Ib txoj kev tshiab rau kev ntsuam xyuas silicon anode degradation yog xav kom ua tiav cov roj teeb zoo dua

Cov kws tshawb fawb qhia tias ib txoj hauv kev tshiab rau kev tsim cov qauv thiab tshuaj evolution ntawm silicon, nrog rau cov txheej nyias nyias tswj cov roj teeb ruaj khov, tuaj yeem pab daws qhov teeb meem ntawm kev tiv thaiv kev siv silicon hauv cov roj teeb muaj peev xwm.

Lub hom phiaj ntawm kev tshawb fawb yog nyob rau hauv kev sib tshuam ntawm anode, tsis zoo electrode, thiab electrolyte, uas tso cai rau tsub kom txav ntawm lub anode thiab lwm electrode (cathode). Cov khoom electrolyte interphase (SEI) txheej feem ntau yog tsim los ntawm electrode nto ntawm cov khoom electrode thiab cov kua electrolyte, uas yog ib qho tseem ceeb heev rau cov tshuaj electrochemical hauv cov roj teeb thiab tswj kev ruaj ntseg ntawm cov roj teeb. Siv silicon ua anode tuaj yeem ua tiav cov roj teeb zoo dua.

Nyob rau hauv 10 xyoo dhau los, silicon tau nyiam ntau cov xim raws li qhov muaj peev xwm tsis zoo electrode rau cov roj teeb rov qab. Xib fwb Zhang Sulin ntawm Engineering Science thiab Mechanics thiab Biotechnology tau hais tias tam sim no cov roj teeb lag luam siv graphite ua cov khoom siv hluav taws xob tsis zoo, tab sis silicon lub peev xwm yog li 10 npaug ntawm graphite. Yog li ntawd, muaj kaum tawm lab, pua pua lab, lossis txawm ntau pua lab nyiaj tau mob siab rau kev tshawb fawb silicon roj teeb.

Rau ib lub zej zog uas cia siab tias yuav siv hluav taws xob rau nws cov vaj tse los ntawm cov tsheb hluav taws xob thiab cov khoom siv hluav taws xob uas muaj zog, qhov no yog xov xwm zoo, tab sis kuj tseem muaj cov teeb meem. Thaum lub sij hawm them nyiaj thiab tso tawm cov txheej txheem ntawm cov roj teeb, lub ntim ntawm silicon yuav nthuav dav thiab cog lus, ua rau tawg ntawm cov khoom siv silicon, thiab SEI yuav tawg thiab rov tsim dua ib zaug. Qhov no yuav ua rau poob ntawm kev sib cuag hluav taws xob thiab txo lub peev xwm, uas yog tus nqi khaws cia hauv lub roj teeb.

Kev nkag siab meej txog yuav ua li cas cov txheej txheem no nthuav tawm cov txheej txheem thiab tshuaj lom neeg yog qhov tseem ceeb rau kev daws teeb meem.

Vim tias qhov ruaj khov ntawm cov txheej txheem no tswj kev ruaj ntseg ntawm lub roj teeb, koj tsis xav kom nws loj hlob uncontrollably vim tias cov txheej txheem no yuav haus cov khoom siv electrolyte thiab cov lithium active. Zhang tau hais tias qhov no yuav ua rau cov electrolyte qhuav thiab cov khoom siv tau ploj mus, yog li muaj kev cuam tshuam tsis zoo rau lub roj teeb ua haujlwm.

Ib qho kev sib tw loj uas Zhang thiab nws pab neeg tau nthuav tawm hauv phau ntawv journal Nature Nanotechnology yog lub peev xwm los saib xyuas, ua tus yam ntxwv, thiab nkag siab txog cov txheej txheem no.

Lub SEI txheej yog qhov tseem ceeb rau cov roj teeb, Zhang hais tias, tab sis nws yog nyias thiab tsis tuaj yeem pom nyob rau hauv ib qho khoom siv kho qhov muag, thiab nws hloov zuj zus mus thaum lub roj teeb caij tsheb kauj vab. Nws tuaj yeem raug pom los ntawm kev xa hluav taws xob microscopy ntawm nanoscale heev, cov ntaub ntawv nyias heev. Tab sis rau SEI, txheej no yog mos heev thiab yooj yim puas los ntawm electron kab teeb, raws li koj yuav tsum xa ib tug loj npaum li cas ntawm electrons kom tau txais high-resolution dluab ntawm cov khoom muaj pes tsawg leeg.

