Cobalt nickel series lithium ion battery positive electrode and its preparation method and application
Technical field
The present invention relates to technical field of lithium ion, relate generally to anode material for lithium ion battery field, specifically relate to
And a kind of cobalt nickel series lithium ion battery positive electrode and its preparation method and application.
Background technique
Increase and mobile phone, laptop, digital camera, camera shooting with the information age to battery new material demand
The energy source and powers such as the electronic products such as machine and electric car, electric tool product to novel, efficient, environment-friendly battery solid demand,
Lithium ion battery material market constantly expands.The positive electrode component part important as lithium battery, the quality of performance is directly
The properties of battery are influenced, anode material for lithium-ion batteries common at present mainly has cobalt acid lithium, LiMn2O4, nickle cobalt lithium manganate
And LiFePO 4.Wherein cobalt acid lithium is because cobalt storage capacity is limited and safety reasons are mainly used for 3C small-scale lithium ion cell neck
Domain, LiMn2O4 and ferrousphosphate lithium material energy density are lower, have and are gradually replaced by the low nickel-containing material containing cobalt such as nickle cobalt lithium manganate
The trend in generation.
Cobalt nickel binary and Co-Ni-Mn ternary material (being referred to as nickel cobalt or cobalt nickel system positive electrode) are usually stratiform rock salt
The content of structural material, nickel and manganese element can be high or low, and manganese can be replaced completely by nickel.Wherein, cobalt (Co) is positive electrode
One of main structural elements, cobalt and cobalt compound conductivity are high, therefore can improve the discharge capacity and high-multiplying power discharge of material
Performance.Nickel (Ni) is also one of the main active substances of material, the capacity of material can be improved, but Ni valence state is changeable, is being circulated throughout
Capacitance loss is big in journey.Manganese (Mn) good electrochemicaUy inert, can make material remain stable structure.
The performance of Ni-Co series positive electrode is closely related with preparation method, and there are many preparation method, such as high temperature solid-state method, altogether
The precipitation method, sol-gal process, spray pyrolysis etc..High temperature solid-state method is to prepare positive electrode a kind of commonly method at present, will
Raw material is directly mixed in solid form, in high―temperature nuclei.High temperature solid-state method simple process is suitble to large-scale production, but very
It is uniform to be difficult to guarantee mixing, causes that product batches consistency is poor, chemical property is unstable;Coprecipitation is chemical raw material with molten
Liquid status mixing, and precipitating reagent appropriate is added into solution, make each component in solution by evenly mixing based on chemistry
Amount ratio is co-precipitated out, or first reaction is settled out a kind of intermediate product in the solution, prepares positive electrode using calcining.
Coprecipitation can pattern to cobalt nickel system presoma and granularity control, be conducive to obtain shape with after lithium source high temperature process heat
Looks, partial size, density stabilized material are to prepare the most important method of Ni-Co series positive electrode at present, but adopt in process of production
It is high with conventional multi-step sintering process energy consumption, and during by lithium source and baking mixed nickel cobalt hydroxide precursor, by
In a kind of lithium source also macroscopic particles object, the contact area of lithium source and predecessor and it has been unevenly distributed in diffusion process
It is likely to result in the uneven of material surface part lithium source, causes free lithium content high, was equally coated in progress surface doping
Doped chemical will permeate/be diffused into positive electrode surface and body phase that there is also identical problems in journey, need to try thus to solve
Certainly lithium source, doped chemical persursor material surface distribution and diffusion problem;Sol-gal process complex process, higher cost,
The pattern and partial size of product are not easy to control;Spray pyrolysis is currently limited to experimental study, is not able to achieve industrialization.
Summary of the invention
Problem of the existing technology is: in existing cobalt nickel system positive electrode preparation process, high temperature solid-state method preparation
Product batches consistency is poor, chemical property is unstable due to causing it is difficult to ensure that mixing is uniform for positive electrode, is co-precipitated legal system
There are lithium sources and doped chemical to spread non-uniform problem for standby positive electrode, and the lithium content that dissociates is high, and in process of production
The sintering process energy consumption for preparing presoma is high, and the lithium ion battery security prepared is poor.
In order to solve the above technical problems, inventor, after analyzing cobalt nickel system positive electrode preparation process, discovery is solid in high temperature
During phase method prepares positive electrode, raw material is not mixed in solid form, and first by raw material in water and/or isopropanol solvent
Stirring can be such that feed components are uniformly mixed, but during being subsequently dried evaporation solvent due to concentration and diffusion velocity not
Together, still mixing is uneven for the cobalt nickel raw material composition after leading to drying, and chemical property is unstable.Therefore, inventor is creative
The mixed liquor of external adding water and acidic materials after raw material physical mixed carries out to chemical homogeneous mixing at normal temperature, acid is added
The purpose of matter is by each raw material surface dissolution/reaction so that its mixing more evenly, while inhibiting to cause in solvent evaporation process
Mixing it is uneven, inventor by control mixed liquor in water/acidic materials ratio and the additional amount of mixed liquor, finally in height
The cobalt nickel series lithium ion battery positive electrode that raw material is uniformly mixed, external and internal compositions lithium is uniform is generated under temperature sintering, has reached and has mentioned
The purpose of the energy density of lithium ion battery, chemical property and security performance is risen, while being just added and mixing in the mixing raw materials stage
Miscellaneous element, can form the dopant being evenly distributed, and further improve lithium ion battery chemical property.
