electrochemical capacitors：电化学电容器

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1、ElectrochemicalCapacitorsBackgroundDuringperiodsofhighpeakoutput,significantvoltagedropsareseeninconventionalbatteriesmakingthemincapableofsatisfyingthehighpowerrequirementsofvariousconsumerelectronicdevices.Electrochemicalcapacitorsareattractiveforload-levelingtoalleviatethi

2、sproblem.Reducingthepeakpowerdemandonbatterieswillincreaseoperatingtimesforelectronicdevicessuchaslap-tops,cellularphones,camcorders,andotherportabledevices.Onthesamecriteriacapacitorsalsoformasignificantcomponentofanelectricvehiclebasedonanyalternativefueltechnology(batterie

3、s/naturalgas/fuelcell).Currentresearchfocusesexclusivelyonthedevelopmentofcapacitors,whicharebasedeitheroncarbonsoronmetaloxides.Howeverthisapproachdoesnotsatisfythetwinrequirementsofbothhighpowerandlowcost.Thelaterfactoriscriticalinsuccessfulcommercializationofanelectricvehi

4、cle.OurApproachWehavedevelopedhybridmetaloxide-carbonsupercapacitorswithsuperiorenergyandpowerdensitiesascomparedtobarecarbonusinganovelthinfilmdepositionprocess.ThenovelroutetosynthesizingthesematerialsaffordseaseincontrollingRumetalloadingandoptimizingparticlesize.Thisleads

5、tothedevelopmentofRuOx-Cmaterialswithhighratesofreactionandfastdiffusionrates.Thisinturnwouldtranslatedirectlyintocapacitorswithsuperiorenergyandpowerdensitiescapableofsatisfyingthehighpowerrequirementsofelectronicdevicesandelectricvehicles.Incontrasttopseudo-capacitors,theca

6、pacitanceofcarbon-basedmaterialsisdirectlylinkedtotheirspecificsurfacearea.However,increasingthisareabeyondacertainpointdoesnottranslatetoasimilarincreaseinthecapacitance.Theincreasedsurfaceareaarisesduetotheformationofmicroporesofsizelessthan10.Theseporesremaininaccessibleto

7、theelectrolyteandhencedonotformadoublelayer.Hence,thereexistsamaximumlimittotheenergyandpowerdensityrealizablefromanycarbonaceousmaterial.Alternatively,pseudocapacitorshavesignificantlylargeenergydensitiesascomparedtocarbonbaseddoublelayercapacitors.Thisadvantageofpseudocapac

8、itorsisoffsetbytheirhighcostascomparedtocarbon.Theadvantagesaccruedf