, finish; The program of charing is as follows: under the argon gas that flows or protection of nitrogen gas; speed with 2 ° of C/min is warming up to 700 ° of C from 280 ° of C; insulation 16h; the flow velocity of argon gas or nitrogen is 300-500ml/min; after reaction finishes; be under the argon gas or nitrogen protection of 300-500ml/min at flow velocity, be cooled to room temperature naturally, compacting obtains the LiFePO of Nano grade 4/ C+CNT composite positive pole.
Above-mentioned steps 4) the feeding moving air described in is that vacuum pump is opened 5-10min earlier, closes 5-10min again, and perhaps vacuum pump is opened always.
Embodiment 4
1) get the CNT of gross mass 0.2% earlier, join in the DMF solution of gross mass 83.8%, sonic oscillation 6h, magnetic agitation 18h is that the mol ratio of 1:1:1 is got the LiCOOCH of gross mass 8% respectively according to Li:Fe:P then 3, Fe (COOCH 3) 2And H 3PO 4, join magnetic agitation 12h in the above-mentioned mixed liquor, get the PAN powder of gross mass 8% at last, join magnetic agitation 12-24h in the above-mentioned mixed liquor, thus the electrostatic spinning solution that is fully mixed.
2) electrostatic spinning is put into syringe with solution and carry out electrostatic spinning, the syringe needle internal diameter of syringe is 0.51mm, spinning voltage is 23kv, syringe needle is 15cm apart from the distance of dash receiver, injection speed is 1ml/h, the electrostatic spinning ambient temperature is 20-30 ° of C, and the electrostatic spinning envionmental humidity is 30-40%, obtains the electrospun fibers felt.
3) the electrospun fibers felt is put into vacuum drying oven drying 2h, vacuum is evacuated to 0.9Pa, and temperature remains on 50 degree.
4) the electrospun fibers felt behind the drying is put into the box atmosphere furnace that can vacuumize and can feed argon gas or nitrogen and carries out high temperature sintering---pre-oxidation and charing, the program of pre-oxidation is as follows: under air atmosphere, speed with 2 ° of C/min rises to 100 ° of C insulation 20min from room temperature, speed with 2 ° of C/min is warming up to 280 ° of C from 100 ° of C again, insulation 3h, when temperature rises to 140 ° of C, begin to feed moving air, to 280 ° of C insulation 0.5h, finish; The program of charing is as follows: under the argon gas that flows or protection of nitrogen gas; speed with 2 ° of C/min is warming up to 700 ° of C from 280 ° of C; insulation 16h; the flow velocity of argon gas or nitrogen is 300-500ml/min; after reaction finishes; be under the argon gas or nitrogen protection of 300-500ml/min at flow velocity, be cooled to room temperature naturally, compacting obtains the LiFePO of Nano grade 4/ C+CNT composite positive pole.
Above-mentioned steps 4) the feeding moving air described in is that vacuum pump is opened always.
In order to verify the validity of above technical scheme, the present invention has carried out following test and analysis.
1, microscopic appearance analysis
Fig. 1 and Fig. 2 are respectively electrostatic spinning fiber felt and the later LiFePO of sintering of preparation such as Toprakci 4The SEM collection of illustrative plates of/C membrane material.As can be seen from the figure, beading and the slubbing of static woven material are apparent in view, and the uniformity of fiber and consistency are relatively poor, the LiFePO that sintering is later 4The plucked of the fiber of/C membrane material is more obvious, and granular sensation increases a lot.
