Embodiment
as shown in Figure 1,the present invention is the preparation method of the coated porous LiFePO 4 powder of a kind of carbon, the steps include:
(1) Fe
2o
3colloid preparation: take source of iron, be dissolved in deionized water and be mixed with Fe
3+in the solution of concentration 0.1~1mol/L, adopt the ammoniacal liquor of mass concentration 10% or urea liquid as precipitation reagent, the organic molecule dispersant is dissolved in deionized water as end liquid, mol ratio is: dispersant: Fe
3+=1:10, pH=6.8-7.0;
(2) by Fe
3+solution and precipitation reagent add end liquid simultaneously, control pH=7.0-13.0 to Fe
2o
3.nH
2o precipitates fully; By after precipitate and separate, washing, under stirring, with mol ratio HCl:Fe
2o
3=1:100-1:500 adds the watery hydrochloric acid of 0.01mol/L to carry out acidifying, obtains electropositive Fe
2o
3.nH
2the O colloidal particle; Colloidal particle by centrifugation after, add deionized water, add surfactant simultaneously, mass ratio is: surfactant: Fe
2o
3=1:10-1:100 stirs under 30-100 ℃, and mixing time continues 1-10h, obtains Fe
2o
3the Fe that mass ratio is 5-30%
2o
3.nH
2the O colloid;
(3) slurry preparation: according to stoichiometric proportion Li
xfe
ypO
4: M
z, wherein M is the doping ion, x=0.8-1.2, and y=0.8-1.2, z=0.01-0.1, take ,Lin source, lithium source and doping metals compound, and the addition of carbon source is Li
xfe
ypO
4: M
zmass ratio 5-20%; ,Lin source, lithium source, carbon source and doping metals compound are joined to Fe
2o
3.nH
2in the O colloid, continue to be stirred, form homodisperse gluey mixed slurry;
(4) presoma preparation: adopt the spray drying mode to carry out drying to slurry, inlet temperature is 110-130 ℃, obtain composition evenly, the spherical LiFePO 4 presoma of even particle size distribution;
(5) calcining: spray drying gained presoma is put into to crucible, be warming up to 500~800 ℃ under inert atmosphere protection, naturally cooling after insulation 10-40 min, obtain the spherical porous LiFePO 4 powder that carbon coats.
According to above-described preparation method, source of iron is ironic citrate (FeC specifically
6h
5o
7), or iron chloride (FeCl
3.6H
2or ferric nitrate [Fe (NO O),
3)
39H
2o], or ferric sulfate [Fe
2(SO
4)
3], or the combination of above source of iron material.
According to above-described preparation method, the organic molecule dispersant is citric acid specifically, or glutamic acid, or ascorbic acid, or tartaric acid, or salicylic acid, or above several combination.
According to above-described preparation method, surfactant is gelatin specifically, or polyethylene glycol, or polyvinyl alcohol, or ammonium polymethacrylate, or ammonium oleate, or ammonium alginate, or the combination of the above surfactant materials.
According to above-described preparation method, the lithium source is lithium carbonate (Li specifically
2cO
3), or lithium hydroxide (LiOH), or lithium dihydrogen phosphate (LiH
2pO
4), or the combination of the above lithium source substance.
According to above-described preparation method, the phosphorus source is diammonium hydrogen phosphate [(NH specifically
4)
2hPO
4], or ammonium dihydrogen phosphate (NH
4h
2pO
4), or lithium dihydrogen phosphate (LiH
2pO
4), or phosphoric acid (H
3pO
4), or the combination of the above phosphorus source material.
According to above-described preparation method, carbon source is 1-ethyl-3-methylimidazole nitrate [EMIm] NO specifically
3, or 1-butyl-3-methylimidazole nitrate [BMIm] NO
3, or 1-methyl imidazolium tetrafluoroborate [MIm] BF
4, or 1-ethyl imidazol(e) tetrafluoroborate [EIm] BF
4, or 1-methylimidazole dihydric phosphate [MIm] H
2pO
4, or 1-butyl imidazole dihydric phosphate [BIm] H
2pO
4, or 1-ethyl-3-methylimidazole dintrile amine [EMIm] N (CN)
2, or 1-butyl-3-methylimidazole dintrile amine [BMIm] N (CN)
2deng, or the combination of the above ionic liquid.
