Uhlalutyo lwesizathu sohlalutyo lwe-lithium yebhetri yokunciphisa amandla

Umbhali :Iflowpower-Umboneleli weSikhululo saMandla esiphathwayo

Kwibhetri ye-ion ye-lithium, ibhalansi yomthamo ibonakaliswa njengomlinganiselo wobunzima be-electrode eyakhayo kwi-electrode engalunganga, eyile:γ= m + / m- =δXC- /δI-YC + ifomula ephezulu C ibhekisa kumthamo wethiyori we-coulomb ye-electrode,δencinci,δI-Y ibhekisela kwi-chemical metering ye-lithium ion efakwe kwi-electrode engafanelekanga kunye ne-electrode efanelekileyo. Inokubonwa kule fomyula ingentla ukuba ubungakanani bobunzima beepali ezimbini buxhomekeke kwinani le-coulomb umthamo kunye ne-lithium ion eguqukayo ngokuhambelana nezibonda ezimbini. Ngokuqhelekileyo, umlinganiselo omncinci wobunzima ubangela ukusetyenziswa okungaphelelanga kwezinto ze-electrode ezimbi; umlinganiselo omkhulu wobunzima unokuba nobungozi bokhuseleko ngenxa ye-electrode engalunganga ebekwe ngaphezulu kwesitulo.

Ngamafutshane, kowona mlinganiselo uphuculweyo womgangatho, ukusebenza kwebhetri kugqibelele. Inxulumene nenkqubo yebhetri ye-Li-ION efanelekileyo, kwixesha layo lokujikeleza, ubuninzi bomxholo awutshintshi, kwaye umthamo wokuqala kumjikelezo ngamnye uxabiso elithile, kodwa imeko yangempela inzima kakhulu. Nayiphi na impendulo esecaleni enokuthi ibonakale okanye idle i-ion ze-lithium okanye ii-electron zingabangela utshintsho kwi-balance balance umthamo webhetri, emva kokuba ibhalansi yamandla ebhetri yenzeke, olu tshintsho alunakuguqulwa, kwaye lunokuqokelela ngemijikelezo emininzi, kwaye ukusebenza kwebhetri kwenzeka.

Impembelelo enzulu. Ukongeza, ngaphandle kokugcinwa kwe-oxidation ye-ion ye-lithium, kukho inani elikhulu leempendulo zecala, ezifana nohlalutyo lwe-electrolyte, ukuchithwa kwezinto ezisebenzayo, ukuchithwa kwe-metal lithium, njl. ihlawuliswa kakhulu, i-ion ye-lithium iyancitshiswa ngokulula kwindawo engafanelekanga: i-lithium egciniweyo ihlanganiswe ne-negative surface, ivimba i-lithium embedding.

Ukusebenza kokukhutshwa kuncitshisiwe kunye nokulahlekelwa kwamandla, i-original: i-1 inokunciphisa i-lithium ye-cyclic; I-2 ifakwe i-lithium yensimbi kunye ne-solvent okanye i-electrolyte yokuxhasa ukwenza i-Li2CO3, i-LIF okanye ezinye iimveliso; I-3 yensimbi ye-lithium idla ngokuqulunqwa phakathi kwe-electrode engafanelekanga kunye ne-diaphragm, mhlawumbi I-pores ye-diaphragm yokuthintela yandisa ukuchasana kwangaphakathi kwebhetri; Ukutshaja ngokukhawuleza, ukuxinana okukhulu kwangoku, i-polarization embi kakhulu, ukubekwa kwe-lithium kuya kucaca ngakumbi. Le meko kulula ukwenzeka kwisihlandlo se-electrode engalunganga esebenzayo.

Nangona kunjalo, kwimeko yezinga eliphezulu lokutshaja, ukufakwa kwe-lithium yensimbi kunokwenzeka nokuba umlinganiselo we-electrode efanelekileyo kunye ne-negative esebenzayo yinto eqhelekileyo. 2, impendulo echanekileyo echanekileyo iphantsi kakhulu xa i-electrode esebenzayo yokuxhathisa iphantsi kakhulu, kwaye kulula ukuyibiza. Utshintsho oluhle lubangela ukulahlekelwa kwamandla ngenxa yokwenzeka kwezinto ze-electrochemical inert (ezifana ne-CO3O4, MN2O3, njl.

