Tsawg-kub lithium ion roj teeb kev ua tau zoo dua

Lub hauv paus tseem ceeb rau kev ua haujlwm tsis zoo ntawm cov roj teeb uas muaj cov roj ntsha lithium-ion tseem muaj sib cav. Lub ntsiab yog vim li cas: viscosity ntawm electrolyte nce nyob rau ntawm qis kub thiab tus nqi poob qis; lub electrolyte / electrode interface membrane kuj thiab lub sij hawm hloov ntaub ntawv kuj tsis kam; lithium ions nyob hauv cov khoom siv ntawm lub cev Lub cev txav chaw nyob hauv nruab nrab poob qis. Raws li qhov tshwm sim, cov electrode polarization ntawm qhov kub tsis txias nce, thiab lub txim thiab cov khoom muaj peev xwm txo qis dua.

Thaum lub sijhawm ntsuas hluav taws xob qis ntawm cov roj ntsha lithium-ion, tshwj xeeb tshaj yog thaum lub sij hawm ntsuas hluav taws xob qis, lithium hlau nag lossis daus thiab qhov chaw tso tawm yuav tshwm sim hauv qhov tsis zoo electrode. Lub tshuab ua kua hlau lithium yog ib qho yooj yim rau cov tshuaj tiv thaiv nrog lub tshuab hluav taws xob thiab noj ntau ntawm cov roj electrolyte. Nyob rau tib lub sijhawm, lub thickness ntawm SEI zaj duab xis yog nce ntxiv, uas ua rau lub impedance ntawm qhov tsis zoo electrode saum zaj duab xis ntawm lub roj teeb txuas ntxiv, thiab polarization ntawm lub roj teeb nce ntxiv, uas yuav zoo heev rau cov kev ua haujlwm qis-qis, nws lub neej thiab kev ua tau zoo ntawm lub roj teeb.

Kev ntsuas roj tsawg-roj teeb roj txoj kev ua tau zoo dua Lub hom phiaj hloov kho los txhim kho qhov ntsuas hluav taws xob tsawg tsawg ntawm lub roj teeb los ntawm peb yam: zoo electrode, electrolyte thiab electrode tsis zoo.

1. Cov khoom siv cathode

Txoj hauv kev tau txais txiaj ntsig los txhim kho cov ion diffusion kev ua tau zoo ntawm cov ntaub ntawv cathode ntawm qhov kub tsawg yog:

1 Lub txheej txheej saum npoo ntawm cov khoom siv nquag lub cev nrog cov khoom zoo conductivity txhim kho qhov zoo ntawm kev sib raug zoo ntawm cov khoom siv electrode interface, txo cov interface impedance, thaum txo cov kev cuam tshuam sab ntawm qhov zoo ntawm cov khoom siv electrode thiab cov electrolyte, thiab stabilizing cov khoom qauv.

2 Cov khoom siv lub cev yog doped rau hauv kev txiav txim siab nrog Mn, Al, Cr, Mg, F thiab lwm yam, thiab txheej txheej kis ntawm cov khoom yog nce kom nce tus nqi sib txawv ntawm Li + hauv lub cev, txo cov diffusion tsis kam ntawm Li +, thiab txhim kho qhov kev ua haujlwm tsis zoo ntawm cov roj teeb.

3 Txo cov khoom ntu me me thiab ua kom luv luv Li + txoj kev tsiv teb tsaws. Nws yuav tsum tau taw qhia tias txoj kev no yuav ua rau kom qhov chaw tshwj xeeb ntawm thaj av ntawm cov khoom siv thiab ua rau kom cov tshuaj tiv thaiv sab nrog electrolyte.

2. Ntsuas Hluav Taws Xob

Ua ib feem tseem ceeb ntawm lithium ion roj teeb, lub tshuab hluav taws xob tsis tsuas txiav txim siab qhov kev tsiv teb ntawm Li + nyob rau theem ua kua, tab sis kuj koom rau hauv kev tsim cov SEI zaj duab xis, uas ua lub luag haujlwm tseem ceeb hauv kev ua haujlwm ntawm SEI zaj duab xis. Thaum muaj qhov kub qis, qhov pom kev ntawm qhov hluav taws xob nce, qhov kev coj ua poob qis, lub impedance ntawm SEI zaj duab xis nce, thiab kev sib raug zoo nrog cov ntaub ntawv zoo thiab tsis zoo, uas ua rau lub zog ntom ntom thiab lub zog ua haujlwm ntawm lub roj teeb.

