Unveiling the Mystery: Super Theoretical Peev Xwm hauv Lithium-ion roj teeb
By hoppt
Vim li cas lithium roj teeb tshwm sim super theoretical muaj peev xwm tshwm sim
Hauv cov roj teeb lithium-ion (LIBs), ntau qhov kev hloov pauv hlau oxide-raws li electrodes muaj peev xwm khaws cia tsis zoo tshaj lawv qhov kev xav. Txawm hais tias qhov tshwm sim no tau tshaj tawm dav dav, cov txheej txheem physicochemical hauv cov ntaub ntawv no tseem tsis tau paub thiab tseem muaj kev sib cav.
Profile ntawm cov txiaj ntsig
Tsis ntev los no, xibfwb Miao Guoxing los ntawm University of Waterloo, Canada, xibfwb Yu Guihua los ntawm University of Texas ntawm Austin, thiab Li Hongsen thiab Li Qiang los ntawm Qingdao University tau koom tes luam tawm cov ntawv tshawb fawb ntawm Cov Khoom Siv Xwm Txheej raws li lub npe ntawm "Ntxiv cov peev txheej hauv Hloov pauv hlau oxide lithium-ion roj teeb qhia los ntawm hauv situ magnetometry". Hauv kev ua haujlwm no, cov kws sau ntawv tau siv nyob rau hauv situ magnetic xyuas los ua kom pom qhov muaj zog ntawm qhov chaw muaj zog ntawm cov hlau nanoparticles thiab tias ntau tus spin-polarized electrons tuaj yeem khaws cia rau hauv cov hlau nanoparticles uas tau txo qis, uas yog zoo ib yam nrog rau spatial charge mechanism. Tsis tas li ntawd, qhov nthuav tawm spatial charge mechanism tuaj yeem txuas ntxiv mus rau lwm qhov kev hloov pauv ntawm cov hlau sib txuas, muab cov lus qhia tseem ceeb rau kev tsim cov khoom siv hluav taws xob siab heev.
Tshawb nrhiav cov ntsiab lus
(1) Ib tug raug Fe tau kawm los ntawm kev siv in-site magnetic xyuas cov txheej txheem3O4/ Evolution ntawm cov hluav taws xob qauv hauv Li roj teeb;
(2) qhia tias Fe3O4 Hauv / Li system, lub peev xwm saum npoo yog qhov tseem ceeb ntawm lub peev xwm ntxiv;
(3) Cov txheej txheem deg capacitance ntawm cov hlau nanoparticles tuaj yeem txuas mus rau ntau qhov kev hloov pauv hlau sib txuas.
Phau ntawv thiab phau ntawv qhia
- Cov yam ntxwv ntawm tus yam ntxwv thiab electrochemical zog
Monodisperse hollow Fe yog tsim los ntawm cov pa hydrothermal txoj kev3O4Nanospheres, thiab tom qab ntawd ua ntawm 100 mAg-1Charge thiab tso tawm ntawm qhov ceev tam sim no (Daim duab 1a), thawj qhov tso tawm muaj peev xwm yog 1718 mAh g-1, 1370 mAhg hauv lub sijhawm thib ob thiab thib peb, hwm. 1 Thiab 1,364 mAhg-1, deb tshaj 926 mAhg-1 Txoj kev xav ntawm kev cia siab. BF-STEM cov duab ntawm cov khoom tso tawm tag nrho (Daim duab 1b-c) qhia tias tom qab lithium txo qis, Fe3O4 Cov nanospheres tau hloov mus rau hauv me me Fe nanoparticles ntsuas txog 1 - 3 nm, dispersed hauv Li2O centre.
Txhawm rau ua kom pom qhov hloov pauv hauv cov hlau nplaum thaum lub voj voog hluav taws xob, qhov nkhaus magnetization tom qab tag nrho tawm mus rau 0.01 V tau txais (Daim duab 1d), uas qhia txog tus cwj pwm superparamagnetic vim yog tsim ntawm nanoparticles.
Daim duab 1 (a) ntawm 100 mAg−1Fe ntawm kev caij tsheb kauj vab ntawm qhov ceev tam sim no3O4 / Tus nqi tam sim no tsis tu ncua thiab tawm nkhaus ntawm Li roj teeb; (b) tag nrho lithium Fe3O4BF-STEM duab ntawm cov electrode; (c) lub xub ntiag ntawm Li nyob rau hauv aggregate2High-resolution BF-STEM duab ntawm ob qho tib si O thiab Fe; (d) Fe3O4Lub hysteresis nkhaus ntawm lub electrode ua ntej (dub) thiab tom qab (xiav), thiab Langevin haum nkhaus ntawm lub tom kawg (ntsuab).
- Real-time nrhiav pom ntawm cov qauv thiab sib nqus evolution
Txhawm rau muab cov electrochemistry nrog Fe3O4O ntawm cov qauv thiab sib nqus hloov pauv txuas rau Fe3O4 Cov Electrodes tau raug rau hauv situ X-ray diffraction (XRD) thiab hauv situ magnetic xyuas. Fe nyob rau hauv ib tug series ntawm XRD diffraction qauv thaum lub sij hawm pib tawm los ntawm lub qhib-circuit voltage (OCV) mus rau 1.2V3O4Cov diffraction peaks tsis tau hloov loj heev nyob rau hauv ob qho tib si siv los yog txoj hauj lwm (Daim duab 2a), qhia tau hais tias Fe3O4Tsuas tau ntsib Li intercalation txheej txheem. Thaum them rau 3V, Fe3O4 Cov qauv anti-spinel tseem nyob ruaj khov, tawm tswv yim tias cov txheej txheem nyob rau hauv qhov hluav taws xob qhov rais no muaj zog heev. Ntxiv nyob rau hauv-situ magnetic xyuas ua ke nrog tas li tam sim no cov nqi-tso cov kev ntsuam xyuas tau ua los soj ntsuam seb magnetization hloov zuj zuj nyob rau hauv lub sij hawm (Daim duab 2b).