Txhawm rau kov yeej qhov teeb meem no, cov kws tshawb fawb tau siv qhov ntsuas kub qis ntawm kev xa hluav taws xob hluav taws xob microscopy (cryo STEM). Lawv khaws cov khoom siv hluav taws xob uas tsis muaj qhov kub thiab txias thaum lub sij hawm npaj thiab siv qhov ntsuas kub ntawm STEM microscopy imaging kom txo cov kab hluav taws xob puas tsuaj rau cov qauv. Tsis tas li ntawd, lawv tau koom ua ke rhiab ntsiab tomography rau 3D imaging thiab advanced algorithms tsom rau kev ntes dluab ntawm qis electron koob. Cov thev naus laus zis no ua tiav 3D pom ntawm SEI silicon kev sib cuam tshuam, ntes tom qab lub roj teeb sib txawv.

Lub uniqueness ntawm peb txoj kev yog nyob rau hauv qis-kub STEM imaging thiab ntau lub cev txheej txheem qauv. Zhang tau hais tias peb tuaj yeem pom qhov kev hloov pauv ntawm silicon thiab SEI tom qab lub roj teeb caij tsheb kauj vab; Lub caij no, peb tuaj yeem siv cov kev sim ua piv txwv los rov txheeb xyuas tag nrho cov txheej txheem microstructure evolution thaum lub voj voog. Nov yog qhov tshiab ntawm txoj kev tshawb no.

Kev ua haujlwm ntawm pab pawg no tau ua rau tib neeg kom nkag siab zoo txog cov txheej txheem uas ua rau muaj kev loj hlob thiab tsis ruaj khov ntawm SEI txheej hauv silicon anodes.

Yog li ntawd, nrog rau kev nkag siab txog txoj kev loj hlob ntawm SEI txheej, qhov no yuav ua rau peb muaj ntau yam kev nkag siab txog yuav ua li cas txhim kho kev ua tau zoo ntawm silicon anodes lossis roj teeb tsim, Zhang hais. Tom qab ntawd peb tuaj yeem tsim cov silicon anodes uas muaj zog dua rau tiam tom ntej ntawm lithium roj teeb.

Nws piav qhia tias tiam tom ntej ntawm lithium roj teeb yuav coj ntau yam txiaj ntsig rau kev lag luam thiab cov neeg siv khoom zoo tib yam.

Silicon muaj ntau heev, thiab yog tias peb tuaj yeem siv silicon ua anode nrog lub neej voj voog ntev, peb yuav ua kom muaj peev xwm ntawm cov roj teeb rov qab, Zhang tau hais. Ntxiv mus, vim muaj cov khoom siv silicon ntau, qhov no yuav txo tus nqi ntawm cov roj teeb.

Nrog rau kev nkag siab tseem ceeb ntawm cov evolution ntawm SEI txheej thaum lub sij hawm them thiab tso tawm ntawm silicon tsis zoo electrode roj teeb, Zhang tau hais tias cov kauj ruam tom ntej no yuav yog siv cov kev paub no los pab tsim cov roj teeb silicon tsis zoo electrode uas yuav tsis poob peev xwm vim kev caij tsheb kauj vab.

"Nrog kev nkag siab txog cov txheej txheem muaj peev xwm, cov kauj ruam tom ntej yog los tsim qee qhov kev xav txog kev tshawb fawb," Zhang hais. Tom qab ntawd, peb yuav sim qhov kev xav no siv lub silicon anode kom peb tuaj yeem txo cov kev tsis zoo cuam tshuam nrog kev hloov pauv ntawm silicon ntim. Los ntawm kev tswj cov yam tsis muaj kev tswj xyuas tam sim no, peb tuaj yeem tsim silicon electrodes nrog kev ua haujlwm zoo dua.

Cov kws tshawb fawb los ntawm Pennsylvania State University, nrog rau Zhang, koom nrog txoj kev tshawb no, suav nrog engineering science thiab mechanics kawm tiav cov tub ntxhais kawm Tianwu Chen thiab Dingchuan Xue. Lwm cov kws tshawb fawb suav nrog Yang He, Xu Yaobin, Wang Chongmin, Jia Haiping, Ran Yi, Miao Song, Li Xiaolin, thiab Zhang Jiguang los ntawm Pacific Northwest National Laboratory; Los ntawm ThermoFisher Scientific, LinJiang, ArdaGenc, ​​CedricBouchet Marquis, Lee Pullan, thiab TedTessner; Los Alamos National Laboratory, JinkyoungYoo. Ministry of Energy thiab National Science Foundation tau txhawb nqa qhov kev tshawb fawb no.