), ephazamisa ukulingana kwamandla phakathi kwe-electrodes, kunye nokulahlekelwa kwayo kwamandla akunakubuyiselwa. (1) liycoo2liycoo2→(1-y) / 3 [CO3O4 + O2 (G)] + Ylicoo2Y<0.4 Simultaneous positive electrode material analyzes oxygen in a sealed lithium ion battery to analyze the oxygen due to the absence of re-reactive reaction (such as the formation of H2O) and the combustible gas in the electrolyte analysis At the same time, the consequences will be unimaginable.

(2)λ-MnO2 lithium manganese reaction yenzeka kwimeko apho i-lithium manganese oxide idecentre ngokupheleleyo:λ-Mno2→Mn2O3 + O2 (G) 3, i-electrolyte i-oxidized xa i-electrolyte i-oxidized xa uxinzelelo luphezulu kune-4.5V, kunye ne-electrolyte (umz.

, Li2CO3) kunye negesi i-oxidized, kwaye ezi zinto zingaxutywanga ziya kuthintela i-micropores ye-electrode. Ukufuduka kwe-lithium ion kubangela ukulahlekelwa kwamandla ngexesha lokujikeleza. Ukuchaphazela umlinganiselo wezinga le-oxidation: Uhlobo kunye nobukhulu bommandla wendawo ye-agent conductive (carbon black, njl.

) idityaniswe yinto efanelekileyo ye-electrode yezinto eziphathekayo kwindawo yokuqokelela ubungakanani (ikhabhoni emnyama, njl.njl.) kwisisombululo se-electrolytic esisetyenziswa ngoku, i-EC / DMC ithathwa njengowona mandla aphezulu oxidation. Inkqubo ye-electrochemical oxidation yesisombululo ibonakaliswa ngokubanzi njenge: isisombululo→Iimveliso ze-oxidation (iigesi, izisombululo kunye nezinto eziqinileyo) + NE-nayiphi na i-oxidation ye-solvent inokunyusa ukuxinwa kwe-electrolyte, ukuzinza kwe-electrolyte kuyancipha, kwaye umthamo webhetri ekugqibeleni.

Masithi utya indawo encinci ye-electrolyte ngalo lonke ixesha itshajiswa, ngoko ke i-electrolyte eninzi ikwindibano yebhetri. Kwizikhongozeli eziqhubekayo, oku kuthetha ukuba inani elincinci lezinto ezisebenzayo lilayishiwe, okuya kubangela ukuhla kwamandla okuqala. Ukuqhubela phambili, ukuba imveliso eyomeleleyo iyenzeka, ifilimu ye-passivation yenziwa kumphezulu we-electrode, eya kubangela ukuba ibhetri inyuse amandla ombane webhetri.

I-2 yokuqala: I-Electrolyte (Ukubuyisela kwakhona) I Kuhlalutyo lwe-electrode 1 Ukunciphisa umthamo webhetri, ukusabela kokunciphisa i-electrolyte ngokuchasene nomthamo webhetri kunye nobomi obujikelezayo kuya kuchaphazela kakubi, kwaye ngenxa yokunciphisa igesi ukunyusa ibhetri, ngaloo ndlela kukhokelela kukhuseleko. imiba. I-voltage yokuhlalutya i-electrode echanekileyo idla ngokuba nkulu kune-4.5V (enxulumene ne-Li / Li +), ngoko akulula ukuyihlalutya kwizinto ezilungileyo.

Kunoko, i-electrolytes iyahluka kakhulu ukuhlalutya. I-2, i-electrolyte ihlalutywa kwi-electrode engalunganga: i-electrolyte ayikho phezulu kwigraphite kunye nezinye i-pithonal carbon negatives, kwaye kulula ukusabela ukuba ayinakuguqulwa. Uhlalutyo lwesisombululo se-electrolytic ngexesha lokuhlawula okuphambili kunye nokukhutshwa kuya kwenza ifilimu ye-passivation ebusweni be-electrode, kwaye ifilimu ye-passivation inokuthintela uhlalutyo olongezelelweyo lwe-electrolyte kunye ne-carbon negative electrode.