Daim duab 2 Tus cwj pwm ntawm in-situ XRD thiab kev soj ntsuam sib nqus.(A) hauv situ XRD; (b) Fe3O4Electrochemical charge-discharge nkhaus nyob rau hauv 3 T siv magnetic teb thiab coj reversible nyob rau hauv situ magnetic teb.
Kom tau txais kev nkag siab yooj yim dua ntawm cov txheej txheem hloov dua siab tshiab no nyob rau hauv cov nqe lus ntawm kev hloov pauv magnetization, cov lus teb sib nqus tau sau nyob rau lub sijhawm tiag tiag thiab cov theem hloov pauv nrog cov tshuaj electrochemically tsav (Daim duab 3). Nws yog qhov tseeb heev tias thaum thawj qhov tso tawm, Fe3O4 Cov lus teb magnetization ntawm cov electrodes txawv ntawm lwm lub voj voog vim yog Fe thaum lub sij hawm thawj lithalization3O4Due mus rau irreversible theem hloov tshwm sim. Thaum lub peev xwm poob mus rau 0.78V, Fe3O4The antispinel theem tau hloov mus rau muaj Li2 Cov chav kawm FeO halite qauv ntawm O, Fe3O4The theem tsis tuaj yeem rov qab los tom qab them nyiaj. Raws li txoj cai, cov hlau nplaum poob sai sai rau 0.482 μb Fe-1. Raws li lithialization tshwm sim, tsis muaj theem tshiab tsim, thiab kev siv ntawm (200) thiab (220) chav kawm FeO diffraction peaks pib tsis muaj zog.equal Fe3O4 Tsis muaj qhov tseem ceeb XRD ncov khaws cia thaum lub electrode yog lig lig (Daim duab 3a). Nco ntsoov tias thaum lub Fe3O4 electrode tawm ntawm 0.78V mus rau 0.45V, qhov magnetization (los ntawm 0.482 μ b Fe−1Increased mus rau 1.266 μ bFe−1), Qhov no tau ntaus nqi los ntawm kev hloov pauv ntawm FeO rau Fe. Tom qab ntawd, thaum kawg ntawm qhov tso tawm, cov hlau nplaum tau maj mam txo mus rau 1.132 μ B Fe-1. Qhov kev tshawb pom no qhia tau hais tias tag nrho cov hlau txo qis Fe0Nanoparticles tseem tuaj yeem koom nrog cov tshuaj tiv thaiv lithium, yog li txo cov hlau nplaum ntawm cov electrodes.
Daim duab 3 Nyob rau hauv situ kev soj ntsuam ntawm lub sij hawm hloov thiab cov lus teb sib nqus. (b) Fe3O4In situ magnetic quab yuam ntsuas ntawm electrochemical cycles ntawm / Li hlwb ntawm daim ntawv thov magnetic teb ntawm 3 T.
- Fe0 / Li2Surface capacitance ntawm O system
Fe3O4 Cov kev hloov pauv sib nqus ntawm cov electrodes tshwm sim ntawm qhov tsis tshua muaj hluav taws xob, ntawm qhov muaj peev xwm ntxiv hluav taws xob feem ntau tsim tawm, qhia tias muaj cov khoom siv tsis tau pom hauv lub xov tooj ntawm tes. Txhawm rau tshawb xyuas lub peev xwm lithium cia mechanism, Fe tau kawm los ntawm XPS, STEM thiab sib nqus kev ua tau zoo spectrum3O4Electrodes ntawm magnetization peaks ntawm 0.01V, 0.45V thiab 1.4V los txiav txim qhov chaw ntawm qhov sib nqus hloov. Cov txiaj ntsig tau pom tias lub sijhawm sib nqus yog qhov tseem ceeb cuam tshuam rau kev hloov pauv ntawm cov hlau nplaum, vim tias qhov ntsuas Fe0 / Li2The Ms ntawm O system tsis cuam tshuam los ntawm cov hlau nplaum anisotropy thiab interparticle coupling.
Txhawm rau kom nkag siab ntxiv txog Fe3O4 Lub kinetic zog ntawm cov electrodes ntawm qhov tsis tshua muaj hluav taws xob, cyclic voltammetry ntawm qhov sib txawv scan nqi. Raws li pom nyob rau hauv daim duab 4a, lub voj voos voj voog voltammogram nkhaus tshwm nyob rau hauv qhov voltage ntawm 0.01V thiab 1V (Daim duab 4a). Daim duab 4b qhia tau hais tias Fe3O4A capacitive teb tshwm sim ntawm electrode. Nrog rau cov lus teb zoo sib nqus ntawm cov nqi tam sim no thiab cov txheej txheem tawm (Daim duab 4c), cov hlau nplaum ntawm cov electrode poob ntawm 1V mus rau 0.01V thaum lub sij hawm tso tawm, thiab nce ntxiv thaum lub sij hawm them nqi, qhia tias Fe0O ntawm lub capacitor zoo li. cov tshuaj tiv thaiv saum npoo yog rov qab heev.
