Lub caij ntuj no los txog, saib qhov ntsuas kub qis ntawm cov roj teeb lithium-ion

Kev ua haujlwm ntawm cov roj teeb lithium-ion tau cuam tshuam zoo heev los ntawm lawv cov yam ntxwv kinetic. Vim Li + yuav tsum tau desolvated ua ntej thaum nws yog embedded nyob rau hauv cov khoom graphite, nws yuav tsum tau noj ib tug npaum li cas ntawm lub zog thiab cuam tshuam lub diffusion ntawm Li + mus rau hauv lub graphite. Ntawm qhov tsis sib xws, thaum Li + raug tso tawm los ntawm cov khoom siv graphite rau hauv cov kev daws teeb meem, cov txheej txheem kev daws teeb meem yuav tshwm sim ua ntej, thiab cov txheej txheem kev daws teeb meem tsis xav tau kev siv hluav taws xob. Li + tuaj yeem tshem tawm cov graphite sai sai, uas ua rau muaj qhov tsis zoo ntawm cov khoom siv graphite. Nyob rau hauv lub discharge acceptability.

Ntawm qhov kub thiab txias, cov yam ntxwv kinetic ntawm qhov tsis zoo graphite electrode tau txhim kho thiab ua rau tsis zoo. Yog li ntawd, lub electrochemical polarization ntawm qhov tsis zoo electrode yog qhov tseem ceeb heev thaum lub sij hawm them tus txheej txheem, uas tuaj yeem yooj yim ua rau nag lossis daus ntawm cov hlau lithium rau saum npoo ntawm qhov tsis zoo electrode. Kev tshawb fawb los ntawm Christian von Lüders ntawm Technical University of Munich, lub teb chaws Yelemees, tau qhia tias ntawm -2 ° C, tus nqi them tshaj C / 2, thiab cov hlau lithium nag lossis daus yog nce ntxiv. Piv txwv li, ntawm tus nqi C / 2, tus nqi ntawm lithium plating ntawm qhov tawm tsam electrode yog hais txog tag nrho cov nqi. 5.5% ntawm lub peev xwm tab sis yuav ncav cuag 9% hauv qab 1C magnification. Lub precipitated metallic lithium tuaj yeem txhim kho ntxiv thiab nws thiaj li dhau los ua lithium dendrites, tho los ntawm diaphragm thiab ua rau luv luv ntawm qhov zoo thiab tsis zoo electrodes. Yog li ntawd, nws yog ib qho tsim nyog kom tsis txhob them lub roj teeb lithium-ion ntawm qhov kub thiab txias kom ntau li ntau tau. Thaum nws yuav tsum tau them lub roj teeb ntawm qhov kub thiab txias, nws yog ib qho tseem ceeb uas yuav tau xaiv ib qho me me tam sim no los them cov roj teeb lithium-ion kom ntau li ntau tau thiab muab tag nrho cov roj teeb lithium-ion tom qab them nyiaj kom ntseeg tau tias cov roj ntsha lithium precipitated los ntawm qhov tsis zoo electrode. tuaj yeem hnov ​​​​mob nrog graphite thiab rov muab tso rau hauv qhov tsis zoo graphite electrode.

Veronika Zinth thiab lwm tus ntawm Technical University of Munich tau siv neutron diffraction thiab lwm txoj hauv kev los kawm txog lithium evolution tus cwj pwm ntawm lithium-ion roj teeb ntawm qhov kub ntawm -20 ° C. Neutron diffraction yog ib txoj kev tshawb nrhiav tshiab hauv xyoo tas los no. Piv nrog XRD, neutron diffraction yog rhiab heev rau lub teeb teeb (Li, O, N, thiab lwm yam), yog li nws yog qhov tsim nyog rau kev sim tsis muaj kev puas tsuaj ntawm lithium-ion roj teeb.

Hauv kev sim, VeronikaZinth siv NMC111 / graphite 18650 roj teeb los kawm txog lithium evolution tus cwj pwm ntawm lithium-ion roj teeb ntawm qhov kub thiab txias. Lub roj teeb tau them thiab tawm thaum lub sijhawm kuaj raws li cov txheej txheem qhia hauv daim duab hauv qab no.

