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Umbono: okwamanje, usawoti we-lithium ku-electrolyte yebhethri ye-lithium-ion ikakhulukazi i-LiPF6 kanye ne-LiPF6 inikeze ukusebenza kahle kwe-electrolyte kwe-electrochemical, kodwa i-LiPF6 inokunganzi kahle kokushisayo namakhemikhali, futhi izwela kakhulu emanzini.
Njengamanje, usawoti we-lithium ku-electrolyte yebhethri ye-lithium-ion ikakhulukazi i-LiPF6 kanye ne-LiPF6 inikeze ukusebenza kahle kwe-electrochemical electrolyte.Kodwa-ke, i-LiPF6 ayinakho ukuzinza kahle kwe-thermal kanye namakhemikhali, futhi izwela kakhulu emanzini.Ngaphansi kwesenzo senani elincane le-H2O, izinto ze-asidi ezifana ne-HF zizobola, bese izinto ezinhle zizogqwala, futhi izakhi zensimbi eziguquguqukayo zizoncibilika, futhi ingaphezulu le-electrode elingalungile lizothuthwa ukuze libhubhise ifilimu ye-SEI. , Imiphumela ibonisa ukuthi ifilimu ye-SEI iyaqhubeka ikhula, okuholela ekunciphiseni okuqhubekayo kwamandla amabhethri e-lithium-ion.
Ukuze unqobe lezi zinkinga, abantu baye bathemba ukuthi usawoti we-lithium we-imide one-H2O ezinzile kanye nokuzinza okungcono kwe-thermal kanye namakhemikhali, njengosawoti we-lithium njenge-LiTFSI, i-lifsi ne-lifsi, anqunyelwe yizici zezindleko kanye nama-anions we-lithium usawoti. njenge-LiTFSI ayikwazi ukuxazululwa ngokugqwala kwe-Al foil, njll., i-LiTFSI lithium salt ayisetshenziswanga ekusebenzeni.Muva nje, i-VARVARA sharova yelabhorethri yaseJalimane i-HIU ithole indlela entsha yokusetshenziswa kosawoti we-lithium imide njengezithasiselo ze-electrolyte.
Amandla aphansi we-electrode negative ye-graphite kubhethri ye-Li-ion azoholela ekuboleni kwe-electrolyte endaweni yayo, kwenze ungqimba lwe-passivation, olubizwa ngefilimu ye-SEI.Ifilimu ye-SEI ingavimbela i-electrolyte ekuboleni endaweni engeyinhle, ngakho ukuzinza kwefilimu ye-SEI kunethonya elibalulekile ekuzinzeni komjikelezo wamabhethri e-lithium-ion.Nakuba usawoti we-lithium njenge-LiTFSI ingasetshenziswa njenge-solute ye-electrolyte yokuhweba okwesikhashana, isetshenziswe njengezithasiselo futhi izuze imiphumela emihle kakhulu.Ukuhlolwa kwe-VARVARA sharova kutholwe ukuthi ukwengeza u-2wt% we-LiTFSI ku-electrolyte kungathuthukisa ngempumelelo ukusebenza komjikelezo webhethri ye-lifepo4/graphite: imijikelezo engama-600 ku-20 ℃ futhi ukwehla kwamandla kungaphansi kuka-2%.Eqenjini lokulawula, i-electrolyte ene-additive VC engu-2wt% yengezwa.Ngaphansi kwezimo ezifanayo, ukwehla komthamo webhethri kufinyelela cishe ku-20%.
Ukuze kuqinisekiswe umphumela wezithasiselo ezihlukene ekusebenzeni kwamabhethri e-lithium-ion, iqembu elingenalutho i-lp30 (EC: DMC = 1:1) ngaphandle kwezithasiselo kanye neqembu lokuhlola eline-VC, i-LiTFSI, i-lifsi ne-lifsi lilungiswe ngu-varvarvara sharova. ngokulandelana.Ukusebenza kwalawa ma-electrolyte kwahlolwa ngenkinobho uhhafu weseli neseli eligcwele.