Daim duab 4 electrochemical zog thiab nyob rau hauv situ magnetic characterization ntawm 0.011 V.(A) Lub cyclic voltammetric nkhaus.(B) tus nqi b yog txiav txim los ntawm kev sib raug zoo ntawm lub ncov tam sim no thiab tus nqi scan; (c) qhov kev hloov pauv ntawm qhov sib nqus ntawm qhov sib nqus ntawm qhov kev them nyiaj-kho tawm hauv qab 5 T siv cov hlau nplaum.
Cov lus hais saum toj no Fe3O4 Cov khoom siv hluav taws xob, cov qauv thiab cov khoom sib nqus ntawm cov electrodes qhia tias cov roj teeb ntxiv tau txiav txim siab los ntawm Fe0Lub spin-polarized nto capacitance ntawm nanoparticles yog tshwm sim los ntawm kev sib nqus sib nqus. Lub spin-polarized capacitance yog qhov tshwm sim ntawm spin-polarized nqi tsub zuj zuj ntawm lub interface thiab tuaj yeem tso tawm cov lus teb sib nqus thaum lub sij hawm them thiab tawm. loj nto-rau-ntim ratios thiab paub ib tug siab ceev ntawm lub xeev nyob rau hauv lub Fermi theem vim lub heev localized d orbitals. Raws li Maier tus qauv theoretical ntawm spatial charge storage, cov kws sau ntawv qhia tias cov khoom siv hluav taws xob ntau tuaj yeem khaws cia hauv cov kab sib txuas ntawm cov hlau Fe nanoparticles, uas tuaj yeem pom hauv Fe / Li3Creating spin-polarized nto capacitors hauv O nanocomposites ( Daim duab 4).
graph 5Fe/Li2A Schematic sawv cev ntawm qhov chaw capacitance ntawm spin-polarized electrons ntawm O-interface.(A) schematic daim duab ntawm spin polarization xeev ceev ntawm qhov chaw ntawm ferromagnetic hlau hais (ua ntej thiab tom qab tso tawm), contra rau ntau spin polarization ntawm hlau; (b) tsim ntawm qhov chaw them nqi cheeb tsam nyob rau hauv lub nto capacitor qauv ntawm overstored lithium.
Cov ntsiab lus thiab Outlook
TM / Li tau tshawb xyuas los ntawm kev soj ntsuam zoo hauv qhov chaw sib nqus 2Qhov kev hloov pauv ntawm cov qauv hluav taws xob sab hauv ntawm O nanocomposite los qhia qhov chaw ntawm qhov muaj peev xwm ntxiv rau lub roj teeb lithium-ion no. Cov txiaj ntsig tau pom tias, ob qho tib si hauv Fe3O4 / Li qauv cell system, electrochemically txo Fe nanoparticles tuaj yeem khaws cov khoom siv hluav taws xob ntau ntawm spin-polarized, uas tshwm sim vim muaj peev xwm ntawm tes ntau dhau thiab hloov pauv ntawm cov hlau nplaum interfacial magnetism. Cov kev sim ntxiv validated CoO, NiO, thiab FeF2And Fe2Lub xub ntiag ntawm xws li capacitance nyob rau hauv N electrode cov ntaub ntawv qhia lub hav zoov ntawm spin-polarized nto capacitance ntawm hlau nanoparticles nyob rau hauv lithium ion roj teeb thiab nteg lub hauv paus rau daim ntawv thov ntawm no spatial nqi cia mechanism nyob rau hauv lwm yam kev hloov. hlau compound-based electrode cov ntaub ntawv.
Cov ntawv nyeem txuas
Lub peev xwm cia ntxiv hauv kev hloov pauv hlau oxide lithium-ion roj teeb qhia los ntawm situ magnetometry (Nature Materials, 2020, DOI: 10.1038/s41563-020-0756-y)
Kev cuam tshuam ntawm lithium electrode wafer tsim qauv thiab electrode wafer tsis raug ntawm kev ua haujlwm
- Pole zaj duab xis tsim foundation tsab xov xwm
Lub lithium roj teeb electrode yog txheej txheej ntawm cov khoom, sib npaug rau cov kua dej hlau. Lithium ion roj teeb electrode txheej tuaj yeem suav tias yog cov khoom siv sib xyaw, feem ntau muaj peb ntu:
(1) Cov khoom siv hluav taws xob;
(2) cov theem ntawm cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob (carbon adhesive phase);
(3) Pore, sau nrog cov electrolyte.
Lub ntim kev sib raug zoo ntawm txhua theem yog qhia raws li:
Porosity + nyob teeb meem ntim feem + carbon nplaum theem ntim feem = 1
Kev tsim ntawm lithium roj teeb electrode tsim yog ib qho tseem ceeb heev, thiab tam sim no cov kev paub yooj yim ntawm lithium roj teeb electrode tsim tau luv luv qhia.