Ngaloo ndlela, ukuzinza kwesakhiwo se-carbon negative electrode kugcinwa. Ngokufanelekileyo, ukunciphisa i-electrolyte kunqunyelwe kwisigaba sokubunjwa kwefilimu ye-passivation, kwaye inkqubo ayisekho xa umjikelezo uzinzile. Ukunciphisa ukubunjwa kwetyuwa ye-electrolyte yefilimu ye-passivation ibandakanyeka ekubunjweni kwefilimu ye-passivation, eququzelela ukuzinza kwefilimu ye-passivation, kodwa izinto ezichithwayo ezincitshisiweyo kwi-solvent zichaphazeleka kakubi yimveliso yokunciphisa i-solvent. ; (2) Ukunciphisa ityuwa ye-electrolyte Ukuxinwa kwesisombululo se-electrolytic kwancitshiswa, kwaye ekugqibeleni kubangele amandla ebhetri (ukunciphisa i-LiPF6 ukuvelisa i-LIF, i-LiXPF5-X, i-PF3O kunye ne-PF3); (3) Ukuqulunqwa kwefilimu ye-passivation kukusebenzisa i-lithium ion, enokubangela ukuba umthamo we-polar ungalingani.

Ibhetri yonke iyancipha. (4) Ukuba kukho ukuqhekeka kwifilimu ye-passivation, i-molecule ye-solvent ingatshintshelwa ukwenza ifilimu ye-passivation igxininise, engayisebenzisi kuphela i-lithium eninzi, kodwa iyakwazi ukuvala i-micropores phezu kwekhabhoni, okubangela i-lithium. ayikwazi kuzinziswa kwaye ikhutshwe Isiphumo sokuphulukana nesakhono esingenakubuyiseka. Yongeza ezinye izongezo ze-inorganic, ezifana ne-CO2, N2O, CO, SO2, njl.

, inokukhawulezisa ukubunjwa kwefilimu ye-passivation, kwaye inokuthintela isimboli kunye nohlalutyo lwe-solvent, kunye nokongezwa kwesithsaba se-ether organic additive inefuthe elifanayo, apho i-12 isithsaba i-4 ether ingcono kakhulu. Izinto ezibangela ukulahlekelwa kwamandla okwenza ifilimu: (1) Uhlobo lwekhabhoni; (2) izithako ze-electrolyte; (3) izongezo kwi-electrode okanye i-electrolyte. I-BLYR ikholelwa ukuba i-ion exchange reaction iqhubela phambili ukusuka kumphezulu wezinto ezisebenzayo ukuya kumbindi wayo, isigaba esitsha esakhiweyo singcwatywa, kwaye umphezulu wamasuntswana wenza i-ion ephantsi kunye ne-electron conductivity, ngoko ke i-spinel emva kokugcinwa.

I-polarization engaphezulu kunokugcinwa. I-ZHANG ifumanisa ukuchithwa okuthelekisayo kwe-AC impedance spectrum ngaphambi nangemva kwezinto ze-electrode, kunye nenani elitsha lemijikelezo, ukuchasana komgangatho we-surface passivation kuye kwanda, kwaye i-interface capacitance iyancitshiswa. Ukubonakaliswa kobunzima bomgca we-passivation wongezwa kunye nenani lemijikelo.

Ukuchithwa kwe-manganese kunye nokuhlalutya kwe-electrolyte kubangela ukubunjwa kwefilimu ye-passivation, kunye neemeko eziphezulu zokushisa zilungele ngakumbi ezi mpendulo. Oku kuya kubangela ukuchasana okungathanga ngqo kwezinto ezisebenzayo kunye nokunyuka kwe-Li + yokufuduka kwe-migration, ngaloo ndlela kwandisa i-polarization yebhetri, kwaye umrhumo kunye nokukhutshwa akuphelelanga, kwaye umthamo uyancitshiswa. Isisombululo se-II electrolytic reductant mechanism ye-electrolyte ihlala iqulethe ukungcola okunje ngeoksijini, amanzi, ikharbon diokside, kunye neempendulo ze-oxidative zenzeka ngexesha lebhetri kunye nenkqubo yokukhupha.

