Embodiment
The lithium ion cell positive that the invention provides comprises conducting base and coating and/or is filled in positive electrode on the conducting base, and described positive electrode comprises positive active material, conductive agent and adhesive, and described positive active material is LiNi
xCo
yMn
1-x-yO
2, 0.1≤x≤0.5,0.1≤y≤0.5, wherein, described conductive agent contains sheet conductive agent and spherical conductive agent.
The specific area of described sheet conductive agent is a 10-50 rice
2/ gram is preferably 20-45 rice
2/ gram.The kind of sheet conductive agent comprises graphite, is preferably native graphite.Described native graphite specific area is a 10-50 rice
2/ gram is preferably 20-45 rice
2/ gram.Wherein, in the present invention, specific area adopts cryogenic nitrogen absorption BET method to measure.Weight with described positive active material is benchmark, and the content of described sheet conductive agent is 0.2-5 weight %, is preferably 0.5-3 weight %.
The specific area of described spherical conductive agent is a 80-850 rice
2/ gram is preferably 100-800 rice
2/ gram.The kind of spherical conductive agent comprises acetylene black and carbon black.The specific area of described acetylene black is a 80-350 rice
2/ gram is preferably 100-300 rice
2/ gram.The specific area of described carbon black is a 400-850 rice
2/ gram is preferably 450-800 rice
2/ gram.Weight with described positive active material is benchmark, and the content of described spherical conductive agent is 0.2-5.5 weight %, is preferably 0.5-5 weight %.
According to lithium ion cell positive provided by the invention, described positive active material is LiNi
xCo
yMn
1-x-yO
2, 0.1≤x≤0.5,0.1≤y≤0.5 wherein.This positive active material has been conventionally known to one of skill in the art, can be commercially available, also can be by existing method preparation, for example disclosed method among the CN1614801A.
The kind of described adhesive and content are conventionally known to one of skill in the art, for example one or more in fluorine resin and polyolefin compound such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), the butadiene-styrene rubber (SBR).In general, according to the difference of adhesive therefor kind, be benchmark with the weight of positive active material, the content of adhesive is 0.01-8 weight %, is preferably 0.02-5 weight %.
The kind of described anodal conducting base has been conventionally known to one of skill in the art, for example can be selected from aluminium foil, Punching steel strip.In the specific embodiment of the present invention, use aluminium foil as anodal conducting base.
The preparation method of described positive pole can adopt conventional preparation method.For example, with described positive electrode and solvent, apply and/or be filled on the described conducting base, drying is rolled or is not rolled, and can obtain described positive pole.Under the preferable case, earlier spherical conductive agent and sheet conductive agent are mixed, then conductive agent, positive active material, adhesive and the solvent that mixes evenly formed slurry, this slurry is applied and/or is filled on the conducting base, drying is rolled or is not rolled.Wherein, described solvent can be selected from one or more in N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), diethylformamide (DEF), dimethyl sulfoxide (DMSO) (DMSO), the oxolane (THF); The consumption of solvent can make described pastel have viscosity and flowability, can be coated on the described conducting base to get final product.In general the weight with positive active material is benchmark, and the content 30-90 weight % of described solvent is preferably 35-85 weight %.Wherein, drying, the method for calendering and condition are conventionally known to one of skill in the art.
Lithium ion battery provided by the present invention comprises electrode group and nonaqueous electrolytic solution, and described electrode group and nonaqueous electrolytic solution are sealed in the battery container, and described electrode group comprises positive pole, negative pole and barrier film.Except using, can use conventional negative pole, barrier film, nonaqueous electrolytic solution by the positive pole provided by the invention.
Because the positive active material of lithium ion battery provided by the invention is LiNi
xCo
yMn
1-x-yO
2, the charging voltage of wherein 0.1≤x≤0.5,0.1≤y≤0.5, so lithium ion battery provided by the invention is more than or equal to 4.4 volts.