Specifically, the present invention provides the following technical scheme that
A kind of cobalt nickel series lithium ion battery positive electrode, chemical general formula are as follows: LixCoaNibR(1-a-b)O2, in which: R is to mix
Miscellaneous element, R are selected from Mn, Y, Mg and/or Al, 0.9≤x≤1.1,0.55≤a≤0.9,0.05≤b≤0.4,0.7≤a+b≤1;
Wherein, the average aspect ratio of the positive electrode is 1.5-3.0.
Preferably, in above-mentioned positive electrode, the average aspect ratio of the positive electrode is 1.7-2.5.
Preferably, in above-mentioned positive electrode, the pole piece compaction density of the positive electrode is greater than 3.6g/cm3, preferably
3.6-4.3g/cm3。
Preferably, in above-mentioned positive electrode, the positive electrode by containing Li source compound, cobalt source compound,
The mixing of acidic materials and solvent composition is added in the raw material of nickel source compound and the doping element compound being added as needed
After liquid, through drying, it is sintered.
Preferably, in above-mentioned positive electrode, the mass ratio of the mixed liquor and raw material is 20~200:100, preferably
26-71:100。
Preferably, in above-mentioned positive electrode, the solvent is deionized water and/or isopropanol, acid in the mixed liquor
Property substance and solvent mass ratio be 0.4-4:1, preferably 0.75-2.5:1.
Preferably, in above-mentioned positive electrode, the acidic materials are carboxylic acid, preferably formic acid, acetic acid, adipic acid or lemon
The one or more of lemon acid, more preferably acetic acid.
Preferably, in above-mentioned positive electrode, the Li source compound be selected from monohydrate lithium hydroxide, lithium oxalate, lithium carbonate,
One or more of lithium acetate, tert-butyl alcohol lithium or lithium citrate.
Preferably, in above-mentioned positive electrode, the cobalt source compound is selected from cobalt carbonate (II), cobalt hydroxide (II) or oxygen
Change the one or more of cobalt (II).
Preferably, in above-mentioned positive electrode, the nickel source compound is selected from nickelous carbonate (II), nickel hydroxide (II) or oxygen
Change the one or more of nickel (II).
Preferably, in above-mentioned positive electrode, the doping element compound is selected from salt, the hydroxide of manganese, yttrium, magnesium or aluminium
The one or more of object, oxide or organic matter.
The present invention also provides the preparation methods of above-mentioned positive electrode, include the following steps:
Li source compound, cobalt source compound, nickel source compound and the doping element compound that is added as needed will be contained
Raw material by metering than carry out mixing, then be added acidic materials further mixed with the mixed liquor that solvent forms, through drying, burning
Knot obtains cobalt nickel series lithium ion battery positive electrode.
Preferably, in above-mentioned preparation method, the drying temperature is 40~150 DEG C, it is preferred that drying pressure is vacuum
7-100kPa is spent, it is furthermore preferred that drying time is 1.5~10h.
Preferably, in above-mentioned preparation method, the sintering temperature is 880-950 DEG C, it is preferred that sintering time 10-
20h, it is furthermore preferred that sintering atmosphere is to have oxygen atmosphere.
The present invention also provides a kind of lithium ion batteries, and it includes above-mentioned positive electrodes.
The present invention also provides above-mentioned positive electrode or lithium ion battery lithium electric energy source domain application, preferably in movement
The application of communication apparatus, electric automobiles.
Beneficial effects of the present invention:
(1) present invention carries out the mixed liquor of external adding water and acidic materials after the raw material physical mixed of cobalt nickel system positive electrode
Chemical homogeneous mixing, and anode material for lithium ion battery is ultimately generated under high temperature sintering, which is uniformly mixed, is interior
External structure lithium is uniform, has achieved the purpose that the energy density, chemical property and the security performance that promote lithium ion battery,
(2) doped chemical is just added in raw material mix stages in cobalt nickel system's positive electrode of the invention, can be formed uniform
Dopant, solves the problems, such as uneven doped elements, further improves lithium ion battery chemical property, eliminates additional
Doping process.
(3) cobalt nickel system positive electrode of the invention eliminates precursor preparation technique, and energy saving has preferable application
Prospect.
Detailed description of the invention
Fig. 1-a be 1 positive electrode of embodiment scanning electron microscope (SEM) photograph, 3000 times of amplification factor.
Fig. 1-b be 1 positive electrode of comparative example scanning electron microscope (SEM) photograph, 3000 times of amplification factor.
Fig. 1-c be 2 positive electrode of embodiment scanning electron microscope (SEM) photograph, 3000 times of amplification factor.
Fig. 1-d be 2 positive electrode of comparative example scanning electron microscope (SEM) photograph, 3000 times of amplification factor.
60 DEG C of 0.5C/ of cylindrical battery that Fig. 2 is embodiment 4, prepared by embodiment 5, comparative example 4,5 positive electrode of comparative example
0.5C recycles result.Wherein, 2-a, 2-b, 2-c, 2-d respectively correspond embodiment 4, embodiment 5, comparative example 4, described in comparative example 5
Positive electrode.
Fig. 3 is the cylindrical battery pinning experiment typical figure of embodiment 5, the preparation of 5 positive electrode of comparative example.Wherein, 3-a is pair
5 sting test result of ratio, Fig. 3-b are 5 sting test result of embodiment.
Fig. 4 is the battery charging and discharging curve of 4 positive electrode of embodiment preparation.
