◆Ingxubevange{0}}uhlobo lwemathiriyeli ye-anode
◆Uguqulo{0}}uhlobo lwemathiriyeli ye-anode
◆Izinto ze-lithium zesinyithi ze-anode
Kwinkqubo yokutshaja yeiibhetri ze-lithium{0}}, izinto ezingalunganga ze-electrode zidlala indima ebalulekileyo ekuthwaleni i-lithium ion kunye nee-electron, kwaye ziyimfuneko yokugcina amandla kunye nokukhululwa. Ngokwembono yeendleko, ezi mathiriyeli zithatha i-5% ukuya kwi-15% yexabiso lilonke lokwenziwa kwebhetri kwaye zithathwa njengenye yezinto eziyimfuneko ekrwada yemveliso yebhetri ye-lithium{3}}. Njengemathiriyeli ye-electrode eyakhayo, imathiriyeli ye-electrode engalunganga idlala indima ebaluleke kakhulu ekukhuthazeni ukuqhubela phambili kwe-lithium{5}}iteknoloji yebhetri ye-ion. Kwiminyaka yakutshanje, ngokunyuka kwemfuno yokuphucula ukusebenza kwebhetri{7}}ngokukodwa, ukufuna uxinano lwamandla aphezulu, ukuxinana kwamandla, kunye nozinzo lomjikelo olungcono kunye nokhuseleko{8}}abaphandi banike ingqwalaselo enkulu kwizinto ezimbi ze-electrode, enye yezinto eziphambili ze-lithium{9}}
iibhetri. Isixhobo esifanelekileyo se-electrode kufuneka sibe nezi mpawu zilandelayo:
(1) Ikhaphukhaphu, ehlala iLi kangangoko kunokwenzeka ukuze kunyuswe umthamo othile.
(2) I-redox ephantsi ye-redox yokufakwa kwe-lithium ion kunye ne-extraction reactions, enceda ukufezekisa i-voltage ephezulu yokuphuma kwebhetri.
(3) Ukuqhuba kakuhle kwe-elektroniki kunye ne-ionic.
(4) I-insoluble kwi-solvents ye-electrolyte kwaye ayiphenduli ngeetyuwa ze-lithium. 5
(6) Ubuncwane obungabizi kakhulu, buyintabalala, kwaye bunobuhlobo nemekobume.
Izixhobo ze-anode zinokwahlulwa zibe ziindidi ezimbini ezingundoqo ngokusekelwe kwimichiza yazo: iimathiriyeli ezisekelwe kwikhabhoni {{0}esekwe kunye{1}}ne{2}}engasekelwanga kwi-carbon{2}. Iimathiriyeli zeCarbon-zinokwahlulwa ngakumbi kwimathiriyeli yekhabhoni yegraphic kunye nemathiriyeli ye-amorphous carbon. Izinto ezingeyiyo{{6}ikhabhoni{7}}ezisekelwe ziquka isilicon{8}esekwe, i-titanium{9}esekwe, kunye nee-oxide zentsimbi ezahlukeneyo. Okwangoku, izixhobo ze-anode ezisetyenziswa ngokubanzi kwimarike ikakhulu zibandakanya iintlobo ezintathu: i-carbon{11}}izinto ezisekwe, i-lithium titanate (i-LiTisOi2), kunye nemathiriyeli ye-carbon composite ebandakanya i-silicon. Iimathiriyeli zeCarbon{14}zinokwahlulwa kwakhona zibe yigraphite (igraphite yendalo kunye neyendalo), ikhabhoni ethambileyo, kunye nekhabhoni eqinileyo. Phakathi kwezi ndidi, igraphite eyenziweyo ibambe esona sabelo sikhulu semarike.
