CN101315981B - Lithium iron phosphate anode material for lithium ion battery and modification method - Google Patents
Lithium iron phosphate anode material for lithium ion battery and modification method Download PDFInfo
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Abstract
The invention provides a lithium iron phosphate anode material used for lithium ion batteries; the lithium iron phosphate which is prepared by a water heating method is taken as a precursor which is then uniformly mixed with a conductive matter precursor and metal ion salt, and finally baked in inert gas to obtain the lithium iron phosphate anode material which is coated by the conductive matter and doped by the metal ions. Compared with a pure solid phase reaction method, the method of the invention has small energy dissipation, the chemical uniformity of the synchronized outcome is good, the dimension and the appearance of the outcome are uniform, and the electromechanical performance and the processing performance have good stability and repeatability. Compared with the a pure water heating method, as the coating of the conductive matter, the doping and modifying performance of the metal ions are added during the anaphase, the electric conductivity of the material is greatly improved, and the high magnification electromechanical performance of the material is excellent; wherein, under the 10C discharging magnification, the discharging content of the lithium iron phosphate anode material with the copper ion doped is kept at 107mAh/g. After circulation for 50 times, the discharging content of the material is kept unchangeable basically, which can certify that the material has good circulation performance.
Description
One, technical field
The invention belongs to the electrochemical power source technical field of material, relate to a kind of lithium ion battery ferrous lithium anode material of modified phosphate and method of modifying thereof.
Two, background technology
20th century were to be the society of power with gasoline.Yet the limited reserves of oil and the pollution that automobile causes are the problems that faces solution 21 century, have caused widely to pay close attention to.Develop alternative energy source energetically and can fundamentally solve top problem.Thereby motive force of development battery is the key measure that addresses this problem, and at present, generally the secondary cell of Shi Yonging has 4 kinds: lead-acid battery, nickel-cadmium cell, Ni-MH battery and lithium ion battery.Though the lead-acid battery low price, specific capacity is little, and the stroke that once charges is short, and it is few to discharge and recharge number of times, and useful life is short, and battery is heavier.Nickel-cadmium cell belongs to alkaline battery, and memory effect is arranged, and cadmium is strong carcinogen, and environmental pollution is more serious, just is being subjected to the challenge of emerging battery.Ni-MH battery also belongs to alkaline battery, and certain memory effect is also arranged, and high rate during charging-discharging is undesirable, and self discharge is higher.Thereby, remove price factor, lithium ion battery is big with its specific capacity, specific power and cycle life, and self discharge seldom waits advantage to become the first-selection of electrokinetic cell.
Positive electrode is the important component part of lithium ion battery.At present, the maximum positive electrode of research is LiCoO
2, LiNiO
2, LiMn
2O
4LiCoO
2Be the positive electrode of unique large-scale commercial, but have cost an arm and a leg, unfriendly and to environment as shortcoming such as the fail safe of electrokinetic cell is relatively poor.LiNiO
2The preparation condition harshness, the cycle performance and the thermal stability of material are poor.And the LiMn of spinel structure
2O
4Mn in Jahn-Teller effect that when deep discharge, takes place and the charge and discharge process
3+Dissolving, particularly the cycle performance of material under hot conditions is poor to cause the cycle performance of material, has also limited the application of this material in electrokinetic cell.People such as U.S. A.K.Padhi successfully synthesized LiFePO in 1997
4, by extensive studies, particularly the performance of its overcharging resisting of having becomes it and is applied to the most promising positive electrode of electrokinetic cell characteristics such as price is low because of having for this material, Heat stability is good, theoretical capacity height and good cycle as positive electrode.
