Background technology
[0002] PVDF is a kind of partially fluorinated, hemicrystalline polymkeric substance, has the characteristics such as excellent chemical resistant properties, thermomechanically performance, weathering resistance, also has the solvent resistance that appropriateness is balanced, good forming process, good toughness simultaneously.There is in addition good electrical property, be therefore widely used in the fields such as mould material, coating, lithium electricity, tubing cable.
Lithium cell is the current the highest chargeable chemical cell of technology in the world, and more than ten years development recently rapidly, is mainly used in mobile phone, electronic product and power tool.Lithium-ions battery positive and negative electrode for the meeting of volume in charge and discharge process dilation, require binding agent can play certain shock absorption, the requirement that therefore must meet as lithium ion battery binding agent is: (1) has enough cohesive strengths, prevent that active substance from coming off from current collector, or cracking in battery assembling process; (2) binding agent can not be dissolved in for the organic solvent as electrolytic solution, but can be dissolved in the solvent of making current collector top coat; (3), at operating voltage range, binding agent can not be oxidated or reduced.
Because the adhesive property of PVDF homopolymer is limited, be difficult to meet the needs of high-capacity lithium battery, therefore need to carry out modification to PVDF improves its adhesive property.Functional modification can be realized by the surface-functionalized acquisition graft copolymer of PVDF material, by produce free radical on PVDF molecular chain, carry out graft polymerization reaction acquisition, but can there are some uncontrolled side reactions in this process, even molecular chain ruptures, and causes the mechanical property of PVDF to decline to a great extent.Another kind of method of modifying is modification by copolymerization, has following report in prior art:
It is comonomer that Japanese Patent Te Open 2003-155313 be take (methyl) vinylformic acid shrink ester, guarantees that binding agent has good resistance to solvent resistance toheat, promotes the bounding force of binding agent, improves stripping strength.For example in VDF, add 1wt%2-glycidyl methacrylate (2M-GMA), suspension copolymerization, this multipolymer is that the stripping strength of the electrode prepared compared with PVDF homopolymer of the electrode of binding agent improves 5 times, and the stripping strength that in propylene carbonate, high temperature soaked after 5 days is high 14 times.
It is comonomer that Japanese Patent Te Open 2001-19896 be take toxilic acid monoesters class.The monomethyl maleate (MMM) that adds 1wt% in VDF, suspension copolymerization, this multipolymer is that the electrode of binding agent improves 4 times compared with PVDF homopolymer stripping strength, and in the electrolytic solution of propylene carbonate/glycol dimethyl ether=1/1, high temperature soaked after one week, and stripping strength is high 5 times.
Great Jin, in the many pieces of patents such as the flat 9-161804 of Japanese Patent, flat 10-233217, special Open 2001-223011, studies the copolymerization of VDF and TFE and perfluorovinyl sulfide ethers monomer, and the ratio control of VDF is between 60-80%.
In Wu Yu Chinese patent CN1714465A, mentioned the method for VDF with the monomer copolymerization that contains hydroxyl and carboxyl, enumerated the monomers such as acrylate, toxilic acid monoesters, glycidyl allyl ether, main purpose is to use safety for improving bounding force and the battery of binding agent.
The comonomer of mentioning in great Jin Chinese patent CN1240053A and its monomer mentioned in the open patent 2001-223011 of Japanese publication are basically identical, and adding of TFE improved swelling resistance performance, the adding in order to promote cohesive force of the 3rd monomer.
In Samsung SDI Chinese patent CN101188283A, adopt the multipolymer of VDF and HFP, with other mineral binder bond acting in conjunction, suppress the side reaction of positive electrode material and electrolytic solution.
In Su Wei Chinese patent CN101679563A, mention VDF and the copolymerization of (methyl) Acrylic Acid Monomer, and guarantee that 40% polar monomer is uniformly distributed, in order to keep mechanical property, the chemical stability of PVDF, improve cohesive force simultaneously.
Summary of the invention
The inventor studies the PVDF material of high Binder Properties, discovery is because connection alkene ether compounds has unique continuous double bond structure, carry out after copolymerization with VDF, in the polymerisate of gained, exist two keys that can continue reaction, can be used as the basis of next step crosslinking reaction.Further, by after light-initiated pair of key radical polymerization of ultraviolet lamp, realize being cross-linked between copolymer molecule, form the crosslinked with high bond strength.
