CN101209825A - 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
- Publication number
- CN101209825A CN101209825A CNA2006101703300A CN200610170330A CN101209825A CN 101209825 A CN101209825 A CN 101209825A CN A2006101703300 A CNA2006101703300 A CN A2006101703300A CN 200610170330 A CN200610170330 A CN 200610170330A CN 101209825 A CN101209825 A CN 101209825A
- Authority
- CN
- China
- Prior art keywords
- sintering
- compound
- lifepo
- iron
- lithium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention relates to a preparation method of lithium iron phosphate, an active substance applied in the anode of lithium-ion secondary batteries. The method comprises a mixture that contains lithium compound, iron compound, phosphorus compound and carbon source additive is sintered and cooled to get a sintering product; wherein, the iron compound is ferric iron compound; the sintering method is carried out in inert atmosphere or reducing atmosphere; the mixture is sintered at a first constant sintering temperature, and then the sintering product is acquired; the sintering product acquired from sintering at the first sintering temperature is cooled to room temperature and ground; the mixture is sintered at a second constant sintering temperature, and is cooled to room temperature in inert atmosphere or reducing atmosphere; the second sintering temperature is at least 100 DEG C higher than the first sintering temperature. The lithium iron phosphate acquired by the method of the invention has relatively high specific discharge capacity and specific volumetric capacity, and the produced batteries have small size, high capacity and good discharge performance at high current, and the invention can combine the advantages of lithium iron phosphate prepared by taking ferrous iron and ferric iron as iron sources respectively, thus the performance can be remarkably improved.
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 is lower, be 3.6 grams per milliliters, so this has limited the application of LiFePO 4 in practical lithium-ion greatly.
At present, in preparing 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., this method comprises that be Li: Fe: P: TR=(1-x) with lithium salts, ferrous salt and phosphoric acid salt and transition element doped thing 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 that utilizes the method for secondary clacining to obtain to make the specific discharge capacity of the battery that obtains higher relatively, heavy-current discharge performance is better relatively, but tap density is low, and volume and capacity ratio is low, therefore, the battery volume that makes is bigger.
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.The employing ferric iron compound is big as the tap density of the LiFePO 4 that source of iron prepares, the volume and capacity ratio height, and still, specific conductivity is lower, and cell container is not high.
Summary of the invention
The objective of the invention is to adopt the LiFePO 4 of prior art for preparing can not take into account high specific discharge capacity and volume and capacity ratio in order to overcome, make the battery prepare can not take into account the defective of heavy body, good heavy-current discharge performance and smaller size smaller, provide a kind of battery volume that makes less and have the preparation method of the LiFePO 4 of heavy body and good heavy-current discharge performance simultaneously.
The present inventor finds, prepare by existing solid phase method that we recognize in the technology of LiFePO 4, mainly comprise in the existing solid phase synthesis process and adopt the divalence source of iron as the preparation method of reaction raw materials with adopt the preparation method of ferric iron source as reaction raw materials.All adopt agglomerating technology twice for the method that adopts the divalence source of iron as 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 agglomerating, and then in double sintering, can prepare the less LiFePO 4 particle of grain graininess, therefore, specific discharge capacity is higher relatively, in addition, when battery carries out heavy-current discharge, lithium ion takes off embedding and embedding in solid particulate distance shortens, therefore, the heavy-current discharge performance of battery is better relatively.But, in the first step calcining knot process of pretreatment stage, make oarse-grained ferrous salt, when carrying out pyrolytic decomposition, can emit a large amount of gas, as ammonia, carbonic acid gas etc. as Ferrox, can cause the material mesoporosity to increase, short texture, tap density is low, and accumulation property is poor, therefore, the LiFePO 4 granular size irregularity that obtains behind the double sintering, though can obtain the ferrous phosphate particle of relative small particle size by twice sintering,, because granular size irregularity, cause tap density low, accumulation property is poor, so volume and capacity ratio is low.The existing employing in the technology of ferric iron as the feedstock production LiFePO 4, because the difference of source of iron, therefore, only need to adopt and to obtain the relatively large LiFePO 4 particle of tap density once the step sintering, the volume and capacity ratio of the lithium ion battery that the LiFePO 4 that therefore adopts this method to obtain prepares is higher relatively, but the electric conductivity of LiFePO 4 is low, and cell container is not high.