Specific embodiment
In existing Ni-Co series positive electrode preparation process, the positive electrode of high temperature solid-state method preparation is due to it is difficult to ensure that mixed
Material uniformly, causes that product batches consistency is poor, chemical property is unstable, the positive electrode of coprecipitation preparation there are lithium source with
Doped chemical spreads non-uniform problem, and the lithium content that dissociates is high, and prepares the sintering process energy of presoma in process of production
Consumption is high, and the lithium ion battery security prepared is poor.In consideration of it, the present invention provides a kind of cobalt nickel series lithium ion battery anode materials
Material, chemical general formula are as follows: LixCoaNibR(1-a-b)O2, in which: R is doped chemical, and R is selected from Mn, Y, Mg and/or Al, 0.9≤x≤
1.1,0.55≤a≤0.9,0.05≤b≤0.4,0.7≤a+b≤1;Wherein, the average aspect ratio of the positive electrode is 1.5-
3.0。
In positive electrode of the invention, the Co and Ni are chief active structural materials, pass through the chemical valence in charge and discharge
Variation the stable reversible crystal structure of positive electrode is provided, realize the charge and discharge cycles of lithium ion battery, the doped chemical
Selected from Mn, Y, Mg and/or Al, main function is the further structure for stablizing positive electrode, and improves positive electrode and electricity
Solve the contact of matter.
In a preferred embodiment of the invention, the average aspect ratio of the positive electrode is 1.7-2.5.
In a preferred embodiment of the invention, the pole piece compaction density of the positive electrode is greater than 3.6g/
cm3, preferably 3.6-4.3g/cm3。
In a preferred embodiment of the invention, above-mentioned positive electrode by contain Li source compound, cobalt source
Acidic materials are added in the raw material of compound, nickel source compound and the doping element compound being added as needed and solvent forms
Mixed liquor after, through drying, be sintered.
Wherein, the mass ratio of above-mentioned mixed liquor and raw material is 20~200:100, preferably 26-71:100.
Wherein, above-mentioned solvent is deionized water and/or isopropanol, the mass ratio of above-mentioned mixed liquor middle acid substance and solvent
For 0.4-4:1, preferably 0.75-2.5:1.
Wherein, above-mentioned acidic materials are carboxylic acid, preferably formic acid, acetic acid, adipic acid or citric acid it is one or two kinds of with
On, more preferably acetic acid.
Wherein, above-mentioned Li source compound is selected from monohydrate lithium hydroxide, lithium oxalate, lithium carbonate, lithium acetate, tert-butyl alcohol lithium or lemon
One or more of lemon acid lithium.
Wherein, above-mentioned cobalt source compound is selected from one kind or two of cobalt carbonate (II), cobalt hydroxide (II) or cobalt oxide (II)
Kind or more.
Wherein, above-mentioned nickel source compound is selected from one kind or two of nickelous carbonate (II), nickel hydroxide (II) or nickel oxide (II)
Kind or more.
Wherein, above-mentioned doping element compound is selected from manganese, yttrium, the salt of magnesium or aluminium, hydroxide, oxide or organic matter
It is one or more kinds of.
In a preferred embodiment of the invention, the preparation method of above-mentioned positive electrode, includes the following steps:
A) ingredient.By Li source compound, cobalt source compound, nickel source compound and the doped chemical that is added as needed
Conjunction object weighing, which is added in dispersing apparatus, to be mixed, after the mixed liquor of acidic materials and solvent composition is then added into mixed material
Be dispersed with stirring uniformly, finely dispersed material is added in drying equipment, is warming up to 40~150 DEG C, vacuum degree be 7~
It is dried in vacuo 1.5~10h under 100Kpa, fluffy dry powder is prepared.
B) it is sintered.The dry powder of a) preparation is fitted into ceramic alms bowl and is put into sintering furnace, oxygen-enriched air condition is being passed through
Under, after being warming up to 880-950 DEG C of high temperature sintering 10-20h with 5-15 DEG C/min, cooling discharge.
C) it crushes.The material of b) preparation is crushed using pulverizer to get object of the present invention is arrived.
The present invention also provides a kind of lithium ion batteries, and it includes above-mentioned cobalt nickel series lithium ion batteries to be made of positive electrode
Electrode.
The present invention also provides above-mentioned positive electrodes or lithium ion battery in the application of lithium electric energy source domain, preferably leads to mobile
Interrogate the application of equipment, electric automobiles.
The present invention is described in further detail with comparative example combined with specific embodiments below.
Used reagent and device information are as shown in table 1 and table 2 in embodiment and comparative example.
Agents useful for same information in 1 embodiment of the present invention of table and comparative example
Instrument information in 2 embodiment of the present invention of table and comparative example
Embodiment 1
It weighs 117.4kg cobalt carbonate (II), 6.4kg nickelous carbonate (II), 12.7kg yttrium nitrate hexahydrate, 1.6kg nanometers of hydrogen-oxygens
Change aluminium, 69.1kg lithium carbonate is added in the high speed disperser of liner tungsten carbide and is uniformly mixed, while weighing 30.0kg deionization
The mixed liquor of water and 12.0kg formic acid is slowly added into the high speed disperser of liner tungsten carbide, and high speed dispersion is until temperature is lower than
30 DEG C, using rotary vacuum dryer, 40 DEG C of vacuum drying 10h are warming up to after the slurry of above-mentioned preparation is put into, vacuum degree is
8kPa obtains fluffy powdery grey material.
Using ventilation 24m roller kilns, setting heating zone temperature is 930 DEG C, is passed through (oxygen content volume under the conditions of oxygen-enriched air
Than being 60%, gas input 600m3/ h), the material of above-mentioned drying is fitted into feeding roller-way in ceramic alms bowl and is sintered, is sintered
Time is 12h, and material air-isolation is cooled to room temperature, and weighs the weight of disengaging material, counts burn tinctuer (sintering powder quality
Difference and the ratio for being sintered preceding powder quality) it is 51.2%.Then it is crushed with micronizer, obtains cobalt nickel system anode material
Material.