Indlela yokunciphisa i-electrolyte ibandakanya ukunciphisa i-solvent, ukunciphisa i-electrolyte kunye nokunciphisa ukungcola iinkalo ezintathu: i-1, ukunciphisa i-PC yokunciphisa i-solvent kunye ne-EC ibandakanya ukusabela kwe-electron kwinkqubo yesibini yokusabela kwe-elektroniki, iifom ze-electron yesibini ze-Li2CO3: i-FONG, njl. ., okokuqala Ngexesha lenkqubo yokukhupha, amandla e-electrode asondele kwi-O.8V (vs.

li / li +), i-PC / EC ivelisa i-electrochemical reaction kwi-graphite, ivelisa i-CH = CHCH3 (G) / CH2 = CH2 (G) kunye ne-LiCO3 (s) , Okubangela ukulahlekelwa kwamandla okungenakuguqulwa kwi-electrode yegraphite. I-Aurbach et al kwiindidi ezininzi zokunciphisa i-electrolyte kunye neemveliso zayo kwi-metal lithium electrode kunye ne-carbon-based electrode, yafumanisa ukuba i-RocO2Li kunye nepropylene yenzeke kwi-electronic reaction mechanism ye-PC. I-Roco2li inochuku kakhulu ekulandeleni amanzi.

Imveliso eqinile yiLi2CO3 kunye nepropylene, kodwa akukho Li2CO3 kwimeko yokomisa. U-Ein-Eliy wabika ukuba i-electrolyte eyenziwe nge-diethyl carbonate (DEC) kunye ne-diomethymethane (DMC), i-reaction reaction iyenzeka kwibhetri, kwaye i-methyl carbonate (EMC) yenziwe, kwaye kukho ukulahleka okuthile kokulahlekelwa kwamandla. Impembelelo.

I-2, i-reaction yokunciphisa i-electrolyte yokunciphisa i-electrolyte ngokuqhelekileyo ithathwa njengebandakanyeka ekubunjweni kwendawo ye-carbon electrode, kwaye ngoko ke, iindidi kunye nokugxininiswa kwayo kuya kuchaphazela ukusebenza kwe-carbon electrode. Kwezinye iimeko, ukuncitshiswa kwe-electrolyte kunegalelo ekuzinzeni kwendawo yekhabhoni, kwaye kunokwenza umaleko ofunekayo wokudlula. Ngokuqhelekileyo kukholelwa ukuba i-electrolyte exhasayo ilula ukunciphisa kune-solvent, kunye nokufakwa kwemveliso yokunciphisa kwifilimu egciniweyo ye-electrode kwaye ichaphazela amandla okunciphisa ibhetri.

Iimpendulo ezininzi zokunciphisa ezixhasa i-electrolytes zinokuthi zenzeke ngolu hlobo lulandelayo: 3, umxholo wamanzi ekunciphiseni ukungcola (1) Umthamo wamanzi kwi-electrolyte uya kuvelisa i-LiOH (S) kunye ne-Li2O ye-deposition layers, engahambelani ne-lithium ion embedding, eyenza ilahleko yesakhono engenakubuyiseka: H2O + E→OH- + 1 / 2H2OH- + Li +→LiOH (s) LiOH + Li ++ E-→I-Li2O (S) + 1 / 2H2 ivelisa i-LiOH (S) yokubeka umphezulu we-electrode, yenza ifilimu enkulu yomhlaba enokumelana okukhulu, ukuthintela i-electrode ye-graphite efakwe kwi-Li +, ebangela ukulahlekelwa kwamandla okungenakuguquleka. Amanzi aphakathi kwi-solvent (100-300×10-6) Akukho mpembelelo ekusebenzeni kwe-graphite electrode. (2) I-CO2 kwi-solvent ingancitshiswa kwi-electrode engafanelekanga ukwenza i-CO kunye ne-LiCO3 (S): 2CO2 + 2E- + 2LI +→I-Li2CO3 + COCO iya kwandisa ibhetri kwibhetri, ngelixa i-Li2CO3 (S) ikwandisa ukuxhathisa ibhetri kwandisa ukusebenza kwebhetri.

