Txij li thaum cov roj teeb lithium-ion nkag mus rau hauv kev ua lag luam, lawv tau siv dav vim lawv qhov zoo ntawm lub neej ntev, muaj peev xwm loj, thiab tsis muaj kev nco. Kev siv cov roj ntsha lithium-ion kub tsawg muaj teeb meem xws li tsis muaj peev xwm, kev ua haujlwm hnyav, kev ua haujlwm tsis zoo, kev tso tawm lithium pom tseeb, thiab kev rho tawm lithium tsis sib npaug. Txawm li cas los xij, nrog kev nthuav dav ntawm daim ntawv thov kev lag luam, cov kev txwv los ntawm kev ua haujlwm tsis zoo ntawm cov roj teeb lithium-ion tau dhau los ua pom tseeb.

Raws li cov lus ceeb toom, lub peev xwm tso tawm ntawm lithium-ion roj teeb ntawm -20 ° C tsuas yog kwv yees li 31.5% ntawm qhov kub ntawm chav tsev. Kev ua haujlwm kub ntawm cov roj teeb lithium-ion ib txwm nyob nruab nrab ntawm -20 txog +55 ° C. Txawm li cas los xij, hauv kev lag luam aerospace, kev lag luam tub rog, tsheb hluav taws xob, thiab lwm yam, lub roj teeb yuav tsum ua haujlwm ib txwm ntawm -40 ° C. Yog li ntawd, nws yog ib qho tseem ceeb heev los txhim kho qhov kub thiab txias ntawm Li-ion roj teeb.

Cov xwm txheej txwv qhov ntsuas kub qis ntawm Li-ion roj teeb

Nyob rau hauv ib puag ncig uas tsis muaj qhov kub thiab txias, viscosity ntawm cov electrolyte nce thiab txawm tias ib nrab solidifies, ua rau txo qis hauv cov roj teeb lithium-ion.

Kev sib raug zoo ntawm cov electrolyte thiab cov electrode tsis zoo thiab cov khoom sib cais ua rau tsis zoo nyob rau hauv ib puag ncig uas tsis tshua muaj kub.

Qhov tsis zoo electrode ntawm lithium-ion roj teeb muaj qhov hnyav lithium nag lossis daus nyob rau hauv ib puag ncig uas tsis muaj qhov kub thiab txias, thiab cov nag lossis daus ntawm cov hlau lithium reacts nrog cov electrolyte, thiab nws cov khoom tso tawm ua rau muaj kev nce hauv thickness ntawm cov khoom-electrolyte interface (SEI).

Nyob rau hauv qhov kub thiab txias ib puag ncig, lub diffusion system ntawm Li-ion roj teeb nyob rau hauv cov khoom nquag txo, thiab tus nqi hloov pauv tsis kam (Rct) nce ntau.

Kev sib tham txog yam cuam tshuam rau qhov ntsuas kub qis ntawm Li-ion roj teeb

Cov kws tshaj lij lub tswv yim 1: Cov electrolyte muaj qhov cuam tshuam loj tshaj plaws ntawm qhov kub thiab txias ntawm lithium-ion roj teeb, thiab cov khoom muaj pes tsawg leeg thiab physicochemical ntawm cov electrolyte muaj qhov cuam tshuam tseem ceeb rau kev ua haujlwm kub ntawm lub roj teeb. Cov teeb meem tshwm sim los ntawm lub voj voog ntawm lub roj teeb ntawm qhov kub qis yog: lub viscosity ntawm electrolyte yuav nce, thiab ion conduction ceev yuav qeeb, ua rau lub mismatch ntawm electron migration ceev ntawm sab nraud Circuit Court, yog li ntawd lub roj teeb yog polarized heev, thiab tus nqi thiab tso tawm muaj peev xwm txo qis heev. Tshwj xeeb tshaj yog thaum them nyiaj ntawm qhov kub thiab txias, lithium ions yooj yim tsim lithium dendrites rau ntawm qhov chaw ntawm cov electrode tsis zoo, ua rau lub roj teeb tsis ua haujlwm.

Qhov ntsuas kub qis ntawm cov electrolyte yog ze ze rau qhov loj ntawm cov conductivity ntawm electrolyte nws tus kheej. Cov electrolyte nrog high conductivity kis ions sai sai thiab muaj peev xwm siv tau ntau dua ntawm qhov kub thiab txias. Qhov ntau dissociated cov lithium ntsev nyob rau hauv cov electrolyte, qhov ntau ntawm cov migrations thiab ntau dua cov conductivity. Qhov siab dua cov hluav taws xob conductivity, qhov ceev ntawm ion conduction tus nqi, qhov polarization tsawg dua, thiab qhov ua tau zoo ntawm lub roj teeb ntawm qhov kub thiab txias. Yog li ntawd, kev siv hluav taws xob ntau dua yog qhov tsim nyog kom ua tiav qhov kev ua tau zoo ntawm qhov kub thiab txias ntawm lithium-ion roj teeb.

