The preparation method of quick charging battery material of lithium titanate and lithium titanate/coalescence benzene mixture
Technical field
The invention belongs to the energy and material preparation method, particularly a kind of preparation method who is used for lithium ionic cell cathode material lithium titanate.
Background technology
Along with the stable development of global economy, the output of automobile sharply increases.Fuel-engined vehicle institute exhaust gas discharged causes air environmental pollution.Airborne pollutent 63% comes from vehicle exhaust. and the deterioration day by day of environmental problem, particularly Air quality has caused countries in the world, especially the common concern of developed country.Simultaneously, be becoming tight world petroleum resource day at present, oil price is high all the time.Therefore, the big automobile of national governments and each enterprise is all stepping up to develop no discharging or low emission, is hanging down the cleaning vehicle of oil consumption.Enter the nineties, begin to work out and progressively carry out severe automobile exhaust emission standard based on some western countries of USA and Europe, less energy-consumption, pollution-free green automobile begin to become the focus that people pay close attention to.Electromobile is the green traffic instrument of 21 century. power truck is a zero-emission vehicle, does not have atmosphere polluting problem, and its noise is also low than fuel-engined vehicle.
Following 10 years-20 years will be the stage of power truck high speed development, and high-performance, the research and development of battery and associated materials cheaply will play a decisive role to its development again. and the present power cell that is using and developing mainly contains: lead-acid cell, nickel-cadmium cell, nickel metal hydride battery, lithium ion battery, fuel cell etc. lithium ion battery has operating voltage height (3.6V), energy density height (be respectively Cd/Ni and MH/Ni battery 3 times and 1.5 times), self-discharge little (less than 8%/moon), long and memory-less effect of life-span, advantage such as environmentally friendly most possibly reaches the requirement of power truck.
Since lithium-ions battery is a kind of store battery .1991 that grows up in early 1990s, the following battery of 2Ah capacity obtains widespread use on mobile telephone, notebook computer and pick up camera, it is anodal to adopt lithium cobalt oxide to do, carbon/graphite is made negative pole, and its electrical property and safety performance are accepted by the user.
Concerning power truck, safety is a key issue. existing lithium-ion electric pool technology uses carbon/graphite cathode to lack the inherent security, three major causes are arranged: (1) carbon/graphite inserts lithium near the current potential of metallic lithium, (2) can not carry out high rate charge-discharge. (3) are not charging end indication on voltage curve, be not suitable for being applied in the power truck, must seek a kind of new negative material and replace carbon/graphite.
Li
4Ti
5O
12Be a kind of intercalation compounds, can embed Li+ as negative material the time, volume change is very little, structure does not almost change, be the zero strain material thereby have excellent cycle performance, its spinel structure helps the embedding of lithium ion and deviates from, and voltage platform is positioned at 1.5V (vs.Li/Li
+) near, be difficult for causing that metallic lithium separates out, can carry out high current charge-discharge. lithium titanate has tangible charge and discharge platform in addition, and discharging and recharging has tangible abrupt change of voltage when finishing, and fine grade of little bavin letter found Li
4Ti
5O
12Have good overcharging resisting performance and anti-mistake and put performance.The lithium titanate spinel has the essential characteristic of lithium ion battery of future generation, charging times is more and process of charging is faster, if with the negative material of lithium titanate as lithium ion battery, then under the prerequisite of sacrificing certain energy density, can improve the fast charging and discharging and the cycle performance of system, and it is had significantly discharge and recharge end mark, improve safety performance, being suitable as the electrical source of power of hybrid electric vehicle. lithium titanate is an ideal lithium ion battery negative material of future generation comparatively, and countries such as the U.S., Canada, European Union, Japan, Korea S are all in active research and exploitation.
Rise along with the research of environmental-protecting type electric car, ultracapacitor is as a kind of new secondary power supply, become another research focus behind lithium ion battery, it is found that lithium titanate can be used for substituting a utmost point of gac double layer capacitor, bring into play the advantage of its relative height ratio capacity, become the negative material of the asymmetric ultracapacitor of ideal.
