CN100595137C - Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate - Google Patents
Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate Download PDFInfo
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- CN100595137C CN100595137C CN200610172612A CN200610172612A CN100595137C CN 100595137 C CN100595137 C CN 100595137C CN 200610172612 A CN200610172612 A CN 200610172612A CN 200610172612 A CN200610172612 A CN 200610172612A CN 100595137 C CN100595137 C CN 100595137C
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Abstract
The invention relates to a preparation method of lithium iron phosphate, an active substance applied in anode of lithium-ion secondary batteries. The method comprises that a mixture that contains lithium compound, iron compound, phosphorus compound and carbon source additive is sintered, cooled to obtain sintering product; wherein, the iron compound comprises ferrous iron compound and ironic phosphate; the sintering method is one-time sintering which is carried out at constant temperature in inert atmosphere or reducing atmosphere. The lithium iron phosphate acquired by the method of the invention has good appearance, small grain size and big tap density, and batteries made of the lithium iron phosphate have high capacity and good cycling performance.
Description
Technical field
The invention relates to a kind of preparation method of battery positive electrode active material, more particularly, is the preparation method about a kind of active material for anode of Li-ion secondary battery LiFePO 4.
Background technology
Lithium ion battery has been widely used in fields such as mobile communication, notebook computer, pick up camera, photographic camera, portable instrument as the high-energy-density chemical power source, also be the electromobile studied energetically of various countries, the first-selected supporting power supply of space power system, become the first-selection of the alternative energy.LiFePO
4It is the research focus of active substance of lithium ion battery anode.LiFePO
4Compare with other battery with positive active material as lithium ion battery and to have good electrochemical, charge and discharge platform is very steady, Stability Analysis of Structures in the charge and discharge process, and having nontoxic, pollution-free, advantage such as safety performance is good, can use under hot environment, starting material wide material sources, is the competitively focus of development research of current battery circle.But LiFePO
4Poor electric conductivity, compare with other active material for anode of Li-ion secondary battery, as cobalt acid lithium (5.1 grams per milliliter), lithium nickelate (4.8 grams per milliliter) and lithium manganate (4.3 grams per milliliter), the density of this material lower (3.6 grams per milliliter), so this has limited the application of LiFePO 4 in practical lithium-ion greatly.
At present, prepare in the method for LiFePO 4, solid phase method technology is simple, and use equipment is realized easily, realizes the earliest in industrialization.Mainly comprising two kinds in the existing solid phase synthesis process, a kind ofly be---the divalence source of iron is as the preparation method of reaction raw materials; Another kind is---ferric iron source is as the preparation method of reaction raw materials.
CN1785799A discloses a kind of preparation method of solid phase synthesis LiFePO 4, the source of iron that this method adopts is a ferrous salt, as Ferrox, Iron diacetate, iron protochloride etc., the phosphorus source is an ammonium phosphate, Secondary ammonium phosphate and primary ammonium phosphate etc., this method comprises lithium salts, above-mentioned ferrous salt and phosphoric acid salt and transition element doped thing are Li: Fe: P: TR=(1-x) by atomic ratio: 1: 1: weighing charging of the mol ratio of x, add the mix grinding medium, 6-12 hour ball milling time, 40-70 ℃ of oven dry down, oven dry back powder heats 400-550 ℃ under inert atmosphere or reducing atmosphere, be incubated 5-10 hour and carry out precalcining; Secondary ball milling 6-12 hour, 40-70 ℃ of oven dry down, under inert atmosphere or reducing atmosphere, 550-850 ℃ of following secondary clacining obtained transition element doped LiFePO 4 powder then.Adopt ferro-compound as source of iron, and the LiFePO 4 tap density of utilizing the method for secondary clacining to obtain is low, the volume of battery specific storage for preparing is low.
