Summary of the invention
The purpose of this invention is to provide the asymmetric ferric phosphate lithium cell that a kind of negative pole is main active substances with the lithium titanate.
A kind of negative pole is the asymmetric ferric phosphate lithium cell of main active substances with the lithium titanate, comprise positive pole, negative pole, barrier film and electrolyte, it is characterized in that, the main active substances of described positive pole is an iron phosphate powder, add the iron phosphate powder of active carbon or the iron phosphate powder of interpolation carbon nano-tube, positive electrode also comprises binding agent, conductive agent and dispersant, wherein, each material proportion is closed and is active carbon or carbon nano-tube: iron phosphate powder: binding agent: conductive agent: g:(8~10 dispersant=(0~30) g:(50~80)) g:(10~12) g:(0.6~0.8) L; The main active substances of described negative pole is the lithium titanate powder of lithium titanate powder, lithium titanate powder, complex copper, silver or the carbon nano-tube of adding carbon nano-tube or the lithium titanate powder of partly leading modification, negative material also comprises binding agent, conductive agent and dispersant, wherein, each material proportion is closed and is copper, silver or carbon nano-tube: lithium titanate powder: binding agent: conductive agent: g:(8~10 dispersant=(0~30) g:(50~80)) g:(10~12) g:(0.6~0.8) L.
Described binding agent is a Kynoar.
Described conductive agent is an acetylene black.
Described dispersant is the N-methyl pyrrolidone.
Described complex copper, the potassium titanate powder of silver or carbon nano-tube is at the lithium titanate powder of particle surface clad metal silver or copper or be wound with the lithium titanate nanotube of carbon nano-tube, wherein, the lithium titanate powder of compound silver or copper is by lithium titanate powder and liquor argenti nitratis ophthalmicus or copper-bath, acetaldehyde or hydrazine hydrate, and ammoniacal liquor prepares by chemical deposition, the lithium titanate nanotube of composite carbon nanometer tube is with titanium dioxide, sodium hydroxide solution and salpeter solution are that raw material is when carrying out Hydrothermal Preparation lithium titanate nanotube, carbon nano-tube is added in the reactor with raw material, obtains the lithium titanate nanotube of composite carbon nanometer tube.
Described lithium titanate powder of partly leading modification is for being raw material with metatitanic acid and titanium dioxide, mixture was calcined 3~5 hours at 700~850 ℃ behind ball milling, product after reaction finishes under nitrogen atmosphere through 300~500 ℃ of heat treatments 2~4 hours, with stove cooling, the lithium titanate powder of partly being led modification.
Described iron phosphate powder is the olivine-type iron phosphate powder.
Described lithium titanate powder is the spinel type lithium titanate powder.
Beneficial effect of the present invention is: the battery among the present invention is asymmetric hybrid battery, anodal main active substances is an iron phosphate powder, add the iron phosphate powder of active carbon or the iron phosphate powder of interpolation carbon nano-tube, the main active substances of negative pole is a potassium titanate powder, add the lithium titanate powder of carbon nano-tube, complex copper, the lithium titanate powder of silver or carbon nano-tube or the lithium titanate powder of partly leading modification, mix the hybrid battery of the LiFePO4 of active carbon as positive pole, its charge-discharge performance under the big electric current than existing be that the charge-discharge performance of capacitor under big electric current of electrode is good with active carbon and lithium titanate, can under fast charging and discharging, keep high-specific-power and high-energy-density simultaneously, be fit to be applied in aspects such as electric automobile.
Embodiment
The invention will be further described below in conjunction with accompanying drawing:
Embodiment 1
The preparation of iron phosphate powder is with reference to " a kind of polycrystalline LiFePO of olivine structural
4Powder preparation method " (publication number: CN1410349) with " a kind of LiFePO
4The preparation method of spherical powder " (publication number: CN1648036), iron phosphate powder adopts following method preparation: at first press LiFePO
4In the mole proportioning of each atom, 0.5:1:1 takes by weighing raw material Li in molar ratio
2CO
3, Fe (CO
2)
22H
2O and NH
4H
2PO
4, with raw material ball milling 6 hours and oven dry, about 400 ℃ of The pre-heat treatment are 8 hours under the weakly reducing atmosphere environment, take out after cooling to room temperature with the furnace, and secondary ball milling 6 hours, dry, sieve.For the tap density that increases material to improve the battery volume energy density, powder is carried out mist projection granulating, put it into porcelain boat subsequently, 700 ℃ of roastings 8 hours, take out after cooling to room temperature with the furnace, obtain the LiFePO of olivine structural
4Powder (particle diameter is about 5~20 μ m).