Described barrier film is arranged between positive pole and the negative pole, has electrical insulation capability and liquid retainability energy.Described barrier film can be selected from various barrier films used in the lithium ion battery, as polyolefin micro porous polyolefin membrane, polyethylene felt, glass mat or ultra-fine fibre glass paper.The position of described barrier film, character and kind are conventionally known to one of skill in the art.
Consisting of of described negative pole is conventionally known to one of skill in the art.In general, negative pole comprises conducting base and coating and/or is filled in negative material on the conducting base that described negative material comprises negative electrode active material and negative pole adhesive.
Described negative electrode active material is not particularly limited, can use embedding of this area routine to disengage the negative electrode active material of lithium, such as in native graphite, Delanium, petroleum coke, organic cracking carbon, carbonaceous mesophase spherules, carbon fiber, ashbury metal, the silicon alloy one or more, preferred natural graphite.
The kind of described negative pole adhesive and content are conventionally known to one of skill in the art, for example one or more in fluorine resin and polyolefin compound such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), the butadiene-styrene rubber (SBR); In general, according to the difference of adhesive therefor kind, be benchmark with the weight of negative electrode active material, the content of negative pole adhesive is 0.01-8 weight %, is preferably 0.02-5 weight %.
Described negative material can also comprise conductive agent, and described conductive agent is not particularly limited, and can be the cathode conductive agent of this area routine, such as in carbon black, nickel powder, the copper powder one or more.Weight with negative electrode active material is benchmark, and the content of described conductive agent is 0-15 weight %, is preferably 2-10 weight %.
The negative pole conducting base can be for negative pole conducting base conventional in the lithium ion battery, as stamped metal, and metal forming, net metal, foamed metal uses Copper Foil as the negative pole conducting base in specific embodiments of the present invention.
The preparation method of described negative pole can adopt conventional preparation method.For example, with negative material and solvent, apply and/or be filled on the described conducting base, drying is rolled or is not rolled, and can obtain described negative pole.Wherein, described solvent can be selected from one or more in N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), diethylformamide (DEF), dimethyl sulfoxide (DMSO) (DMSO), oxolane (THF) and water and the alcohols.The consumption of solvent can make described pastel have viscosity and flowability, can be coated on the described conducting base to get final product.In general, be benchmark with the weight of negative electrode active material, the content 30-90 weight % of described solvent is preferably 35-85 weight %.Wherein, drying, the method for calendering and condition are conventionally known to one of skill in the art.For example, the temperature of described drying is generally 100-150 ℃.
Described nonaqueous electrolytic solution is the mixed solution of electrolyte lithium salt and nonaqueous solvents, and it is not particularly limited, and can use the nonaqueous electrolytic solution of this area routine.Be selected from lithium hexafluoro phosphate (LiPF such as electrolyte lithium salt
6), in lithium perchlorate, LiBF4, hexafluoroarsenate lithium, lithium halide, chlorine lithium aluminate and the fluorocarbon based sulfonic acid lithium one or more.Organic solvent is selected chain acid esters and ring-type acid esters mixed solution for use, wherein the chain acid esters can be dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), carbonic acid first propyl ester (MPC), dipropyl carbonate (DPC) and other are fluorine-containing, sulfur-bearing or contain at least a in the chain organosilane ester of unsaturated bond, the ring-type acid esters can be ethylene carbonate (EC), propene carbonate (PC), vinylene carbonate (VC), gamma-butyrolacton (γ-BL), sultone and other are fluorine-containing, sulfur-bearing or contain at least a in the ring-type organosilane ester of unsaturated bond.The injection rate of electrolyte is generally 1.5-4.9g/Ah, the concentration of electrolyte be generally 0.5-2.9 rub/liter.