Cov duab hauv qab no qhia txog theem hloov ntawm qhov tsis zoo electrode nyob rau hauv qhov sib txawv SoCs thaum lub sij hawm them nyiaj thib ob ntawm C / 30 tus nqi them. Nws tuaj yeem zoo li ntawm 30.9% SoC, cov theem ntawm qhov tsis zoo electrode feem ntau yog LiC12, Li1-XC18, thiab ib qho me me ntawm LiC6 Composition; Tom qab SoC tshaj 46%, qhov sib txawv ntawm LiC12 txuas ntxiv txo, thaum lub zog ntawm LiC6 tseem nce ntxiv. Txawm li cas los xij, txawm tias tom qab qhov kawg nkaus xwb, vim tias tsuas yog 1503mAh raug them ntawm qhov kub thiab txias (lub peev xwm yog 1950mAh ntawm chav tsev kub), LiC12 muaj nyob rau hauv qhov tsis zoo electrode. Piv txwv tias qhov them tam sim no raug txo rau C / 100. Nyob rau hauv tas li ntawd, lub roj teeb tseem tuaj yeem tau txais lub peev xwm ntawm 1950mAh ntawm qhov kub thiab txias, uas qhia tau hais tias qhov txo qis ntawm lub zog ntawm lithium-ion roj teeb ntawm qhov kub thiab txias yog feem ntau yog vim qhov tsis zoo ntawm kinetic tej yam kev mob.

Daim duab hauv qab no qhia txog theem hloov ntawm graphite hauv qhov tsis zoo electrode thaum them nyiaj raws li C / 5 tus nqi ntawm qhov kub ntawm -20 ° C. Nws tuaj yeem pom tias theem hloov ntawm graphite yog qhov sib txawv loj piv rau C / 30 tus nqi them. Nws tuaj yeem pom los ntawm daim duab uas thaum SoC> 40%, lub zog theem ntawm lub roj teeb LiC12 nyob rau hauv C / 5 tus nqi txo qis qis dua, thiab qhov nce ntawm LiC6 theem zog kuj tseem qis dua li ntawm C / 30. tus nqi. Nws qhia tau hais tias ntawm tus nqi siab ntawm C / 5, tsawg dua LiC12 txuas ntxiv mus rau intercalate lithium thiab hloov mus rau LiC6.

Daim duab hauv qab no piv rau theem hloov pauv ntawm qhov tsis zoo graphite electrode thaum them nyiaj ntawm C / 30 thiab C / 5 tus nqi, feem. Daim duab qhia tau hais tias rau ob qhov sib txawv ntawm kev them nqi, lithium-pheej theem Li1-XC18 zoo sib xws. Qhov txawv yog feem ntau xav txog nyob rau hauv ob theem ntawm LiC12 thiab LiC6. Nws tuaj yeem pom los ntawm daim duab uas cov theem hloov pauv nyob rau hauv qhov tsis zoo electrode yog ze ze ntawm thawj theem ntawm kev them nqi raws li ob tus nqi them. Rau theem LiC12, thaum lub peev xwm them tau nce mus txog 950mAh (49% SoC), qhov kev hloov pauv pib tshwm sim txawv. Thaum nws los txog 1100mAh (56.4% SoC), LiC12 theem nyob rau hauv ob qhov kev nthuav dav pib qhia qhov sib txawv tseem ceeb. Thaum them tus nqi qis ntawm C / 30, qhov poob ntawm LiC12 theem yog ceev heev, tab sis qhov poob ntawm LiC12 theem ntawm C / 5 tus nqi yog qeeb dua; uas yog hais, lub kinetic tej yam kev mob ntawm lithium insertion nyob rau hauv lub tsis zoo electrode deteriorate nyob rau hauv qis kub. , LiC12 ntxiv intercalates lithium los tsim LiC6 theem ceev txo. Raws li txoj cai, LiC6 theem nce sai heev ntawm tus nqi qis ntawm C / 30 tab sis qeeb qeeb ntawm tus nqi ntawm C / 5. Qhov no qhia tau hais tias ntawm C / 5 tus nqi, ntau petite Li yog embedded nyob rau hauv lub siv lead ua qauv ntawm graphite, tab sis dab tsi yog qhov nthuav yog hais tias lub roj teeb lub peev xwm (1520.5mAh) ntawm tus nqi C / 5 yog siab dua li ntawm C. / 30 tus nqi them. Lub hwj chim (1503.5mAh) yog siab dua. Qhov ntxiv Li uas tsis muaj nyob rau hauv qhov tsis zoo graphite electrode yog yuav ua rau precipitated ntawm graphite nto nyob rau hauv daim ntawv ntawm hlau lithium. Cov txheej txheem sawv tom qab qhov kawg ntawm kev them nyiaj kuj ua pov thawj qhov no los ntawm sab - me ntsis.

Cov duab hauv qab no qhia txog theem qauv ntawm qhov tsis zoo graphite electrode tom qab them nyiaj thiab tom qab tso rau 20 teev. Thaum kawg ntawm kev them nyiaj, cov theem ntawm qhov tsis zoo graphite electrode yog qhov sib txawv heev nyob rau hauv ob tus nqi them. Ntawm C / 5, qhov sib piv ntawm LiC12 hauv graphite anode yog siab dua, thiab feem pua ​​​​ntawm LiC6 qis dua, tab sis tom qab sawv rau 20 teev, qhov sib txawv ntawm ob tau dhau los ua tsawg.