According to above-described preparation method, the doping metals compound is magnesium nitrate [Mg (NO specifically
3)
2.2H
2o], or magnesium oxalate [MgC
2o
4.2H
2o], or nickel nitrate [Ni (NO
3)
26H
2o], or nickel acetate [C
2h
3niO
2], or cobalt nitrate [Co (NO
3)
26H
2o], or cobalt acetate [C
4h
6o
4co4H
2o], or aluminum nitrate [Al (NO
3)
39H
2o], or the combination of the above doping metals compound.
Below in conjunction with the drawings and specific embodiments, the present invention is described further.
Embodiment 1:
According to stoichiometric proportion Li
0.99mg
0.01fePO
4at first take 27.03g iron chloride (FeCl
3.6H
2o), be dissolved in deionized water and be made into Fe
3+the solution of concentration 0.1mol/L, adopt the ammoniacal liquor of mass concentration 10% as precipitation reagent, and the 1.92g citric acid is dissolved in the 100mL deionized water as end liquid; By Fe
3+solution and precipitation reagent add end liquid simultaneously, regulate the addition of precipitation reagent and control pH=8.0 to Fe
2o
3.3H
2o precipitates fully; By after precipitate and separate, washing, under stirring, add the 0.01mol/L watery hydrochloric acid of 50mL to carry out acidifying, high speed centrifugation (4000r/min) adds in the 100mL deionized water after separating, add 0.08g ammonium oleate and 0.08g gelatin in deionized water, under 30 ℃, 600 rpm strong stirring 4h obtain Fe again
2o
3.3H
2the O colloid.Take 1.57g1-ethyl-3-methylimidazole nitrate, 2.37g lithium hydroxide and 0.26g magnesium nitrate.These materials are added to Fe
2o
3.3H
2in the O colloid, continue to stir 2h with 600rpm and obtain uniform gluey mixed slurry.Slurry spray-dried (130 ℃ of inlet temperatures) forms the spherical LiFePO 4 presoma.Presoma is put into crucible and is warming up to 500 ℃ at the microwave oven of nitrogen protection, is incubated after 20 min naturally coolingly, obtains the spherical porous LiFePO 4 powder that carbon coats, and granule-morphology as shown in Figure 2.
The battery performance test of gained lithium iron phosphate positive material all adopts the CR2025 button cell, in being full of the glove box of inert atmosphere, is assembled.Negative pole adopts metal lithium sheet, and electrolyte adopts 1mol.L
-liPF6/EC:DMC (1:1), wherein EC is ethylene carbonate, DMC is dimethyl carbonate.Positive plate preparation technology is as follows: by positive electrode and conductive agent acetylene black, the binding agent PVDF(polyvinylidene fluoride prepared) by 85:8:7, mix, add appropriate NMP(N-methyl pyrrolidone) in agate mortar, grind evenly, form the colloidal mixture of thickness, then be uniformly coated on the aluminium foil that 0.02mm is thick, be placed in 120 ℃ of vacuumize 20h, the battery assembled carries out charge-discharge performance and cycle performance test with blue electric battery test system.As shown in Figure 3, charge-discharge magnification is under the 2C condition, and material initial discharge specific capacity is 143.2mAh/g, through 50 circulation volume conservation rates 99.8%
Embodiment 2:
According to stoichiometric proportion Li
0.99mg
0.01fePO
4at first take 27.03g iron chloride (FeCl
3.6H
2o), be dissolved in deionized water and be made into Fe
3+the solution of concentration 0.1mol/L, adopt the ammoniacal liquor of mass concentration 10% as precipitation reagent, and the 1.92g citric acid is dissolved in the 100mL deionized water as end liquid; By Fe
3+solution and precipitation reagent add end liquid simultaneously, regulate the addition of precipitation reagent and control pH=8.0 to Fe
2o
3.3H
2o precipitates fully; By after precipitate and separate, washing, under stirring, add the 0.01mol/L watery hydrochloric acid of 50mL to carry out acidifying, high speed centrifugation (4000r/min) adds in the 100mL deionized water after separating, add 0.08g ammonium oleate and 0.08g polyethylene glycol in deionized water, under 30 ℃, 600 rpm strong stirring 4h obtain Fe again
2o
3.3H
2the O colloid.Take 1.57g1-ethyl-3-methylimidazole nitrate, 2.37g lithium hydroxide and 0.26g magnesium nitrate.These materials are added to Fe
2o
3.3H
2in the O colloid, continue to stir 2h with 600rpm and obtain uniform gluey mixed slurry.Slurry spray-dried (130 ℃ of inlet temperatures) forms the spherical LiFePO 4 presoma.Presoma is put into crucible and is warming up to 500 ℃ at the microwave oven of nitrogen protection, is incubated after 20 min naturally coolingly, obtains carbon and coats spherical porous calcium phosphate iron powder for lithium.