A kind of negative pole is the asymmetric ferric phosphate lithium cell of main active substances with the lithium titanate, comprise positive pole, negative pole, barrier film and electrolyte, the main active substances of described positive pole is for adding the olivine-type iron phosphate powder of active carbon, positive electrode also comprises binding agent, conductive agent and dispersant, wherein, each material proportion is closed, active carbon: iron phosphate powder: binding agent: conductive agent: dispersant=30g:50g:10g:10g:0.7L, described binding agent is a Kynoar, described conductive agent is an acetylene black, and described dispersant is the N-methyl pyrrolidone.Get the LiFePO of the spherical olivine structural of above-mentioned preparation
4Powder (particle diameter is about 5~20 μ m) 2.5g, specific area is about 1500m
2The active carbon 1.5g of/g, binding agent Kynoar (PVDF) 0.5g and conductive agent acetylene black 0.5g, mix the back and add dispersant N-methyl pyrrolidone (NMP) 35ml, stirred 4 hours, on aluminium foil, carry out curtain coating with scraping the skill in using a kitchen knife in cookery then, and place 120 ℃ of following vacuum to obtain anodal diaphragm after dry 1.5 hours.
The main active substances of described negative pole is that the spinel type lithium titanate powder is (commercially available, the lithium titanate powder is a nanoscale, average grain diameter is about 500nm), negative material also comprises binding agent, conductive agent and dispersant, and wherein, each material proportion is closed and is, lithium titanate powder: binding agent: conductive agent: dispersant=80g:10g:10g:0.8L, described binding agent is a Kynoar, and described conductive agent is an acetylene black, and described dispersant is the N-methyl pyrrolidone.Get spinel-type Li
4Ti
5O
12Powder 4.8g, binding agent Kynoar (PVDF) 0.6g and conductive agent acetylene black 0.6g, mix the back and add dispersant N-methyl pyrrolidone (NMP) 48ml, stirred 4 hours, on aluminium foil, carry out curtain coating with scraping the skill in using a kitchen knife in cookery then, and place 120 ℃ of following vacuum to obtain cathode membrane after dry 1.5 hours.
The process of assembling test battery: with positive and negative electrode diaphragm diameter is 12 millimeters drift punching, with assembling CR2032 type button test battery, adopts 1mol/L lithium hexafluoro phosphate (LiPF
6) mixed liquor in ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio of ethylene carbonate and dimethyl carbonate is 1:1) is as electrolyte, it is the barrier film of Sai Er Goethe 2400 (Celgard 2400) that barrier film adopts the U.S. to produce model, packaged battery carries out in the glove box of argon gas atmosphere, makes hybrid battery.
The hybrid battery of present embodiment preparation obtains the charging/discharging voltage curve as shown in Figure 1 through the constant current charge-discharge test, and charge and discharge process comprises A-B, B-C, C-D, E-F, F-G, six processes of G-H.In the A-B stage, along with the carrying out of constant current charge, system voltage constantly raises, and when voltage is elevated to the 1.8V left and right sides, is the B-C stage, and charging is proceeded, and that cell voltage keeps substantially is constant, this moment Li
+Constantly from anodal LiFePO
4In spin off, embed negative pole Li
4Ti
5O
12In.C-D is the last stage of charging, at this moment Li
+Deviate from totally or owing to the reason Li of voltage polarizing
+Can not continue to deviate from from material, in this stage, the voltage of hybrid battery raises along with the rising of specific capacity, is similar to linear relationship, and final charging process finishes.The E-H stage is the discharge overall process, E-F wherein, and F-G, G-H are respectively C-D, the inverse process of B-C and A-B.The constant current charge-discharge cycle performance as shown in Figure 2, along with the raising of charge-discharge magnification, the capacity of battery descends thereupon.Under identical charge-discharge magnification, the circulation repeatedly capacity of back battery also can descend slightly.Discharge capacity in preceding 10 circulations is starkly lower than the charging capacity, and the discharging efficiency of battery in back tens circulations is all more than 95%.Record cyclic voltammetry curve as shown in Figure 3 through cyclic voltammetry, sweep limits is 1.0-3.5V, and sweep speed is 0.01V/s.Hybrid battery is the Faraday pseudo-capacitance characteristic, at 1.5V and 2.2V a pair of redox peak than broad is arranged.