The invention provides the novel vinylidene fluoride copolymers of a kind of high viscosity self-crosslinking, contain vinylidene fluoride monomers and at least one modification connection alkene ether compounds, described modification connection alkene ether compounds has following structural formula (I):
Wherein:
R
1, R
2, R
3and R
4independently selected from hydrogen atom, halogen, C
1-C
8the C that alkyl, at least one hydrogen atom are replaced by halogen
1-C
8alkyl or the C that contains optional at least one atom replacement in O, S and N
1-C
8alkyl;
The quality proportioning that described modification connection alkene ether compounds accounts for total comonomer is for being greater than 0~10%, and, in vinylidene fluoride copolymers, the content of modification connection alkene ether compounds is greater than 0, but is less than or equal to 10% simultaneously.
As preferred mode, above-mentioned
1, R
2, R
3and R
4independently selected from hydrogen atom, fluorine atom, C
1-C
4the C that alkyl, at least one hydrogen atom are replaced by fluorine
1-C
4alkyl or the C that contains the replacement of O atom
1-C
4alkyl; More preferably, R
1, R
2, R
3and R
4independently selected from hydrogen atom or methyl.
As preferred mode, the quality proportion optimization that above-mentioned modification connection alkene ether compounds accounts for total comonomer is 0.1~2%.
Vinylidene fluoride copolymers provided by the invention, can also further contain the 3rd comonomer, described the 3rd comonomer be selected from vinyl fluoride, trifluoro-ethylene, tetrafluoroethylene, trifluorochloroethylene, tetrafluoroethylene, tetrafluoeopropene, five fluorine propylene, R 1216, perfluoro methyl vinyl ether, perfluoro propyl vinyl ether and other can with the Fluorine containing olefine of vinylidene copolymerization in a kind of, more than two or three combination, the quality proportioning that described the 3rd comonomer accounts for total comonomer is 0.1~50%.
Vinylidene fluoride copolymers of the present invention, performance perameter is preferably: weight-average molecular weight is 20~1,500,000 grams/mol, and molecular weight distribution coefficient is 1.6~5, and molecular weight distribution curve is unimodal distribution, melt flow rate (MFR) is 0.02~20 gram/10 minutes, and limiting viscosity is 0.5~5.0 * 10
2dl/g, fusing point is greater than 160 ℃, stands to be less than the weightlessness of 1%wt at the temperature higher than 400 ℃.
Vinylidene fluoride copolymers of the present invention, is preferably existence in vinylidene fluoride copolymers and can proceeds the two keys that react.
Be applicable to polymerization process of the present invention without particular limitation, in a better example of the present invention, described polymerization process is selected from letex polymerization, suspension polymerization and solution polymerization, more preferably letex polymerization and suspension polymerization.
The reaction pressure that is applicable to the inventive method in whole operating process remains on a value that is greater than vinylidene fluoride monomers emergent pressure generally.For used organic initiators, polyreaction of the present invention can adopt the polymerization temperature of the relative broad range that is greater than vinylidene fluoride monomers critical temperature.
A method for the novel vinylidene fluoride copolymers of high viscosity self-crosslinking is prepared in letex polymerization, comprises the following steps:
(1) to reactor, provide dispersion and the vinylidene fluoride monomers of the described connection alkene ether compounds monomer of at least one said structure formula (I) of part in water;
(2) to reactor, add emulsifying agent, chain-transfer agent and initiator, initiated polymerization under 70 ℃~120 ℃ temperature and 2.0~5.0MPa pressure;
(3) mode that adopts segmentation to feed intake adds dispersion and the vinylidene fluoride monomers of remaining at least one alkene ether compounds monomer claimed in claim 1 in water, and control polymerization pressure is 3.0~5.0MPa, and adds initiator;
(4), when polymerization pressure drops to 2.0~3.0MPa, stop adding initiator, until reaction finishes;
In reaction process, the quality proportioning that the connection alkene ether compounds monomer total amount that control adds accounts for total comonomer is for being greater than 0~10%.
A method for the novel vinylidene fluoride copolymers of high viscosity self-crosslinking is prepared in suspension polymerization, comprises the following steps:
(1) to reactor, provide dispersion and the vinylidene fluoride monomers of the described connection alkene ether compounds monomer of at least one said structure formula (I) of part in water;
(2) add dispersion agent, chain-transfer agent and initiator, initiated polymerization under the condition of 20 ℃~60 ℃ temperature and 3.0~12.0MPa pressure;
(3) mode that adopts segmentation to feed intake adds dispersion and the vinylidene fluoride monomers of remaining at least one alkene ether compounds monomer claimed in claim 1 in water, and control polymerization pressure is 3.0~5.0MPa.