According to the preparation method of lithium ion battery provided by the invention, except described positive pole prepared according to method provided by the invention, other step was conventionally known to one of skill in the art.In general, described positive pole for preparing and negative pole winding are separated formation electrode group, electrode group and the electrolyte that obtains is sealed in the battery case, can obtain lithium ion battery provided by the invention by membrane layer.The method for winding of the membrane layer between positive pole and negative pole is conventionally known to one of skill in the art, does not repeat them here.
To the present invention be described in more detail by embodiment below.
Embodiment 1
This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.
(1) Zheng Ji preparation
(specific area is 150 meters with the spherical conductive agent acetylene black of 4.5 weight portions
2/ gram) and the sheet conductive agent native graphite of 0.5 weight portion (specific area is 40 meters
2/ gram) mixes.
With 100 weight portion positive active material LiNi
0.33Co
0.33Mn
0.34O
2, 4 weight portion adhesive PVDF, the above-mentioned conductive agent that mixes of 5 weight portions join in the 40 weight portion N-methyl pyrrolidones (NMP), in de-airing mixer, stir then and form uniform anode sizing agent.
This slurry is coated on wide 400 millimeters, the thick 20 microns aluminium foil equably, and 120 ℃ of oven dry, roll-ins are cut on cutting machine and obtain being of a size of 385 millimeters * 42 millimeters * 135 microns positive pole afterwards then, wherein contain 4.8 gram cathode mixtures.
(2) preparation of negative pole
100 weight portion negative electrode active material native graphites, 4 weight portion adhesive polytetrafluoroethylene (PTFE)s, 4 weight portion conductive agent carbon blacks are joined in the 40 weight portion methyl-sulfoxides (DMSO), in de-airing mixer, stir then and form cathode size stable, homogeneous.
This slurry is coated on wide 400 millimeters, the thick 10 microns Copper Foil equably, after 120 ℃ of oven dry, rolling, on cutting machine, cuts and obtain being of a size of 43 millimeters * 355 millimeters * 135 microns negative pole, wherein contain 2.7 gram negative pole compounds.
(3) assembling of battery
With LiPF
6Be configured to LiPF with ethylene carbonate (EC) and diethyl carbonate (DEC)
6Concentration is the solution (wherein, the volume ratio of EC and DEC is 1: 1) of 1.0 mol, obtains nonaqueous electrolytic solution.The negative pole that positive pole, membrane layer, (2) that (1) is obtained obtain is successively with the stacked electrode group that is wound into scroll of up-coiler, the electrode group that obtains is put into the battery case of an end opening, and inject above-mentioned nonaqueous electrolytic solution with the amount of 3.8g/Ah, make lithium ion battery A1 after the sealing.
Embodiment 2
This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.
(1) Zheng Ji preparation
(specific area is 600 meters with the spherical conductive agent carbon black of 4 weight portions
2/ gram) and the sheet conductive agent native graphite of 1 weight portion (specific area is 25 meters
2/ gram) mixes.
With 100 weight portion positive active material LiNi
0.1Co
0.1Mn
0.8O
2, 1 weight portion adhesive PVDF, the above-mentioned conductive agent that mixes of 5 weight portions join in the 70 weight portion N-methyl pyrrolidones (NMP), in de-airing mixer, stir then and form uniform anode sizing agent.
This slurry is coated on wide 400 millimeters, the thick 20 microns aluminium foil equably, and 120 ℃ of oven dry, roll-ins are cut on cutting machine and obtain being of a size of 385 millimeters * 42 millimeters * 135 microns positive pole afterwards then, wherein contain 4.8 gram cathode mixtures.
(2) preparation of negative pole
100 weight portion negative electrode active material native graphites, 2 weight portion adhesive polytetrafluoroethylene (PTFE)s, 6 weight portion conductive agent carbon blacks are joined in the 70 weight portion methyl-sulfoxides (DMSO), in de-airing mixer, stir then and form cathode size stable, homogeneous.
