Roj teeb Graphene: A Myth Lossis Npuas?

Cov nqi sib tw ntsib lithium-ion roj teeb

Ob xyoo dhau los txij li thaum tau los tsim cov roj ntsha lithium-ion, peb lub ntiaj teb thiab lub neej tau coj lub ntiaj teb hloov pauv. Lub zog tshwj xeeb ntawm lub zog thiab lub zog ua haujlwm siab yuav tsum ua ntawm cov cuab yeej siv hluav taws xob khaws cia xws li cov khoom siv hluav taws xob thiab cov hluav taws xob tsheb tau ua rau cov roj teeb uas muaj tam sim no ntawm cov roj teeb hluav taws xob" tawg" ;. Kev hloov kho ntawm cov roj teeb thev naus laus zis tau poob qis dua qhov kev txhim kho ntawm cov khoom siv hluav taws xob thiab tau dhau los ua qhov kev txwv ntawm cov neeg siv kev paub. Qhov loj tshaj plaw.

Cov roj ntsha lithium-ion niaj hnub ua raws li kev hloov ntawm cov roj ntsha lithium uas nquag ua haujlwm nruab nrab ntawm cov ntaub ntawv zoo thiab tsis zoo kom ua tiav ntawm kev hloov pauv ntawm cov khoom siv hluav taws xob thiab lub zog hluav taws xob. Txawm li cas los xij, nws yog qhov tseeb ntawm cov tshuab electrochemical ntawm kev nkag thiab rho tawm uas ua rau lub peev xwm thiab lub zog ntawm cov roj ntsha lithium-ion uas tsis muaj peev xwm ua kom tau raws li qhov xav tau ntawm daim ntawv thov teeb meem. Hais txog cov ntaub ntawv tsis zoo electrode, cov khoom siv tsis zoo electrode ntawm kev lag luam roj teeb lithium-ion sawv cev los ntawm graphite siv lithium ions rau kev deintercalate ntawm graphite txheej ua haujlwm. Txawm li cas los xij, cov chaw ntawm lithium nyob rau hauv graphite thiab interlayer spacing ntawm graphite nws tus kheej yog qhov tsawg heev, uas yuam lithium-ion roj teeb kom ntsib cov teeb meem ntawm qhov tsis muaj peev xwm thiab lub zog qis.

Graphene roj teeb: muab tawm

Nyob rau lub sijhawm thaum tib neeg poob ntawm qhov kev poob, qhov tshiab ntawm lub hnub qub carbon cov khoom siv-graphene tau tawm! Graphene tuaj yeem raug suav tias yog ib txheej-graphite, uas muaj cov chaw lithium sib txuas ntxiv, thiab muaj cov tshuab hluav taws xob muaj hluav taws xob ntau dhau thiab muaj cov nplaim loj. Nyob rau hauv txoj kev no, tuaj yeem graphene hloov graphite kom tawg qhov kev hloov hauv lub zog txuag hluav taws xob? Nrog lub peev xwm loj, lub zog siv hluav taws xob, thiab them ceev ceev, tsis txhob' t no" Peach Blossom Springs" uas tib neeg tau caum ncaj qha mus ua kev muaj tiag? ! Ntau cov xov xwm kuj tau pib tshaj tawm txog qhov zoo ntawm graphene roj teeb thiab ua hype. Rau ib lub sijhawm, graphene roj teeb ntsig txog lub tswv yim cov ntsiab lus tau dhau los ua neeg nyiam. Txhua txoj kev lag luam roj teeb zoo li tau raug ntaus. Txhua tus tau saib tom ntej rau graphene roj teeb. Cov tuaj txog ntawm lub sijhawm.

