Cov kws tshawb fawb tau tshawb pom qhov ua rau muaj kev tawg tsis tu ncua hauv cov roj teeb lithium-ion!

Nrog rau kev txhim kho sai ntawm cov khoom siv hluav taws xob thiab lub tsheb hluav taws xob, tib neeg tsis yog tsuas yog nrhiav kev muaj peev xwm loj dua thiab kev them nqi sai dua thiab tso tawm ceev ntawm lithium roj teeb, tab sis tseem txhawj xeeb ntxiv txog yuav ua li cas kom muaj kev nyab xeeb ntawm lithium roj teeb siv. Vim muaj qee qhov xwm txheej xws li cov roj teeb lithium tawg, ib tus neeg lub paj hlwb tsis muaj zog. Qhov yuav tsum tau ua ua ntej los daws cov teeb meem kev nyab xeeb ntawm cov roj teeb lithium yog rau cov kws tshawb fawb kom muaj kev nkag siab zoo thiab kev nkag siab zoo ntawm cov laj thawj ntawm lithium roj teeb tawg.

Cov lus piav qhia txog kev tshawb fawb tam sim no yog tias lithium deposition ntawm lub electrode nto yuav tsim dendrites, uas yuav loj hlob mus ntxiv, ua rau cov luv luv Circuit Court nyob rau hauv lub roj teeb, ua rau lub roj teeb tsis ua hauj lwm los yog tej zaum yuav hluav taws kub. Tab sis yav dhau los, muaj qhov tsis muaj peev xwm ua tau zoo kom nkag siab thiab kawm los ntawm kev xav ntawm cov qauv atomic, thiab tom qab ntawd nrhiav kev daws teeb meem.
Lub tshuab cryo EM, uas yeej 2017 Nobel nqi zog hauv Chemistry lub hlis no, muab kev txhawb zog rau qhov no. Pab pawg tshawb fawb coj los ntawm xibfwb Cui Yi los ntawm Stanford University thiab SLAC National Accelerator Laboratory ncaj qha nyob rau hauv US Department of Energy, nrog rau Nobel laureate Steven Chu hauv 1997, tau ntes thawj daim duab ntawm qib atomic lithium hlau dendrites siv cryo electron microscopy ( cryo EM). Cov kev tshawb fawb tshawb fawb tau luam tawm nyob rau hauv thoob ntiaj teb kev kawm ntawv journal Science nyob rau lub kaum hli ntuj 27th lub sij hawm hauv zos.
Txhua lithium hlau dendrite yog ntev, zoo kawg nkaus tsim hexagonal siv lead ua. Yav dhau los, tsuas yog irregularly zoo li crystals tau pom los ntawm electron microscopy. Cui Yi tau hais tias, "Cov txiaj ntsig kev tshawb fawb tau zoo siab heev thiab tau qhib lub sijhawm tshiab rau kev tshawb fawb ntsig txog!"

Cryoelectron microscope, raws li lub npe qhia, yog cov txheej txheem microscopic uas siv cryofixation los soj ntsuam cov qauv ntawm qhov kub thiab txias siv Transmission Electron Microscope (TEM). Cryoelectron microscopy yog ib qho tseem ceeb ntawm cov qauv kev tshawb fawb txog biology thiab ib qho tseem ceeb ntawm kev tau txais cov qauv ntawm biomolecules.

Vim hais tias cov duab yog tus yuam sij rau kev nkag siab txog cov txheej txheem, kev tshawb fawb feem ntau tso siab rau kev siv lub qhov muag liab qab kom tau txais cov duab pom ntawm lub hom phiaj. Tau ntev, nws tau ntseeg tias TEM tsis haum rau kev soj ntsuam biomolecules vim cov kab hluav taws xob muaj zog tuaj yeem ua rau cov khoom siv lom neeg puas tsuaj. Txawm li cas los xij, qhov tshwm sim ntawm cryo electron microscopy tau ua rau cov kws tshawb fawb "kho" biomolecules thiab saib thiab txheeb xyuas lawv cov txheej txheem kev txav tsis tau muaj dua. Cov cwj pwm no muaj kev txiav txim siab rau kev nkag siab ntawm biochemistry thiab kev loj hlob ntawm pharmacology. Yog li ntawd, cryo electron microscopy tseem yuav suav nrog xyoo no Nobel nqi zog hauv Chemistry.
Rau cov ntaub ntawv xws li lithium, nws tseem tsis tuaj yeem siv lub tshuab ntsuas hluav taws xob los saib cov txiaj ntsig ntawm qib atomic ntawm dendrites. Zoo ib yam li biomaterials, thaum siv TEM nyob rau hauv chav tsev kub, cov npoo ntawm dendrites yuav curl los yog txawm yaj vim yog electron beam cuam tshuam. Yanbin Li, tus kws kho mob ntawm Stanford University uas tau koom nrog hauv txoj haujlwm no, tau hais tias, "Kev npaj cov qauv xa hluav taws xob hauv tshuab hluav taws xob tau ua tiav hauv huab cua, tab sis lithium hlau yuav sai sai hauv huab cua." "Thaum twg peb sim soj ntsuam lithium hlau nyob rau hauv lub tshuab hluav taws xob hluav taws xob siab, cov hluav taws xob yuav 'xov qhov' hauv cov dendrites thiab txawm tias nws yaj tag."
Yanbin Li, tus tub ntxhais kawm PhD los ntawm Stanford University uas koom nrog txoj kev tshawb no, hais tias, "Nws zoo li ci ntsa iab iav rau ntawm nplooj nyob rau hauv tshav ntuj. Txawm li cas los xij, yog tias koj tuaj yeem txias nplooj, qhov teeb meem no yuav daws tau yooj yim: yog tias koj tsom teeb. ntawm nplooj ntawv, cov cua sov kuj tseem yuav ploj mus, thiab cov nplooj yuav tsis raug puas ntsoog qhov no yog qhov peb tuaj yeem ua tiav nrog lub tshuab hluav taws xob cryoelectron, thiab qhov sib txawv ntawm cov duab thaum siv cov khoom siv roj teeb yog qhov pom tseeb heev.