Izixhobo ze-anode ezidibeneyo
izinto zekhabhoni
Kuphuhliso lweebhetri ze-lithium -i-ion, ukusungulwa kokusetyenziswa kwe-carbon{1}}izinto ezisekwe kwi-lithium yentsimbi njengoko i-anode iphawula impumelelo enkulu kobu buchwepheshe. Ukuza kuthi ga ngoku, alukho olunye uhlobo lwemathiriyeli ye-anode enokulingana neendleko -zokusebenza kunye nokusebenza; ngoko ke, kulindelekile ukuba ikharbhon{4}izinto ezisekiweyo ziyakuhlala zilolona khetho luphambili-kwizicelo ezinkulu zorhwebo kangangexesha elide. Ngokusekelwe kwiqondo le-graphitization, i-carbon{7}esekwe kwimathiriyeli esetyenziswa njenge-anode ingahlelwa ngokweendidi ezintathu: igraphite, i-soft carbon, kunye ne-hard carbon. -imathiriyeli yekhabhoni yegraphite zonke zibonisa utyekelo lokuguqukela kwigraphite ngexesha{10}}lokulungiswa kobushushu obuphezulu; nangona kunjalo, ezinye izinto zithandwa kakhulu kule nguqu kwaye zichazwa njengekhabhoni ethambileyo; ngelixa ezo zinzima ukugqiba inkqubo zibizwa ngokuba yikhabhoni enzima. Ngokuqhelekileyo, ikhabhoni ethambileyo inokufumaneka kwizinto eziluhlaza ezifana netela yamalahle okanye i-petroleum pitch; ngokuchaseneyo, i-carbon elukhuni ininzi idityaniswe kumacandelo afana ne-phenolic resin okanye i-sucrose. Okwangoku, esinye sezona zifundo zifundwe kakhulu kwikhabhoni ethambileyo yi-mesophase carbon microspheres. Zombini iimathiriyeli zegraphitic kunye nezingezizo{14}}graphitic carbon zineengenelo kunye nezingeloncedo zazo xa zisetyenziswa njenge electrode negative kwiibhetri ze-lithium{15}}. Ngokusekwe koku, abaphandi bahlala besebenzisa amacandelo ahlukeneyo{17}}ukuguqula nokuguqula umphezulu wezimathiriyeli zekhabhoni ukuze baphucule ukusebenza kwabo.
I-graphite, njengento eleleyo (Umfanekiso 5 -} 8), unesakhiwo sangaphakathi esiquka isakhelo esinehexagonal yee-athomu ezicwangciswe kwi-sp2 hybrid state, eyandisa kwimilinganiselo emibini. Ngaphakathi komaleko ngamnye, iiathom zekhabhoni zenza igridi eyomeleleyo enehexagonal enomgama we-carbon-carbon atom ye-0.142 nm kunye namandla ebhondi angama-345 kJ/mol, ebonisa uzinzo olomeleleyo ngokugqithisileyo. Ngokwahlukileyo, iiathomu zekhabhoni phakathi kweeleya ezahlukeneyo zidityaniswe ngamandla angenamandla e-van der Waals, kunye namandla okusebenzisana kuphela kwe-16.7 kJ / mol, ehambelana nesithuba esilinganisiweyo se-interplanar se-0.3354 nm. Iiyoni zeLithium zinokungena ukubuyisela umva ukufakwa kunye nokutsalwa phakathi kweengqimba zekhabhoni ezintandathu zegraphite, zenze iikhompawundi ze-LiC6 zokugcina i-lithium. Ngethuba lale nkqubo, isithuba se-interlayer sitshintsha kakhulu; kwi-LiC6, eli xabiso liba yi-0.37 nm, ngaloo ndlela kuzuzwa ubungakanani bethiyori ephezulu umthamo othe ngqo wama-372 mA·h/g. Ngaphaya koko, i-conductivity egqwesileyo yegraphite iququzelela ukufuduka kwe-electron ngokukhawuleza ngaphakathi kwemathiriyeli. Nangona kunjalo, xa isetyenziswe njengento engafanelekanga ye-electrode, i-graphite iphinda ibonise ezinye iingxaki: ukufakwa kwayo kwe-lithium ephantsi / i-extraction voltage plateau ingakhokelela ekukhuleni kwe-lithium dendrites ngexesha lokutshaja okanye ukukhupha. Nje ukuba ezi dendrites zingene kwisahluli sebhetri, zinokubangela iisekethe ezimfutshane zangaphakathi, ezinokuthi zikhokelele kwimililo okanye kuqhushumbe, okoyikise ukhuseleko lwebhetri.
