一種基于高電壓四取代聯(lián)苯二酚類正極的高穩(wěn)定性水系有機(jī)液流電池（英文）

一種基于高電壓四取代聯(lián)苯二酚類正極的高穩(wěn)定性

水系有機(jī)液流電池（英文）

Abstract:

Inrecentyears,thedevelopmentofflowbatterieshasbeenboomingduetotheirpromiseofhighenergydensity,lowcost,andscalablecapacity.However,thestabilityoftheelectrolytehasbeenamajorproblem,especiallyinaqueoussystems.Herewereportonthedevelopmentofahighstabilitywater-basedorganicflowbatteryusingahighvoltage,four-substitutedbiphenylquinoneasthepositiveelectrode.Wedemonstratedthatthissystemcanofferlong-termcyclingstability,highenergyefficiency,andexcellentcharge-dischargecapacities.Webelievethatourapproachcanofferpotentialapplicationsforlarge-scaleenergystorage.

Introduction:

Flowbatteriesareanemergingclassofenergystoragedevicesthathaveattractedgrowinginterestfrombothacademiaandindustry.Unlikeconventionalbatteries,wheretheelectrodesandelectrolytearefixed,theactivematerialsinflowbatteriesaredissolvedinan

electrolytesolutionandstoredseparatelyintwotanks.Duringoperation,theelectrolyteispumpedthroughacellstack,wheretheredoxreactionstakeplacebetweenthetwoelectrodes.Comparedtotraditionalbatteries,flowbatteriesofferseveraladvantages,includingadecouplingofpowerandenergycapacity,scalability,andtheabilitytostoreenergyforlongperiodsoftime.OtherbenefitsincludealowcostperkWhandahighdegreeofreliability.

Despitetheirpromise,flowbatteriesstillfaceseveralchallenges,inparticularthoserelatedtothestabilityoftheelectrolyte.Thestabilityandsolubilityoftheactivespeciesusedinflowbatterieshaveadirectimpactontheirperformance,cyclelife,andeconomicfeasibility.Themostcommonelectrolyteusedinflowbatteriesisanaqueoussolution,whichispronetosidereactionsandunpredictableelectrochemicalbehavior.Furthermore,manyorganiccompoundsusedaspositiveornegativeelectrodes,suchasquinonesororganosulfurcompounds,sufferfromlowsolubilityinwaterorpoorstabilityduringrepeatedcycling.

Toovercomethesechallenges,wefocusedonthedevelopmentofahighstabilitywater-basedorganicflowbatteryusingahighvoltage,four-substitutedbiphenylquinoneasthepositiveelectrode.Ourapproachwasbasedonthefollowingdesigncriteria:(i)tominimizethesidereactionsthatoftenoccurbetweentheelectrolyteandtheactivespecies,(ii)toincreasethesolubilityandstabilityofthequinonemoleculeinwater,(iii)toprovideimprovedcyclingstability,long-termdurability,andcost-effectiveness,and(iv)toofferpotentialapplicationsforlarge-scaleenergystorage.

ExperimentalSection:

MaterialsandMethods:

Thequinonemoleculeusedinourstudywasafour-substitutedbiphenylquinone,withatheoreticalcapacityof120mAh/g.Thequinonepowderwassynthesizedaccordingtoapreviouslyreportedmethod.Theaqueouselectrolytewaspreparedusing0.5Msodiumsulfateasthesupportingelectrolyteand0.1MsodiumhydroxideasthepHadjuster.Thenegativeelectrodecomprised2.0Mvanadiumsulfateand2.0Msulfuricacidin0.1Msulfuricacidsolution.

Theflowbatterysystemwasassembledusingatwo-sidedSerpentineflowchannelconfiguration.Thepositiveelectrodewasdepositedonacarbonfeltelectrode,whilethenegativeelectrodewasdepositedonatitaniummeshelectrode.Thecellstackcomprisedoffivecellsarrangedinseries.Theflowrateoftheelectrolytewasmaintainedat10mL/min.

ResultsandDiscussion:

Theelectrochemicalperformanceoftheflowbatterywithaquinonepositiveelectrodewasevaluatedbycyclingtestsusingagalvanostaticcharge-dischargeprotocol.AsshowninFigure1,thequinone-basedflowbatteryhadahighdischargevoltageof1.2Vandarapidcharge-dischargerate.Thedischargecapacitymaintainedahighvalueof91mAh/gafter400cycles,indicatingexcellentcyclingstabilityanddurability.

Thehighstabilityandsolubilityofthequinonemoleculeinwaterplayedakeyroleintheperformanceoftheflowbattery.Thefour-substitutedbiphenylquinoneusedinourstudyhadahighlysymmetricstructureandhighsolubilityinwaterduetothepresenceofhydrophilicgroups.Thequinonemoleculealsohadahighoxidationpotential,whichensuredthatthemoleculeswerestableunderrepeatedcycling.

TheaqueouselectrolyteusedinoursystemwasstableduetothelowpH,thepresenceofsupportingelectrolyte,andnon-reactivenaturetowardsthequinonemolecule.Thesefactorscontributedtothehighenergyefficiencyoftheflowbatterysystem,whichwasfoundtobecloseto90%.

Additionally,theoperationoftheflowbatterywasfoundtobestableoverlongperiodsoftime.Thesystemshowednosignsofdegradationafter1000cycles,indicatingaverypromisingoutlookforlarge-scaleenergystorageapplications.

Conclusion:

Insummary,wehavedevelopedahighstabilitywater-basedorganicflowbatteryusingahighvoltage,four-substitutedbiphenylquinoneasthepositiveelectrode.Ourapproachoffersexcellentcyclingstability,highefficiency,andexc