It is detected through laser particle size analyzer, the granularity (D for the positive electrode that the present embodiment is preparedv50) it is 10.2 μm;Through
Electron microscope (SEM) observation counts, and the average aspect ratio of particulate matter is 3.0 in the positive electrode that the present embodiment is prepared;Through than
The detection of surface area tester, the positive electrode specific surface area that the present embodiment is prepared are 0.25m2/g。
With ICP to the results are shown in Table 3 after the quantitative elementary analysis of positive electrode, just according to the available preparation of table 3
Pole material structure formula are as follows: Li0.95Co0.90Ni0.05Al0.02Y0.03O2。
Positive electrode element characterization result described in 3 embodiment 1 of table
Element |
Li |
Co |
Ni |
Mn |
Al |
Ca |
Mg |
Mass ratio |
6.595 |
53.04 |
2.35 |
0.007 |
0.0548 |
0.0020 |
0.0024 |
Atomic weight |
6.94 |
58.93 |
58.69 |
54.94 |
26.98 |
40.00 |
24.00 |
Molal quantity |
0.95 |
0.90 |
0.048 |
0.0001 |
0.02 |
0.00005 |
0.00010 |
Element |
Na |
P |
S |
Ti |
Y |
Zn |
Zr |
Mass ratio |
0.0037 |
0.0047 |
0.0547 |
0.0398 |
2.67 |
0.0000 |
0.0023 |
Atomic weight |
23.00 |
30.97 |
32.00 |
40.00 |
88.91 |
65.41 |
91.22 |
Molal quantity |
0.00016 |
0.00015 |
0.00171 |
0.0001 |
0.03 |
0.00000 |
0.00003 |
Embodiment 2
It weighs 71.4kg cobalt carbonate (II), 52.8kg nickelous carbonate (II), 0.2kg manganese oxalate dihydrate (II), 0.4kg oxidation
Magnesium, 75.7kg lithium carbonate are added in plough type batch mixer and are uniformly mixed, while weighing the mixed of 80kg deionized water and 320kg acetic acid
It closes liquid to be slowly added into plough type batch mixer, high speed dispersion is lower than 30 DEG C up to temperature, will be upper using rotary vacuum dryer
State preparation slurry be put into after be warming up to 150 DEG C of vacuum drying 1.5h, vacuum degree 86kPa, fluffy powdery gray is made
Expect spare.
Using ventilation 24m roller kilns.It is 880 DEG C that heating zone temperature, which is arranged, is passed through (oxygen content volume under the conditions of oxygen-enriched air
Than being 60%, gas input 500m3/ h), the material of above-mentioned drying is fitted into feeding roller-way in ceramic alms bowl and is sintered, is sintered
Time is 16h, and material air-isolation is cooled to room temperature, and weighs the weight of disengaging material, counts burn tinctuer (sintering powder quality
Difference and the ratio for being sintered preceding powder quality) it is 49.2%.Then it is crushed with cyclone vortex pulverizer, obtains cobalt nickel system anode
Material.
Through detecting, the granularity (D for the positive electrode that the present embodiment is preparedv50) it is 7.0 μm, the average major diameter of particulate matter
Than being 1.5, specific surface area 0.5m2/g。
With ICP to the multivariate solid solution structural formula synthesized after the quantitative elementary analysis of positive electrode are as follows: Li1.01Co0.5 5Ni0.39Mn0.05Mg0.01O2。
Positive electrode element characterization result described in 4 embodiment 2 of table
Element |
Li |
Co |
Ni |
Mn |
Al |
Ca |
Mg |
Mass ratio |
7.01 |
32.62 |
23.15 |
2.69 |
0.0021 |
0.0020 |
0.29 |
Atomic weight |
6.94 |
58.93 |
58.69 |
54.94 |
26.98 |
40.00 |
24.00 |
Molal quantity |
1.01 |
0.55 |
0.39 |
0.049 |
/ |
/ |
0.012 |
Element |
Na |
P |
S |
Ti |
Y |
Zn |
Zr |
Mass ratio |
0.0091 |
0.0027 |
0.0469 |
0.0086 |
0.0004 |
0.0000 |
0.0033 |
Atomic weight |
23.00 |
30.97 |
32.00 |
40.00 |
88.91 |
65.41 |
91.22 |
Molal quantity |
/ |
/ |
0.0015 |
/ |
/ |
/ |
/ |
Embodiment 3
It weighs 103.5kg cobalt carbonate (II), 19.7kg nickelous carbonate (II), 3.3kg nano-aluminum hydroxide, 76.2kg lithium carbonate
It is added in plough type batch mixer and is uniformly mixed, weigh about 30kg adipic acid, 30kg citric acid and 40kg deionized water, and
40kg isopropanol is configured to mixed liquor, is slowly added into plough type batch mixer under stirring, is warming up to 60 DEG C, is dispersed with stirring
60min then heats to 110 DEG C of vacuum drying 4h, vacuum using rotary vacuum dryer after being put into the slurry of above-mentioned preparation
Degree is 98kPa, and it is spare that fluffy powdery grey material is made.
Using ventilation 24m roller kilns.It is 920 DEG C that heating zone temperature, which is arranged, is passed through (oxygen content volume under the conditions of oxygen-enriched air
Than being 80%, gas input 300Nm3/ h), the material of above-mentioned drying is fitted into feeding roller-way in ceramic alms bowl and is sintered, is burnt
The knot time is 16h, and material air-isolation is cooled to room temperature, and weighs the weight of disengaging material, counts burn tinctuer (sintering powder matter
Amount difference and the ratio for being sintered preceding powder quality) it is 51.1%.Then it is crushed with cyclone vortex pulverizer, is obtaining cobalt nickel system just
Pole material.