Tam sim no, muaj ob txoj hauv kev los txhim kho qhov ntsuas kub tsawg los ntawm hluav taws xob:

(1) Txhim kho qhov ntsuas kub qis ntawm kev siv hluav taws xob los ntawm kev ua kom zoo dua rau cov lus ntawm cov kuab tshuaj thiab siv cov tshuaj electrolyte tshiab;

(2) Siv cov khoom siv tshiab los txhim kho cov yam ntxwv ntawm SEI zaj duab xis, ua rau nws zoo rau Li + conduction thaum kub tsawg.

1 Txhim kho cov tshuaj hnyav tov

Kev ntsuas qis ntawm qhov ntsuas hluav taws xob yog qhov tseem ceeb txiav txim siab los ntawm nws cov qis-kub eutectic kis. Yog tias lub ntsiab lus yaj siab dhau, cov xaim hluav taws xob tau yooj yim rau crystallize ntawm qhov kub tsis tshua muaj siab, uas yuav cuam tshuam loj heev ntawm cov khoom hluav taws xob. Ethylene carbonate (EC) yog cov kuab tshuaj tiv thaiv hluav taws xob tseem ceeb, tab sis nws cov ntsiab lus melting yog 36 ° C, thiab nws cov solubility hauv qhov hluav taws xob txo lossis txawm tias ua kom haum ntawm qhov kub tsawg, uas muaj qhov cuam tshuam ntau dua ntawm kev ntsuas kub ntawm qhov roj teeb. Los ntawm kev ntxiv cov ntsiab lus melting thiab qis viscosity Cheebtsam kom txo tau cov kuab tshuaj EC cov ntsiab lus, viscosity thiab eutectic kis ntawm cov electrolyte ntawm qhov kub tsawg tuaj yeem txo qis, thiab kev coj ua ntawm electrolyte tuaj yeem hloov kho.

2 Cov ntsev hluav taws xob tshiab

Electrolyte ntsev yog ib qho tseem ceeb ntawm cov khoom siv hluav taws xob, thiab nws kuj yog qhov tseem ceeb kom tau txais kev ua tau zoo kub tsawg. Tam sim no, kev lag luam electrolyte ntsev yog lithium hexafluorophosphate, thiab cov yeeb yaj kiab tsim SEI muaj qhov cuam tshuam loj, uas ua rau cov neeg ua haujlwm tsis zoo nyob hauv qis. Txoj kev loj hlob ntawm ib hom tshiab ntawm lithium ntsev yuav tawm. Lithium tetrafluoroborate muaj cov kav hlau me me, yooj yim los ua ke, thiab muaj qis dua kev ua tau zoo dua li LiPF6, tab sis muaj lub zog hloov mus ua haujlwm tsawg ntawm qhov kub qis, thiab muaj qhov ntsuas kub tsis zoo ua qhov ntsuas hluav taws xob.

3 quav ntxiv

Zaj yeeb yaj kiab SEI muaj qhov tseem ceeb heev ntawm kev ua haujlwm ntawm qhov ntsuas kub tsawg ntawm lub roj teeb. Nws yog ionic tus neeg xyuas pib thiab hluav taws xob insulator, thiab nws yog cov channel rau Li + mus cuag qhov hluav taws xob nto ntawm cov kua theem. Thaum muaj qhov kub qis, qhov tsis txaus ntseeg ntawm SEI zaj duab xis nce, thiab qhov tsis sib xws ntawm Li + hauv SEI zaj duab xis poob qis, uas tob tob qhov kev tsub zuj zuj ntawm cov nqi ntawm nplaim electrode, uas ua rau muaj qhov txo qis ntawm cov roj ntsha lithium. tso peev txheej ntawm cov graphite thiab ib qho kev ntxiv ntawm polarization. Los ntawm kev ua kom zoo rau cov muaj pes tsawg leeg thiab cov yeeb yaj kiab tsim cov xwm txheej ntawm SEI zaj duab xis, txhim kho cov ionic kev coj ua ntawm SEI zaj duab xis ntawm qhov kub tsis tshua muaj txiaj ntsig zoo rau kev txhim kho ntawm kev ua haujlwm tsawg-ntsuas kub ntawm lub roj teeb. Yog li no, kev txhim kho zaj duab xis-ntxiv cov yeeb yaj kiab nrog cov ua haujlwm ua kom zoo-qis kub yog qhov kev tshawb nrhiav tam sim no

