Composite mortar of graphene and CNT and preparation method thereof, anode sizing agent and itsMethodTechnical field
The present invention relates to a kind of electrocondution slurry and preparation method thereof, a kind of more particularly to conductive paste for anodeMaterial and preparation method thereof.
Background technology
Protruded as the day of energy and environment problem shows, the development of electric automobile particularly pure electric automobile is imperative.At present, can the bottleneck that restrict Development of Electric Vehicles be to develop inexpensive, safe, environment-friendly secondary cell.Lithium-ion electricPond is acknowledged as most potential power battery of electric vehicle due to the features such as having high-energy-density and high-specific-power concurrently.It is rightFor lithium ion battery, positive plate is the key factor for determining its chemical property, security performance and Costco Wholesale.Lithium fromThe positive electrode of sub- battery is generally transition-metal oxide, such as：LiCoO2、LiNiO2、LiMnO2And LiNixCoyMn(1-x-y)O2Deng, and the phosphate of transition metal, such as LiMPO4(M is Fe or Mn), their electrical conductivity are low, usually semiconductor or absolutelyEdge body, in order to ensure the normal work of lithium ion battery, therefore conductive additive is must be added to during prepared by electrode.
Excellent conductive agent needs to have following feature：First, electrical conductivity is higher, and the material of high conductivity can improve electricityThe migration rate of son；2nd, particle diameter is smaller, and the material of small particle can fill the space of anode material for lithium-ion batteries, make material itBetween contact it is preferable, be easy to the migration of lithium ion；3rd, high-specific surface area, the big material of specific surface area can preferably and positive and negative electrodeMaterial, it is equally easy to Electolyte-absorptive；4th, it is easily dispersed, is easily dispersed in positive electrode prepares slurry process, can be compared withGood mixes with positive electrode；5th, high stability, can be stabilized during lithium ion battery discharge and recharge, noThe reaction with electrolyte can occur and influence the cycle performance of battery.Existing commercial conductive agent is based on carbon material, mainlyIncluding electrically conductive graphite, conductive black and CNT etc., the advantages of above-mentioned conductive agent respectively has itself, but do not possess a kind of excellentThe features described above that conductive agent should possess, can not meet the needs of lithium ion battery conductive agent, therefore, it is necessary to develop newConductive agent.
The content of the invention
It is an object of the invention to for current technology defect, there is provided a kind of more excellent graphene of performance and carbon are receivedThe composite mortar of mitron, the graphene/CNT composite mortars can be applied in lithium ion battery as electrodes conduct agent.The present inventionThe graphene prepared/CNT composite mortars, it is unstable and be improved with material combination defective tightness for graphene slurry,By adding CNT to prevent graphene from reuniting, and conductive network is more efficiently formed by cooperative effect improves electrode and leadElectrical and discharge capacity.
It is a further object of the present invention to provide more excellent anode sizing agent of a kind of performance and preparation method thereof；
It is yet another object of the invention to provide above-mentioned anode pole piece.
The purpose of the present invention implements by the following technical programs：
A kind of composite mortar of graphene and CNT, conductive matter is using graphene and CNT in the slurryCompound, the mass ratio of graphene and CNT contained therein is 3:7-7:3.
As the preferred scheme of the composite mortar of above-mentioned graphene and CNT, contain 1.5wt%- in the slurry3.5wt% CNT, 1.5wt%-3.5wt% graphene, 0.1wt%-1.5wt% dispersion stabilizer, surplus areSolvent.
As the further preferred scheme of the composite mortar of above-mentioned graphene and CNT, contain in the slurry2.5wt% CNT, 2.5wt% graphene, 0.2wt% dispersion stabilizer, surplus are solvent.
According to an aspect of the present invention, the solvent uses 1-METHYLPYRROLIDONE.
According to an aspect of the present invention, the dispersion stabilizer is PVP, polyvinyl alcohol, polypropyleneOne or both of acid esters or APEO mix, preferably PVP and/or polyacrylate.
According to an aspect of the present invention, the BET 200-500m of the graphene2, preferably 200-250m2；Preferably, instituteThe number of plies for stating graphene is less than or equal to 10 layers.
