Lithium mabhatiri achasangana nenzvimbo dzakasiyana panguva yekushandiswa kwavo. Munguva yechando, tembiricha kuchamhembe kweChina kazhinji iri pasi pe0 ℃ kana kunyange -10 ℃. Kana tembiricha yekuchaja uye yekuburitsa yebhatiri yadzikiswa pazasi 0 ℃, iyo yekuchaja uye yekuburitsa simba uye voltage yelithium bhatiri inoderera zvakanyanya. Izvi zvinodaro nekuti kufamba kwelithium ions mu electrolyte, SEI uye graphite zvimedu zvinodzikiswa pakudziya kwakaderera. Mamiriro ekunze akaomarara akadaro anozotungamira kune kunaya kwelithium simbi ine yakakwirira chaiyo nzvimbo.

Lithium kunaya ine yakakwira chaiyo nzvimbo ndechimwe chezvikonzero zvakakosha zvekutadza mabhatiri e lithium, uye zvakare idambudziko rakakosha rekuchengetedza bhatiri. Izvi zvinodaro nekuti ine nzvimbo yakakura kwazvo, lithium simbi inoshanda zvakanyanya uye inopfuta, nzvimbo yakakwira dendrite lithium imhepo shoma yakanyorova inogona kupiswa.

Nekuvandudzwa kwehuwandu hwebhatiri, huwandu uye chikamu chemusika chemotokari dzemagetsi, zvinodiwa zvekuchengetedza zvemotokari dzemagetsi zviri kuwedzera uye zvakanyanya kuomarara. Ndedzipi shanduko mukushanda kwemabhatiri emagetsi pakudziya kwakaderera? Ndeapi maitiro ekuchengetedza akakodzera kucherechedzwa?

1.18650 cryogenic cycle kuyedza uye bhatiri disassembly ongororo

Iyo 18650 bhatiri (2.2A, NCM523 / graphite system) yakateedzerwa paA yakaderera tembiricha ye0 ℃ pasi peAmwe kuchaja-kuburitsa michina. Iyo yekuchaja uye yekuburitsa mashandiro ndeiyi: CC-CV yekuchaja, chiyero chekuchaja i1C, kuchaja yakachekwa-kubvisa voltage ndeye 4.2V, kuchaja yekucheka-kubvisa ikozvino 0.05c, ipapo CC kuburitsa kusvika 2.75V. Sezvo bhatiri SOH ye70% -80% inowanzotsanangurwa semamiriro ekupedzisira (EOL) ebhatiri. Naizvozvo, mukuedza uku, bhatiri rinogumiswa kana iyo SOH yebhatiri iri 70%. Iko kutenderera kwebhatiri pasi pemamiriro ari pamusoro inoratidzwa muMufananidzo 1 (a). Li MAS NMR yekuongorora yakaitwa pamatanda uye diaphragms yemabhatiri anotenderera uye asina kutenderera, uye migumisiro yekuchinja kwemakemikari yakaratidzwa mumufananidzo 1 (b).

Mufananidzo 1. Cell cycle curve uye Li MAS NMR kuongorora

Iko kukwanisa kweiyo cryogenic cycle yakawedzera mumitambo mishomanana yekutanga, inoteverwa nekuderera kwakadzikama, uye SOH yakadonha pasi pe70% muzasi kwe50 cycles. Mushure mokuparadzanisa bhatiri, zvakaonekwa kuti pane chidimbu chesirivha-grey pamusoro peanode, iyo yaifungidzirwa kuva lithium metal yakaiswa pamusoro peinodedhi inotenderera. Li MAS NMR ongororo yakaitwa pamabhatiri emapoka maviri ekuenzanisa ekuenzanisa, uye mhedzisiro yacho yakasimbiswa zvakare muMufananidzo B.

Pane yakafara peak pa0ppm, zvichiratidza kuti lithium iripo muSEI panguva ino. Mushure mekutenderera, peak yechipiri inoonekwa pa255 PPM, inogona kuumbwa nekunaya kwerithium metal pamusoro peanode material. Kuti uwedzere kusimbisa kana lithium dendrites yakanyatso kuoneka, SEM morphology yakaonekwa, uye mhedzisiro yakaratidzwa mumufananidzo 2.