CN1775665A discloses the method that a kind of solid phase reduction legal system is equipped with LiFePO 4, this method comprise will contain Li source compound, ferric iron source compound, P source compound and organic additive mix, add organic solvent, in ball mill ball milling 1-8 hour; Then 100-120 ℃ of oven dry; Under 500-800 ℃ of constant temperature sintering 4-24 hour again; Last naturally cooling is worn into powder with the LiFePO 4 solid that makes in ball mill.Adopt the first charge-discharge efficiency of the LiFePO 4 that this method obtains low, preparation material pattern heterogeneity, cycle performance is poor.
Summary of the invention
To the objective of the invention is that the cell container that the LiFePO 4 that adopts prior art for preparing prepares is low, the defective of cycle performance difference in order overcoming, a kind of preparation method who makes battery have the LiFePO 4 of high capacity and good circulation performance to be provided.
The present inventor finds, prepare by existing solid phase method that we recognize in the technology of LiFePO 4, in the existing solid phase synthesis process, only need a general sintering promptly can obtain the relatively large LiFePO 4 of tap density with ferric iron source as the preparation method of the LiFePO 4 of raw material is general, but the capacity of the battery that is prepared by this LiFePO 4 is lower, and cycle performance is poor.
And for adopting the divalence source of iron to be the technology of double sintering as the method for reaction raw materials, purpose is to make the bigger ferrous salt of grain graininess carry out pyrolytic decomposition in the time of the first step incinerating, and then in secondary clacining, can prepare the less LiFePO 4 particle of grain graininess, lithium ion takes off embedding and embedding in solid particulate distance shortens, therefore specific conductivity is also better, and the first charge-discharge effect of the battery that is prepared by this LiFePO 4 is higher.But, in the first step sintering process of pretreatment stage, make oarse-grained ferrous salt, when carrying out pyrolytic decomposition as Ferrox, can emit a large amount of gas,, can cause the material mesoporosity to increase as ammonia, carbonic acid gas etc., short texture, tap density is low, and accumulation property is poor, therefore, the LiFePO 4 granular size irregularity that obtains behind the secondary clacining, though can obtain the ferrous phosphate particle of relative small particle size by twice sintering, because the granular size irregularity, cause tap density low, accumulation property is poor.
The invention provides a kind of preparation method of active material for anode of Li-ion secondary battery LiFePO 4, this method comprises and will contain the mixture sintering of lithium compound, iron cpd, phosphorus compound and carbon source additive, the sintered product that cooling obtains, wherein, described iron cpd comprises ferro-compound and tertiary iron phosphate; Described agglomerating method is constant temperature sintering in inertia or reducing atmosphere.
The present inventor finds unexpectedly, the mixture that adopts ferro-compound and tertiary iron phosphate is as ferrous source material, and with after Li source compound, P source compound and carbon source additive are mixed, it is good not only only to need a step sintering promptly can obtain granule-morphology, the LiFePO 4 that grain graininess is less, tap density is big, and after adopting this LiFePO 4 to be prepared into battery, the capacity of battery is significantly improved, and the cycle performance of battery is good.
Description of drawings
Fig. 1 is the XRD diffractogram of the LiFePO 4 that adopts the inventive method and obtain;
Fig. 2 schemes for the SEM of the LiFePO 4 that employing the inventive method obtains.
Embodiment
According to the present invention, this method comprises and will contain the mixture sintering of lithium compound, iron cpd, phosphorus compound and carbon source additive, the sintered product that cooling obtains, and wherein, described iron cpd comprises ferro-compound and tertiary iron phosphate; Described agglomerating method is constant temperature sintering in inertia or reducing atmosphere.
The present invention adopts is that the mixture of ferro-compound and tertiary iron phosphate is as raw material, because the pattern of iron phosphate grains is better, particle size distribution is even, therefore, the employing tertiary iron phosphate is a skeleton, and mix as ferrous source material with ferro-compound with certain proportion, the particle of the LiFePO 4 that sintering obtains not only pattern is good, even particle size distribution, tap density is big, the more important thing is that the capacity of the battery for preparing is significantly improved, the cycle performance of battery obviously improves.
