Summary of the invention
Technical problem to be solved by this invention is for above-mentioned prior art present situation, and provide cation mixing degree low, a kind of rich lithium nickel cobalt alumina positive electrode that electrical property and cycle life are outstanding, and provide that technique is simple, easy to operate, automaticity is high, pollute the preparation method of little a kind of rich lithium nickel cobalt alumina positive electrode.
The present invention solves the problems of the technologies described above adopted technical scheme:
A rich lithium nickel cobalt alumina positive electrode, wherein: the general formula of rich lithium nickel cobalt alumina positive electrode is Li
1+nni
0.7+xco
0.3-x-y-zal
ym
zo
20 < x < 0.3 wherein, 0.01 < y < 0.1,0≤z < 0.03, x+y+z < 0.3,0 < n < 0.25, M element is one or more in cobalt, manganese, magnesium, titanium, zirconium, fluorine, boron, aluminium.
The technical measures of optimizing also comprise:
It is spherical that the molecular structure of above-mentioned rich lithium nickel cobalt alumina positive electrode is class, and the longitudinal radius of molecular structure and the lateral radius ratio of rich lithium nickel cobalt alumina positive electrode are 0.5 to 2.0.
A preparation method for rich lithium nickel cobalt alumina positive electrode, comprises the following steps:
Step 1: nickel cobalt aluminium presoma is carried out to pre-oxidation calcination processing, and pre-oxidation calcination processing temperature is 300 ℃ to 800 ℃, and the pre-oxidation calcination processing time is 5h to 25h, and cooling with stove after pre-oxidation calcination processing, fragmentation is sieved;
Step 2: be to carry out sintering after 1:1.02 to 1:1.25 mixes according to the mol ratio of metal cation and lithium ion by the mixture after sieving in step 1 and lithium salt solution, sintering temperature is 650 ℃ to 950 ℃, sintering sintering 5h to 25h, during sintering, in stove, continue to pass into oxygen or air, cooling with stove after sintering, fragmentation is sieved, and obtains rich lithium nickel cobalt alumina positive electrode intermediate product;
Step 3: the intermediate product obtaining in step 2 is added in high-speed mixer and mixed with detergent solution, and incorporation time is 0.1h to 2h, after mixing carries out solidliquid mixture suction filtration and dries, and sieves;
Step 4: the mixed product that sieves in step 3 is carried out to sintering processes, and sintering temperature is 200 ℃ to 800 ℃, and sintering time is 5h to 30h, cooling with stove after sintering, obtains rich lithium nickel cobalt alumina positive electrode after sieving.
Before above-mentioned step 1, be also provided with nickel cobalt aluminium presoma preparation process: nickel salt solution, cobalt salt solution and aluminum salt solution are mixed, concentration of metal ions after mixing in solution is 0.5mol/l to 2.0mol/l, again solution stream after enveloping agent solution, precipitant solution and mixing are added in reactor, add thermal agitation and carry out precipitation reaction, the slurry starting overflowing after fully reacting carries out Separation of Solid and Liquid, solid product after separation, after washing, drying, obtains spherical nickel cobalt aluminium presoma.
Above-mentioned detergent solution is the mixed liquor of deionized water or ethanol or deionized water and ethanol.
Above-mentioned precipitant solution is NaOH precipitant solution.
In above-mentioned step 3 mixed process, add covering; At least one in covering containing element cobalt, manganese, magnesium, titanium, zirconium, fluorine, boron, aluminium.
Above-mentioned nickel salt solution is at least one in nickel sulfate solution, nickel chloride solution, and cobalt salt solution is at least one in cobalt sulfate solution, cobalt chloride solution, and aluminum salt solution is at least one in aluminum sulfate solution, liquor alumini chloridi.
In above-mentioned step 1, nickel ion, cobalt ions, aluminum ions mol ratio are 0.75 ~ 0.85:0.1 ~ 0.2:0.03 ~ 0.07.
Lithium salts in above-mentioned step 3 is at least one in lithium carbonate, lithium hydroxide, lithium acetate, lithium oxalate.