According to the method assembled battery of embodiment 1, to be tested, charge-discharge magnification is under the 2C condition, the material initial discharge capacity reaches 140.0mAh/g, through 50 circulation volume conservation rates 100%.
Embodiment 3:
According to stoichiometric proportion Li
0.99mg
0.01fePO
4at first take 27.03g iron chloride (FeCl
3.6H
2o), be dissolved in deionized water and be made into Fe
3+the solution of concentration 0.1mol/L, adopt the ammoniacal liquor of mass concentration 10% as precipitation reagent, and the 1.92g citric acid is dissolved in the 100mL deionized water as end liquid; By Fe
3+solution and precipitation reagent add end liquid simultaneously, regulate the addition of precipitation reagent and control pH=8.0 to Fe
2o
3.3H
2o precipitates fully; By after precipitate and separate, washing, under stirring, add the 0.01mol/L watery hydrochloric acid of 50mL to carry out acidifying, high speed centrifugation (4000r/min) adds in the 100mL deionized water after separating, add 0.08g ammonium oleate and 0.08g gelatin in deionized water, under 30 ℃, 600 rpm strong stirring 4h obtain Fe again
2o
3.3H
2the O colloid.Take 1.57g1-ethyl imidazol(e) tetrafluoroborate, 2.37g lithium hydroxide and 0.26g magnesium nitrate.These materials are added to Fe
2o
3.3H
2in the O colloid, continue to stir 2h with 600rpm and obtain uniform gluey mixed slurry.Slurry spray-dried (130 ℃ of inlet temperatures) forms the spherical LiFePO 4 presoma.Presoma is put into crucible and is warming up to 500 ℃ at the microwave oven of nitrogen protection, is incubated after 20 min naturally coolingly, obtains the spherical porous LiFePO 4 powder that carbon coats.
According to the method assembled battery of embodiment 1, to be tested, charge-discharge magnification is under the 2C condition, the material initial discharge capacity reaches 141.3mAh/g, through 50 circulation volume conservation rates 98.6%.
Embodiment 4:
According to stoichiometric proportion Li
0.99mg
0.01fePO
4at first take 27.03g iron chloride (FeCl
3.6H
2o), be dissolved in deionized water and be made into Fe
3+the solution of concentration 0.1mol/L, adopt the ammoniacal liquor of mass concentration 10% as precipitation reagent, and the 1.92g citric acid is dissolved in the 100mL deionized water as end liquid; By Fe
3+solution and precipitation reagent add end liquid simultaneously, regulate the addition of precipitation reagent and control pH=8.0 to Fe
2o
3.3H
2o precipitates fully; By after precipitate and separate, washing, under stirring, add the 0.01mol/L watery hydrochloric acid of 50mL to carry out acidifying, high speed centrifugation (4000r/min) adds in the 100mL deionized water after separating, add 0.08g ammonium oleate and 0.08g polyethylene glycol in deionized water, under 30 ℃, 600 rpm strong stirring 4h obtain Fe again
2o
3.3H
2the O colloid.Take 1.57g1-ethyl imidazol(e) tetrafluoroborate, 2.37g lithium hydroxide and 0.26g magnesium nitrate.These materials are added to Fe
2o
3.3H
2in the O colloid, continue to stir 2h with 600rpm and obtain uniform gluey mixed slurry.Slurry spray-dried (130 ℃ of inlet temperatures) forms the spherical LiFePO 4 presoma.Presoma is put into crucible and is warming up to 500 ℃ at the microwave oven of nitrogen protection, naturally cooling after insulation 20min, obtains carbon and coats spherical porous calcium phosphate iron powder for lithium.