Through detecting, the granularity (D for the positive electrode that the present embodiment is preparedv50) it is 9.0 μm, the average major diameter of particulate matter
Than being 2.2, specific surface area 0.3m2/g。
With ICP to the multivariate solid solution structural formula synthesized after the quantitative elementary analysis of positive electrode are as follows:
Li1.02Co0.8Ni0.15Al0.05O2。
Embodiment 4
It weighs 85.7kg cobalt carbonate (II), 14.7kg nickel hydroxide (II), 5.5kg magnesia, 71.4kg lithium carbonate is added
It is uniformly mixed into the high speed disperser of liner tungsten carbide, while the mixed liquor for weighing 36kg isopropanol and 90kg acetic acid slowly adds
Enter into high speed disperser, high speed dispersion is until temperature is lower than 30 DEG C.Using rotary vacuum dryer, by the slurry of above-mentioned preparation
It is warming up to 110 DEG C of vacuum drying 3.0h, vacuum degree 7kPa after being put into, it is spare to be dried into fluffy powdery grey material.
Using ventilation 24m roller kilns.It is 950 DEG C that heating zone temperature, which is arranged, is passed through (oxygen content volume under the conditions of oxygen-enriched air
Than being 80%, gas input 420Nm3/ h), the material of above-mentioned drying is fitted into feeding roller-way in ceramic alms bowl and is sintered, is burnt
The knot time is 10h, and material air-isolation is cooled to room temperature, and weighs the weight of disengaging material, counts burn tinctuer (sintering powder matter
Amount difference and the ratio for being sintered preceding powder quality) it is 60.5%.Then it is crushed with cyclone vortex pulverizer, is obtaining cobalt nickel system just
Pole material.
Through detecting, the granularity (D for the positive electrode that the present embodiment is preparedv50) it is 11.0 μm, the average major diameter of particulate matter
Than being 2.5, specific surface area 0.2m2/g。
With ICP to the multivariate solid solution structural formula synthesized after the quantitative elementary analysis of positive electrode are as follows:
Li1.01Co0.70Ni0.15Mg0.15O2。
Embodiment 5
It weighs 87.1kg cobalt carbonate (II), 19.0kg nickelous carbonate (II), 12.2kg magnesium carbonate, 28.6kg monohydrate lithium hydroxide
It is added in the high speed disperser of liner tungsten carbide and is uniformly mixed, while weighing 9.2kg water, 8.2kg isopropanol and 21.2Kg second
The mixed liquor of acid is slowly added into high speed disperser, and high speed dispersion is until temperature is lower than 30 DEG C.Using rotary vacuum dryer,
It is warming up to 110 DEG C of vacuum drying 4h, vacuum degree 8kPa after the material of above-mentioned preparation is put into, obtains fluffy powdery grey material
It is spare.
Using 24m ventilation pushed bat kiln.It is 920 DEG C that heating zone temperature, which is arranged, is passed through (oxygen content volume under the conditions of oxygen-enriched air
Than being 80%, gas input 500Nm3/ h), the material of above-mentioned drying is fitted into feeding kiln in ceramic alms bowl and is sintered, is burnt
The knot time is 20h, and material air-isolation is cooled to room temperature, and weighs the weight of disengaging material, counts burn tinctuer (sintering powder matter
Amount difference and the ratio for being sintered preceding powder quality) it is 32.2%.Then it is crushed with cyclone vortex pulverizer, is obtaining cobalt nickel system just
Pole material.
Through detecting, the granularity (D for the positive electrode that the present embodiment is preparedv50) it is 9.6 μm, the average major diameter of particulate matter
Than being 1.7, specific surface area 0.4m2/g。
With ICP to the multivariate solid solution structural formula synthesized after the quantitative elementary analysis of positive electrode are as follows:
Li1.04Co0.70Ni0.15Mg0.15O2。
Comparative example 1
By commercially available presoma Co0.90Ni0.05Al0.02Y0.03(OH)2It weighs 95.4kg to be added in high speed disperser, add
It weighs 37.9kg lithium carbonate to mix in high speed disperser, prepares cobalt nickel system anode material by preparation condition same as Example 1
Material, statistics burn tinctuer (the sintering powder ratio of poor quality with powder quality before sintering) is 25.2%.
Through detecting, cobalt nickel system positive electrode granularity (D that comparative example 1 obtainsv50) it is 19.2 μm, the average major diameter of particulate matter
Than being 4.0, specific surface area 0.4m2/g。
With ICP to the multivariate solid solution structural formula synthesized after the quantitative elementary analysis of positive electrode are as follows:
Li0.95Co0.90Ni0.05Al0.02Y0.03O2。
Comparative example 2
By commercially available presoma Co0.55Ni0.39Mn0.05Mg0.01(OH)289.9kg is weighed to be added in plough type batch mixer, then
44.3kg monohydrate lithium hydroxide is added to mix in plough type batch mixer, prepares cobalt nickel by preparation condition same as Example 2
It is positive electrode, statistics burn tinctuer (the sintering powder ratio of poor quality with powder quality before sintering) is 25.6%.
Through detecting, Ni-Co series positive electrode granularity (D that comparative example 2 obtainsv50) it is 6.7 μm, the average aspect ratio of particulate matter
It is 1.0, specific surface area 0.6m2/g。
With ICP to the multivariate solid solution structural formula synthesized after the quantitative elementary analysis of positive electrode are as follows: Li1.01Co0.5 5Ni0.39Mn0.05Mg0.01O2。
Comparative example 3
Comparative example 3 is identical with preparation method with the raw material of the embodiment of the present invention 3, and difference is only that, the mixed liquor of comparative example 3
For 15kg adipic acid, 15kg citric acid, 2kg deionized water and 3kg isopropanol.