Before and after calendar year 2001, Amatucci group begins Li
4Ti
5O
12: the applied research in the asymmetrical type ultracapacitor, its method is with Li
4Ti
5O
12(Electrochemical Double-layerCapacitors, utmost point EDLC) uses to replace traditional charcoal base double layer capacitor.Because the mechanism difference that capacity produces, in organic electrolyte, the electric double layer capacitance that gac (AC) utmost point forms at " electrode/electrolyte " interface is about 40mAh/g, only is Li
4Ti
5O
12: 1/4 of electrode, so this with intercalation materials of li ions Li
4Ti
5O
12Be negative pole, surface adsorption materials A C is the asymmetric ultracapacitor of anodal " half electrical condenser of half-cell " structure, and the capacity bigger than double layer capacitor can be provided, and keeps the advantage .Li of its long circulation life simultaneously again
4Ti
5O
12This application, having broken through in the past, ultracapacitor uses the metal oxide containing precious metals electrode (as RuO mostly
2, IrO
2) and the restriction of import season pressing the salt electrolytic salt, improved the applicability .Li of asymmetric ultracapacitor greatly
4Ti
5O
12: at electrochemical device, particularly the ultracapacitor aspect is widely used and huge value. because the domestic demand of the continuous development of modern electromobile industry and the exploitation of multiple consumer power supply, and the external requirement that prevents the Sustainable development of lack of energy and environmental degradation, strengthen and accelerate these type of energy-saving and environmental protection, the research and development of electrode materials are efficiently seemed particularly important.
The U.S. developed the very good rechargeable battery of a kind of market outlook in 2005, was anode with the lithium titanate exactly wherein.Report at Britain " New Scientist " weekly first phase in 2005, Nevada, USA Altay technology company develops a kind of rechargeable battery, its duration of charging only needs 6 minutes, and duration of service after the charging and strength of current are 10 times and 3 times of existing general rechargeable battery.It is reported that be positioned at the novel lithium battery that the Altay technology company in Nevada, USA Reno city develops, its anode surface area is very big, can make electronics enter and leave anode rapidly, thereby can finish rapid discharge, and strong current is provided.Altay company research and development responsible official Roy Graham Sodd method of investing is introduced, the smooth surface of carbon anode use because of battery easily and when charging the variation repeatedly of temperature impaired, its work-ing life is generally about 400 charge cycles.And the more rough surface of lithium titanate anode can make cell charging times be up to 20,000 times.The battery longer service life also will help environment.Because this appearance that bigger strength of current battery is provided, the imagination of adding big current consumption function on mobile phone also will become possibility, have the mobile phone of camera function perhaps can have stronger electric power to drive photoflash lamp.
Li
4Ti
5O
12The theoretical embedding lithium capacity of electrode is 175mAh/g, and embedding lithium current potential is 1.55V (vs.Li/Li
+). because the specific conductivity of lithium titanate is lower, in building-up process, its actual specific capacity is generally 120-130mAh/g, and high rate during charging-discharging can not well show, but if its specific storage of nano level lithium titanate can reach 140-150mAh/g and have very good high rate during charging-discharging and quick charge capability.
Summary of the invention
The objective of the invention is to adopt synthetic lithium titanate and the lithium titanate/coalescence benzene composite materials with oxygen vacancy of special technology and method, improve original lithium titanate specific conductivity, high rate during charging-discharging and cycle performance are brought into play well.The present invention uses the high temperature solid-state method that is fit to suitability for industrialized production to carry out a series of chemically modifieds and process modification, and the lithium titanate that synthesizes is suitable for industrialization.
The preparation method of lithium ion battery negative lithium titanate of the present invention/coalescence benzene mixture may further comprise the steps:
(1) coalescence benzene synthetic method: with 1mol phenol and excess formaldehyde at NH
4The OH catalyzer reacted 4-6 hour down, was adjusted to then to neutrality, reacted 2-3 hour again, just obtained resol.Take by weighing a certain amount of resol, adding a certain amount of expanding agent solidified 10-24 hour, place then in the High Temperature Furnaces Heating Apparatus that is connected with automatic temperature control instrument, under nitrogen atmosphere, in 400-1100 ℃ of scope, carry out thermo-cracking, temperature rise rate is 30 ℃/h, the gained material is carried out washing and drying pulverize, and obtains the coalescence benzene electro-conductive material (PAS) that black has metalluster at last.
(2) dip treating: the precursor of lithium salts, titanium is mixed by stoichiometric ratio, add 1%-20%PAS (mass percent) and in organic solvent, flooded 5-30 hour.
(3) mixed precursor: will carry out ball milling 2-10 hour through the mixture that step (2) is handled.
(4) sintering reaction: will calcine 8-24h at 400-1100 ℃ through the dusty material that step (3) is handled, and obtain the matrix material of lithium ionic cell cathode material lithium titanate or lithium titanate/PAS.