Embodiment 2
A kind of negative pole is the asymmetric ferric phosphate lithium cell of main active substances with the lithium titanate, comprise positive pole, negative pole, barrier film and electrolyte, the main active substances of described positive pole is for adding the olivine-type iron phosphate powder of active carbon, positive electrode also comprises binding agent, conductive agent and dispersant, wherein, each material proportion is closed, active carbon: iron phosphate powder: binding agent: conductive agent: dispersant=10g:70g:10g:10g:0.7L, described binding agent is a Kynoar, described conductive agent is an acetylene black, and described dispersant is the N-methyl pyrrolidone.Get the LiFePO of spherical olivine structural
4Powder (LiFePO
4Powder diameter is about 5~20 μ m, and the preparation method is identical with embodiment 1) 3.5g, specific area is about 1500m
2The active carbon 0.5g of/g, binding agent Kynoar (PVDF) 0.5g and conductive agent acetylene black 0.5g, mix the back and add dispersant N-methyl pyrrolidone (NMP) 35ml, stirred 4 hours, on aluminium foil, carry out curtain coating with scraping the skill in using a kitchen knife in cookery then, and place 120 ℃ of following vacuum to obtain anodal diaphragm after dry 1.5 hours.
The main active substances of described negative pole is the spinel type lithium titanate powder of partly leading modification, (with metatitanic acid and titanium dioxide is raw material, mixture was calcined 4 hours at 800 ℃ behind ball milling, product after reaction finishes under nitrogen atmosphere through 400 ℃ of heat treatments 2 hours, cool off with stove, partly led the lithium titanate powder of modification, the lithium titanate powder of partly leading modification is a nanoscale, average grain diameter is about 500nm), negative material also comprises binding agent, conductive agent and dispersant, wherein, it is that lithium titanate powder: binding agent: conductive agent: dispersant=80g:10g:10g:0.8L, described binding agent are Kynoar that each material proportion is closed, described conductive agent is an acetylene black, and described dispersant is the N-methyl pyrrolidone.Learn from else's experience nitrogen atmosphere second lead the spinel-type Li of modification
4Ti
5O
12Powder 4.8g, binding agent Kynoar (PVDF) 0.6g and conductive agent acetylene black 0.6g, mix the back and add dispersant N-methyl pyrrolidone (NMP) 48ml, stirred 4 hours, on aluminium foil, carry out curtain coating with scraping the skill in using a kitchen knife in cookery then, and place 120 ℃ of following vacuum to obtain cathode membrane after dry 1.5 hours.
The process of assembling test battery: with positive and negative electrode diaphragm diameter is 12 millimeters drift punching, with assembling CR2032 type button test battery, adopts 1mol/L lithium hexafluoro phosphate (LiPF
6) mixed liquor in ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio of ethylene carbonate and dimethyl carbonate is 1:1) is as electrolyte, it is the barrier film of Sai Er Goethe 2400 (Celgard 2400) that barrier film adopts the U.S. to produce model, packaged battery carries out in the glove box of argon gas atmosphere, obtains (the LiFePO that positive pole contains 10% active carbon
4-AC)/Li
4Ti
5O
12Hybrid battery.
The hybrid battery for preparing in the present embodiment obtains the charging/discharging voltage curve as shown in Figure 4 through the constant current charge-discharge test, and similar with Fig. 1, charge and discharge process also comprises A-B, B-C, C-D, E-F, F-G, six processes of G-H, E-F wherein, F-G, G-H are respectively C-D, the inverse process of B-C and A-B.As can be seen, the battery in the embodiment 1, the voltage platform of this battery is longer more flat.The constant current charge-discharge cycle performance as shown in Figure 5, and is similar with Fig. 2, and along with the raising of charge-discharge magnification, the capacity of battery descends thereupon.Under identical charge-discharge magnification, the circulation repeatedly capacity of back battery also can descend slightly.Discharge capacity in preceding 10 circulations is starkly lower than the charging capacity, and the discharging efficiency of battery in back tens circulations is all more than 95%.