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 is a ferric iron compound; Described agglomerating method is in inertia or reducing atmosphere, and the constant temperature sintering obtains sintered product under first sintering temperature, and the product that the first sintering temperature sintering is obtained is reduced to room temperature then, and grinds; Constant temperature sintering under second sintering temperature, and in inertia or reducing atmosphere, reduce to room temperature, second sintering temperature is higher than at least 100 ℃ of first sintering temperatures.
The present inventor finds unexpectedly, adopt the ferric iron source compound as raw material, and mix with Li source compound, P source compound and carbon source additive, the specific discharge capacity and the volume and capacity ratio that carry out the LiFePO 4 that obtains behind the two-step sintering are all higher, after this LiFePO 4 is prepared into battery, the capacity and the heavy-current discharge performance of battery all are significantly improved, make battery can take into account heavy body and preferable heavy-current discharge performance simultaneously and the battery volume for preparing less.The reason of inferring may be, when adopting ferric iron source to carry out the first step incinerating, under the temperature that is fit to, be preferably 300-less than under 450 ℃, at first be to allow raw material fully react, and there is the part LiFePO 4 to generate, but complete crystallization not, before the second step sintering, again material is carried out ball milling, ball milling reaches and necessarily requires laggard second step of row sintering, can eliminate because the short texture in the first step sintering process, and make material carry out secondary crystal, thus can reform to the LiFePO 4 crystallization, reach the further material pattern that improves, the purpose that size distribution and further crystallization are handled, make the material that obtains adopt ferric one-step calcination technology relatively with existing, the particle diameter that obtains is little, pattern is regular, crystal formation is grown, be evenly distributed and tap density big, therefore, when battery charging and discharging, help shortening lithium ion taking off embedding and embedding diffusion length in LiFePO 4, improved the conductivity of material.Therefore, adopt the specific discharge capacity and the volume and capacity ratio of the LiFePO 4 that such method obtains all higher, therefore can take into account the advantage of the LiFePO 4 that is prepared as source of iron respectively by ferrous iron and ferric iron, improved performance is remarkable.
Description of drawings
Fig. 1 is the XRD diffractogram of the LiFePO 4 that adopts method of the present invention and prepare;
Fig. 2 schemes for the SEM of the mixture that employing method of the present invention obtains behind the first step sintering and ball milling;
Fig. 3 schemes for the SEM of the LiFePO 4 that employing method of the present invention prepares.
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 is a ferric iron compound; Described agglomerating method is in inertia or reducing atmosphere, and the constant temperature sintering obtains sintered product under first sintering temperature, and the product that the first sintering temperature sintering is obtained is reduced to room temperature then, and grinds; Constant temperature sintering under second sintering temperature, and in inertia or reducing atmosphere, reduce to room temperature, second sintering temperature is higher than at least 100 ℃ of first sintering temperatures.
Described ferric iron compound can be selected from various ferric iron source compound as the preparation LiFePO 4 well known in the art, as, can be selected from Fe
2O
3, Fe
3O
4And FePO
4In 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
4And 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, FePO
4, LiH
2PO
4, Li
3PO
4(NH
4)
3PO
4In one or more.
The mol ratio of Li in described lithium compound, ferric iron compound and the phosphorus compound: Fe: P is (0.9-1.2): 1: 1.
Described carbon source additive can be selected from and well known to a person skilled in the art the additive that can play electric action, 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; With described mixture is benchmark, and the consumption of described additive is 1-15 weight %.
According to method of the present invention, in order further to improve the conductivity of material, also preferably 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 compounds of metal M as the preparation LiFePO 4s well known in the art, as, can be selected from oxide compound, oxyhydroxide and 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 and the molybdenum oxide one or more.The mol ratio of Li in described lithium compound, ferric iron compound, phosphorus compound and the metal-salt: 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, ferric iron compound, 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, ferric iron compound, phosphorus compound, 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 1-2: 1.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, can adopt the method for this area routine.