Txawm li cas los xij, qhov no puas yog? Cov ntsiab lus hauv qab no tsuas yog los ntawm kev tshawb pom los ntawm kev tshawb pom kom pom daim ntaub thaiv ntawm lub roj teeb tsis sib xws rau txhua tus (Ceeb toom: roj teeb Graphene tseem tsis tau muaj lub tswv yim meej, raws li lub luag haujlwm ntawm graphene tuaj yeem raug faib ua graphene ua tus coj ntxiv thiab graphite Muaj ob hom ene uas yog cov khoom siv tsis zoo electrode. Tsab xov xwm no tham txog graphene ua qhov tsis zoo electrode ntawm lub roj teeb).

keeb kwm

Hauv xyoo 2014, Ntawv Tshaj Tawm Kev Tshaj Tawm tau tshaj tawm ua haujlwm rau txhua qhov-graphene lithium roj teeb. Hauv txhua lub roj teeb-graphene no, qhov hluav taws xob zoo yog qhov muaj cov khoom siv tiv thaiv zoo rau hauv av, thiab cov hluav taws xob tsis zoo yog txo cov graphene oxide. Lub roj teeb tag nrho siv cov tshuaj tiv thaiv sab saum toj ntawm qhov zoo thiab tsis zoo electrodes, yog li nws muaj peev xwm ua tiav super-siab tus nqi them thiab tawm. Lub zog ceev tau muab xam raws li cov hluav taws xob zuag qhia tag nrho tuaj yeem ncav cuag 2150W / kg.

Los ntawm lub zog ntom ntom pom ntawm lub zog, lub roj teeb tau muaj tseeb, tab sis thaum peb saib lub zog ceev dua, peb tuaj yeem pom tias lub zog ntom ntom tau xam raws qhov loj ntawm ob lub electrodes tsuas yog 130Wh / kg, uas tsuas yog tau kom ncav cuag cov roj teeb lithium-ion uas twb muaj lawm raws li lub tshuab huab hwm coj (lub zog hluav taws xob ntawm cov roj teeb ntawm BYD nrov tam sim no yog 140Wh / kg;" Tau ua nyob rau hauv Suav Teb 2025" hais meej meej tias tib lub zog ntawm tsheb -cov roj teeb fais fab loj yuav tsum ncav cuag 300Wh / kg los ntawm 2020). Yog tias nws tau muab tso ua ke rau hauv kev siv roj teeb, nws lub zog loj txaus yuav txo qis los ntawm lwm tsib mus rau caum feem pua. Ntxiv mus, cov ntaub ntawv zoo thiab tsis zoo ntawm cov khoom siv roj teeb ntawm cov roj teeb no tsis muaj cov roj ntsha lithium, yog li lub tshuab hluav taws xob ua ntej cov roj hluav taws xob hauv lub roj ib nrab yuav tsum tau nqa tawm ua ntej txuam nrog lub roj teeb puv. Saib nws txoj hauv kev no, roj teeb graphene tuaj yeem yog thawj qhov tsim kho hauv kev muaj peev xwm ntau, tab sis lawv lub zog ceev tseem nyob deb ntawm cov neeg' s kev cia siab.

Yog li hauv kev tshawb xav, muaj peev xwm siv graphene ua cov khoom siv tsis zoo electrode rau roj teeb zoo li graphite? Puas yog qhov tshuab ntawm cov roj ntsha lithium zoo ib yam li graphite? Dab tsi yog nws qhov theoretical lithium cia muaj peev xwm? Ntau tus kws tshawb fawb ntseeg tias vim hais tias graphene muaj ob sab uas tuaj yeem adsorb lithium atoms, nws tuaj yeem tsim ua ob theem lithium ntawm Li2C6 thiab muaj qhov tshwj xeeb ob npaug ntawm 744 mAh / g. Muaj ntau txoj kev tshawb fawb txog cov teeb meem no. Qee cov kws tshawb nrhiav tau siv DFT cov kev suav kom pom tias lithium atoms tsis tuaj yeem ncaj qha rau ntawm cov nplaim graphene. Lawv tsuas yog tuaj yeem muab nruab nrab ntawm txheej txheej graphene lossis mus rau hauv nruab nrab ntawm graphene thiab substrate los ntawm cov npoo los yog kev txiav txim siab tsis zoo. Yog li qhov xwm txheej no, puas yog deintercalation lossis adsorption, thiab muaj pes tsawg tus Li atoms tuaj yeem khaws cia?