(4) when polymerization pressure drops to 2.0~4.0MPa, stopped reaction;
In reaction process, the quality proportioning that the connection alkene ether compounds monomer total amount that control adds accounts for total comonomer is for being greater than 0~10%.
A method for the novel vinylidene fluoride copolymers of high viscosity self-crosslinking is prepared in solution polymerization, comprises the following steps:
(1) to reactor, provide dichloromethane solvent, part vinylidene fluoride monomers and at least one said structure formula (I) described connection alkene ether compounds monomer dichloromethane solution;
(2) add chain-transfer agent and initiator, initiated polymerization under the condition of 20 ℃~60 ℃ temperature and 3.0~12.0MPa pressure;
(3) mode that adopts segmentation to feed intake adds remaining vinylidene fluoride monomers and at least one alkene ether compounds monomer dichloromethane solution claimed in claim 1, and control polymerization pressure is 3.0~5.0MPa.
(4) when polymerization pressure drops to 2.0~4.0MPa, stopped reaction;
In reaction process, the quality proportioning that the connection alkene ether compounds monomer total amount that control adds accounts for total comonomer is for being greater than 0~10%.
As preferred mode, in above-mentioned three kinds of polymerization processs, the vinylidene fluoride monomers amount adding in described step (1) accounts for 1~25% of total vinylidene fluoride monomers add-on.
In order to improve the dispersiveness of monomer in water, optionally to dispersion system, add dispersion agent.The add-on of dispersion agent is without particular limitation, mainly can improve the dispersed of monomer and can not produce adverse influence to polyreaction subsequently or the polymkeric substance of formation.The type of same dispersion agent is also without particular limitation, as long as it can improve the dispersed of monomer and can not have a negative impact to polyreaction subsequently or the polymkeric substance of formation.In a good example of the present invention, described dispersion agent generally adopts fluorochemical surfactant or Mierocrystalline cellulose, and its indefiniteness example has: XC
nf
2ncOOM, wherein X is fluorine atom or hydrogen atom, and n is the integer of 4-12, and M is hydrogen atom or alkalimetal ion or ammonium ion or substituted ammonium ion or polyether segment, as C
7f
15cOOH.In a better example of the present invention, by 100 weight parts monomers raw materials, dispersion agent add-on is 0.01-1 weight part.
When adopting emulsion polymerization way, in order to improve the stability of monomer dispersion liquid, also optionally in dispersion liquid, add stablizer.In a better example of the present invention, use paraffin as the stablizer of dispersion liquid.The add-on of stablizer is without particular limitation, mainly can stable dispersions.While adopting suspension polymerization mode without adding stablizer.
The organic initiators that is applicable to the inventive method is without particular limitation, and it can be the conventional polymerization starter in this area.Described initiator is generally organo-peroxide, and its example comprises: di-isopropyl peroxydicarbonate, peroxy dicarbonate diisobutyl ester, peroxy dicarbonate diethyl ester.By 100 weight part vinylidene fluoride monomers or copolymerization mix monomer, for the consumption (being the add-on of step (2) initiator) of the initiator of initial initiated polymerization, can be 0.05-0.5 weight part.
While adopting emulsion polymerization way, except step (2) adds part initiator, in reaction process, need further to add organic initiators.In the methods of the invention, the object of the organic initiators adding is subsequently to control to generate the instantaneous molecular weight of polymkeric substance and final molecular weight distribution, therefore need to control the variation of organic initiators concentration in reaction system.The method of controlling organic initiators change in concentration in reaction system is at the decomposition rate under specified temp, by certain time interval, to add initiator according to initiator.Disposablely while adopting suspension polymerization mode add all initiators to reactor.
The chain-transfer agent that is applicable to the inventive method can be any compound that can continue vinylidene polyreaction, and the example of its explanation comprises: alcohols, as Virahol, propyl carbinol; Ketone, as acetone, butanone; Ester class, as ethyl acetate, diethyl carbonate, methylcarbonate; Containing halohydrocarbon, as chloroform, methylene dichloride; Aliphatics alkane, as normal hexane.By 100 weight part vinylidenes or copolymerization mix monomer, the consumption of chain-transfer agent is 0.01-0.2 weight part.