Described first sintering temperature is 300-550 ℃, in order more to help allowing raw material fully react, the part LiFePO 4 is generated, but can not complete crystallization, therefore, under the preferable case, described first sintering temperature is that 300-is less than 450 ℃, the constant temperature agglomerating time is 2-20 hour, is preferably 5-10 hour.
Described second sintering temperature be 600-less than 900 ℃, be preferably 650-800 ℃, the constant temperature agglomerating time is 6-30 hour, is preferably 10-20 hour.
Before constant temperature sintering under second sintering temperature, the product that the first sintering temperature sintering obtains to be reduced to room temperature, and grind, the condition that is preferably ball milling makes the median particle diameter D of the product that the first sintering temperature sintering obtains
50Less than 2 microns, be preferably the 1.35-1.90 micron; D
95Less than 8 microns, be preferably the 5-7 micron.The condition of described ball milling comprises the time of the rotating speed and the ball milling of ball milling, and the rotating speed of described ball milling is 500-1000 rev/min, and the time of ball milling is 5-15 hour.More preferably under the situation, the present invention adopts high energy ball mill, planetary ball mill as Nanjing University, can more help the control of the material particle size that ball milling obtains, make the material of short texture be ground into small-particle, fill up in the macrobead gap, increased the accumulation of material, thereby further improve the tap density of material, the sintering that was second step is laid good basis, the crystal shape of the LiFePO 4 that obtains after making the employing ferric iron compound as source of iron process two-step sintering is regular, even particle size distribution, and tap density is big.In addition, reach the step that need not to sieve again after the above-mentioned particle diameter requirement, can directly carry out the second step sintering step, therefore, simplified technology, saved starting material through this step ball milling.
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 369.5 gram Li
2CO
3, 798.5 the gram Fe
2O
3, 1150.2 the gram NH
4H
2PO
4, 80 gram graphite mix (Li: Fe: the P mol ratio is 1: 1: 1) with 2500 milliliters of dehydrated alcohols, ball milling is 0.5 hour on planetary ball mill, taking-up is dried;
(2) under 350 ℃, flow velocity are 10 liters/minute argon shield,, naturally cool to room temperature with the mixture constant temperature sintering of step (1) 6 hours;
(3) sintered product that step (2) is obtained continued on planetary ball mill high-energy ball milling 6 hours with 900 rev/mins rotating speed, the median particle diameter D of the sintered product that obtains
50It is 1.90 microns; D
95It is 7.74 microns; Then under 650 ℃, flow velocity are 10 liters/minute argon shield,, naturally cool to room temperature and obtain the active material for anode of Li-ion secondary battery LiFePO 4 above-mentioned sintered product constant temperature sintering 10 hours.The tap density of this LiFePO 4 is 1.11 grams per milliliters.
Embodiment 2
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 369.5 gram Li
2CO
3, 758.5 the gram Fe
2O
3, 20 the gram MgO, 1150.2 the gram NH
4H
2PO
4, 228.6 gram glucose and 2500 milliliters of dehydrated alcohols mix that (Li: Fe: Mg: the P mol ratio is 1: 0.95: 0.05: 1), ball milling is 0.5 hour on planetary ball mill, takes out oven dry;
(2) under 350 ℃, flow velocity are 10 liters/minute argon shield,, naturally cool to room temperature with the mixture constant temperature sintering of step (1) 6 hours;
(3) sintered product that step (2) is obtained continued on planetary ball mill high-energy ball milling 8 hours with 900 rev/mins rotating speed, the median particle diameter D of the sintered product that obtains
50It is 1.89 microns; D
95It is 7.56 microns; Then under 650 ℃, flow velocity are 10 liters/minute argon shield,, naturally cool to room temperature and obtain the lithium ion secondary battery anode material LiFePO 4 above-mentioned sintered product constant temperature sintering 10 hours.The tap density of this LiFePO 4 is 1.25 grams per milliliters.