Embodiment 3
A kind of negative pole is the asymmetric ferric phosphate lithium cell of main active substances with the lithium titanate, comprise positive pole, negative pole, barrier film and electrolyte, the main active substances of described positive pole is the olivine-type iron phosphate powder, positive electrode also comprises binding agent, conductive agent and dispersant, wherein, each material proportion is closed, iron phosphate powder: binding agent: conductive agent: dispersant=80g:10g:10g:0.67L, described binding agent is a Kynoar, described conductive agent is an acetylene black, and described dispersant is the N-methyl pyrrolidone.Get the LiFePO of spherical olivine structural
4Powder (LiFePO
4Powder diameter is about 5~20 μ m, the preparation method is identical with embodiment 1) 4.8g, binding agent Kynoar (PVDF) 0.6g and conductive agent acetylene black 0.6g, mix the back and add dispersant N-methyl pyrrolidone (NMP) 40ml, stirred 4 hours, on aluminium foil, carry out curtain coating with scraping the skill in using a kitchen knife in cookery then, and place 120 ℃ of following vacuum to obtain anodal diaphragm after dry 1.5 hours.
The main active substances of described negative pole is that (with metatitanic acid and titanium dioxide is raw material for the spinel type lithium titanate powder of compound silver, mixture was calcined 4 hours at 800 ℃ behind ball milling, obtaining the lithium titanate powder, is the spinel-type Li of 0.01mol/L liquor argenti nitratis ophthalmicus, pH value compound 8% (weight) silver that to be 8~9 weak aqua ammonia and acetaldehyde obtain by chemical deposition with lithium titanate powder and concentration
4Ti
5O
12Powder, the spinel type lithium titanate powder of the compound silver that obtains is a nanoscale, average grain diameter is 500nm), negative material also comprises binding agent, conductive agent and dispersant, and wherein, each material proportion is closed and is, silver: lithium titanate powder: binding agent: conductive agent: dispersant=6.4:73.6g:10g:10g:0.8L, described binding agent is a Kynoar, and described conductive agent is an acetylene black, and described dispersant is the N-methyl pyrrolidone.Get the spinel-type Li of compound silver
4Ti
5O
12Powder 4.8g, binding agent Kynoar (PVDF) 0.6g and conductive agent acetylene black 0.6g, mix the back and add dispersant N-methyl pyrrolidone (NMP) 48ml, stirred 4 hours, on aluminium foil, carry out curtain coating with scraping the skill in using a kitchen knife in cookery then, and place 120 ℃ of following vacuum to obtain cathode membrane after dry 1.5 hours.
The process of assembling test battery: with positive and negative electrode diaphragm diameter is 12 millimeters drift punching, with assembling CR2032 type button test battery, adopts 1mol/L lithium hexafluoro phosphate (LiPF
6) mixed liquor in ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio of ethylene carbonate and dimethyl carbonate is 1:1) is as electrolyte, it is the barrier film of Sai Er Goethe 2400 (Celgard 2400) that barrier film adopts the U.S. to produce model, packaged battery carries out in the glove box of argon gas atmosphere, obtains the anodal LiFePO that does not contain active carbon
4/ Li
4Ti
5O
12Hybrid battery.
The hybrid battery for preparing in the present embodiment obtains the charging/discharging voltage curve as shown in Figure 6 through the constant current charge-discharge test, and similar with Fig. 4, charge and discharge process also comprises A-B, B-C, C-D, E-F, F-G, six processes of G-H, E-F wherein, F-G, G-H are respectively C-D, the inverse process of B-C and A-B.Owing to added carbon nano-tube, the voltage platform of battery is not a definite value, but at 1.5V between the 1.9V.The constant current charge-discharge cycle performance as shown in Figure 7, and is similar with Fig. 5, and along with the raising of charge-discharge magnification, the capacity of battery descends thereupon.Under identical charge-discharge magnification, the circulation repeatedly capacity of back battery also can descend slightly.Discharge capacity in preceding 10 circulations is starkly lower than the charging capacity, and the discharging efficiency of battery in back tens circulations is all more than 95%.
