The preparation method of ferric phosphate and its ferric phosphate of preparation, the preparation method of LiFePO4
And its LiFePO4 and lithium battery prepared
Technical field
The invention belongs to new energy field, and in particular to before a kind of ferric phosphate for being particularly suitable for LiFePO4 and preparing
Drive ferric phosphate prepared by the preparation method of body and the method, a kind of preparation method of novel phosphoric acid iron lithium and phosphoric acid prepared therefrom
Iron lithium, and the lithium battery including LiFePO4.
Background technology
Lithium iron phosphate electrode material is mainly used in various lithium ion batteries.The NTT Japanese from 1996 is disclosed first
Ay(A is the combination LiFeCoPO of both alkali metal, M Co, Fe to MPO44) olivine structural anode material of lithium battery it
Afterwards, Texas, USA in 1997 stands the research group such as university John.B.Goodenough, has also then reported LiFePO4's
Reversibly move into the characteristic of abjection lithium.Olivine structural (LiMPO is coincidentally delivered with Japan in the U.S.4) so that the material
Material receives great attention, and causes extensive research and rapidly development.With traditional lithium ion secondary battery positive electrode material
Material, the LiMn of spinel structure2O4With the LiCoO of layer structure2Compare, LiMPO4Raw material source more extensively, price it is lower
Honest and clean and non-environmental-pollution.
LiFePO4For firm phosphoric acid tetrahedral framework, because the P-O keys present in crystal structure, even if entering repeatedly
Row discharge and recharge reaction, crystalline texture are also highly stable.For example, even if when material reaches 400 DEG C, oxygen will not be also released, greatly
The security for improving battery, be steady in a long-term and the active material of quick charge;Its source is extensive, toxicity is low simultaneously, safety
Property it is high, thus turn into most important positive electrode active materials used for electric vehicle.
But there is also following deficiency for LiFePO4:Poorly conductive, tap density are low, performance is unstable.
In order to solve these problems, people are explored in terms of three:1) pattern and structure are controlled:Control crystal shape
Looks and granular size;2) coat:In LiFePO4 Surface coating conductive materials, for example, coated with conductive carbon, coats metal powder etc.;
3) adulterate:In LiFePO4 crystal, micro impurity metal ion is introduced, improves electronics and ionic conductivity.
But the performance of existing lithium iron phosphate positive material still needs further to improve, particularly in electric conductivity, shake
Real density and stability etc..And LiFePO4 performance is not only influenceed by the preparation technology of its own, also before by its raw material
Drive the influence of body ferric phosphate.
The content of the invention
It can prepare that electric conductivity is high, tap density is big, stable performance phosphorus it is an object of the invention to provide a kind of
Ferric phosphate presoma of sour iron lithium and preparation method thereof, and the LiFePO4 and the system of the LiFePO4 prepared by the ferric phosphate
Preparation Method and the lithium battery including the LiFePO4.
In order to achieve the above object, scheme of the present invention is:
A kind of preparation method of the ferric phosphate presoma prepared particularly suitable for LiFePO4, methods described include following step
Suddenly:
The step of preparing ferrous sulfate:To containing the aqueous solution that concentration is 30% sulfuric acid and 1-10% organic acids (with quality
Fraction meter) in add and account for aqueous solution quality 15wt% reduced iron powder, the temperature of the aqueous solution is controlled at 60-90 DEG C, so that reduction
Iron powder is reacted with solution, and reaction time control obtains the first reaction solution after the completion of 5-10 hours, reaction, is reacted first
Liquid carries out high Magnetic filter (using the magnetic filter filtering that magnetic is very high) to remove the iron ion of iron simple substance and high price, so as to
Obtain ferrous sulfate aqueous solution;
The organic acid is in lactic acid, malic acid, butanedioic acid, phytic acid or derivatives thereof (referring to foregoing various sour derivatives)
At least one;Organic acid effect is control pH, control ferrous ion stability, meanwhile, some organic acids (such as phytic acid spreads out
Biology) have ratio from carbon in subsequent products of molecular level regulation carbon source, phosphorus source, phosphorus concurrently, so as to optimize subsequent products
The effect of performance.