According to the present invention, the weight mol ratio of described tertiary iron phosphate and ferro-compound is 1-50: 1, be preferably 4-30: 1.
The mol ratio of Li in described lithium compound, ferro-compound, tertiary iron phosphate and the phosphorus compound: Fe: P is (0.9-1.2): 1: 1, it was 1-15 weight % that the consumption of described carbon source additive makes the carbon content in the LiFePO 4 of generation.
Described ferro-compound can be selected from various ferrous iron source compound as the preparation LiFePO 4 well known in the art, as, can be selected from FeC
2O
4, Fe (CH
3COO)
2And Fe
3(PO
4)
2In one or more.
Described lithium compound can be selected from various lithium compound as the preparation LiFePO 4 well known in the art, as, can be selected from Li
2CO
3, LiOH, Li
2C
2O
4, CH
3COOLi, LiH
2PO
4Or Li
3PO
4In one or more.
Described phosphorus compound can be selected from various phosphorus compound as the preparation LiFePO 4 well known in the art, as, can be selected from NH
4H
2PO
4, (NH
4)
2HPO
4, Fe
3(PO
4)
2, LiH
2PO
4, Li
3PO
4(NH
4)
3PO
4In one or more.
Described carbon source additive can be selected from the additive that can play electric action well known in the art, as, can be selected from the luxuriant and rich with fragrance terpolymer of benzene naphthalene, the luxuriant and rich with fragrance copolymer of benzene, benzene anthracene copolymer, poly-in benzene, Zulkovsky starch, polyvinyl alcohol, sucrose, glucose, resol, furfuryl resin, synthetic graphite, natural graphite, superconduction acetylene black, acetylene black, carbon black and the mesocarbon bead one or more.
According to method of the present invention, in order further to improve conductivity of electrolyte materials, also contain compounds of metal M in the described mixture that contains lithium compound, iron cpd, phosphorus compound and carbon source additive.
Described compounds of metal M can be selected from various metal-salt as the preparation LiFePO 4s well known in the art, as, can be selected from oxide compound, oxyhydroxide or the carbonate of Mg, Mn, Ca, Sn, Co, Ni, Mo one or more; As in magnesium oxide, Manganse Dioxide, lime carbonate, tindioxide, tricobalt tetroxide, nickel protoxide, the molybdenum oxide one or more.The mol ratio of Li in described lithium compound, ferro-compound, tertiary iron phosphate and phosphorus compound and the compounds of metal M: M: Fe: P is (0.9-1.2): x: (1-x): 1, and in the formula, M is a metal, 0＜x≤0.3.
The described mixture that contains the compounds of metal M that lithium compound, ferro-compound, tertiary iron phosphate, phosphorus compound and carbon source additive and selectivity add can be by mechanically mixing, grind the mode that is preferably ball milling mixes and obtains.The method of described ball milling comprises mixes ball milling then with the compounds of metal M of lithium compound, ferro-compound, tertiary iron phosphate, phosphorus compound and carbon source additive and selectivity adding with organic solvent, the kind of described organic solvent and consumption are conventionally known to one of skill in the art, as ethanol and/or propyl alcohol, the consumption of organic solvent and the weight ratio of described mixture can be 1-5: 1.The rotating speed of ball milling and time, there is no particular limitation, can granularity as requested need to set.Under the preferable case, adopt the step that also comprises dry this mixture behind this method ball milling, exsiccant method and condition are conventionally known to one of skill in the art.
A described constant temperature agglomerating sintering temperature is 500-900 ℃, is preferably 650-850 ℃, and the constant temperature sintering time is 2-20 hour, is preferably 10-20 hour.
In order further to control the LiFePO 4 granule-morphology, it is more complete that the LiFePO 4 crystal formation is grown, under the preferable case, described agglomerating method is the speed with 1-10 ℃/minute, the speed that is preferably 1-5 ℃/minute is warming up to the constant temperature sintering temperature, and the constant temperature sintering naturally cools to room temperature then.