(1) Lub peev xwm theoretical ntawm cov khoom siv electrode Lub peev xwm theoretical ntawm cov khoom siv electrode, uas yog, lub peev xwm muab los ntawm tag nrho cov lithium ions hauv cov khoom koom nrog cov tshuaj tiv thaiv electrochemical, nws tus nqi yog xam los ntawm cov kab zauv hauv qab no:
Piv txwv li, LiFePO4 Cov molar loj yog 157.756 g / mol, thiab nws lub peev xwm theoretical yog:
Qhov xam tus nqi no tsuas yog lub peev xwm theoretical gram xwb. Txhawm rau kom ntseeg tau cov qauv rov qab ntawm cov khoom siv, qhov tseeb lithium ion tshem tawm coefficient tsawg dua 1, thiab qhov tseeb gram peev ntawm cov khoom yog:
Qhov tseeb gram peev ntawm cov khoom = theoretical muaj peev xwm ntawm lithium ion unplugging coefficient
(2) Roj teeb tsim hluav taws xob thiab cov khoom siv hluav taws xob tsawg dua los ntawm cov khoom siv hauv qab no: Roj Teeb Ntaw Cov Khoom Muaj Peev Xwm
Ntawm lawv, qhov ntom ntom ntawm cov txheej yog qhov tseem ceeb ntawm cov qauv tsim. Thaum lub compaction ceev tsis hloov, qhov nce ntawm txheej txheej ntom ntom txhais tau hais tias cov ncej ntawv thickness nce, electron transmission nrug nce, thiab electron kuj nce, tab sis qhov nce qib yog txwv. Nyob rau hauv daim ntawv tuab electrode, qhov nce ntawm cov migration impedance ntawm lithium ions nyob rau hauv cov electrolyte yog lub ntsiab yog vim li cas cuam tshuam rau tus piv ntawm cov yam ntxwv. Xav txog qhov porosity thiab pore twists, qhov kev txav mus los ntawm ions hauv qhov pore yog ntau zaus ntau dua li qhov tuab ntawm cov ntawv ncej.
(3) Qhov piv ntawm qhov tsis zoo-zoo muaj peev xwm piv N / P tsis zoo rau lub peev xwm zoo yog txhais raws li:
N / P yuav tsum muaj ntau dua 1.0, feem ntau 1.04 ~ 1.20, uas feem ntau yog nyob rau hauv kev ruaj ntseg tsim, los tiv thaiv sab tsis zoo lithium ion los nag lossis daus yam tsis tau txais, tsim los xav txog cov txheej txheem muaj peev xwm, xws li txheej txheej deviation. Txawm li cas los xij, thaum N / P loj dhau lawm, lub roj teeb yuav poob tsis muaj peev xwm rov qab tau, ua rau lub roj teeb muaj peev xwm tsawg thiab qis zog roj teeb.
Rau lithium titanate anode, qhov zoo electrode tshaj tsim tau txais yuav, thiab lub peev xwm roj teeb yog txiav txim siab los ntawm lub peev xwm ntawm lithium titanate anode. Qhov zoo tshaj plaws tsim yog tsim rau kev txhim kho qhov kub thiab txias kev ua tau zoo ntawm lub roj teeb: cov roj kub kub feem ntau yog los ntawm qhov tsis zoo electrode. Nyob rau hauv qhov zoo tshaj tsim, lub peev xwm tsis zoo yog tsawg, thiab nws yooj yim dua los tsim SEI zaj duab xis rau saum npoo ntawm lithium titanate.
(4) Compaction ceev thiab porosity ntawm txheej Nyob rau hauv cov txheej txheem ntau lawm, txheej compaction ceev ntawm lub roj teeb electrode yog xam los ntawm cov qauv hauv qab no. Xav txog tias thaum daim ntawv ncej yog dov, cov ntawv hlau yog txuas ntxiv, qhov ntom ntom ntawm cov txheej tom qab cov menyuam raug xam los ntawm cov qauv hauv qab no.
Raws li tau hais ua ntej lawm, txheej txheej muaj cov khoom siv nyob rau theem, cov pa roj carbon nplaum thiab cov pore, thiab cov porosity tuaj yeem suav tau los ntawm kev sib npaug hauv qab no.
Ntawm lawv, qhov nruab nrab ntom ntom ntawm txheej yog: lithium roj teeb electrode yog ib hom hmoov hmoov txheej ntawm txheej, vim hais tias cov hmoov particle nto ntxhib, cov duab tsis zoo, thaum sib sau ua ke, cov khoom ntawm cov khoom thiab cov khoom, thiab qee cov khoom nws tus kheej muaj cov kab nrib pleb thiab qhov hws, Yog li cov hmoov ntim nrog rau cov hmoov ntim, qhov pores ntawm cov hmoov nplej thiab cov khoom, yog li ntawd, cov khoom sib xws ntawm electrode txheej ntom ntom thiab porosity sawv cev. Qhov ceev ntawm cov hmoov hais yog hais txog qhov loj ntawm cov hmoov hauv ib chav tsev ntim. Raws li lub ntim ntawm cov hmoov, nws muab faib ua peb hom: qhov tseeb ceev, particle ceev thiab tsub zuj zuj ceev. Qhov ntau yam ntom ntom tau txhais raws li hauv qab no:
- Qhov ntom ntom tiag tiag yog hais txog qhov ntom ntom tau los ntawm kev faib cov hmoov loj los ntawm qhov ntim (lub ntim tiag) tsis suav nrog qhov sib txawv hauv thiab sab nraud ntawm cov khoom. Ntawd yog, qhov ntom ntawm qhov teeb meem nws tus kheej tau txais tom qab tsis suav nrog qhov ntim ntawm tag nrho cov voids.
- Particle ntom yog hais txog qhov ntom ntawm cov khoom tau los ntawm kev faib cov hmoov loj faib los ntawm cov khoom ntim nrog rau lub qhov qhib thiab lub qhov kaw. Ntawd yog, qhov sib txawv ntawm cov khoom, tab sis tsis yog cov pores zoo hauv cov khoom, qhov ntom ntawm cov khoom lawv tus kheej.