Compared with prior art, the invention has the advantages that:
Nickel cobalt aluminium presoma is mixed with excessive lithium source, then at high temperature carry out sintering, again by the coated means of washing, remove the residual lithium of particle surface, reduce impurity lithium content and the pH value of finished product, thereby obtain perfect structure, physicochemical property and electrical property be good rich lithium nickel cobalt alumina positive electrode all.The rich lithium nickel cobalt alumina positive electrode synthesizing by this method, cation mixing degree is low, and electrical property and cycle life are outstanding; On the other hand, reduce the dependence of NCA material sintering process to oxygen in the past, can in air atmosphere, carry out sintering and synthesize, reduced production difficulty.Rich lithium nickel cobalt alumina positive electrode stability and the consistency by preparation method of the present invention, prepared are better, can realize automaticity high, and simple to operate, environmental pollution is few, is conducive to suitability for industrialized production; Adopt in addition in positive electrode prepared by the present invention that nickel content is high and cobalt content is low, greatly reduced the cost of raw material.
The rich lithium nickel of the lithium ion battery cobalt alumina positive electrode that utilizes the present invention to prepare, it is spherical that crystal size is evenly distributed, crystal morphology is class, has good bulk density; Its specific capacity can reach 180mAh/g ~ 200 mAh/g, and 1C discharges and recharges 300 weeks circulation volume conservation rates and is greater than 90%, and tap density is 2.3 ~ 2.9g/cm
3, average grain diameter is 5 ~ 20um, and it is low that impurity lithium content is less than 0.2%, 85 ℃ of high temperature flatulence rate, and the reversible capacity between 3.0V ~ 4.3V is greater than 180Ah/g; Utilize the rich lithium nickel of lithium ion battery cobalt alumina positive electrode prepared by the present invention to there is very high capacity and good cycle performance, have good anti-high temperature flatulence performance simultaneously.
Embodiment
Below in conjunction with accompanying drawing, the embodiment of the present invention is described in further detail.
A rich lithium nickel cobalt alumina positive electrode, the general formula of rich lithium nickel cobalt alumina positive electrode is Li
1+nni
0.7+xco
0.3-x-y-zal
ym
zo
20 < x < 0.3 wherein, 0.01 < y < 0.1,0≤z < 0.03, x+y+z < 0.3,0 < n < 0.25, M element is one or more in cobalt, manganese, magnesium, titanium, zirconium, fluorine, boron, aluminium; It is spherical that the molecular structure of rich lithium nickel cobalt alumina positive electrode is class, 0.5 < a/b < 2.0 in its SEM collection of illustrative plates, longitudinal radius that wherein a is material molecule, the lateral radius that b is material molecule.
A preparation method for rich lithium nickel cobalt alumina positive electrode, comprises the following steps:
Step 1: the preparation of nickel cobalt aluminium presoma: nickel salt solution, cobalt salt solution and aluminum salt solution are mixed, concentration of metal ions after mixing in solution is 0.5mol/l to 2.0mol/l, again solution stream after enveloping agent solution, precipitant solution and described mixing are added in reactor, add thermal agitation and carry out precipitation reaction, the slurry starting overflowing after fully reacting carries out Separation of Solid and Liquid, solid product after separation, after washing, drying, obtains spherical nickel cobalt aluminium presoma; The nickel cobalt aluminium presoma occurring in claim 3 refers to the nickel cobalt aluminium compound of using for the preparation of lithium battery.Precipitant solution is NaOH precipitant solution; Enveloping agent solution is can be with
metalion forms the compound solution of complex ion, can be cyanide, hydroxide, citrate, pyrophosphate, thiosulfate, sulphite etc.