While adopting emulsion polymerization way, the monomer feed mode that is applicable to the inventive method is that VDF monomer and polar monomer segmentation join in polymerization reaction kettle, when still internal pressure is less than 4.0MPa, add VDF monomer enter in to specified pressure, when VDF monomer add-on is added to polar monomer dispersion wherein by pressure measurement pump during to certain value at intervals, until polyreaction finishes; While adopting suspension polymerization mode, the monomer feed mode that is applicable to the inventive method is similarly the segmentation of VDF monomer and is added to reactor, polar monomer after VDF monomer adds, still internal pressure is while being less than 4.0MPa, at intervals polar monomer dispersion joined to reactor by pressure measurement pump.
The novel vinylidene fluoride copolymers of high viscosity self-crosslinking of the present invention, its cohesive strength is greater than 50N/m, is suitable as lithium ion battery binding agent.
The present invention also provides a kind of composition that forms electrode, comprises the novel vinylidene fluoride copolymers of high viscosity self-crosslinking, powder electrode material and gives the additive of electrical conductivity.As preferred mode, each composition forms by following quality proportioning:
(1) vinylidene fluoride copolymers 1%~10%;
(2) as the carbon black that gives the additive of electrical conductivity, 2%~10%;
(3) powder electrode material 80%~97%, for by general formula LiMY
2the complex metal compound of representative, wherein M is selected from a kind of, more than two or three combination in Co, Ni, Fe, Mn, Cr and V, and Y is O or S.
Vinylidene fluoride copolymers of the present invention, after being prepared into the composition of electrode, two keys that can cause in the vinylidene fluoride copolymers in the composition of electrode by ultraviolet lamp carry out radical crosslinking, form crosslinking structure.
The composition of formation electrode of the present invention, is suitable as the electrode of lithium cell or electrical condenser.
Vinylidene fluoride copolymers of the present invention can be dissolved in the solvent of conventional polyvinylidene difluoride (PVDF) completely, and the example of described solvent has
n,
n-dimethyl pyrrolidone (NMP), N,N-DIMETHYLACETAMIDE (DMAc),
n,
n-dimethyl formamide (DMF) etc., preferably NMP.
By ISO4624 standard (adhesive power pull-off test), measuring polymkeric substance preparation becomes the cohesive strength after electrode, under 25 ℃ and 50% relative humidity, carries out.
Press GB/T 3682-2000 standard test melt flow rate (MFR) (MFR).Probe temperature is 230 ℃, and loading is 5 kilograms.
By ISO11358 standard, sample is carried out to TGA analysis.Under nitrogen atmosphere, under dynamic mode, carry out, record is respectively 0.5%, 0.75% and the required temperature of weightlessness of the polymkeric substance of 1%wt to obtaining, and these temperature are higher, and the thermostability of polymkeric substance is higher.
Press ASTM D4591 standard test melting enthalpy.Heating schedule is: with the heat-up rates of 10 ℃/min, by 80 ℃, be warming up to 190 ℃, 190 ℃ of insulations 10 minutes, with the cooling rates of 80 ℃/min, by 190 ℃, be cooled to 80 ℃, in 80 ℃, be incubated 2 minutes, with the heat-up rates of 10 ℃/min, by 80 ℃, be warming up to 190 ℃.DSC spectrogram while recording melting for the second time.
Embodiment
Below in conjunction with specific embodiment, the present invention is further described, but does not limit the invention to these embodiments.One skilled in the art would recognize that the present invention contained all alternativess, improvement project and the equivalents that within the scope of claims, may comprise.
embodiment 1
In 5 liters of vertical polymerization reaction kettles, adding in 2500 grams of deionized waters, 5 grams of ammonium perfluorocaprylates and homology mixture and 1 gram of melting range is the paraffin of 60 ℃ of left and right.Merge reactor, vacuumize and use nitrogen replacement, until oxygen level is less than 10ppm in reactor, then add a certain amount of vinylidene fluoride monomers to make still internal pressure to 2.0MPa.Then start to stir with the speed of 500rpm, reactor temperature is risen to 85 ℃, continue to supplement vinylidene fluoride monomers to reacting kettle inner pressure and reach 4.5MPa.Add 0.5 gram of di-isopropyl peroxydicarbonate (IPP), start polyreaction.By adding vinylidene fluoride monomers, make reacting kettle inner pressure maintain 4.5MPa, with the speed of 0.1 gram/15 minutes, add IPP, when the vinylidene fluoride monomers of specified wt part adds in complete and still reaction pressure to be down to 3.0MPa, stop adding IPP when following; Polar monomer connection thiazolinyl methyl ether feeds intake in 1% ratio of vinylidene weight part, vinylidene fluoride monomers feed intake weight reach preset value 50%, 60%, 70%, 80% time average segmentation join polymeric kettle.