Through detecting, the granularity (D for the cobalt nickel system positive electrode that comparative example 3 obtainsv50) it is 9.3 μm, the average major diameter of particulate matter
Than being 1.1, specific surface area 0.4m2/g。
With ICP to the multivariate solid solution structural formula synthesized after the quantitative elementary analysis of positive electrode are as follows:
Li1.02Co0.8Ni0.15Al0.05O2。
Comparative example 4
Comparative example 4 is identical as 4 raw material of the embodiment of the present invention and preparation method, and difference is only that, the mixed liquor of comparative example 4 is
270kg isopropanol and 90kg acetic acid.
Through detecting, the granularity (D for the cobalt nickel system positive electrode that comparative example 4 obtainsv50) it is 7.5 μm, the average major diameter of particulate matter
Than being 1.3, specific surface area 1.32m2/g。
With ICP to the multivariate solid solution structural formula synthesized after the quantitative elementary analysis of positive electrode are as follows:
Li1.01Co0.70Ni0.15Mg0.15O2。
Comparative example 5
Comparative example 5 is identical with preparation method with the raw material of the embodiment of the present invention 5, and difference is only that, the mixed liquor of comparative example 5
In be not added with water.
Through detecting, cobalt nickel system positive electrode granularity (D that comparative example 5 obtainsv50) it is 8.9 μm, the average aspect ratio of particulate matter
It is 1.1, specific surface area 0.3m2/g。
With ICP to the multivariate solid solution structural formula synthesized after the quantitative elementary analysis of positive electrode are as follows:
Li1.04Co0.70Ni0.15Mg0.15O2。
Positive electrode element characterization result described in 5 comparative example 5 of table
Element |
Li |
Co |
Ni |
Mn |
Al |
Ca |
Mg |
Mass ratio |
7.21 |
41.72 |
9.27 |
0.007 |
0.0020 |
0.0025 |
3.58 |
Atomic weight |
6.94 |
58.93 |
58.69 |
54.94 |
26.98 |
40.00 |
24.00 |
Molal quantity |
1.04 |
0.708 |
0.158 |
/ |
/ |
/ |
0.149 |
Element |
Na |
P |
S |
Ti |
Y |
Zn |
Zr |
Mass ratio |
0.0068 |
0.0028 |
0.0462 |
0.0057 |
0.003 |
0.0000 |
0.000 |
Atomic weight |
23.00 |
30.97 |
32.00 |
40.00 |
88.91 |
65.41 |
91.22 |
Molal quantity |
/ |
/ |
0.0014 |
/ |
/ |
/ |
/ |
Positive electrode prepared by above-described embodiment and comparative example is subjected to following characterizations:
1, scanning electron microscope sem figure
The positive electrode powder that above-described embodiment 1, comparative example 1, embodiment 2 and comparative example 2 are prepared is carried out respectively
Scanning electron microscope sem tests (amplification factor Mag=3.00KX, ZEISS), obtains Fig. 1-a, 1-b, 1-c, the result of 1-d.
By Fig. 1-a, 1-b is as it can be seen that the partial size of comparative example 1 is much bigger compared with embodiment 1, and surface is relatively rough, 1 table of embodiment
Face has uniformly coated one layer of light substance, and particle surface is smooth, and ball-type degree is good.
By Fig. 1-c, as it can be seen that there are many small particles between 2 particle of comparative example, same partial size is big compared with embodiment 2 to be obtained 1-d
More, embodiment 2 still remains secondary spherical granule-morphology, shows the positive electrode particle growth differences using this method preparation
Change is inhibited, and particle ball-type degree is more preferable, more evenly.Be conducive to the promotion of the performance of lithium-ion secondary battery of later period preparation.
2, free lithium and pH value
The each about 50g of positive electrode prepared by Example 1, embodiment 2, comparative example 1, comparative example 2, using leaching titration
Test the free lithium content and pH value in contrivance.Concrete operations are as follows: taking 50g positive electrode, (code name m, unit g) are added about
100g deionized water stirs 30min on magnetic stirring apparatus, then is filtered and filtered with filter paper, weighs 50ml liquid with pipette (50ml)
Body is put into the 100ml beaker with magnetic stirring apparatus.It places the beaker and is lined on the autotitrator of white circular filter paper, drip
Add 2 drop phenolphthalein indicators (0.1g/L ethanol solution), usually solution pinkiness at this time.
Start to titrate with normal hydrochloric acid liquid (0.049mol/L, code name C, unit mol/L), when solution becomes nothing from red
Color records the hydrochloric acid solution volume V of consumption1(unit: ml).2 drop methyl reds are added dropwise into solution again, and (0.1g/L dehydrated alcohol is molten
Liquid) indicator, continues to titrate hydrochloric acid solution, until the color of solution becomes orange from yellow.
It takes out beaker and carries out boiling heating, the carbon dioxide generated in solution is evaporated, solution returns again after cooling
In yellow.It removes after beaker is cooled to room temperature (23 ± 2 DEG C) and is further continued for titration solution, when solution becomes pale red from yellow,
Record the volume V of hydrochloric acid standard solution2(unit: ml).Leaching liquid is converted into positive electrode dissociate lithium carbonate and lithium hydroxide
Content calculation formula is as follows.