This slurry is coated on wide 400 millimeters, the thick 10 microns Copper Foil equably, after 120 ℃ of oven dry, rolling, on cutting machine, cuts and obtain being of a size of 43 millimeters * 355 millimeters * 135 microns negative pole, wherein contain 2.7 gram negative pole compounds.
(3) assembling of battery
With LiPF
6Be configured to LiPF with ethylene carbonate (EC) and diethyl carbonate (DEC)
6Concentration is the solution (wherein, the volume ratio of EC and DEC is 1: 1) of 1.0 mol, obtains nonaqueous electrolytic solution.The negative pole that positive pole, membrane layer, (2) that (1) is obtained obtain is successively with the stacked electrode group that is wound into scroll of up-coiler, the electrode group that obtains is put into the battery case of an end opening, and inject above-mentioned nonaqueous electrolytic solution with the amount of 3.8g/Ah, make lithium ion battery A2 after the sealing.
Embodiment 3
This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.
(1) Zheng Ji preparation
(specific area is 500 meters with the spherical conductive agent carbon black of 2 weight portions
2/ gram), (specific area is 200 meters to the spherical conductive agent acetylene black of 1 weight portion
2/ gram) and the sheet conductive agent native graphite of 1.5 weight portions (specific area is 30 meters
2/ gram) mixes.
With 100 weight portion positive active material LiNi
0.45Co
0.45Mn
0.1O
2, 3 weight portion adhesive PVDF, the above-mentioned conductive agent that mixes of 4.5 weight portions join in the 70 weight portion N-methyl pyrrolidones (NMP), in de-airing mixer, stir then and form uniform anode sizing agent.
This slurry is coated on wide 400 millimeters, the thick 20 microns aluminium foil equably, and 120 ℃ of oven dry, roll-ins are cut on cutting machine and obtain being of a size of 385 millimeters * 42 millimeters * 135 microns positive pole afterwards then, wherein contain 4.8 gram cathode mixtures.
(2) preparation of negative pole
100 weight portion negative electrode active material native graphites, 2 weight portion adhesive polytetrafluoroethylene (PTFE)s, 6 weight portion conductive agent carbon blacks are joined in the 70 weight portion methyl-sulfoxides (DMSO), in de-airing mixer, stir then and form cathode size stable, homogeneous.
This slurry is coated on wide 400 millimeters, the thick 10 microns Copper Foil equably, after 120 ℃ of oven dry, rolling, on cutting machine, cuts and obtain being of a size of 43 millimeters * 355 millimeters * 135 microns negative pole, wherein contain 2.7 gram negative pole compounds.
(3) assembling of battery
With LiPF
6Be configured to LiPF with ethylene carbonate (EC) and diethyl carbonate (DEC)
6Concentration is the solution (wherein, the volume ratio of EC and DEC is 1: 1) of 1.0 mol, obtains nonaqueous electrolytic solution.The negative pole that positive pole, membrane layer, (2) that (1) is obtained obtain is successively with the stacked electrode group that is wound into scroll of up-coiler, the electrode group that obtains is put into the battery case of an end opening, and inject above-mentioned nonaqueous electrolytic solution with the amount of 3.8g/Ah, make lithium ion battery A3 after the sealing.
Embodiment 4
This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.
(1) Zheng Ji preparation
(specific area is 700 meters with the spherical conductive agent carbon black of 2 weight portions
2/ gram) and the sheet conductive agent native graphite of 2 weight portions (specific area is 30 meters
2/ gram) mixes.
With 100 weight portion positive active material LiNi
0.2Co
0.2Mn
0.6O
2, 3 weight portion adhesive PVDF, the above-mentioned conductive agent that mixes of 4.5 weight portions join in the 70 weight portion N-methyl pyrrolidones (NMP), in de-airing mixer, stir then and form uniform anode sizing agent.