- Accumululation density, uas yog, txheej ntom ntom, yog hais txog qhov ntom ntom tau los ntawm cov hmoov loj muab faib los ntawm qhov ntim ntawm txheej txheej tsim los ntawm cov hmoov. Lub ntim siv suav nrog cov pores ntawm cov khoom lawv tus kheej thiab cov voids ntawm cov khoom.
Rau tib cov hmoov, qhov tseeb ntom> particle ntom> ntim ntom. Lub porosity ntawm cov hmoov yog qhov piv ntawm cov pores nyob rau hauv cov hmoov particle txheej, uas yog, qhov piv ntawm lub ntim ntawm cov void ntawm cov hmoov hais thiab cov pores ntawm cov hais mus rau tag nrho cov ntim ntawm txheej, uas yog feem ntau qhia. raws li feem pua. Lub porosity ntawm hmoov yog ib qho cuab yeej muaj feem xyuam rau particle morphology, deg lub xeev, particle loj thiab particle loj tis. Nws cov porosity ncaj qha cuam tshuam rau kev nkag mus ntawm electrolyte thiab lithium ion kis tau tus mob. Feem ntau, qhov loj dua qhov porosity, qhov yooj yim ntawm electrolyte infiltration, thiab qhov ceev ntawm lithium ion kis tau tus mob. Yog li ntawd, hauv kev tsim cov roj teeb lithium, qee zaum los txiav txim siab qhov porosity, feem ntau siv mercury siab txoj kev, roj adsorption txoj kev, thiab lwm yam tuaj yeem tau txais los ntawm kev siv cov ntsuas qhov ntom ntom. Lub porosity kuj tuaj yeem muaj qhov cuam tshuam sib txawv thaum siv qhov sib txawv rau kev suav. Thaum qhov ceev ntawm qhov porosity ntawm cov khoom muaj sia nyob, tus neeg sawv cev conductive thiab cov ntawv khi yog xam los ntawm qhov tseeb qhov ceev, cov porosity xam suav nrog qhov sib txawv ntawm cov khoom thiab qhov sib txawv hauv cov khoom. Thaum lub porosity ntawm cov khoom muaj sia nyob, tus neeg sawv cev ntawm cov khoom siv hluav taws xob thiab cov binder yog xam los ntawm qhov ntom ntom, cov porosity xam suav nrog qhov sib txawv ntawm cov khoom, tab sis tsis yog qhov sib txawv hauv cov khoom. Yog li ntawd, qhov pore loj ntawm lithium roj teeb electrode daim ntawv tseem muaj ntau qhov sib txawv, feem ntau qhov sib txawv ntawm cov khoom yog nyob rau hauv micron nplai loj, thaum qhov sib txawv hauv cov khoom yog nyob rau hauv nanometer rau sub-submicron scale. Nyob rau hauv porous electrodes, kev sib raug zoo ntawm kev thauj khoom xws li zoo diffusivity thiab conductivity yuav qhia tau los ntawm cov nram qab no kab zauv:
Qhov twg D0 sawv cev rau qhov intrinsic diffusion (conduction) tus nqi ntawm cov khoom nws tus kheej, ε yog qhov ntim feem ntawm cov theem sib thooj, thiab τ yog lub voj voog curvature ntawm cov theem sib thooj. Hauv cov qauv macroscopic homogeneous, Bruggeman kev sib raug zoo feem ntau yog siv, noj cov coefficient ɑ = 1.5 los kwv yees qhov txiaj ntsig zoo ntawm cov hluav taws xob ntxeem tau.
Cov electrolyte tau ntim rau hauv cov pores ntawm cov porosity electrodes, nyob rau hauv uas cov lithium ions yog ua los ntawm electrolyte, thiab cov yam ntxwv conduction ntawm lithium ions yog ze ze rau lub porosity. Qhov loj dua qhov porosity, qhov ntau dua qhov ntim feem ntawm cov theem electrolyte, thiab ntau dua qhov ua tau zoo ntawm lithium ions. Nyob rau hauv daim ntawv zoo electrode, electrons raug xa mus los ntawm cov pa roj carbon nplaum theem, qhov ntim feem ntawm cov pa roj carbon nplaum theem thiab qhov kev taug kev ntawm cov pa roj carbon nplaum theem ncaj qha txiav txim siab qhov ua tau zoo ntawm electrons.
Cov porosity thiab qhov ntim feem ntawm cov pa roj carbon adhesive theem yog qhov tsis sib xws, thiab qhov porosity loj inevitably ua rau lub ntim feem ntawm cov pa nplaum theem, yog li ntawd, cov khoom siv hluav taws xob zoo ntawm lithium ions thiab electrons kuj tsis sib xws, raws li qhia hauv daim duab 2. Raws li qhov porosity txo, lithium ion zoo conductivity txo thaum lub electron zoo conductivity nce. Yuav ua li cas sib npaug ntawm ob kuj tseem ceeb heev hauv kev tsim electrode.
Daim duab 2 Schematic daim duab ntawm porosity thiab lithium ion thiab electron conductivity
2. Hom thiab nrhiav kom tau tus ncej tsis xws luag
Tam sim no, nyob rau hauv cov txheej txheem ntawm lub roj teeb ncej npaj, ntau thiab ntau hauv internet nrhiav yees tau txais yuav, thiaj li yuav zoo txheeb xyuas cov khoom tsis xws luag, tshem tawm cov khoom puas, thiab raws sij hawm tawm tswv yim rau cov kab ntau lawm, tsis siv neeg los yog phau ntawv hloov kho rau cov khoom. txheej txheem, kom txo tau qhov tsis xws luag.