The step of preparing ferric phosphate process:The ferrous sulfate aqueous solution that previous step is obtained is pumped into reactor, to kettle
It is middle that the mixed liquor being made up of ammonium persulfate, ammonium phosphate and nano-particle controlling agent, and ammonium persulfate, ferrous sulfate and phosphorus is added dropwise
The mol ratio of sour ammonium is 1.05:1:1;
Temperature control adds phosphoric acid control ph to controlling less than 3 to carry out precipitation reaction at 60-80 DEG C, typically adds
The amount of phosphoric acid need 10% or so of ferrous sulfate quality;Precipitation reaction generally requires 5-8 hours, during this period to mixture
It is stirred mixing;In precipitation reaction terminal, mixture is carried out after Magnetic filter using obtaining filter cake after filter press press filtration,
Filter cake is rinsed to remove soluble impurity, then powder processed after spraying drying, obtains phosphoric acid iron product;To obtain high jolt ramming
Density using nanometer controlling agent control ferric phosphate granular size, its act on be control carbon coating organic material and LiFePO4 it
Between interface connecting performance, improve carbon coating compactness, increase carbon LiFePO4 Dispersion on surface uniformity, improve carbon materials
Expect the degree of graphitization in carbonisation, and subtly adjust the ratio of carbon;Described nano-particle controlling agent has following point
Subformula:
Wherein, R is the alkyl that carbon number is 1-18.
This method changes the thing in copperas solution by scene self-control ferrous sulfate and wherein adding organic acid
Matter is formed, also, nano-particle controlling agent is also added into the preparation section of ferric phosphate;Specifically:This nanometer of controlling agent
Nucleocapsid connection material will be used as, while the pattern that control ferric phosphate is formed, while bridging material as core shell structure, connection is next
The glucide of cladding is walked, forms the structure of preliminary sugar-bridging-LiFePO4;That is, it can wrap up some organic substances
On LiFePO4 surface, wherein its residual silicon will be retained in nano-grade lithium iron phosphate, and its residual silicone content is 0.001- after it is sintered
1%.
By the special role of nanometer controlling agent, pattern and microstructure to final product LiFePO4 are carried out this method
Improve;Also, contain in the organic acid and nanometer controlling agent added during prepared by ferrous sulfate and prepared by ferric phosphate
Partial Elements can also enter in final product, so as to produce Beneficial Effect to the performance of final ferric phosphate.
Preferably, the organic acid is that phytic acid is the phytic acid derivative with following molecular structural formula:
Wherein, n 1-100.
The phytic acid derivative is prepared by the following method:By phytic acid and polyethylene glycol in molar ratio 1:1 mole
1wt% hydrochloric acid is added in the reaction unit with water knockout drum than being added to as catalyst, is obtained after being reacted 8 hours in 90 DEG C
To the phytic acid derivative, material is controlled using the derivative prepared as control pH and carbon source.Most preferably, its addition is
5wt%.
The phytic acid derivative except with iron ion ligand complex, control the stability and control solution of iron ion
Outside pH, also have the function that to control to adjust phosphorus source ratio and reduce nucleation energy in ferric phosphate synthesis.The phytic acid of aforementioned proportion exists
With more than 0.1% residual phosphorus rate and more than 0.1% Residual carbon after sintering, this is for adjusting in final LiFePO4 product
Ratio shared by P and C is helpful.
Preferably, the press filtration is completed using vertical type blotter press, and pressure is set as 10-200MPa during press filtration.
A kind of ferric phosphate presoma prepared for LiFePO4, the ferric phosphate is by the side described in any of the above-described
Prepared by method.
A kind of preparation method of LiFePO4, the described method comprises the following steps:
Dispensing:Using ferric phosphate prepared by the above method as source of iron, according to Li/Fe mol ratios 1-1.05 (being preferably 1.03)
Ratio add lithium carbonate, and add 1-20wt% carbon source and 10wt% ball milling liquid, the carbon source is saccharide compound;
Described ball milling liquid refers to that the mixed liquor containing particulate metal ion, described mixed liquor refers to containing at least two
Metal ion species mixed liquor, metal ion include:Na、Mg、Al、Ti、Zr、Mn、Nb、Ti;The metal ion wherein introduced includes
But it is not limited to soluble-salt and complex compound.