Embodiment 3
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 419.6 gram LiOHH
2O, 798.5 gram Fe
2O
3, 1150.2 the gram NH
4H
2PO
4, 228.6 gram glucose mix (Li: Fe: the P mol ratio is 1: 1: 1) with 3500 milliliters of dehydrated alcohols, ball milling is 0.5 hour on planetary ball mill, taking-up is dried;
(2) under 400 ℃, flow velocity are 8 liters/minute argon shield,, naturally cool to room temperature with the mixture constant temperature sintering of step (1) 10 hours;
(3) sintered product that step (2) is obtained continues the median particle diameter D of the sintered product that obtained in 10 hours at high-energy ball milling on planetary ball mill with 1000 rev/mins rotating speed
50It is 1.63 microns; D
95It is 6.52 microns; Then under 700 ℃, flow velocity are 8 liters/minute argon shield,, naturally cool to room temperature and obtain the lithium ion secondary battery anode material LiFePO 4 above-mentioned sintered product constant temperature sintering 15 hours.The tap density of this LiFePO 4 is 1.25 grams per milliliters.
Embodiment 4
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 369.5 gram Li
2CO
3, 758.5 the gram Fe
2O
3, 50.0 the gram CaCO
3, 1320.2 the gram (NH
4)
2HPO
4, 228.6 gram glucose mix with 3000 milliliters of dehydrated alcohols that (mol ratio of Li: Fe: Ca: P is 1: 0.95: 0.05: 1), ball milling is 0.5 hour on planetary ball mill, and taking-up is dried;
(2) under 350 ℃, flow velocity are 15 liters/minute argon shield,, naturally cool to room temperature with the mixture constant temperature sintering of step (1) 8 hours;
(3) the sintering after product that step (2) is obtained continues the median particle diameter D of the sintered product that high-energy ball milling obtained in 10 hours on planetary ball mill with 700 rev/mins rotating speed
50It is 1.64 microns; D
95It is 7.26 microns; Then under 750 ℃, flow velocity are 15 liters/minute argon shield,, naturally cool to room temperature and obtain the lithium ion secondary battery anode material LiFePO 4 said mixture constant temperature sintering 15 hours.The tap density of this LiFePO 4 is 1.33 grams per milliliters.
Embodiment 5
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 798.5 gram Fe
2O
3, 1039.7 the gram LiH
2PO
4, 393.7 gram polyvinyl alcohol mix (Li: Fe: the P mol ratio is 1: 1: 1) with 2500 milliliters of dehydrated alcohols, ball milling is 0.5 hour on planetary ball mill, taking-up is dried;
(2) under 400 ℃, flow velocity are 15 liters/minute argon shield,, naturally cool to room temperature with the mixture constant temperature sintering of step (1) 10 hours;
(3) sintered product that step (2) is obtained continues the median particle diameter D of the sintered product that high-energy ball milling obtained in 10 hours on planetary ball mill with 600 rev/mins rotating speed
50It is 1.91 microns; D
95It is 7.88 microns; Then under 800 ℃, flow velocity are 15 liters/minute argon shield,, naturally cool to room temperature and obtain the lithium ion secondary battery anode material LiFePO 4 above-mentioned sintered product constant temperature sintering 15 hours.The tap density of this LiFePO 4 is 1.25 grams per milliliters.
Embodiment 6
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 758.5 gram Fe
2O
3, 1039.7 the gram LiH
2PO
4, 20.0 gram MgO, 393.7 gram glucose mix with 2500 milliliters of dehydrated alcohols that (Li: Fe: Mg: the P mol ratio is 1: 0.95: 0.05: 1), ball milling is 0.5 hour on planetary ball mill, and taking-up is dried;
(2) under 400 ℃, flow velocity are 20 liters/minute argon shield,, naturally cool to room temperature with the mixture constant temperature sintering of step (1) 10 hours;
(3) sintered product that step (2) is obtained continues the median particle diameter D of the sintered product that high-energy ball milling obtained in 15 hours on planetary ball mill with 800 rev/mins rotating speed
50It is 1.40 microns; D
95It is 6.23 microns; Then under 700 ℃, flow velocity are 20 liters/minute argon shield,, naturally cool to room temperature and obtain the lithium ion secondary battery anode material LiFePO 4 above-mentioned sintered product constant temperature sintering 15 hours.The tap density of this LiFePO 4 is 1.40 grams per milliliters.