According to the method assembled battery of embodiment 1, to be tested, charge-discharge magnification is under the 2C condition, the material initial discharge capacity reaches 138.3mAh/g, through 50 circulation volume conservation rates 99.2%.
Embodiment 5:
According to stoichiometric proportion Li
0.99mg
0.01fePO
4at first take 24.33g iron chloride (FeCl
3.6H
2o) and 2.45g ironic citrate (FeC
6h
5o
7) (mol ratio iron chloride: ironic citrate=9:1), be dissolved in deionized water and be made into Fe
3+the solution of concentration 0.1mol/L, adopt the ammoniacal liquor of mass concentration 10% as precipitation reagent, and 1.92g glutamic acid is dissolved in the 100mL deionized water as end liquid; By Fe
3+solution and precipitation reagent add end liquid simultaneously, regulate the addition of precipitation reagent and control pH=8.0 to Fe
2o
3.3H
2o precipitates fully; By after precipitate and separate, washing, under stirring, add the 0.01mol/L watery hydrochloric acid of 50mL to carry out acidifying, high speed centrifugation (4000r/min) adds in the 100mL deionized water after separating, add 0.08g ammonium oleate and 0.08g gelatin in deionized water, under 30 ℃, 600 rpm strong stirring 4h obtain Fe again
2o
3.3H
2the O colloid.Take 1.57g1-ethyl-3-methylimidazole nitrate, 2.37g lithium hydroxide and 0.26g magnesium nitrate.These materials are added to Fe
2o
3.3H
2in the O colloid, continue to stir 2h with 600rpm and obtain uniform gluey mixed slurry.Slurry spray-dried (130 ℃ of inlet temperatures) forms the spherical LiFePO 4 presoma.Presoma is put into crucible and is warming up to 500 ℃ at the microwave oven of nitrogen protection, is incubated after 20 min naturally coolingly, obtains the spherical porous LiFePO 4 powder that carbon coats.
According to the method assembled battery of embodiment 1, to be tested, charge-discharge magnification is under the 2C condition, the material initial discharge capacity reaches 138.3mAh/g, through 50 circulation volume conservation rates 99.8%.
Embodiment 6:
According to stoichiometric proportion Li
0.99mg
0.01fePO
4at first take 24.33g iron chloride (FeCl
3.6H
2o) and 2.45g ironic citrate (FeC
6h
5o
7) (mol ratio iron chloride: ironic citrate=9:1), be dissolved in deionized water and be made into Fe
3+the solution of concentration 0.1mol/L, adopt the ammoniacal liquor of mass concentration 10% as precipitation reagent, and 1.92g glutamic acid is dissolved in the 100mL deionized water as end liquid; By Fe
3+solution and precipitation reagent add end liquid simultaneously, regulate the addition of precipitation reagent and control pH=8.0 to Fe
2o
3.3H
2o precipitates fully; By after precipitate and separate, washing, under stirring, add the 0.01mol/L watery hydrochloric acid of 50mL to carry out acidifying, high speed centrifugation (4000r/min) adds in the 100mL deionized water after separating, add 0.08g ammonium oleate and 0.08g polyethylene glycol in deionized water, under 30 ℃, 600 rpm strong stirring 4h obtain Fe again
2o
3.3H
2the O colloid.Take 1.57g1-ethyl-3-methylimidazole nitrate, 2.37g lithium hydroxide and 0.26g magnesium nitrate.These materials are added to Fe
2o
3.3H
2in the O colloid, continue to stir 2h with 600rpm and obtain uniform gluey mixed slurry.Slurry spray-dried (130 ℃ of inlet temperatures) forms the spherical LiFePO 4 presoma.Presoma is put into crucible and is warming up to 500 ℃ at the microwave oven of nitrogen protection, is incubated after 20 min naturally coolingly, obtains the spherical porous LiFePO 4 powder that carbon coats.