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Mufananidzo 2. SEM kuongorora migumisiro

Nokuenzanisa mifananidzo A neB, zvinogona kuonekwa kuti gobvu rezvinhu rakaumbwa mumufananidzo B, asi iyi dhizaini haina kunyatsovhara magirafu zvimedu. Iyo SEM magnification yakawedzera kukwidziridzwa uye tsono senge zvinhu zvakaonekwa muMufananidzo D, inogona kunge iri lithium ine yakakwirira chaiyo nzvimbo (inozivikanwawo se dendrite lithium). Uye zvakare, iyo lithium metal deposition inokura yakananga ku diaphragm, uye ukobvu hwayo hunogona kucherechedzwa nekuienzanisa nehupamhi hweiyo graphite layer.

Chimiro chekuiswa lithium chinoenderana nezvakawanda zvinhu. Zvakadai sekusagadzikana kwepasi, density yazvino, chinzvimbo chekuchaja, tembiricha, electrolyte additives, electrolyte kuumbwa, yakaiswa voltage uye zvichingodaro. Pakati pavo, kutenderera kwekushisa kwakadzika uye yakakwira ikozvino density ndiyo yakanyanya nyore kugadzira dense lithium simbi ine yakakwirira chaiyo nzvimbo.

2. Thermal stability analysis of battery electrode

TGA yakashandiswa kuongorora maelectrode ebhatiri asina kutenderedzwa uye akatenderedzwa, sezvinoratidzwa mumufananidzo 3.

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Mufananidzo 3. TGA kuongororwa kwemagetsi asina kunaka uye akanaka (A. Negative electrode B. Positive electrode)

Sezvinoonekwa kubva pamufananidzo uri pamusoro, iyo electrode isina kushandiswa ine matatu akakosha epamusoro paT≈260 ℃, 450 ℃ uye 725 ℃ zvakateerana, zvichiratidza kuti kuparara kwechisimba, evaporation kana sublimation reactions inoitika munzvimbo idzi. Zvisinei, kurasikirwa kukuru kwe electrode kwaiva pachena pa 33 ℃ uye 200 ℃. Kuparara kwekuita pakupisa kwakadzika kunokonzerwa nekuparara kweSEI membrane, hongu, zvakare kune chokuita nekugadzirwa kwe electrolyte nezvimwe zvinhu. Kunaya kwerithium simbi ine yakakwirira chaiyo nzvimbo inotungamira mukuumbwa kwenhamba huru yeSEI mafirimu pamusoro pelithium simbi, inovawo chikonzero chekurasikirwa kukuru kwemabhatiri pasi pekushisa kwakadzika kutenderera.

SEM haina kukwanisa kuona chero shanduko mune morphology yezvinhu zvecathode mushure mekuyedza cyclic, uye kuongororwa kweTGA kwakaratidza kuti pakanga paine kurasikirwa kwemhando yepamusoro apo tembiricha yaive pamusoro pe400 ℃. Uku kurasikirwa kukuru kunogona kukonzerwa nekuderedzwa kwe lithium mune cathode zvinhu. Sezvakaratidzwa muMufananidzo 3 (b), nekukwegura kwebheteri, zvinyorwa zveLi mu electrode yakanaka yeNCM zvishoma nezvishoma inoderera. Kurasikirwa kukuru kweSOH100% yakanaka electrode i4.2%, uye iyo yeSOH70% yakanaka electrode i5.9%. Mune izwi, huwandu hwekurasikirwa kwehuwandu hwezvose zvakanaka uye zvisina kunaka electrode inowedzera mushure mekutenderera kwe cryogenic.

3. Electrochemical aging analysis of electrolyte

Kufurira kwekushisa kwakadzika pabhatiri electrolyte kwakaongororwa neGC/MS. Electrolyte samples dzakatorwa kubva kumabhatiri asina zera uye achembera zvichiteerana, uye GC/MS mibairo yekuongorora yakaratidzwa muMufananidzo 4.

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Mufananidzo 4.GC/MS uye FD-MS mhinduro dzebvunzo

Iyo electrolyte yeiyo isiri-cryogenic cycle bhatiri ine DMC, EC, PC, uye FEC, PS, uye SN semisanganiswa yekuvandudza mashandiro ebhatiri. Huwandu hweDMC, EC nePC musero risingatenderere uye sero rinotenderera rakafanana, uye chinowedzera SN mu electrolyte mushure mekutenderera (chinotadzisa kuparara kweiyo positive electrode electrolytic liquid liquid iri pasi pe high voltage) inoderedzwa. , saka chikonzero ndechekuti iyo yakanaka electrode inowandisa zvishoma pasi peyakaderera tembiricha kutenderera. BS neFEC iSEI firimu inogadzira zvinowedzera, zvinokurudzira kuumbwa kwemafirimu akagadzikana eSEI. Mukuwedzera, FEC inogona kuvandudza kutenderera kugadzikana uye Coulomb kushanda zvakanaka kwemabhatiri. PS inogona kuwedzera kugadzikana kwekupisa kweanode SEI. Sezvingaonekwa kubva pamufananidzo, huwandu hwePS hahuderedze nekuchembera kwebhatiri. Paiva nekuderera kwakanyanya kwehuwandu hweFEC, uye apo SOH yaiva 70%, FEC yaisagona kuonekwa. Kunyangarika kweFEC kunokonzerwa nekuenderera mberi kwekuvakwa kweSEI, uye kudzokororwa kweSEI kunokonzerwa nekunaya kunoramba kuripo kweLi pane cathode graphite pamusoro.