The XRD diffractogram of this LiFePO 4 for preparing that the D/MAX-2200/PC type x-ray powder diffraction instrument of employing Rigaku company records as shown in Figure 1; The SEM with material behind the first sintering product high-energy ball milling that the SSX-550 type scanning electron microscope of employing day island proper Tianjin company (Shimadzu) production records schemes as shown in Figure 2, and the SEM that the SSX-550 type scanning electron microscope that adopts day island proper Tianjin company (Shimadzu) to produce records this LiFePO 4 for preparing schemes as shown in Figure 3.
Embodiment 7
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 758.5 gram Fe
3O
4, 1039.7 the gram LiH
2PO
4, 393.7 the gram glucose, 20.0 the gram Co
3O
4Mix with 2500 milliliters of dehydrated alcohols that (Li: Fe: Co: the P mol ratio is 1: 0.95: 0.05: 1), ball milling is 0.5 hour on planetary ball mill, takes out oven dry;
(2) under 440 ℃, flow velocity are 20 liters/minute argon shield,, naturally cool to room temperature with the mixture constant temperature sintering of step (1) 10 hours;
(3) sintered product that step (2) is obtained continues the median particle diameter D of the sintered product that high-energy ball milling obtained in 15 hours on planetary ball mill with 800 rev/mins rotating speed
50It is 1.7 microns; D
95It is 7.62 microns; Then under 820 ℃, flow velocity are 20 liters/minute argon shield,, naturally cool to room temperature and obtain the lithium ion secondary battery anode material LiFePO 4 above-mentioned sintered product constant temperature sintering 15 hours.The tap density of this LiFePO 4 is 1.18 grams per milliliters.
Embodiment 8
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 1508.2 gram FePO
4, 369.5 the gram Li
2CO
3, 393.7 gram sucrose mix (Li: Fe: the P mol ratio is 1: 1: 1) with 2000 milliliters of dehydrated alcohols, ball milling is 0.5 hour on planetary ball mill, taking-up is dried;
(2) under 430 ℃, flow velocity are 12 liters/minute argon shield,, naturally cool to room temperature with the mixture constant temperature sintering of step (1) 10 hours;
(3) mixture behind the sintering that step (2) is obtained continues the median particle diameter D of the sintered product that high-energy ball milling obtained in 6 hours on planetary ball mill with 600 rev/mins rotating speed
50It is 1.35 microns; D
95It is 6.02 microns; Then under 700 ℃, flow velocity are 12 liters/minute argon shield,, naturally cool to room temperature and obtain the lithium ion secondary battery anode material LiFePO 4 above-mentioned sintered product constant temperature sintering 20 hours.The tap density of this LiFePO 4 is 1.18 grams per milliliters.
Embodiment 9
This embodiment illustrates the preparation of positive active material LiFePO 4 provided by the invention
(1) with 1432.8 gram FePO
4, 369.5 the gram Li
2CO
3, 37.35 gram nickel protoxides and 393.7 gram sucrose mix with 2500 milliliters of dehydrated alcohols that (Li: Fe: Ni: the P mol ratio is 1: 0.95: 0.05: 1), ball milling is 0.5 hour on planetary ball mill, and taking-up is dried;
(2) under 440 ℃, flow velocity are 20 liters/minute argon shield,, naturally cool to room temperature with the mixture constant temperature sintering of step (1) 10 hours;
(3) sintered product that step (2) is obtained continues the median particle diameter D of the sintered product that high-energy ball milling obtained in 10 hours on planetary ball mill with 900 rev/mins rotating speed
50It is 1.63 microns; D
95It is 5.87 microns; Then under 700 ℃, flow velocity are 20 liters/minute argon shield,, naturally cool to room temperature and obtain the lithium ion secondary battery anode material LiFePO 4 above-mentioned sintered product constant temperature sintering 20 hours.The tap density of this LiFePO 4 is 1.33 grams per milliliters.
