Dab tsi Yog Cov Ntsiav Tshuaj Lithium-sulfur?

Lithium-ion roj teeb (LiCo02) yog cov roj teeb hluav taws xob ib leeg, thaum lithium-sulfur roj teeb yog 8-electron redox, yog li lithium-sulfur roj teeb muaj qhov kev xav tias lawv yog 7-8 zaug ntawm lub peev xwm ntawm lithium-ion roj teeb. Txawm hais tias polymer lithium roj teeb tau siv dav hauv 3C cov khoom, vim tias lub zog siv tsawg, uas yog, lub sijhawm siv roj teeb tsawg, lawv yuav tsum tau them ntau zaus, uas yog ib qho teeb meem. Qhov kev xav paub ntau tshaj plaws yog tias tom qab hloov lub xov tooj ntse, txhua tus tau them nyiaj txhua txhua hnub, thiab txawm tias lub xov tooj tau them yuav tsis tawm hauv lub xeev. Niaj hnub no lub neej xav tau ib hom tshiab ntawm cov roj teeb lithium-ion uas tsis tshua muaj nqi, tsis muaj kuab paug, ua haujlwm ruaj khov, muaj peev xwm loj, thiab lub zog siv hluav taws xob kom tau raws li cov kev xav tau ntev roj teeb thiab lub zog them ceev.

Keeb kwm kev loj hlob lithium-sulfur roj teeb: Lithium-ion roj teeb muaj keeb kwm ntau dua 30 xyoo, thiab cov roj teeb lithium-sulfur muaj hnub nyoog yau dua. Xyoo 1962, Herbet thiab Ulam thawj zaug tau thov siv cov leej faj li cov khoom siv cathode thiab alkaline perchlorate raws li cov tshuaj electrolyte.

Lub sijhawm lithium-sulfur system tau kawm ua thawj lub roj teeb thiab txawm tias tau ua lag luam rau ib lub sijhawm, tab sis nws tom qab tau hloov los ntawm roj teeb rov qab thiab muab tso rau tuav. Nyob rau xyoo 2009, Linda F. Nazar tau thov roj teeb lithium-sulfur roj teeb rov qab cov roj ntawm Cov Khoom Siv Xwm, thiab siv CMK-3 kom ua tiav lub siab muaj peev xwm ntawm 1320mAh / g. Txij thaum ntawd, lithium-sulfur roj teeb tau qhib lub tshooj ntawm kev tsim kho.

Lub hauv paus ntsiab lus ntawm lithium-sulfur roj teeb: qhov ua tau zoo ntawm cov roj teeb lithium-leej faj yog cov khoom sulfur lossis leej faj, thiab cov tsis zoo electrode yog lithium. Qhov nruab nrab voltage yog 2.1V. Hauv txoj kev xav, lithium-sulfur system (Li-S) muaj qhov tshwj xeeb muaj peev xwm ntawm 1672mAh / g thiab lub zog ceev ntawm 2600Wh / kg. Nws yog ib txwm muaj kev lag luam lithium ion roj teeb nrog LiCo02 raws li qhov zoo electrode (theoretical meej muaj peev xwm 273.8mAh / g, Lub zog ceev 360Wh / kg) txog 7 zaug. Piv nrog cov roj teeb lithium-ion zoo tib yam, qhov xwm ntawm qhov paug ntawm lithium-sulfur roj teeb tsis yooj yim lithium ion deintercalation, tab sis cov txheej txheem redox nrog cov ntau ntawm cov khoom theem nrab. Thaum lub sijhawm cov txheej txheem paug tawm ntawm lithium-sulfur paug roj teeb, cov ntsiab lus sulfur reacts nrog Li los ntawm lub nplhaib qhib ntawm cyclic S8, thiab kev hloov pauv los ntawm cov hlua ntev Li2S8 mus rau cov xov tooj luv luv Li2S yog nrog los ntawm ob qho kev ua kom pom kev tawm, lub siab muaj peev xwm tawm lub platform yog 2.45V—- 2.1V, cov txheej txheem tuaj yeem suav tias yog ntau ntawm S8 rau S42- hloov dua siab tshiab, thiab qhov poob qis qis qis yog 2.1V-1.7V, cov txheej txheem no yog qhov ntau ntawm S42- rau hauv S22- thiab S2 -. Ntawm qhov tod tes, sib txawv hloov pauv qib tseem sib xws rau cov khoom sib txawv.

Cov tshuaj tiv thaiv kev sib cais tawm yog li hauv qab no:

Cov electrode zoo: S8 {{1}} 16Li+e- → 8Li2S

Electrode tsis zoo: Li ++ Li++e-

Tag nrho cov tshuaj tiv thaiv: 2Li + nS → Li2Sn → Li2S

Cov roj teeb roj ntsha zoo tshaj yog cov roj teeb hluav taws xob ib leeg, thiab cov roj teeb lithium-sulfur yog 8-electron redox, yog li lawv muaj 7-8 npaug ntawm qhov theoretical muaj peev xwm thiab lub zog ceev. Zoo ib yam li cov roj ntsha lithium-ion, cov roj teeb lithium-sulfur muaj cov electrode zoo, qhov tsis zoo, cov hluav taws xob cais, cov roj ntsha thiab cov sib cais. Yog li, roj teeb lithium-leej faj yog suav tias yog qhov kev cog lus zoo tshaj plaws rau cov roj ntsha lithium-ion roj teeb thiab dhau los ua lub zog tshiab rau cov cim tshiab ntawm cov khoom siv hluav taws xob.

Sulphur cathode cov ntaub ntawv yog qhov tseem ceeb txwv rau kev tsim kho thiab siv cov roj teeb lithium-leej faj, yog li peb tsom mus rau leej faj cathodes. Nyob rau tam sim no, cov leej faj sulfur ntawm cov roj ntsha lithium-leej faj tseem muaj ntau yam teeb meem yuav tsum daws: cov nyhuv dhau mus, kev coj tsis zoo, thiab nthuav dav.

1. Polysulfides yaj thaum lub sij hawm tawm txheej txheem (Li2Sx, 3 ＜ x ＜ 8), ua rau muaj kev cuam tshuam tsis sib luag thiab" cov kev cuam tshuam shuttle", ua rau muaj kev tshem tawm ntawm tus kheej, txo qhov Coulomb efficiency thiab lub voj voog kev ua tau zoo, thiab ua rau lub peev xwm tsis muaj kev cuam tshuam;

2. Lub conductivity ntawm elemental sulfur thiab cov khoom tawm paug lithium sulfide tsawg, cov conductivity ntawm S (5 × 10-30S / cm, 25 ℃), kev coj ua ntawm Li2S / Li2S2 (~ 10-30S / cm), uas ua rau muaj txiaj ntsig kev siv cov leej faj tsuas yog Txog 50-70%.

3. Kev hloov pauv ntawm orthorhombic α-S (ρ1=2.03g / cm3) rau Li2S nrog cov qauv fluorite thim rov qab (ρ2=1.66g / cm3) muaj qhov loj ntim nthuav, rhuav tshem cov qauv hluav taws xob, thiab cuam tshuam rau lub voj voog kev ruaj khov.