A kind of high performance three-dimensional CNT composite negative pole material and its preparation method and application
Technical field
The present invention relates to technical field of lithium ion battery negative, and in particular to a kind of high performance three-dimensional CNT is answered
Close negative material and its preparation method and application.
Background technology
Lithium ion battery has that open-circuit voltage is high, energy density big, long service life, memoryless effect, of low pollution and
The advantages of self-discharge rate is small, it is better than other traditional secondary batteries on overall performance, is considered as unanimously various portable electrics
Sub- equipment and ideal power supply used for electric vehicle.Although conventional lithium ion battery negative material graphite good cycling stability with
And cost performance is higher, but because its charging and discharging capacity is relatively low, volume and capacity ratio is even more no advantage, it is difficult to meet dynamical system
The system particularly requirement of electric motor car and hybrid electric vehicle to cell high-capacity.Therefore exploitation has height ratio capacity, high charge-discharge
Efficiency, the great urgency of novel cathode material for lithium ion battery of long circulation life.
In the research of new non-carbon negative material, the pure metals such as silicon, tin, germanium, metal oxide and composition metal
Oxide material with theoretical embedding lithium capacity higher because increasingly attracting attention.If the negative material of these high power capacity can reach
Degree of being practical, will be such that the range of application of lithium ion battery widens significantly.But, the negative material of these high power capacity is mostly electric
Conductance is relatively low, and under the conditions of high level removal lithium embedded, there is serious bulk effect, causes the cyclical stability of electrode poor.
For the volume efficiency of the negative material of these high power capacity, it is combined with the carrier with elasticity and stable performance, buffers silicon
Volume Changes, the effective way of its cyclical stability is improved while high power capacity will be to maintain.Carbon is due to possessing lighter matter
Amount, preferable electric conductivity, relatively low intercalation potential is wide many advantages, such as Volume Changes are small and cheap during deintercalation etc.
It is general to be used in anode material.
CNT, due to possessing mechanical strength higher, preferable electric conductivity is once widely applied to electrode material
In material.But due to the carbon material relatively low limitation of theoretical capacity in itself, electrode capacity prepared by independent CNT it is relatively low into
To restrict the major obstacle of its development.CNT is mutually combined with the negative material with theoretical capacity high, two can be combined
The advantage of person, prepares the lithium cell negative pole material with superior performance.Nano-silicon and CNT are scattered in phenol by Zhou et al.
In the solution of urea formaldehyde, by preparing electrode material after Pintsch process, can keep 711 mAh/g after the circulation of 20, the electrode can
Inverse capacity(J. Alloys Compd. 2010, 493(1-2): 636-639.).Yue et al. is by mixing nano silica fume and carbon
Nanotube, by the use of sodium carboxymethylcellulose as adhesive, suction filtration dries after annealing and is prepared from compound paper electrode.Due to carboxylic first
The carbonization of base sodium cellulosate causes the deflation of structure so that silicon nanoparticle is compressed in carbon nano tube structure, and silicon is formed
Contact well, the effective expansion for suppressing silicon volume.Remain to keep 942 mAh/g after prepared 30 circulations of compound electric paper
Reversible capacity, under the electric current of 500 mA/g, average reversible capacity is remained to up to 650 mAh/g(Electrochim. Acta,
76, 326–332, 2012.).But the method system for up to this point, being mixed using CNT and high power capacity active material
All can't be of great satisfaction for aspects such as the improvement of combination electrode capacity and cycle performance for going out.To find out its cause, crucial
It is:1)CNT and the compound sex chromosome mosaicism that is uniformly dispersed of high power capacity active material.In the method for common mixing, due to compound
The electrostatic attraction of material both sides is limited, and active material uniformly can not be scattered in the spacial framework of CNT, caused
CNT can not effectively improve the bulk effect of high power capacity active material;2)Between CNT and high power capacity active material
Can not effectively contact, cause charge transfer less efficient.
The content of the invention
Goal of the invention:First technical problem to be solved of the invention there is provided a kind of high performance three-dimensional carbon nanometer
The preparation method of pipe composite negative pole material.
