Iibhetri zeLithium ziya kudibana neemeko ezahlukeneyo ngexesha lokusetyenziswa kwazo. Ebusika, iqondo lobushushu kumantla eTshayina lidla ngokuba ngaphantsi kwe-0℃ okanye nokuba -10℃. Xa ukutshaja kunye nokukhutshwa kweqondo lokushisa kwebhetri kuthotywa ngaphantsi kwe-0 ℃, ukutshaja kunye nokukhupha umthamo kunye ne-voltage yebhetri ye-lithium iya kuncipha ngokukhawuleza. Oku kungenxa yokuba ukuhamba kwee-ion ze-lithium kwi-electrolyte, i-SEI kunye neengqungquthela zegraphite ziyancipha kwiqondo lokushisa eliphantsi. Ubume obunjalo beqondo lokushisa eliphantsi ngokuqinisekileyo luya kukhokelela kwimvula yentsimbi ye-lithium enendawo ethile ephezulu.

Imvula yeLithium enendawo ethile ephezulu ephezulu sesinye sezona zizathu zibalulekileyo zokusilela kwebhetri ye-lithium, kunye nengxaki ebalulekileyo yokhuseleko lwebhetri. Oku kungenxa yokuba inendawo enkulu kakhulu, isinyithi se-lithium sisebenza kakhulu kwaye sinokutsha, indawo ephakamileyo ye-dendrite lithium yincinci yomoya omanzi unokutshiswa.

Ngokuphuculwa komthamo webhetri, uluhlu kunye nesabelo semarike yezithuthi zombane, iimfuno zokhuseleko lwezithuthi zombane ziya ziba nzima ngakumbi. Ziziphi iinguqu ekusebenzeni kweebhetri zamandla kumaqondo aphantsi? Yeyiphi imiba yokhuseleko efanele ukuqwalaselwa?

I-1.18650 i-cryogenic cycle experiment kunye nohlalutyo lokuchithwa kwebhetri

Ibhetri ye-18650 (2.2A, NCM523/ graphite system) iye yalinganiswa kubushushu obuphantsi obuyi-0℃ phantsi kwendlela ethile yokukhupha intlawulo. Indlela yokutshaja kunye nokukhupha i-charge yile: i-CC-CV yokutshaja, isantya sokutshaja yi-1C, i-voltage yokutshaja esikiweyo yi-4.2V, i-cutting off current yokutshaja yi-0.05c, emva koko i-CC ikhuphe ukuya kwi-2.75V. Njengoko ibhetri ye-SOH ye-70% -80% ngokuqhelekileyo ichazwa njengemeko yokupheliswa (EOL) yebhetri. Ngoko ke, kolu vavanyo, ibhetri iyanqanyulwa xa i-SOH yebhetri i-70%. Umjikelo webhetri phantsi kweemeko ezingentla uboniswe kuMfanekiso 1 (a). Uhlalutyo lwe-Li MAS lwe-NMR lwenziwa kwiipali kunye ne-diaphragms yeebhetri ezijikelezayo nezingajikeleziyo, kwaye iziphumo zokufuduswa kweekhemikhali ziboniswe kuMfanekiso 1 (b).

Umzobo 1. Ijika lomjikelo weseli kunye nohlalutyo lwe-Li MAS NMR

Umthamo womjikelezo we-cryogenic wanda kwimijikelezo embalwa yokuqala, elandelwa ukuhla ngokukhawuleza, kwaye i-SOH yehla ngaphantsi kwe-70% ngaphantsi kwemijikelezo ye-50. Emva kokuqhawula ibhetri, kwafunyaniswa ukuba kukho umaleko wesilivere-grey kwi-anode, ekucingelwa ukuba yintsimbi ye-lithium efakwe kumphezulu we-anode ejikelezayo. Uhlalutyo lwe-Li MAS lwe-NMR lwenziwa kwiibhetri zamaqela amabini okuthelekisa okulinga, kwaye iziphumo zaqinisekiswa ngakumbi kuMfanekiso B.