Chigadzirwa chikuru che electrolyte mushure mekutenderera kwebhatiri iDMDOHC, iyo synthesis inoenderana nekuumbwa kweSEI. Naizvozvo, nhamba huru yeDMDOHC muFIG. 4A inoreva kuumbwa kwenzvimbo huru dzeSEI.

4. Thermal kugadzikana kuongororwa kwemabhatiri e-non-cryogenic cycle

ARC (Accelerated calorimeter) bvunzo dzakaitwa pane isiri-cryogenic cycle uye cryogenic cycle mabhatiri pasi pe quasi-adiabatic mamiriro uye HWS modhi. Arc-hws mhedzisiro yakaratidza kuti exothermic reaction yakakonzerwa nemukati mebhatiri, yakazvimirira yekunze ambient tembiricha. Kuita mukati mebhatiri kunogona kukamurwa kuita nhanho nhatu, sezvakaratidzwa muTable 1.

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Kupisa kwakati kunoitika panguva yekupisa kwediaphragm uye kuputika kwebhatiri, asi diaphragm thermalization haina basa kune iyo SHR yese. Iko kutanga kwe exothermic reaction kunobva pakuora kweSEI, inoteverwa nekupisa kwekupisa kukonzeresa kubviswa kwelithium ion, kusvika kwemaerekitironi kunzvimbo yegraphite, uye kuderedzwa kwemaerekitironi kuti agadzirise zvakare SEI membrane. Thermal kugadzikana bvunzo mhinduro inoratidzwa muFigure 5.

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Mufananidzo 5. Arc-hws zvawanikwa (a) 0%SOC; (b) 50 muzana yeSOC; (c) 100 muzana yeSOC; Mitsetse yakatsetseka ndiyo yekutanga exothermic reaction tembiricha, tembiricha yekutanga inomhanya yekupisa uye tembiricha inomhanya yekupisa.

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Mufananidzo 6. Arc-hws dudziro yemhedzisiro a. Kupisa kwekupisa, B.ID kutanga, C. Kupisa kwekutanga kwekupisa kwekupisa d. Yekutanga tembiricha ye exothermic reaction

Iyo yekutanga exothermic reaction (OER) yebhatiri isina cryogenic cycle inotanga kutenderedza 90 ℃ uye inowedzera mutsetse kusvika 125 ℃, nekudzikira kweSOC, zvichiratidza kuti OER inotsamira zvakanyanya kune mamiriro elithium ion muanode. Kune bhatiri riri mukuburitsa, iyo yepamusoro-soro SHR (yega-yekudziya mwero) mukuora kwekuita inogadzirwa panosvika 160 ℃, uye iyo SHR inodzikira pakupisa kwakanyanya, saka kushandiswa kweiyo intercalated lithium ion kunotemerwa paiyo negative electrode. .

Chero bedzi paine yakakwana lithium ions mune yakashata electrode, inovimbiswa kuti iyo yakakuvadzwa SEI inogona kuvakwa patsva. Kuora kwekupisa kwecathode zvinhu kunoburitsa okisijeni, iyo inozoisa oxidize ne electrolyte, inozotungamira kune maitiro ekupisa kwekutiza kwebhatiri. Pasi pepamusoro peSOC, iyo cathode zvinhu zviri mune yakanyanya delithium mamiriro, uye chimiro cheiyo cathode zvinhu zvakare haina kugadzikana. Chii chinoitika ndechekuti kugadzikana kwekupisa kwesero kunoderera, huwandu hweokisijeni inoburitswa hunowedzera, uye kuita pakati peiyo yakanaka electrode uye electrolyte inotora pane yakanyanya tembiricha.

4. Kusunungurwa kwesimba panguva yekugadzirwa kwegesi

Kuburikidza nekuongororwa kweiyo post-cycle bhatiri, zvinogona kuoneka kuti SHR inotanga kukura mumutsara wakatwasuka wakatenderedza 32 ℃. Kuburitswa kwesimba mukugadzirwa kwegasi kunonyanya kukonzerwa nekuora kwekuita, iyo inowanzofungidzirwa kuve kuparara kwemafuta e electrolyte.