By ISO4624 standard (adhesive power pull-off test), measure polymkeric substance preparation and become the cohesive strength after electrode.The preparation process of electrode is as described below: under room temperature state, under mechanical stirring, the resin of producing in 1g example 1 is dissolved in the NMP of 50g.Under the state stirring, add 2g graphitized carbon black and 30g cobalt acid lithium (LiCoO
2), fully mix and guarantee homogeneity.Then mixture is degassed and spread on aluminium foil with scraper under vacuum, finally the aluminium foil of sprawling upper electrode material mixture is positioned over vacuum drying oven be warming up to 60 ℃ dry 12 hours, finally prepare electrode slice.Use puller system survey meter to measure the cohesive strength of electrode slice upper electrode material.Each value is at least got the mensuration mean value of 5 electrode slices, and data are summarised in table 1.
embodiment 2
In 5 liters of vertical polymerization reaction kettles, adding in 2500 grams of deionized waters, 5 grams of ammonium perfluorocaprylates and homology mixture and 1 gram of melting range is the paraffin of 60 ℃ of left and right.Merge reactor, vacuumize and use nitrogen replacement, until oxygen level is less than 10ppm in reactor, then add a certain amount of vinylidene fluoride monomers to make still internal pressure to 2.0MPa.Then start to stir with the speed of 500rpm, reactor temperature is risen to 85 ℃, continue to supplement vinylidene fluoride monomers to reacting kettle inner pressure and reach 4.5MPa.Add 0.5 gram of di-isopropyl peroxydicarbonate (IPP), start polyreaction.By adding vinylidene fluoride monomers, make reacting kettle inner pressure maintain 4.5MPa, with the speed of 0.1 gram/15 minutes, add IPP, when the vinylidene fluoride monomers of specified wt part adds in complete and still reaction pressure to be down to 3.0MPa, stop adding IPP when following; Polar monomer connection thiazolinyl methyl ether feeds intake in 10% ratio of vinylidene weight part, vinylidene fluoride monomers feed intake weight reach preset value 50%, 60%, 70%, 80% time average segmentation join polymeric kettle.
Use 1 gram of multipolymer to prepare electrode slice.Cohesive strength is measured and is summarised in table 1.
embodiment 3
In 5 liters of vertical polymerization reaction kettles, add 2500 grams of deionized waters, 5 grams of methylcellulose gum.Merge reactor, vacuumize and use nitrogen replacement, until oxygen level is less than 10ppm in reactor, add the vinylidene fluoride monomers of specified amount, then add the polar monomer of specified amount to join thiazolinyl methyl ether in the segmentation that feeds intake of 1% ratio of vinylidene weight part.Then start to stir with the speed of 500rpm, reactor temperature is risen to 40 ℃, add 2.5 grams of di-isopropyl peroxydicarbonates (IPP), start polyreaction.Question response stops polyreaction during to the fixed time.
Use 1 gram of multipolymer to prepare electrode slice.Cohesive strength is measured and is summarised in table 1.
embodiment 4
In 5 liters of vertical polymerization reaction kettles, add 2500 grams of deionized waters, 5 grams of methylcellulose gum.Merge reactor, vacuumize and use nitrogen replacement, until oxygen level is less than 10ppm in reactor, add the vinylidene fluoride monomers of specified amount, then add the polar monomer of specified amount to join thiazolinyl propyl carbinol ether in the segmentation that feeds intake of 1% ratio of vinylidene weight part.Then start to stir with the speed of 500rpm, reactor temperature is risen to 40 ℃, add 2.5 grams of di-isopropyl peroxydicarbonates (IPP), start polyreaction.Question response stops polyreaction during to the fixed time.
Use 1 gram of multipolymer to prepare electrode slice.Cohesive strength is measured and is summarised in table 1.
embodiment 5
In 5 liters of vertical polymerization reaction kettles, add 2500 grams of deionized waters, 5 grams of methylcellulose gum.Merge reactor, vacuumize and use nitrogen replacement, until oxygen level is less than 10ppm in reactor, add the vinylidene fluoride monomers of specified amount, then add the polar monomer of specified amount to join thiazolinyl octyl ether in the segmentation that feeds intake of 1% ratio of vinylidene weight part.Then start to stir with the speed of 500rpm, reactor temperature is risen to 40 ℃, add 3 grams of di-isopropyl peroxydicarbonates (IPP), start polyreaction.Question response stops polyreaction during to the fixed time.