According to an aspect of the present invention, described CNT is caliber 2-20nm, the single wall or more of 1-20 μm of pipe rangeWall carbon nano tube；Preferably, described CNT is caliber 10nm, the single-walled carbon nanotube of 12 μm of pipe range.
According to an aspect of the present invention, viscosity is 5000-8000mPa.s when the slurry is stood.
Above-mentioned graphene and the preparation method of the composite mortar of CNT,
Prepare 3wt%-7wt% graphene slurry；
Prepare 3wt%-7wt% carbon nano tube paste；
Graphene slurry and carbon nano tube paste are pressed 1:1 mass ratio mixing, you can.
According to an aspect of the present invention, the graphene slurry is identical with the solvent of carbon nano tube paste, dispersant hundredDivide more identical than content.
Preferably, the preparation method of the graphene slurry is：Graphene powder is added into the solvent dissolved with dispersant,1-3h is sanded under 8000-12000RPM rotating speed；
Preferably, the preparation method of the carbon nano tube paste is：Carbon nanometer is added into the solvent dissolved with dispersantManage, 1-3h is sanded under 8000-12000RPM rotating speed.
A kind of preparation method of anode sizing agent, PVDF breasts are added into the composite mortar of above-mentioned graphene and CNTLiquid and positive electrode, with 100-300RPM rotating speed, ball milling 1-3h.
Anode sizing agent made from the above method, comprising in composition, comprising：
Lithium nickel cobalt manganese oxide 95.98wt%,
Single wall or multi-walled carbon nanotube 0.5wt%,
Graphene 0.5wt%,
Dispersant 0.02wt%, and
PVDF 3wt%；
Or comprising：
Lithium nickel cobalt manganese oxide 95.98wt%,
Single wall or multi-walled carbon nanotube 0.3wt%,
Graphene 0.7wt%,
Dispersant 0.02wt%, and
PVDF 3wt%；
Or comprising：
Lithium nickel cobalt manganese oxide 95.98wt%,
Single wall or multi-walled carbon nanotube 0.7wt%,
Graphene 0.3wt%,
Dispersant 0.02wt%, and
PVDF 3wt%.
A kind of electrode slice, the anode sizing agent obtained using the above method are prepared.
The concept of the positive electrode occurred in the present invention, refer to the positive electrode used in existing lithium ion battery, includingTernary material, such as：LiFePO4 LiFePO4, lithium and cobalt oxides LiCoO2, lithium nickelate LiNiO2, lithium manganese oxide LiMnO2、Manganese nickel cobalt composite oxides LiMnxNiyCo1-x-yO2, lithium-barium oxide LiV2O4、LiVMO4(M=Ni, Co) or Li1+xV3O8, etc.Deng, and do not terminate in the species enumerated.
The present invention provides graphene/CNT composite mortars and can applied as electrodes conduct agent in lithium ion battery.The present inventionThe graphene prepared/CNT composites, it is unstable and be improved with material combination defective tightness for graphene slurry,By adding CNT to prevent graphene from reuniting, in addition, node of the graphene filling with serving as conductive network among positive electrode,CNT links positive electrode particle and graphene, serves as the branch line of conductive network, is more efficiently formed by both cooperative effectsConductive network, so as to improve electrode conductivuty and discharge capacity.And the electrocondution slurry preparation method of the present invention is simple, it is adapted to bigTechnical scale metaplasia is produced.Meanwhile graphene cost is lower than CNT, the application cost of CNT greatly reduces.ThisThe anode sizing agent provided is provided, electrocondution slurry is compounded using CNT and graphene, in manufactured pole piece, by graphene fill with justThe node of conductive network, CNT link positive electrode particles and graphene are served as among the material of pole, serves as the branch line of conductive network,Only need seldom addition just to make to form efficient conductive network structure between positive electrode, CNT, graphene, improveThe discharge capacity and high rate performance of lithium ion battery.