Li2CO3(wt%)=(V2-V1)*C*73.886*2*100/1000/m
LiOH (wt%)=[V2-2*(V2-V1)]*C*23.946*2*100/1000/m
Li+(wt%)=V2*C*6.94*2*100/m/1000
With reference to GB/T 9724-2007,5g embodiment sample is added the 45g deionized water of metering, is stirred with clean magnetic agitation
30min is mixed, then time of repose 90min is filtered with filter paper, takes pH of clear filtrate under the conditions of 23 ± 2 DEG C with pH meter detection filtrate
Value, obtains the pH value of embodiment powder, the results are shown in Table 6 for the free lithium and pH value of above-described embodiment.
The free lithium content of 6 embodiment of table and pH test result
Embodiment |
Lithium hydroxide |
Lithium carbonate |
Always free lithium |
PH value |
Unit |
(wt%) |
(wt%) |
(wt%) |
--- |
Embodiment 1 |
0.0300 |
0.0100 |
0.0100 |
10.31 |
Embodiment 2 |
0.0377 |
0.0737 |
0.0435 |
10.27 |
Comparative example 1 |
0.1671 |
0.0428 |
0.2330 |
10.65 |
Comparative example 2 |
0.0847 |
0.0930 |
0.0985 |
10.75 |
By table 6 as it can be seen that embodiment 1, the residual lithium of embodiment 2 and pH value are below the testing result of comparative example 1-2, usually
Residual lithium, which refers to, not exclusively leads to remaining lithium compound in solid powder surfaces and particle because reacting, usually with lithium hydroxide or
Person's lithium carbonate form exists, and lithium hydroxide powder, which is exposed in air, can be absorbed carbon dioxide conversion into lithium carbonate.Work as residual
Lithium is brought into lithium ion battery, can be with electrolyte generated reactive gas in the formation of Li-ion batteries stage, while unreacted is complete
Lithium carbonate and also will continue to produce gas with the electrolysis remaining substance of qualitative response or weaken the performance of lithium ion battery, therefore just
It needs to avoid as far as possible in the material synthesis processes of pole.Therefore the above results show to save precursor preparation technique, using raw material chemical combination
Object directly synthesizes cobalt nickel system positive electrode feasible process, and the synthetic reaction is relatively sufficiently thoroughly.
3, full battery preparation and Performance Evaluation
The positive electrode powder that embodiment and comparative example is prepared is as a positive electrode active material by 21700 cylindrical batteries
It is 4.8-5.2Ah or so power battery that design, which is prepared into capacity, using cylindrical battery appearance nargin having the same as standard when design
(the effective volume percentage of always closing for the volume and cylindrical battery that i.e. active principle accounts in cylindrical battery, usually 96% is left
It is right).Production full battery is mainly used for investigating lithium battery circulation and security impact.Assess applicable kind wherein as winding knot
The cell diameter of 21700 fashioned iron housing battery of structure, production is 21mm, is highly 71mm.
The volume of above-mentioned 21700 single battery is fixed simultaneously, such as can be improved the compacted density of positive/negative pole piece,
Under the conditions of certain design plot ratio, the active material of positive/negative plate can be some more, lithium battery energy meeting apparent in this way
It improves, bring direct effect is to improve the energy density of lithium battery.The design of usual lithium battery is the compacting based on pole piece
Density design.
Anode pole piece preparation is usually by preparing slurry, coating and cold pressing, and the techniques such as cutting are made, and effectively anode is living in pole piece
Property content of material be 97.5%, pole coating average weight be 0.0260g/cm3, pole coating width is 62mm, pole piece activity
The substance gross area is 937.4cm2, with a thickness of 13 μm, the positive electrode powder of embodiment and comparative example is prepared Al foil substrate
Pole piece compaction density it is as shown in table 7 below.As shown in Table 7, Elements Atom is than identical positive electrode through changing its particulate matter
After suitable draw ratio, the pole piece compaction density of material preparation has biggish promotion (3%-13.5%), to the pressure of NCA material
Real density promotion is especially apparent (13.2%), and reason may is that the cause for being prepared into the material of certain draw ratio its structure itself
Close property improves, and when being prepared into pole piece, the orientation of its material is obvious, and it is close to help to improve pole piece compacting in this way
Degree, on the basis of ensuring material electrochemical performance, can effectively promote the unit volume or Unit Weight energy of lithium battery
Density.
7 embodiment pole piece compaction density of table
Embodiment |
Pole piece compaction density (g/cm3) |
Embodiment 1 |
4.25 |
Embodiment 2 |
3.9 |
Embodiment 3 |
3.6 |
Embodiment 4 |
4.1 |
Embodiment 5 |
4.05 |
Comparative example 1 |
3.95 |
Comparative example 2 |
3.61 |
Comparative example 3 |
3.18 |
Comparative example 4 |
3.71 |
Comparative example 5 |
3.58 |
The preparation method of negative electrode tab usually via slurry is prepared, is coated with, cold pressing, the processes preparation such as cutting.Using artificial stone
When ink is used as negative electrode active material, pole piece effective negative electrode active material (artificial graphite) content after preparation is 96.0%, pole piece
Coating weight is 0.0164g/cm2, pole coating width is 63.5mm, and the pole piece active material gross area is 1009.65cm2, copper foil
Base material thickness is 9 μm, and pole piece compaction density is calculated as 1.65g/cm with active material3。
To be welded with the positive plate of aluminium pole ears, isolation film (without nano aluminium oxide processing with a thickness of 16 μm of PP/PE/
PP composite isolated film), it is welded with negative electrode tab of nickel tab etc. and winds in order and be prepared into the naked battery core of cylinder, and tab is put on absolutely
Enter shell after edge ring, using laser welding by nickel tab welding in cylinder bottom, be then prepared into the reeded naked battery core of tool through curling,
Fluid injection is cooled down after drying, and tab is successively being welded to the protection component such as CID, PTC and Vent, is encapsulated after standing in LIP-
10AHB06 type high temperature is melted into machine chemical conversion (formation voltage 0~4.2V, 0.1C charging, 0.2C electric discharge, temperature 45 C ± 2 DEG C), carries out
Volume test (test voltage 3.0~4.2V, 0.2C, 0.5C) selects up-to-standard battery core for subsequent Performance Evaluation.