Prepare:Said mixture is subjected to ball milling, Ball-milling Time control after 3-5 hours, ball milling size controlling in 0.1-
2.5 micron;Then filtered with the filter press filtration of 800 mesh, the pressure of press filtration is 100-200MPa;It is spray-dried afterwards, will be dry
Powder after dry is kneaded, and mixing time is 2-4 hours, after being kneaded, is granulated to obtain granular precursor into tablet press machine,
Sintering:The particle being granulated is pushed into pre-burning in push pedal vacuum sintering furnace, divides double sintering;First paragraph:Temperature is
150-300 DEG C, the time is 2-4 hours;Second segment:In the vacuum-sintering containing inert gas shielding on the basis of first paragraph sintering
Stove high temperature sinters, and sintering temperature control is at 600-1000 DEG C, sintering time 8-15 hours, so that the abundant graphite of related organic matter
Change, then, be cooled to less than 50 DEG C come out of the stove or be cooled to room temperature after, LiFePO4 product is obtained after crushing.
During heat treatment, produced with water vapour and with precursor Fe3+The generation of the oxidizing gas of reduction, local gas
Concentration distribution has an impact to quality.Therefore, it is necessary to which pre-burning, entirely sintering process will be divided into two sections of progress.
The C that the glucide used decomposites is can be under inactive gas atmosphere of the oxygen concentration below 0.1% by Fe3+
It is reduced to Fe2+Organic matter;It has the effect of adhesive concurrently, can be bonded together ferric phosphate, improves grinding efficiency, especially
It is the high sugar of viscosity.
The saccharide compound, refer to that there is the material of following molecular structure:Cn(H2O)n, wherein n is 2-10;It can be with
As adhesive, reducing agent, sintering pattern controlling agent, react with ferric phosphate, bond LiFePO4, control LiFePO4 burns
Tie pattern;That is, the sugar compounds as carbon source have reduction ferric phosphate, control iron phosphate grains size, nanometer is bonded
The effect of grain forming.Described sugar compounds include:Sucrose, maltose, raffinose, especially stachyose, oligosaccharide.
During LiFePO4 is prepared, to burning out LiFePO4 product, Li, Fe, P and addition since most the step of
The mol ratio of matter-element element keeps constant;Because in different processes, organic matter is all added, so C element mol ratio has
Change, for remaining carbon in control final product, it is necessary to the residual carbon amounts under each firing condition of measured in advance, so as in the first process
It is adjusted in the step of (i.e. the preparation of ferrous sulfate) and the second process the step of (i.e. the preparation of ferric phosphate).
In addition, in above-mentioned 3rd process (i.e. the preparation technology of LiFePO4), preferably with respect to the LiFePO of generation4Addition
1-20wt% polysaccharide, when sugared addition is less than 1wt%, do not show additive effect;During more than 25wt%, it is impossible to effectively subtract
Few out-phase separates out.More preferably 2-15wt%.
Gained LiFePO in the present invention4The grain diameter of/C composite powders, before and after the 3rd process, i.e., before the firing after
It is almost unchanged.Therefore, among the second process or before the 3rd process, by adding aggegation of the organic adhesive by precursor
Grain particle diameter is adjusted to 0.3-30 μm, and the LiFePO of 0.3-30 μm of agglutinating particle particle diameter can be obtained after firing4。
More preferably, inert gas can be N2、Ar、H2O、CO2Or its mixed gas.
Preferably, described in the 3rd process, described mixed liquor includes the carrier of dissolved metal ions, and this carrier removes
Have outside dissolved metal ions function, also there is the function of scattered ferric phosphate, it includes:Ethanol, butanol, propyl alcohol, ethylene glycol,
Polyethylene glycol, polyvinyl alcohol, polyvinyl butyral, butanol, glycol ether, propylene glycol;Most preferably it is butanol.
A kind of LiFePO4, the LiFePO4 is adopted to be prepared with the aforedescribed process.
Preferentially, the particle diameter of the LiFePO4 is 0.3-30 μm;During less than 0.3 μm, positive pole packed density decline and with
The reactivity increase of electrolyte, so not preferably, it is controlled by screening.
A kind of lithium battery, the lithium battery are to be prepared using above-mentioned LiFePO4 as positive electrode.