Lithium salts is Li
2CO
3, LiOH, LiF, LiBr, LiCl, LiI, Li
3PO
4The precursor of titanium is Detitanium-ore-type TiO
2, rutile TiO
2Protective atmosphere is a non-oxidizing gas, comprises CO
2, N
2, Ar, N
2-H
2, Ar-H
2, H
2The present invention has used coalescence benzene, and this coalescence benzene is different from general conductive polymers, and not only specific conductivity is high but also have bigger specific surface area for it, and this performance for lithium ion battery all is very favorable
The present invention has adopted solid phase method synthesizing lithium ion battery negative material lithium titanate or lithium titanate/PAS matrix material, the starting material wide material sources that adopted, be easy to get, cheap, the preparation method is simple; The matrix material of preparation does not contain Co, Ni etc. has the element of bigger pollution to environment, thereby environmentally friendly; This negative material has the charge and discharge platform about 1.5V stably, and conductivity and high rate during charging-discharging are good; This negative material Stability Analysis of Structures, thermal stability is good, and cycle performance is good.
Lithium ion battery negative lithium titanate or the lithium titanate/PAS matrix material prepared by this method can be widely used in mobile telephone, notebook computer and various handheld device and various electric automobiles.
Description of drawings
Fig. 1 is the crystallogram by the prepared lithium titanate/coalescence benzene matrix material of embodiment 1.(Cu target Ka ray, λ=0.15406nm)
Fig. 2 is a first charge-discharge curve of assembling simulated battery by embodiment 1 prepared lithium titanate/coalescence benzene matrix material.Voltage range 1.2-2.0V, charge-discharge magnification are 0.3C, and probe temperature is 20 ℃.
Fig. 3 is by the cycle performance under the prepared lithium titanate of embodiment 1/coalescence benzene matrix material assembling simulated battery different multiplying.Charge-discharge magnification is 0.3C, 2C, 3C, 4C, 5C, 7C, 9C.Probe temperature is 20 ℃.
Embodiment
Embodiment 1
Coalescence benzene synthetic: with 1mol phenol and excess formaldehyde at NH
4The OH catalyzer reacted 5 hours down, was adjusted to then to neutrality, reacted 2 hours again, just obtained resol.Take by weighing a certain amount of resol, adding a certain amount of expanding agent solidified 15 hours, place then in the High Temperature Furnaces Heating Apparatus that is connected with automatic temperature control instrument, under nitrogen atmosphere, in 600 ℃ of scopes, carry out thermo-cracking, temperature rise rate is 30 ℃/h, the gained material is carried out washing and drying pulverize, and obtains the coalescence benzene electro-conductive material (PAS) that black has metalluster at last
Synthesizing of lithium titanate/coalescence benzene mixture: with Li
2CO
3, Detitanium-ore-type TiO
2(anatase) press stoichiometric, add the PAS (account for synthetic lithium titanate quality 8%) of 8wt% again, adopt the mode of dry grinding, ball milling 3 hours is at N
2Carry out temperature programming in the atmosphere, be raised to 800 ℃ with 3 ℃/min, insulation 12h grinds behind the naturally cooling.
The gained material XRD spectra of surveying is seen Fig. 1, and the reference standard card is a spinel type lithium titanate, makes electrode as follows with the material that embodiment 1 obtains.
Take by weighing the material of embodiment 1 gained respectively with 80: 10: 10 mass ratioes: acetylene black: tetrafluoroethylene, make electrode after grinding evenly, being equipped with pour lithium slice is negative pole, to be dissolved in the 1mol/L LiPF in ethyl-carbonate+methylcarbonate (volume ratio is 1: 1) mixed solvent
6Be electrolytic solution, microporous polypropylene membrane is a barrier film, being assembled into simulated battery. Fig. 2 presses the first charge-discharge curve of 0.3C multiplying power when the 2.0-1.2V stopping potential for respective battery, show that measured battery has the platform of charging/discharging voltage stably about 1.5V, the reversible specific capacity that can calculate embodiment 1 matrix material is still can reach 100mAh/g. Fig. 3 under the 161mAh/g.9C multiplying power to be the cycle performance under the different multiplying, and preceding 50 circulating and reversible capacity descend slightly then that capacity remains unchanged substantially. identical therewith in following examples.
Embodiment 2
Synthesizing of coalescence benzene with embodiment 1, with LiOH, Detitanium-ore-type TiO
2(anatase) press stoichiometric, the PAS (account for synthetic lithium titanate quality 10%) that adds 10wt% again, adopt the mode of wet-milling, dipping is 5 hours in ethanol, carries out ball milling again 8 hours, carries out temperature programming in Ar atmosphere, be raised to 600 ℃ with 3 ℃/min, insulation 8h grinds behind the naturally cooling. and with quadrat method assembling simulated battery, 0.25C multiplying power loading capacity first can reach 160mAh/g.
