PDF Publication Title:
Text from PDF Page: 035
US 10,991,944B2 15 16 SynthesisandFabricationProcedures mogravimetricanalysis(TGA).Thermogravimetricanalysis FIG.1showsaschematicdiagramforthevapordeposi- wascariedoutinnitrogenfromroomtemperatureto60° tionofgammamonoclinicphasesulfuroncarbonnanofibers C.ataheatingrateof10°C./min.Theweightloadingofthe (CNFs).TheCNFsarefabricatedusingstandardmethods. cathodeswasabout50%with0.6-0.7mgofgammamono TheCNFsarethenholepunched(diameter1mm)and 5 clinicphasesulfur(FIG.4B). placedinthevapordepositionasembly. ElectrochemicalCharacterization Thevapordepositionassemblyconsistsofastainlesstel Electrochemicalcharacterizationwas cariedoutwith autoclaveasshowninFIG.2.Othermaterialscommonly gammamonoclinicphasesulfurvapordepositedonCNFsas usedforautoclavesmaybeemployedaswel,forexample, apositiveelectrode,alithiumdisk(diameter13mm)asa aluminumautoclaves.Typicaly,theautoclaveconsistsofa10negativeelectrode,acelgardseparatoranda30microliter toppartorautoclavelidandbotompartthatdefinesan electrolyte(1MLIPF.inethylenecarbonate:diethylenecar autoclavechamber.Thetoppartformsalidthatcoversthe bonate1:1v/v)inaCR2032coincel.Thepositiveelectrode chamberofthebotompart.Thechamberofthebotompart wasfre-standing,hadabouta50%weightloadingof consistsofasulfurreservoirzoneandsievezone.Thesulfur gammamonoclinicphasesulfurandanabsoluteamountof reservoirzoneofthisparticularaparatusisloadedwith15gammamonoclinicphasesulfurofabout0.6-0.7mg.To about10.8-1gramsofsulfur(Sigma-Aldrich)inanalumi- analyzetheelectrochemicalperformance,charge-discharge numboat.Thesieveisthenplacedsuchthatbublesofhot testswereperformedataslowC/50ratetobeabletodetect meltedsulfurdonotcontacttheeighttotencathodesthatare evidenceofsidereactions. placedonthesieve,i.e.adistanceofabout5cm is Fre-standingcarbonnanofibers-basedelectrodesare maintainedbetwenthetopmostpartofa20mLaluminum20definedaselectrodeswithoutbinderandconductiveadi crinkledishfromVWR,andthesieve.AnO-ringisusedto tiveswhichmaybeheldandusedindependentlyofa sealtheautoclavetopreventescapeofsulfurvapor.After metaliccurentcolector.Thesearestandaloneelectrodes heatingtheautoclavefor25hoursinanovenataspecified sincetheyhaveelectronchanelsoriginatingfromcarbon temperatureof,forexample,175°C.,theautoclavewas nanofibersandmaynotneedanaditionalmetalicshetfor coledtoambienttemperatureofabout18-25oC.inan25mechanicalstabilityandelectricalconductivity.Depending ambientairenvironment.Itisbelievedthatsuddenremoval onspecificdevicerequirements,onemayneedtousea oftheautoclavefrom175°C.toambientatmosphereresults curentcolectorshet. inahigh-temperaturegradientthatfacilitatestheformation FIG.5AshowsinitialdischargeandchargecurvesatC/50 ofgammamonoclinicphase. withacapacityofabout170mAh/gand169mAh/g.The MaterialCharacterization 30curvesalsodisplayasingleplateauconversionwithno SEMimagesshowaconformalcoatingofthegamma evidenceofsidereactions. monoclinicphasesulfuronthecarbonnanofibers,inadi- FIG.5Bshowscharge-dischargecurvesathighercurent tiontolargechunksofthegammamonoclinicphasesulfur rates,C/10,C/5andC/2.Thecorespondingdischarge locatedintheinterfiberspacing.Thephaseofthesynthe- capacitiesare10,1000and920mAh/g,mrespectively. sizedmaterialwascharacterizedusingX-raydifraction;the35Thiselectrodedemonstratesstableoperationalperformance, peaksmatchwelwiththegammamonoclinicphasesulfur, exhibitingarelativelyconstantcapacityover130cycles. acordingtotheJointCommitteeonPowderDifraction