Coob

Teb rau cov teeb meem no, Associate Professor Ji Kemeng ntawm Tianjin University tau tshaj tawm nws txoj kev tshawb fawb txog cov lithium intercalation mechanism ntawm ob-txheej graphene nyob rau hauv Kev Sib Txuas Lus hauv Xyoo 2019. Lawv tau siv lub siab kub hloov mus rau tshuaj vapor deposition txoj kev los npaj ob txheej txheej graphene cov khoom siv nrog lub siab tshwj xeeb saum npoo. Cov khoom siv no tsis tas yuav txuas rau qhov tsis yooj yim thiab muaj qee qhov tsis xws luag, yog li tus cawv ntawm lub zog thiab cov tsis xws luag ntawm adsorption lossis deintercalation ntawm lithium ions tuaj yeem tshem tawm, uas tau txais txiaj ntsig zoo rau kev kawm txog cov mechanism ntawm deintercalation ntawm lithium hauv graphene nws tus kheej. Cov kev ntsuas hluav taws xob tsis tu ncua tam sim no thiab cov hluav taws xob voltammetry nkhaus qhia tau tias ob chav txheej graphene muaj tib lub tshuab electrochemical oxidation-txo cov tshuaj tiv thaiv zoo li cov pa hluav taws xob, thiab cov lithium ions yog deintercalated ntawm ob daim ntawv graphene. Graphene txheej spacing yog qhov chaw tsuas yog rau kev cia lithium, thiab lub tswv yim ntawm kev nqus thiab khaws cov lithium yog kev tiv thaiv tus kheej! Kuj tseem muaj qhov tshwm sim zoo tshaj plaws. Lub peev xwm ntau tshaj plaws ntawm ob-txheej graphene tsuas yog 180 mAh / g hauv qhov ntsuas kub ntau ntawm 0.2-50 A / g. Cov cim ntu tom ntej qhia tau hais tias lub thaj ua rau thaj chaw ntawm lithium cia theem yog LiC12 thiab LiC6 ntawm qhov tsis-graphite electrode tsis yog lub npe hu ua dual lithium cia Li2C6 theem.

Cov kev tshawb nrhiav pom no qhia tau tias Daumas-Hérold' s sau qauv zoo dua rau kev piav qhia txog lithium cia tus cwj pwm ntawm graphite electrodes dua li Rüdorff' s qauv, thiab tau xaus rau ib nrab sib cav txog ntawm lithium cia mechanism ntawm graphite. Nyob rau tib lub sijhawm, theoretical lithium cia muaj peev xwm ntawm graphene thaum kawg tau lees tias, thiab qhov theoretical muaj peev xwm ntawm 180mAh / g yog qhov ua tsis tau zoo rau lub electrochemical lithium cia muaj peev xwm ntawm graphite anode. Lub graphene roj teeb npuas tsoo nws tus kheej!