LiFePO
4Have olivine structural, its theoretical capacity is 170mAh/g, and discharge platform is 3.4V.PO in its crystal structure
4 3-Have good thermal stability, can stop the decomposition of oxygen in the high temperature lower electrode material effectively, make ferrousphosphate lithium material have the excellent security energy.Charge/discharge capacity is less down at big electric current (high magnification) and the low electric conductivity that this structure causes makes ferrous phosphate lithium battery.A large amount of LiFePO 4 modification work has been done by many for this reason research institutions and company, so that improve the lithium ion diffusion coefficient and the electronic conductivity of this material, and finally improves the high rate capability of LiFePO 4.The disclosed patent of Xianxing Science-Technology-Industry Co Ltd, Beijing Univ (application number: 200410039176.4) report, adopt the synthetic LiFePO of solid reaction process
4The time, add various organic additive, by their cracking, be decomposed into the good LiFePO of electric conductivity
4Material.When being additive with glucose, the material that synthesizes is at 2mA/cm
2Current discharge, its capacity is 140mAh/g, when with 11.432mA/cm
2Current discharge, its capacity is 120mAh/g.(application number: 200410018476.4) report evenly mixes the phosphate of the metal iron powder of certain proportioning, lithium phosphate, doped chemical and conductive agent or conductive agent presoma the disclosed patent of professor Ma Zifeng of Shanghai Communications University, behind ball milling, calcine, prepare the ferrous phosphate lithium powder of ferrous phosphate lithium powder and doping, product is charge-discharge test under the 1C multiplying power, and its discharge capacity is 138mAh/g.Chung and partner thereof (Electronically conductive phospho-olivines as lithium storage electrodes[J] .Nature Materials, 2002,1,123-128.) with high volence metal ion (Nb
5+, Ti
4+, W
6+Deng) alkoxide be dopant, synthesized LiFePO with cation defect
4, it is said that conductance has improved 8 orders of magnitude, when charging with current density 315mA/g, material capacity is 110mAh/g; When charging with 3225mA/g, material specific capacity is 60mAh/g.
In addition, (Characterization of LiFePO such as Takahashi
4As the cathode material for rechargeablelithium batteries[J] .Journal of Power Sources, 2001,97-98:508-511.) prepare LiFePO with solid phase method
4, comparative study the LiFePO for preparing under the different heating temperature
4The relation of particle size and chemical property.At 675 ℃ of LiFePO that prepare down
4Particle is tiny, and material surface is more coarse, at 0.5mA/cm
2Current density under discharge, capacity is 115mAh/g; And at 800 ℃ of LiFePO that prepare down
4Particle is bigger, and under same power-discharging density, discharge capacity only is 58mAh/g.
Investigate LiFePO from document and patent
4Method of modifying relatively dull, adopt solid reaction process mostly, need long-time high-temperature calcination.This method not only energy consumption is big, simultaneously for preventing Fe
2+Oxidized, in reaction, need constantly feed protective gas such as high pure nitrogen, cause the preparation process complexity, to the equipment requirements height.In addition, adopt that the polishing batch mixing is difficult to guarantee to mix, the incident complicated side reaction meeting of reactant makes the composition, the structure that synthesize material inhomogeneous in the batch mixing process, causes every performance index poor stability between product batches.Therefore, solid phase reaction preparation technology's repeatability, LiFePO
4Processing characteristics and the difficult control of stability of the chemical property of final products, restricted LiFePO 4 actual industrial process.Though the presoma that sol-gel process and coprecipitation obtain obtains under liquid-phase reaction condition, the predecessor that obtains not is LiFePO
4, LiFePO
4Product all obtains through long-time high-temperature calcination under protective atmosphere, exists and the similar defective of solid reaction process too.Great majority research still rests on and improves its specific capacity under the low current density, and the high-multiplying power discharge specific capacity is not reliablely and stablely improved all the time, causes LiFePO
4Material electrochemical performance is difficult to satisfy the application requirements of electrokinetic cell so far.Exploring suitable process route is the key point that solves industrial problems with the stable parameters that improves LiFePO 4.