Fig. 3 is 1000 times SEM collection of illustrative plates of the electrospun fibers felt of the embodiment of the invention 1 preparation, and Fig. 4 and Fig. 5 are respectively 1000 times and 5000 times SEM collection of illustrative plates of the electrospun fibers felt of the embodiment of the invention 2 preparations.As can be seen from the figure, fiber uniformity and the consistency of electrostatic spinning fiber felt are better, and do not have beading and slubbing substantially, and the adhesive between the fiber is also little, when the addition of CNT is 0.2% of gross mass, the syringe needle internal diameter of syringe is 0.51mm, and spinning voltage is 23kv, and syringe needle is 15cm apart from the distance of dash receiver, the electrostatic spinning injection speed is set at 1ml/h, the electrostatic spinning ambient temperature is 20-30 ° of C, and the electrostatic spinning envionmental humidity is 30-40%, and the microscopic appearance of fiber is best.
Fig. 6 and Fig. 7 are respectively the LiFePO of the Nano grade of the embodiment of the invention 4 preparations 41000 times and 5000 times SEM collection of illustrative plates of/C+CNT composite positive pole.As can be seen from the figure, the electrospun fibers felt of present embodiment preparation is behind oversintering, and fiber has shrinkage crimping and variation in diameter, and the fiber inhomogeneity has increase slightly, but the beading of fiber are relative with slubbing less, and granular sensation is less.
2, crystal structure and thing phase composition are analyzed
Fig. 8 is the LiFePO of the Nano grade of the embodiment of the invention 4 preparations 4The XRD diffracting spectrum of/C+CNT composite positive pole, as can be seen from the figure, the position at principal character peak is corresponding good with the standard card of LiFePO4 diffraction pattern, proves the LiFePO4 with complete olivine structural.The diffracted intensity of peak value correspondence is also bigger, proves that the crystalline condition of product is good.
3, electrochemical property test
In order to test chemical property, adopt the LiFePO of the Nano grade of the present invention's preparation 4/ C+CNT composite positive pole has been assembled the button half-cell, and carries out the first all charge-discharge tests under the 0.5C, and the discharge capacity in the first week under 0.5C reaches 140mAh/g~150mAh/g, and discharge platform is that discharge platform is smooth about 3.4V.
When the addition of CNT 0.2% the time, the discharge capacity of material is relatively large; The temperature retention time in pre-oxidation stage is when 3h, guaranteed that raw material is when fully reacting, avoid the unnecessary prolongation of sintering time and make material that a spot of unnecessary ablation be arranged, so that drawing abillity there is decline slightly, and then influence the chemical property of material; When the pre-oxidation phase temperature rose to 140 ° of C, the unlatching vacuum pump cut out vacuum pump after feeding atmosphere to the 280 ° C insulation 0.5h that flows, and is easy to the compacting of pole piece most.
Fig. 9 is the LiFePO of the Nano grade of the embodiment of the invention 4 preparations 4The button half-cell of/C+CNT composite positive pole assembling, the first all discharge capacities under the 0.5C test, as can be seen from the figure, the discharge capacity of material is 150mAh/g, discharge platform is that discharge platform is smooth about 3.4V.Adopt the LiFePO of present embodiment preparation 4The button half-cell chemical property of/C+CNT positive electrode assembling is good.