Described inertia or reducing atmosphere refer to not any one gas or the gaseous mixture with reactant and product generation chemical reaction, as in hydrogen, nitrogen, carbon monoxide, decomposed ammonia and the periodic table of elements zero group gas one or more.This inertia or reducing atmosphere can be static atmosphere, be preferably gas flow rate and be the 2-50 liter/minute mobile atmosphere.
To do further specific descriptions to the present invention by specific embodiment below.
Embodiment 1
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 46.92 gram Li
2CO
3, 45.69 the gram FeC
2O
42H
2O, 152.93 gram FePO
4, 29.22 the gram NH
4H
2PO
4Mix with 350 milliliters of dehydrated alcohols with glucose (Li: Fe: the P mol ratio is 1: 1: 1),, take out 70 ℃ of oven dry with 300 rev/mins rotating speed ball millings 20 hours;
(2) under flow velocity is 10 liters/minute argon shield, the mixture of step (1) was warming up to 700 ℃ of constant temperature sintering 18 hours with 2 ℃/minute heat-up rate, naturally cool to room temperature, carry out comminution by gas stream then, obtain the active material for anode of Li-ion secondary battery LiFePO 4; It is 5 weight % that the consumption of described glucose makes the carbon content in the LiFePO 4 of generation.The tap density of this LiFePO 4 is 1.28 grams per milliliters, median particle diameter D
50It is 4.3 microns.
The XRD diffractogram of this LiFePO 4 that the D/MAX-2200/PC type x-ray powder diffraction instrument of employing Rigaku company records as shown in Figure 1; The SEM that adopts day SSX-550 type scanning electron microscope of island proper Tianjin company (Shimadzu) production to record this LiFePO 4 schemes as shown in Figure 2.
Embodiment 2
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 46.92 gram Li
2CO
3, 18.29 the gram FeC
2O
42H
2O, 172.09 gram FePO
4, 14.61 the gram NH
4H
2PO
4With glucose 3.81 gram SnO
2Mix with 350 milliliters of dehydrated alcohols that (Li: Fe: Sn: the P mol ratio is 1: 0.98: 0.02: 1), with 300 rev/mins rotating speed ball millings 20 hours, take out 70 ℃ of oven dry;
(2) under flow velocity is 10 liters/minute argon shield, the mixture of step (1) was warming up to 750 ℃ of constant temperature sintering 15 hours with 1 ℃/minute heat-up rate, naturally cool to room temperature, carry out comminution by gas stream then, obtain the active material for anode of Li-ion secondary battery LiFePO 4; It is 4 weight % that the consumption of described glucose makes the carbon content in the LiFePO 4 of generation.The tap density of this LiFePO 4 is 1.21 grams per milliliters, median particle diameter D
50It is 3.6 microns.
Embodiment 3
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 46.92 gram Li
2CO
3, 21.24 the gram Fe
3(PO
4)
28H
2O, 172.09 gram FePO
4, 4.87 the gram NH
4H
2PO
4Mix with 250 milliliters of dehydrated alcohols with sucrose (Li: Fe: the P mol ratio is 1: 1: 1),, take out 70 ℃ of oven dry with 300 rev/mins rotating speed ball millings 20 hours;
(2) under flow velocity is 10 liters/minute argon shield, the mixture of step (1) was warming up to 800 ℃ of constant temperature sintering 15 hours with 3 ℃/minute heat-up rate, naturally cool to room temperature, carry out comminution by gas stream then, obtain the active material for anode of Li-ion secondary battery LiFePO 4; It is 3 weight % that the consumption of described sucrose makes the carbon content in the LiFePO 4 of generation.The tap density of this LiFePO 4 is 1.22 grams per milliliters, median particle diameter D
50It is 4.2 microns.