Daim duab hauv qab no qhia txog theem hloov ntawm qhov tsis zoo graphite electrode thaum lub sijhawm 20h cia txheej txheem. Nws tuaj yeem pom los ntawm daim duab tias txawm hais tias cov theem ntawm ob qhov kev tawm tsam electrodes tseem sib txawv heev thaum pib, raws li lub sij hawm cia nce, ob hom kev them nyiaj theem ntawm cov graphite anode nyob rau hauv lub magnification tau hloov heev ze. LiC12 tuaj yeem hloov pauv mus rau LiC6 txuas ntxiv mus rau hauv cov txheej txheem txee, qhia tias Li yuav txuas ntxiv mus rau hauv cov graphite thaum lub sij hawm txee. Qhov no ntawm Li yog zoo li yog hlau lithium precipitated nto ntawm qhov tsis zoo graphite electrode ntawm qhov kub thiab txias. Kev soj ntsuam ntxiv tau pom tias thaum kawg ntawm kev them nyiaj ntawm C / 30 tus nqi, qib ntawm lithium intercalation ntawm qhov tsis zoo graphite electrode yog 68%. Tseem, qib ntawm lithium intercalation tau nce mus rau 71% tom qab tso tseg, nce 3%. Thaum kawg ntawm kev them nyiaj ntawm C / 5 tus nqi, lithium insertion degree ntawm qhov tsis zoo graphite electrode yog 58%, tab sis tom qab tso rau 20 teev, nws nce mus rau 70%, tag nrho nce ntawm 12%.

Cov kev tshawb fawb saum toj no qhia tau hais tias thaum them nyiaj ntawm qhov kub thiab txias, lub roj teeb muaj peev xwm yuav txo qis vim qhov tsis zoo ntawm cov kinetic tej yam kev mob. Nws tseem yuav precipitate cov lithium hlau rau ntawm qhov chaw ntawm qhov tsis zoo electrode vim qhov txo qis ntawm graphite lithium insertion tus nqi. Txawm li cas los xij, tom qab lub sijhawm khaws cia, Qhov no ntawm cov hlau lithium tuaj yeem muab tso rau hauv graphite dua; Hauv kev siv tiag tiag, lub sijhawm txee feem ntau luv luv, thiab tsis muaj kev lees paub tias tag nrho cov hlau lithium tuaj yeem nkag mus rau hauv cov graphite dua, yog li nws yuav ua rau qee cov hlau lithium txuas ntxiv nyob rau hauv qhov tsis zoo electrode. Lub roj teeb lithium-ion saum npoo yuav cuam tshuam rau lithium-ion roj teeb lub peev xwm thiab tuaj yeem tsim cov lithium dendrites uas ua rau muaj kev phom sij rau kev nyab xeeb ntawm lithium-ion roj teeb. Yog li ntawd, sim kom tsis txhob them lub roj teeb lithium-ion ntawm qhov kub thiab txias. Tsawg tam sim no, thiab tom qab teeb tsa, xyuas kom lub sijhawm txee txaus kom tshem tawm cov hlau lithium hauv qhov tsis zoo graphite electrode.

Kab lus no feem ntau yog hais txog cov ntaub ntawv hauv qab no. Daim ntawv tshaj tawm tsuas yog siv los qhia thiab tshuaj xyuas txog cov haujlwm tshawb fawb, kev qhia hauv chav kawm, thiab kev tshawb fawb txog kev tshawb fawb. Tsis siv rau kev lag luam. Yog tias koj muaj teeb meem kev cai lij choj, thov koj xav tiv tauj peb.

1.Rate peev xwm ntawm graphite cov ntaub ntawv raws li tsis zoo electrodes nyob rau hauv lithium-ion capacitors, Electrochimica Acta 55 (2010) 3330 - 3335, SRSivakkumar, JY Nerkar, AG Pandolfo

2.Lithium plating nyob rau hauv lithium-ion roj teeb soj ntsuam los ntawm voltage so thiab nyob rau hauv situ neutron diffraction, Phau ntawv Journal of Power Sources 342(2017)17-23, Christian von Lüders, Veronika Zinth, Simon V.Erhard, Patrick J.Osswald, Michael Hofman , Ralph Gilles, Andreas Jossen

3.Lithium plating nyob rau hauv lithium-ion roj teeb ntawm sub-ambient kub soj ntsuam los ntawm nyob rau hauv situ neutron diffraction, Journal of Power Sources 271 (2014) 152-159, Veronika Zinth, Christian von Lüders, Michael Hofmann, Johannes Hattendorff, Irmgard Erhard, Joana Rebelo-Kornmeier, Andreas Jossen, Ralph Gilles