Hauv txoj kev xaus, kev ua yeeb yaj kiab thiab kev tsim cov zaj duab xis tsis kam ntawm lub tshuab hluav taws xob muaj qhov cuam tshuam tseem ceeb rau kev ua haujlwm qis ntawm lithium-ion roj teeb. Rau cov hluav taws xob uas tsis tshua muaj hluav taws xob, nws yuav tsum tau nkag siab txog ntawm peb yam: electrolyte solvent system, lithium ntsev thiab ntxiv rau. Rau cov kua roj electrolyte, qhov kev daws teeb meem nrog kev tsis sib kis, tsis muaj viscosity thiab qhov siab dielectric tas li yuav tsum xaiv. Linear carboxylate cov kuab tshuaj muaj qhov ua haujlwm kub tsis tshua zoo, tab sis lawv muaj kev cuam tshuam zoo dua rau kev ua haujlwm ntawm lub voj voog, thiab xav kom phim cov roj cua cybic acid nrog cov siab ua kom qhov siab tsis tu ncua ntawm cov esters xws li EC thiab PC; rau cov roj ntsha lithium thiab cov kuab tshuaj ntxiv, qhov kev txiav txim siab tseem ceeb yog txo cov zaj duab xis tsis kam ua kom muaj zog thiab nce tus nqi ntawm kev ua tiav ntawm cov roj ntsha lithium. Tsis tas li ntawd, kev tsim nyog ntxiv cov roj ntsha lithium ntsev nyob rau ntawm qhov kub tsis tshua muaj peev xwm ua kom muaj qhov nce ntawm electrolyte thiab nce qhov kub tsis ua haujlwm.

3. Cov khoom siv anode

Qhov tsis zoo ntawm lub diffusion kinetics tej yam kev mob ntawm lithium ions nyob rau hauv cov pa roj carbon anode cov ntaub ntawv yog qhov tseem ceeb uas ua rau muaj kev ua haujlwm tsawg-tsawg ntawm cov roj ntsha lithium-ion. Yog li no, qhov hluav taws xob electrochemical ntawm qhov anode tau sib zog ua kom ruaj khov thaum lub sijhawm them nyiaj, uas yooj yim ua rau cov nag lossis daus ntawm cov xim hlau ntawm qhov chaw ntawm qhov anode.

Xaiv cov khoom haum anode yog qhov tseem ceeb los txhim kho kev ntsuas kub ntawm lub roj teeb. Nyob rau tam sim no, qhov kev ua kom zoo ntawm kev ua haujlwm qis-kub yog qhov tseem ceeb yog ua los ntawm cov txheej txheem ntawm kev kho saum npoo ntawm anode, txheej txheej saum npoo, doping kom cov txheej qhov chaw nyob, thiab tswj ntawm qhov loj me.

1 Nto kho

Kev kho deg nrog cov nplaim oxidation thiab fluorination. Kev kho saum npoo tuaj yeem txo qhov chaw nquag rau ntawm graphite nto, txo qhov tsis muaj peev xwm ua kom tsis muaj peev xwm, thiab tuaj yeem tsim ntau cov micro-nano qauv pores, uas yog qhov ua tau zoo rau Li + kis thiab txo qhov tsis haum.

2 Nto txheej

Cov xim pleev xim rau saum npoo av xws li cov xim carbon thiab cov xim hlau tsis tuaj yeem tsuas yog zam kev sib kis ncaj qha ntawm cov hluav taws xob tsis zoo thiab electrolyte, txhim kho kev sib raug zoo ntawm cov electrolyte thiab cov electrode tsis zoo, tab sis kuj tseem nce qhov kev coj ua ntawm graphite, muab ntau qhov chaw lithium ntxig rau, thiab ua Irreversible muaj peev xwm txo. Ntxiv rau, txheej txheej kis ntawm cov pa roj carbon phom lossis cov khoom siv carbon hnyav yog qhov loj dua qhov graphite. Txheej txheej txheej ntawm cov pa roj carbon muag lossis cov khoom siv carbon tsis zoo ntawm qhov hluav taws xob tsis zoo ua rau muaj qhov sib txawv ntawm cov roj ntsha lithium thiab txo qhov tsis kam ntawm SEI zaj duab xis, thiaj li txhim kho qhov ntsuas kub tsis zoo ntawm lub roj teeb. Qhov saum npoo ntawm ib qho me me ntawm Ag txhim kho qhov kev coj ua ntawm cov khoom siv tsis zoo electrode, ua rau nws muaj qhov ua tau zoo ntawm kev siv hluav taws xob tsis zoo ntawm qhov kub tsawg.