Step 2: the nickel cobalt aluminium presoma obtaining in step 1 is carried out to pre-oxidation calcination processing, and pre-oxidation calcination processing temperature is 300 ℃ to 800 ℃, and the pre-oxidation calcination processing time is 5h to 25h, and cooling with stove after pre-oxidation calcination processing, fragmentation is sieved;
Step 3: be to carry out sintering after 1:1.02 to 1:1.25 mixes according to the mol ratio of metal cation and lithium ion by the mixture after sieving in step 2 and lithium salt solution, sintering temperature is 650 ℃ to 950 ℃, sintering sintering 5h to 25h, during sintering, in stove, continue to pass into oxygen or air, cooling with stove after sintering, fragmentation is sieved, and obtains rich lithium nickel cobalt alumina positive electrode intermediate product;
Step 4: the intermediate product obtaining in step 3 is added in high-speed mixer and mixed with detergent solution, and incorporation time is 0.1h to 2h, after mixing carries out solidliquid mixture suction filtration and dries, and sieves; Detergent solution is the mixed liquor of deionized water or ethanol or deionized water and ethanol;
Step 5: the mixed product that sieves in step 4 is carried out to sintering processes, and sintering temperature is 200 ℃ to 800 ℃, and sintering time is 5h to 30h, cooling with stove after sintering, obtains rich lithium nickel cobalt alumina positive electrode after sieving.
In described step 4 mixed process, add covering; At least one in covering containing element cobalt, manganese, magnesium, titanium, zirconium, fluorine, boron, aluminium.
In described step 1, nickel salt is at least one in nickelous sulfate, nickel chloride, and cobalt salt is at least one in cobaltous sulfate, cobalt chloride, and aluminium salt is at least one in aluminum sulfate, aluminium chloride.
In described step 1, nickel ion, cobalt ions, aluminum ions mol ratio are 0.75 ~ 0.85:0.1 ~ 0.2:0.03 ~ 0.07.
Lithium salts in described step 3 is at least one in lithium carbonate, lithium hydroxide, lithium acetate, lithium oxalate.
Below in conjunction with experiment, be described further:
Embodiment mono-:
Step 1: the preparation of nickel cobalt aluminium presoma: the nickel sulfate solution that is 0.75:0.20:0.05 by the mol ratio of Ni:Co:Al, cobalt sulfate solution, aluminum sulfate solution are that raw material mixes, concentration of metal ions after mixing in solution is 1.0M, again by enveloping agent solution, precipitant solution together with solution after described mixing and stream add in the reactor that end liquid is housed, add thermal agitation and carry out precipitation reaction, the slurry starting overflowing after fully reacting carries out Separation of Solid and Liquid, solid product after separation, after washing, drying, obtains spherical nickel cobalt aluminium presoma;
Step 2: the nickel cobalt aluminium presoma just obtaining in step 1 carries out pre-oxidation calcination processing, and pre-oxidation calcination processing temperature is 650 ℃, and the pre-oxidation calcination processing time is 12h, and cooling with stove after pre-oxidation calcination processing, fragmentation is sieved;
Step 3: be to carry out sintering after 1:1.1 mixes according to the mol ratio of metal cation and lithium ion by the mixture after sieving in step 2 and lithium carbonate, sintering temperature is 900 ℃, sintering sintering 20h, during sintering, in stove, continue to pass into air, cooling with stove after sintering, fragmentation is sieved, and obtains nickel cobalt alumina positive electrode intermediate product;
Step 4: the intermediate product obtaining in step 3 is added in high-speed mixer and mixed with detergent solution, add covering simultaneously; Incorporation time is 1h, after mixing, solidliquid mixture is carried out to suction filtration and dries, and sieves; In the covering of the present embodiment, comprise cobalt element.
Step 5: the mixed product that sieves in step 4 is carried out to sintering processes, and sintering temperature is 600 ℃, and sintering time is 10h, cooling with stove after sintering, obtains nickel cobalt alumina positive electrode after sieving.
The tap density 2.46g/cm of the nickel cobalt alumina positive electrode of preparing in the present embodiment after testing,
3, impurity lithium content is 0.06%, and this positive electrode processing characteristics is good, and while being made into battery, capacity is 186mAh/g, and it is 95.7% that 1C discharges and recharges 300 weeks capability retentions, and battery performance is good, and without disadvantageous changes such as bulging, 85 ℃ of thickness conservation rates are 106.2%.