Kukho incopho ebanzi kwi-0ppm, ebonisa ukuba i-lithium ikhona kwi-SEI ngeli xesha. Emva komjikelezo, i-peak yesibini ibonakala kwi-255 PPM, enokuthi yenziwe yimvula yensimbi ye-lithium ebusweni bezinto ze-anode. Ukuqinisekisa ngakumbi ukuba i-lithium dendrites ibonakala ngokwenene, i-SEM morphology yabonwa, kwaye iziphumo ziboniswe kuMfanekiso 2.

Umfanekiso

Umzobo 2. Iziphumo zohlalutyo lwe-SEM

Ngokuthelekisa imifanekiso A kunye no-B, kunokubonwa ukuba ungqimba olungqindilili lwento lwenziwe kumfanekiso B, kodwa olu luhlu aluzange luwagubungele ngokupheleleyo amasuntswana egraphite. Ukwandiswa kwe-SEM kwandiswa ngakumbi kwaye inaliti efana neyona nto yabonwa kuMzobo D, onokuthi ube yi-lithium enendawo ethile ephezulu (eyaziwa ngokuba yi-dendrite lithium). Ukongeza, i-lithium metal deposition ikhula ngokubhekiselele kwi-diaphragm, kwaye ubukhulu bayo bunokubonwa ngokuthelekisa kunye nobukhulu be-graphite layer.

Ifom ye-lithium efakwe kuxhomekeke kwizinto ezininzi. Njengokuphazamiseka komphezulu, ukuxinana kwangoku, imeko yokutshaja, ubushushu, izongezo ze-electrolyte, ukubunjwa kwe-electrolyte, i-voltage esetyenzisiweyo njalo njalo. Phakathi kwazo, ukujikeleza kweqondo lokushisa eliphantsi kunye noxinzelelo oluphezulu lwangoku yeyona nto ilula kakhulu ukwenza isinyithi esixineneyo se-lithium kunye nommandla othile ophezulu.

2. Uhlalutyo lokuzinza kwe-thermal ye-electrode yebhetri

I-TGA yayisetyenziselwa ukuhlalutya ii-electrode zebhetri ezingajikelezikanga kunye nasemva kokujikeleza, njengoko kubonisiwe kuMfanekiso 3.

Umfanekiso

Umzobo 3. Uhlalutyo lwe-TGA yee-electrode ezimbi kunye ne-positive (A. I-electrode engafanelekanga B. I-electrode enhle)

Njengoko kunokubonwa kulo mzobo ungentla, i-electrode engasetyenziswanga ineencopho ezintathu ezibalulekileyo kwi-T≈260℃, 450℃ kunye ne-725℃ ngokulandelanayo, ebonisa ukuba ukubola okunobundlobongela, ukuvela komphunga okanye ukuphendulwa kwe-sublimation kwenzeka kwezi ndawo. Nangona kunjalo, ilahleko enkulu ye-electrode yayicacile kwi-33 ℃ kunye ne-200 ℃. Ukusabela kokubola kwiqondo lokushisa eliphantsi kubangelwa ukubola kwe-membrane ye-SEI, ngokuqinisekileyo, inxulumene nokubunjwa kwe-electrolyte kunye nezinye izinto. Imvula yensimbi ye-lithium eneendawo eziphezulu eziphezulu ezikhokelela ekubunjweni kwenani elikhulu leefilimu ze-SEI kumphezulu we-lithium metal, ekwasisizathu sokulahleka kweebhetri phantsi komjikelo wobushushu obuphantsi.

I-SEM ayikwazanga ukubona naluphi na utshintsho kwi-morphology yezinto ze-cathode emva kovavanyo lwe-cyclic, kwaye uhlalutyo lwe-TGA lubonise ukuba kukho ukulahleka komgangatho ophezulu xa izinga lokushisa lingaphezulu kwe-400 ℃. Le lahleko yobunzima inokubangelwa kukunciphisa i-lithium kwizinto ze-cathode. Njengoko kuboniswe kuMfanekiso 3 (b), ngokuguga kwebhetri, umxholo we-Li kwi-electrode enhle ye-NCM iyancipha kancane kancane. Ilahleko enkulu ye-SOH100% ye-electrode esebenzayo yi-4.2%, kwaye leyo ye-SOH70% ye-electrode efanelekileyo yi-5.9%. Ngelizwi, izinga lokulahleka kobunzima bezo zombini ii-electrode ezintle kunye nezibi zonyuka emva komjikelezo we-cryogenic.

