金属氧化物_炭复合材料抑制锂硫电池穿梭效应的研究进展.pdf

Cite this:NewCarbonMaterials,2024,39(2):201-222DOI:10.1016/S1872-5805(24)60838-3A review of the use of metal oxide/carbon composite materials toinhibit the shuttle effect in lithium-sulfur batteriesZHOUZhi-qiang,WANGHui-min,YANGLu-bin,MACheng,WANGJi-tong*,QIAOWen-ming,LINGLi-cheng*（State Key Laboratory of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China）Abstract：Lithium-sulfur(Li-S)batteriesareamongthemostpromisingnext-generationelectrochemicalenergy-storagesystemsduetotheirexceptionaltheoreticalspecificcapacity,inexpensiveproductioncostandenvironmentalfriendliness.However,thepoorconductivityofSandLi2S,severelithiumpolysulfide(LiPS)shuttlingandthesluggishredoxkineticsofthephasetransformationgreatlyhindertheircommercialization.CarbonaceousmaterialscouldbepotentiallyusefulinLi-SbatteriestotackletheseproblemswiththeirhighspecificsurfaceareatohostLiPSsandsulfurandexcellentelectricalconductivitytoincreaseelectrontransferrate.However,non-polarcarbonmaterialsareunabletointeractcloselywiththehighlypolarpolysulfides,resultinginalowsulfurutiliza-tionandaseriousshuttleeffect.Becauseoftheiradvantagesofstrongpolarityandalargenumberofadsorptionsites,integratingtransitionmetaloxides(TMOs)withcarbon-basedmaterials(CMs)increasesthechemicaladsorptionofLiPSsandelectrochemicalreactionactivityforLiPSs.TheworkingprinciplesandmainchallengesofLi-Sbatteriesarediscussedfollowedbyareviewofre-centresearchontheex-situandin-situsynthesisofTMO/CMcomposites.TheformationofTMO/CMswiththedimensionalitiesofCMsfrom1Dto3Darethenreviewedtogetherwithwaysofchangingtheirstructure,includingheterostructuredesign,vacancyen-gineeringandfacetmanipulation.Finally,theoutlookforusingTMO/CMsinLi-Sbatteriesisconsidered.Key words:Transitionmetaloxides；Carbonmaterials；Modulationstrategies；Shuttleeffect；Lithium-sulfurbatteries1IntroductionTo alleviate the increasingly serious pollutioncausedby fossil fuels and cope with the rising de-mand for energy sources,the need for developingnovelenergy-storage systems has become more ur-gent than ever.Traditional LIBs(LIBs)have beenwidelyappliedinvariousfieldssuchasdailytrans-portation,routine work and social communication.However,lithiumironphosphateandternarypolymercommonlyusedincommercialLIBshavegraduallyapproachedtheiruppertheoreticalcapacity1.There-fore,as the requirement for electrochemical energystoragedevicescontinuestoincrease,LIBsarefind-ingitincreasinglydifficulttosatisfythepracticalde-mandsduetotheirrelativelylowenergydensity.Lithium-Sulfur(Li-S)batteriesareestablishedasoneofthemostpromisingcandidatesinthenext-gen-eration energy-storage systems due to merits ofabundant natural reserves of sulfur,higher theory capacity(1675 mAh g1)and longer cycling life comparedwith commercial LIBs2.Therefore,Li-S batterieshavereceivedconsiderableattentioninthepastfewdecades.However,numerous serious problems re-maintobesolved,suchasthepoorconductivityofSandLi2S,severeshuttleeffectofLiPSsintermediates,huge volume change of the electrode during thechargeanddischargeprocess,whichgreatlydiminishtheachievablecapacityperformanceandlifespanofLi-Sbatteries.Carbon-based materials(CM),such as carbonnanospheres,carbonnanotubesandgraphene,arethemostexcellentconductivesubstrateswidelyusedinthe design and synthesis of Li-S batteries cathodecomposites or modified separators because of theirstructural diversity,large specific surface area andReceived date：2023-10-24；Revised date：2023-12-27Corresponding author：WANGJi-tong,Professor.E-mail:;LINGLi-cheng,Professor.E-mail:Author introduction：ZHOUZhi-qiang,Ph.D.E-mail:Homepage:http:/ electrical conductivity.Well-designedporous structure and superb electron/ion