Embodiment 4
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 46.92 gram Li
2CO
3, 29.62 the gram FeC
2O
42H
2O, 162.59 gram FePO
4, 21.74 the gram (NH
4)
2HPO
4Mix with 300 milliliters of dehydrated alcohols with glucose, 1.02 gram MgO (Li: Fe: Mg: the P mol ratio is 1: 0.98: 0.02: 1), with 350 rev/mins rotating speed ball millings 20 hours, taking-up, 70 ℃ of oven dry;
(2) under flow velocity is 10 liters/minute argon shield, the mixture of step (1) was warming up to 650 ℃ of constant temperature sintering 20 hours with 1 ℃/minute heat-up rate, naturally cool to room temperature, carry out comminution by gas stream then, obtain the active material for anode of Li-ion secondary battery LiFePO 4; It is 5 weight % that the consumption of described glucose makes the carbon content in the LiFePO 4 of generation.The tap density of this LiFePO 4 is 1.21 grams per milliliters, median particle diameter D
50It is 3.6 microns.
Embodiment 5
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 46.92 gram Li
2CO
3, 11.52 the gram FeC
2O
42H
2O, 181.59 gram FePO
4, 7.36 the gram NH
4H
2PO
4Mix with 250 milliliters of dehydrated alcohols with acetylene black (Li: Fe: the P mol ratio is 1: 1: 1),, take out 70 ℃ of oven dry with 350 rev/mins rotating speed ball millings 20 hours;
(2) under flow velocity is 10 liters/minute argon shield, the mixture of step (1) was warming up to 700 ℃ of constant temperature sintering 20 hours with 5 ℃/minute heat-up rate, naturally cool to room temperature, carry out comminution by gas stream then, obtain the active material for anode of Li-ion secondary battery LiFePO 4; It is 6 weight % that the consumption of described acetylene black makes the carbon content in the LiFePO 4 of generation.The tap density of this LiFePO 4 is 1.25 grams per milliliters, median particle diameter D
50It is 3.8 microns.
Comparative Examples 1
The preparation method of the positive active material LiFePO 4 of this Comparative Examples explanation prior art
Method according to embodiment 5 prepares LiFePO 4, and different is that the mixture of described lithium-containing compound, iron cpd, phosphorus compound and carbon source additive is 46.99 gram Li
2CO
3, 191.54 the gram FePO
4With the mixture of glucose, it is 6 weight % that the consumption of described glucose makes the carbon content in the LiFePO 4 of generation.This LiFePO 4 particulate tap density that obtains is 1.25 grams per milliliters, median particle diameter D
50It is 4.2 microns.
Comparative Examples 2
The preparation method of the positive active material LiFePO 4 of this Comparative Examples explanation prior art
Method according to embodiment 5 prepares LiFePO 4, and different is do not contain tertiary iron phosphate in the mixture of described lithium-containing compound, iron cpd, phosphorus compound and additive, and described agglomerating method to be a double sintering.Described each substances content is respectively 46.99 gram Li
2CO
3, 228.48 the gram FeC
2O
42H
2O, 146.09 gram NH
4H
2PO
4And glucose, it is 6 weight % that the consumption of described glucose makes the carbon content in the LiFePO 4 of generation.350 ℃ of first sintering temperature, constant temperature sintering 5 hours naturally cools to room temperature then earlier; In second time during sintering, be warming up to 700 ℃ of constant temperature sintering 20 hours with 2 ℃/minute heat-up rates, naturally cool to room temperature, carry out comminution by gas stream then, obtain the active material for anode of Li-ion secondary battery LiFePO 4.The tap density of this LiFePO 4 is 0.85 grams per milliliter, median particle diameter D
50It is 5.2 microns.The LiFePO 4 particle that this method obtains does not have uniform pattern, and the particle size distribution broad.
Embodiment 6-10
The following examples explanation is carried out performance test to battery after adopting positive active material LiFePO 4 provided by the invention to be prepared into battery.