Comparative Examples 1
The preparation method of the positive active material LiFePO 4 of this Comparative Examples explanation prior art
Method according to embodiment 1 prepares LiFePO 4, and different is to restrain Li with 369.5
2CO
3, 798.5 the gram Fe
2O
3, 1150.2 the gram NH
4H
2PO
4, after 80 gram graphite and 2500 milliliters of dehydrated alcohols are blended on the ball mill ball milling and dry; directly under 650 ℃, flow velocity are 10 liters/minute argon shield; with this mixture constant temperature sintering 10 hours, naturally cool to room temperature and obtain the active material for anode of Li-ion secondary battery LiFePO 4.This LiFePO 4 particulate median particle diameter D that obtains
50It is 5.842 microns; D
95It is 34.56 microns; The tap density of this LiFePO 4 is 0.83 grams per milliliter.
Comparative Examples 2
The preparation method of the positive active material LiFePO 4 of this Comparative Examples explanation prior art
Method according to embodiment 1 prepares LiFePO 4, different is, described iron cpd is a Ferrox, the first step agglomerating temperature is 550 ℃, the rotating speed of the ball milling after the first step sintering is finished is 500 rev/mins, the ball milling time is 5 hours, and other step is identical with embodiment 1 with condition, the LiFePO 4 particulate median particle diameter D that obtains
50It is 2.56 microns; D
95It is 15.62 microns; The tap density of this LiFePO 4 is 0.75 grams per milliliter.
Comparative Examples 3
The preparation method of the positive active material LiFePO 4 of this Comparative Examples explanation prior art
Method according to the disclosed embodiment 1 of CN1775665A prepares the battery positive electrode active material LiFePO 4.The LiFePO 4 particulate average particulate diameter that adopts this method to prepare is the 1-3 micron.
Adopt 0.3 milliampere of electric current to discharge and recharge experiment.Initial discharge capacity is 152.6 MAH/grams.
Embodiment 10-18
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 1-9 with 100 respectively
4, 3 gram binding agent polyvinylidene difluoride (PVDF) (PVDF) and 2 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 2.8 gram activeconstituents LiFePO that have an appointment
4
The preparation of negative pole
100 gram negative electrode active composition natural graphites, 3 gram caking agent polyvinylidene difluoride (PVDF), 3 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 2.6 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-A9 is made in sealing respectively.
(2) battery performance test
The above-mentioned lithium ion A1-A9 battery that makes is placed on test respectively cashier's office in a shop, carries out constant current charge with the 0.2C electric current earlier, the charging upper voltage limit is 3.8 volts, and constant voltage charge is 2.5 hours then; After shelving 20 minutes, be discharged to 3.0 volts with the electric current of 0.2C from 3.8 volts again, the loading capacity first of record battery, and calculate the specific discharge capacity and the volume and capacity ratio of battery according to the following equation;
Specific discharge capacity=battery is loading capacity (MAH)/positive electrode material weight (gram) first
Volume and capacity ratio=battery is loading capacity (MAH)/positive electrode material volume (centimetre 3) first
And then carry out constant current charge with the 0.2C electric current, and being limited to 3.8 volts in the charging, constant voltage charge is 2.5 hours then; After shelving 20 minutes, be discharged to 3.0 volts with the electric current of 1C, 2C and 5C from 3.8 volts respectively, the ratio of the loading capacity when writing down the loading capacity of each battery and calculating respectively with the 0.2C discharge, that is:
C
1C/ C
0.2C: the electric current with 1C is discharged to the loading capacity of 3.0V and the ratio that is discharged to the loading capacity of 3.0V with the electric current of 0.2C from 3.8V from 3.8V;
C
2C/ C
0.2C: the electric current with 2C is discharged to the loading capacity of 3.0V and the ratio that is discharged to the loading capacity of 3.0V with the electric current of 0.2C from 3.8V from 3.8V;
C
5C/ C
0.2C: the electric current with 5C is discharged to the loading capacity of 3.0V and the ratio that is discharged to the loading capacity of 3.0V with the electric current of 0.2C from 3.8V from 3.8V.
The result is as shown in table 1 below.
Comparative Examples 4-6
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 10-18 prepares reference cell AC1-AC3, and the loading capacity first of test battery, and calculates the specific discharge capacity and the volume and capacity ratio of battery; And heavy-current discharge performance, different is the reference positive active material LiFePO 4 that the positive active material of preparation used in battery obtains for Comparative Examples 1-3.
The result is as shown in table 1 below.