Cov thev naus laus zis tshawb nrhiav hauv online feem ntau siv hauv cov ntawv tsim cov ntawv suav nrog kev tshawb nrhiav cov yam ntxwv slurry, cov ntawv txheeb xyuas cov ntawv zoo, nrhiav kom pom qhov loj thiab lwm yam, Piv txwv li: (1) cov viscosity meter hauv online yog ncaj qha ntsia rau hauv cov txheej ntim cia kom pom cov rheological cov yam ntxwv ntawm cov slurry nyob rau hauv lub sij hawm ntawm lub sij hawm, kuaj lub stability ntawm lub slurry; (2) Siv X-ray lossis β -ray hauv txheej txheej txheej txheej, Nws qhov ntsuas siab raug, Tab sis cov hluav taws xob loj, cov khoom siv siab thiab cov teeb meem txij nkawm; (3) Laser online thickness ntsuas tshuab yog siv los ntsuas qhov tuab ntawm daim ntawv ncej, qhov ntsuas qhov tseeb tuaj yeem ncav cuag ± 1. 0 μ m, Nws tuaj yeem tso saib qhov hloov pauv ntawm kev ntsuas tuab thiab tuab hauv lub sijhawm, Ua kom cov ntaub ntawv traceability thiab tsom xam; (4) CCD pom kev thev naus laus zis, Qhov ntawd yog, kab array CCD yog siv los luam theej cov khoom ntsuas, kev ua cov duab tiag tiag thiab kev tshuaj xyuas ntawm pawg tsis raug, Paub txog qhov tsis muaj kev puas tsuaj online nrhiav pom ntawm cov ncej ntawm qhov tsis xws luag.
Raws li lub cuab yeej rau kev tswj kom zoo, kev sim tshuab hauv online tseem yog qhov tseem ceeb kom nkag siab txog kev sib raug zoo ntawm qhov tsis xws luag thiab kev ua haujlwm ntawm roj teeb, thiaj li txiav txim siab qhov tsim nyog / tsis tsim nyog rau cov khoom lag luam ib nrab.
Nyob rau hauv qhov kawg, txoj kev tshiab ntawm nto defect detection technology ntawm lithium-ion roj teeb, infrared thermal imaging technology thiab cov kev sib raug zoo ntawm cov txawv tsis xws luag thiab electrochemical kev ua tau zoo yog luv luv qhia.consult D. Mohanty Ib txoj kev kawm zoo los ntawm Mohanty li al.
(1) Kev tsis xws luag ntawm tus ncej ncej
Daim duab 3 qhia txog qhov tsis xws luag nyob rau saum npoo ntawm lithium ion roj teeb electrode, nrog cov duab kho qhov muag ntawm sab laug thiab cov duab ntes los ntawm thermal imager ntawm sab xis.
Daim duab 3 Feem ntau qhov tsis xws luag ntawm daim ntawv ncej: (a, b) bulge hnab ntawv / aggregate; (c, d) poob khoom / pinhole; (e, f) hlau txawv teb chaws lub cev; (g, h) txheej txheej
(A, b) tsa cov pob txha / sib sau ua ke, qhov tsis xws luag tuaj yeem tshwm sim yog tias cov slurry sib npaug sib npaug los yog txheej txheej ceev tsis ruaj khov. Kev sib sau ua ke ntawm cov nplaum thiab cov pa roj carbon dub cov neeg ua haujlwm ua rau cov ntsiab lus qis ntawm cov khoom xyaw nquag thiab lub teeb yuag ntawm cov ntsiav tshuaj polar.
(c, d) poob / pinhole, cov chaw tsis zoo no tsis yog coated thiab feem ntau yog ua los ntawm npuas hauv slurry. Lawv txo tus nqi ntawm cov khoom nquag thiab nthuav tawm cov khoom siv rau cov khoom siv electrolyte, yog li txo cov peev txheej electrochemical.
(E, f) hlau txawv teb chaws lub cev, slurry los yog hlau txawv teb chaws lub cev qhia nyob rau hauv cov khoom thiab ib puag ncig, thiab hlau txawv teb chaws lub cev tuaj yeem ua rau muaj kev puas tsuaj loj rau cov roj teeb lithium. Cov hlau loj loj ncaj qha cuam tshuam lub diaphragm, ua rau luv luv ntawm qhov zoo thiab tsis zoo electrodes, uas yog lub cev luv luv. Tsis tas li ntawd, thaum cov hlau txawv teb chaws lub cev sib xyaw rau hauv qhov zoo electrode, qhov zoo muaj peev xwm nce tom qab them nyiaj, cov hlau daws teeb meem, kis los ntawm electrolyte, thiab tom qab ntawd los nag rau ntawm qhov tsis zoo, thiab thaum kawg puncture lub diaphragm, tsim ib qho luv luv Circuit Court, uas yog chemical dissolution luv luv Circuit Court. Feem ntau cov hlau txawv teb chaws lub cev nyob rau hauv lub chaw tsim khoom roj teeb yog Fe, Cu, Zn, Al, Sn, SUS, thiab lwm yam.