(1) preparation of battery
The anodal preparation
Restrain the positive active material LiFePO that makes by embodiment 1-5 with 90 respectively
4, 5 gram binding agent polyvinylidene difluoride (PVDF) (PVDF) and 5 gram conductive agent acetylene blacks join in the 50 gram N-Methyl pyrrolidone, stir the uniform anode sizing agent of formation then in vacuum mixer.This anode sizing agent is coated on the both sides that thickness is 20 microns aluminium foil equably, 150 ℃ of following oven dry, roll-ins then, cuts to make and be of a size of 540 * 43.5 millimeters positive pole, wherein contain the 5.2 gram activeconstituents LiFePO that have an appointment
4
The preparation of negative pole
90 gram negative electrode active composition natural graphites, 5 gram caking agent polyvinylidene difluoride (PVDF), 5 gram conductive agent carbon blacks are joined in the 100 gram N-Methyl pyrrolidone, in vacuum mixer, stir then and form uniform cathode size.This cathode size is coated on the both sides that thickness is 12 microns Copper Foil equably, then in 90 ℃ of following oven dry, roll-in, cut to make and be of a size of 500 * 44 millimeters negative pole, wherein contain the 3.8 gram activeconstituents natural graphites of having an appointment.
The assembling of battery
Respectively above-mentioned positive and negative electrode and polypropylene screen are wound into the pole piece of a square lithium ion battery, subsequently with LiPF
6Concentration by 1 mol is dissolved in EC/EMC/DEC=1: form nonaqueous electrolytic solution in 1: 1 the mixed solvent, this electrolytic solution is injected the battery aluminum hull with the amount of 3.8g/Ah, lithium-ion secondary cell A1-A5 is made in sealing respectively.
(2) battery performance test
The above-mentioned lithium ion A1-A5 battery that makes is placed on test respectively cashier's office in a shop, carries out constant-current constant-voltage charging with 0.2C earlier, be limited to 4.2 volts in the charging; After shelving 20 minutes, be discharged to 2.5 volts from 4.2 volts with the electric current of 0.2C, the loading capacity first of record battery, and calculate the specific discharge capacity of battery according to the following equation;
Specific discharge capacity=battery is loading capacity (MAH)/positive electrode material weight (gram) first
After repeating above-mentioned steps 30 times and 50 times then, obtain the capacity behind the battery 30 times and 50 times respectively, the loading capacity of record battery.By capacity sustainment rate before and after the following formula computation cycles:
Capacity sustainment rate=(the N time cyclic discharge capacity/cyclic discharge capacity) first * 100%
The result is as shown in table 1 below.
Comparative Examples 3-4
After the positive active material LiFePO 4 that following Comparative Examples explanation adopts prior art to obtain is prepared into battery battery is carried out performance test.
Method according to embodiment 6-10 prepares reference cell AC1-AC2, and the loading capacity first of test battery and the cycle performance of battery, and the specific discharge capacity of calculating battery, different is the reference positive active material LiFePO 4 that the positive active material of preparation used in battery obtains for Comparative Examples 1-2.
The result is as shown in table 1 below.
Table 1
| The embodiment numbering | The battery numbering | Specific discharge capacity (MAH/gram) | The capacity sustainment rate circulates 30 times | The capacity sustainment rate circulates 50 times |
| Embodiment 6 | A1 | 148 | 98.21％ | 97.93％ |
| Embodiment 7 | A2 | 151 | 99.02％ | 98.25％ |
| Embodiment 8 | A3 | 149 | 97.92％ | 97.01％ |
| Embodiment 9 | A4 | 152 | 98.25％ | 97.33％ |
| Embodiment 10 | A5 | 146 | 97.85％ | 97.32％ |
| Comparative Examples 3 | AC1 | 132 | 93.28％ | 90.85％ |
| Comparative Examples 4 | AC2 | 140 | 92.21％ | 88.83％ |
With embodiment 1 is example, and Fig. 1 is the XRD diffractogram of the LiFePO 4 that adopts the inventive method and obtain.As can be seen from the figure, olivine-type structure and the crystal formation of this LiFePO 4 with standard physically well develops.
Fig. 2 amplifies 2000 times stereoscan photograph for the LiFePO 4 that employing the inventive method obtains.As can be seen from the figure, the crystalline particle of LiFePO 4 size homogeneous, particle size distribution is even, and most of particulate diameter is between the 1-3 micron.