Isibalo esingenhla sibonisa amajika e-voltammetric ama-electrolyte eqembu lokulawula elingenalutho kanye neqembu lokuhlola.Phakathi nenqubo yokunciphisa, siqaphele ukuthi inani eliphakeme lamanje elisobala livele ku-electrolyte yeqembu elingenalutho cishe ku-0.65v, elihambisana nokubola kokunciphisa kwe-solvent ye-EC.Inani eliphakeme lamanje lokubola leqembu lokuhlola elinesengezo se-VC lishintshele kumandla aphezulu, okwakungenxa yokuthi i-voltage yokubola ye-VC additive yayiphezulu kunaleyo ye-EC, Ngakho-ke, ukubola kwenzeka kuqala, okuvikele i-EC.Kodwa-ke, amajika e-voltammetric we-electrolyte engezwe nge-LiTFSI, i-lifsi kanye nezithasiselo ze-littfsi ayengafani kakhulu nalawo eqembu elingenalutho, elibonisa ukuthi izithasiselo ze-imide azikwazanga ukunciphisa ukubola kwe-solvent ye-EC.
Isibalo esingenhla sibonisa ukusebenza kwe-electrochemical kwe-graphite anode kuma-electrolyte ahlukene.Kusukela ekusebenzeni kahle kokushaja kokuqala nokukhishwa, ukusebenza kahle kwe-coulomb kweqembu elingenalutho kungu-93.3%, ukusebenza kahle kokuqala kwama-electrolyte nge-LiTFSI, i-lifsi ne-lifsi yi-93.3%, 93.6% kanye ne-93.8%, ngokulandelana.Kodwa-ke, ukusebenza kahle kokuqala kwama-electrolyte anesengezo se-VC kungama-91.5% kuphela, okubangelwa ukuthi ngesikhathi sokuqala kwe-lithium intercalation yegraphite, i-VC ibola phezu kwe-graphite anode futhi idle i-Li eyengeziwe.
Ukwakhiwa kwefilimu ye-SEI kuzoba nomthelela omkhulu ekuphatheni kwe-ionic, bese kuthinta izinga lokusebenza kwebhethri ye-Li ion.Ekuhlolweni kokusebenza kwezinga, kutholakala ukuthi i-electrolyte enezithako ze-lifsi kanye ne-lifsi inomthamo ophansi kancane kunamanye ama-electrolyte ekuphumeni okuphezulu kwamanje.Esivivinyweni somjikelezo we-C/2, ukusebenza komjikelezo wawo wonke ama-electrolyte anezithasiselo ze-imide kuzinze kakhulu, kuyilapho amandla ama-electrolyte anezithasiselo ze-VC ehla.
Ukuze kuhlolwe ukuzinza kwe-electrolyte emjikelezweni wesikhathi eside webhethri ye-lithium-ion, i-VARVARA sharova iphinde yalungisa iseli egcwele i-LiFePO4 / graphite enenkinobho, futhi yahlola ukusebenza komjikelezo we-electrolyte ngezithasiselo ezahlukene ku-20 ℃ no-40 ℃.Imiphumela yokuhlola ikhonjiswe kuthebula elingezansi.Kungabonakala etafuleni ukuthi ukusebenza kahle kwe-electrolyte enesengezo se-LiTFSI kuphezulu kakhulu kunalokho okunesengezo se-VC okokuqala ngqa, nokusebenza kwamabhayisikili ku-20 ℃ kungaphezu kwamandla.Izinga lokugcinwa komthamo we-electrolyte enesengezo se-LiTFSI ngu-98.1% ngemva kwemijikelezo engu-600, kuyilapho izinga lokugcinwa komthamo we-electrolyte enesengezo se-VC lingu-79.6 kuphela%.Kodwa-ke, le nzuzo iyanyamalala lapho i-electrolyte igijinyiswa ku-40 ℃, futhi wonke ama-electrolyte anokusebenza okufanayo kwamabhayisikili.