Shown in Figure 2, the discharge capacity of combined conductive agent sample is higher than simple addition CNT or graphite under equal additionThe sample of alkene, the discharge capacity first of electrode slice of the composite mortar of the present invention with being fabricated to after the compounding of positive electrode is lower, phaseIt is higher with multiplying power under discharge capacity, wherein, work as CNT:GN is 5：When 5, performance is optimal.
Dispersant in composite mortar of the present invention is that (2-5V) is stable in the range of normal charging/discharging voltage；, positive pole slurryIn the preparation of material, using ball milling mixing positive electrode and composite mortar so that positive electrode Surface coating has graphene in pole pieceMicroplate and CNT.The SEM pictures of the anode sizing agent of compounding shown in Figure 1.It can be seen that graphene and carbon are receivedThe combined conductive agent of mitron is intact in positive electrode Surface coating, forms good conductive network.
Brief description of the drawings
Fig. 1 is the SEM pictures of anode sizing agent of the present invention；
Fig. 2 is the button cell different multiplying discharge capacity of the cell of the different conductive agent materials of addition identical.
Embodiment
The preferred embodiments of the present invention are illustrated below, it will be appreciated that preferred embodiment described herein is only usedIn the description and interpretation present invention, it is not intended to limit the present invention.
It is conductive in the slurry An embodiment provides a kind of graphene and the composite mortar of CNTMatter is compound using graphene and CNT, and the mass ratio of graphene and CNT contained therein is 3:7-7:3, such as：3:7、4:7、5:7、6:7、7:7、7:6、7:5、7:4、7:3, etc..
The one side of the present embodiment, the CNT containing 1.5wt%-3.5wt%, 1.5wt%- in the slurry3.5wt% graphene, 0.1wt%-1.5wt% dispersion stabilizer, surplus are solvent.Such as：It is contained in the slurryCNT 1.5wt%, 1.8wt%, 2wt%, 2.1wt%, 2.3wt%, 2.5wt%, 2.7wt%, 3wt%, 3.2wt%,3.5wt%, etc.；Institute graphene-containing 1.5wt%, 1.8wt% in the slurry, 2wt%, 2.1wt%, 2.3wt%, 2.5wt%,2.7wt%, 3wt%, 3.2wt%, 3.5wt%, etc.；Contained dispersion stabilizer 0.1wt%, 0.2wt% in the slurry,0.3wt%, 0.5wt%, 0.6wt%, 0.8wt%, 1wt%, 1.2wt%, 1.3wt%, 1.5wt%, etc..As optimal groupClose, the CNT containing 2.5wt%, 2.5wt% graphene, 0.2wt% dispersion stabilizer in the slurry, surplus isSolvent.
The one side of the present embodiment, the solvent use 1-METHYLPYRROLIDONE.
The one side of the present embodiment, the dispersion stabilizer are PVP, polyvinyl alcohol, polyacrylic acidOne or both of ester or APEO mix, preferably PVP and/or polyacrylate.
The one side of the present embodiment, the BET 200-500m of the graphene2, such as：200m2、210m2、220m2、230m2、240m2、250m2、270m2、290m2、300m2、310m2、330m2、345m2、350m2、365m2、380m2、400m2、450m2、475m2、500m2, etc.；It is preferred that 200-250m2, such as：200m2、205m2、210m2、220m2、222m2、230m2、236m2、240m2、243m2、250m2, etc..
The one side of the present embodiment, the number of plies of the graphene are less than or equal to 10 layers, such as：1 layer graphene, 2 layers of stoneBlack alkene, 5 layer graphenes, 7 layer graphenes, 10 layer graphenes, etc..
The one side of the present embodiment, described CNT are caliber 2-20nm, the single wall of 1-20 μm of pipe range or more wallsCNT；Such as：Caliber 2nm, 20 μm of pipe range single-walled carbon nanotube, caliber 20nm, the multi-walled carbon nanotube of 1 μm of pipe range,Caliber 5nm, 10 μm of pipe range single-walled carbon nanotube, caliber 12nm, the single-walled carbon nanotube of 7 μm of pipe range, caliber 15nm, pipe range 10μm multi-walled carbon nanotube, etc.；Preferably, described CNT is caliber 10nm, the single-walled carbon nanotube of 12 μm of pipe range.