Yog li, cryo electron microscopy tsis tau tsuas yog ushered nyob rau hauv ib tug tshiab era nyob rau hauv biochemistry, tab sis kuj tso cai rau cov kws tshawb fawb pom tag nrho cov qauv ntawm lithium dendrites ntawm qib atomic thawj zaug. Cov kws tshawb fawb kuj pom tias dendrites hauv carbonate raws li electrolytes loj hlob nyob rau hauv ib qho kev taw qhia rau ib leeg siv lead ua nanowires. Qee tus ntawm lawv tej zaum yuav muaj knotting thaum lub sij hawm txoj kev loj hlob, tab sis lawv cov qauv siv lead ua tseem tsis zoo.

Yuzhangli, lwm tus kws kho mob hauv University of Stanford uas tau koom nrog hauv kev tshawb fawb no, tau hais tias cov khoom siv hluav taws xob cuam tshuam lub ntsej muag lub ntsej muag (SEI) kuj tuaj yeem pom, thiab kuj tau nthuav tawm SEI nanostructures sib txawv hauv cov electrolytes sib txawv. Vim tias tib txheej txheej kuj tseem ua rau ntawm cov hlau electrode thaum lub roj teeb raug them thiab tawm, tswj nws cov cim thiab kev ruaj ntseg yog qhov tseem ceeb rau kev siv lub roj teeb kom zoo.
Los ntawm kev siv cryo EM, cov kws tshawb fawb tuaj yeem soj ntsuam seb cov electrons eject tawm ntawm atoms hauv dendrites, yog li nthuav tawm txoj hauj lwm ntawm ib tus neeg atoms. Cov kws tshawb fawb tseem tuaj yeem ntsuas qhov kev ncua deb ntawm atoms, thiab qhov sib nrug ntawm atomic precisely qhia tias lawv yog lithium atoms.
Cov ntawv xov xwm tso tawm los ntawm SLAC qhia tau hais tias nyob rau hauv lub tshuab tsom iav, cov kws tshawb fawb siv cov tswv yim sib txawv los soj ntsuam txoj kev electrons raug tshem tawm ntawm cov atoms ntawm lub dendrite, nthuav tawm txoj hauj lwm ntawm ib qho atom hauv lub ntsej muag daim npog ntsej muag ntawm cov siv lead ua thiab nws cov khoom electrolyte interface. . Thaum lawv ntxiv cov tshuaj uas nquag siv los txhim kho cov roj teeb ua haujlwm, cov qauv atomic ntawm cov khoom electrolyte interface lub ntsej muag daim npog ntsej muag yuav ua kom zoo dua qub, uas yuav pab piav qhia vim li cas cov khoom siv ntxiv ua lub luag haujlwm.
"Peb zoo siab heev. Nov yog thawj zaug uas peb tuaj yeem tau txais cov duab ntxaws ntxaws ntawm dendrites, thiab nws tseem yog thawj zaug uas peb tuaj yeem pom cov nanostructure ntawm cov khoom siv electrolyte interface lub ntsej muag npog txheej." YanbinLi tau hais tias, "Qhov cuab yeej no tuaj yeem pab peb nkag siab lub luag haujlwm ntawm cov electrolytes sib txawv, thiab vim li cas qee cov electrolytes muaj txiaj ntsig zoo dua li lwm tus."
Cov ntaub ntawv cuam tshuam tau pom los ntawm cov kev sim no tuaj yeem muab kev nkag siab ntxiv ntawm cov roj teeb tsis ua haujlwm. Txawm hais tias txoj haujlwm no yog siv lithium hlau ua piv txwv los ua kom pom qhov ua tau zoo ntawm cryo EM, txoj kev no kuj tseem tuaj yeem txuas ntxiv mus rau lwm cov kev tshawb fawb txog cov khoom siv hluav taws xob xws li lithium silicon lossis sulfur. Pab pawg tshawb fawb kuj tau hais tias lawv tau npaj los tsom mus rau kev nkag siab ntau ntxiv ntawm cov khoom siv tshuaj lom neeg thiab cov qauv ntawm cov khoom siv electrolyte lub ntsej muag daim npog ntsej muag.