According to the method assembled battery of embodiment 1, to be tested, charge-discharge magnification is under the 2C condition, the material initial discharge capacity reaches 143.1mAh/g, through 50 circulation volume conservation rates 98.4%.
Embodiment 7:
According to stoichiometric proportion Li
0.99mg
0.01fePO
4at first take 24.33g iron chloride (FeCl
3.6H
2o) and 2.45g ironic citrate (FeC
6h
5o
7) (mol ratio iron chloride: ironic citrate=9:1), be dissolved in deionized water and be made into Fe
3+the solution of concentration 0.1mol/L, adopt the ammoniacal liquor of mass concentration 10% as precipitation reagent, and 1.92g glutamic acid is dissolved in the 100mL deionized water as end liquid; By Fe
3+solution and precipitation reagent add end liquid simultaneously, regulate the addition of precipitation reagent and control pH=8.0 to Fe
2o
3.3H
2o precipitates fully; By after precipitate and separate, washing, under stirring, add the 0.01mol/L watery hydrochloric acid of 50mL to carry out acidifying, high speed centrifugation (4000r/min) adds in the 100mL deionized water after separating, add 0.08g ammonium oleate and 0.08g gelatin in deionized water, under 30 ℃, 600 rpm strong stirring 4h obtain Fe again
2o
3.3H
2the O colloid.Take 1.57g1-ethyl imidazol(e) tetrafluoroborate, 2.37g lithium hydroxide and 0.26g magnesium nitrate.These materials are added to Fe
2o
3.3H
2in the O colloid, continue to stir 2h with 600rpm and obtain uniform gluey mixed slurry.Slurry spray-dried (130 ℃ of inlet temperatures) forms the spherical LiFePO 4 presoma.Presoma is put into crucible and is warming up to 500 ℃ at the microwave oven of nitrogen protection, is incubated after 20 min naturally coolingly, obtains the spherical porous LiFePO 4 powder that carbon coats.
According to the method assembled battery of embodiment 1, to be tested, charge-discharge magnification is under the 2C condition, the material initial discharge capacity reaches 137.4mAh/g, through 50 circulation volume conservation rates 97.6%.
Embodiment 8:
According to stoichiometric proportion Li
0.99mg
0.01fePO
4at first take 24.33g iron chloride (FeCl
3.6H
2o) and 2.45g ironic citrate (FeC
6h
5o
7) (mol ratio iron chloride: ironic citrate=9:1), be dissolved in deionized water and be made into Fe
3+the solution of concentration 0.1mol/L, adopt the ammoniacal liquor of mass concentration 10% as precipitation reagent, and 1.92g glutamic acid is dissolved in the 100mL deionized water as end liquid; By Fe
3+solution and precipitation reagent add end liquid simultaneously, regulate the addition of precipitation reagent and control pH=8.0 to Fe
2o
3.3H
2o precipitates fully; By after precipitate and separate, washing, under stirring, add the 0.01mol/L watery hydrochloric acid of 50mL to carry out acidifying, high speed centrifugation (4000r/min) adds in the 100mL deionized water after separating, add 0.08g ammonium oleate and 0.08g polyethylene glycol in deionized water, under 30 ℃, 600 rpm strong stirring 4h obtain Fe again
2o
3.3H
2the O colloid.Take 1.57g1-ethyl imidazol(e) tetrafluoroborate, 2.37g lithium hydroxide and 0.26g magnesium nitrate.These materials are added to Fe
2o
3.3H
2in the O colloid, continue to stir 2h with 600rpm and obtain uniform gluey mixed slurry.Slurry spray-dried (130 ℃ of inlet temperatures) forms the spherical LiFePO 4 presoma.Presoma is put into crucible and is warming up to 500 ℃ at the microwave oven of nitrogen protection, is incubated after 20 min naturally coolingly, obtains carbon and coats spherical porous calcium phosphate iron powder for lithium.
According to the method assembled battery of embodiment 1, to be tested, charge-discharge magnification is under the 2C condition, material initial discharge capacity 139.6mAh/g, through 50 circulation volume conservation rates 96.8%.