The LiFePO4 product addition element of the present invention is equably dissolved, and is had defect sturcture by surface modification, is made
The movement of electronics and lithium ion becomes easy;Its tap density is high, and compression forming volume density is 2.0g/cm3More than, therefore fill
Property improve, can improve the energy density of per unit volume.Fe3+Phase content is low, and impurity is few, and residual carbon amounts is 0.5-8wt%,
Impurity crystalline phase Li3PO4It is 0.3-20 μm to measure as below 5wt%, crystallite dimension 25-300nm, agglutinating particle particle diameter, is compressed into
Type volume density is 2.0-2.8g/cm3, charge/discharge cycle characteristics raising.It is controlled by being kneaded, extruding compacting, can be with
Think the LiFePO of the present invention4Powder residual carbon amounts is few, aggegation between primary particle, and compression forming volume density is high.In addition, lithium and
The content of phosphorus is respectively 1-1.02, BET specific surface area 6-35m relative to the mol ratio of iron2/ g, residual carbon amounts are 0.5-
10wt%, crystallite dimension 25-300nm, agglutinating particle particle diameter are 0.3-20 μm, and compression forming volume density is 2.0-2.8g/
cm3, powder resistance rate is 20-200 Ω cm.
The present invention passes through the preparation technology to LiFePO4 preparation technology and raw material, the ferric phosphate for being used as LiFePO4 raw material
And raw material, and the composition of initial raw material ferrous sulfate is improved, and the electric conductivity for the LiFePO4 for making to finally give, shakes
Real density and stability obtain sufficient raising.
Brief description of the drawings
Fig. 1 a are the overall pattern SEM image of the ferric phosphate of embodiment 1;
Fig. 1 b are the nano particle pattern SEM image of the ferric phosphate spherical surface of embodiment 1;
Fig. 2 is the electrochemical performances of lithium iron phosphate figure of embodiment 1;
Fig. 3 is the maltose coated LiFePO 4 for lithium ion batteries TEM image of embodiment 3;
Fig. 4 is LiFePO4 SEM image;
Fig. 5 is LiFePO4 crystal structure figure.
Embodiment
In order that the inventive concept of the present invention may be better understood in those skilled in the art, so as to the protection to the present invention
Scope, which is made, more clearly to be limited, and the present invention is described in detail below in conjunction with the accompanying drawings.
A kind of preparation method of the ferric phosphate presoma prepared for LiFePO4, the described method comprises the following steps:
The step of preparing ferrous sulfate:Add and account in containing the aqueous solution that concentration is 30% sulfuric acid and 1-10% organic acids
Aqueous solution quality 15wt% reduced iron powder, the temperature of the aqueous solution is controlled at 60-90 DEG C, so that reduced iron powder is carried out instead with solution
Should, reaction time control obtains the first reaction solution after the completion of 5-10 hours, reaction, to the first reaction solution high Magnetic filter of progress with
Remove iron simple substance and the iron ion of high price, so as to obtain ferrous sulfate aqueous solution;
The organic acid be lactic acid, malic acid, butanedioic acid, phytic acid or derivatives thereof (refer to lactic acid, malic acid, butanedioic acid or
At least one of the derivative of phytic acid);
The step of preparing ferric phosphate process:The ferrous sulfate aqueous solution that previous step is obtained is pumped into reactor, to kettle
It is middle that the mixed liquor being made up of ammonium persulfate, ammonium phosphate and nano-particle controlling agent, and ammonium persulfate, ferrous sulfate and phosphorus is added dropwise
The mol ratio of sour ammonium is 1.05:1:1;
Temperature control adds phosphoric acid control ph and carries out precipitation reaction to less than 3 at 60-80 DEG C, the phosphorus typically added
The amount of acid needs 10% or so of ferrous sulfate quality;Precipitation reaction generally requires 5-8 hours, and mixture is carried out during this period
It is stirred;In precipitation reaction terminal, mixture is carried out to be pressed into filter cake using filter press after Magnetic filter, rinsed to remove
Soluble impurity, powder processed after spraying drying, obtains phosphoric acid iron product;
Described nano-particle controlling agent has following molecular structural formula:
Wherein, R is the alkyl that carbon number is 1-18.
Above-mentioned nanometer controlling agent will be used as nucleocapsid connection material, while the pattern that control ferric phosphate is formed, while as core
Shell structure bridges material, connects the glucide of cladding in next step, forms the structure of preliminary sugar-bridging-LiFePO4;That is,
Some organic substances can be wrapped in LiFePO4 surface by it, and wherein its residual silicon will be retained in nano-grade lithium iron phosphate, sintering
Its residual silicone content is 0.001-1% afterwards.