Table 1
With embodiment 6 is example, Fig. 3 serves as reasons and adopts method of the present invention to obtain the stereoscan photograph of 2000 times of the amplifications of LiFePO 4, as can be seen from the figure, and the crystalline particle of LiFePO 4 size homogeneous, particle size distribution is even, and most of particulate diameter is between the 1-3 micron.
As can be seen from Figure 1, olivine-type structure and the crystal formation of above-mentioned LiFePO 4 with standard physically well develops.
Data from table 1 as can be seen, and are all undesirable by capacity and the heavy-current discharge performance of the AC1 of the reference cell of the LiFePO 4 preparation of Comparative Examples 1 preparation.Median particle diameter D by the LiFePO 4 of Comparative Examples 2 preparation
50Less, therefore AC2 cell container and the heavy-current discharge performance by the reference cell of this LiFePO 4 preparation makes moderate progress, but because the volume and capacity ratio of this LiFePO 4 is low, if the less battery of preparation volume, the content of active substance ferrous lithium phosphate makes the room for promotion of cell container be restricted in then can the limit battery positive pole.In addition, present electronic product requires quality more and more lighter, and volume is more and more littler, as notebook, so the low using value that has limited this positive electrode material of volume and capacity ratio.Though less by the LiFePO 4 particulate average diameter of particles that Comparative Examples 3 prepares, be the 1-3 micron, the big multiplying power discharging property of the battery that is obtained by this LiFePO 4 granules preparation is poor.
Grain diameter by the positive active material LiFePO 4 of method of the present invention preparation is little, median particle diameter D
50For less than 2 microns, and as can be seen from Figure 3, most of particulate diameter is between the 1-3 micron, and the crystalline particle of LiFePO 4 size homogeneous, and particle size distribution is even, therefore, specific discharge capacity and the volume and capacity ratio of the battery A1-A9 that is prepared by this LiFePO 4 are all higher, and the heavy-current discharge performance of battery is good, and because the volume and capacity ratio height of this LiFePO 4, therefore can prepare the small and exquisite battery of volume, have a good application prospect.
Claims (10)
1. the preparation method of an 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 is a ferric iron compound; Described agglomerating method is in inertia or reducing atmosphere, and the constant temperature sintering obtains sintered product under first sintering temperature, and the product that the first sintering temperature sintering is obtained is reduced to room temperature then, and grinds; Constant temperature sintering under second sintering temperature, and in inertia or reducing atmosphere, reduce to room temperature, second sintering temperature is higher than at least 100 ℃ of first sintering temperatures.
2. method according to claim 1, wherein, described ferric iron compound is selected from Fe
2O
3, Fe
3O
4And FePO
4In one or more.
3. method according to claim 1, wherein, described first sintering temperature be 300-less than 450 ℃, the constant temperature agglomerating time is 2-20 hour.
4. method according to claim 1, wherein, the condition of described grinding makes the median particle diameter D of material
50Less than 2 microns; D
95Less than 8 microns.
5. method according to claim 1, wherein, described second sintering temperature be 600-less than 900 ℃, the constant temperature agglomerating time is 6-30 hour.
6. method according to claim 1, wherein, the mol ratio of Li in described lithium compound, ferric iron compound and the phosphorus compound: Fe: P is (0.9-1.2): 1: 1.
7. method according to claim 1, wherein, described lithium compound is selected from Li
2CO
3, LiOH, Li
2C
2O
4, CH
3COOLi, LiH
2PO
4And Li
3PO
4In one or more.
8. method according to claim 1, wherein, described phosphorus compound is selected from NH
4H
2PO
4, (NH
4)
2HPO
4, FePO
4, LiH
2PO
4, Li
3PO
4(NH
4)
3PO
4In one or more.
9. method according to claim 1, wherein, 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; With described mixture is benchmark, and the content of described carbon source additive is 1-15 weight %.
