Source: tshiab zog thawj coj, los ntawm
Paub meej: tam sim no, lithium ntsev hauv kev lag luam lithium-ion roj teeb electrolyte feem ntau yog LiPF6 thiab LiPF6 tau muab cov electrolyte zoo heev electrochemical kev ua tau zoo, tab sis LiPF6 tsis zoo thermal thiab tshuaj stability, thiab rhiab heev rau dej.
Tam sim no, lithium ntsev hauv kev lag luam lithium-ion roj teeb electrolyte yog LiPF6 thiab LiPF6 tau muab cov electrolyte zoo heev electrochemical kev ua tau zoo.Txawm li cas los xij, LiPF6 muaj qhov tsis zoo thermal thiab tshuaj lom neeg ruaj khov, thiab muaj kev nkag siab zoo rau dej.Nyob rau hauv qhov kev txiav txim ntawm H2O me me, cov kua qaub xws li HF yuav decomposed, thiab tom qab ntawd cov khoom zoo yuav raug corroded, thiab cov hlau hloov pauv cov ntsiab lus yuav yaj, thiab qhov saum npoo ntawm cov electrode tsis zoo yuav raug tsiv mus los ua kom puas SEI zaj duab xis. , Cov txiaj ntsig tau pom tias SEI zaj duab xis txuas ntxiv mus, uas ua rau lub peev xwm ntawm cov roj teeb lithium-ion tsis tu ncua.
Txhawm rau kov yeej cov teeb meem no, tib neeg tau cia siab tias lithium ntsev ntawm imide nrog H2O ruaj khov dua thiab zoo dua thermal thiab tshuaj lom neeg ruaj khov, xws li lithium ntsev xws li LiTFSI, lifsi thiab liftfsi, raug txwv los ntawm cov nqi thiab cov anions ntawm lithium ntsev. xws li LiTFSI tsis tuaj yeem daws rau corrosion ntawm Al foil, thiab lwm yam, LiTFSI lithium ntsev tsis tau siv rau hauv kev xyaum.Tsis ntev los no, VARVARA sharova ntawm German HIU lub chaw kuaj mob tau pom ib txoj hauv kev tshiab rau kev siv cov imide lithium ntsev ua cov khoom siv electrolyte.
Lub peev xwm qis ntawm graphite tsis zoo electrode nyob rau hauv Li-ion roj teeb yuav ua rau lub decomposition ntawm electrolyte ntawm nws nto, tsim passivation txheej, uas yog hu ua SEI zaj duab xis.SEI zaj duab xis tuaj yeem tiv thaiv electrolyte los ntawm decomposition ntawm qhov tsis zoo, yog li kev ruaj ntseg ntawm SEI zaj duab xis muaj qhov cuam tshuam tseem ceeb rau lub voj voog ruaj khov ntawm lithium-ion roj teeb.Txawm hais tias lithium ntsev xws li LiTFSI tsis tuaj yeem siv los ua cov kua qaub ua lag luam rau ib ntus, nws tau siv los ua cov khoom ntxiv thiab tau ua tiav cov txiaj ntsig zoo heev.VARVARA sharova xyaum sim pom tias ntxiv 2wt% LiTFSI hauv cov electrolyte tuaj yeem txhim kho lub voj voog kev ua haujlwm ntawm lifepo4 / graphite roj teeb: 600 cycles ntawm 20 ℃ thiab lub peev xwm poob qis dua 2%.Hauv pawg tswj hwm, cov electrolyte nrog 2wt% VC additive yog ntxiv.Nyob rau tib lub sijhawm, qhov poob ntawm lub peev xwm ntawm lub roj teeb nce mus txog 20%.
Txhawm rau txheeb xyuas cov txiaj ntsig ntawm cov khoom sib txawv ntawm kev ua haujlwm ntawm lithium-ion roj teeb, pawg dawb paug lp30 (EC: DMC = 1: 1) tsis muaj tshuaj ntxiv thiab pab pawg sim nrog VC, LiTFSI, lifsi thiab liftfsi tau npaj los ntawm varvarvara sharova raws.Kev ua tau zoo ntawm cov electrolytes no tau soj ntsuam los ntawm khawm ib nrab ntawm tes thiab tag nrho ntawm tes.
Daim duab saum toj no qhia txog voltammetric curves ntawm cov electrolytes ntawm pawg tswj dawb paug thiab pab pawg sim.Thaum lub sij hawm txo cov txheej txheem, peb pom tias qhov pom tseeb tam sim no ncov tau tshwm sim nyob rau hauv cov electrolyte ntawm pawg dawb paug ntawm li 0.65v, sib xws rau qhov txo decomposition ntawm EC hnyav.Lub decomposition tam sim no ncov ntawm pawg sim nrog VC additive hloov mus rau lub siab muaj peev xwm, uas yog vim hais tias lub decomposition voltage ntawm VC additive yog siab tshaj li ntawm EC, Yog li ntawd, lub decomposition tshwm sim ua ntej, uas tiv thaiv EC.Txawm li cas los xij, voltammetric curves ntawm cov electrolyte ntxiv nrog LiTFSI, lifsi thiab littfsi additives tsis txawv ntawm cov pab pawg neeg dawb paug, uas qhia tau hais tias cov imide additives tsis tuaj yeem txo qhov decomposition ntawm EC hnyav.
Daim duab saum toj no qhia txog kev ua haujlwm ntawm electrochemical ntawm graphite anode hauv cov electrolytes sib txawv.Los ntawm qhov ua tau zoo ntawm thawj tus nqi thiab kev tso tawm, coulomb efficiency ntawm pawg dawb paug yog 93.3%, thawj qhov ua haujlwm ntawm electrolytes nrog LiTFSI, lifsi thiab liftfsi yog 93.3%, 93.6% thiab 93.8%, feem.Txawm li cas los xij, thawj qhov ua tau zoo ntawm electrolytes nrog VC additive tsuas yog 91.5%, uas yog vim li cas thaum thawj lithium intercalation ntawm graphite, VC decomposes rau saum npoo ntawm graphite anode thiab noj ntau Li.
Kev sib xyaw ntawm SEI zaj duab xis yuav muaj kev cuam tshuam zoo rau cov ionic conductivity, thiab tom qab ntawd cuam tshuam qhov kev ua tau zoo ntawm Li ion roj teeb.Hauv kev ntsuas kev ua tau zoo, nws pom tau tias cov electrolyte nrog lifsi thiab liftfsi additives muaj peev xwm qis dua li lwm cov electrolytes hauv cov pa tawm tam sim no.Hauv kev ntsuas C / 2, lub voj voog kev ua haujlwm ntawm tag nrho cov electrolytes nrog imide additives yog qhov ruaj khov, thaum lub peev xwm ntawm cov electrolytes nrog VC additives txo.
Txhawm rau ntsuas kev ruaj ntseg ntawm electrolyte nyob rau lub sij hawm mus sij hawm ntev ntawm lithium-ion roj teeb, VARVARA sharova kuj tau npaj LiFePO4 / graphite tag nrho ntawm tes nrog khawm ntawm tes, thiab ntsuas lub voj voog kev ua haujlwm ntawm electrolyte nrog cov khoom sib txawv ntawm 20 ℃ thiab 40 ℃.Cov txiaj ntsig kev ntsuas tau pom nyob rau hauv cov lus hauv qab no.Nws tuaj yeem pom los ntawm lub rooj hais tias qhov ua tau zoo ntawm cov electrolyte nrog LiTFSI additive yog qhov siab dua li nrog VC additive thawj zaug, thiab kev ua haujlwm ntawm kev caij tsheb kauj vab ntawm 20 ℃ yog qhov hnyav dua.Lub peev xwm tuav tus nqi ntawm cov electrolyte nrog LiTFSI additive yog 98.1% tom qab 600 cycles, thaum lub peev xwm tuav tus nqi ntawm cov electrolyte nrog VC additive tsuas yog 79.6%.Txawm li cas los xij, qhov txiaj ntsig no ploj mus thaum lub electrolyte yog cycled ntawm 40 ℃, thiab tag nrho cov electrolytes muaj kev ua haujlwm zoo sib xws.