The one side of the present embodiment, viscosity is 5000-8000mPa.s when the slurry is stood.
An alternative embodiment of the invention, there is provided above-mentioned graphene and the preparation side of the composite mortar of CNTMethod,
Prepare 3wt%-7wt% graphene slurry；
Prepare 3wt%-7wt% carbon nano tube paste；
Graphene slurry and carbon nano tube paste are pressed 1:1 mass ratio mixing, you can.
According to an aspect of the present invention, the graphene slurry is identical with the solvent of carbon nano tube paste, dispersant hundredDivide more identical than content.
The one side of the present embodiment, the preparation method of the graphene slurry are：Into the solvent dissolved with dispersantGraphene powder is added, 1-3h is sanded under 8000-12000RPM rotating speed.Such as：Under 8000RPM rotating speed be sanded 3h,Under 12000RPM rotating speed be sanded 1h, 10000RPM rotating speed under be sanded 2h, 9000RPM rotating speed under be sanded 1.5h,2.5h is sanded under 11000RPM rotating speed, etc..
The one side of the present embodiment, the preparation method of the carbon nano tube paste are：To the solvent dissolved with dispersantMiddle addition CNT, 1-3h is sanded under 8000-12000RPM rotating speed.Such as：Under 8000RPM rotating speed be sanded 3h,Under 12000RPM rotating speed be sanded 1h, 10000RPM rotating speed under be sanded 2h, 9000RPM rotating speed under be sanded 1.5h,2.5h is sanded under 11000RPM rotating speed, etc..
An alternative embodiment of the invention, there is provided a kind of preparation method of anode sizing agent, to above-mentioned graphene and carbonPVDF emulsions and positive electrode are added in the composite mortar of nanotube, with 100-300RPM rotating speed, ball milling 1-3h.Such as：With100RPM rotating speed, ball milling 3h；With 300RPM rotating speed, ball milling 1h；With 200RPM rotating speed, ball milling 2h；With turning for 150RPMSpeed, ball milling 1.5h；With 200RPM rotating speed, ball milling 2.5h；Deng.
An alternative embodiment of the invention, there is provided anode sizing agent made from the above method, comprising in composition, comprising：
Lithium nickel cobalt manganese oxide 95.98wt%,
Single wall or multi-walled carbon nanotube 0.5wt%,
Graphene 0.5wt%,
Dispersant 0.02wt%, and
PVDF 3wt%；
Or comprising：
Lithium nickel cobalt manganese oxide 95.98wt%,
Single wall or multi-walled carbon nanotube 0.3wt%,
Graphene 0.7wt%,
Dispersant 0.02wt%, and
PVDF 3wt%；
Or comprising：
Lithium nickel cobalt manganese oxide 95.98wt%,
Single wall or multi-walled carbon nanotube 0.7wt%,
Graphene 0.3wt%,
Dispersant 0.02wt%, and
PVDF 3wt%.
Another embodiment of the present invention, there is provided a kind of electrode slice, using the anode sizing agent preparation that the above method obtainsInto.
Embodiment 1：
940 grams of 1-METHYLPYRROLIDONEs are weighed, add 10 grams of PVPs, stirring and dissolving；
Solution is divided into 2 parts of identical, portion adds 25 grams of multi-walled carbon nanotubes, its pipe range<It is 10 μm, 10000RPM, huskyMill 1h obtains slurry 1；Portion adds 25 grams of graphenes, and its specific surface area is about 225m2/g；10000RPM, sand mill 1h are starchedMaterial 2；
Slurry 1 is compounded after being mixed with slurry 2 by ball milling (200RPM, ball milling 2h) and lithium nickel cobalt manganese oxide, compoundIn the mass percent of each composition be：Lithium nickel cobalt manganese oxide: multi-walled carbon nanotube: graphene: dispersant: PVDF=95.98%: 0.5%: 0.5%: 0.02%: 3%, make button electricity, test battery performance.(join with pure nano-carbon tube slurry simultaneouslySee comparative example) contrast.Fig. 1 is compound SEM photograph, and button cell different multiplying battery performance is as shown in Figure 2.