Second technical problem to be solved of the invention there is provided a kind of high performance three-dimensional CNT Compound Negative
Pole material.
3rd technical problem to be solved of the invention there is provided a kind of high performance three-dimensional CNT Compound Negative
Application of the pole material in terms of combination electrode is prepared.
Technical scheme:In order to solve the above-mentioned technical problem, it is compound the invention provides a kind of high performance three-dimensional CNT
The preparation method of negative material, it is modified with LBL self-assembly by using carboxylic carbon nano-tube as three-dimensional network skeleton
High power capacity material be active material, carboxylic carbon nano-tube is uniformly mixed with active material by the effect of electrostatic attraction
Close, be then used as three-dimensional clad containing the carbon source that miscellaneous element N or S adulterates by in-stiu coating prepares height via high-temperature process
Performance three dimensional carbon nanotubes composite negative pole material.
A kind of preparation method of high performance three-dimensional CNT composite negative pole material, specifically includes following steps:
1) CNT is carried out into carboxylated treatment;
2)Carboxylic carbon nano-tube is added to the water, ultrasonic disperse prepares carboxylic carbon nano-tube solution;
3)The material of the modified high power capacity of LBL self-assembly is added to the water, ultrasonic disperse is uniformly mixing to obtain mixed
Close liquid;
4)By step 3)Resulting dispersed mixed liquor pours into step 2)Carboxylic carbon nano-tube solution in, stirring
Stood after uniform, remove carboxylic carbon nano-tube/active material suspension that lower floor is obtained after the clear aqueous solution of upper strata;
5)Under condition of ice bath, to step 4)Carboxylic carbon nano-tube/active material suspension in conducting polymer is added dropwise
Thing monomer, ultrasonic disperse is uniformly mixing to obtain mixed solution;
6)By step 5)Mixed solution first under ice bath stir, adjust pH value, then be added dropwise containing oxidant the aqueous solution,
It is stirred overnight under ice bath, carboxylic carbon nano-tube/active material/polymer composites is obtained by suction filtration;
7)By step 6)Carboxylic carbon nano-tube/active material/polymer composites protect gas under high-temperature process
Prepare high performance three-dimensional CNT composite negative pole material.
The step 1)Carboxylated process step is:First by CNT, 80 DEG C of backflows remove remaining gold in concentrated hydrochloric acid
Category ion, then 60 DEG C of ultrasound 3h of the concentrated sulfuric acid/salpeter solution that volume ratio is 3/1 will be used, it is washed till neutrality with a large amount of deionized waters
After drying afterwards.
The step 3)The modified step of LBL self-assembly is:With anionic polyelectrolyte diallyl dimethyl chlorination
Ammonium(PDDA)With cationic polyelectrolyte kayexalate(PSS)As raw material, layer is carried out in the material surface of high power capacity
Layer assembling, changes the charge property of active material surface.
The material of the high power capacity is one or more in nano silica fume, germanium powder, glass putty;Or nano-oxide powder includes
One or more in tin ash, tungsten oxide, zinc oxide, indium oxide;Or nano composite metal oxide includes zinc manganate, cobalt
One or more in sour manganese, Manganese Ferrite powder.
Described carboxylic carbon nano-tube is in SWCN, double-walled carbon nano-tube or multi-walled carbon nano-tubes
Kind.Preferably cheap multi-walled carbon nano-tubes.
Described carboxylic carbon nano-tube is 1 with the mass ratio of active material:5~1:10.
The step 5)Middle conducting polymer monomer is the one kind in aniline monomer, pyrrole monomer, thiophene monomer, described to lead
The addition of electric polymer monomer is 0.5~2 times of the quality of active material, step 6)The addition of middle oxidant is polymer
2.4~5 times of the quality of monomer, oxidant is (NH4)2S2O8。
The step 7)In high-temperature process be:500~800 DEG C are carried out in a vacuum or inert atmosphere, inert atmosphere
It is Ar, Ar/H2Gaseous mixture or He.