Los ntawm kev soj ntsuam saum toj no, nws tsis yooj yim pom tias lub voj voog kev ua haujlwm ntawm lithium-ion roj teeb tuaj yeem txhim kho tau zoo thaum lithium imide ntsev siv los ua cov khoom siv electrolyte.Txhawm rau kawm txog kev ua haujlwm ntawm cov khoom siv ntxiv xws li LiTFSI hauv cov roj teeb lithium-ion, VARVARA sharova tau txheeb xyuas qhov muaj pes tsawg leeg ntawm SEI zaj duab xis tsim rau saum npoo ntawm graphite anode hauv cov electrolytes sib txawv los ntawm XPS.Cov duab hauv qab no qhia tau hais tias XPS cov txiaj ntsig ntawm SEI zaj duab xis tsim nyob rau saum npoo ntawm graphite anode tom qab thawj zaug thiab 50 lub voj voog.Nws tuaj yeem pom tias LIF cov ntsiab lus hauv SEI zaj duab xis tsim nyob rau hauv electrolyte nrog LiTFSI additive yog ho ntau dua li cov electrolyte nrog VC additive.Kev soj ntsuam ntau ntxiv ntawm qhov muaj pes tsawg leeg ntawm SEI zaj duab xis qhia tau hais tias qhov kev txiav txim ntawm LIF cov ntsiab lus hauv SEI zaj duab xis yog lifsi> liftfsi> LiTFSI> VC> pawg dawb paug tom qab thawj lub voj voog, tab sis SEI zaj duab xis tsis hloov pauv tom qab thawj tus nqi.Tom qab 50 lub voj voog, LIF cov ntsiab lus ntawm SEI zaj duab xis hauv lifsi thiab liftfsi electrolyte poob los ntawm 12% thiab 43%, feem, thaum lub LIF cov ntsiab lus ntawm electrolyte ntxiv nrog LiTFSI nce 9%.
Feem ntau, peb xav tias cov qauv ntawm SEI membrane muab faib ua ob txheej: txheej txheej inorganic sab hauv thiab txheej txheej organic.Cov txheej txheem inorganic yog tsim los ntawm LIF, Li2CO3 thiab lwm yam inorganic Cheebtsam, uas muaj kev ua tau zoo ntawm electrochemical thiab ntau dua ionic conductivity.Cov txheej txheem txheej txheem txheej txheem yog tsim los ntawm cov khoom ntxeem tau electrolyte decomposition thiab polymerization khoom, xws li roco2li, PEO thiab lwm yam, uas tsis muaj zog tiv thaiv cov electrolyte, Yog li ntawd, peb cia siab tias SEI membrane muaj ntau inorganic Cheebtsam.imide additives tuaj yeem nqa ntau cov khoom siv tsis zoo LIF rau SEI daim nyias nyias, uas ua rau cov qauv ntawm SEI membrane ruaj khov, tuaj yeem tiv thaiv electrolyte decomposition zoo dua hauv cov txheej txheem roj teeb, txo Li noj, thiab txhim kho lub voj voog kev ua haujlwm ntawm lub roj teeb.
Raws li electrolyte additives, tshwj xeeb tshaj yog LiTFSI additives, imide lithium ntsev tuaj yeem txhim kho lub voj voog kev ua haujlwm ntawm lub roj teeb.Qhov no feem ntau yog vim qhov tseeb tias SEI zaj duab xis tsim nyob rau saum npoo ntawm graphite anode muaj ntau LIF, thinner thiab ruaj khov SEI zaj duab xis, uas txo cov decomposition ntawm electrolyte thiab txo qhov cuam tshuam tsis kam.Txawm li cas los xij, los ntawm kev sim cov ntaub ntawv tam sim no, LiTFSI additive yog tsim nyog rau siv nyob rau hauv chav tsev kub.Ntawm 40 ℃, LiTFSI additive tsis muaj qhov zoo dua VC additive.
Post lub sij hawm: Apr-15-2021