More preferably, the organic acid is that phytic acid is the phytic acid derivative with following molecular structural formula:
Wherein, n 1-100.Most preferably, its addition is 5wt%.
The phytic acid derivative is prepared by the following method:By phytic acid and polyethylene glycol in molar ratio 1:1 mole
1wt% hydrochloric acid is added in the reaction unit with water knockout drum than being added to as catalyst, is obtained after being reacted 8 hours in 90 DEG C
To the phytic acid derivative.
Phytic acid derivative is except with the pH with iron ion ligand complex, the stability of control iron ion and control solution
Outside, also have the function that to control to adjust phosphorus source ratio and reduce nucleation energy in ferric phosphate synthesis.The phytic acid of aforementioned proportion is burning
With more than 0.1% residual phosphorus rate and more than 0.1% Residual carbon after knot, this is for adjusting final LiFePO4 product phosphorus
It is helpful with the ratio of carbon.
A kind of ferric phosphate presoma prepared for LiFePO4, the ferric phosphate is by any of the above-described described method
Prepare.
A kind of preparation method of LiFePO4, the described method comprises the following steps:
Dispensing:Using ferric phosphate prepared by the above method as source of iron, carbonic acid is added according to the ratio of Li/Fe mol ratios 1.03
Lithium, and 1-20wt% carbon source and 10wt% ball milling liquid are added, the carbon source is saccharide compound;
Described sugar compounds, refer to that there is the material of following molecular structure:Cn(H2O)n, wherein n is 2-10;It includes:
Sucrose, maltose, raffinose, especially stachyose, oligosaccharide, the C that the glucide used decomposites is can be in oxygen concentration
By Fe under less than 0.1% inactive gas atmosphere3+It is reduced to Fe2+Organic matter;It can be used as adhesive, reducing agent, burning
Pattern controlling agent is tied, reacted with ferric phosphate, bonds LiFePO4, control LiFePO4 sintering pattern;That is, conduct
The sugar compounds of carbon source have reduction ferric phosphate, control iron phosphate grains size, bond the effect of nano particle shaping.
Described ball milling liquid refers to, the mixed liquor containing particulate metal ion, described mixed liquor refer to containing two kinds or
Two or more metal ion mixed liquors, metal ion include:Na、Mg、Al、Ti、Zr、Mn、Nb、Ti;The metal wherein introduced from
Son includes but is not limited to soluble-salt and complex compound.
Prepare:Said mixture is subjected to ball milling, Ball-milling Time control after 3-5 hours, ball milling size controlling in 0.1-
2.5 micron;Then filtered, spray drying, dried powder is kneaded with the filter of 800 mesh, mixing time is that 2-4 is small
When, after being kneaded, it is granulated into tablet press machine,
Sintering:The particle being granulated is pushed into pre-burning in vacuum sintering furnace, divides double sintering;First paragraph:Temperature is 150-
300 DEG C, the time is 2-4 hours;Second segment:On the basis of first paragraph sintering in the vacuum sintering furnace containing inert gas shielding
High temperature sintering, sintering temperature are controlled at 600-1000 DEG C, sintering time 8-15 hours, with abundant graphitization, then, are cooled to 50
Come out of the stove below DEG C, LiFePO4 product is obtained after crushing.More preferably, inert gas can be N2、Ar、H2O、CO2Or its gaseous mixture
Body.
During heat treatment, produced with water vapour and with precursor Fe3+The generation of the oxidizing gas of reduction, local gas
Concentration distribution has an impact to quality.Therefore, it is necessary to which as little as 250-500 DEG C or so of pre-burning, preferably calcined temperature, formal to fire temperature
Degree is carried out with 400-800 DEG C of high temperature.Operation order between pre-burning and formal firing is not particularly limited.
During LiFePO4 is prepared, to burning out LiFePO4 product, Li, Fe, P and addition since most the step of
The molar ratio of matter-element element keeps constant;And because in different processes, organic matter is all added, C element mol ratio has
Change, for remaining carbon in control final product, it is necessary to the residual carbon amounts under each firing condition of measured in advance, so as in the first process
Adjusted in the step of (i.e. the preparation of ferrous sulfate) and the second process the step of (i.e. the preparation of ferric phosphate).