Umfanekiso 5-8 Umzobo weSchematic we-graphite layered structure
Igraphite yohlulwe kakhulu ibe ziindidi ezimbini: igraphite yendalo kunye negraphite eyenziweyo. Igraphite yendalo, efinyeziweyo njenge NG (igraphite yendalo), ibhekiselele kwimathiriyeli yekhabhoni ephezulu{{1}ekhutshwe kwindalo kwaye ifunyenwe ngokucutshungulwa okulula. Inee-morphologies ezimbini ezahlukeneyo zolwakhiwo lwekristale: i-hexagonal kunye nerhombic. Esi sixhobo asininzi kuphela kwiindawo zokugcina, kodwa kunye neendleko eziphantsi kunye nokusingqongileyo. Nangona kunjalo, kwi-lithium -kusetyenziso lwebhetri ye-ion, ngenxa yokungalingani komsebenzi womphezulu kunye nobukhulu obukhulu beenkozo zamasuntswana omgubo wegraphite wendalo, ubume bayo bekristale bomhlaba wonakaliswa lula ngexesha lokuhlawulwa{6}}kumjikelezo wokukhupha, okukhokelela ekugutyungelweni kwefilimu ye-SEI engalinganiyo kunye nokuchaphazela ukusebenza kakuhle kwebhetri ye-coulombic kunye nokusebenza kwezinga. Ukoyisa le mingeni, abaphandi baye baphuhlisa iindlela ezahlukeneyo zokuphucula iipropathi zegraphite yendalo, efana ne-spheroidization, unyango lwe-oxidation surface, i-fluorination, kunye ne-carbon surface coating, ejolise ekwandiseni iimpawu zayo zomphezulu kunye ne-microstructure.
Igraphite eyenziweyo inokuveliswa-ngobushushu obuphezulu bemathiriyeli yekhabhoni eyenziwe lula. Olu hlobo lwemathiriyeli lusetyenziswa ngokubanzi njengemathiriyeli ye-anode kwiibhetri ze-lithium -. Xa kuthelekiswa negraphite yendalo, igraphite eyenziweyo ibonisa iingenelo ezibalulekileyo kubomi bomjikelo omde,{4}}umthamo wokugcina ubushushu obuphezulu, kunye{5}}nomgangatho wokusebenza okuphezulu, oko kuyenza ibe yenye yezinto ezikhethwayo ze anode yelithium{6}}ibhetri yeion esetyenziswa kwizithuthi zamandla amatsha eTshayina. Ngenxa yomthamo wayo omkhulu kunye nexabiso eliphantsi ngokwentelekiso, igraphite eyenziweyo ikwasetyenziswa kakhulu kwiibhetri zamandla kwaye phakathi{8}}ukuya{9}ukuya phezulu{10}}kwisiphelo seemveliso zombane zabathengi. Ubalo lubonisa ukuba ngo-2021, igraphite eyenziweyo yenza i-84% yazo zonke izinto ezithunyelwayo ze-anode.
Izinto ezingezizo-zekhabhoni yegraphite zohlulwe kakhulu zibe ngamacandelo amabini: ikhabhoni eqinileyo kunye nekhabhoni ethambileyo. Ikhabhoni enzima ibhekisa kuhlobo lwekhabhoni ekunzima ukuyiguqula ibe yigrafu kwisakhiwo nakwiqondo lobushushu eliphezulu kakhulu (ngaphezu kwama-2800 degrees). Ezi zixhobo zidla ngokufunyanwa nge-pyrolyzing iipolymers ezithile. Ngokukodwa, imithombo eqhelekileyo yekhabhoni enzima ibandakanya ii-resin carbons ezahlukeneyo (ezifana ne-phenolic resins, i-polyfurfuryl alcohol resin PFA-C, kunye ne-epoxy resins), ikhabhoni eyenziwe yi-pyrolysis yeepolymers ezithile (ezifana ne-polyvinyl alcohol (PVA), i-polyvinylidene fluoride (PVDF), kunye ne-polyacryle emnyama njenge-aceni ye-polyacryloni), kunye ne-polyacryle emnyama njenge-aceni. Ngexesha lenkqubo yokulungiselela, inani elikhulu le-lattice defects lenziwa ngaphakathi kwekhabhoni enzima, evumela ukuba i-lithium ion ingagcini nje ukudibanisa phakathi kweengqimba zekhabhoni kodwa iphinde igcwalise le mimandla yesiphene, ngaloo ndlela inika i-anodes eyenziwe kulo mathiriyeli umthamo ophezulu ophezulu (phakathi kwe-350 kunye ne-500 mA · b / g), enenzuzo kakhulu ekuphuculeni umthamo wonke we-lithium {9} Nangona kunjalo, iziphene ze-lattice ezikhankanywe ngasentla zikhokelela ekusebenzeni okuphantsi kwe-coulombic kunye nozinzo olubi lomjikelo xa i-carbon enzima isetyenziswa njengento ye-anode. Ukuza kuthi ga ngoku, ngenxa yezi ngxaki, ikhabhoni eqinileyo ayikasetyenziswa kakhulu kwiibhetri zeion zelithium{12}, kwaye kusekho imiqobo phambi kokuba isetyenziswe kumlinganiselo omkhulu.
