PDF Publication Title:
Text from PDF Page: 023
23 Arbinelectrochemicalworkstationatascanningrateof1 mV/s.Inadition,theelectrochemicalperformancesofvari ouscelswerealsoevaluatedbygalvanostaticcharge/dis chargecyclingatacurentdensityof50mA/g.Forlong-term cyclingtests,multi-channelbaterytestersmanufacturedby LAND wereused. SomerepresentativedataarepresentedinFIG.9,which showstheRagoneplots(celpowerdensityvs.energyden sity)ofthreLi-ScelshavingaS-coatedgraphenebased cathodewithaScoatingthicknessof20nm,65nm,and125 nm,respectively.Clearly,thinestcoatingprovidesthehigh estenergydensityamongthethrecels.Thehighestachiev ablecelenergydensityofthecelcontainingthethinestS coatingSupportedongrapheneshetsisashighas802 Wh/kg,whichis4timesbeterthantheenergydensity(150 200Wh/kg)ofthebestlithium-ionbaterycelscurently availableonthemarket. 5 10 15 24 alexistingmaterials.Highstrengthimpartsgoodstruc turalintegritytotheresultingelectrode. (4)Ahighthermalconductivityimpliesahighheatdissipa tionrate.Thisisanimportantfeaturesincethechargeand dischargeoperationsofabateryproduceagreatamountof heat.Withoutafastheatdisipationrate,thebaterycannot bechargedordischargedatahighrate. (5)Themostcommonlyusedconductiveaditivesarecarbon black(CB)oracetyleneblack(AB),whicharenotvery electricalyconductive.Grapheneshetshaveanelectrical conductivity(upto20,000S/cm)thatisseveralordersof magnitudehigherthanthatofCBorAB(typicaly0.01-10 S/cm). (6)Grapheneshetsintheinteriorandtheexteriorsurfaceof a particulate provide not only a robust 3-D network of electron-conductingpathsandhighconductivity,butalso US9,203,084B2 Thesedatahaveclearlydemonstratedthesuperioradvan tagesofthepresentlyinventedcathodeactivematerial-coated grapheneshets.ThepresentlyinventedLi Sbateryfea turingaS-coatedgrapheneshetcathodecanbecharged/ dischargedfor1,000cycleswithoutsuferinga20%capacity decay.Thehighenergydensityimpliesthatacurentelectric vehiclewitharatingof300milesononebaterycharge(e.g.25 TeslaModel-SalbateryEV)canbeimprovedtoaratingof 1,200milesononecharge,giventhesamebateryweight. Thiswouldreducetheneedtobuildsomanychargingstations andwouldalsoreducedrivers“rangeanxiety',thetwofac torsthathavethusfarpreventedalEVsfrombeenwidely 30 acceptedbyconsumers.With1,200milespercycleandalife expectancy of approximately 1,000 cycles, the presently inventedLi SbaterywouldenableanEVtorunfor1,20, 000milesbeforeneedingabateryreplacement.Thisinven InSummary,thepresentlyinventedgraphene-enhanced particulatesSurprisinglyimpartthefollowinghighlydesir ableatributestoalithiumbateryelectrode:highreversible capacity,lowireversiblecapacity,hightapdensity,electrode fabricationease(shapeofsecondaryparticlestypicalybeing sphericalornearspherical),Smallprimaryparticlesizes(for high-ratecapacity),compatibilitywithcommonlyusedelec trolytes(embracinggrapheneshetshelptoisolateactive materialparticlesfromelectrolyte),andlongcharge-dis chargecyclelife. The invention claimed is: 1.A cathodeelectrodeofalithiumbatery,whereinsaid cathodeelectrodecomprisesacathodeactivematerial-coated grapheneshet,whereinsaidgrapheneshethastwoopposed paralelsurfacesandatleast50%areaofoneofsaidtwo Surfacesiscoatedwithacathodeactivematerialandwherein saidgraphenematerialisinanamountoffrom0.1%to99.5% byweightandsaidcathodeactivematerialisinanamountof