3. Uhlalutyo lokuguga kwe-Electrochemical ye-electrolyte

Impembelelo yobushushu obuphantsi kwi-electrolyte yebhetri yahlalutywa yiGC/MS. Iisampulu ze-Electrolyte zithathwe kwiibhetri ezingagugi kunye nezidala ngokulandelanayo, kwaye iziphumo zohlalutyo lweGC / MS ziboniswe kuMfanekiso 4.

Umfanekiso

Umzobo 4.GC/MS kunye neziphumo zovavanyo lwe-FD-MS

I-electrolyte yebhetri ye-non-cryogenic cycle iqulethe i-DMC, i-EC, i-PC, kunye ne-FEC, i-PS, kunye ne-SN njenge-admixtures yokuphucula ukusebenza kwebhetri. Ubungakanani be-DMC, i-EC kunye ne-PC kwiseli engajikeleziyo kunye neseli ejikelezayo iyafana, kunye ne-additive SN kwi-electrolyte emva kokujikeleza (ethintela ukubola kwe-electrode electrolytic liquid oksijini ephantsi kombane ophezulu) iyancitshiswa. , ngoko ke isizathu kukuba i-electrode efanelekileyo ihlawuliswa ngokuyinxenye phantsi komjikelo wobushushu obuphantsi. I-BS kunye ne-FEC yi-SEI ifilimu eyenza izongezo, ezikhuthaza ukusekwa kweefilimu ze-SEI ezizinzileyo. Ukongeza, i-FEC inokuphucula ukuzinza komjikelo kunye nokusebenza kakuhle kweCoulomb yeebhetri. I-PS inokunyusa ukuzinza kwe-thermal ye-anode SEI. Njengoko kunokubonwa kumfanekiso, inani le-PS alinciphi ngokuguga kwebhetri. Kwakukho ukuhla okubukhali kwinani le-FEC, kwaye xa i-SOH yayingu-70%, i-FEC yayingenakubonwa. Ukunyamalala kwe-FEC kubangelwa ukuhlaziywa okuqhubekayo kwe-SEI, kunye nokuvuselelwa ngokuphindaphindiweyo kwe-SEI kubangelwa imvula eqhubekayo yeLi kwi-cathode graphite surface.

Imveliso ephambili ye-electrolyte emva komjikelezo webhetri yi-DMDOHC, i-synthesis yayo ihambelana nokubunjwa kwe-SEI. Ngoko ke, inani elikhulu le-DMDOHC kwi-FIG. I-4A ithetha ukusekwa kweendawo ezinkulu ze-SEI.

4. Uhlalutyo lokuzinza kwe-thermal yeebhetri ze-non-cryogenic cycle

Iimvavanyo ze-ARC (i-Accelerated calorimeter) zenziwa kwi-non-cryogenic cycle kunye neebhetri ze-cryogenic cycle phantsi kweemeko ze-quasi-adiabatic kunye nemodi ye-HWS. Iziphumo ze-Arc-hws zibonise ukuba i-exothermic reaction yabangelwa ngaphakathi kwebhetri, ngaphandle kobushushu be-ambient yangaphandle. Indlela esabela ngayo ngaphakathi kwebhetri inokohlulwa ngokwezigaba ezithathu, njengoko kubonisiwe kwiTheyibhile yoku-1.

Umfanekiso

Ukufunxa ngokuyinxenye kobushushu kwenzeka ngexesha le-diaphragm thermalization kunye nogqabhuko-dubulo lwebhetri, kodwa i-diaphragm thermalization ayihoywa kuyo yonke i-SHR. Ukusabela kokuqala kwe-exothermic kuvela ekuboleni kwe-SEI, kulandelwa kukufakwa kwe-thermal ukubangela ukuchithwa kwe-lithium ion, ukufika kwee-electron kumphezulu wegraphite, kunye nokunciphisa i-electrons ukuseka kwakhona i-membrane ye-SEI. Iziphumo zovavanyo lokuzinza kwe-thermal ziboniswa kuMfanekiso 5.