In addition, in above-mentioned 3rd process (i.e. the preparation technology of LiFePO4), preferably with respect to the LiFePO of generation4Addition
1-20wt% polysaccharide, when sugared addition is less than 1wt%, do not show additive effect;During more than 25wt%, it is impossible to effectively subtract
Few out-phase separates out.More preferably 2-15wt%.
Gained LiFePO in the present invention4The grain diameter of/C composite powders, before and after the 3rd process, i.e., before the firing after
It is almost unchanged.Therefore, among the second process or before the 3rd process, by adding aggegation of the organic adhesive by precursor
Grain particle diameter is adjusted to 0.3-30 μm, and the LiFePO of 0.3-30 μm of agglutinating particle particle diameter can be obtained after firing4.Therefore, the side
Before method is additionally included in the 3rd process or will carry out the 3rd process, conductive carbon will be selected from, had Fe3+It is reduced to
Fe2+The electronics conductive auxiliary agent of the sugared lithium iron phosphate particles powder as generation of ability, the control for also serving as sintered particles size
Agent.
Preferably, described in the 3rd process, described mixed liquor includes the carrier of dissolved metal ions, and this carrier removes
Have outside dissolved metal ions functions, also there is the function of scattered ferric phosphate;It includes:Ethanol, butanol, propyl alcohol, ethylene glycol,
Polyethylene glycol;Most preferably it is butanol.
A kind of LiFePO4, the ferric phosphate is adopted to be prepared with the aforedescribed process.
More preferably, the particle diameter of the LiFePO4 is 0.3-30 μm;During less than 0.3 μm, positive pole packed density decline and with
The reactivity increase of electrolyte, so not preferably, it is controlled by screening.
A kind of lithium battery, the lithium battery are to be prepared using above-mentioned ferric phosphate as positive electrode.
Embodiment
The step of preparing ferrous sulfateDevice used includes:High magnetic filter, liner are polytetrafluoroethylene (PTFE), with a high speed
Mixing, the reactor of mixer machine.High magnetic filter adjusts the mixture purity obtained by the step, and high-speed mixer is accelerated anti-
Speed is answered, and inner liner polytetrafluoroethylene reaction is the deep-etching for preventing sulfuric acid and organic acid.
The step of preparing ferric phosphate processDevice used includes:The reaction system of low level reactor, high-order reactor,
Pump, filter press, rinsing device, infrared drying stove, low level reactor.
The process of the preparation of LiFePO4Device used includes in (summation of dispensing, preparation and sintering):Ball mill, essence
Thin ball mill, high magnetic filter, 800 mesh filters, spray-drying installation, kneading device, tabletting extrusion device, vacuum-sintering
Stove, cloth bag pulverizer;LiFePO obtained by it4/ C tap densities can be controlled by mixing, extrusion pressure, bond amount
System.
Embodiment 1
The preparation of nanometer spherical iron phosphate:Iron of high-purity iron content more than 99.8% is put into and fills 30% sulfuric acid and 1%
The liner of the acid solution of phytic acid derivative (being counted using mass fraction) is heated to 95 DEG C as the reactive tank of polytetrafluoroethylene (PTFE), fully reaction
After 20 hours, its pH value is 3;Filtering, degaussing, impurity elimination obtain pure copperas solution, and concentration 170g/L is sub- by sulfuric acid
Ferrous solution 500L squeezes into enamel stills for air blowing, while by the diammonium hydrogen phosphate 72kg dissolved and oxidant ammonium persulfate 50kg 10
Stills for air blowing are added in minute, press filtration, degaussing, cleaning, decontamination fully after reaction, obtain initial pure nano ferric phosphate slurry
Material, its pH value are 5.
Acid ph value with phosphoric acid regulation initial slurry is 2.5, and fully dispersed, squeezes into reactor, adds 0.01% and receives
Rice controlling agent, is heated up to 95 DEG C, reacts 5 hours, initial reactant ferric phosphate crystal grain is formed orderly shaping ball shaped nano crystalline substance,
Filtering, degaussing, rinsing, 150 DEG C of drying obtain nanometer spherical iron phosphate powder.