Lub conductivity ntawm cov electrolyte muaj feem xyuam rau cov muaj pes tsawg leeg ntawm cov electrolyte, thiab txo cov viscosity ntawm cov kuab tshuaj yog ib txoj hauv kev los txhim kho cov conductivity ntawm electrolyte. Qhov zoo ntawm cov kuab tshuaj ntawm qhov kub thiab txias yog qhov lav ntawm kev thauj mus los ntawm ion, thiab cov khoom siv electrolyte zaj duab xis tsim los ntawm electrolyte ntawm qhov tsis zoo electrode ntawm qhov kub thiab txias kuj yog tus yuam sij rau cuam tshuam cov kev coj ntawm lithium ions, thiab RSEI yog lub ntsiab impedance. ntawm lithium ion roj teeb nyob rau hauv qhov kub thiab txias ib puag ncig.

Cov kws tshaj lij 2: Qhov tseem ceeb tshaj plaws txwv qhov ntsuas kub qis ntawm lithium-ion roj teeb yog qhov ua kom muaj zog Li + diffusion tsis kam ntawm qhov kub qis, tsis yog SEI zaj duab xis.

Tsawg kub cov khoom ntawm cathode cov ntaub ntawv rau lithium ion roj teeb

1. Tsawg kub khoom ntawm cov ntaub ntawv cathode txheej

Cov txheej txheem txheej tsis tsuas yog muaj qhov sib piv tsis tau zoo ntawm ib-dimensional lithium ion diffusion raws, tab sis kuj muaj cov qauv kev ruaj ntseg ntawm peb-dimensional channels. Nws yog cov khoom lag luam cathode ntxov tshaj plaws rau cov roj teeb lithium ion. Nws cov khoom sawv cev yog LiCoO2, Li(Co1-xNix)O2 thiab Li(Ni, Co, Mn)O2 thiab lwm yam.

Xie Xiaohua et al. coj LiCoO2 / MCMB ua cov khoom tshawb fawb thiab kuaj nws cov yam ntxwv qis-kub-tso tawm.

Cov txiaj ntsig tau pom tias nrog qhov txo qis ntawm qhov kub thiab txias, qhov tso tawm platform poob ntawm 3.762V (0 ° C) txog 3.207V (-30 ° C); tag nrho cov roj teeb muaj peev xwm kuj txo qis los ntawm 78.98mA·h (0°C) txog 68.55mA·h (–30°C).

2. Tsawg-kub yam ntxwv ntawm spinel-structured cathode cov ntaub ntawv

Cov qauv spinel LiMn2O4 cathode cov khoom muaj qhov zoo ntawm tus nqi qis thiab tsis muaj tshuaj lom vim nws tsis muaj cov khoom Co.

Txawm li cas los xij, qhov sib txawv ntawm valence ntawm Mn thiab Jahn-Teller cuam tshuam ntawm Mn3+ ua rau muaj kev tsis sib haum xeeb thiab tsis zoo ntawm cov khoom siv no.

Peng Zhengshun et al. taw qhia tias kev npaj sib txawv muaj kev cuam tshuam zoo rau kev ua haujlwm ntawm electrochemical ntawm LiMn2O4 cathode cov ntaub ntawv. Noj Rct ua piv txwv: Rct ntawm LiMn2O4 synthesized los ntawm qhov kub thiab txias-theem txheej txheem yog siab dua li ntawm sol-gel txoj kev, thiab qhov tshwm sim no tsis cuam tshuam los ntawm lithium ions. Lub diffusion coefficient kuj tshwm sim. Yog vim li cas yog qhov sib txawv ntawm cov txheej txheem synthesis muaj kev cuam tshuam zoo rau cov crystallinity thiab morphology ntawm cov khoom.

3. Tsawg kub yam ntxwv ntawm cov khoom siv cathode ntawm phosphate system

Vim nws zoo heev ntim stability thiab kev nyab xeeb, LiFePO4, nrog rau cov ntaub ntawv ternary, tau dhau los ua lub cev tseem ceeb ntawm cov khoom siv roj teeb cathode tam sim no. Kev ua haujlwm tsis zoo ntawm lithium hlau phosphate feem ntau yog vim nws cov khoom siv nws tus kheej yog ib qho insulator, nrog cov hluav taws xob tsis zoo, tsis zoo lithium ion diffusivity, thiab tsis zoo conductivity ntawm qhov kub thiab txias, uas ua rau muaj kev tiv thaiv sab hauv ntawm lub roj teeb, uas cuam tshuam zoo heev. polarization, thiab lub roj teeb them thiab tawm yog hindered. Yog li ntawd, qhov kub thiab txias Performance tsis zoo tagnrho.