(g, h) txheej txheej tsis sib xws, xws li cov slurry sib tov tsis txaus, cov particle fineness yog ib qho yooj yim kom pom kab txaij thaum lub particle loj, ua rau cov txheej tsis sib xws, uas yuav cuam tshuam rau qhov sib xws ntawm cov roj teeb muaj peev xwm, thiab txawm tias tshwm sim tag nrho. tsis muaj txheej kab txaij, muaj kev cuam tshuam rau lub peev xwm thiab kev nyab xeeb.
(2) Ncej nti nto defect detection thev naus laus zis Infrared (IR) thermal imaging technology yog siv los kuaj xyuas qhov tsis xws luag ntawm cov electrodes qhuav uas tuaj yeem ua rau kev ua haujlwm ntawm lithium-ion roj teeb. Thaum kuaj pom hauv online, yog tias kuaj pom qhov tsis xws ntawm electrode lossis cov pa phem, kos rau ntawm daim ntawv ncej, tshem tawm nws hauv cov txheej txheem tom ntej, thiab tawm tswv yim rau cov kab ntau lawm, thiab kho cov txheej txheem hauv lub sijhawm kom tshem tawm qhov tsis xws luag. Infrared ray yog ib hom electromagnetic yoj uas muaj tib yam li xov tooj cua nthwv dej thiab pom lub teeb. Ib qho khoom siv hluav taws xob tshwj xeeb yog siv los hloov qhov kub thiab txias ntawm qhov chaw ntawm ib qho khoom mus rau hauv cov duab pom ntawm tib neeg lub qhov muag, thiab los tso saib qhov kub ntawm qhov chaw ntawm cov khoom hauv cov xim sib txawv hu ua infrared thermal imaging technology. Cov khoom siv hluav taws xob no hu ua infrared thermal imager. Txhua yam khoom saum toj kawg nkaus xoom (-273 ℃) emit infrared tawg.
Raws li pom nyob rau hauv daim duab 4, lub infrared thermal approximator (IR lub koob yees duab) siv lub infrared detector thiab lub hom phiaj kho qhov muag pom zoo kom txais lub infrared hluav taws xob hluav taws xob faib qauv ntawm lub hom phiaj ntsuas khoom thiab muaj kev cuam tshuam nws nyob rau hauv lub photosensitive caij ntawm lub infrared detector kom tau lub infrared thermal duab, uas sib haum mus rau thermal faib teb rau ntawm qhov chaw ntawm cov khoom. Thaum muaj qhov tsis xws luag ntawm qhov chaw ntawm qhov khoom, qhov kub hloov pauv hauv cheeb tsam. Yog li ntawd, cov cuab yeej no tseem tuaj yeem siv los txheeb xyuas qhov tsis xws ntawm qhov chaw ntawm cov khoom, tshwj xeeb tshaj yog tsim rau qee qhov tsis xws luag uas tsis tuaj yeem paub qhov txawv ntawm qhov ntsuas qhov muag pom. Thaum lub tshuab ziab khaub ncaws ntawm lithium ion roj teeb tau pom hauv online, lub tshuab hluav taws xob electrode yog thawj zaug irradiated los ntawm lub teeb, qhov kub thiab txias ntawm qhov chaw hloov, thiab tom qab ntawd qhov kub thiab txias tau kuaj pom nrog lub thermal imager. Daim duab faib hluav taws xob yog pom tau, thiab cov duab tau ua tiav thiab tshuaj xyuas hauv lub sijhawm tiag tiag txhawm rau txheeb xyuas qhov tsis xws luag ntawm qhov chaw thiab cim lawv raws sijhawm.D. Mohanty Txoj kev tshawb no tau teeb tsa lub thermal imager ntawm lub qhov hluav taws xob ntawm lub coater kom qhuav qhov cub kom pom qhov kub thiab txias ntawm daim ntawv electrode.
Daim duab 5 (a) yog daim ntawv qhia qhov kub thiab txias ntawm txheej txheej ntawm NMC daim ntawv zoo ncej kuaj pom los ntawm thermal imager, uas muaj qhov tsis zoo me me uas tsis tuaj yeem paub qhov txawv ntawm qhov muag liab qab. Qhov kub faib nkhaus sib haum mus rau txoj kev ntu yog qhia nyob rau hauv inset, nrog rau qhov kub thiab txias ntawm qhov tsis xws luag. Nyob rau hauv daim duab 5 (b), qhov kub thiab txias nce hauv zos nyob rau hauv lub thawv sib thooj, sib xws rau qhov tsis xws luag ntawm tus ncej ncej. FIG. 6 yog daim duab qhia txog qhov kub thiab txias ntawm daim ntawv tsis zoo electrode qhia txog qhov muaj qhov tsis xws luag, qhov chaw siab tshaj ntawm qhov kub thiab txias nce sib haum mus rau cov npuas los yog aggregate, thiab thaj tsam ntawm qhov kub ntawm qhov txo qis sib haum mus rau lub pinhole los yog poob.
Daim duab 5 Kub faib ntawm qhov zoo electrode daim ntawv nto
Daim duab 6 Kub faib ntawm qhov tsis zoo electrode nto
Nws tuaj yeem pom tau tias qhov ntsuas qhov ntsuas kub ntawm qhov ntsuas kub yog qhov zoo ntawm cov ntawv txheeb xyuas qhov tsis xws luag, uas tuaj yeem siv rau kev tswj xyuas cov ntawv zoo.3. Qhov cuam tshuam ntawm cov ntawv ncej saum npoo tsis xws luag ntawm lub roj teeb kev ua haujlwm
(1) Kev cuam tshuam rau lub roj teeb ntau lub peev xwm thiab Coulomb efficiency
Daim duab 7 qhia txog qhov cuam tshuam ntawm qhov sib sau ua ke thiab pinhole ntawm lub roj teeb ntau lub peev xwm thiab coulen efficiency. Lub aggregate tuaj yeem txhim kho lub peev xwm roj teeb, tab sis txo cov coulen efficiency. Lub pinhole txo cov roj teeb muaj peev xwm thiab Kulun efficiency, thiab Kulun efficiency txo qis heev ntawm tus nqi siab.