Hydro thermal method is the method for a kind of synthesizing superfine powder of development in recent years.This method directly in autoclave, can one step preparation inorganic functional material.Solid product generates from liquid phase, is easy to the performance according to reaction condition regulation and control product.Hydrothermal system is LiFePO simultaneously
4syntheticly provide a closed environment that oxygen content is low, so hydro-thermal is synthetic can not need inert gas shielding, has reduced energy consumption.Some research groups have carried out some research work in this regard.People such as Yang (Hydrothermalsynthesis of lithium iron phosphates cathode[J] .Electrochemistry Communications, 2001 (3): 505-508) with divalent iron salt, LiOH and the H of solubility
3PO
4For raw material under 120 ℃, adopt hydro thermal method to synthesize LiFePO in 5 hours
4Average grain diameter is about 3 μ m, and this material is with 0.14mA/cm
2Current density discharge and recharge, capacity is 100mAh/g.Studies show that the LiFePO 4 that simple hydro thermal method synthesizes does not pass through modification, its poorly conductive, the high-rate discharge ability of material is relatively poor.In order further to improve the LiFePO that hydro thermal method synthesizes
4Chemical property.(application number: 200710058353.7) reported the LiFePO 4 that synthesizes with hydro-thermal as presoma, the follow-up conductive materials carbon that carries out coats and handles patent, to increase its electronic conductivity.The material that synthesizes is tested under the 1C multiplying power, and its specific discharge capacity is 120~140mAh/g.This synthetic method has only been improved the electronic conductivity of material, and to the diffusion coefficient that improves Li ion in the material without any facilitation, thereby can not improve material high magnification chemical property veritably.Patent (application number: 03102665.6) and bibliographical information adopt the similar method synthesizing lithium ferrous phosphate of hydro thermal method, and carry out conductive materials simultaneously and coat and metallic ion-doping modification.They put into reactor in the lump with the base stock of synthesizing lithium ferrous phosphate and conductive materials predecessor and doped metal ion salt, in 5~120 ℃ of synthesis of nano composite precursors, again with this composite precursor 500~800 ℃ of roastings 5~48 hours in nonoxidizing atmosphere, the material that synthesizes is only tested under the 0.5C multiplying power, and material discharge capacity first is 100.0~147.0mAh/g.But in the method for these bibliographical informations, because doped metal ion salt, conductive materials predecessor all add simultaneously at the base stock of hydro-thermal synthesis phase and synthesizing lithium ferrous phosphate, make itself and the base stock of synthesizing lithium ferrous phosphate that mutual interference mutually unavoidably take place, side reaction takes place, make the chemical uniformity of product relatively poor, even can produce the impurity phase, thereby cause the chemical property of product to worsen, be difficult to obtain desirable high magnification chemical property.
Three, summary of the invention
The present invention is directed to the deficiency of in the prior art LiFePO 4 being carried out conductive materials coating modification and metallic ion-doping modification, aim to provide a kind of ferrous lithium anode material of modified phosphate with good high rate capability to be applied to electrokinetic cell, technical problem to be solved is that the auxiliary later stage modification of LiFePO 4 that hydro-thermal synthesizes is handled.The method of modifying that is adopted is: the LiFePO 4 that synthesizes through hydrothermal method is in advance carried out conductive materials simultaneously coat and metallic ion-doping modification.
Technical scheme of the present invention is to be presoma with the synthetic uniform pure phase LiFePO 4 of size, pattern of hydro thermal method, then itself and a certain amount of conductive materials predecessor and metal cation salt is mixed under protective atmosphere and specific temperature to carry out the LiFePO 4 base anode material that roasting just obtains modification.
This method comprises that the hydro thermal method of presoma LiFePO 4 is synthetic, mixing, drying and roasting, it is characterized in that following concrete processing step:
(1) the synthetic at first preparation phosphorus source solution in autoclave that is meant of the hydro thermal method of presoma LiFePO 4, n in molar ratio then
Fe: n
PO4Add source of iron at=1: 1, presses n again
Fe: n
LiSlowly add lithium source solution at=1: 1~3.Add a small amount of reducing agent at last again.Be confined reaction 2~72 hours under the condition of 0.5~2Mpa at 140~250 ℃, self-generated pressure, after the cooling with the product washing, filter and dry, obtain lithium iron phosphate precursor.
(2) lithium iron phosphate precursor that step 1 is prepared mixes the back with conductive materials predecessor and dopant ion salt with certain proportioning and adds small quantity of deionized water, forms uniform slurry after vigorous stirring, with this slurry oven dry, obtains uniform mixture again.Also can with lithium iron phosphate precursor with put into ball mill after conductive materials predecessor and dopant ion salt mix with certain proportioning, add ball-milling medium, oven dry obtains uniform mixture after ball milling 4-8 hour.Wherein the mass ratio of the consumption of conductive materials predecessor and lithium iron phosphate precursor is: 1~20: 100; The consumption of dopant ion salt and the mol ratio of lithium iron phosphate precursor are: 0.5~8: 100.
(3) mixture that step 2 is prepared in inert atmosphere, 300~700 ℃ of roastings 0.5~10 hour, obtain coating dual modified lithium iron phosphate cathode material through metal ion mixing and conductive materials.
Described source of iron is at least a in green vitriol, ferrous oxalate, ferric nitrate, ferrous acetate, frerrous chloride, the iron chloride.
Described phosphorus source is at least a in phosphoric acid, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, sodium phosphate, sodium hydrogen phosphate, the sodium dihydrogen phosphate.
Described lithium source is at least a in lithium carbonate, a hydronium(ion) oxidation lithium, lithium oxalate, lithium acetate, lithium chloride, the lithium sulfate.