Umfanekiso

Umfanekiso

Umzobo 5. Iziphumo ze-Arc-hws (a) 0%SOC; (b) i-SOC yama-50 ekhulwini; (c) I-100 leepesenti le-SOC; Imigca edawuniweyo yiqondo lobushushu lokuqala le-exothermic reaction, iqondo lobushushu lokuqala lokubaleka kunye nobushushu obubalekayo bobushushu.

Umfanekiso

Umfanekiso 6. Arc-hws isiphumo sokutolika a. Iqondo lobushushu lokubaleka, iB.ID yokuqalisa, C. Ubushushu bokuqala bokubaleka kwe-thermal d. Ubushushu bokuqala bokusabela kwe-exothermic

I-exothermic reaction yokuqala (OER) yebhetri ngaphandle komjikelo we-cryogenic iqala malunga ne-90℃ kwaye inyuke ngokulandelelana ukuya kwi-125℃, ngokuncipha kwe-SOC, ebonisa ukuba i-OER ixhomekeke kakhulu kwimeko ye-lithium ion kwi-anode. Kwibhetri kwinkqubo yokukhupha, i-SHR ephezulu (izinga lokuzifudumeza) kwi-reaction yokubola yenziwa malunga ne-160 ℃, kwaye i-SHR iya kuncipha kwiqondo lokushisa eliphezulu, ngoko ke ukusetyenziswa kwee-ion ze-lithium ezidibeneyo kuchongwa kwi-electrode engalunganga. .

Ngethuba nje kukho i-lithium ions eyaneleyo kwi-electrode engafanelekanga, kuqinisekisiwe ukuba i-SEI eyonakalisiweyo inokwakhiwa kwakhona. Ukuchithwa kwe-thermal yezinto ze-cathode kuya kukhulula i-oksijini, eya kuthi i-oxidize kunye ne-electrolyte, ekugqibeleni iholele ekuziphatheni kwe-thermal runaway yebhetri. Ngaphantsi kwe-SOC ephezulu, izinto ze-cathode zikwisimo esiphezulu se-delithium, kwaye isakhiwo se-cathode sesona sixhobo sisisigxina. Yintoni eyenzekayo kukuba ukuzinza kwe-thermal yeseli kuncipha, inani le-oksijini ekhutshweyo liyenyuka, kwaye ukusabela phakathi kwe-electrode efanelekileyo kunye ne-electrolyte ithatha kwiqondo lokushisa eliphezulu.

4. Ukukhutshwa kwamandla ngexesha lokuvelisa igesi

Ngohlalutyo lwebhetri yasemva komjikelo, kunokubonwa ukuba i-SHR iqala ukukhula kumgca othe ngqo malunga ne-32℃. Ukukhutshwa kwamandla kwinkqubo yokuvelisa igesi ikakhulu kubangelwa ukusabela kokubola, ngokuqhelekileyo kuthathwa njengokuchithwa kwe-thermal ye-electrolyte.

Isinyithi se-lithium esinendawo ethile ephakamileyo ephezulu sinyuka kumphezulu wezinto ze-anode, ezinokubonakaliswa ngolu hlobo lulandelayo.

Umfanekiso

Kupapasho, i-Cp sisixhobo sobushushu esikhethekileyo, kwaye △T imele isixa sokunyuka kobushushu bebhetri okubangelwa kukubola kovavanyo lwe-ARC.

Amandla obushushu obuthile beeseli ezingajikeleziswanga phakathi kwe-30 ℃ kunye ne-120℃ zavavanywa kwimifuniselo ye-ARC. Ukusabela kwe-exothermic kwenzeka kwi-125 ℃, kwaye ibhetri ikwimo yokukhupha, kwaye akukho mpendulo ye-exothermic iphazamisana nayo. Kolu vavanyo, i-CP inobudlelwane bomgca kunye nobushushu, njengoko kubonisiwe kule nxaki ilandelayo.

Umfanekiso

Isixa esipheleleyo samandla esikhutshwe kwi-reaction yonke sinokufunyanwa ngokudibanisa umthamo wobushushu obuthile, obuyi-3.3Kj ngokuguga kweseli kumaqondo aphantsi. Ubungakanani bamandla akhutshiweyo ngexesha lokubaleka kwe-thermal alikwazi ukubalwa.

5. Umfuniselo weacupuncture

Ukuze kuqinisekiswe impembelelo yokuguga kwebhetri kuvavanyo lwesekethe emfutshane yebhetri, ulingo lwenaliti lwenziwa. Iziphumo zovavanyo ziboniswe kumzobo ongezantsi:

Umfanekiso

Ngokubhekiselele kwisiphumo se-acupuncture, u-A bubushushu bomphezulu webhetri ngexesha lenkqubo ye-acupuncture, kwaye i-B lelona qondo lobushushu liphezulu elinokufikelelwa.

Inokubonwa kumzobo ukuba kukho umehluko omncinci we-10-20 ℃ phakathi kwebhetri yokuguga emva kokukhutshwa kunye nebhetri entsha (i-SOC 0%) ngovavanyo lokudinga. Kwiseli elidala, ubushushu obupheleleyo bufikelela kwi-T≈35℃ phantsi kwemeko ye-adiabatic, ehambelana ne-SHR≈0.04K/min.

Ibhetri engasebenziyo ifikelela kubushushu obuphezulu be-120℃ emva kwemizuzwana engama-30 xa iSOC ingama-50%. Ubushushu bejoule obukhutshiweyo akwanelanga ukufikelela kweli qondo lobushushu, kwaye i-SHR idlula umlinganiselo wokusasazwa kobushushu. Xa i-SOC i-50%, ibhetri yokuguga inefuthe elithile lokulibaziseka ekubalekeni kwe-thermal, kwaye ubushushu bukhuphuka ngokukhawuleza ukuya kwi-135 ℃ xa inaliti ifakwe ebhetri. Ngaphezulu kwe-135 ℃, ukonyuka kwe-SHR kubangela ukubaleka kwebhetri, kwaye ubushushu bomphezulu bebhetri bunyuke ukuya kuma-400 ℃.

Kwabonwa into eyahlukileyo xa ibhetri entsha ihlawuliswa ngokuhlatywa inaliti. Ezinye iiseli ziye zaphulukana ngqo nolawulo lwe-thermal, ngelixa ezinye zingakhange ziphulukane nolawulo lobushushu xa ubushushu bomphezulu bugcinwe bungaphantsi kwe-125℃. Olunye lolawulo oluthe ngqo lwe-thermal yebhetri emva kwenaliti kwibhetri, ubushushu bomphezulu bufikelele kwi-700 ℃, nto leyo ebangela ukuba ifoyile ye-aluminium inyibilike, emva kwemizuzwana embalwa, ipali yanyibilika yaza yahlukana nebhetri, emva koko yavutha i-ejection. yegesi, kwaye ekugqibeleni yabangela ukuba iqokobhe lonke libe bomvu. Amaqela amabini eziganeko ezahlukeneyo anokuthiwa ukuba i-diaphragm iyanyibilika kwi-135℃. Xa iqondo lobushushu lingaphezulu kwe-135 ℃, i-diaphragm iyanyibilika kwaye isiphaluka esifutshane sangaphakathi sivele, sivelise ubushushu obuninzi kwaye ekugqibeleni bukhokhelele ekubalekeni kwe-thermal. Ukuqinisekisa oku, ibhetri ye-non-thermal ebalekayo yachithwa kwaye i-diaphragm yavavanywa yi-AFM. Iziphumo zabonisa ukuba imeko yokuqala yokunyibilika kwenwebu yabonakala kumacala omabini enwebu, kodwa ubume beporous lusabonakala kwicala elibi, kodwa hayi kwicala elihle.