Kev ntseeg siab

Yog li, qhov twg muaj peev xwm ntawm graphene qhia nyob rau hauv ntau cov ntaub ntawv tuaj? Peb paub tias cov khoom siv graphene uas tib neeg feem ntau ua rau tsis zoo dua tshiab graphene zoo li cov saum toj no. Ntau qhov graphenes peb tuaj yeem tau txais kev nplua nuj nyob hauv qhov tsis xws luag (suav nrog ob leeg lub cev tsis zoo ntawm cov khoom siv carbon thiab cov tsis xws luag los ntawm qhov tshwj xeeb qhia heteroatom chaw), thiab cov nplaim yog ntau yam ntawm cov pawg ua haujlwm (xws li carboxyl, hydroxyl, Cov pab pawg no tau yooj yim rau kev sib txuas nrog tshuaj sib tov nrog lithium, xws li epoxy pab pawg). Lub superposition ntawm cov yam thiab qhov loj loj tshwj xeeb thaj tsam thaj av ntawm graphene nws tus kheej yuav ua rau ntau cov lithium tsis koom nrog cov tshuaj tiv thaiv electrochemical nyob rau hauv daim ntawv deintercalation, tab sis los pab txhawb rau pseudocapacitance hauv daim ntawv ntawm adsorption. Cov teebmeem pseudocapacitance no ua rau nws pom tias lub peev xwm graphene muaj peev xwm ntau thiab cov tshuab hluav taws xob electrochemical yog qhov ceev, tab sis qhov no tau cuam tshuam me ntsis ntawm qhov nce ntawm lub zog ceev ntawm lub roj teeb tag nrho. Ntxiv mus, thaj chaw muaj tshuaj tiv thaiv ntau thiab cov ntsiab lus tiv thaiv tsis txaus siab tseem yuav ua rau cov roj ntsha tsis tshua muaj siab mus txuas ntxiv, uas ua rau txo qhov kev ua tau zoo ntawm coulombic efficiency, uas ua rau muaj kev phom sij rau lub peev xwm ruaj khov ntawm lub roj teeb puv.

lawm yav tom ntej

Tom qab kev txheeb xyuas saum toj no, graphene ua qhov tsis zoo electrode rau cov roj teeb tsis muaj kev cia siab yog tias nws xav nkag mus rau ntau txhiab tsev neeg. Txawm li cas los xij, qhov no tsis txhais tau hais tias graphene tsis muaj nuj nqis nyob rau hauv kev lag luam ntawm lub zog cia. Ntxiv nrog rau kev ua lithium cia, graphene nws tus kheej kuj muaj ultra-siab hluav taws xob kev ua haujlwm thiab zoo heev thermal conductivity. Ob yam ua rau hluav taws xob thiab cua sov ua lub luag haujlwm tseem ceeb hauv cov roj teeb tiag. Tshwj xeeb yog thaum tshav kub kub, roj teeb kev nyab xeeb teeb meem los ntawm thermal khiav tawm haujlwm tuaj yeem txawm tias veto ntau cov khoom siv hluav taws xob nrog kev ua tau zoo electrochemical. Yog tias qhov zoo ntawm ob qho hluav taws xob thiab thermal conductivity siv rau lub roj teeb," graphene roj teeb" kuj tuaj yeem ci.

Tau kawg, raws li hom khoom siv tej yam yees siv, graphene tsis paub tias nws yuav coj qhov kev hloov pauv tshiab rau lub roj teeb nyob rau lwm txoj kev? Cia li zoo li cov ntaub ntawv tshaj tawm tsis ntev los no los ntawm cov chaw tsis paub, Mercedes-Benz tab tom txhim kho graphene-based organic roj teeb. Cov tshuab tshwj xeeb tseem tsis tau qhia tawm. Xijpeem, nws yuav yog tsawg kawg 10 xyoo tom qab. Txawm hais tias nws yog qhov hloov dua tshiab lossis npuas tshiab, peb yuav tos thiab pom!

Hauv ntej, thaj teb ntawm lub zog cia, uas yog lub hom phiaj ntawm kev siv tau tiag tiag, tsis yog" kev sib tw hnub qub" ;. Raws qhov tseeb tau graphene electrode tsis zoo yuav tsum muaj cov xwm txheej hnyav heev (zoo meej graphene). Hauv qhov kev ua khoom tiag tiag, nws yog qhov tsim nyog los them tus nqi siab, uas yog qhov tsis sib xws nrog lub tswv yim qub ntawm nce lub zog ceev thiab txo tus nqi tsim khoom. Dab tsi' s ntxiv, theoretical feasibility thaum kawg ua pov thawj tias tsis tuaj yeem tsim nyog. Lwm zaus yuav muaj xov xwm hype txog" roj teeb graphene", koj yuav tsum ua kom koj lub qhov muag qhib kom pom meej meej