Described reducing agent is at least a in hydrochloric acid hydroxylammonium, the ascorbic acid.
Described conductive materials predecessor is selected from glucose, sucrose, starch, acetylene black, charcoal gel, the ascorbic acid etc. at least a.
Described dopant ion salt is selected from Cu
2+, Cr
3+, Ag
+, Zn
2+, Al
3+, Mg
2+, Ti
4+, Nb
5+, Zr
4+Deng at least a acetate or carbonate.
The material that obtains is mixed according to mass ratio with conductive agent acetylene black, binding agent PVDF (Kynoar) respectively at 85: 10: 5, with NMP (1-Methyl-2-Pyrrolidone) this mixture is modulated into slurry, be coated on equably on the collector aluminium foil, at 120 ℃ of vacuumize 24h, make the Experimental cell positive plate.With the lithium sheet is negative pole, and electrolyte is 1mol/L LiPF
6EC (ethyl carbonate ester)+DMC (dimethyl carbonate) (volume ratio 1: 1) solution, barrier film is the celgard2400 film, is assembled into CR2032 type button cell (Experimental cell) in the glove box of argon gas atmosphere.
Compared with the prior art, beneficial effect of the present invention is embodied in:
(1) this method first step adopts Hydrothermal Preparation, is easy to make the LiFePO 4 of size, pattern, even structure by the regulation and control preparation condition.The good processability of product, the having good stability of process repeatability and properties of product.Overcome the repeated relatively poor of solid reaction process preparation technology, shortcomings such as the difficult control of the stability of the processing characteristics of LiFePO 4 and the chemical property of final products.
(2) the batch mixing process in second step of this method is to carry out after the predecessor LiFePO 4 forms, and has improved the chemical uniformity of product effectively, for the high-rate discharge ability that effectively improves product is laid good basis.
(3) the 3rd steps were adopted the roasting in the inert atmosphere, and the coating of realization conductive materials and the doping of metal ion are carried out synchronously.Find that in this process the part metals ion also can be reduced to metal simple-substance by being reduced property conductive materials (as carbon), improve the electronic conductivity of material and the diffusion coefficient of lithium ion so largely, finally realized the raising of ferrousphosphate lithium material high rate performance.
Compare with simple solid reaction process, this method is carried out synthetic and the coating of conductive materials and the doping vario-property of metal ion of LiFePO 4 step by step, has solved the inconsistent problem of LiFePO 4 preparation condition and modified condition well.And the after baking time of this method is short, and energy consumption is little, the size of product, pattern, even structure, and chemical property and processing characteristics have good stable and repeatability.Compare with simple hydro thermal method, the conductive materials in later stage coats and the doping vario-property of metal ion owing to increased, and has greatly improved the electrical conductance of product, and the product that synthesizes has excellent chemical property under high magnification.
Four, description of drawings
Fig. 1 is the XRD figure of pressing the lithium iron phosphate precursor of embodiment one preparation
Fig. 2 is a TEM photo of pressing the lithium iron phosphate precursor of embodiment one preparation
Fig. 3 is the XRD figure of pressing the lithium iron phosphate cathode material of embodiment one preparation
Fig. 4 is the TEM (a that presses the lithium iron phosphate cathode material of embodiment one preparation; B) and FESEM (c; D) photo
Fig. 5 is an XPS collection of illustrative plates of pressing the lithium iron phosphate cathode material of embodiment one preparation
Fig. 6 is a charging and discharging curve of pressing the lithium iron phosphate cathode material of embodiment one preparation
Fig. 7 is the cycle performance figure that presses the lithium iron phosphate cathode material of embodiment one preparation
Fig. 8 for by two kinds of different materials of embodiment one preparation high rate performance figure (■ is the material of preparing under these technical conditions; The material of for only there being conductive materials to coat.)