Embodiment 3
Synthesizing of coalescence benzene with embodiment 1, with LiF, rutile TiO
2(rutile) press stoichiometric, add the PAS (account for synthetic lithium titanate quality 9%) of 9wt% again, dipping is 15 hours in acetone, carried out ball milling again 10 hours, and in Ar atmosphere, carried out temperature programming, be raised to 700 ℃ with 3 ℃/min, insulation 12h grinds behind the naturally cooling.
Embodiment 4
Synthesizing of coalescence benzene with embodiment 1, with LiBr, rutile TiO
2(rutile) press stoichiometric, add the PAS (account for synthetic lithium titanate quality 10%) of 10wt% again, dipping is 30 hours in tetrahydrofuran (THF), carried out ball milling again 5 hours, and in H2 atmosphere, carried out temperature programming, be raised to 800 ℃ with 3 ℃/min, insulation 24h grinds behind the naturally cooling.
Embodiment 5
Synthesizing of coalescence benzene with embodiment 1, with LiCl, Detitanium-ore-type TiO
2(anatase) press stoichiometric, add the PAS (account for synthetic lithium titanate quality 8%) of 8wt% again, dipping is 5 hours in pyridine, carries out ball milling again 3 hours, at N
2-H
2Carry out temperature programming in the atmosphere, be raised to 600 ℃ with 3 ℃/min, insulation 10h grinds behind the naturally cooling.
Embodiment 6
Synthesizing of coalescence benzene with embodiment 1, with LiI, Detitanium-ore-type TiO
2(anatase) press stoichiometric, add the PAS (account for synthetic lithium titanate quality 9%) of 9wt% again, dipping is 5 hours in ethanol, carries out ball milling again 3 hours, at CO
2Carry out temperature programming in the atmosphere, be raised to 700 ℃ with 3 ℃/min, insulation 14h grinds behind the naturally cooling.
Embodiment 7
Synthesizing of coalescence benzene with embodiment 1, with Li
3PO
4, Detitanium-ore-type TiO
2(anatase) press stoichiometric, add the PAS (account for synthetic lithium titanate quality 10%) of 10wt% again, dipping is 5 hours in ethanol, carries out ball milling again 3 hours, at Ar-H
2Carry out temperature programming in the atmosphere, be raised to 800 ℃ with 3 ℃/min, insulation 24h grinds behind the naturally cooling.
Embodiment 8
With Li
2CO
3, Detitanium-ore-type TiO
2(anatase) press stoichiometric, adopt the mode of dry grinding, ball milling 3 hours is at Ar-H
2Carry out temperature programming in the atmosphere, be raised to 600 ℃ with 3 ℃/min, insulation 24h grinds behind the naturally cooling.
Embodiment 9
With LiOH, Detitanium-ore-type TiO
2(anatase) press stoichiometric, dipping is 5 hours in ethanol, and ball milling 8 hours carries out temperature programming in Ar atmosphere, be raised to 700 ℃ with 3 ℃/min, and insulation 8h grinds behind the naturally cooling.
Embodiment 10
With LiF, rutile TiO
2(rutile) press stoichiometric, dipping is 15 hours in acetone, and ball milling 10 hours is at H
2Carry out temperature programming in the atmosphere, be raised to 800 ℃ with 3 ℃/min, insulation 12h grinds behind the naturally cooling.
Embodiment 11
With LiBr, rutile TiO
2(rutile) press stoichiometric, dipping is 30 hours in tetrahydrofuran (THF), and ball milling 5 hours is at CO
2Carry out temperature programming in the atmosphere, be raised to 600 ℃ with 3 ℃/min, insulation 12h grinds behind the naturally cooling.
Embodiment 12
With LiCl, Detitanium-ore-type TiO
2(anatase) press stoichiometric, dipping is 5 hours in pyridine, and ball milling 3 hours is at N
2Carry out temperature programming in the atmosphere, be raised to 800 ℃ with 3 ℃/min, insulation 10h grinds behind the naturally cooling.
Real trip example 13
With LiI, Detitanium-ore-type TiO
2(anatase) press stoichiometric, dipping is 5 hours in ethanol, and ball milling 3 hours is at N
2-H
2Carry out temperature programming in the atmosphere, be raised to 800 ℃ with 3 ℃/min, insulation 10h grinds behind the naturally cooling.
Embodiment 14
With Li
3PO
4, Detitanium-ore-type TiO
2(anatase) press stoichiometric, dipping is 5 hours in ethanol, and ball milling 3 hours is at N
2Carry out temperature programming in the atmosphere, be raised to 800 ℃ with 3 ℃/min, insulation 18h grinds behind the naturally cooling.