Ikhabhoni ethambileyo ibhekiselele kwimathiriyeli yekhabhoni eamorphous eyenza igraphitize phantsi{0}}kweemeko zobushushu obuphezulu (ngaphezu kwama-2800 degree). Ezi zixhobo ziquka i-pitch, inaliti ye-coke, i-petroleum coke, kunye ne-carbon fibers. Ngenxa yezinga eliphantsi le-graphitization kwikhabhoni ethambileyo, isakhiwo sayo siqulethe iziphene ezininzi, ezivumela ukuba zibuyisele ukubuyisela ii-ion ze-lithium; ngaxeshanye, isithuba esikhulu se-interlayer sikhuthaza ukungena kwe-electrolyte. Ngoko ke, ngokusekelwe kwezi mpawu, izinto ezithambileyo zekhabhoni zibonisa umthamo ophezulu ngexesha lokukhutshwa kokuqala. Nangona kunjalo, kanye ngenxa yokungazinzi kwesakhiwo, amandla ayo angenakuguqulwa nawo aphakamileyo. Ngaphaya koko, ukungahambi kakuhle kolwakhiwo lwangaphakathi lwekhabhoni ethambileyo kukhokelela kulwabiwo lwamandla olwahlukeneyo lweziza ze-lithium -ezisebenzayo ze-ion, okukhokelela ekunqongophaleni kweplateau yombane echaziweyo ngexesha lokuhlawuliswa kunye nokukhutshwa, okukhawulela usetyenziso olusebenzayo.
I-Titanium dioxide
I-Titanium dioxide (TiO2) ibonisa amandla amakhulu njengento engafanelekanga ye-electrode ye-lithium -ibhetri ze-ion, kungekhona nje ngenxa yokwenzeka kwayo kwimveliso-enkulu kunye neendleko eziphantsi, kodwa nangenxa yokuba ibonisa ukhuseleko olubalaseleyo kunye nozinzo kumbane osebenzayo we-1.5V (ngokunxulumene ne-Li/Li). Ukongeza, i-TiO2 inoluhlu lweepropathi ezimangalisayo: umsebenzi ophezulu we-electrochemical, amandla e-oxidizing olomeleleyo, uzinzo olufanelekileyo lweekhemikhali, ubuninzi bemithombo yendalo, kunye nezakhiwo ezahlukeneyo zekristale.
Ezi nzuzo ngokudibeneyo zenza i-TiO2 ibe yenye yezona zinto zilungileyo zokukhetha izinto ze-electrode ze-lithium -ibhetri ze-ion (ingakumbi kwintsimi yezithuthi zombane ezixutyiweyo).
Ngokwethiyori, ubunzima beyunithi nganye ye-TiO2 inokugcina i-lithium ion enye, ehambelana nomthamo we-330 mA · h / g, ephantse iphindwe kabini umthamo wethiyori weLiTiO2. Nangona kunjalo, ekusebenzeni, kuye kwafunyaniswa ukuba ukufezekisa le ithiyori ephezulu yokugcina umthamo we-lithium kunzima kakhulu. Izinto ezininzi zichaphazela ukufakwa kwe-lithium ion kunye nokusebenza kakuhle kwe-titanium dioxide, kubandakanywa kodwa kungaphelelanga kwi-crystallinity yezinto eziphathekayo, ubungakanani beengqungquthela, iimpawu zesakhiwo sangaphakathi, kunye nommandla othile. Kuyaphawuleka ukuba i-TiO2 ikhona kwizigaba ezahlukeneyo zekristale, esona saziwa kakhulu -yintlobo ye-rutile kunye ne-anatase kwi-tetragonal crystal system, kunye nohlobo lwe-brookite kwi-orthorhombic crystal system.