Use 1 gram of multipolymer to prepare electrode slice.Cohesive strength is measured and is summarised in table 1.
embodiment 6
Use and press the prepared electrode slice of embodiment 1, in argon shield atmosphere, utilize the ultraviolet light that wavelength is 365nm to irradiate, after 12 hours, take out electrode slice.Use puller system survey meter to measure the cohesive strength of electrode slice upper electrode material, data are summarised in table 1.
embodiment 7
Use and press the prepared electrode slice of embodiment 2, in argon shield atmosphere, utilize the ultraviolet light that wavelength is 365nm to irradiate, after 12 hours, take out electrode slice.Use puller system survey meter to measure the cohesive strength of electrode slice upper electrode material, data are summarised in table 1.
embodiment 8
Use and press the prepared electrode slice of embodiment 3, in argon shield atmosphere, utilize the ultraviolet light that wavelength is 365nm to irradiate, after 12 hours, take out electrode slice.Use puller system survey meter to measure the cohesive strength of electrode slice upper electrode material, data are summarised in table 1.
embodiment 9
Use and press the prepared electrode slice of embodiment 4, in argon shield atmosphere, utilize the ultraviolet light that wavelength is 365nm to irradiate, after 12 hours, take out electrode slice.Use puller system survey meter to measure the cohesive strength of electrode slice upper electrode material, data are summarised in table 1.
embodiment 10
Use and press the prepared electrode slice of embodiment 4, in argon shield atmosphere, utilize the ultraviolet light that wavelength is 365nm to irradiate, after 12 hours, take out electrode slice.Use puller system survey meter to measure the cohesive strength of electrode slice upper electrode material, data are summarised in table 1.
comparative example 11
KUREHA 9200 vinylidene fluoride copolymers that the limiting viscosity of using 1 gram is 1.8dl/g are prepared electrode slice.Cohesive strength is measured and is summarised in table 1.
comparative example 12
SOLVAY 5130 vinylidene fluoride copolymers that the limiting viscosity of using 1 gram is 2.3dl/g are prepared electrode slice.Cohesive strength is measured and is summarised in table 1.
Table 1
Embodiment |
Comonomer |
Limiting viscosity |
Melting index (g, 230 ° of C, 5kg/10min) |
Fusing point (° C) |
Cohesive strength (N/m) |
Thermal weight loss (400 ℃) |
Solution appearance |
Embodiment 1 |
Connection thiazolinyl methyl ether (letex polymerization, 1%) |
1.4 |
0.47 |
170 |
103 |
<1% |
Clear |
Embodiment 2 |
Connection thiazolinyl methyl ether (letex polymerization, 10%) |
0.9 |
5.12 |
165 |
73 |
<1% |
Clear |
Embodiment 3 |
Connection thiazolinyl methyl ether (suspension polymerization, 1%) |
2.1 |
0.23 |
172 |
110 |
<1% |
Clear |
Embodiment 4 |
Connection thiazolinyl propyl carbinol ether (suspension polymerization, 1%) |
1.2 |
1.09 |
168 |
78 |
<1% |
Clear |
Embodiment 5 |
Connection thiazolinyl octyl ether (suspension polymerization, 1%) |
1.0 |
3.10 |
166 |
63 |
<1% |
Clear |
Embodiment 6 |
Sample 1 is through uv irradiating |
- |
- |
- |
379 |
- |
- |
Embodiment 7 |
Sample 2 is through uv irradiating |
- |
- |
- |
134 |
- |
- |
Embodiment 8 |
Sample 3 is through uv irradiating |
- |
- |
- |
412 |
- |
- |
Embodiment 9 |
Sample 4 is through uv irradiating |
- |
- |
- |
268 |
- |
- |
Embodiment 10 |
Sample 5 is through uv irradiating |
- |
- |
- |
144 |
- |
- |
Comparative example 11 |
n.a |
1.8 |
0.56 |
171 |
23 |
<1% |
Clear |
Comparative example 12 |
n.a. |
2.3 |
0.12 |
166 |
56 |
<1% |
Clear |
By the known VDF of result of above-mentioned table 1, by carrying out copolymerization with described polar monomer, can obtain adhesive property and have the PVDF multipolymer significantly improving, PVDF multipolymer and electro-conductive material preparation simultaneously becomes after electrode slice, by ultra violet lamp, can there is crosslinking reaction, further improve significantly it as the cohesive strength of lithium cell binding agent.