Embodiment bis-:
Step 1: the preparation of nickel cobalt aluminium presoma: the nickel sulfate solution that is 0.77:0.18:0.05 by the mol ratio of Ni:Co:Al, cobalt sulfate solution, aluminum sulfate solution are that raw material mixes, concentration of metal ions after mixing in solution is 1.0M, again by enveloping agent solution, precipitant solution together with solution after described mixing and stream add in the reactor that end liquid is housed, add thermal agitation and carry out precipitation reaction, the slurry starting overflowing after fully reacting carries out Separation of Solid and Liquid, solid product after separation, after washing, drying, obtains spherical nickel cobalt aluminium presoma;
Step 2: the nickel cobalt aluminium presoma just obtaining in step 1 carries out pre-oxidation calcination processing, and pre-oxidation calcination processing temperature is 500 ℃, and the pre-oxidation calcination processing time is 12h, and cooling with stove after pre-oxidation calcination processing, fragmentation is sieved;
Step 3: be to carry out sintering after 1:1.12 mixes according to the mol ratio of metal cation and lithium ion by the mixture after sieving in step 2 and lithium hydroxide, sintering temperature is 850 ℃, sintering sintering 18h, during sintering, in stove, continue to pass into air, cooling with stove after sintering, fragmentation is sieved, and obtains nickel cobalt alumina positive electrode intermediate product;
Step 4: the intermediate product obtaining in step 3 is added in high-speed mixer and mixed with detergent solution, and incorporation time is 1.5h, after mixing carries out solidliquid mixture suction filtration and dries, and sieves;
Step 5: the mixed product that sieves in step 4 is carried out to sintering processes, and sintering temperature is 700 ℃, and sintering time is 12h, cooling with stove after sintering, obtains nickel cobalt alumina positive electrode after sieving.
After testing, the tap density 2.43g/cm3 of the rich lithium nickel cobalt alumina positive electrode of preparing in the present embodiment, impurity lithium content is 0.05%, this positive electrode processing characteristics is good, and while being made into battery, capacity is 189mAh/g, it is 95.5% that 1C discharges and recharges 300 weeks circulation conservation rates, battery performance is good, and without disadvantageous changes such as bulging, 85 ℃ of thickness conservation rates are 107.1%.
Embodiment tri-:
Step 1: the preparation of nickel cobalt aluminium presoma: the nickel chloride solution that is 0.8:0.15:0.05 by the mol ratio of Ni:Co:Al, cobalt chloride solution, liquor alumini chloridi are that raw material mixes, concentration of metal ions after mixing in solution is 1.5M, again by enveloping agent solution, precipitant solution together with solution after described mixing and stream add in the reactor that end liquid is housed, add thermal agitation and carry out precipitation reaction, the slurry starting overflowing after fully reacting carries out Separation of Solid and Liquid, solid product after separation, after washing, drying, obtains spherical nickel cobalt aluminium presoma;
Step 2: the nickel cobalt aluminium presoma just obtaining in step 1 carries out pre-oxidation calcination processing, and pre-oxidation calcination processing temperature is 450 ℃, and the pre-oxidation calcination processing time is 12h, and cooling with stove after pre-oxidation calcination processing, fragmentation is sieved;
Step 3: be to carry out sintering after 1:1.15 mixes according to the mol ratio of metal cation and lithium ion by the mixture after sieving in step 2 and lithium acetate, sintering temperature is 830 ℃, sintering sintering 15h, during sintering, in stove, continue to pass into oxygen, cooling with stove after sintering, fragmentation is sieved, and obtains nickel cobalt alumina positive electrode intermediate product;
Step 4: the intermediate product obtaining in step 3 is added in high-speed mixer and mixed with detergent solution, add covering simultaneously; Incorporation time is 2h, after mixing, solidliquid mixture is carried out to suction filtration and dries, and sieves; In the covering of the present embodiment, comprise manganese, magnesium elements.
