The Four Components of a Li-ion Battery
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Nowadays,weseemanyhomeappliancegiantsrushingtolaunchcordlessstickvacuumcleaners.
Thisapplianceislovedbymanyusersastheyarelightinweightforevenachildtosteer,butyetboaststrongsuctionpower.
ThebirthofcordlessvacuumswaspossibleinlargepartduetoLi-ionbatteries.
Lightweight,highenergydensityLi-ionbatterieswithhighcapacityandefficiencythanotherbatteries
arewidelyappliedindiverseareasrangingfromsmallappliancesandITdevicestopowertools,energystoragesystems
andelectricvehicles.
Let'slookintoLi-ionbatteriesinsideouttoday.
Samsung SDI’s Li-ion
Batteries
Four Components of Li-ion Battery – Cathode, Anode, Electrolyte,
Separator
Li-ionbatteriesconsistoflargelyfourmaincomponents:cathode,anode,electrolyte,andseparator.
EverysinglecomponentofaLi-ionbatteryisessentialasitcannotfunctionwhenoneofthecomponentsismissing.
The Four Components of Li-ion Battery
▶“Cathode”determinesthecapacityandvoltageofaLi-ionbattery
ALithium-ionbatterygenerateselectricitythroughchemicalreactionsoflithium.
Thisiswhy,ofcourse,lithiumisinsertedintothebatteryandthatspaceforlithiumiscalled“cathode”.
However,sincelithiumisunstableintheelementform,thecombinationoflithiumandoxygen,lithiumoxideisusedforcathode.
Thematerialthatintervenestheelectrodereactionoftheactualbatteryjustlikelithiumoxideiscalled”activematerial”.
Inotherwords,inthecathodeofaLi-ionbattery,lithiumoxideisusedasanactivematerial.
Ifyoutakeacloserlookatthecathode,youwilllfindathinaluminumfoilusedtoholdtheframeofthecathodecoated
withacompoundmadeupofactivematerial,conductiveadditiveandbinder.
Theactivematerialcontainslithiumions,theconductiveadditiveisaddedtoincreaseconductivity;
andthebinderactsasanadhesivewhichhelpstheactivematerialandtheconductiveadditivetosettlewellonthealuminumsubstrate.
Cathodeplaysanimportantroleindeterminingthecharacteristicsofthebattery
asthebattery’scapacityandvoltagearedeterminedbyactivematerialtypeusedforcathode.
Thehigheramountoflithium,biggerthecapacity;andthebiggerpotentialdifferencebetweencathodeandanode,higherthevoltage.
Thepotentialdifferenceissmallforanodedependingontheirtypebutforcathode,thepotentialdifferenceisrelativelyhighingeneral.
Assuch,thecathodeplaysasignificantroleindeterminingthevoltageofthebattery.
▶”Anode”sendselectronsthroughawire
Justlikethecathode,theanodesubstrateisalsocoatedwithactivematerial.
Theanode’sactivematerialperformstheroleofenablingelectriccurrenttoflowthroughtheexternalcircuit
whileallowingreversibleabsorption/emissionoflithiumionsreleasedfromthecathode.
Whenthebatteryisbeingcharged,lithium ionsarestoredintheanodeandnotthecathode.
Atthispoint,whentheconductingwireconnectsthecathodetotheanode(dischargestate),
lithiumionsnaturallyflowback tothecathodethroughtheelectrolyte,
andtheelectrons(e-)separatedfromlithiumionsmovealongthewiregeneratingelectricity.
Foranodegraphitewhichhasastablestructureisused,andtheanodesubstrateiscoatedwithactivematerial,
conductiveadditiveandabinder.
Thankstographite’soptimalqualitiessuchasstructuralstability,lowelectrochemicalreactivity,
conditionsforstoringmuchlithiumionsandprice,thematerialisconsideredsuitabletobeusedforanode.
▶“Electrolyte”allowsthemovementofionsonly
Whenexplainingaboutcathodeandanode,itwasmentionedthatlithiumionsmovethroughtheelectrolyte
andelectronsmovethroughthewire.
Thisisthekeyinenablingtheuseofelectricityinabattery.
Ifionsflowthroughtheelectrolyte,notonlycan’tweuseelectricitybutsafetywillbejeopardized.
Electrolyteisthecomponentwhichplaysthisimportantrole.
Itservesasthemediumthatenablesthemovementofonlylithiumionsbetweenthecathodeandanode.
Fortheelectrolyte,materialswithhighionicconductivityaremainlyusedsothatlithiumionsmovebackandfortheasily.
Theelectrolyteiscomposedofsalts,solventsandadditives.
Thesaltsarethepassageforlithiumionstomove,thesolventsareorganicliquidsusedtodissolvethesalts,
andtheadditivesareaddedinsmallamountsforspecificpurposes.
Electrolytecreatedinthiswayonlyallowsionstomovetotheelectrodesanddoesn’tletelectronstopass.
Inaddition,themovementspeedoflithiumionsdependsontheelectrolytetype.
Thus,onlytheelectrolytesthatmeetstringentconditionscanbeused.
▶”Separator”,theabsolutebarrierbetweencathodeandanode
Whilethecathodeandanodedeterminethebasicperformanceofabattery,electrolyteandseparatordeterminethesafetyofabattery.
Theseparatorfunctionsasaphysicalbarrierkeepingcathodeandanodeapart.
Itpreventsthedirectflowofelectronsandcarefullyletsonlytheionspassthroughtheinternalmicroscopichole.
Therefore,itmustsatisfyallthephysicalandelectrochemicalconditions.
Commercializedseparatorswehavetodayaresyntheticresinsuchaspolyethylene(PE)andpolypropylene(PP).
Sofar,wehavelookedatthefourmaincomponentswhichdeterminetheperformanceofLi-ionbatteries.
Currently,SamsungSDIisstrengtheningR&Dofnewmaterialsfortheenhancementofbatteryperformance
whileceaselesslycontinuingitseffortstoimprovetheperformanceofexistingmaterialsandcoretechnologies.
Throughhighcapacity/highefficiencyLi-ionbatteryinnovation,
SamsungSDIseekstotaketheleadinthefuturebatteryindustrywhichwillenrichthelivesofhumanbeingsallacrosstheworld.