transportchannelsprovidedbyCMcaneffectivelyenhancetheoverallconductivityandalleviatethevolumeexpan-sionofactivesubstancesduringrepeatedcyclingpro-cess35.However,the weak van der Waals interac-tion with LiPSs of intrinsic non-polar carbonaceousmaterialsresults in a massive loss of active sub-stancesandseriousshuttleeffect.Amongvariouspo-larmetal compounds,metal oxides possess the ad-vantagesofstrongpolarityandabundantadsorptionsites,butmostofthemaregenerallydifficulttobeusedassubstratematerialsaloneduetotheirinsuffi-cientelectricalconductivityandlimitedporousstruc-ture67.Therefore,metaloxidesareoftencompositedwithcarbonmaterialstoformTMOs-CMinthere-searchofactivematerialsinLi-Schemistry,contribut-ingtoincreasedelectronicconductivityandhighlyex-posedactivesites.Additionally,itisuniversallyac-knowledged that the excellent adsorption and rapidconversionabilityaretwoequallyimportantfactorsfor the“adsorption-diffusion-conversion”process inLi-S batteries.Although metal oxides supported onthecarbonsubstratehaveastrongaffinityforLiPSs,thesluggishcatalyticredoxkineticsoftrappedLiPSsresultsinpoorelectrochemicalperformanceofTMOs-CM,especiallyunderahighsulfurloadingandalowE/Sratio.Forthesereasons,themodulationstrategiessuchas heterostructures design,vacancies engineer-ingandfacetmanipulationcanbeemployedbytun-ingthe electronic structure and constructing inter-facestogreatlyimprovetheelectrochemicalproper-tiesofTMOs-CMandsignificantlypromotethecata-lyticconversionforLiPSsintermediates.Inthisre-view,theprinciplesandprimarychallengesofLi-Sbatteries are firstly introduced.Then the synthesismethodsandrecentresearchadvancesofTMOs-CMinthepastfewyearsarepresentedintermsofvariousdimensionalities(1D,2D,3D).Moreover,thehetero-structuredesign,vacancyengineeringandfacetma-nipulationofTMOs-CMcompositesarereviewedindetail.Finally,basedontherecentachievementsofTMOs-CMelectrocatalysts,the conclusion and out-lookarediscussedtoachievetheloftygoalofindus-trializingLi-Sbatteries(Fig.1).Allowing easy electrolyte penetrationVacancy engineeringFacets manipulatingPromoting electron/ion transportInhibiting shuttle effectStructural constructionsAccelerating redox kineticsHeterostructure designModulation strategiesSynthesis methodsPhysical confinement&strong adsorptionSuppressing lithium dendrities growthIn-situsynthesisEx-situsynthesis1D3D2DTMOs-CMfor Li-S batteriesFig.1Schematicillustrationofsynthesismethods,structuralconstructionsandmodulationstrategiesforTMOs-CM202新型炭材料（中英文）第39卷2 Principles and main challenges inLi-SbatteriesDifferent from the ion-insertion charge storagemechanismofLIBs,amultistepandreversiblereac-tion between S8 and lithium occurs in Li-S systemduringthecharge-dischargeprocess8.AsillustratedinFig.2,duringthedischargeprocess,thesolid-statesulfurisinitiallyreducedtolong-chainsolubleLiPSs(S82,S62,S42)at2.3V,whicharefurtherreducedtohighlyinsulatingLi2S2andLi2Sat2.1V.Reversibly,duringthechargeprocess,solid-stateLi2SandLi2S2speciesarere-oxidizedtolong-chainLiPSs,whichareeventually converted to sulfur through multiphaseconversion.Noteworthy,theliquid-solidtransforma-tionprocessat2.1Vcontributesto75%ofthetotalspecific capacity in Li-S batteries.However,thesevereshuttleeffectandsluggishreactionkineticsofliquid-solidconversionprocessduringthisstageleadstoasignificantdecreaseintheutilizationrateofact-ivesubstances,whichseriouslyinfluencestheelectro-chemicalperformanceofLi-Sbatteries9.Despitetheobviousmeritsofhighspecificcapa-city,lowcostofactivesulfurandmildenvironmentalpollution,some inherent drawbacks present a