The high performance three-dimensional CNT composite negative pole material that above-mentioned preparation method is prepared.
Application of the above-mentioned high performance three-dimensional CNT composite negative pole material in terms of combination electrode is prepared.
Beneficial effect:The present invention improves obvious to the cycle performance of active material, and can be according to control CNT and work
The capacity of the ratio controllable adjustment composite of property material.Additionally, solvent used in the present invention is water, it is environment-friendly, and weight
Renaturation is good, with low cost, and with preferable scale application potential, industrial prospect is good.Preparing raw material of the present invention is cheap, behaviour
Make process is simple, high income, the charge-discharge performance of material is excellent, is easy to industrialized production.
Brief description of the drawings
Fig. 1 is the preparation technology schematic flow sheet of high performance three-dimensional CNT composite negative pole material;
Fig. 2 is the electromicroscopic photograph of sample prepared by embodiment 1 ~ 3.A () is that carbonization is prepared after Si- polyanilines are combined
The TEM figures of Si/C composites;(b/c) it is TEM and the SEM figure being combined with CNT after Si modified by nano particles;D () is system
The SEM figures of the three dimensional carbon nanotubes Si base composite negative pole materials for obtaining;(e-h) it is obtained three dimensional carbon nanotubes Si base composite negative poles
The TEM figures of material;(i/j) it is three dimensional carbon nanotubes SnO2The compound TEM figures of base;(k/l) it is three dimensional carbon nanotubes ZnFe2O4Base
Compound TEM figures;
Fig. 3 (a) is the cycle performance figure of Si and MWCNTS electrode materials after Si, oxidation processes;B () is Si/MWCNTS
And the cycle performance figure of Si/C combination electrode materials;C () is three dimensional carbon nanotubes Si bases composite negative pole material obtained in embodiment 1
The cycle performance figure under 200 mA/g and 400 mA/g of material;D () is multiple for three dimensional carbon nanotubes Si bases obtained in embodiment 1
Close the high rate performance figure of negative material;
Fig. 4 is obtained three dimensional carbon nanotubes SnO for embodiment 22Electrode is in 400 mAg prepared by base composite negative pole material-1Charging and discharging currents density under cycle performance test curve;
Fig. 5 is obtained three dimensional carbon nanotubes ZnFe for embodiment 32O4Electrode is 400 prepared by base composite negative pole material
mA·g-1Charging and discharging currents density under cycle performance test curve.
Specific embodiment
Embodiment of the present invention is further described below in conjunction with accompanying drawing, following examples are being with technical solution of the present invention
Under the premise of implemented, give detailed implementation method and specific operating process, but protection scope of the present invention is not limited to
Following embodiments.
It is the active material of 200 below nm that granularity is used in following examples, and in advance 80 DEG C times in concentrated hydrochloric acid
Flow and then with 60 DEG C of ultrasound 3h of the concentrated sulfuric acid/salpeter solution that volume ratio is 3/1, dried after being washed till neutrality with a large amount of deionized waters
The carboxylation multi-walled carbon nano-tubes (external diameter is 60-100nm, Nanjing pioneer's nanosecond science and technology company) for obtaining afterwards, the average mark of PSS
Son amount is 70000.And implement in accordance with the technological process shown in Fig. 1.
