A cikin tsarin caji nabatirin lithium{0}ion, Mummunan lantarki abu yana taka muhimmiyar rawa wajen ɗaukar lithium ions da electrons, kuma yana da mahimmanci don ajiyar makamashi da saki. Ta fuskar farashi, waɗannan kayan sun kai kashi 5% zuwa 15% na jimlar farashin kera batir kuma ana ɗaukarsu ɗaya daga cikin mahimman kayan albarkatun ƙasa don samar da batir lithium{3}}. Kamar ingantaccen kayan lantarki, kayan lantarki mara kyau suna taka muhimmiyar rawa wajen haɓaka ci gaban fasahar baturi na lithium{5}. A cikin 'yan shekarun nan, tare da karuwar buƙatun inganta aikin batir{7} musamman, neman mafi girman ƙarfin kuzari, ƙarfin ƙarfi, da kwanciyar hankali da tsaro mafi kyau{8}masu bincike sun mai da hankali sosai ga kayan lantarki mara kyau, ɗaya daga cikin mahimman abubuwan lithium{9}}
baturi. Kyakkyawan abu mara kyau na lantarki yakamata ya mallaki halaye masu zuwa:
(1) Mai nauyi, mai ɗaukar nauyin Li gwargwadon iyawa don haɓaka takamaiman iya aiki.
(2) Low redox yuwuwar ga lithium ion shigar da kuma hakar halayen, wanda taimaka cimma mafi girma baturi fitarwa ƙarfin lantarki.
(3) Kyakkyawan lantarki da haɓakar ionic.
(4) Rashin narkewa a cikin kaushi na electrolyte kuma baya amsawa da gishirin lithium. (5) Kyakkyawan kwanciyar hankali bayan caji da fitarwa, babban aikin aminci da rayuwar zagayowar, da ƙarancin fitar da kai{3}.
(6) Rahusa, albarkatu masu yawa, da kuma kare muhalli.
Anode materials can be divided into two main categories based on their chemical composition: carbon-based materials and non-carbon-based materials. Carbon -ana iya ƙara rarraba kayan tushen carbon zuwa kayan carbon da aka zayyana da kayan carbon amorphous. Kayayyakin da ba na -carbon - sun haɗa da silicon-based, titanium-, da ƙarfe oxides daban-daban. A halin yanzu, samfuran anode da ake amfani da su sosai a kasuwa sun haɗa da nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan suna: tushen kayan, lithium titanate (LiTisOi2), da kayan haɗin carbon da ke haɗa silicon. Carbon{14}}ana iya ƙara rarraba kayan tushen zuwa graphite (na halitta da na wucin gadi), carbon mai taushi, da kuma carbon mai wuya. Daga cikin waɗannan nau'ikan, graphite wucin gadi yana riƙe mafi girman kason kasuwa.
Abubuwan anode masu tsaka-tsaki
carbon kayan
A cikin haɓakar batirin lithium{0} ion, ƙirƙira ta amfani da kayan aikin carbon{1} don maye gurbin ƙarfe lithium kamar yadda anode ke nuna babban ci gaba a wannan fasaha. Har zuwa yau, babu wani nau'in kayan anode da zai dace da farashinsa{3}} inganci da aikin sa; don haka, ana sa ran cewa tushen carbon{4}} za su kasance zaɓi na farko don manyan aikace-aikacen kasuwanci masu girma na tsawon lokaci mai tsawo. Dangane da matakin graphitization, carbon - tushen kayan da ake amfani da su azaman anodes ana iya rarrabasu zuwa rukuni uku: graphite, carbon soft, da hard carbon. Kayayyakin carbon da ba - graphite duk suna nuna halin canzawa zuwa graphite yayin sarrafa yanayin zafi mai girma; duk da haka, wasu abubuwa sun fi dacewa da wannan canji kuma an ayyana su azaman carbon mai laushi; yayin da waɗanda ke da wahalar kammala aikin ana kiransu da ƙarfi carbon. Yawanci, ana iya samun carbon mai laushi daga albarkatun ƙasa kamar kwal ɗin kwal ko farar mai; akasin haka, carbon mai wuya galibi ana haɗe shi daga abubuwan da aka gyara kamar resin phenolic ko sucrose. A halin yanzu, daya daga cikin batutuwan da aka fi nazari a fannin carbon mai laushi shine mesophase carbon microspheres. Dukansu kayan aikin carbon mai hoto da marasa{14} suna da nasu fa'idodi da rashin amfani idan aka yi amfani da su azaman gurɓataccen lantarki a cikin batir lithium{15}}. Bisa ga wannan, masu bincike sukan yi amfani da sassa daban-daban{17} don gyarawa da canza saman waɗannan abubuwan carbon don inganta aikinsu.