This slurry is coated on wide 400 millimeters, the thick 20 microns aluminium foil equably, and 120 ℃ of oven dry, roll-ins are cut on cutting machine and obtain being of a size of 385 millimeters * 42 millimeters * 135 microns positive pole afterwards then, wherein contain 4.8 gram cathode mixtures.
(2) preparation of negative pole
100 weight portion negative electrode active material native graphites, 2 weight portion adhesive polytetrafluoroethylene (PTFE)s, 6 weight portion conductive agent carbon blacks are joined in the 70 weight portion methyl-sulfoxides (DMSO), in de-airing mixer, stir then and form cathode size stable, homogeneous.
This slurry is coated on wide 400 millimeters, the thick 10 microns Copper Foil equably, after 120 ℃ of oven dry, rolling, on cutting machine, cuts and obtain being of a size of 43 millimeters * 355 millimeters * 135 microns negative pole, wherein contain 2.7 gram negative pole compounds.
(3) assembling of battery
With LiPF
6Be configured to LiPF with ethylene carbonate (EC) and diethyl carbonate (DEC)
6Concentration is the solution (wherein, the volume ratio of EC and DEC is 1: 1) of 1.0 mol, obtains nonaqueous electrolytic solution.The negative pole that positive pole, membrane layer, (2) that (1) is obtained obtain is successively with the stacked electrode group that is wound into scroll of up-coiler, the electrode group that obtains is put into the battery case of an end opening, and inject above-mentioned nonaqueous electrolytic solution with the amount of 3.8g/Ah, make lithium ion battery A4 after the sealing.
Embodiment 5
This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.
(1) Zheng Ji preparation
(specific area is 240 meters with the spherical conductive agent acetylene black of 1 weight portion
2/ gram) and the sheet conductive agent native graphite of 2.5 weight portions (specific area is 30 meters
2/ gram) mixes.
With 100 weight portion positive active material LiNi
0.15Co
0.35Mn
0.5O
2, 3 weight portion adhesive PVDF, the above-mentioned conductive agent that mixes of 4.5 weight portions join in the 70 weight portion N-methyl pyrrolidones (NMP), in de-airing mixer, stir then and form uniform anode sizing agent.
This slurry is coated on wide 400 millimeters, the thick 20 microns aluminium foil equably, and 120 ℃ of oven dry, roll-ins are cut on cutting machine and obtain being of a size of 385 millimeters * 42 millimeters * 135 microns positive pole afterwards then, wherein contain 4.8 gram cathode mixtures.
(2) preparation of negative pole
100 weight portion negative electrode active material native graphites, 2 weight portion adhesive polytetrafluoroethylene (PTFE)s, 6 weight portion conductive agent carbon blacks are joined in the 70 weight portion methyl-sulfoxides (DMSO), in de-airing mixer, stir then and form cathode size stable, homogeneous.
This slurry is coated on wide 400 millimeters, the thick 10 microns Copper Foil equably, after 120 ℃ of oven dry, rolling, on cutting machine, cuts and obtain being of a size of 43 millimeters * 355 millimeters * 135 microns negative pole, wherein contain 2.7 gram negative pole compounds.
(3) assembling of battery
With LiPF
6Be configured to LiPF with ethylene carbonate (EC) and diethyl carbonate (DEC)
6Concentration is the solution (wherein, the volume ratio of EC and DEC is 1: 1) of 1.0 mol, obtains nonaqueous electrolytic solution.The negative pole that positive pole, membrane layer, (2) that (1) is obtained obtain is successively with the stacked electrode group that is wound into scroll of up-coiler, the electrode group that obtains is put into the battery case of an end opening, and inject above-mentioned nonaqueous electrolytic solution with the amount of 3.8g/Ah, make lithium ion battery A5 after the sealing.
Comparative Examples 1
This Comparative Examples explanation reference positive pole and lithium ion battery and their preparation method thereof.