Fig. 9 is the high rate performance figure that presses the lithium iron phosphate cathode material of embodiment two preparations
Figure 10 is the high rate performance figure that presses the lithium iron phosphate cathode material of embodiment three preparations
Five, embodiment
Embodiment one
1, the preparation of lithium iron phosphate precursor
With 34.506g NH
4H
2PO
4(0.3mol) put into the autoclave of 1L, add the NH that 250ml distilled water forms 1.2mol/L
4H
2PO
4Solution is then with 83.406 gFeSO
47H
2O (0.3mol) adds NH
4H
2PO
4Form uniform milky suspension-turbid liquid in the solution, again with 187.5ml LiOH solution (c
LiOH=4mol/L) joining in the suspension-turbid liquid, the celadon precipitation appears, vigorous stirring, question response back fully adds 62.5ml Vc solution (c
Vc=0.32mol/L).At 210 ℃, self-generated pressure is under the 0.8MPa confined reaction 12-60 hour, after the cooling with the product washing, filter, in 60 ℃ of dryings, obtain lithium iron phosphate precursor.X-ray diffractogram such as Fig. 1 show that product is LiFePO
4, TEM photo such as Fig. 2, crystal grain is a sheet as can be seen, is about to about 500nm.
2, the preparation of the ferrous lithium anode material of modified phosphate
Take by weighing lithium iron phosphate precursor 10g, 1.5g glucose, 0.632g Schweinfurt green, add 10mL distilled water and stirred 10 minutes.Obtain mixture 105 ℃ of following dryings.With this mixture in nitrogen with 600 ℃ of roastings 8 hours, obtain that conductive materials carbon coats, copper ion doped lithium iron phosphate cathode material.
Fig. 3 is the XRD figure of gained material.Since in the later stage modification amount of doped metal ion seldom, and the metal ion that mixes all exists with the form of solid solution, do not change the crystal structure of LiFePO 4.So its XRD figure keeps identical crystal structure with predecessor and LiFePO 4 standard card (JCPDS 40-1499), does not observe other impurity peaks.Fig. 4 is the TEM and the FESEM photo of gained material, shows that this material is the uniform particle of pattern, and particle size is between 300~400nm.(Fig. 5) analyze the valence state of copper in this material by x-ray photoelectron power spectrum (XPS), find that Cu unit have+divalent and two kinds of valence states of 0 valency, this explanation removes the Cu that enters in the lattice
2+Outward, some copper ion is reduced into elemental copper.
The charging and discharging curve of gained ferrousphosphate lithium material such as Fig. 6, under the multiplying power of 0.2C, 0.5C, 1C, 2C, 5C, 10C, the discharge capacity of material is respectively 154,152,146,140,114,107mAh/g.
Fig. 7 is the cycle performance figure of gained ferrousphosphate lithium material.The discharge capacity first of this material is 155mAh/g as can be seen from the figure, and after the charge and discharge cycles 50 times, the discharge capacity of this material still can remain on 154mAh/g, proves that this material has excellent cycle performance.
Be to inquire into the influence that the later stage modification technology produces material electrochemical performance, we only carry out the material that conductive materials coats with the material prepared under these technical conditions and hydro-thermal later stage in early stage and carry out the contrast of high rate performance.Fig. 8 is the high rate performance figure of these two kinds of materials.As can be seen from Figure 8, adopt lithium iron phosphate cathode material that this technology the prepares multiplying power discharging with 0.1C, specific discharge capacity reaches 156mAh/g, when discharge-rate increases to 10C, the specific discharge capacity of material is 107mAh/g, and the conservation rate of capacity is 69%; And the specific discharge capacity of material under the 0.1C multiplying power that only adopts conductive materials to coat is 125mAh/g, and when discharge-rate was increased to 10C, the specific discharge capacity of material only was 58mAh/g, and capability retention is 46%.Contrasted as can be seen by top data, specific discharge capacity and the high rate performance of preparing material under these technical conditions obviously are better than the only material of conductive materials coating.
Embodiment two
With 34.506g NH
4H
2PO
4(0.3mol) put into the autoclave of 1L, add the NH that 250ml distilled water forms 1.2mol/L
4H
2PO
4Solution, then with 83.406g FeSO
47H
2O (0.3mol) adds NH
4H
2PO
4Form uniform milky suspension-turbid liquid in the solution, again with 225ml LiOH solution (c
LiOH=4mol/L) joining in the suspension-turbid liquid, the celadon precipitation appears, vigorous stirring, question response back fully adds 25ml Vc solution (c
Vc=1.2mol/L).At 210 ℃, self-generated pressure is under the 0.8MPa confined reaction 12-60 hour, after the cooling with the product washing, filter, in 60 ℃ of dryings, obtain lithium iron phosphate precursor.
Take by weighing lithium iron phosphate precursor 10g, 0.3g acetylene black, 0.135g Mg (CH
3COO)
2After evenly mixing, as ball-milling medium, obtain mixture 80 ℃ of following dryings behind the ball milling 4-8h with absolute ethyl alcohol.Under 650 ℃ of conditions, calcine 8h at last.Obtain the lithium iron phosphate cathode material that conductive materials coats, magnesium ion mixes.