Claims (10)

1. preparation method who need not to apply the lithium iron phosphate positive material of pole piece comprises:
By mass percentage, with the carbon nano-tube CNT of 0.1-0.4%, join in the solvent of 83.6-83.9%, sonic oscillation, 4-6h stirs 15-18h, adds 8% LiCOOCH then 3, Fe (COOCH 3) 2And H 3PO 4, magnetic agitation 12-15h adds 8% polyacrylonitrile powder, and magnetic agitation 12-24h obtains electrostatic spinning solution, carries out electrostatic spinning, gets the electrospun fibers felt, drying, high temperature sintering namely gets the LiFePO of Nano grade 4/ C+CNT composite positive pole, wherein LiCOOCH 3, Fe (COOCH 3) 2And H 3PO 4The mol ratio of middle Li, Fe, P is 1:1:1.
2. a kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece according to claim 1, it is characterized in that: described solvent is N, dinethylformamide DMF.
3. a kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece according to claim 1, it is characterized in that: described electrostatic spinning process parameter is: the syringe needle internal diameter of syringe is 0.51mm, spinning voltage is 23kv, syringe needle is 15cm apart from the distance of dash receiver, and injection speed is 0.7-1ml/h.
4. a kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece according to claim 1, it is characterized in that: the addition of described carbon nano-tube CNT is 0.2% of gross mass, the syringe needle internal diameter of syringe is 0.51mm, spinning voltage is 23kv, syringe needle is 15cm apart from the distance of dash receiver, the electrostatic spinning injection speed is set at 1ml/h, and the electrostatic spinning ambient temperature is 20-30 ° of C, and the electrostatic spinning envionmental humidity is 30-40%.
5. a kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece according to claim 1, it is characterized in that: described drying is: drying 2-4h in vacuum drying oven, vacuum is evacuated to 0.9Pa, and temperature remains on 50 degree.
6. a kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece according to claim 1, it is characterized in that: described high temperature sintering comprises pre-oxidation and charing.
7. a kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece according to claim 6, it is characterized in that: the program of described pre-oxidation is: under air atmosphere, speed with 2 ° of C/min rises to 100 ° of C insulation 20min from room temperature, speed with 2 ° of C/min is warming up to 280 ° of C from 100 ° of C again, insulation 2-4h, when temperature rises to 140-160 ° of C, begin to feed moving air, to 280 ° of C insulation 0.5h, finish; The charing program is: under the argon gas that flows or protection of nitrogen gas; speed with 2 ° of C/min is warming up to 700 ° of C from 280 ° of C; insulation 16h; the flow velocity of argon gas or nitrogen is 300-500ml/min; after reaction finishes; be under the argon gas or nitrogen protection of 300-500ml/min at flow velocity, be cooled to room temperature naturally.
8. a kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece according to claim 7, it is characterized in that: described feeding moving air is that vacuum pump is opened 5-10min earlier, close 5-10min again, or vacuum pump is opened always.
9. a kind of preparation method who need not to apply the lithium iron phosphate positive material of pole piece according to claim 7, it is characterized in that: the temperature retention time of described pre-oxidation is 3h, and temperature begins to feed moving air when rising to 140 ° of C.
10. according to claim 7 and 9 described a kind of preparation methods that need not to apply the lithium iron phosphate positive material of pole piece, it is characterized in that: describedly open feeding vacuum pump described in the moving air process always.
CN2013101703103A 2013-05-09 2013-05-09 Method for preparing cathode material of lithium iron phosphate without coating of pole piece Pending CN103236544A (en)

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Cited By (6)

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CN105098179A (en) * 2014-05-20 2015-11-25 北京理工大学 Preparation method of sodium-ion battery cathode material Na3V2(PO4)3
CN108574099A (en) * 2018-06-11 2018-09-25 河南电池研究院有限公司 A kind of preparation method of lithium ion battery composite cathode material
CN108807946A (en) * 2018-08-07 2018-11-13 许焕生 The preparation method of anode material of lithium battery with multi-layer core-shell structure
CN111900411A (en) * 2020-08-14 2020-11-06 四川轻化工大学 Self-supporting silicon-carbon negative electrode material and preparation method thereof

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Cited By (8)

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Publication number Priority date Publication date Assignee Title
CN103872287A (en) * 2014-03-20 2014-06-18 重庆工商大学 Composite positive electrode material of graphene and lithium iron phosphate battery and preparation method thereof
CN105098179A (en) * 2014-05-20 2015-11-25 北京理工大学 Preparation method of sodium-ion battery cathode material Na3V2(PO4)3
CN105098179B (en) * 2014-05-20 2017-08-25 北京理工大学 A kind of preparation method of sodium-ion battery positive material Na3V2 (PO4) 3
CN104466106A (en) * 2014-12-02 2015-03-25 长沙矿冶研究院有限责任公司 Coaxial cable type metal-based phosphate composite fiber cathode material as well as preparation method and application thereof
CN104466106B (en) * 2014-12-02 2016-11-30 长沙矿冶研究院有限责任公司 Coaxial cable type Metal Substrate phosphate-based composite fibre positive electrode and its preparation method and application
CN108574099A (en) * 2018-06-11 2018-09-25 河南电池研究院有限公司 A kind of preparation method of lithium ion battery composite cathode material
CN108807946A (en) * 2018-08-07 2018-11-13 许焕生 The preparation method of anode material of lithium battery with multi-layer core-shell structure
CN111900411A (en) * 2020-08-14 2020-11-06 四川轻化工大学 Self-supporting silicon-carbon negative electrode material and preparation method thereof

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