Embodiment 1
1)Two parts of the aqueous solution 200mL of the NaCl containing 1 wt.%PDDA and 0.2M is prepared, ultrasonic disperse is allowed to for 10 minutes
It is dispersed;The mL of the aqueous solution 200 for preparing 1 wt.%PSS is a, and ultrasonic disperse is allowed to dispersed in 10 minutes;By the warp of 1g
Cross the Si powder of surface oxidation treatment(Particle diameter is 100~200 nm), sequentially pass through PDDA-PSS-PDDA treatment and be modified, filtering,
70 DEG C of 2 h vacuum drying, grinds after drying, mark storage;
2)Take the above-mentioned Si powder 0.1g being modified to be scattered in again in 200 mL deionized waters, ultrasonic disperse makes for 2 hours
It is dispersed;
3)By in 0.02 g carboxylic carbon nano-tubes, 200 mL deionized waters of addition, ultrasonic disperse makes carboxylated in 2 hours
CNT is dispersed;
4)In the case of high-speed stirred, the dispersion that the above-mentioned Si powder solution being modified pours into carboxylic carbon nano-tube is taken
Liquid, is stood after continuing to stir 2 hours, and the carboxylic carbon nano-tube/active material suspension of lower floor is taken out using separatory funnel, will
Be settled to 50 mL;
5)The aniline monomer for taking 0.2mL is scattered in the deionized water of 40mL, the ultrasonic agitation 1h in frozen water.By above-mentioned step
Rapid 4)Carboxylic carbon nano-tube/active material Si suspensions add above-mentioned aniline monomer dispersion liquid, the magnetic under condition of ice bath
Power is stirred 1 hour.Then the pH value for adjusting solution with concentrated hydrochloric acid is 3 or so, continues to stir 20min.10 mL are prepared containing (NH4)2S2O8 The aqueous solution of 0.75g, by the above-mentioned solution of addition in.Condition of ice bath is kept, 24 h are reacted.By mixture suction filtration, use
Deionized water is washed 3 times, is dried, grinding, and 800 DEG C of 3 h sintering prepares three dimensional carbon nanotubes/Si composite negative poles under Ar gas
Material.Described carboxylic carbon nano-tube is 1 with the mass ratio of active material Si:5, the addition of the aniline monomer is activity
2 times of the quality of material Si, described oxidant (NH4)2S2O8Addition be 3.7 times of quality of aniline monomer.Will
After material after sintering is fully ground, and carbon black and carboxymethylcellulose calcium are well mixed, film according to 60: 20: 20 ratio
60 DEG C of vacuum drying 4h, prepare combination electrode afterwards.It is to electrode, with poly- with lithium piece by electrode in 2025 battery cases
Vinyl film is barrier film, with 1M LiPF6EC/DEC (v/v=1/1) carries out constant current charge-discharge survey for electrolyte assembled battery
Examination.Test result is referring to experimental example.
Embodiment 2
1)Two parts of the aqueous solution 200mL of the NaCl containing 1 wt.%PDDA and 0.2M is prepared, ultrasonic disperse is allowed to for 10 minutes
It is dispersed;The mL of the aqueous solution 200 for preparing 1 wt.%PSS is a, and ultrasonic disperse is allowed to dispersed in 10 minutes;By the burning of 1g
The SnO for tying2Nano particle(50 nm), sequentially passing through PDDA-PSS-PDDA treatment and be modified, filtering, 70 DEG C of 2 h vacuum is done
It is dry.Ground after drying, mark storage;
2)Take the above-mentioned SnO being modified2Nano particle 0.2g is scattered in 200 mL deionized waters again, ultrasonic disperse 2
Hour is allowed to dispersed;
3)By in 0.02 g carboxylic carbon nano-tubes, 200 mL deionized waters of addition, ultrasonic disperse makes carboxylated carbon in 2 hours
Nanotube is dispersed;
4)In the case of high-speed stirred, the above-mentioned SnO being modified is taken2Nanoparticles solution pours into carboxylation CNT
Dispersion liquid, continue stir 2 hours after stand, using separatory funnel take out lower floor carboxylic carbon nano-tube/active material hang
Turbid liquid, 50 mL are settled to by it;
5)The pyrrole monomer for taking 0.1mL is scattered in the deionized water of 40mL, the ultrasonic agitation 1h in frozen water.By above-mentioned step
Rapid 4)Carboxylic carbon nano-tube/active material SnO2Suspension is added in above-mentioned pyrrole monomer dispersion liquid, under condition of ice bath
Magnetic agitation 30 minutes.Then the pH value for adjusting solution with concentrated hydrochloric acid is 3 or so, continues to stir 20min.10 mL are prepared to contain
(NH4)2S2O8 The aqueous solution of 0.495 g, by the above-mentioned solution of addition in.Condition of ice bath is kept, is reacted 24 hours.Will mixing
Thing suction filtration, is washed with deionized 3 times, dries, and after grinding, 600 DEG C of 5 h sintering prepares three-dimensional carbon nanometer under Ar gas
Pipe/SnO2Composite negative pole material.Described carboxylic carbon nano-tube and active material SnO2Mass ratio be 1:10, the pyrroles
The addition of monomer is about active material SnO20.5 times of quality, described oxidant (NH4)2S2O8Addition be pyrroles
5 times of the quality of monomer.After material after sintering is fully ground, and carbon black and carboxymethylcellulose calcium are according to 60: 20: 20
Ratio, is well mixed, and 60 DEG C of 4 h of vacuum drying, prepare combination electrode after film.By electrode in 2025 battery cases,
It is to electrode, with polyethylene film as barrier film, with 1M LiPF with lithium piece6EC/DEC (v/v=1/1) assembles electricity for electrolyte
Pond carries out constant current charge-discharge test.Test result is referring to experimental example.
