Yog vim li cas rau qhov tob tsom xam ntawm lithium ion roj teeb

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Vim nws lub neej siab, lithium-ion roj teeb yog dav siv, nrog rau kev ncua sij hawm siv, qhov teeb meem ntawm bulging, kev nyab xeeb kev ua tau zoo tsis zoo tagnrho thiab circulating attenuation kuj hnyav dua, ua rau kev tsom xam thiab kev tiv thaiv ntawm lithium roj teeb qhov tob tshawb fawb. Raws li kev soj ntsuam kev tshawb fawb thiab kev txhim kho kev paub, tus sau tau faib qhov ua rau ntawm lithium roj teeb rau hauv ob pawg, ib qho yog bulging los ntawm lub thickness ntawm lub roj teeb (thib ob, vim yog bulging ntawm electrolytic kua oxidation). Hauv cov roj teeb sib txawv, qhov tseem ceeb ntawm cov roj teeb tuab yog txawv.

Piv txwv li, nyob rau hauv lub lithium titanate tsis zoo electrode roj teeb, lub ntsiab yam tseem ceeb ntawm bulging yog lub nruas; nyob rau hauv lub graphite tsis zoo electrode system, lub thickness ntawm tus ncej thickness thiab bulging ntawm lub gas mov Act. Ua ntej, lub thickness ntawm lub electrode ncej yog hloov nyob rau hauv kev siv ntawm lithium roj teeb, thiab lub thickness ntawm lub electrode ncej muaj ib tug thickness hloov, tshwj xeeb tshaj yog cov graphite tsis zoo electrode. Raws li cov ntaub ntawv uas twb muaj lawm, lub lithium roj teeb tau dhau los ntawm qhov kub thiab txias cia thiab kev ncig, uas yog nquag drumming, nrog ib tug tuab loj hlob ntawm li 6% mus rau 20%, nyob rau hauv qhov zoo polar expansion piv tsuas yog 4%, thiab qhov tsis zoo expansion piv yog 20%.

Lub hauv paus ua rau bulging ntawm lub thickness ntawm lithium roj teeb hloov yog cuam tshuam los ntawm lub essence ntawm graphite. Qhov tsis zoo electrode graphite cov ntaub ntawv LICX (LIC24, LiC12 thiab LIC6, thiab lwm yam), thiab qhov sib txawv ntawm cov kab sib txawv, ua rau muaj kev cuam tshuam ntawm microscopic sab hauv kev ntxhov siab, ua rau muaj qhov tsis zoo electrode nthuav dav.

Daim duab hauv qab no yog daim duab schematic ntawm cov qauv ntawm graphite tsis zoo electrode phaj nyob rau hauv qhov chaw thiab them thiab tawm. Kev nthuav dav ntawm graphite tsis zoo electrode feem ntau tshwm sim los ntawm kev nthuav dav tsis zoo. Qhov kev nthuav dav no feem ntau cuam tshuam nrog cov qauv ntawm qhov loj me, tus neeg sawv cev nplaum thiab daim ntawv ncej.

Kev nthuav dav ntawm qhov tsis zoo electrode ua rau cov tub ntxhais kom deform, thiab cov electrode yog tsim los ntawm lub diaphragm, thiab cov khoom tsis zoo electrode tsim microcrack, cov khoom electrolyte theem interface (SEI) zaj duab xis yog tawg thiab recombinant, siv electrolyte, thiab detergenting lub circulating kev ua tau zoo. Muaj ntau yam cuam tshuam rau qhov tsis zoo electrode ncej, thiab qhov xwm txheej ntawm cov nplaum thiab cov qauv tsis zoo ntawm daim ntawv polar yog ob qho tseem ceeb tshaj plaws. Cov nplaum feem ntau siv hauv graphite tsis zoo electrode yog SBR, sib txawv nplaum elastic modulus, sib txawv txhua yam muaj zog, thiab sib txawv los ntawm lub thickness ntawm lub phaj.

Lub zog dov tom qab txheej txheej tiav kuj cuam tshuam los ntawm cov tuab ntawm cov phaj tsis zoo electrode hauv lub roj teeb. Nyob rau hauv tib txoj kev ntxhov siab, qhov loj dua elastic modulus ntawm cov nplaum, qhov me me ntawm lub cev polarity shelving, thaum them, vim Li + embedding, graphite lattice expansion; Nyob rau tib lub sijhawm, vim qhov deformation ntawm qhov tsis zoo electrode hais thiab SBR, kev ntxhov siab sab hauv raug tso tawm tag nrho, ua rau qhov tsis zoo nthuav dav nce siab, SBR yog nyob rau theem ntawm cov yas deformation. Qhov no ntawm qhov kev nthuav qhia piv yog muaj feem xyuam rau cov elastic modulus ntawm SBR, uas ua rau qhov loj dua elastic modulus thiab lub zog ntawm SBR, thiab qhov me me ntawm expansion ntawm irreversible expansion.

Thaum tus nqi ntawm SBR tsis sib haum, lub siab sib txawv thaum lub cev pob txha raug nias, thiab qhov sib txawv ntawm lub siab ua rau cov kev ntxhov siab seem uas tsim los ntawm tus ncej, qhov ntau dua qhov kev ntxhov siab seem, ua rau lub cev ua ntej lub cev nthuav dav, tag nrho cov hluav taws xob thiab lub zog ntawm lub zog nthuav dav; Cov ntsiab lus SBR tsawg dua, qhov me me ntawm qhov siab ntawm dov, lub txee lub cev tsawg dua, qhov sib piv ntawm cov hluav taws xob ua ntej thiab cov khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob Qhov thib ob, kev siv roj av hauv cov roj teeb uas tshwm sim los ntawm cov roj teeb roj yog lwm qhov laj thawj tseem ceeb uas ua rau lub roj teeb bulging, txawm tias nws yog roj teeb lub voj voog, lub voj voog kub kub, qhov kub thiab txias, nws tsim cov roj sib txawv ntawm cov roj bulging. Raws li cov kev tshawb fawb tam sim no, cov ntsiab lus ntawm cov hluav taws xob core o yog tshwm sim los ntawm decomposition ntawm electrolyte.

Muaj ob qhov xwm txheej ntawm electrolyte decomposition, ib qho yog impurity ntawm electrolyte, xws li ya raws thiab hlau impurities rau decompose cov electrolytic kua, thiab lwm yam yog tsawg heev ntawm cov electrolytic kua, uas ua rau lub decomposition thaum them, thiab nyob rau hauv electrolyte Solvents xws li EC, DEC yog generated tom qab tau txais electrons, thiab cov tshuaj tiv thaiv dawb esters, hydroxycarbons. ethers thiab CO2, thiab lwm yam. Tom qab lub lithium roj teeb sib dhos ua tiav, ib qho me me ntawm cov roj tau tsim thaum lub sijhawm ua ntej, thiab cov roj av no yuav tsum tsis txhob muaj, thiab lub npe hu ua hluav taws xob core irreversible peev xwm poob. Thaum lub sij hawm thawj tus nqi thiab kev tso tawm, cov hluav taws xob mus txog cov tshuaj electrolytic nrog cov tshuaj electrolytic ntawm qhov tsis zoo electrode tom qab qhov hluav taws xob sab nraud, tsim cov roj.

Nyob rau hauv cov txheej txheem no, SEI yog tsim nyob rau saum npoo ntawm lub graphite tsis zoo electrode, nrog lub thickness ntawm lub SEI nce, electrons tsis tuaj yeem nkag mus rau oxidation tsis tu ncua ntawm electrolyte. Thaum lub sij hawm lub roj teeb lub neej, lub internal gas ntim yuav maj mam nce, vim hais tias ntawm impurities los yog ya raws nyob rau hauv lub electrolyte los yog nyob rau hauv lub electrolyte. Lub xub ntiag ntawm cov electrolyte yuav tsum tau tshem tawm hnyav, thiab kev tswj cov dej noo tsis nruj.