Daim duab 7 cathode aggregate thiab pinhole cuam tshuam rau lub roj teeb muaj peev xwm thiab qhov ua tau zoo ntawm daim duab 8 yog txheej txheej tsis sib xws, thiab hlau txawv teb chaws lub cev Co thiab Al ntawm lub roj teeb muaj peev xwm thiab cov txiaj ntsig ntawm kev ua haujlwm nkhaus, cov txheej tsis sib xws txo cov roj teeb muaj peev xwm 10% - 20%, tab sis tag nrho cov roj teeb muaj peev xwm txo qis los ntawm 60%, qhov no qhia tau hais tias qhov muaj sia nyob hauv cov polar piece tau txo qis. Hlau Co txawv teb chaws lub cev txo lub peev xwm thiab Coulomb efficiency, txawm nyob rau hauv 2C thiab 5C siab magnification, tsis muaj peev xwm ntawm tag nrho cov, uas tej zaum yuav yog vim lub tsim ntawm hlau Co nyob rau hauv lub electrochemical tshuaj ntawm lithium thiab lithium embedded, los yog tej zaum nws yuav yog cov hlau hais. thaiv lub diaphragm pore ua rau micro short circuit.
Daim duab 8 Cov teebmeem ntawm qhov zoo electrode tsis sib xws txheej thiab hlau txawv teb chaws lub cev Co thiab Al ntawm cov roj teeb muaj peev xwm thiab coulen efficiency
Cov ntsiab lus ntawm cathode sheet defects: Cov ates nyob rau hauv cathode daim ntawv txheej txo cov Coulomb efficiency ntawm lub roj teeb. Lub pinhole ntawm cov txheej txheej zoo txo cov Coulomb efficiency, ua rau cov neeg ua haujlwm tsis zoo, tshwj xeeb tshaj yog nyob rau qhov ceev tam sim no. Cov txheej txheej heterogeneous tau pom qhov ua haujlwm tsis zoo. Cov pa phem hlau tuaj yeem ua rau micro-short circuits, thiab yog li ntawd yuav txo tau lub roj teeb muaj peev xwm.
Daim duab 9 qhia txog qhov cuam tshuam ntawm qhov tsis zoo ntawm cov ntawv ci tawm ntawm lub peev xwm sib npaug thiab Kulun efficiency ntawm lub roj teeb. Thaum cov leakage tshwm sim ntawm qhov tsis zoo electrode, lub peev xwm ntawm lub roj teeb tau txo qis, tab sis lub peev xwm gram tsis pom tseeb, thiab qhov cuam tshuam ntawm Kulun efficiency tsis tseem ceeb.
Daim duab 9 Kev cuam tshuam ntawm qhov tsis zoo electrode leakage foil strip ntawm lub roj teeb ntau lub peev xwm thiab Kulun efficiency (2) Kev cuam tshuam ntawm lub roj teeb ntau lub voj voog kev ua tau zoo Daim duab 10 yog qhov tshwm sim ntawm kev cuam tshuam ntawm electrode defect ntawm lub roj teeb multiplier voj voog. Cov txiaj ntsig cuam tshuam tau sau tseg raws li hauv qab no:
Egregation: ntawm 2C, lub peev xwm txij nkawm ntawm 200 cycles yog 70% thiab cov roj teeb tsis zoo yog 12%, thaum nyob rau hauv 5C voj voog, lub peev xwm tu tus nqi ntawm 200 cycles yog 50% thiab cov roj teeb tsis zoo yog 14%.
Koob: lub peev xwm attenuation yog qhov pom tseeb, tab sis tsis muaj qhov tsis sib haum xeeb attenuation yog ceev, thiab lub peev xwm tu tus nqi ntawm 200 cycles 2C thiab 5C yog 47% thiab 40%, feem.
Hlau txawv teb chaws lub cev: lub peev xwm ntawm hlau Co txawv teb chaws lub cev yog yuav luag 0 tom qab ob peb lub voj voog, thiab 5C lub voj voog muaj peev xwm ntawm cov hlau txawv teb chaws Al foil txo qis.
Leak strip: Rau tib qhov chaw xau, lub roj teeb muaj peev xwm ntawm ntau cov kab txaij me me txo qis dua cov kab txaij loj (47% rau 200 cycles hauv 5C) (7% rau 200 cycles hauv 5C). Qhov no qhia tias qhov loj ntawm cov kab txaij, qhov cuam tshuam ntau dua rau lub voj voog roj teeb.
Daim duab 10 Qhov cuam tshuam ntawm daim ntawv electrode defects ntawm lub voj voog ntawm tes
Ref.: [1] Kev ntsuam xyuas tsis muaj kev puas tsuaj ntawm slot-die-coated lithium secondary batteryelectrodes los ntawm in-line laser caliper thiab IR thermography method [J].ANALYTICALMETHODS.2014, 6(3): 674-683.[2]Effect of electrode manufacturing defects on electrochemical performance oflithium-ion batteries: Cognizance of the battery failure sources [J].Journal of Power Sources.2016, 312: 70-79.