detri-mentaleffectontheelectrocatalyticability,includinglowconductivityofsulfurandshort-chainpolysulf-ides,severeshuttleeffectandhugevolumeexpansion.Shuttleeffectisoneofthemajorproblemswhichleadstoalowsulfurutilizationandseverecapacitydecayduringthechargeanddischargeprocess1011.Accordingtotheabove-mentionedcomplicatedmul-tistepreactionprocess,thesolubleintermediatesin-cludingLi2S8,Li2S6andLi2S4withhighmobilitydif-fusethroughtheseparatorfromcathodetoanodedur-ingthecycleduetotheconcentrationdifference.Asaresult,non-uniformdepositionofinsolubleandinsu-latingLi2Sareproducedontheanodicsurfacebythemigrated LiPSs,which will not only lead to severecorrosionoflithiummetal,butalsoincreasetheLi+transmission resistance between the anode and theelectrolyte.During the charge process,the formedpolysulfidestendtomigratebacktothecathodeandaresubsequentlyre-oxidizedtothelong-chainpoly-sulfides,resultinginalowCoulombicefficiencyandaseverecapacitydecay1213.Moreover,therepeateddepositionanddissolutionofLi2Swillinevitablyleadtothemassivelossofsulfurspeciesandthedestruc-tionofstructuralintegrityofelectrodematerial.Inthiscase,enhancing the adsorption ability and boostingthesluggishredoxkineticsofLiPSsintermediatesareessentialtoinhibitthepolysulfidesshuttlingandim-provetheelectrochemicalperformanceforLi-Sbat-teries.Volume expansion is another problem duringchargeanddischargeprocess.DuetotheremarkabledensitydifferencebetweenSandLi2S,ahugevolumeexpansion of 80%willinevitably occur during re-peatedcyclingwhichcausesalowutilizationrateofactivesulfurspeciesandanirreversibledestructionofthestructure1415.Inthiscase,withadestructedcath-odeintegrity,thedetachedsulfurspeciesloseeffect-ive electrical contact with conductive agents,whichwill further cause large polarization and low sulfurutilization.Therefore,electrodeconfigurationisoftenwell-designedtoprovideacertainporevolumetoal-leviatevolumeexpansionofsulfurspeciesandmain-tainstructuralstabilityofthecathode.ThelowconductivityofbothsulfurandLi2Sisthethirdproblemwhichresultsinslowelectrontrans-ferrateandsluggishredoxkinetics1617.Specifically,insulatingLi2Sgeneratedduringthechargeanddis-chargeprocessiscontinuouslydepositedonthesur-faceofelectrode,whichmayblocktheaccessofelec-tronsandLi+,covertheactivesitesprovidedbythedesignedmaterials and seriously constrain the reac-419 mAh/g1256 mAh/g2.8 V2.4 V2.1 V1.7 VVoltage(vs.Li/Li+)/VIIIIIINucleation of Li2SDischargingChargingReaction kineticsS8Li2S6Li2S4Li2S2SlowFastLi2SFig.2Typicalcharge/dischargecurveandmulti-phaseevolutionofLiPSsinLi-Sbatteries8.Reproducedwithpermission第2期ZHOUZhi-qiangetal:Areviewoftheuseofmetaloxide/carboncompositematerialstoinhibit203tionkineticsprocess.Inordertoimprovetheutiliza-tionrateofsulfurspecies,compositematerialsareal-waysdesignedtorealizeauniformdistributionofsul-fur,goodelectricalcontactwithconductivesubstrateandstrongadsorption-conversionabilityviatheaddi-tionofvariouselectrocatalysts.3 Synthesis methods and structuralconstructionsofTMOs-CM 3.1 Synthesis methods of TMOs-CMOverthepastfewdecades,considerableeffortshavebeendevotedtopreparingelectrocatalystswithactivespeciessupportedoncarbon-basedmaterialsofvariousdimensionsandnanostructurestoenhancetheelectrical/ionicconductivityofelectrodesandinhibittheseverepolysulfidesshuttling.Amongthesecom-positematerials,integratingTMOswithCMbydiffer-entsynthesisstrategieshasproveddesirableforelec-trochemicalperformanceinLi-Sbatteries.Inthissec-tion,the methods for synthesizing TMOs-CM com-positesaredividedintoex-situandin-situstrategies,whichwillbediscussedindetail.3.1.1Ex-situsynthesisEx-situsynthesisprimarilyconcernsthefabrica-tionofdesiredactivematerialsbeforehand,whicharethenencapsulatedorgraftedontothesurfaceofcar-bonaceousmaterialsviacovalentornon-covalentin-teractions18.Inordertoeffectivelyincreasethebind-ingability between metal catalysts and carbon sup-ports,strongoxidants,suchasHNO3,H2SO4,etc.,aregenerallyemployedtomodifycarbonaceousmateri-als with some polar groups1921.For