By nanometer spherical iron phosphate and lithium salts, (iron/phosphorus mol ratio is 1, lithium/phosphorus mol ratio 1.03:1), add and contain metal
Ball milling liquid 2kg, the glucose 46kg containing butanol of ion, addition is fully dispersed in the Scattered Kettle equipped with pure water or solvent, goes
Magnetic 3 hours, 800 turns of rotating speed, ball milling combination machine degaussing is squeezed into, ball milling 6 hours, spray drying, is put into tabletting comminutor tabletting two
Secondary granulation, sintering furnace sinters 750 DEG C in nitrogen protection atmosphere, and the time is 12 hours, obtains lithium iron phosphate positive material.
Initial lithium iron phosphate positive material crushing (such as air-flow crushing or mechanical crushing) is classified, obtaining particle diameter is
The lithium iron phosphate positive material of 0.3-30 μm of suitable lithium ion cell positive coating performance.
Embodiment 2
The preparation of nanometer spherical iron phosphate:Iron of high-purity iron content more than 99.8% is put into and fills 30% sulfuric acid and 5%
The reactive tank of phytic acid derivative, 90 DEG C are heated to, fully reaction 30 hours, its pH value 3;Filtering, degaussing, impurity elimination obtain sulfuric acid Asia
Iron salt solutions, ferrous salt solution 400L is squeezed into enamel stills for air blowing, while the diammonium hydrogen phosphate 58kg and persulfuric acid that will have been dissolved
Ammonium 58kg added stills for air blowing in 15 minutes, press filtration cleaning decontamination fully after reaction, obtained initial pure nano ferric phosphate
Slurry.
Acid ph value using phosphoric acid regulation initial slurry is 2.8, and it is 1% to add nanometer controlling agent, and fully dispersed, is beaten
Enter reactor, be heated up to 95 DEG C, form initial ferric phosphate nanocrystalline, filtering rinsing, 110 DEG C of vacuum dryings obtain nanometer spherical
Ferric phosphate powder.
By nanometer spherical iron phosphate and lithium salts, (iron/phosphorus mol ratio is 1:1.01, lithium/phosphorus mol ratio 1.02:1), addition contains
Ball milling mixing liquid 2kg, the fruit threose 8kg for having metal ion are added in the Scattered Kettle equipped with pure water or solvent fully dispersed 4 hours,
900 turns of rotating speed, ball milling combination machine is squeezed into, ball milling 5 hours, spray drying, tabletting comminutor tabletting secondary granulation is put into, lazy
Property atmosphere sintering furnace sinter 750 DEG C, sintering time be 10 hours, obtain lithium iron phosphate positive material.
Lithium iron phosphate positive material is crushed into (such as air-flow crushing or mechanical crushing) to be classified, it is 0.3-30 to obtain particle diameter
μm suitable lithium-ion battery lithium iron phosphate positive electrode.
Embodiment 3
Iron sheet of high-purity iron content more than 99.8% is put into fill 30% sulfuric acid and 5% phytic acid derivative post poly- four
The reactive tank of PVF, 85 DEG C are heated to, fully reaction 38 hours, its pH value 3;Filtering, degaussing, impurity elimination obtain pure ferrous iron
Salting liquid, ferrous salt solution 420L is squeezed into stills for air blowing, while the diammonium hydrogen phosphate 65kg dissolved and hydrogen peroxide 51kg are existed
Stills for air blowing are added in 25 minutes, press filtration cleaning decontamination fully after reaction, obtain initial pure nano ferric phosphate slurry.
Acid ph value with phosphoric acid regulation initial slurry is 3.0, adds 0.5wt% nanometer controlling agent, and fully dispersed,
Reactor is squeezed into, is heated up to 95 DEG C, forms initial ferric phosphate nanocrystalline, filtering rinsing, 120 DEG C of vacuum dryings obtain nanosphere
Shape ferric phosphate powder.
By nanometer spherical iron phosphate and lithium salts, (iron/phosphorus mol ratio is 0.98:1, lithium/phosphorus mol ratio 1.02:1) ball, is added
Grind mixed solution 3kg, maltose 8kg to add in the Scattered Kettle equipped with pure water or solvent fully dispersed 6 hours, 900 turns of rotating speed, beat
Enter ball milling combination kettle, ball milling 8 hours, spray drying, be put into tabletting comminutor tabletting secondary granulation, burnt in inert atmosphere sintering furnace
750 DEG C of knot, time are 9 hours, obtain initial acid iron lithium anode material.
Initial carbon fusion nanometer spherical high magnification lithium iron phosphate positive material is crushed into (such as air-flow crushing or mechanical crushing)
Classification, obtain particle diameter and merge nanometer spherical high magnification ferric phosphate for the carbon of 0.3-30 μm of suitable lithium ion cell positive coating performance
Lithium anode material.