atleast0.5%byweight,albasedonthetotalweightofsaid graphenematerialandsaidcathodeactivematerialcombined. (2)Thecathodeactivematerialcoatingcanbeverythin(1 nm-100nm),enablingfastelectronandlithiumiontrans port,yetstilprovidingahighactivematerialcontentand beingconducivetotheformationofelectrodeswitha desiredthicknes(100-250um).Further,eachandevery thinactivematerialcoating(e.g.non-conductingS)hasa60 conductivebacking(grapheneSubstrate).Thesecombined featureshaveneverbeenpossiblewithanypriorartcath 4.Thecathodeelectrodeofclaim1,whereinsaidcoated odeactivematerial. tionrepresentsaverysignificantaccomplishmentthatcan35 haveadramaticimpactontheemergenceofavibrantEV industry. Inconclusion,wehavesucesfulydevelopedanewand novelclasofhigh-capacitycathodeactivematerials(cath odeactivematerial-coatedgrapheneshets)andtherelating40 cathodeelectrodeforlithiumbateries.Suchagraphene enhancedparticulateplatformtechnologyhasthefollowing highlydesirablefeaturesandadvantages: (1)Thecathodeactivematerial-coatedgrapheneshetshave averyhighloading(percentage)oftheactivematerial, typicalyfrom60% to99% (moretypicalyfrom90to 95%)byweightofthecathodeactivematerial.Thecathode activematerialcoatingtypicalycovers60%-100%ofone oftheprimarySurfaceofagrapheneshet.Thelength/ widthofthesecoatedgrapheneshets,typicalyinthe50 rangeof0.5-10um,areamenabletothefabricationof poroussecondaryparticleshavingadiameterof1-10um, themostidealparticlesizesforelectrodefabricationease, lithiumiontransport,andlong-termcyclingstability. 45 55 2.Thecathodeelectrodeofclaim1,whereinatleast80% area of one of said Surfaces is coated with a cathode active material. (3)Grapheneshetsareofhighstrength,highelectricalcon ductivity,andhighthermalconductivity.Singlelayer65 graphenewasrecentlyfoundtoexhibitthehighestintrinsic 5.Thecathodeelectrodeofclaim1,whereinsaidcathode strengthandhighestintrinsicthermalconductivityamong activematerialisselectedfromaninorganicmaterial,an enabletheelectrodematerialstobereadilymadeintoelec trodeswithahightapdensityandlong-termcyclingsta bility. (7)Theembracinggrapheneshetsefectivelyisolatethe anodeactivematerials(e.g.,SiandSnO particles)from theelectrolyte,whichotherwisecouldreactwiththese activematerials,therebyreducingthereversiblecapacity. (8)QuiteSurprisingly,spray-dryingreadilyproduces graphene-enhancedparticulatesofasphericalshapethatis conducivetotheformationofinterconnectedporesinan actualelectrodetoenableeasypenetrationofelectrolyte. Theembracedprimaryparticles(coatedshets)havinga smallthicknes(typicalysmallerthan100nm)providea shortlithiumdifusionpathforlithiumtoenterandleave. Thisisparticularlydesirableforpowertolandelectric vehicleaplicationswherethebaterymustbecapableof beingchargedanddischargedatahighrate. 3.Thecathodeelectrodeofclaim1,whereinsaidcoated grapheneshetcontainsatleast60%byweightorbyvolume ofsaidcathodeactivematerialbasedonthetotalweightof saidcoatedgrapheneshet. grapheneshetcontainsatleast90%byweightorbyvolume ofsaidcathodeactivematerialbasedonthetotalweightof saidcoatedgrapheneshet.PDF Image | CATHODE ACTIVE MATERIAL-COATED DISCRETE GRAPHENE SHEETS FOR LITHIUM
PDF Search Title:
CATHODE ACTIVE MATERIAL-COATED DISCRETE GRAPHENE SHEETS FOR LITHIUMOriginal File Name Searched:
US9203084.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 |