◆Ingxubevange{0}}yohlobo lwezinto ze-anode
◆Ukuguqulwa{0}}kohlobo lwezinto ze-anode
◆Izinto ze-lithium metal anode
Enqubweni yokushaja yeamabhethri e-lithium-ion, i-electrode engalungile idlala indima ebalulekile ekuphatheni i-lithium ion nama-electron, futhi ibalulekile ekugcineni amandla nokukhululwa. Ngokombono wezindleko, lezi zinto zokusebenza zenza u-5% kuya ku-15% wesamba sezindleko zokukhiqiza ibhethri futhi zibhekwa njengenye yezinto ezibalulekile ezibalulekile zokukhiqiza ibhethri ye-lithium{3}}i-ion. Njengempahla ye-electrode ephozithivu, okokusebenza kwe-electrode okunegethivu kudlala indima ebaluleke kakhulu ekukhuthazeni intuthuko yobuchwepheshe bebhethri ye-lithium-ion. Eminyakeni yakamuva, ngenxa yesidingo esikhulayo sokusebenza kwebhethri okuthuthukisiwe{7}}ikakhulukazi, ukuphishekela ukuminyana kwamandla okuphezulu, ukuminyana kwamandla, nokuzinza okungcono komjikelezo nokuphepha{8}}abacwaningi banake kakhulu impahla ye-electrode eyinegethivu, enye yezingxenye eziyinhloko ze-lithium{9}}
amabhethri. Into efanelekile ye-electrode engafanele kufanele ibe nalezi zimpawu ezilandelayo:
(1) I-Lightweight, ethatha i-Li eningi ngangokunokwenzeka ukuze ikhulise umthamo othize.
(2) Amandla aphansi e-redox okufakwa kwe-lithium ion kanye nokusabela kokukhipha, okusiza ukuzuza amandla aphezulu okukhipha ibhethri.
(3) I-electronic conductivity enhle ne-ionic.
(4) Ayincibiliki kuma-electrolyte solvents futhi ayiphenduli ngosawoti we-lithium. (5) Ukuzinza kwamakhemikhali okuhle kakhulu ngemva kokushaja nokukhipha, ukusebenza kokuphepha okuphezulu nempilo yomjikelezo, kanye nezinga lokuzikhipha{3} eliphansi.
(6) Izinsizakusebenza ezingabizi, eziningi, futhi azihambisani nemvelo.
Izinto ze-anode zingahlukaniswa zibe izigaba ezimbili eziyinhloko ngokusekelwe ekwakhekeni kwamakhemikhali: izinto ezisekelwe kukhabhoni{{0}ezisekelwe ku-carbon{1}}nezinto ezingasekelwe{1}}zekhabhoni{2}. Izinto ezisekelwe kukhabhoni{4} zingaphinde zihlukaniswe zibe izinto zekhabhoni yesithombe nezinto zekhabhoni ye-amorphous. Izinto ezingasekelwe ku-{{6}carbon{7}}zibandakanya i-silicon{8}based, titanium{{9}based, kanye nama-metal oxides ahlukahlukene. Okwamanje, izinto ezisetshenziswa kakhulu ze-anode emakethe ikakhulukazi zihlanganisa izinhlobo ezintathu:{11}}izinto ezisekelwe kukhabhoni, i-lithium titanate (LiTisOi2), kanye nezinto eziyinhlanganisela yekhabhoni ehlanganisa i-silicon. Izinto ezisekelwe kukhabhoni{14} zingahlukaniswa futhi zibe igraphite (i-graphite yemvelo neyokwenziwa), i-soft carbon, ne-hard carbon. Phakathi kwalezi zigaba, i-graphite yokwenziwa ibamba isabelo semakethe esikhulu kunazo zonke.