Thaum kawm txog tus cwj pwm coj tawm ntawm LiFePO4 ntawm qhov kub thiab txias, Gu Yijie li al. pom tias nws cov coulombic efficiency poob ntawm 100% ntawm 55 ° C mus rau 96% ntawm 0 ° C thiab 64% ntawm -20 ° C, feem; Qhov kev tawm hluav taws xob txo qis ntawm 3.11V ntawm 55 ° C. Txo rau 2.62V ntawm -20 ° C.

Xing et al. Hloov kho LiFePO4 nrog nanocarbon thiab pom tias tom qab ntxiv nanocarbon conductive tus neeg sawv cev, electrochemical kev ua tau zoo ntawm LiFePO4 tsis tshua muaj siab rau qhov kub thiab txias, thiab kev ua haujlwm kub tsawg tau txhim kho; Qhov hluav taws xob tawm ntawm kev hloov pauv LiFePO4 tau nce los ntawm 3.40 ntawm 25 ° CV poob rau 3.09V ntawm -25 ° C, txo qis tsuas yog 9.12%; thiab nws cov cell efficiency ntawm -25 ° C yog 57.3%, uas yog siab tshaj 53.4% ​​​​tsis muaj nano-carbon conductive tus neeg saib xyuas.

Tsis ntev los no, LiMnPO4 tau txais kev txaus siab ntau. Txoj kev tshawb nrhiav pom tias LiMnPO4 muaj qhov zoo ntawm qhov muaj peev xwm siab (4.1V), tsis muaj kuab paug, tus nqi qis, thiab muaj peev xwm loj (170mAh / g). Txawm li cas los xij, vim qhov qis ionic conductivity ntawm LiMnPO4 dua li LiFePO4, Fe feem ntau siv los hloov Mn ib nrab los ua LiMn0.8Fe0.2PO4 cov khoom siv hauv kev xyaum.

Tsawg kub khoom ntawm cov khoom siv anode rau lithium ion roj teeb

Piv nrog rau cov khoom siv hluav taws xob zoo, qhov kub tsis zoo ntawm cov khoom siv hluav taws xob tsis zoo ntawm lithium ion roj teeb yog qhov hnyav dua, feem ntau yog vim li cas hauv qab no:

Thaum them nyiaj thiab tso tawm ntawm qhov kub thiab txias siab, lub roj teeb yog polarized tiag tiag, thiab ntau cov hlau lithium tso rau ntawm qhov chaw ntawm qhov tsis zoo electrode, thiab cov tshuaj tiv thaiv ntawm cov hlau lithium thiab electrolyte feem ntau tsis muaj conductivity;

Los ntawm qhov ntsuas kub ntawm qhov pom, cov electrolyte muaj ntau pawg polar xws li CO thiab CN, uas tuaj yeem cuam tshuam nrog cov khoom siv hluav taws xob tsis zoo, thiab tsim SEI zaj duab xis yog qhov cuam tshuam rau qhov kub thiab txias;

Cov pa roj carbon tsis zoo electrode yog nyuaj rau intercalate lithium ntawm qhov kub thiab txias, thiab muaj asymmetric nqi thiab tawm.

daim duab

Kev tshawb fawb ntawm Tsawg Kub Electrolyte

Cov electrolyte ua lub luag haujlwm ntawm kev thauj Li + hauv cov roj teeb lithium-ion, thiab nws cov ionic conductivity thiab SEI zaj duab xis-tsim cov khoom muaj kev cuam tshuam loj rau kev ua haujlwm kub ntawm lub roj teeb. Muaj peb lub ntsiab lus qhia rau kev txiav txim siab qhov zoo thiab qhov tsis zoo ntawm qhov kub thiab txias electrolytes: ionic conductivity, electrochemical qhov rais thiab electrode reactivity. Cov theem ntawm peb qhov ntsuas no nyob ntawm qhov loj ntawm nws cov khoom siv: hnyav, electrolyte (lithium ntsev), thiab additives. Yog li ntawd, kev tshawb fawb txog kev ua haujlwm ntawm qhov kub thiab txias ntawm txhua qhov ntawm cov electrolyte yog qhov tseem ceeb rau kev nkag siab thiab kev txhim kho qhov kub thiab txias ntawm cov roj teeb.