Embodiment 3
1)Two parts of 200 mL of the aqueous solution of the NaCl containing 1 wt.%PDDA and 0.2M is prepared, ultrasonic disperse makes for 10 minutes
It is dispersed;The mL of the aqueous solution 200 for preparing 1 wt.%PSS is a, and ultrasonic disperse is allowed to dispersed in 10 minutes;By 1g's
Sintered ZnFe2O4Nano particle(About 50 nm), sequentially passing through PDDA-PSS-PDDA treatment and be modified, filtering, 70 DEG C of 2 h is true
Sky is dried.Ground after drying, mark storage;
2)Take the above-mentioned 0.1g ZnFe being modified2O4Nano particle is scattered in 200 mL deionized waters again, ultrasound point
Dissipate and be allowed to dispersed in 2 hours;
3)By in 0.01 g carboxylic carbon nano-tubes, 200 mL deionized waters of addition, ultrasonic disperse makes carboxylated in 2 hours
CNT is dispersed;
4)In the case of high-speed stirred, the above-mentioned 0.1gZnFe being modified is taken2O4Nanoparticles solution pours into carbon nanometer
The dispersion liquid of pipe, is stood after continuing to stir 2 hours, and the CNT/active material suspension of lower floor is taken out using separatory funnel,
It is settled to 50 mL;
5)The thiophene monomer for taking 0.1mL is scattered in the deionized water of 40mL, the ultrasonic agitation 1h in frozen water.By above-mentioned step
Rapid 4)Carboxylic carbon nano-tube/active material ZnFe2O4Suspension is added in above-mentioned thiophene monomer dispersion liquid, in condition of ice bath
Lower magnetic agitation 1 hour.Then the pH value for adjusting solution with concentrated hydrochloric acid is 3 or so, continues to stir 20min.10 mL are prepared to contain
(NH4)2S2O8 The aqueous solution of 0.322 g, by the above-mentioned solution of addition in.Condition of ice bath is kept, is reacted 24 hours.Will mixing
Thing suction filtration, is washed with deionized 3 times, dries, and after grinding, 500 DEG C of 3 h sintering prepares three-dimensional carbon nanometer under Ar gas
Pipe/ZnFe2O4Composite negative pole material.Described carboxylic carbon nano-tube and active material ZnFe2O4Mass ratio be 1:10, institute
The addition for stating thiophene monomer is active material ZnFe2O41.3 times of quality, described oxidant (NH4)2S2O8Addition
It is 2.4 times of the quality of thiophene monomer.After material after sintering is fully ground, and carbon black and carboxymethylcellulose calcium are according to 60
: 20: 20 ratio, it is well mixed, 60 DEG C of 4 h of vacuum drying, prepare combination electrode after film.By electrode 2025
It is to electrode, with polyethylene film as barrier film, with 1M LiPF with lithium piece in battery case6EC/DEC (v/v=1/1) is electrolysis
Liquid assembled battery carries out constant current charge-discharge test.Test result is referring to experimental example.