The high rate performance of this material as shown in Figure 9.With the multiplying power discharging of 0.2C, 0.5C, 1C, 2C, 3C and 4C, the specific discharge capacity of material is respectively 144,135,132,128,120,112mAh/g.
Embodiment three
With 41.407g NH
4H
2PO
4(0.36mol) put into the autoclave of 1L, add the NH that 300ml distilled water forms 1.2mol/L
4H
2PO
4Solution is then with 100.087g FeSO
47H
2O (0.36mol) adds NH
4H
2PO
4Form uniform milky suspension-turbid liquid in the solution, the LiOH solution (LiOH is 0.9mol) with the 4mol/L of 225ml joins in the suspension-turbid liquid again, the celadon precipitation occurs, vigorous stirring, and question response back fully adds 75mlVc solution (c
Vc=0.32mol/L).At 210 ℃, self-generated pressure is under the 0.8MPa confined reaction 12-60 hour, after the cooling with the product washing, filter, in 60 ℃ of dryings, obtain lithium iron phosphate precursor.
Take by weighing hydro-thermal one-step method synthesizing lithium ferrous phosphate 10g, 1.5g glucose, 0.14g Zn (CH
3COO)
2Adding 10mL distilled water stirred 10 minutes.Obtain mixture 105 ℃ of following dryings.With this mixture in nitrogen with 600 ℃ of roastings 8 hours, obtain the lithium iron phosphate cathode material that conductive materials coats, zinc ion mixes.
The high rate performance of this material as shown in figure 10.With the multiplying power discharging of 0.2C, 0.5C, 1C, 2C and 5C, the specific discharge capacity of material is respectively 157,142,129,122 and 97mAh/g.
Claims (3)
1. lithium iron phosphate anode material for lithium ion battery method of modifying, the LiFePO 4 synthetic with hydro thermal method is presoma, comprise mixing, drying and roasting, it is characterized in that: described hydro thermal method is synthetic to be preparation phosphorus source solution in autoclave at first, then n in molar ratio
Fe: n
PO4Add source of iron solution at=1: 1, presses n again
Fe: n
LiSlowly add lithium source solution at=1: 1~3, adds reductant Vc at last, and confined reaction obtained lithium iron phosphate precursor in 12~60 hours under 210 ℃ and self-generated pressure 0.8MPa; Described mixing is a lithium iron phosphate precursor and put into ball mill after conductive materials predecessor and metal cation salt mix in proportion, adds ball-milling medium, and ball milling was dried after 4~8 hours, obtained uniform mixture; Described ratio is that the mass ratio of lithium iron phosphate precursor and conductive materials predecessor is 100: 1~20, and the mol ratio of lithium iron phosphate precursor and metal cation salt is 100: 0.5~8; Described roasting be said mixture in inert atmosphere, 300~700 ℃ of roastings 0.5~10 hour.
2. method of modifying according to claim 1 is characterized in that: described conductive materials predecessor is selected from glucose, sucrose, starch, acetylene black, charcoal gel, the ascorbic acid at least a.
3. method of modifying according to claim 1 and 2 is characterized in that: described metal cation salt is selected from Cu
2+, Cr
3+, Ag
+, Zn
2+, Al
3+, Ti
4+, Nb
5+, Zr
4+In at least a acetate or carbonate.
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CN114551823A (en) * | 2021-12-28 | 2022-05-27 | 江苏容汇通用锂业股份有限公司 | Preparation method and application of metal-doped carbon in-situ coated lithium iron phosphate electrode material |
CN114852986B (en) * | 2022-07-07 | 2022-10-25 | 楚能新能源股份有限公司 | Preparation method of high-compaction lithium iron phosphate and lithium iron phosphate prepared by same |
CN115465849B (en) * | 2022-09-26 | 2024-05-10 | 佛山市德方纳米科技有限公司 | Phosphate positive electrode material and preparation method and application thereof |
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CN1837033A (en) * | 2006-03-24 | 2006-09-27 | 山东科技大学 | Process for synthesizing LiFePO4 as positive electrode materials of lithium ion cell |
CN101121509A (en) * | 2007-07-23 | 2008-02-13 | 河北工业大学 | Hydro-thermal synthetic preparation method for lithium ion battery anode material lithium iron phosphate |
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