Embodiment 4
By high-purity iron content more than 99.8% iron be put into fill 30% sulfuric acid and 5% phytic acid derivative liner be poly- four
The reactive tank of PVF, 80 DEG C are heated to, fully reaction 50 hours, pH value 4;Filtering, degaussing, impurity elimination obtain pure ferrous salt
Solution, ferrous salt solution 350L is squeezed into enamel stills for air blowing, while by the diammonium hydrogen phosphate 70kg dissolved and hydrogen peroxide 38kg
Stills for air blowing were added in 30 minutes, press filtration cleaning decontamination fully after reaction, obtain initial pure nano ferric phosphate slurry.With
The acid ph value of phosphoric acid regulation initial slurry is 3.0, and fully dispersed, squeezes into reactor, is heated up to 95 DEG C, makes initial ferric phosphate
Formed nanocrystalline, filtering rinsing, 120 DEG C of vacuum dryings obtain nanometer spherical iron phosphate powder.
By nanometer spherical iron phosphate and lithium salts, (iron/phosphorus mol ratio is 0.98:1, lithium/phosphorus mol ratio 1.03:1) ball, is added
Grind mixed solution 3kg, raffinose 8kg to add in the Scattered Kettle equipped with pure water or solvent fully dispersed 6 hours, 900 turns of rotating speed, beat
Enter ball milling combination kettle, ball milling 8 hours, spray drying, be put into tabletting comminutor tabletting secondary granulation, burnt in inert atmosphere sintering furnace
750 DEG C of knot, time are 9 hours, obtain initial acid iron lithium anode material.
Initial lithium iron phosphate positive material is crushed into (such as air-flow crushing or mechanical crushing) classification, it is 0.3-30 to obtain particle diameter
μm nanometer spherical high magnification lithium iron phosphate positive material.
Comparative example
The preparation of nanometer spherical iron phosphate:Iron of high-purity iron content more than 99.8% is put into the acid solution for filling 30% sulfuric acid
Liner be polytetrafluoroethylene (PTFE) reactive tank, be heated to 95 DEG C, fully reaction 20 hours after, its pH value be 5;Filtering, degaussing, go
It is miscellaneous to obtain pure copperas solution, copperas solution 500L is squeezed into enamel stills for air blowing, while the phosphoric acid that will have been dissolved
The ammonium 72kg of hydrogen two and oxidant ammonium persulfate 50kg added stills for air blowing in 10 minutes, press filtration fully after reaction, degaussing, cleaning,
Decontamination, obtain initial pure nano ferric phosphate slurry.
Acid ph value with phosphoric acid regulation initial slurry is 2.5, and fully dispersed, squeezes into reactor, is heated up to 95 DEG C, instead
Answer 5 hours, initial reactant ferric phosphate crystal grain is formed orderly shaping ball shaped nano brilliant, filtering, degaussing, rinsing, 150 DEG C
Drying obtains nanometer spherical iron phosphate powder.
By nanometer spherical iron phosphate and lithium salts, (iron/phosphorus mol ratio is 1, lithium/phosphorus mol ratio 1.03:1), add and contain metal
Ball milling liquid 2kg, the sugared 46kg containing butanol of ion, addition is fully dispersed in the Scattered Kettle equipped with pure water or solvent, degaussing 3 is small
When, 800 turns of rotating speed squeezes into ball milling combination machine degaussing, ball milling 6 hours, spray drying, is put into that tabletting comminutor tabletting is secondary to make
Grain, sintering furnace sinters 750 DEG C in nitrogen protection atmosphere, and the time is 12 hours, obtains lithium iron phosphate positive material.
Initial lithium iron phosphate positive material crushing (such as air-flow crushing or mechanical crushing) is classified, obtaining particle diameter is
The lithium iron phosphate positive material of 0.3-30 μm of suitable lithium ion cell positive coating performance.
Lithium iron phosphate positive material obtained by above-described embodiment 1-4 and comparative example is fabricated to lithium by identical preparation condition
Battery simultaneously carries out dependence test, and test result is shown in Table 1.
Table 1