Graphite, azaman kayan leda (Hoto na 5-8), yana da tsari na ciki wanda ya ƙunshi tsari mai siffar hexagonal na atom wanda aka tsara a cikin yanayin sp2, yana faɗaɗa cikin girma biyu. A cikin kowane Layer, carbon atom suna samar da ingantaccen tsarin grid hexagonal tare da nisan zarra na carbon-carbon na 0.142 nm da ƙarfin haɗin gwiwa na 345 kJ/mol, yana nuna kwanciyar hankali mai ƙarfi. Sabanin haka, carbon atoms tsakanin yadudduka daban-daban ana haɗa su ta hanyar raunanan sojojin van der Waals, tare da makamashin hulɗar kawai 16.7 kJ/mol, daidai da ma'auni na tsaka-tsakin tsaka-tsakin 0.3354 nm. Lithium ions na iya jujjuya sakawa da cirewa tsakanin nau'ikan carbon guda shida na graphite, samar da mahadi na LiC6 don adana lithium. A lokacin wannan tsari, tazarar interlayer yana canzawa sosai; don LiC6, wannan ƙimar ta zama 0.37 nm, don haka cimma iyakar ƙayyadaddun ƙayyadaddun iya aiki na 372 mA·h/g. Bugu da ƙari, ƙwaƙƙwaran ƙwaƙƙwaran graphite yana sauƙaƙe ƙaura mai sauri a cikin kayan. Duk da haka, idan aka yi amfani da shi azaman kayan lantarki mara kyau, graphite kuma yana ba da wasu kurakurai: ƙarancin shigar lithium ɗin sa / cirewar ƙarfin lantarki na iya haifar da haɓakar lithium dendrites yayin caji ko fitarwa. Da zarar waɗannan dendrites sun shiga cikin mai raba baturi, za su iya haifar da gajerun da'irori na ciki, mai yuwuwar haifar da gobara ko ma fashe, suna barazana ga amincin baturi.
Hoto 5-8 Tsarin tsari na tsarin zane mai zane
Graphite galibi ya kasu kashi biyu: graphite na halitta da graphite na wucin gadi. Halitta graphite, wanda aka gajarta a matsayin NG (na halitta graphite), yana nufin wani babban sinadarin carbon da aka ciro daga yanayi kuma ana samun shi ta hanyar sarrafawa mai sauƙi. It possesses two different morphologies of layered crystal structure: hexagonal and rhombic. Wannan abu ba wai kawai yana da yawa a cikin tanadi ba, har ma da ƙananan farashi da kuma yanayin muhalli. Duk da haka, a cikin aikace-aikacen baturi na lithium{5} ion, saboda rashin daidaituwa na aikin shimfidar wuri da babban girman hatsi na barbashi na graphite foda, tsarin sa na kristal yana samun sauƙin lalacewa yayin cajin{6}}zargin zagayowar, yana haifar da ɗaukar nauyin fim ɗin SEI mara daidaituwa kuma yana shafar ingancin coulombic na farko na baturi da ƙimar aiki. Don shawo kan wadannan kalubale, masu bincike sun ɓullo da daban-daban dabaru don inganta kaddarorin na halitta graphite, kamar spheroidization, hadawan abu da iskar shaka surface jiyya, fluorination, da kuma surface carbon shafi, da nufin inganta ta surface halaye da microstructure.
Za a iya samar da zanen wucin gadi ta hanyar zazzagewa mai girma{0}} na kayan carbon da aka zayyana cikin sauƙi. Ana amfani da irin wannan nau'in abu sosai azaman kayan anode a cikin batir lithium{2}}. Idan aka kwatanta da graphite na halitta, graphite na wucin gadi yana ba da fa'idodi masu mahimmanci dangane da tsawon rayuwar zagayowar, ƙarfin ajiya mai girma{4}, da babban aiki-, yana mai da shi ɗaya daga cikin abubuwan da aka fi so na anode don batirin lithium{6} ion da ake amfani da su a cikin sabbin motocin makamashi a China. Saboda girman ƙayyadaddun iyawarsa da ƙarancin farashi, ana kuma amfani da graphite na wucin gadi sosai a cikin batura masu ƙarfi da tsakiyar{1}zuwa{9}}ƙarshen samfuran lantarki na mabukaci. Kididdiga ta nuna cewa a cikin 2021, graphite wucin gadi ya kai kashi 84% na duk jigilar kayan anode.
Kayayyakin carbon ɗin da ba - graphite an raba shi zuwa rukuni biyu: carbon mai wuya da taushin carbon. Hard carbon yana nufin nau'in kayan carbon wanda ke da wahalar canzawa zuwa tsarin zane ko da a matsanancin yanayin zafi (sama da digiri 2800). Wadannan kayan yawanci ana samun su ta hanyar pyrolyzing wasu polymers. Musamman, hanyoyin gama gari na ƙaƙƙarfan carbon sun haɗa da carbons daban-daban na guduro (kamar phenolic resins, polyfurfuryl barasa guduro PFA-C, da epoxy resins), carbon da aka samar ta hanyar pyrolysis na takamaiman polymers (kamar polyvinyl barasa (PVA), polyvinylidene fluoride (PVDF), da kuma polyacrylonitrile baƙar fata kayayyakin (PAN) A lokacin shirye-shiryen shirye-shiryen, babban adadin lattice lahani yana samuwa a cikin carbon mai wuya, wanda ke ba da damar ions lithium ba kawai don daidaitawa tsakanin nau'in carbon ba amma har ma don cika waɗannan yankuna na lahani, don haka ba wa anodes da aka yi daga wannan kayan aiki na musamman (tsakanin 350 da 500 mA·b/g), wanda yake da amfani sosai don inganta ƙarfin lithium gaba ɗaya{9}} Koyaya, lahanin lattice ɗin da aka ambata shima yana haifar da ƙarancin ingancin coulombic na farko da rashin kwanciyar hankali lokacin da ake amfani da carbon mai ƙarfi azaman kayan anode. Ya zuwa yau, saboda waɗannan matsalolin, ba a yi amfani da ƙarfin carbon da yawa a cikin batir lithium da ake samarwa na kasuwanci ba, kuma har yanzu akwai wasu cikas kafin a yi amfani da shi a kan babban sikeli.
Carbon mai laushi yana nufin kayan carbon da ba a iya gani ba waɗanda ke yin graphitize cikin sauri a ƙarƙashin yanayin zafi mai girma{0} (sama da digiri 2800). Waɗannan kayan sun haɗa da farar, coke ɗin allura, coke na man fetur, da fiber na carbon. Saboda ƙananan matakin graphitization a cikin carbon mai laushi, tsarinsa ya ƙunshi lahani masu yawa, yana ba shi damar sake ɗaukar ƙarin ions lithium; a lokaci guda, mafi girma tazarar interlayer yana inganta shigar electrolyte. Sabili da haka, dangane da waɗannan halaye, kayan carbon mai laushi suna nuna babban ƙarfin yayin fitarwa na farko. Duk da haka, daidai saboda rashin zaman lafiyar tsarinsa, ƙarfin da ba zai iya jurewa ba shima yana da girma. Bugu da ƙari, rashin daidaituwa na tsarin ciki na carbon mai laushi yana haifar da sauye-sauyen rarraba makamashi na lithium{7} ion masu aiki da shafukan yanar gizo, yana haifar da rashin ma'anar wutar lantarki a lokacin caji da fitarwa, wanda ke iyakance aikace-aikacen sa.
Titanium dioxide
Titanium dioxide (TiO2) yana nuna babban yuwuwar azaman kayan lantarki mara kyau na baturan lithium{1}ion, ba wai kawai saboda yuwuwar sa na samarwa da yawa da ƙarancin farashi ba, amma kuma saboda yana nuna kyakkyawan aminci da kwanciyar hankali a ƙarfin ƙarfin aiki na 1.5V (dangi da Li/Li). Bugu da kari, TiO2 yana da jerin abubuwa masu ban mamaki: babban aikin electrochemical, ƙarfi mai ƙarfi mai ƙarfi, kwanciyar hankali mai kyau na sinadarai, albarkatu masu yawa, da sifofin crystal iri-iri.
Waɗannan fa'idodin tare suna sanya TiO2 ɗaya daga cikin mafi kyawun zaɓin kayan lantarki mara kyau don batirin lithium{1} (musamman a fagen motocin lantarki).
A ka'ida, kowane adadin adadin TiO2 yana iya adana ion lithium guda ɗaya, daidai da ƙarfin 330 mA·h/g, wanda kusan sau biyu ƙarfin ka'idar LiTiO2. Koyaya, a aikace, an gano cewa cimma wannan matsakaicin ƙarfin ajiyar lithium yana da wahala sosai. Abubuwa da yawa suna rinjayar shigar lithium ion shigar da haɓakar haɓakawa a cikin titanium dioxide, gami da amma ba'a iyakance ga kristal ɗin kayan ba, girman barbashi, halayen tsarin ciki, da takamaiman yanki. Yana da kyau a lura cewa TiO2 yana wanzuwa a matakai daban-daban na crystal, mafi kyawun- sananne shine nau'in rutile da anatase a cikin tsarin kristal tetragonal, da nau'in brookite a cikin tsarin crystal orthorhombic.