聚偏氟乙烯丙烯酸酯凝膠聚合物電解質的制備及性能研究

聚偏氟乙烯丙烯酸酯凝膠聚合物電解質的制備及性能研究

lywelle-pgening相關程序dye-sensiedsoltan（sds）是一個用簡單模糊的線描技術為基礎的系統(tǒng)，并以高光刻過渡技術為基礎。sdecs有一個相對較高的整體，它是由11.04%的?？傊?，它是一個輕松的紡織工具和一個長而結實的政黨。Tosolvetheseproblems,alternativerobustsealingmethods,replacementofthevolatilesolventswithionicliquid,organicandinorganichole-transportmaterials,nano-composites,solid,andquasi-solidstatepolymerelectrolyteshavebeenattempted.Gelpolymerelectrolytes(GPEs)areconstructedbytrappingliquidelectrolytes,whichusuallycontainorganicsolvents(PC,ECorCAN)andinorganicsalts,suchasLiI,NaIandKI.GPEspossesslowvaporpressure,excellentcontactingandfillingpropertiesbetweennanostructuredelectrodeandcounterelectrode,higherionicconductivitycomparedwiththeconventionalpolymerelectrolytesandexcellentthermalstability.Therefore,GPEshaveattractedintensiveattentionsandfoundtheirwideapplicationinDSSCs[11,12,13,14,15,16].Itisknownthatpoly(vinylidenefluoride)(PVDF)isphotochemicallystableeveninthepresenceofTiO2andPtnanoparticlesandacrylatehasgoodsolventretention.In2001,Rajendran,etalreportedanelectrochemicalinvestigationonpoly(methylmethacrylate)(PMMA)/PVDFblend-basedpolymerelectrolytesfortheapplicationsinlithiumbatteries.Thehigherconductivitieswereobservedinthepolymermembranesresultfromthelowerdegreeofcrystallinity.OurteaminvestigatestheperformanceofDSSCsemployingaquasi-solidpolymerelectrolytesbasedonPVDF-PMMAblendpolymer.Interpenetratingpolymernetwork(IPN)isaspecialkindofpolymerblend.Itcanbedefinedasacombinationoftwopolymersinnetworkform,oneofwhichissynthesizedand/orcross-linkedintheimmediatepresenceoftheother.Itcanbedistinguishedfromblendpolymerintwoways:(1)IPNswells,butdoesnotdissolveinsolvents;(2)CreepandflowaresuppressedinIPN.IPNmaybemadefrompolymer(1),whichcanholdliquidelectrolyteandexhibithighionicconductivity,andpolymer(2),whichismechanicallyandelectrochemicallystabletoelectrodes.TCWei,etalpreparedacross-linkingfilmofPVDF-HFP/PEG/PEGDMAelectrolytewithexcellentmechanicalstrengthevenat10μmthickness.DSSCequippedwiththispolymerelectrolyteshowsaconversionefficiencyover4%under100mW/cm2illumination.Toourknowledge,therearenottoomanyreportsaboutpolymerelectrolytebasedonPVDF/acrylateblendorIPNappliedinDSSCs.Inthispaper,amicro-phaseseparationtypeGPEbasedonIPNsofcross-linkedacrylateissynthesized.Thisisaspecialkindofpolymerelectrolyte,whichliesbetweenthechemicallycross-linkinggelledpolymerelectrolyteandtheporouspolymerelectrolyte.Theycanswellwithmoreliquidelectrolytesolutionthantheordinaryporoussolid-stateelectrolytebecauseofthestronginteractionofelectrolytesolutionandoneoftheinterpenetratingcomponents.Inthepaper,polymermembraneispreparedwithmoreporesbythephaseinversionprocessandtheirswellinganddiffusioncharacteristicsarestudiedbychangingpolymercompositionordifferentcross-linkingmonomers.Moreover,thedifferencesbetweenblendpolymernetwork(BPN)andIPNarestudied,thusprovidinghelpfulreferenceinselectinganddesigningofpolymerelectrolyteforDSSCs.1EXPERIMENT1.1產品稅政策1.1.1通過轉色體的ames方法,表達雙側左面,n-dimethyf-am研磨dmf/雙dmfam研磨-非織造材料pvdf/anamoperationseminedThedryporouspolymermembranecomposedofPVDF(SOLEF1015)andPMMA(Mw=200000