10. method according to claim 1 wherein, contains in the mixture of lithium compound, iron cpd, phosphorus compound and carbon source additive and also contains compounds of metal M; Described compounds of metal M is selected from one or more in oxide compound, oxyhydroxide and the carbonate of Mg, Mn, Ca, Sn, Co, Ni, Mo, and the mol ratio of described Li: M: Fe: P is (0.9-1.2): x: (1-x): 1, and in the formula, 0＜x≤0.3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2006101703300A CN101209825B (en) | 2006-12-28 | 2006-12-28 | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2006101703300A CN101209825B (en) | 2006-12-28 | 2006-12-28 | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101209825A true CN101209825A (en) | 2008-07-02 |
| CN101209825B CN101209825B (en) | 2010-11-03 |
Family
ID=39610107
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2006101703300A Active CN101209825B (en) | 2006-12-28 | 2006-12-28 | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101209825B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102315448A (en) * | 2010-06-30 | 2012-01-11 | 株式会社半导体能源研究所 | Be used to make the method for energy accumulating device |
| CN102751493A (en) * | 2012-06-27 | 2012-10-24 | 武陟县鑫凯科技材料有限公司 | Preparation method of lithium iron phosphate |
| CN102916191A (en) * | 2012-09-21 | 2013-02-06 | 深圳市贝特瑞新能源材料股份有限公司 | Uniformly dispersed electrode material and preparation method thereof |
| CN112054183A (en) * | 2020-09-03 | 2020-12-08 | 深圳澳睿新能源科技有限公司 | Method for preparing material with component gradient characteristic and application of material in battery |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1794497A (en) * | 2005-11-01 | 2006-06-28 | 中国科学院成都有机化学有限公司 | Bulk phase-doped modified lithium ion battery positive electrode material and its preparation method |
-
2006
- 2006-12-28 CN CN2006101703300A patent/CN101209825B/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102315448A (en) * | 2010-06-30 | 2012-01-11 | 株式会社半导体能源研究所 | Be used to make the method for energy accumulating device |
| CN102751493A (en) * | 2012-06-27 | 2012-10-24 | 武陟县鑫凯科技材料有限公司 | Preparation method of lithium iron phosphate |
| CN102916191A (en) * | 2012-09-21 | 2013-02-06 | 深圳市贝特瑞新能源材料股份有限公司 | Uniformly dispersed electrode material and preparation method thereof |
| CN112054183A (en) * | 2020-09-03 | 2020-12-08 | 深圳澳睿新能源科技有限公司 | Method for preparing material with component gradient characteristic and application of material in battery |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101209825B (en) | 2010-11-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101399343B (en) | Preparing method of anode active material lithium iron phosphate for lithium ionic secondary cell | |
| CN101636351B (en) | Compound having olivine-type structure, positive electrode for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery | |
| CN100340018C (en) | Lithium transition-metal phosphate powder for rechargeable batteries | |
| CN101209827B (en) | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate | |
| JP4082214B2 (en) | Nonaqueous electrolyte secondary battery and its positive electrode active material | |
| CN101209824B (en) | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate | |
| KR100898871B1 (en) | Method for preparing lithium metal phosphate | |
| CN101494288B (en) | Preparation method for lithium ion secondary battery anode material ferric lithium phosphate | |
| US20230322557A1 (en) | Method for preparing lithium manganese iron phosphate, cathode material, and lithium-ion battery | |
| CN101568489B (en) | Method for preparing lithium iron phosphate as a positive electrode active material for a lithium ion secondary battery | |
| CA2334003A1 (en) | Active material of positive plate, nonaqueous electrolyte secondary cell, method for producing active material of positive material | |
| CN101339991B (en) | Composite coated modified high vibrancy solid lithium ionic battery positive electrode, preparation and application thereof | |
| JP2013541142A (en) | Anode active material for lithium secondary battery, method for producing the same, and lithium secondary battery including the same | |
| CN101209822B (en) | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate | |
| CN101209823B (en) | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate | |
| CN101209825B (en) | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate | |
| EP3890068B1 (en) | Positive electrode material for lithium ion secondary battery, positive electrode for lithium ion secondary battery, and lithium ion secondary battery | |
| CN100595137C (en) | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate | |
| CN101209826B (en) | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate | |
| EP2892092B1 (en) | Electrode material, electrode and lithium ion battery | |
| CN101209829B (en) | Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate | |
| CN101407318A (en) | Method for preparing active substance lithium iron phosphate for lithium ion secondary battery anode |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |