Kev hloov kho ntawm cov morphology thiab cov qauv ntawm graphite anodes thaum lub sijhawm ua haujlwm roj teeb ntev

Hauv cov tam sim no cov roj ntsha lithium-ion, cov khoom siv feem ntau anode rau cov roj teeb lithium feem ntau muab faib ua cov khoom siv roj carbon anode, lithium titanate, thiab cov khoom siv roj ntsha. Vim lub zog ceev cov kev txwv ntawm cov roj ntsha lithium titanate, qhov nthuav dav thiab qis dua ntawm cov khoom siv roj ntsha-silicon-based cov ntaub ntawv tau raug daws tsis tau zoo, thiab cov pa roj carbon-anode cov ntaub ntawv tseem nyob rau qhov tseem ceeb ntawm lithium roj teeb anodes.

Cov pa roj carbon anode cov ntaub ntawv tsuas yog tsim ntawm graphite, tawv tawv, thiab cov pa mos mos ua hluav taws xob. Graphite yog qhov khoom siv anode siv thoob plaws. Graphite muaj qhov zoo ntawm cov hluav taws xob muaj hluav taws xob ntau, cov khoom siv loj ntawm lithium ion diffusion coefficient, hloov ntim me me ua ntej thiab tom qab cov roj ntsha lithium, cov roj ntsha siab lithium muaj peev xwm thiab cov roj ntsha tsis muaj zog, thiab lwm yam, thiab tau dhau los ua cov lag luam tam sim no lithium-ion roj teeb anode khoom. Cov. Txhua tus paub tias lub roj teeb lithium yog lub roj teeb theem nrab uas ua haujlwm hauv" rooj zaum co co" qauv. Yog tias lithium ions kaw rov qab thiab rov nruab nrab ntawm graphite tsis zoo electrode thiab cov khoom siv electrode zoo tsis muaj qhov poob, ces qhov no yuav yog lub xeev zoo tshaj, tab sis qhov tseeb yog tias nws cuam tshuam los ntawm graphite txheej. Lithium roj teeb yuav maj mam ua kom zoo thiab puas tsuaj thaum siv vim muaj cov yam ntxwv ntawm ntau yam xws li cov qauv tsim, cov qauv siv lead ua ntawm cov khoom siv cathode, cov ion conductivity ntawm cov electrolyte, thiab qhov kub, kom txog thaum nws dhau los ua tsis muaj tseeb.

Hauv kev ua cov voj voog ntev ntev, yuav ua li cas morphology thiab cov qauv ntawm graphite anode ntawm lithium roj teeb hloov? Cov khoom siv electrode zoo yog lithium cobalt oxide, thiab cov khoom tsis zoo electrode yog graphite. Tom qab cov roj teeb lithium tau npaj, ib qho kev ntsuam xyuas mus ntev rau cov ntsuas tau ua rau nws, thiab kev ntsuas tau coj mus kuaj thiab soj ntsuam ntawm cov voj voog sib txawv.

1. Cov kev hloov kho ntawm cov qauv ntawm morphology ntawm graphite anode thaum lub sij hawm ntev cycling

Lub sijhawm ntsuas roj teeb lithium tau ua tiav nyob rau 1000 lub lis piam, feem tsis tuaj yeem (a), ua haujlwm (b), 600 mus (c), 700 kev voj voog (d), 800 mus (e), 900 mus (f), 1000 mus ( g) Daim txiag tsis zoo yog soj ntsuam los ntawm SEM, thiab qhov txiaj ntsig tau qhia nyob hauv Daim Duab 1:

Daim duab 1. SEM cov duab ntawm graphite anode tom qab kev sib txawv (5000 zaug)

Nws tuaj yeem pom tau tias cov khoom siv graphite, txawm hais tias tsis muaj kev sib txuas, ua kom rov ua haujlwm, lossis rov ua dua tshiab, muaj cov khoom sib txawv ntawm ntau pua ntawm nanometers txog kaum tawm micrometers, thiab cov particle loj faib tsis zoo li qub, thiab tsis muaj cov khoom graphite pom hauv qhov loj ntawm cov duab ntawm 5000 zaug. Cov tsos hloov. Hauv 50 txhiab lub sijhawm ua kom pom cov duab (Daim Duab 2), cov duab graphite tsis muaj txheej txheem muaj qhov chaw huv, thiab tsuas yog cov graphite nto uas pib ua kom pom cov yeeb yaj kiab zoo li cov yeeb yaj kiab, thiab cov yeeb yaj kiab zoo li cov duab yeeb yaj kiab tseem muaj nyob rau ntawm graphite nto thaum lub sijhawm them nyiaj thiab mus mus los. tshuaj Tom qab EDS kuaj thiab ntsuas, pom tau tias cov duab hluav taws xob tsis zoo ntawm cov kab hluav taws xob tsuas muaj C ua haujlwm. Txawm li cas los xij, ntxiv rau C lub caij, cov O tawm nyob rau hauv graphite electrode tom qab tsuas yog ua kom thiab muaj kev sib txawv. Qhov tshwm sim no qhia tau hais tias tsuas yog cov khoom siv thiab cycled graphite electrode tsim cov khoom siv O-muaj, uas ua pov thawj tias cov khoom siv zoo li zaj duab xis yog SEI zaj duab xis.

Daim duab 2. SEM cov duab ntawm graphite anode tom qab kev sib txawv (50,000 zaug)

2. Cov kev hloov kho ntawm cov qauv ntawm graphite anode thaum lub sij hawm ntev cycling

Cov kev hloov pauv ntawm graphite anode nyob rau lub sij hawm ntev cycling yog qhov tseem ceeb ntawm graphite txheej iav thiab qhov nce ntawm txheej txheej nrug. Cov kev kuaj XRD tau ua rau ntawm cov duab hluav taws xob tsis zoo ntawm cov duab hluav taws xob tsis zoo tom qab 600, 700, 800, 900 thiab 1000 mus, thiab cov txiaj ntsig tau qhia hauv daim duab 3. Raws li Bragg' s sib npaug thiab Scherrer' interlayer spacing d002, qhov ntsuas ntawm graphitization, grain loj npaum li cas Lc, thiab qhov loj ntawm La ntawm cov khoom siv graphite hauv cov kev taw qhia ntawm (002) cov twj siv lead ua lub iav yuav suav.

Daim duab 3. XRD qauv ntawm graphite anode tom qab kev sib txawv

Daim duab 4 qhia txog qhov nkhaus ntawm d002 thiab graphitization degree ntawm graphite electrode nrog cov lej ntawm kev voj voog. Thaum lub sijhawm tagnrho 1000 tus nqi tawm mus ncig, d002 thiab graphitization degree ntawm graphite electrode cov khoom hloov tsawg heev, tab sis d002 pom qhov nce zuj zus thiab cov graphitization degree pom qhov hloov zuj zus.

Daim duab 4. Graphite d002 thiab graphitization degree hloov pauv nrog cov lej ntawm kev voj voog

Daim duab 5 yog cov duab kab ntawm cov siv lead ua muaj qhov loj me Lc thiab La ntawm graphite electrode cov khoom raws li cov haujlwm ntawm cov lej mus. Cov Lc hauv kev tsis recirculating mus rau 1000 zaug qhia tau hais tias muaj kev hloov qis zuj zus, La tsis muaj txoj cai pauv hloov meej, thiab nws tus nqi hloov pauv nyob rau thaj tsam ntawm 47 ~ 49 nm

Daim duab 5. Graphite grain loj Lc thiab La pauv hloov nrog cov lej mus los

Cov qauv ntawm daim duab graphite tsis zoo lub pob thaum lub sij hawm ntev cycling tau pom, thiab qhov tshwm sim tau pom nyob hauv daim duab 6. Lub tshuab ua kom graphite tsis zoo electrode tau sib raug zoo thiab cov xwm txheej zoo li qub, tab sis cov khoom siv hluav taws xob maj pom ntawm ntug thiab winding crease ntawm graphite tsis zoo electrode tom qab 100 thiab 1000 mus. Txij li thaum cov tshuaj tiv thaiv kev ua haujlwm ntawm qhov kawg ntawm graphite ntug yog siab dua li ntawm qhov pib dav hlau, qhov tshuaj tiv thaiv sab tom kawg ntawm ntug yog qhov ntau dua, ua rau cov khoom graphite yuav poob qis dua. Thaum lub sijhawm tag nrho kev them nyiaj ntev thiab lub voj voog tawm, Lc tus nqi ntawm cov khoom siv graphite qhia muaj kev hloov zuj zus, thiab d002 qhia tau nce ntxiv. Tus nqi Lc yog cov khoom ntawm d002 thiab tus naj npawb ntawm graphite flakes hauv cov nplej, yog li tus naj npawb ntawm graphite flakes hauv cov grain qhia tau hais tias muaj kev hloov zuj zus. Cov kev hloov pauv hloov no yog macroscopically manifested los ntawm cov khoom siv graphite.

Daim duab 6. Digital duab ntawm graphite anode tom qab kev ua kom tsuas, 100 kev voj voog thiab 1000 mus

Thaum lub sijhawm siv cov roj teeb lithium, lub peev xwm ntawm kev sib tsoo feem ntau tshwm sim sai dua, thiab cov kev hloov hauv cov qauv ntawm graphite anode yog ib qho ntawm nws cov kev cuam tshuam tseem ceeb. Peb tseem tuaj yeem txiav txim siab qhov kev tsim nyog lub neej ntawm cov roj teeb lithium los ntawm kev txheeb xyuas cov kev hloov hauv cov qauv thiab morphology ntawm graphite tsis zoo electrode. Tsis txhob siv nws thaum nws nyob ze rau ntawm qhov ntsuas no kom tiv thaiv qhov tsis zoo electrode graphite los ntawm tev tawm ntawm cov ntawv ci tooj liab thiab ua rau muaj kev nyab xeeb.