3 Ua kom muaj qhov sib txawv ntawm cov khaubncaws sab nraud povtseg graphite

Cov graphite anode muaj qhov sib quas ntu me me, thiab qhov tsis sib xws ntawm lithium ions ntawm graphite cov khaubncaws sab nraud povtseg tsawg dua, ua rau muaj ntau hom polarization. Kev qhia ntawm B, N, S, K thiab lwm yam hauv cov txheej txheem kev npaj graphite tuaj yeem hloov kho cov qauv ntawm graphite thiab nce Cov kab sib xyaw ua ke ntawm graphite txhim kho nws lub peev xwm tso tawm / intercalate lithium. Cov faus atomic ntawm P (0.106pm) muaj qhov loj dua li ntawm C (0.077pm). P doping tuaj yeem ua rau cov kab hluav taws xob sib xyaw ua ke ntawm graphite, txhim kho qhov muaj peev xwm diffusion ntawm lithium ions, thiab muaj peev xwm txhim kho nws. Cov ntsiab lus ntawm graphite crystallites hauv cov khoom siv carbon. Kev taw qhia ntawm K rau hauv cov khoom siv carbon yuav tsim cov sib txuas sib txuas ntawm KC8. Thaum cov poov tshuaj raug tshem tawm, kev cuam tshuam ntawm qhov sib txawv ntawm cov khoom siv carbon yuav nce ntxiv, uas tau txais txiaj ntsig zoo rau cov ntxig hluav taws xob ceev ceev ntawm cov roj ntsha, yog li txhim kho kev ua haujlwm tsis raug ntsuas kub ntawm lub roj teeb.

4 Tswj qhov loj me ntawm cov tsis zoo electrode

Qhov loj dua qhov tsis zoo electrode particle loj, ntev li ntawm cov roj ntsha lithium ion diffusion thiab qhov ntau dua qhov tsis zoo tiv thaiv, uas ua rau kom muaj zog ntau ntxiv polarization thiab tsis ua haujlwm kub tsis zoo. Yog li, kev tsim nyog txhawm rau txhawm rau qhov me me ntawm qhov tsis zoo ntawm cov khoom siv tsis zoo electrode tuaj yeem ua rau luv luv kev txav chaw ntawm lithium ions nruab nrab ntawm cov txheej graphite, txo cov diffusion tsis kam, nce thaj tsam electrolyte infiltration, thiab txhim kho kev ua haujlwm kub-tsawg ntawm cov roj teeb. Tsis tas li ntawd, graphite tsis zoo hluav taws xob los ntawm cov khoom tawg me me ntawm ib qhov me me muaj cov isotropy ntau dua, tuaj yeem muab ntau qhov chaw lithium tso tawm, txo cov duab polarization, thiab tuaj yeem txhim kho qhov ntsuas kub tsawg ntawm cov roj teeb.

Kev ua haujlwm tsis tshua muaj siab ntawm lithium-ion roj teeb yog qhov tseem ceeb ua rau txwv daim ntawv thov ntawm cov roj teeb lithium. Yuav ua li cas txhawm rau txhim kho kev ua haujlwm qis-qis ntawm lithium roj teeb tseem yog qhov kub thiab tsis yooj yim ntawm kev tshawb nrhiav tam sim no. Txhawm rau txhim kho kev ua kom qis-qis ntawm cov roj teeb lithium, cov cawv ntawm txhua yam tseem ceeb xws li cov electrode zoo, tsis zoo electrode, thiab cov roj ntsha hluav taws xob hauv lub roj teeb yuav tsum raug txiav txim siab. Los ntawm kev ua kom zoo ntawm cov roj ntsha electrolyte, ntxiv rau thiab lithium ntsev muaj pes tsawg leeg, kev ua kom zoo ntawm cov electrolyte tau zoo dua, thiab cov yeeb yaj kiab tsim ua kom tsawg dua; Cov khoom siv electrode raug hloov kho kev kho mob xws li doping, txheej, thiab granulation txhawm rau ua kom zoo dua cov khoom qauv thiab txo qhov interface tsis kam thiab cov tsis kam tiv thaiv ntawm Li + hauv cov khoom siv lub cev. Los ntawm tag nrho cov kev ua kom zoo ntawm lub roj teeb system, qhov kev pom zoo ntawm lub roj teeb lithium ntawm qhov ntsuas kub tsawg dua, thiab kev ua haujlwm ntawm qhov ntsuas kub tsawg dua ntawm lub roj teeb.