Experimental example:
Tested to present invention preparation to the pattern of composite and by cycle performance below by SEM and TEM photos
The chemical property of composite tested and characterized.
1st, tem analysis
Fig. 2 is the TEM photos of sample prepared by the embodiment of the present invention 1 ~ 3 and associated sample.Fig. 2 (a) is Si- polyanilines
Be carbonized the TEM figures of the Si/C composites for preparing after compound, it can be seen that nano Si material has one unformed on surface
Carbon-coating is present;(b/c) it is TEM and the SEM figure being combined with carboxylic carbon nano-tube after Si modified by nano particles, it can be seen that Si receives
Rice grain is uniformly dispersed in the middle of carboxylic carbon nano-tube network;D () is obtained three dimensional carbon nanotubes Si base composite negative poles
The SEM figures of material, it can be seen that surface is presented homogeneous carbon network cladding characteristic;(e-h) it is obtained three dimensional carbon nanotubes Si
The TEM figures of base composite negative pole material, it is upper it will be clear that by carbon between Si nano particles and carboxylic carbon nano-tube from figure
Connect, form three-dimensional network structure.(i/j) it is three dimensional carbon nanotubes SnO2The compound TEM figures of base, can be clear from figure
See SnO to Chu2Connected by carbon between nano particle and carboxylic carbon nano-tube, form three-dimensional network structure;(k/l)
It is three dimensional carbon nanotubes ZnFe2O4The compound TEM figures of base, it is upper it will be clear that ZnFe from figure2O4Nano particle and carboxylated
Connected by carbon between CNT, form three-dimensional network structure.
2nd, cycle performance test
Fig. 3 (a) is Si, the cycle performance figure of the Si and MWCNTS electrode materials of oxidation processes, is compared as can be known from Figure
The Si electrode materials of MWCNTS, Si and oxidation processes have an initial capacity higher, but the cyclical stability of MWCNTS electrodes
Preferably, so silicon and carboxylic carbon nano-tube are combined, it is possible to prepare capacity high and good cycling stability answer
Composite electrode;B () is the cycle performance figure of Si/MWCNTS and Si/C combination electrode materials, compared to the electrode with naked silicon, circulation is steady
It is qualitative to be improved;C () is three dimensional carbon nanotubes Si bases composite negative pole material obtained in embodiment 1 in 200 mA/g and 400
Cycle performance figure under mA/g, preparation-obtained combination electrode shows preferable cyclical stability, after 100 circulate
Remain to keep 1141 and 1087 mAhg respectively-1Discharge capacity;D () is multiple for three dimensional carbon nanotubes Si bases obtained in embodiment 1
The high rate performance figure of negative material is closed, in 10000mAg-1Electric current under, still have about 380 mAhg-1Discharge capacity, far
Better than the battery performance of conventional graphite negative pole.
Fig. 4 is three dimensional carbon nanotubes SnO prepared by embodiment 22Base composite negative pole material cycle performance test curve, relatively
In the SnO not being wrapped by2The electrode of material, the electrode after being combined shows larger performance improvement, is discharged after 100 circulations and held
Measure from 171 mAhg-1Improve to 971 mAhg-1。
Fig. 5 is three dimensional carbon nanotubes ZnFe prepared by embodiment 32O4The cycle performance test curve of base composite negative pole material,
Relative to the ZnFe not being wrapped by2O4The electrode of material, the electrode after being combined equally shows larger performance improvement, and 100 are followed
Discharge capacity is from 73 mAhg after ring-1Improve to 858 mAhg-1。
In sum, in the three dimensional carbon nanotubes base composite negative pole material that prepared by the present invention, nano particle is successfully wrapped
Overlay in carbon material, porous and hollow structure causes that active material particle great volumetric expansion in charge and discharge process is obtained
To effective suppression, three-dimensional network structure can accelerate electronics conduction, so as to greatly improve the cycle performance of material.