It is anodal and comprise this anodal lithium ion battery AC1 to prepare reference according to the content of the method identical with embodiment 1 and each material, and different is that anodal conductive agent is that (specific area is 150 meters to 5 weight portion acetylene blacks
2/ gram) (specific area is 150 meters to 4.5 weight portion acetylene blacks among the replacement embodiment 1
2/ gram) and 0.5 weight portion native graphite (specific area is 40 meters
2/ gram).
Comparative example 2
This Comparative Examples explanation reference positive pole and lithium ion battery and their preparation method thereof.
It is anodal and comprise this anodal lithium ion battery AC2 to prepare reference according to the content of the method identical with embodiment 1 and each material, and different is that anodal conductive agent is that (specific area is 40 meters to 5 weight portion native graphites
2/ gram) (specific area is 150 meters to 4.5 weight portion acetylene blacks among the replacement embodiment 1
2/ gram) and 0.5 weight portion native graphite (specific area is 40 meters
2/ gram).
Comparative example 3
This Comparative Examples explanation reference positive pole and lithium ion battery and their preparation method thereof.
It is anodal and comprise this anodal lithium ion battery AC3 to prepare reference according to the content of the method identical with embodiment 1 and each material, and the specific area of acetylene black in the anodal conductive agent that different is is 75 meters
2/ gram.
Performance test
Battery capacity method of testing below adopting and cycle performance method of testing are measured charge/discharge capacity and the cycle performance of the lithium ion battery AC1-AC3 that lithium ion battery A1-A5 that embodiment 1-5 obtains and Comparative Examples 1-3 obtain respectively, and the result is as shown in table 1.
The battery capacity method of testing: charge with constant voltage charging method, the restriction electric current is 0.1C (65mA), and final voltage is 4.4 volts; Discharge in the constant-current discharge mode, discharging current is 1C (650mA), and the cut-ff voltage of discharge is 3.0 volts, and is recorded in the discharge voltage of the mid point of discharge curve.
Loop test: under 23 ℃ of conditions, with battery respectively with the 1C current charges to 4.2V, with constant-potential charge, cut-off current is 0.05C after voltage rises to 4.4V, shelves 10 minutes; Battery, was shelved 5 minutes to 3.0V with the 1C current discharge.Repeat above step 500 time, obtain the capacity of 100 circulation backs of battery 1C current discharge to 3.0V, by capacity sustainment rate before and after the following formula computation cycles:
Capacity sustainment rate=(the 100th cyclic discharge capacity/cyclic discharge capacity) first * 100%
The cycle performance of the high expression of capacity sustainment rate battery is good, and the cycle performance of the low expression of capacity sustainment rate battery is poor.
Table 1
The embodiment numbering | The battery numbering | Charging capacity (mAh) | Discharge capacity (mAh) | Capability retention (%) after 100 circulations |
Embodiment 1 | A1 | 766 | 693 | 94.1 |
Embodiment 2 | A2 | 762 | 686 | 93.8 |
Embodiment 3 | A3 | 759 | 685 | 93.4 |
Embodiment 4 | A4 | 754 | 674 | 92.4 |
Embodiment 5 | A5 | 752 | 661 | 91.3 |
Comparative example 1 | AC1 | 770 | 694 | 87.3 |
Comparative example 2 | AC2 | 742 | 635 | 94.5 |
Comparative example 3 | AC3 | 750 | 642 | 92.1 |
From the result of table 1 as can be seen, though charging capacity and the discharge capacity of the lithium ion battery AC1 that comparative example 1 obtains are higher, the cycle performance of this battery is poor; Though the cycle performance of the lithium ion battery AC2 that comparative example 2 obtains is better, the charging capacity and the discharge capacity of this battery are low; Cycle performance, charging capacity and the discharge capacity of the lithium ion battery AC3 that comparative example 3 obtains are all not ideal.Compare with the lithium ion battery that Comparative Examples 1-3 obtains, lithium ion battery provided by the invention has higher charging capacity and discharge capacity, keeps excellent cycle performance simultaneously.