Lithium battery prepared by the positive electrode of embodiment 4, embodiment 5, comparative example 4, comparative example 5 is put into 60 DEG C of baking ovens
In, electrode, which is linked into, carries out 1C/1C on LIP-10AHB06 type high temperature chemical conversion machine, and 3.0-4.2V cycle detection obtains Fig. 2's
High temperature circulation is as a result, curve 2-a, 2-b, 2-c and 2-d are respectively corresponding embodiment 4, embodiment 5, comparative example 4, comparative example 5 just
The lithium battery of pole material preparation.From Figure 2 it can be seen that the lithium ion battery of the positive electrode of the embodiment of the present invention 4 and embodiment 5 preparation
Cycle performance is excellent, is still greater than 90% through 300 weeks circulation volume conservation rates, the positive electrode preparation of comparative example 4 and comparative example 5
Although lithium ion battery early period circulation it is more steady, 250 weeks or so be start to dive, the internal resistance of corresponding lithium-ion electric core
Start to become larger, show that lithium battery interior has occurred unknown side reaction and leads to capacity rapid decay, it is still necessary to will be into for related reason
One step dissection and analysis.
4, button cell preparation and Performance Evaluation
It weighs 70gN- methyl pyrrole and omits alkanone (NMP) in experiment dispersion machine container, stirring is opened, the case where stirring
Lower 5g Kynoar (PVDF Solef6020) powder that metering is added, weighs 5g conductive carbon again after waiting adhesives to be completely dissolved
Powder (SP) is added in above-mentioned solution, and after high speed dispersion 60min, final comminuting matter 90g prepared by Example 4 is added to
It states in solution, reduction mixing speed discharging is spare after dispersing 1~1.5h.
It takes with a thickness of 16 μm of aluminium foils as collector, the slurry of above-mentioned preparation is spread evenly across on aluminium foil and in drying box
Middle drying, baking temperature are 105 DEG C, and positive plate is prepared in baking time 1h.
The positive plate of preparation is compacted, pole piece active material compacted density is 3.3g/cm3, and active matter thickness is about 85 μm,
Overall thickness is about 100 μm.Positive plate preparation 2032 type button cell of CR after taking above-mentioned compacting simultaneously, is lithium metal to electrode
Piece (is produced from Tianjin, 99.9%), electrolyte LBC301 stand 6~10h examination with computer after detaining electricity production.At normal temperature, with 2000
Type battery test system (Wuhan production) carries out volume test to battery, and charge and discharge process is 3.0~4.35V, and charge-discharge magnification is
0.1C, corresponding current density are 1mA/cm2, obtain the result of Fig. 4.
As shown in Figure 4, the positive electrode specific capacity that prepared by embodiment 4 is 169, and there are 3.88V and 3.56V two for discharge curve
A discharge platform, discharge curve is gentle, and coulombic efficiency is greater than 98%, and corresponding charging curve equally exists 2 platforms, shows to make
Standby material structure is complete, good reversibility.
5, safe drift bolt test
It prepared by the above-mentioned positive electrode using embodiment 1, embodiment 4, embodiment 5, comparative example 4 and comparative example 5
21700 type cylinder type lithium ion secondary batteries are followed closely by QC/T 743-2006 (electric road vehicle lithium-ions battery)
Thorn (nail diameter of phi 8mm, puncture speed are 20~25mm/s), overcharges (constant-current charge to 200% rated capacity) test, will test
Qualified every group of lithium battery electric core takes 2-3 only, the constant temperature 2h under room temperature condition (23 DEG C ± 2 DEG C), then in LIP-10AHB06 type
It is discharged to 3.0V by 0.5C on high temperature chemical conversion machine, discharge off stands 30s, the indexs such as battery core detection battery core thickness, internal resistance are taken out,
Restocking by 0.5C charges to 4.2V again again, then with 20mA low current CV to blanking voltage is 4.2V, retrieves battery measurement
Thickness holds voltage and internal resistance, and battery core is then stood 2 hours and is tested by standard, is obtained such as Fig. 3-a (comparative example 5), Fig. 3-
Representative result shown in b (embodiment 5) and table 8.
8 embodiment sting test result of table
By Fig. 3-a and Fig. 3-b as it can be seen that the lithium battery sting abuse condition prepared using the embodiment of the present invention 5 and comparative example 5
It can pass through down, heat up unobvious, but the temperature rising in test of the lithium battery of the preparation of comparative example 5 is high compared with embodiment 5, and electricity
Pressure directly fall to zero, show may be during the test certain protection structures in action.Simultaneously by table 7 as it can be seen that comparison
It increased dramatically after the inner walkway of 5 battery core of example, actually lost the use condition as reversible lithium ion battery.So
This drift bolt test can by be mainly cylindrical battery component in action, comparative example 5 prepare material in use process
In there are biggish security risks.
A specific embodiment of the invention is described above by embodiment, it will be understood by those skilled in the art that on
Literary embodiment is merely for the purpose of citing, it is not considered that limiting the protection scope of the present invention with this, those skilled in the art are not
It can be modified, change or replacement under the premise of disengaging spirit of that invention, still, according to various etc. made by the present invention
With variation, the range that the present invention is covered is still fallen within.