Cov tshuaj electrolytic nws tus kheej tsis nruj, thiab lub roj teeb pob tsis nruj me ntsis nkag mus rau hauv dej, lub angular dispensing yog tshwm sim, thiab overtilization ntawm lub roj teeb tseem yuav ua kom cov roj ntau lawm ntawm lub roj teeb. Ceev, ua rau lub roj teeb tsis ua hauj lwm. Hauv cov tshuab sib txawv, cov roj teeb ntau lawm txawv.

Nyob rau hauv graphite tsis zoo electrode roj teeb, qhov ua rau cov roj ntau lawm yog vim SEI zaj duab xis tsim, cov dej noo nyob rau hauv lub roj teeb yog ntau tshaj, thiab cov tshuaj ndlwg yog txawv txav, lub pob yog tsis zoo, thiab lub roj teeb florescent ratio nyob rau hauv lub lithium titanate NCM roj teeb system yuav tsum hnyav dua. Ntxiv rau qhov impurities, noo noo thiab cov txheej txheem hauv electrolyte, lwm qhov sib txawv ntawm graphite tsis zoo electrode yog lithium titanate tsis tuaj yeem zoo li graphite tsis zoo electrode roj teeb, tsim ib zaj duab xis SEI ntawm nws qhov chaw, inhibiting nws cov tshuaj tiv thaiv Electrolyte. Cov electrolyte yog ib txwm ncaj qha nyob rau hauv kev sib cuag nrog lub nto ntawm Li4Ti5O12 thaum lub sij hawm them nqi thiab tso tawm, uas ua rau ib tug tas mus li qhov chaw ntawm Li4Ti5O12 cov khoom, uas tej zaum yuav yog lub hauv paus ua rau Li4Ti5o12 roj teeb flatulence.

Cov khoom tseem ceeb ntawm cov roj yog H2, CO2, CO, CH4, C2H6, C2H4, C3H8, thiab lwm yam. Thaum cov lithium titanate cais nyob rau hauv cov electrolyte, tsuas yog CO2 yog tsim, thiab tom qab npaj ib lub roj teeb nrog ib tug NCM cov khoom, cov generated gases muaj xws li H2, CO2, CO, thiab ib tug me me ntawm gaseous hydrocarbons, thiab tom qab lub roj teeb, tsuas yog nyob rau hauv lub voj voog thaum them thiab tawm, H2 yog generated, thiab nyob rau hauv cov roj cov ntsiab lus ntau tshaj 5% H2. Qhov no qhia tau hais tias H2 thiab CO roj yuav raug tsim thaum lub sij hawm them nqi thiab tso tawm.

LIPF6 muaj nyob rau hauv cov electrolyte: PF5 yog cov kua qaub uas muaj zog heev, uas yog ib qho yooj yim ua rau decomposition ntawm carbonate, thiab nce tus nqi ntawm PF5 nrog kub nce. PF5 pab txhawb rau electrolyte decomposition, tsim CO2, CO thiab CXHY roj. Raws li kev tshawb fawb tseem ceeb, kev tsim cov H2 yog muab los ntawm cov dej hauv cov dej hauv electrolyte, tab sis cov ntsiab lus ntawm cov dej hauv cov electrolyte yog li ntawm 20 ¡Á 10-6, uas yog tsawg heev rau Yield ntawm H2.

Shanghai Jiaotong University Wu Kai qhov kev sim tau siv los ua lub roj teeb rau graphite / NCM111. Qhov kev txiav txim siab xaus lus tias qhov chaw ntawm H2 yog decomposition ntawm carbonate nyob rau hauv high voltage. Tam sim no, muaj peb txoj kev daws teeb meem rau kev tua cov roj teeb lithium titanate.

, Solvent system; thib peb, txhim kho cov txheej txheem roj teeb.