Kusukela ekuhlaziyeni okungenhla, akunzima ukubona ukuthi ukusebenza komjikelezo webhethri ye-lithium-ion kungathuthukiswa kakhulu lapho usawoti we-lithium imide usetshenziswa njengesengezo se-electrolyte.Ukuze kufundwe indlela yokusebenza yezithasiselo ezifana ne-LiTFSI kumabhethri e-lithium-ion, i-VARVARA sharova yahlaziya ukwakheka kwefilimu ye-SEI eyakhiwe ebusweni be-graphite anode kuma-electrolyte ahlukene nge-XPS.Isibalo esilandelayo sibonisa imiphumela yokuhlaziywa kwe-XPS yefilimu ye-SEI eyakheke ebusweni be-graphite anode ngemva komjikelezo wokuqala nowama-50.Kungabonakala ukuthi okuqukethwe kwe-LIF kufilimu ye-SEI eyenziwe ku-electrolyte ene-LiTFSI additive kuphezulu kakhulu kunalokho okuku-electrolyte ene-VC additive.Ukuhlaziywa okwengeziwe komthamo kokubunjwa kwefilimu ye-SEI kubonisa ukuthi ukuhleleka kokuqukethwe kwe-LIF kufilimu ye-SEI lithi lifsi > liftfsi > LiTFSI > VC > iqembu elingenalutho ngemva komjikelezo wokuqala, kodwa ifilimu ye-SEI ayiguquki ngemva kokukhokhiswa kokuqala.Ngemuva kwemijikelezo engu-50, okuqukethwe kwe-LIF kwefilimu ye-SEI ku-lifsi ne-liftfsi electrolyte kwehle ngo-12% no-43%, ngokulandelana, kuyilapho okuqukethwe kwe-LIF kwe-electrolyte engezwe nge-LiTFSI kukhuphuke ngo-9%.
Ngokuvamile, sicabanga ukuthi ukwakheka kolwelwesi lwe-SEI luhlukaniswe izingqimba ezimbili: ungqimba lwangaphakathi lwe-inorganic kanye nolwendlalelo lwezinto eziphilayo lwangaphandle.Isendlalelo sezinto ezingaphili ngokuyinhloko sakhiwe i-LIF, i-Li2CO3 nezinye izakhi ze-inorganic, ezinokusebenza okungcono kwe-electrochemical kanye ne-ionic conductivity ephakeme.Isendlalelo sangaphandle sezinto eziphilayo ngokuyinhloko sakhiwe ngokubola kwe-electrolyte enezimbotshana kanye nemikhiqizo ye-polymerization, njenge-roco2li, i-PEO njalonjalo, engenakho ukuvikeleka okuqinile kwe-electrolyte, Ngakho-ke, sithemba ukuthi ulwelwesi lwe-SEI luqukethe izingxenye ezingaphili.Izithasiselo ze-Imide zingaletha ezinye izingxenye ze-LIF ezingaphili kulwelwesi lwe-SEI, okwenza ukwakheka kolwelwesi lwe-SEI kuzinze, kungavimbela kangcono ukubola kwe-electrolyte kumjikelezo webhethri, kunciphise ukusetshenziswa kwe-Li, futhi kuthuthukise kakhulu ukusebenza komjikelezo webhethri.
Njengezithasiselo ze-electrolyte, ikakhulukazi izithasiselo ze-LiTFSI, i-lithium salts ingathuthukisa kakhulu ukusebenza komjikelezo webhethri.Lokhu kubangelwa ikakhulukazi ukuthi ifilimu ye-SEI eyakhiwe ebusweni be-graphite anode ine-LIF eyengeziwe, ifilimu encane futhi ezinzile ye-SEI, enciphisa ukubola kwe-electrolyte futhi inciphise ukumelana nesixhumi esibonakalayo.Nokho, kusukela kudatha yokuhlola yamanje, okungeziwe kwe-LiTFSI kufaneleka kakhulu ukusetshenziswa ekamelweni lokushisa.Ku-40 ℃, isengezo se-LiTFSI asinanzuzo esobala kunesengezo se-VC.
Isikhathi sokuthumela: Apr-15-2021