Embodiment 4
The preparation method of lithium titanate nanotube is with reference to " the spinel lithium titanate nanotube/line preparation method who is used for lithium battery and capacitor " (publication number: CN1725530): with 5g TiO
2With 70mL concentration is that the NaOH solution of 10m/L mixes, and is 0.2~0.5W/cm at power
2Following sonochemistry reaction 30 minutes, to move into volume then be 100mL, have in the autoclave of teflon lined and carried out hydro-thermal reaction 24 hours, hydrothermal temperature is 150 ℃, after reaction finishes, takes out reactor, naturally cool to room temperature, filtering after opening kettle cover, is that the product to hydro thermal method washed 30 minutes under 2 the condition at pH with the nitric acid of 0.2mol/L concentration, behind the vacuum filtration, product obtains the fluffy powder product of white after 80 ℃ of dryings, be H
2Ti
3O
7Nanotube; With 1.5gH
2Ti
3O
7Nanotube and 40mLLiOH aqueous solution, stir, to move into volume then be 50mL, have in the autoclave of teflon lined and carry out more than the hydro-thermal reaction 24h, preparation nanotube hydrothermal temperature is 100~150 ℃, after reaction finishes, take out reactor, naturally cool to room temperature, filter after opening kettle cover, with deionized water wash for several times, behind the vacuum filtration, filter cake with absolute ethanol washing for several times, product obtains the product of white after 80 ℃ of vacuumize, white product obtains having spinel-type Li through 400 ℃ of heat treatments after 2 hours in air atmosphere
4Ti
5O
12Nanotube, its external diameter is about 10nm, and internal diameter is 4~5nm, is about the hundreds of nanometer to micron order.
A kind of negative pole is the asymmetric ferric phosphate lithium cell of main active substances with the lithium titanate, comprise positive pole, negative pole, barrier film and electrolyte, the main active substances of described positive pole is the olivine-type iron phosphate powder, positive electrode also comprises binding agent, conductive agent and dispersant, wherein, each material proportion is closed, iron phosphate powder: binding agent: conductive agent: dispersant=80g:10g:10g:0.6L, described binding agent is a Kynoar, described conductive agent is an acetylene black, and described dispersant is the N-methyl pyrrolidone.Get the LiFePO of spherical olivine structural
4Powder (LiFePO
4The preparation method of powder is identical with embodiment 1) 4.0g, binding agent Kynoar (PVDF) 0.5g and conductive agent acetylene black 0.5g, mix the back and add dispersant N-methyl pyrrolidone (NMP) 30ml, stirred 4 hours, on aluminium foil, carry out curtain coating with scraping the skill in using a kitchen knife in cookery then, and place 120 ℃ of following vacuum to obtain anodal diaphragm after dry 1.5 hours.
The main active substances of described negative pole is spinel type lithium titanate powder (a lithium titanate nanotube), negative material also comprises binding agent, conductive agent and dispersant, wherein, each material proportion is closed, lithium titanate powder: binding agent: conductive agent: dispersant=80g:10g:10g:0.8L, described binding agent is a Kynoar, and described conductive agent is an acetylene black, and described dispersant is the N-methyl pyrrolidone.Get the spinel-type Li that adopts method for preparing
4Ti
5O
12(its external diameter is about 10nm to lithium titanate nanotube 4.0g, internal diameter is 4~5nm, be about the hundreds of nanometer to micron order), binding agent Kynoar (PVDF) 0.5g and conductive agent acetylene black 0.5g, mix the back and add dispersant N-methyl pyrrolidone (NMP) 40ml, carry out ultrasonicly in supersonic generator, ultrasonic power is 0.2~0.5W/cm
2, 1 hour time, stirred then 4 hours, on aluminium foil, carry out curtain coating with scraping the skill in using a kitchen knife in cookery then, and place 120 ℃ of following vacuum to obtain cathode membrane after dry 1.5 hours.
The process of assembling test battery: with positive and negative electrode diaphragm diameter is 12 millimeters drift punching, with assembling CR2032 type button test battery, adopts 1mol/L lithium hexafluoro phosphate (LiPF
6) mixed liquor in ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio of ethylene carbonate and dimethyl carbonate is 1:1) is as electrolyte, it is the barrier film of Sai Er Goethe 2400 (Celgard 2400) that barrier film adopts the U.S. to produce model, packaged battery carries out in the glove box of argon gas atmosphere, obtains negative pole and uses Li
4Ti
5O
12The LiFePO of nanotube
4/ Li
4Ti
5O
12Hybrid battery.
The hybrid battery for preparing in the present embodiment obtains the charging/discharging voltage curve as shown in Figure 8 through the constant current charge-discharge test, and similar with Fig. 6, charge and discharge process also comprises A-B, B-C, C-D, E-F, F-G, six processes of G-H, E-F wherein, F-G, G-H are respectively C-D, the inverse process of B-C and A-B.Because negative pole adopts the lithium titanate nanotube, the voltage platform of battery is not a definite value, but at 1.5V between the 2.2V.The constant current charge-discharge cycle performance as shown in Figure 9, and is similar with Fig. 7, and along with the raising of charge-discharge magnification, the capacity of battery descends thereupon.Under identical charge-discharge magnification, the circulation repeatedly capacity of back battery also can descend slightly.