Step 5: the mixed product that sieves in step 4 is carried out to sintering processes, and sintering temperature is 550 ℃, and sintering time is 12h, cooling with stove after sintering, obtains nickel cobalt alumina positive electrode after sieving.
After testing, the tap density 2.49g/cm3 of the rich lithium nickel cobalt alumina positive electrode of preparing in the present embodiment, impurity lithium content is 0.07%, this positive electrode processing characteristics is good, and while being made into battery, capacity is 192mAh/g, it is 95.2% that 1C discharges and recharges 300 weeks circulation conservation rates, battery performance is good, and without disadvantageous changes such as bulging, 85 ℃ of thickness conservation rates are 108.7%.
Embodiment tetra-:
Step 1: the preparation of nickel cobalt aluminium presoma: the nickel chloride solution that is 0.83:0.1:0.07 by the mol ratio of Ni:Co:Al, cobalt chloride solution, liquor alumini chloridi are that raw material mixes, concentration of metal ions after mixing in solution is 1.5M, again by enveloping agent solution, precipitant solution together with solution after described mixing and stream add in the reactor that end liquid is housed, add thermal agitation and carry out precipitation reaction, the slurry starting overflowing after fully reacting carries out Separation of Solid and Liquid, solid product after separation, after washing, drying, obtains spherical nickel cobalt aluminium presoma;
Step 2: the nickel cobalt aluminium presoma just obtaining in step 1 carries out pre-oxidation calcination processing, and pre-oxidation calcination processing temperature is 480 ℃, and the pre-oxidation calcination processing time is 12h, and cooling with stove after pre-oxidation calcination processing, fragmentation is sieved;
Step 3: be to carry out sintering after 1:1.1 mixes according to the mol ratio of metal cation and lithium ion by the mixture after sieving in step 2 and lithium oxalate, sintering temperature is 800 ℃, sintering sintering 12h, during sintering, in stove, continue to pass into air, cooling with stove after sintering, fragmentation is sieved, and obtains nickel cobalt alumina positive electrode intermediate product;
Step 4: the intermediate product obtaining in step 3 is added in high-speed mixer and mixed with detergent solution, add covering simultaneously; Incorporation time is 2h, after mixing, solidliquid mixture is carried out to suction filtration and dries, and sieves; In the covering of the present embodiment, comprise titanium, zr element.
Step 5: the mixed product that sieves in step 4 is carried out to sintering processes, and sintering temperature is 450 ℃, and sintering time is 12h, cooling with stove after sintering, obtains nickel cobalt alumina positive electrode after sieving.
After testing, the tap density 2.48g/cm3 of the rich lithium nickel cobalt alumina positive electrode of preparing in the present embodiment, impurity lithium content is 0.06%, this positive electrode processing characteristics is good, and while being made into battery, capacity is 190mAh/g, it is 96.2% that 1C discharges and recharges 300 weeks circulation conservation rates, battery performance is good, and without disadvantageous changes such as bulging, 85 ℃ of thickness conservation rates are 107.5%.
Embodiment five:
Step 1: the preparation of nickel cobalt aluminium presoma: the nickel chloride solution that is 0.85:0.12:0.03 by the mol ratio of Ni:Co:Al, cobalt chloride solution, liquor alumini chloridi are that raw material mixes, concentration of metal ions after mixing in solution is 1.5M, again by enveloping agent solution, precipitant solution together with solution after described mixing and stream add in the reactor that end liquid is housed, add thermal agitation and carry out precipitation reaction, the slurry starting overflowing after fully reacting carries out Separation of Solid and Liquid, solid product after separation, after washing, drying, obtains spherical nickel cobalt aluminium presoma;
Step 2: the nickel cobalt aluminium presoma just obtaining in step 1 carries out pre-oxidation calcination processing, and pre-oxidation calcination processing temperature is 600 ℃, and the pre-oxidation calcination processing time is 10h, and cooling with stove after pre-oxidation calcination processing, fragmentation is sieved;
Step 3: be to carry out sintering after 1:1.09 mixes according to the mol ratio of metal cation and lithium ion by the mixture after sieving in step 2 and lithium carbonate, sintering temperature is 770 ℃, sintering sintering 10h, during sintering, in stove, continue to pass into air, cooling with stove after sintering, fragmentation is sieved, and obtains nickel cobalt alumina positive electrode intermediate product;
Step 4: the intermediate product obtaining in step 3 is added in high-speed mixer and mixed with detergent solution, add covering simultaneously; Incorporation time is 2h, after mixing, solidliquid mixture is carried out to suction filtration and dries, and sieves; In the covering of the present embodiment, comprise fluorine, boron, aluminium element.