Izinto ezihlanganisiwe ze-anode
izinto zekhabhoni
Ekuthuthukisweni kwamabhethri e-lithium-e-ion, ukusungulwa okusha kokusebenzisa{1}izinto ezisekelwe kukhabhoni ukuze kuthathelwe indawo i-lithium eyinsimbi njengoba i-anode iphawula impumelelo enkulu kulobu buchwepheshe. Kuze kube manje, alukho olunye uhlobo lwento ye-anode engafana nezindleko zayo-ukusebenza nokusebenza kwayo; ngakho-ke, kulindelekile ukuthi izinto ezisekelwe kukhabhoni{4}zizohlala ziyinketho eyinhloko-yezicelo zokuthengisa ezinkulu isikhathi eside. Ngokusekelwe kuzinga le-graphitization,{7}izinto ezisekelwe kukhabhoni{7}ezisetshenziswa njengama-anode zingahlukaniswa zibe izigaba ezintathu: igraphite, i-soft carbon, ne-hard carbon. Izinto ezingezona-ezingezona zekhabhoni ye-graphite zonke zibonisa ukuthambekela kokuguquka zibe i-graphite phakathi{10}}nokucubungula izinga lokushisa eliphezulu; nokho-ke, ezinye izinto zithambekele kakhulu kulolu shintsho futhi zichazwa njengekhabhoni ethambile; kuyilapho lezo ezinzima ukuqedela inqubo zibizwa ngokuthi i-hard carbon. Ngokuvamile, ikhabhoni ethambile ingatholakala ezintweni ezingavuthiwe njengetiyela lamalahle noma i-petroleum pitch; ngokuphambene, ikhabhoni eqinile isetshenziswa kakhulu ezingxenyeni ezifana ne-phenolic resin noma i-sucrose. Njengamanje, esinye sezifundo ezifundwe kakhulu emkhakheni wekhabhoni ethambile i-mesophase carbon microspheres. Kokubili izinto ezisetshenziswayo ze-graphitic nengezona{14}}zekhabhoni ye-graphitic zinezinzuzo zazo kanye nokubi lapho zisetshenziswa njengama-electrode angemuhle kumabhethri e-lithium{15}}e-ion. Ngokusekelwe kulokhu, abacwaningi bavame ukusebenzisa{17}}amasegimenti amancane ukuze balungise futhi baguqule indawo yalezi zinto ezisetshenziswayo zekhabhoni ukuze bathuthukise ukusebenza kwazo.
I-graphite, njengento enezingqimba (Umfanekiso 5-}8), inesakhiwo sangaphakathi esihlanganisa uhlaka lwe-athomu olunezinhlangothi ezine ezihlelwe kusimo esiyingxube se-sp2, esinwebeka ngobukhulu obubili. Ngaphakathi kwesendlalelo ngasinye, ama-athomu ekhabhoni akha ukwakheka kwegridi eyi-hexagonal eqinile enebanga le-athomu le-carbon-carbon elingu-0.142 nm namandla ebhondi angu-345 kJ/mol, abonisa ukuzinza okuqine kakhulu. Ngokuphambene, ama-athomu ekhabhoni phakathi kwezendlalelo ezihlukene axhunywe amandla abuthaka e-van der Waals, anamandla okusebenzisana angu-16.7 kJ/mol kuphela, ahambisana nesikhala esilinganiselwe se-interplanar esingu-0.3354 nm. Ama-ion e-lithium angafakwa ngokuphindisela emuva futhi akhishwe phakathi kwezingqimba zekhabhoni eziyisithupha zegraphite, enze izinhlanganisela ze-LiC6 zokugcina i-lithium. Phakathi nale nqubo, ukuhlukaniswa kwe-interlayer kushintsha kakhulu; ku-LiC6, leli nani liba ngu-0.37 nm, ngaleyo ndlela kuzuzwe umthamo othize omkhulu othize ongu-372 mA·h/g. Ngaphezu kwalokho, i-conductivity ye-graphite enhle kakhulu yenza kube lula ukufuduka kwama-electron ngaphakathi kwempahla. Kodwa-ke, lapho isetshenziswa njengento engalungile ye-electrode, i-graphite iphinde iveze ezinye izithiyo: ukufakwa kwayo okuphansi kwe-lithium / ukukhishwa kwe-voltage plateau kungaholela ekukhuleni kwe-lithium dendrites ngesikhathi sokushaja noma ukukhulula. Uma lawa ma-dendrite engene kusihlukanisi sebhethri, angabangela amasekhethi amafushane angaphakathi, okungenzeka aholele emlilweni noma ngisho nokuqhuma, okusongela ukuphepha kwebhethri.
Umfanekiso 5-8 Umdwebo weSchematic wesakhiwo se-graphite layered
I-graphite ihlukaniswe ngokuyinhloko izigaba ezimbili: i-graphite yemvelo kanye ne-graphite yokwenziwa. I-graphite yemvelo, efushanisiwe ngokuthi NG (i-graphite yemvelo), isho-into ekhabhoni ephezulu ekhishwe emvelweni futhi etholakala ngokucubungula okulula. Inama-morphologies amabili ahlukene wesakhiwo sekristalu enezingqimba: i-hexagonal ne-rhombic. Lezi zinto azigcini nje ngokuchichima ezindaweni ezigciniwe, kodwa futhi ziphansi ngezindleko futhi azihambisani nemvelo. Nokho, ezinhlelweni zebhethri ye-lithium-ion, ngenxa yokusatshalaliswa okungalingani komsebenzi ongaphezulu kanye nosayizi omkhulu wokusanhlamvu wezinhlayiya zempushana ye-graphite yemvelo, ukwakheka kwayo kwekristalu engaphezulu konakaliswa kalula phakathi nokushajwa-kumijikelezo yokukhipha, okuholela ekumbozweni kwefilimu ye-SEI engalingani futhi kuthinte ukusebenza kahle kwebhethri kokuqala kanye nokusebenza kwezinga. Ukuze banqobe lezi zinselele, abacwaningi baye bahlakulela izindlela ezihlukahlukene zokuthuthukisa izakhiwo ze-graphite yemvelo, njenge-spheroidization, i-oxidation surface treatment, fluorination, kanye ne-surface carbon coating, okuhloswe ngayo ukuthuthukisa izici zayo ezingaphezulu kanye ne-microstructure.
I-graphite yokwenziwa ingakhiqizwa-i-graphitization yezinga lokushisa eliphezulu yezinto ezisetshenziswa kalula zekhabhoni eyi-graphitized. Lolu hlobo lwento lusetshenziswa kakhulu njenge-anode kumabhethri e-lithium-i-ion. Uma kuqhathaniswa ne-graphite yemvelo, i-graphite yokwenziwa ibonisa izinzuzo ezibalulekile mayelana nempilo yomjikelezo omude,{4}}umthamo wokugcina wezinga lokushisa eliphezulu, -nokusebenza kwezinga eliphezulu, okuyenza ibe enye yezinto ezikhethwayo ze-anode zamabhethri e-lithium{6}}ion asetshenziswa ezimotweni zamandla amasha e-China. Ngenxa yomthamo wayo omkhulu othize kanye nezindleko eziphansi uma kuqhathaniswa, i-graphite yokwenziwa iphinde isetshenziswe kabanzi kumabhethri anamandla futhi maphakathi-naphakathi{{9}kumikhiqizo{10}}yaphezulu{10}}yabathengi bama-electronics. Izibalo zibonisa ukuthi ngo-2021, i-graphite yokwenziwa yabalelwa ku-84% wakho konke ukuthunyelwa kwe-anode.
Izinto ezingezona-zekhabhoni ye-graphite zihlukaniswa kakhulu zibe izigaba ezimbili: i-hard carbon ne-soft carbon. I-Hard carbon ibhekisela ohlotsheni lwe-carbon material okunzima ukuyishintsha ibe isakhiwo se-graphite ngisho namazinga okushisa aphakeme kakhulu (ngaphezu kuka-2800 degree). Lezi zinto zivame ukutholwa nge-pyrolyzing ama-polymers athile. Ikakhulukazi, imithombo evamile yekhabhoni eqinile ihlanganisa ama-resin carbons ahlukahlukene (njengama-phenolic resins, polyfurfuryl alcohol resin PFA-C, nama-epoxy resins), ikhabhoni eyakhiwe yi-pyrolysis yama-polymers athile (njenge-polyvinyl alcohol (PVA), i-polyvinylidene fluoride (PVDF), kanye nemikhiqizo ye-polyacryle black efana ne-polyacryloni emnyama efana ne-acetyloni emnyama). Phakathi nenqubo yokulungiselela, inani elikhulu lamaphutha e-lattice kwakheka ngaphakathi kwekhabhoni eqinile, evumela ama-ion e-lithium ukuthi angagcini nje ngokuhlangana phakathi kwezingqimba zekhabhoni kodwa futhi agcwalise lezi zindawo ezinesici, ngaleyo ndlela inikeze ama-anode enziwe kusuka kulokhu okubalulekile umthamo othize ophezulu (phakathi kuka-350 no-500 mA·b/g), okuzuzisa kakhulu ekuthuthukiseni umthamo wonkana wamabhethri e-lithium{9}. Kodwa-ke, ukukhubazeka kwe-lattice okukhulunywe ngenhla nakho kuholela ekusebenzeni kahle kokuqala kwe-coulombic kanye nokungaqini kahle komjikelezo lapho i-carbon eqinile isetshenziswa njengento ye-anode. Kuze kube manje, ngenxa yalezi zinkinga, ikhabhoni eqinile ayikasetshenziswa kakhulu kumabhethri e-lithium{12}}e-ion akhiqizwa ukuthengisa, futhi kusenezithiyo ezithile ngaphambi kokuthi isetshenziswe ngezinga elikhulu.
Ikhabhoni ethambile isho okubalulekile kwekhabhoni ye-amorphous ekwazi ukwenza i-graphitize ngaphansi-izimo zezinga lokushisa eliphezulu (ngaphezulu kuka-2800 degree). Lezi zinto zifaka i-pitch, inaliti ye-coke, i-petroleum coke, ne-carbon fibers. Ngenxa yezinga eliphansi le-graphitization kukhabhoni ethambile, ukwakheka kwayo kuqukethe iziphambeko eziningi, okusivumela ukuthi ikwazi ukubuyisela emuva ama-ion e-lithium amaningi; kanyekanye, isikhala esikhulu se-interlayer sikhuthaza ukungena kwe-electrolyte. Ngakho-ke, ngokusekelwe kulezi zici, izinto ezithambile zekhabhoni zibonisa umthamo omkhulu ngesikhathi sokukhishwa kokuqala. Kodwa-ke, ngenxa yokungaqini kwesakhiwo sayo, amandla ayo angenakuhlehliswa nawo aphakeme uma kuqhathaniswa. Ngaphezu kwalokho, ukungahambi kahle kwesakhiwo sangaphakathi sekhabhoni ethambile kuholela ekusabalaliseni amandla okuhlukahluka kwamasayithi e-lithium-i-ion asebenzayo, okuholela ekuntulekeni kwe-voltage plateau echaziwe ngesikhathi sokushaja nokukhipha, okukhawulela ukusetshenziswa kwayo okungokoqobo.
I-Titanium dioxide
I-Titanium dioxide (i-TiO2) ibonisa amandla amakhulu njenge-electrode engasebenzi kahle yamabhethri e-lithium-e-ion, hhayi nje ngenxa yokuba nokwenzeka kwayo-ekukhiqizeni okukhulu nezindleko eziphansi, kodwa futhi ngenxa yokuthi ibonisa ukuphepha okuhle kakhulu nokuzinza ku-voltage yokusebenza engu-1.5V (ehlobene ne-Li/Li). Ngaphezu kwalokho, i-TiO2 inochungechunge lwezakhiwo eziphawulekayo: ukusebenza okuphezulu kwe-electrochemical, amandla aqinile e-oxidizing, ukuqina okuhle kwamakhemikhali, imithombo yemvelo eningi, nezinhlaka zekristalu ezinhlobonhlobo.
Lezi zinzuzo ngokuhlangene zenza i-TiO2 ibe enye yezinketho ezinhle kakhulu ze-electrode engalungile yamabhethri e-lithium-i-ion (ikakhulukazi emkhakheni wezimoto zikagesi eziyingxubevange).
Ngokwethiyori, iyunithi lesisindo seyunithi ngayinye ye-TiO2 ingagcina i-lithium ion eyodwa, ehambelana nomthamo ongu-330 mA·h/g, ocishe uphindwe kabili umthamo wetiyori we-LiTiO2. Kodwa-ke, ekusebenzeni, kutholakale ukuthi ukufeza lo mthamo wokugcina we-lithium wethiyori kunzima impela. Izinto eziningi zithonya ukufakwa kwe-lithium ion nokusebenza kahle kokukhipha ku-titanium dioxide, okuhlanganisa kodwa kungagcini nje ngokucwebezela kwezinto, usayizi wezinhlayiyana, izici zesakhiwo sangaphakathi, nendawo ethile. Kubalulekile ukuqaphela ukuthi i-TiO2 ikhona ngezigaba ezihlukahlukene zekristalu,{6}eyaziwa kakhulu izinhlobo ze-rutile ne-anatase kusistimu yekristalu ye-tetragonal, kanye nohlobo lwe-brookite kusistimu ye-orthorhombic crystal.