Data from last table 1 as can be seen, the initial discharge specific discharge capacity of the battery A1-A5 that the LiFePO 4 that adopts method of the present invention to prepare prepares all is significantly higher than the reference cell AC1-AC2 of Comparative Examples; Capacity sustainment rate after the battery circulation 30 times is more than 97.5%, and the battery A2 of embodiment 2 has reached 99%; Capacity sustainment rate after the battery circulation 50 times also all reaches more than 97%, and reference cell is about the capacity sustainment rate of circulation after 30 times and 50 times only is 93% and 92%, therefore explanation, the battery that the LiFePO 4 that adopts method of the present invention to prepare prepares has heavy body and excellent cycle performance.
Claims (6)
1, a kind of preparation method of active material for anode of Li-ion secondary battery LiFePO 4, this method comprises and will contain the mixture sintering of lithium compound, iron cpd, phosphorus compound and carbon source additive, the sintered product that cooling obtains, it is characterized in that, described iron cpd comprises ferro-compound and tertiary iron phosphate, and the mol ratio of described ferro-compound and tertiary iron phosphate is 1: 1-50; Described agglomerating method is constant temperature sintering in inertia or reducing atmosphere.
2, method according to claim 1, wherein, the mol ratio of Li in described lithium compound, ferro-compound, tertiary iron phosphate and the phosphorus compound: Fe: P is (0.9-1.2): 1: 1, it was 1-15 weight % that the consumption of described carbon source additive makes the carbon content in the LiFePO 4 of generation.
3, method according to claim 1, wherein, the mol ratio of described ferro-compound and tertiary iron phosphate is 1: 4-30.
4, method according to claim 1, wherein, described constant temperature agglomerating temperature is 650-850 ℃, the constant temperature sintering time is 10-20 hour.
5, method according to claim 1, wherein, described ferro-compound is selected from FeC
2O
4, Fe (CH
3COO)
2And Fe
3(PO
4)
2One or more; Described phosphorus compound is selected from NH
4H
2PO
4, (NH
4)
2HPO
4, LiH
2PO
4, Fe
3(PO
4)
2, Li
3PO
4(NH
4)
3PO
4In one or more; Described lithium compound is selected from Li
2CO
3, LiOH, Li
2C
2O
4, CH
3COOLi, LiH
2PO
4Or Li
3PO
4In one or more; Described carbon source additive is selected from the luxuriant and rich with fragrance terpolymer of benzene naphthalene, the luxuriant and rich with fragrance copolymer of benzene, benzene anthracene copolymer, poly-in benzene, Zulkovsky starch, polyvinyl alcohol, sucrose, glucose, resol, furfuryl resin, synthetic graphite, natural graphite, superconduction acetylene black, acetylene black, carbon black and the mesocarbon bead one or more.
6, method according to claim 1 wherein, also contains compounds of metal M in the described mixture that contains lithium compound, iron cpd, phosphorus compound and carbon source additive; Described compounds of metal M is selected from one or more in oxide compound, oxyhydroxide or the carbonate of Mg, Mn, Ca, Sn, Co, Ni, Mo, and the mol ratio of Li: M: Fe: P is (0.9-1.2): x: (1-x): 1, and in the formula, 0＜x≤0.3.
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| CN102637854B (en) * | 2011-02-15 | 2014-06-25 | 北京宏福源科技有限公司 | Preparation method of polyanion cathode material of lithium ion battery |
| CN102340003B (en) * | 2011-09-30 | 2014-09-24 | 淄博惠业铝品电气有限责任公司 | Defect-sensitized lithium ferrous phosphate cathode material and preparation method thereof |
| CN102623699B (en) * | 2012-04-19 | 2014-04-09 | 日照华轩新能源有限公司 | Method for synthesizing high-performance lithium iron phosphate |
| CN109921003A (en) * | 2019-04-18 | 2019-06-21 | 王东升 | A kind of preparation method of high-pressure solid LiFePO4 |
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