Embodiment 2：
940 grams of 1-METHYLPYRROLIDONEs are weighed, add 10 grams of PVPs, stirring and dissolving；
Solution is divided into 2 parts of identical, portion adds 15 grams of multi-walled carbon nanotubes, its pipe range<It is 10 μm, 10000RPM, huskyMill 1h obtains slurry 1；Portion adds 35 grams of graphenes, and its specific surface area is about 225m2/g；10000RPM, sand mill 1h are starchedMaterial 2；
The slurry that slurry 1 obtains after being mixed with slurry 2 is answered by ball milling (100RPM, ball milling 3h) with lithium nickel cobalt manganese oxideMatch somebody with somebody, the mass percent of each composition is in compound：Lithium nickel cobalt manganese oxide: multi-walled carbon nanotube: graphene: dispersant:PVDF=95.98%: 0.3%: 0.7%: 0.02%: 3%, make button electricity, test battery performance.Starched simultaneously with pure nano-carbon tubeMaterial contrasts (referring to comparative example).Button cell different multiplying battery performance is as shown in Figure 2.
Embodiment 3：
940 grams of 1-METHYLPYRROLIDONEs are weighed, add 10 grams of PVPs, stirring and dissolving；
Solution is divided into 2 parts of identical, portion adds 35 grams of multi-walled carbon nanotubes, its pipe range<It is 10 μm, 10000RPM, huskyMill 1h obtains slurry 1；Portion adds 15 grams of graphenes, and its specific surface area is about 400m2/g；10000RPM, sand mill 2h are starchedMaterial 2；
The slurry that slurry 1 obtains after being mixed with slurry 2 is answered by ball milling (300RPM, ball milling 1h) with lithium nickel cobalt manganese oxideMatch somebody with somebody, the mass percent of each composition is in compound：Lithium nickel cobalt manganese oxide: multi-walled carbon nanotube: graphene: dispersant:PVDF=95.98%: 0.7%: 0.3%: 0.02%: 3%, make button electricity, test battery performance.Starched simultaneously with pure nano-carbon tubeMaterial contrasts (referring to comparative example).Button cell different multiplying battery performance is as shown in Figure 2.
Embodiment 4：
940 grams of 1-METHYLPYRROLIDONEs are weighed, add 10 grams of PVPs, stirring and dissolving；
Solution is divided into 2 parts of identical, portion adds 35 grams of multi-walled carbon nanotubes, its pipe range<10 μm, 8000RPM, sand mill3h obtains slurry 1；Portion adds 15 grams of graphenes, and its specific surface area is about 400m2/g；12000RPM, sand mill 1h obtain slurry2；
The slurry that slurry 1 obtains after being mixed with slurry 2 is answered by ball milling (150RPM, ball milling 2h) with lithium nickel cobalt manganese oxideMatch somebody with somebody, the mass percent of each composition is in compound：Lithium nickel cobalt manganese oxide: multi-walled carbon nanotube: graphene: dispersant:PVDF=95.98%: 0.7%: 0.3%: 0.02%: 3%.
Embodiment 5：
940 grams of 1-METHYLPYRROLIDONEs are weighed, add 10 grams of PVPs, stirring and dissolving；
Solution is divided into 2 parts of identical, portion adds 35 grams of multi-walled carbon nanotubes, its pipe range<10 μm, 1200RPM, sand mill3h obtains slurry 1；Portion adds 15 grams of graphenes, and its specific surface area is about 400m2/g；8000RPM, sand mill 1h obtain slurry 2；
The slurry that slurry 1 obtains after being mixed with slurry 2 is answered by ball milling (100RPM, ball milling 1h) with lithium nickel cobalt manganese oxideMatch somebody with somebody, the mass percent of each composition is in compound：Lithium nickel cobalt manganese oxide: multi-walled carbon nanotube: graphene: dispersant:PVDF=95.98%: 0.7%: 0.3%: 0.02%: 3%.
Comparative example：Pure nano-carbon tube slurry, i.e., the mass percent of each composition are：Lithium nickel cobalt manganese oxide: CNT: scatteredAgent: PVDF=95.98%: 1%: 0.02%: 3%.