example,grapheneoxidecanactasanexcellentsubstratetoin-tegratewithothermaterialsthroughelectrostaticinter-actionsduetoitsabundantoxygen-containingfunc-tionalgroups,andcanbeeasilytransformedintore-ducedgrapheneoxide(rGO)bysubsequentpyrolysistreatmentwithoutalteringitsoriginalnanostructure22.Onthisbasis,aVO2rGOcompositewaspreparedbyattachingVO2ontothesurfaceofgrapheneoxidewithlargeamountsofoxygen-containinggroups23.Inanothercase,Fe-basedmetal-organicframeworkwasmodifiedwithpositivelychargedPDDAandwaseas-ilyassembledwithnegativelychargedgrapheneox-ide.SubsequentlyFe3O4/NG/Gwasobtainedbyheattreatmentwhilemaintainingitshighlyorderedstruc-ture24.3.1.2In-situsynthesisIn-situsynthesisstrategiesforTMOs-CMcom-positeshavebeenextensivelyresearchedinLi-Ssys-tem,whichmainlyenablethenucleationandgrowthofactivematerialsonthecarbon-basedsubstrate.AndthenTMOs-CMareproducedthroughsubsequentcal-cinationprocesswithidealcompositionandstructure,includingnanotubes,nanocages,nanospheres,nano-flowers,nanosheets,etc.Variouschemicalandphysicalsynthesistechno-logies,suchassolvothermalprocess25,co-precipita-tion method26,template method2728,sol-gel treat-ment29,atomic layer deposition method3031,etc.,havebeenemployedforin-situstrategies.Intheliter-atures,hydrothermalandsolvothermalprocessesareone of the most commonly used synthesis methodssincethecatalystscanbewellcrystallizedontothesurfaceofcarbonsupportsresultinginremarkablyen-hancedactivesurface32.Recently,wedemonstratedthat ultra-small MnOx-CeO2 solidsolution nano-particlescouldbesuccessfullyprecipitatedandcrys-tallizedinthemesoporesofreducedgrapheneoxidebyafacilehydrothermalmethodusingureaasthepre-cipitant,whichpromotedtheadsorptionofLiPSsin-termediatesandboostedtheprecipitationandconver-sionofLi2Sasanadvancedfunctionalseparator33.Inanother case,Ni et al.34 reported that 1D WO3nanowires were encapsulated into the reducedgrapheneoxide in situ through hydrothermal ap-proach.The as-synthesized rGOWO3 with unique3D interconnected network not only possessed fastelectrontransportandLi+diffusionchannelsbetweensulfurandhostmaterials,butalsocontributedtopro-moting redox reaction kinetics and mitigating theshuttleeffect.Usingtheelectrospinningmethodfol-lowedbysubsequenthightemperaturetreatment,thepolarMnOnanoparticleswerewelldistributedinthemultichannelcarbonnanofibersbyChenetal35.Theexternal cross-linked carbon nanofibers and internal204新型炭材料（中英文）第39卷multichannelstructureprovidedsufficientelectrocata-lyticsitestoinhibitLiPSsdiffusion.Itisexpectedthattheabove-mentionedin-situmethodscouldbefurtherextendedtothedesignofothervariousidealTMOs-CMcompositeswithdesiredstructuresinthefuture.In-situ growth of carbon materials on as-pre-paredmetaloxideisalsoafeasiblemethodbycom-biningthemeritsofcarbonaceousmaterialsandmetaloxides,whichnotonlyensuresgoodstructuralstabil-ityandexcellentmechanicalpropertiesofthedesiredstructures,butalsoofferslargeSSAandimprovestheoverallelectricalconductivity.CVDmethodhasbeencommonlyemployedforin-situgenerationofcarbonmaterials on the surfaces of different metal oxides.For example,Yang et al.36 fabricatedZnO nano-particleswhichwereuniformlywrappedbyultrathingraphene-likecarbonshellsthroughCVDprocessbyemploying pyridine as carbon and nitrogen source.Benefitingfromthehollow3Dstructureandwell-dis-tributedZnOnanoparticles,excellentstructuralstabil-ity,goodelectricalconductivity,andstrongchemicaladsorptionforLiPSscouldbeachieved,resultinginsynergisticenhancementofelectrochemicalperform-anceforLi-Sbatteries.Inanothercase,Luoetal.37synthesized V2O3N,Ni-C hollow spheres throughCVD process by using octadecyl amine as carbonsource.ComparedwithpureV2O3,thehollowspheric-alstructurecomposedofnumerousnanosheetsonthesurfacesofV2O3N,Ni-Cwasconducivetothediffu-sionoflithiumionandthebufferingofvolume