)issynthesizedbythephaseinversionprocess.ThedriedpolymerpowdersofPVDFandPMMAaredissolvedinN,N-dimethylformamide(DMF).Anamountofpropanetriolasnonsolventisthenaddedundercontinuousstirringat60°Cfor12htoformhomogeneoushybrid.Theresultingviscousmixturespreadonaglasssubstrateisheatedto80°Cfor24htoremovesolventandnonsolvent.1.1.2雙標準最優(yōu)—IPNsPVDF/PMMA(Ⅱ)orPVDF/PEGDMA(Ⅲ)ThedriedpolymerpowdersofPVDFandpropanetriolaredissolvedinDMF.Theacrylatemonmers,methylmethacrylate(MMA)orethyleneglycoldimethacrylate(EGDMA,Aldrich),arethenaddedintothegelsolutionundercontinuousstirringat50°Ctoformhomogeneoushybrid.Finally,asmallamountofinitiator,2,2′-azobisisobutyronitrile(AIBN)isaddedinthesolution.Theresultingviscousmixturespreadingonaglasssubstrateisheatedto80°Cfor24htoensurepolymerizationofacrylatemonmersandtocompletephaseinversionprocess.Inthesefilmspreparation,theweightratiosofPVDF/acrylatepolymermixturesare8/2,7/3,6/4,and5/5,respectively.Thethicknessofthepolymerelectrolytemembranesisapproximately100μm.Theformedfilmiswashedinethanoltoextractresidualpropanetriol.Finally,thedriedpolymermembranesaresoakedinliquidelectrolyte(0.5mol/LNaI,0.05mol/LI2,0.1moL/L4-tert-butylpyrdineinthebinaryorganicsolventmixturepropylenecarbonateandethylenecarbonatewith4∶6(inweight))for12htoobtainthedesiredGPEs.1.2非so階段—PreparationofTiO2photoanodeSelf-alignedhighlyorderedTiO2nanotubearraysarefabricatedbypotentiostaticanodicoxidationinatwo-electrodeelectrochemicalcell.Theseparationdistancebetweentheelectrodesis4cm.ThevoltageappliedbetweenTi-foilanodeandPtcathodeis20Vattheroomtemperature.TheusedelectrolyteisethyleneglycolsolutionwithanadditionofH2O(1%involume)andNH4F(0.25%inweight).Allsolutionsarepreparedfromreagentgradechemicals.Priortoanodization,alltheTi-foilsamplesarecleanedwithacetoneandethanol,chemicallypolishedtoamirrorimagebythepolishingsolution,andthenrinsedwithdistilledwateranddriedinnitrogenstream.OnlyonefaceoftheTi-foilisexposedtotheelectrolyteduringanodizationbytape-maskingtheotherface.TiO2nanotubearrayshavinglengthsupto20μmaregrowninverticaldirectiontotheunderlyingTi-foilwithanexposedareaof0.25cm2.Theas-preparednanotubeTi-foilisthoroughlywashedwithdistilledwater.Thentheyarecrystallizedintoanatasephaseafterannealingat450°Cfor3hinoxygenatmospherebecauseas-anodizedTiO2nanotubesareamorphousphase.1.3as研磨b.aglit.asgeethauchingasi-solid-sizedsi-solid-si4el明最.....3.3日assemping.el長期purchasedel長期purchased-..................................................TheTiO2filmisimmergedina0.5mmolethanolsolutionofcis-[(dcbH2)2Ru(SCN)2](N719;Solalonix)for24htoabsorbthedyeadequately,andtheotherimpuritiesarewashedupwithanhydrousethanolanddriedinmoisture-freeair.Afterthat,adye-sensitizedTiO2filmisprepared.Aquasi-solid-stateDSSCisassembledbysandwichingasliceofGPEbetweenadyesensitizedTiO2electrodeandaplatinumcounterelectrode(purchasedfromDYSEOL).Thetwoelectrodesareclippedtogetherwithclamps.Forcomparison,DSSCwithconventionalliquidelectrolyteisalsoassembled.Theactiveareaofthecellis0.25cm2.1.4參數(shù)估計pheningTheIRabsorptionspectraaretakenusinganattenuatedtotalreflectionFouriertransforminfrared(FFIR)spectrometer(PerkinElmer1760)overtherangefrom600cm-1to4000cm-1.Themorphologyofpolymermembraneischaracterizedbyscanningelectronmicrograph(Quanta200,FEI).TheelectrolyteuptakeiscalculatedbyUptake=(Wi-W0)/W0×100%whereWiandW0aretheweightsofthewetanddrymembranes,respectively.Theporosityofmembranesismeasuredbyimmersingthemembranesinton-butanolfor1h.TheporosityiscalculatedusingthefollowingequationPorosity=(Mb/ρb)/[(Mp/ρp)+(Mb/ρb)]×100%whereMpistheweightofmembrane,Mbtheweightofabsorbedn-butanol,ρpthedensityofthemembraneandρbthedensityofn-butanol,respectively.ThesymmetriccellisbuilttocharacterizeelectrochemicalpropertiesofelectrolytewithasimilardesignasDSSCbysandwichingtheGPEsamplebetweentwoPtelectrodes(Pt/electrolyte/Pt).TheelectrolyteresistanceRbismeasuredusingCHI660electrochemicalworkstationinthefrequencyrangefrom10-2to105Hzwithamplitudeof5mV.TheionicconductivityoftheGPEiscalculatedwithσ=d/RbSwheredisthethicknessofelectrolyteandStheareaofelectrolyte.ToinvestigatethediffusioncoefficientsofI3-intheelectrolyte,steady-statevoltammogramsofGPEisperformed.Thesystemispolarizedfrom0Vto1Vatarateof10mV/s.Theapparentdiffusioncoefficientsoftriiodide(D)canbecalculatedaccordingtotheequationD=Ilimd/2nFCwhereIlimisthelimitingcurrentdensity,ntheelectronnumberpermolecule,dthethicknessofgelelectrolyte,FtheFaradayconstantandCthebulkconcentrationofelectroactivespecies.Photocurrent-voltagecharacteristicsofDSSCsareobtainedbyaKeithleymodel2400digitalsourcemeterusinganOriel91192solarsimulatorequippedwithAM1.5filterandintensityof100mW/cm2.Thefillfactorandtheconversionefficiency(η)ofthecellarecalculatedbythefollowingequationsff=Pmax/IscVoc=ImpVmp/IscVoc,η=ImpVmp/PinwhereIscistheshort-circuitcurrentdensity;Voctheopen-circuitvoltage;Pinistheincidentlightpower;ImpandVmparethecurrentdensityandvoltageinthephotocurrent-voltagecurves,respectively,atthepointofmaximumpoweroutput.2影響的神圣迪迪斯運營2.1通過轉色織物viractretchingponde-pegdatching清理劑,vcdf/me模擬kraftretchingveractityob環(huán)保c案例見表1ThechemicalcompositionsforthepreparedpolymermembranesareanalyzedusingFTIRspectroscopy(seeFig.1).ThecharacteristicpeaksofPVDFat838,877,1074,1172,1232and1406cm-1areobservedforallthesamples.Thesamplesshowthatsharplinesat1725,1148cm-1correspondtoC=OandC-O-Cstretchingvibrationbandsofacrylatepolymer.Nopeaksobservedat1640cm-1indicatethattheC=Cbondinuncross-linkedacrylatemonmerdisappearesviacross-linkingwhenthemembraneisprepared.FTIRspectraconfirmthatbothPVDFandPMMAorPEGDMAarepresentedinthepolymermembrane.2.2pvdf-pmmab掌握Fig.2showstypicalSEMimagesofthepolymermembraneswithdifferentsystems.Allmembranesdisplayasurfacewithahomogeneousporosity.Theinteriorofthemembranehasauniformporousstructureaswellastheexterior.Thisindicatesthatthecellularporesareallopenwithextensivepore-poreinterconnections.ForthePVDF-PMMAblendsystem,therearemanysmallnodularentitiesprotrudingoutoftheporewall,whicharemorelikelytobePMMAparticlesseparatingfromthepolymerhost.ThesizeandtheamountofthenodulartexturesincreasewiththeincreaseoftheamountofPMMA.Itcaninferthatsolid-soliddemixinghasoccurredinadditiontoliquid-liquiddemixingorcrystallizationphaseseparationprocess.Onthecontrary,noobviousnodulartexturesarefoundinbothPVDF-PMMAandPVDF-PEGDMAIPNmembranesowingtobettercompatibilitybetweenPVDFandinterpenetrationacryatepolymer.ThesizeandtheamountoftheporesdecreasewiththeincreaseoftheamountofacryatepolymerfortheIPNsystem.Itcanbeexplainedthatmorecross-linksresultindensernetworkstructure.2.3pvdf/acratioTheelectrolyteuptakeisfoundtodependontheporosityofthepolymermembranesinthepaper.AccordingtoSaito,etal,theporosity,oneoftheimportantparametersofporouspolymermembranes,candominatetheconductionpropertiesofthecarriers.Thus,n-butanolabsorptiontechniqueisusedtomeasuretheporosityofthepolymermembranes.InFig.3,themaximumoftheporosityisobservedwhentheweightratioofPVDF/acrylatepolymeris7/3forallsystems.Theseresultsindicatethatthesizeofthemacrovoidscanbecontrolledbyadjustingtheacrylatepolymercontent.ComparedwithPVDF/PMMABPNandPVDF/PEGDMAIPN,PVDF/PMMAIPNgivesadistinctdecreaseinporosity.PVDF/PMMAIPNshowsdensernetworkstructurethanothertwosystemsbecauseMMAhashigherreactivityandresultsinhighlyorderedandregularpatternednetworks.Thehighestporosityof45.7%ismeasuredinPVDF/PEGDMAIPN,whichisattributedtoaverylowandsmoothcrosslinkednetworkstructureofthemembrane.Thetendencyoftheelectrolyteuptakeissimilartothatofporosity(seeFig.4).GPEswith30%(inweight)PEGDMAand70%(inweight)PVDFhasthemaximumelectrolyteuptake261.1%.AccordingtoSaitoandco-workers,therearetwodistinctstepsforliquidelectrolyteuptakeinPVDF-basedporousgelpolymermembranes.Firstly,theliquidelectrolyteoccupiessomeporespacesofthemembrane.Then,thoseelectrolytesinporespenetrateandswellthepolymerchainstoformthegel.2.4pvdf/acrafting標準EISisusedtocharacterizetheelectrochemicalbehaviorofGPE.TheionicconductivityofGPEs(σ)andthetriiodideapparentdiffusioncoefficient(D)ofPVDF/PMMBPN,PVDF/PMMAIPNandPVDF/PEGDMAIPNaresummarized,respectivelyinTables1-3.Thepresenceofacrylatepolymercaninfluencetheconductivityindifferentways.Thecrystallinityofthemembraneisreducedwithincreasingofacrylatecontent,whichimprovestheconductivityofGPEs.Meanwhile,theporosityofthemembranedecreaseswithincreasingacrylatecontent,leadingtothedropoftheconductivityofGPEs.Asaresult,GPEshowsthehighestσandDwhentheweightratioofPVDF/acrylatepolymeris7/3andthendecreases.ThegreatestvaluesσandDobtainedinPVDF/PEGDMAIPNare3.02×10-4S·cm-1and1.10×10-6cm2·s-1.2.5相關領域的計算公式ThephotocurrentperformanceforDSSCwithdifferentelectrolytes(AtoD)aretested.Thephotocurrent-voltagecurvesareshowninFig.5andcellparameterscorrespondingtotheseDSSCsaresummarizedinTable4.Itisregrettablethattheconversionefficienciesofthecellsareunsatisfactory.Furtherimprovementsondeviceperformanceshouldbeachievablethroughoptimizationofelectrodepreparationandthecellassembling,etc.TheseresultsindicatethatIPNworsensthecellperformancetoacertainextentforitsdensernetworkstructure,comparedwithBPNcomposedofthesameconstituentinthesameproportions.SelectingEGDMAascrosslinkeroptimizesthephotovoltaicperformance.ThiscanbeexplainedonthebasisofporosityformationinthenetworkstructureofthegelandexcellentcompatibilitywithPVDF.TheresultaccordswithσandDvariationlaw.DSSCemployingPVDF/PEGDMAIPNGPEyieldsanope