(3) Ubukho be-oksijini kwi-solvent nayo yenza i-Li2O ngenxa yokuba umehluko onokuthi ubekhona phakathi kwe-lithium yensimbi kunye nekhabhoni ye-lithium ehambelana ngokupheleleyo incinci, kwaye ukunciphisa i-electrolyte kwikhabhoni kufana nokunciphisa i-lithium. Ekuqaleni 3: Ukuzikhupha ngokwakho kuthetha ukuba ibhetri ilahlekile ngokwendalo kwimeko engasetyenziswanga. I-lithium-ion ibhetri yokuzikhupha iphumela kwiimeko ezimbini: enye ilahleko yomthamo obuyiselwayo; okwesibini kukuphulukana nomthamo ongenakuguqulwa.

Ukulahleka kwamandla okubuyisela ukubuyisela kuthetha ukuba amandla okulahleka anokubuyiswa ngexesha lokutshaja, kwaye ilahleko yexabiso elingaguqukiyo iguqulwa, kwaye i-electrode efanelekileyo nengalunganga ingasetyenziselwa ukusetyenziswa kweeseli ezincinci kunye ne-electrolyte kwimeko yokutshaja, kwaye I-lithium ion ifakwe kwaye ilahliwe, i-positive kunye ne-negative embeding kwaye ivaliwe. I-lithium ions efakwe kuphela ihambelana ne-lithium ion ye-electrolyte, kwaye amandla e-electrode afanelekileyo kunye ne-negative ngoko ke ayilingani. Le nxalenye yelahleko yomthamo ayinakufunyanwa kwakhona xa kutshaja.

Ezinje: I-lithium manganese oxide i-electrode e-positive kunye ne-solvent inokuvelisa ukuzikhupha okubangelwa kukuzikhupha: iimolekyuli ezinyibilikayo (umzekelo, i-PC) zixutywe njengeeseli ze-microbial kumphezulu we-carbon dioxide emnyama okanye ulwelo lwangoku: okufanayo, i-electrode engalunganga into esebenzayo Inokuzikhupha ngokwayo kwisisombululo se-electrolytic ukuya kwi-electrolyte, kunye ne-electrolyte (efana ne-LiPF6) iyancipha yi-electrolyte (efana ne-LiPF6).

I-lithium ion isuswa kwi-electrode engalunganga ye-microcontroller njenge-electrode engafanelekanga yemo yokutshaja: Ukuzikhupha Izinto: Inkqubo yokuvelisa izinto ezintle ze-electrode, inkqubo yokuvelisa ibhetri, iipropati ze-electrolyte, ukushisa, ixesha. Izinga lokuzikhupha lilawulwa ngokuqinileyo ngesantya se-oxidation ye-solvent, ngoko ukuzinza kwe-solvent kuchaphazela ubomi bokugcinwa kwebhetri. I-oxidation ye-solvent yenzeke kumphezulu wekhabhoni emnyama, kwaye indawo emnyama yekhabhoni inokulawula izinga lokuzikhupha, kodwa kwi-LIMN2O4 yezinto eziphathekayo ze-electrode, ukunciphisa indawo engaphezulu yezinto ezisebenzayo nazo ziqinile, kwaye umphezulu wangoku wokuqokelela ujongene nokusetyenziswa kwe-oxidation ye-solvent ayinakungahoywa.

Ikhoyo ngoku evuzayo yi-diaphragm yebhetri inokubangela ukuzikhupha kwibhetri ye-lithium ion, kodwa inkqubo inqunyelwe ukuxhathisa kwe-diaphragm, kwizinga eliphantsi kakhulu, kwaye ayinanto yakwenza nobushushu. Ukuqwalasela ukuba izinga lokuzikhupha kwebhetri lithembele kakhulu kwiqondo lokushisa, le nkqubo ayikho indlela ebalulekileyo ekuzikhupheni. Ukuba i-electrode engalunganga ikwimeko yombane owaneleyo, iziqulatho zebhetri ziyatshatyalaliswa, okuya kubangela ukulahleka kwamandla ngokusisigxina.