FIG.5Cshowsstablecharge-dischargecurvesatacurent Standards(JCPDS)Database.Thegammamonoclinicphase rateofC/2forvariousnumbersofcycles. sulfurdepositedcarboncathodeswereemployedincarbon- ThecyclicvoltammogramofFIG.5D,conductedata ate-basedelectrolytes(1MLiPF6inEC:DEC(1:1v/v)and40scanrateof0.05mV/s,showsasinglestableplateauduring showedasingleplateaudischarge-chargebehaviorwithan boththeoxidationandreductioncyclescorespondingtothe exceptionalcapacityof80mAh/gafter10cyclesataC/2 charge-dischargecurves. cyclingratewithhighcoulombiceficiency.Thecurent FIG.5Edisplaystherateperformanceofgammamono loadingis0.5-0.7mgofgammamonoclinicphasesulfur, clinicphasesulfurvapordepositedontheCNFstoforma with30% higherweightloadingsofgammamonoclinic45cathode.Thecathoderetainedcapacitiesofabout80 phasesulfurbeingposible.Inadition,thesecathodesare mAh/gatarateofC/20,70mAh/gatarateofC/10,750 usedwithoutaditionalbinders/curentcolectorsfurther mAh/gatarateofC/5and600mAh/gatarateofC/2for eliminatingdeadweightinthebatery.Useofthegamma 30cycleseach.Furtherdecreasingthecurentdensityto monoclinicphaseofsulfurwithanon-confinement-based C/10,acapacityof700mAh/gcouldbeachieved,demon aproachenablestheuseofasolidstatereactionwithoutthe50stratingtheexceptionalratecapabilityoftheelectrode. needforcomplexandexpensiveconfiningarchitecturesand TheLi Sbaterydemonstratedultra-stableandlong-life bypasespolysulfideformation,enablingthebateryto cyclingperformancefor130cyclesatacurentrateofC/2 achieveahighcapacitywithanextendedcyclelife. withacapacityofabout70mAh/g.Thisremarkable Amorphologicalanalysisofthevapordepositedsulfuron stabilitycanbeatributedtothesolidtosolidconversionof theCNFswasconductedusingscaningelectronmicros-5gammamonoclinicphasesulfurtoLi,S,therebyeliminating copy(SEM).TheSEMimages(FIGS.3A-3D)showthatthe formationofpolysulfides.Theexcelentperformanceof sulfurisdepositedconformalyontheexteriorsurfacesof thesegammamonoclinicphasesulfurelectrodesdemon CNFs,andthatblocksofsulfuraredepositedinbetwenthe stratesthefeasibilityofhigh-energycarbonate-basedLiS celsforpracticalaplication. material,X-raydifractionwasemployed.TheX-raydif-60 ItisconsideredthatLi–Sbateries,aswelasothersulfur fractionpeaksofthevapordepositedsulfurmatchedthe bateries,canbemadewithgammamonoclinicphasesulfur paternofgammamonoclinicphaseofsulfur(JCPDSfile loadingsoncarbonnanofibersoffrom3-6mg/cm2,orfrom fromtheInternationalCenterforDifractionData)(FIG. 4-5mg/cm2 4A).X-raydifractionalsoconfirmedthatthedeposited Fre-standingcarbonnanofiber/Scathodeswerealso sulfurwasacrystalinematerialthatalowsforuseofthe65testedforlong-termcyclinginroomtemperatureNa S sulfurintheLi-Sbaterywithoutconfinement.Weight bateries.Theas-preparedCNF/S(~1.08mg/cm2,43.8wt% loadingofthesulfurontheCNFswascalculatedbyther- S)cathodeswereuseddirectlyascathodesin2032type fibersintheinter-porearea.ToanalyzeandquantifythePDF Image | SYNTHESIS OF GAMMA MONOCLINIC SULFUR
PDF Search Title:
SYNTHESIS OF GAMMA MONOCLINIC SULFUROriginal File Name Searched:
US10991944.pdfDIY PDF Search: Google It | Yahoo | Bing
Sulfur Deposition on Carbon Nanofibers using Supercritical CO2 Sulfur Deposition on Carbon Nanofibers using Supercritical CO2. Gamma sulfur also known as mother of pearl sulfur and nacreous sulfur... More Info
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |