Uhlolojikelele Lokuhlaziywa Kokuhluleka kanye Nendlela Yephutha Yebhethri ye-Lithium Ion

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Ukukhiqizwa nokukhula kwefilimu ye-1SEI kusistimu yebhethri ye-lithium-ion yezentengiselwano, futhi ingxenye yokulahlekelwa amandla ebhethri isuka ohlangothini oluphakathi kwegraphite ne-organic electrolyte, futhi i-graphite isabela kalula nge-electrochemically nge-lithium ion organic electrolyte, ikakhulukazi i-Solvent i-vinyl carbonate (EC) ne-dimethyl carbonate (DMC). Lapho ibhethri ye-lithium ion iphakathi nokushaja kokuqala (isiteji), i-electrolyte eyinegethivu kanye ne-lithium ion electrolyte kwenzeka futhi i-lithium ion electrolyte yenzeka futhi ungqimba lwefilimu eqinile ye-electrolyte interface (SEI) yakheka endaweni yegraphite, engabangela ingxenye yomthamo ongabuyiseleki emuva. Ifilimu ye-SEI iqinisekisa ukudluliswa kwama-ion ngenkathi ivikela into esebenzayo, futhi ivimbela ukuzinza kokusebenza kwento esebenzayo yento esebenzayo yebhethri kuyilapho kuvimbela into esebenzayo.

Kodwa-ke, phakathi nomjikelezo olandelayo webhethri, njengoba ukunwetshwa njalo nokufinyezwa kwempahla ye-electrode kubangela isayithi entsha esebenzayo ukuthi iveze, lokhu kungabangela indlela yokwehluleka kokulahlekelwa okuqhubekayo, okungukuthi, umthamo webhethri wehliswa ngokuqhubekayo. Lo mshini wokungaphumeleli ungabangelwa inqubo yokunciphisa i-electrochemical ebusweni be-electrode, evezwa njengokwanda okuqhubekayo kogqinsi lwefilimu ye-SEI. Ngakho-ke, ukutadisha izingxenye zamakhemikhali zefilimu ye-SEI kanye ne-morphology kungaba ngokujulile, imbangela yomthamo webhethri ye-lithium-ion kanye nokwehla kwamandla.

Inqubo yokwakhiwa kwefilimu ye-SEI Eminyakeni yamuva nje, abacwaningi bazamile ukutadisha ubunjalo bolwelwesi lwe-SEI ngokuhlakaza izivivinyo zamasistimu amabhethri amancane. Inqubo yokuhlakaza ibhethri yenziwa ebhokisini legilavu ​​yegesi ye-aerosolic inert ( <5 ppm). After the battery is disassembled, it can pass a nuclear magnetic resonance technology (NMR), a flight time secondary ion mass spectrometry (TEMS), a scanning electron microscope (SEM), a transmission electron microscope (TEM), an atomic force microscope (AFM), X-ray absorption spectrum (XAF), and Infrared (FTIR) and Raman Spectroscopy and other test methods study the thickness, morphology, composition, growth process and mechanism of SEI membranes.

Nakuba izindlela eziningi zokuhlola ziye zasetshenziswa ukuze kubonakale ifilimu ye-SEI, imodeli yangempela yefilimu ye-SEI ikhula ebhethrini isetshenziselwa ukubonisa izindlela ezithuthuke kakhulu neziqondile. Ubunzima ukuthi ifilimu ye-SEI iyinkimbinkimbi ngezinto ezihlukahlukene ezifana ne-organic and inorganic, futhi isithako siyinkimbinkimbi, futhi sintekenteke kakhulu futhi kulula ukuphendula emvelweni. Uma kungalungile, kunzima ukuthola ulwazi lweqiniso lwefilimu ye-SEI.

Ukuqina kwefilimu ye-SEI kuwukusabela okujwayelekile kwe-electrochemical parasitic side, enobudlelwane obuseduze ne-reaction kinetics, inqubo yokudlulisa ngobuningi, kanye ne-structural geometry yebhethri. Kodwa-ke, ukuguqulwa kwefilimu ye-SEI akuholeli ngokuqondile ekuhlulekeni kokuhluleka okulimazayo, futhi ukubola kwayo kuzokwenza kuphela ukwanda kokushisa kwangaphakathi kwebhethri, okungabangela ukubola kwegesi, futhi ukushisa okukhulu kuzobangela ukuphuma kokushisa. Ku-FMMEA, ukwakheka nokukhula kwefilimu ye-SEI kubhekwa njengendlela yokulahlekelwa, engabangela ibhethri ukunciphisa umthamo futhi ikhulise i-impedance yangaphakathi.

2 I-Lithium dendrites ikhiqiza, uma ibhethri ishajwa ngokushesha ekumineni kwamanje okungaphezulu kwamanje okulinganiselwe, futhi indawo enegethivu yakheka kalula ukuze yakhe i-lithium dendride yensimbi. Le crystal ye-dendritic kulula ukubhoboza i-diaphragm, ibangele ukujikeleza okufushane ngaphakathi kwebhethri. Lesi simo singase sibangele ukwehluleka ukucekelwa phansi kwebhethri, futhi kunzima ukubona ngaphambi kokuba ibhethri libe yimfushane.

Eminyakeni yamuva, abacwaningi bafunde izinga lokukhula kwe-lithium dendride kanye nobudlelwano phakathi kwezinga lokukhula kwe-lithium dendrites kanye nomthamo we-lithium ion wokusabalalisa we-lithium dendrites. Ukuhlola kubonisa ukuthi ukukhula kwe-lithium delegra kunzima ukukubona noma ukuqaphela ohlelweni oluphelele lwebhethri, futhi imodeli yamanje ikhawulelwe ekukhuleni kwe-lithium dendrites ngaphansi kwesistimu eyodwa. Kuhlelo lokuhlola, ibhethri elibonisa ngale elakhiwe ingilazi ye-quartz lingakwazi ukubona inqubo yokukhula ye-lithium dendrites in situ.

Umcwaningi we-Zhang Yuegono e-Suzhou Nanotechnology kanye ne-Nano Bionic Research Institute ezweni lami uveze inqubo yokwakheka kobuchwepheshe be-lithium dendrites (njengoba buboniswa yividiyo) kubuchwepheshe be-electron microscope (SEM) yokuskena. Kodwa-ke, ohlelweni lwebhethri ye-lithium-ion yokuhweba, kunzima ukufeza ukubonwa kwangempela kwamagatsha e-lithium. Isimo sendawo yonke ukubuka amakristalu egatsha le-lithium ngokudiliza ibhethri.

Kodwa-ke, ngenxa yokuthi umsebenzi wegatsha le-lithium uphakeme kakhulu, kunzima ukuhlaziya imininingwane yesizukulwane. Zier et al. Kuhlongozwe ukudweba ama-electron micrograms e-electrode ngokudaya isakhiwo se-electrode ukuze kunqunywe indawo yama-dendrites.

Uma ngaphambi kokuhlakazwa kwebhethri, isizukulwane se-lithium branch crystal siye sabangela ukujikeleza okufushane kwangaphakathi ngaphakathi, khona-ke le ngxenye ye-dendritic crystal ingase ibe nzima ukuyiqaphela ngoba i-pulse current enkulu yesifunda esifushane sangaphakathi ingabangela i-crystallization yegatsha le-lithium. Ukuvalwa kwe-microporous yendawo ye-diaphragm kuphakamisa ukuthi indawo yokukhula okungenzeka ye-lithium dendrites, kodwa lezi zingxenye zingase zishise ngokweqile noma zibangelwa ukungcola kwensimbi. Ngakho-ke, ukuthuthukiswa okuqhubekayo kwamamodeli okuhluleka ukubikezela ukuvela kwamagatsha e-lithium, futhi ngesikhathi esifanayo, kunenjongo kakhulu ukutadisha ubuhlobo bokuphila nokwehluleka ngaphansi kwezimo ezahlukene zokusebenza.

3 I-pollization yezinhlayiya zezinto ezisebenzayo azilingani ekukhishweni kokushaja okusheshayo nokukhipha noma into esebenzayo ye-electrode, into esebenzayo ijwayele ukuba yimpushana noma ukuhlukana. Ngokuvamile, njengoba ibhethri inwetshiwe, izinhlayiya ze-micron-size, ukucindezeleka kwangaphakathi kwe-ion kungase kuphulwe. Ukuqhekeka kokuqala kungabonwa yi-SEM ebusweni bezinhlayiya zezinto ezisebenzayo.

Njengoba ukushumeka okuphindaphindiwe kwe-lithium ion, imifantu iqhubeka ikhula, okuholela ekuqhekekeni kwezinhlayiya. Izinhlayiya eziqhekekayo zizodalula indawo entsha esebenzayo, futhi ifilimu ye-SEI ikhiqizwa endaweni entsha. Ngokucwaninga nokuhlaziywa kwengcindezi ye-lithium ion yokushumeka, ukwakheka okungcono kwezinto ze-electrode zebhethri.

UChristensen noNewman et al. Kuthuthukiswe imodeli yokuqala ye-lithium-ion eshumekiwe yokucindezeleka, futhi abanye abacwaningi bandise izinto ezihlukahlukene, kanye ne-geometric morphology yezinto zokwakha, nezinto zokwakha. Imodeli yokucindezeleka eshumekiwe ye-Ion izosiza abacwaningi ukuthi baklame izinto ezisebenza kakhulu.

Kodwa-ke, ukulahlekelwa amandla namandla ezinhlayiya zezinto ezisebenzayo kuqhutshekwa kufunda, futhi indlela yokuhluleka kokuhlukana kwezinhlayiyana ibikezelwa ngokugcwele ukubikezela impilo yamabhethri e-lithium-ion. Ukuguqulwa kwevolumu yezinto ze-electrode kungabangela futhi into esebenzayo ukuthi ilayishwe nomqoqi wamanje, ukuze le ngxenye yento esebenzayo ingatholakali. Inqubo ye-lithium ehlanganisiwe yezinto ezisebenzayo ihambisana nokufuduka kwe-ion kanye nokufuduka kwe-electron yangaphandle ngaphakathi kwebhethri.

Njengoba i-electrolyte ifakwe ngogesi, ama-ion kuphela anganikezwa. Ukuziphatha kwama-electron kubalulekile kunethiwekhi ye-conductive eyakhiwe indawo ye-electrode yi-agent conductive. Izinguquko ezivamile kumthamo wezinto ze-electrode zingabangela izinto ezisebenzayo eziyingxenye ezivela kunethiwekhi ye-conductive ukuze zenze uhlelo oluzimele, olungatholakali.

Lolu shintsho esakhiweni se-electrode lungalinganiswa ngokulinganisa indlela efana ne-porosity noma indawo ethile. Le nqubo ingaphinda igaywe ngokugaywa kwendawo ye-electrode kusetshenziswa i-focal ion beam (FIB), kusetshenziswa i-SEM ukwenza ukuhlola kwe-morphological noma i-X-ray tomography test usebenzisa i-SEM. Izinto ze-electrode ezingalungile ziyahlanzwa futhi zikhishwe kunethiwekhi ye-conductive.

I-electrode esebenzayo esebenzayo yento esebenzayo ye-electrode esebenzayo iningi i-transition metal oxide, njenge-lithium cobaltate (LiMn2O4), noma usawoti we-polyanate Lithium, i-lithium iron phosphate (LifePo4). Iningi lezinto ezisebenzayo ezinhle izindlela zokusabela ezishumekiwe, futhi izindlela zabo zokucindezeleka kanye nezindlela zokuwohloka komnotho ikakhulukazi ngenxa yokuwa kwama-granules kanye nencazelo yezinto ezisebenzayo ngenhla. Ifilimu ye-SEI iphinde ikhiqizwe futhi ithinteke ebusweni be-electrode enhle, kodwa ubuso be-electrode enhle bunamandla amakhulu, futhi ifilimu yayo ye-SEI incane kakhulu futhi izinzile.

Ngaphezu kwalokho, izinto ezibonakalayo ze-electrode nazo ziyakwazi ukuthonywa yithonya lokukhiqiza ukushisa kwangaphakathi, ikakhulukazi uma ibhethri ligcwele isihlalo. Ngesikhathi sokushaja, i-electrolyte iba engazinzi ngaphansi kwengcindezi ephezulu, okuholela ku-electrolyte kanye nento esebenzayo ye-electrode, ebangela ukuthi izinga lokushisa langaphakathi lebhethri liqhubeke likhuphuka, kanye nezinto ezibonakalayo ze-electrode zikhipha umoya-mpilo. Ukuthuthukisa okuqhubekayo, okuholela ekungalawuleni okushisayo, kuzodala ukuhluleka kokucekelwa phansi kwebhethri.

Okubalulekile kwe-electrode eyenzeka ngesikhathi sokushajwa kwangaphambili kungahlaziywa nge-chromatography yegesi ukuze kuhlaziywe noma kutholwe ukwakheka kwempahla ye-electrode ngesakhiwo se-X-ray spectrum yokuthola i-electrode. Nokho, okwamanje ayikho imodeli yokwehluleka engabikezela ingaphakathi lebhethri ngokuchichima kwegesi eshajwe ngokweqile. Isifinyezo: Imodi yokuhluleka kwebhethri ye-lithium-ion yezinto ezibonakalayo ze-electrode e-lithium-ion ibalulekile ekwakhiweni kwe-membrane ye-SEI, ukukhiqizwa kwekristalu ethunyelwe i-lithium noma amakristalu e-copperprine, impushana yezinhlayiya zezinto ezisebenzayo kanye negesi yokubola ukushisa, njll.

Phakathi kwabo, isizukulwane se-lithium derivatives noma i-copper delegths, igesi yokubola kwezinto ezibonakalayo ibangelwa kalula ukushisa okushisayo kweseli, okubangela ukusha kwebhethri, ngisho nokuqhuma. Ukwehluleka kwamabhethri e-lithium-ion kuhlaziywa imodi ephelile, futhi indlela ilungiswa ngokuthuthukisa impahla yebhethri, ukwakheka, nokuthuthukisa ukuguquguquka kwemvelo, ukwethembeka nokuphepha kwebhethri. Ngakho-ke, kunokubaluleka kokuqondisa okubaluleke kakhulu ekukhiqizeni nasekusetshenzisweni okungokoqobo kwebhethri.