Piv nrog cov saw carbonates, qhov kub tsis tshua muaj tus yam ntxwv ntawm EC-raws li electrolytes, cyclic carbonates muaj cov qauv compact, loj ua yeeb yam, thiab ntau dua melting point thiab viscosity. Txawm li cas los xij, qhov loj polarity coj los ntawm lub nplhaib qauv ua rau nws feem ntau muaj qhov loj dielectric tas li. Qhov loj dielectric tas li, siab ionic conductivity, thiab zoo heev film-forming zog ntawm EC cov kuab tshuaj zoo tiv thaiv kev sib koom ua ke ntawm cov kuab tshuaj molecules, ua rau lawv indispensable. Yog li ntawd, feem ntau ntawm cov khoom siv hluav taws xob qis qis feem ntau yog raws li EC, thiab tom qab ntawd sib xyaw me me molecule hnyav nrog cov ntsiab lus melting tsawg.

Lithium ntsev yog ib qho tseem ceeb ntawm electrolyte. Lithium ntsev hauv electrolyte tuaj yeem tsis tsuas yog txhim kho cov ionic conductivity ntawm cov tshuaj, tab sis kuj txo qhov diffusion deb ntawm Li + hauv cov tshuaj. Feem ntau, qhov ntau dua qhov concentration ntawm Li + hauv cov tshuaj, qhov ntau dua qhov ionic conductivity. Txawm li cas los xij, qhov concentration ntawm lithium ions hauv electrolyte tsis yog linearly cuam tshuam nrog cov concentration ntawm lithium ntsev, tab sis yog parabolic. Qhov no yog vim qhov concentration ntawm lithium ions nyob rau hauv cov kuab tshuaj nyob ntawm lub zog ntawm dissociation thiab koom haum ntawm lithium ntsev nyob rau hauv cov kuab tshuaj.

Kev tshawb fawb ntawm Tsawg Kub Electrolyte

Ntxiv rau qhov muaj pes tsawg leeg ntawm lub roj teeb nws tus kheej, cov txheej txheem txheej txheem hauv kev ua haujlwm tiag tiag kuj tseem yuav cuam tshuam zoo rau kev ua haujlwm ntawm lub roj teeb.
(1) Cov txheej txheem npaj. Yaqub et al. tau kawm txog cov nyhuv ntawm electrode load thiab txheej thickness ntawm qhov kub tsis tshua muaj kev ua tau zoo ntawm LiNi0.6Co0.2Mn0.2O2 / Graphite roj teeb thiab pom tias nyob rau hauv cov nqe lus ntawm lub peev xwm tuav, lub me me electrode load thiab lub thinner txheej txheej, qhov zoo dua qhov tsawg. kub ua haujlwm. .

(2) Lub xeev ntawm kev them nqi thiab tso tawm. Petzl et al. tau kawm txog cov txiaj ntsig ntawm qhov ntsuas kub qis-tso tawm lub xeev ntawm lub roj teeb lub neej, thiab pom tias thaum qhov tob ntawm qhov paug tawm loj, nws yuav ua rau muaj peev xwm ntau dua thiab txo lub voj voog lub neej.

(3) Lwm yam. Qhov chaw saum npoo, qhov pore loj, electrode ntom ntom, wettability ntawm electrode thiab electrolyte, thiab cais, thiab lwm yam, tag nrho cov cuam tshuam rau qhov kub thiab txias ntawm lithium-ion roj teeb. Tsis tas li ntawd, kev cuam tshuam ntawm cov khoom siv thiab cov txheej txheem tsis raug ntawm qhov kev ua haujlwm kub ntawm lub roj teeb tsis tuaj yeem tsis quav ntsej.

Sau npe

Txhawm rau kom ntseeg tau tias qhov ntsuas kub tsis zoo ntawm cov roj teeb lithium-ion, cov ntsiab lus hauv qab no yuav tsum tau ua:

(1) Tsim ib zaj duab xis nyias thiab ntom ntom SEI;

(2) Xyuas kom meej tias Li + muaj qhov sib txawv loj hauv cov khoom siv;

(3) Cov electrolyte muaj siab ionic conductivity ntawm qhov kub thiab txias.

Tsis tas li ntawd, kev tshawb fawb tseem tuaj yeem nrhiav lwm txoj hauv kev los saib lwm hom lithium-ion roj teeb-tag nrho-lub xeev lithium-ion roj teeb. Piv nrog rau cov roj teeb lithium-ion cov khoom siv, cov roj teeb uas muaj zog tag nrho ntawm lub xeev lithium-ion, tshwj xeeb tshaj yog tag nrho cov khoom-state nyias-film lithium-ion roj teeb, xav kom daws tau tag nrho cov teeb meem ntawm lub peev xwm lwj thiab lub voj voog kev nyab xeeb thaum siv roj teeb ntawm qhov kub thiab txias. c