Optimization of ionic conductivity in solid electrolytes through.pdf

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1、ViewArticleOnline/JournalHomepage/TableofContentsforthisissuePCCPDynamicArticleLinksCitethis:Phys.Chem.Chem.Phys.,2012,14,8369–8375www.rsc.org/pccpPAPEROptimizationofionicconductivityinsolidelectrolytesthroughdopant-dependentdefectclusteranalysisabacddZhi-PengLi,*ToshiyukiMori,JinZouandJoh

2、nDrennanReceived16thMarch2012,Accepted10thApril2012DOI:10.1039/c2cp40845gAtomisticsimulationbasedonanenergyminimizationtechniquehasbeencarriedouttoinvestigatedefectclustersofR2O3(R=La,Pr,Nd,Sm,Gd,Dy,Y,Yb)solidsolutionsinfluoriteCeO2.Defectclusterscomposedofuptosixoxygenvacanciesandtwelveacc

3、ompanieddopantcationshavebeensimulatedandcompared.Thebindingenergyofdefectclustersincreasesasafunctionoftheclustersize.Ahighlysymmetricdumbbellstructurecanbeformedbysixoxygenvacancies,whichisconsideredasabasicbuildingblockforlargerdefectclusters.Thisisalsobelievedtobeauniversalvacancystruc

4、tureinanoxygen-deficientfluoritelattice.Nevertheless,theaccuratepositionsofassociateddopantsdependonthedopantradius.Asaconsequence,thecorrelationbetweendopantsizeandoxygen-ionconductivityhasbeenelucidatedbasedontheordereddefectclustermodel.Thisstudyshedslightonthechoiceofdopantsfromaphysical

5、perspective,andsuggeststhepossibilityofsearchingforoptimalsolidelectrolytematerialsthroughatomisticsimulations.I.Introductionexperimentalresultshavedemonstratedthat,withinthedilutedopantsolute,theionicconductivitywillmonotonicallyFluoriteoxidesdopedwithaliovalentcationsarewell-knownincreas

6、easthedopantconcentrationincreases.Afterreachingfastoxide-ionconductormaterialsthathavebeenwidelysomecriticalpoint,however,theconductivitywilldecreaseasutilizedinoxygensensors,electrochemicaloxygenpumpsthedopinglevelincreases.Forinstance,theconductivityof1–3andsolidoxidefuelcells(SOFCs).Th

7、isisbecausethesolidGd-,Yb-andLa-dopedceriawilldecreasebeyondthedopantPublishedon13April2012.DownloadedbyJilinUniversityon07/03/201402:48:36.solutionsoffluoriteoxides(e.g.,ZrO2,CeO2)containingconcentrationabout11–14at.%.11,12Theobtainedmaximumlower-valencecation