Lithium simbi ine yakakwirira chaiyo nzvimbo inokwira pamusoro peiyo anode zvinhu, iyo inogona kuratidzwa neinotevera equation.

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Mukushambadzira, Cp ndeyekupisa kwakaringana, uye △T inomiririra huwandu hwekuzvipisa tembiricha yekukwira kwebhatiri kunokonzerwa nekuora maitiro mukuyedza kweARC.

Iwo chaiwo ekupisa masimba emaseru asina kutenderedzwa pakati pe30 ℃ ne120 ℃ akaedzwa mukuyedza kweARC. Iyo exothermic reaction inoitika pa125 ℃, uye bhatiri riri mu discharge state, uye hapana imwe exothermic reaction inoikanganisa. Muchiyedzo ichi, CP ine hukama hwemutsara netembiricha, sezvakaratidzwa mune inotevera equation.

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Huwandu hwesimba hwakaburitswa mukuita kwese hunogona kuwanikwa nekubatanidza iyo chaiyo yekupisa huwandu, inova 3.3Kj pasero kuchembera pakudziya kwakaderera. Kuwanda kwesimba rakabudiswa panguva yekupisa kwemhepo haigoni kuverengwa.

5. Acupuncture kuedza

Kuti usimbise pesvedzero yekuchembera kwebhatiri pane bhatiri pfupi redunhu kuyedza, kuyedza tsono kwakaitwa. Migumisiro yekuedza inoratidzwa mumufananidzo uri pasi apa:

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Kana iri mhedzisiro yeacupuncture, A ndiyo tembiricha yebhatiri panguva yeacupuncture process, uye B ndiyo yakanyanya tembiricha inogona kuwanikwa.

Zvinogona kuonekwa kubva pamufananidzo kuti pane musiyano mudiki we10-20 ℃ pakati pebhatiri rekuchembera mushure mekubuda uye bhatiri nyowani (SOC 0%) neinoda bvunzo. Kune sero zera, tembiricha yakakwana inosvika T≈35℃ pasi peadiabatic mamiriro, anowirirana neSHR≈0.04K/min.

Bhatiri risina kushandiswa rinosvika pakupisa kwepamusoro kwe120 ℃ mushure memasekondi makumi matatu apo iyo SOC iri 30%. Kupisa kwejoule kwakaburitswa hakuna kukwana kusvika kune tembiricha iyi, uye iyo SHR inodarika huwandu hwekupisa kwekupisa. Kana SOC iri 50%, bhatiri rekuchembera rine kumwe kunonoka kukonzeresa pakupisa kwemhepo, uye tembiricha inokwira zvakanyanya kusvika 50 ℃ kana tsono yaiswa mubhatiri. Pamusoro pe135 ℃, kuwedzera kweSHR kunokonzera kutiza kwebhatiri, uye tembiricha yebhatiri inokwira kusvika 135 ℃.

Chiitiko chakasiyana chakaonekwa apo bhatiri idzva rakachajwa nebayo retsono. Mamwe maseru akarasikirwa nekudzora kupisa, nepo mamwe haana kurasikirwa nekudzora kupisa apo tembiricha yepasi yaichengetwa iri pasi pe125 ℃. Imwe yekudzora yakananga yekupisa kwebhatiri mushure metsono mubhatiri, tembiricha yepasi yakasvika 700 ℃, zvichiita kuti aluminium foil inyauke, mushure memasekondi mashoma, danda rakanyungudutswa ndokuparadzaniswa nebhatiri, ndokuzobatidza ejection. yegasi, uye pakupedzisira yakakonzera goko rose dzvuku. Iwo mapoka maviri ezviitiko zvakasiyana anogona kufungidzirwa kuti diaphragm inonyunguduka pa135 ℃. Kana tembiricha yakakwira kupfuura 135 ℃, diaphragm inonyunguduka uye yemukati pfupi seketi inooneka, ichiunza kupisa kwakawanda uye pakupedzisira ichitungamira mukupisa kwekupisa. Kuti uone izvi, bhatiri rekutiza risiri rinopisa rakabviswa uye diaphragm yakaedzwa neAFM. Mhedzisiro yacho yakaratidza kuti mamiriro ekutanga ekunyunguduka kwe membrane akaonekwa pamativi ese e membrane, asi porous chimiro chichiri kuoneka kudivi rakashata, asi kwete kudivi rakanaka.