Step 5: the mixed product that sieves in step 4 is carried out to sintering processes, and sintering temperature is 550 ℃, and sintering time is 12h, cooling with stove after sintering, obtains nickel cobalt alumina positive electrode after sieving.
After testing, the tap density 2.45g/cm3 of the rich lithium nickel cobalt alumina positive electrode of preparing in the present embodiment, impurity lithium content is 0.08%, this positive electrode processing characteristics is good, and while being made into battery, capacity is 194mAh/g, it is 95.1% that 1C discharges and recharges 300 weeks circulation conservation rates, battery performance is good, and without disadvantageous changes such as bulging, 85 ℃ of thickness conservation rates are 109.1%.
Compare with existing preparation method:
Step 1: the preparation of nickel cobalt aluminium presoma: be that raw material mixes by Ni:Co:Al mol ratio 0.75:0.20:0.05 nickel sulfate solution, cobalt sulfate solution, aluminum sulfate solution, concentration of metal ions after mixing in solution is 1.0 mol/L, again by enveloping agent solution, precipitant solution together with solution after described mixing and stream add in the reactor that end liquid is housed, add thermal agitation and carry out precipitation reaction, the slurry starting overflowing after fully reacting carries out Separation of Solid and Liquid, solid product after separation, after washing, drying, obtains spherical nickel cobalt aluminium presoma;
Step 2: the nickel cobalt aluminium presoma obtaining in step 1 is carried out to pre-oxidation calcination processing, and sintering temperature is 650 ℃, sintering 12h, cooling with stove after sintering, fragmentation is sieved;
Step 3: the mixture after sieving in step 2 and lithium salts are mixed to laggard row according to metal sun and Li ion mol ratio 1:1.02 and carry out high-temperature calcination, sintering temperature is 900 ℃, sintering 20h, continue during this time to pass into oxygen, cooling with stove after sintering, fragmentation obtains lithium nickel cobalt alumina positive electrode after sieving.
After testing, the tap density 2.43g/cm3 of lithium nickel cobalt alumina positive electrode prepared by this method, impurity lithium content is 0.35%, this positive electrode processing characteristics is poor, easily produces jelly phenomenon, while being made into battery, capacity is 178mAh/g, it is 84.3% that 1C discharges and recharges 300 weeks circulation conservation rates, and battery bulging phenomenon is serious, 85 ℃ high temperature thickness conservation rates 134.3%.
Embodiment data and comparative example data are compared as follows:
Numbering |
Impurity lithium content |
Capacity mAh/g |
300 weeks circulation volume conservation rates |
The high temperature thickness conservation rate of 85 ℃/4h |
Comparative example |
0.35% |
178 |
84.3% |
134.3% |
Embodiment mono- |
0.05% |
186 |
95.7% |
106.2% |
Embodiment bis- |
0.05% |
189 |
95.5% |
107.1% |
Embodiment tri- |
0.07% |
192 |
95.0% |
108.0% |
Embodiment tetra- |
0.06% |
190 |
96.2% |
107.5% |
Embodiment five |
0.08% |
194 |
95.1% |
109.1% |
In above-described embodiment, while choosing the two-end-point of corresponding span during value, little on experimental result impact.
In above-described embodiment, nickel salt, cobalt salt, aluminium salt are chosen the mixture of sulfate, hydrochloride or sulfate and hydrochloride, all do not affect experimental result.
Most preferred embodiment of the present invention is illustrated, and the various variations of being made by those of ordinary skills or remodeling can not depart from the scope of the present invention.