Sei iyo lithium iron phosphate bhatiri ichitadza?

Kunzwisisa chikonzero kana nzira yekutadza kwe lithium iron phosphate mabhatiri kwakakosha mukuvandudza mashandiro ebhatiri uye kugadzirwa kwayo kwakakura uye kushandiswa. Ichi chinyorwa chinokurukura mhedzisiro yetsvina, nzira dzekugadzira, mamiriro ekuchengetera, kudzokorodza, kuwandisa, uye kuburitsa zvakanyanya pakutadza kwebhatiri.

1. Kukundikana mubasa rekugadzira

Mukuita kwekugadzira, vashandi, zvishandiso, zvigadzirwa, nzira, uye nharaunda ndizvo zvinhu zvikuru zvinokanganisa kunaka kwechigadzirwa. Mukugadzirwa kweLiFePO4 mabhatiri emagetsi, vashandi uye zvishandiso ndezvechikamu chekutungamira, saka isu tinonyanya kukurukura matatu ekupedzisira emhedzisiro chinhu.

Izvo zvisina kuchena mune inoshanda electrode zvinhu zvinokonzeresa kutadza kwebhatiri.

Munguva yekugadzirwa kweLiFePO4, pachava nenhamba shoma yetsvina yakadai seFe2O3 neFe. Izvi zvinosvibisa zvichadzikiswa pamusoro peiyo negative electrode uye inogona kuboora diaphragm uye kukonzera mukati pfupi dunhu. Kana LiFePO4 yaratidzwa kumhepo kwenguva yakareba, mwando unoshatisa bhatiri. Muchikamu chekutanga chekukwegura, amorphous iron phosphate inoumbwa pamusoro pezvinhu. Kuumbwa kwayo kwenzvimbo uye chimiro chakafanana neLiFePO4 (OH); nekuiswa kweOH, LiFePO4 inoramba ichipedzwa, Inoratidzwa sekuwedzera kwehuwandu; gare gare yakadzokororwa zvishoma nezvishoma kuita LiFePO4 (OH). Iyo Li3PO4 tsvina muLiFePO4 ndeye electrochemically inert. Iyo yakakwirira yehutsvina yemukati yegraphite anode, iyo yakakura iyo isingachinjiki yekurasikirwa kwesimba.

Kukundikana kwebhatiri kunokonzerwa nenzira yekugadzira

Kurasikirwa kusingadzoreki kweanoshanda lithium ion kunotanga kuratidzwa muiyo lithium ion inodyiwa ichigadzira iyo yakasimba electrolyte interfacial membrane. Zvidzidzo zvakawana kuti kuwedzera tembiricha yekugadzira kunokonzeresa kurasikirwa kusingadzoreki kwe lithium ions. Kana tembiricha yekugadzira yawedzerwa, chikamu chezvikamu zvemukati muSEI firimu chichawedzera. Iyo gasi yakaburitswa panguva yekushandura kubva kune organic chikamu ROCO2Li kune inorganic chikamu Li2CO3 ichakonzera kukanganisa kwakawanda muSEI firimu. Nhamba huru yelithium ions inogadziriswa nezvikanganiso izvi ichaiswa mukati meiyo negative graphite electrode.

Munguva yekuumbwa, kuumbwa uye kukora kwefirimu yeSEI yakaumbwa nekuchaja kwepasi-ikozvino inofanana asi inotora nguva; Kuchaja kwepamusoro-ikozvino kunokonzeresa maitiro eparutivi kuti aitike, zvichikonzera kuwedzera kusingachinjike kurasikirwa kwelithium-ion uye iyo yakaipa electrode interface impedance ichawedzerawo, asi inochengetedza nguva. Nguva; Mazuva ano, magadzirirwo emhando yediki yazvino inogara iripo-hombe ikozvino inogara iripo uye inogara voltage inoshandiswa kakawanda kuitira kuti itore zvakanakira zvese mukufunga.

Kukundikana kwebhatiri kunokonzerwa nehunyoro munzvimbo yekugadzira

Mukugadzirwa chaiko, bhatiri rinosangana nemhepo zvisingadzivisiki nekuti zvinhu zvakanaka uye zvisina kunaka zvakanyanya mamicron kana nano-sized particles, uye mamorekuru anonyungudutsa ari muelectrolyte ane mahombe eelectronegative carbonyl mapoka uye metastable carbon-carbon double bonds. Zvose zviri nyore kutora unyoro mumhepo.

Mamorekuru emvura anoita nerithium munyu (kunyanya LiPF6) iri muelectrolyte, iyo inoora nekudya electrolyte (inoora kuita PF5) uye inoburitsa acidic substance HF. Zvese zviri zviviri PF5 neHF zvichaparadza iyo SEI firimu, uye HF ichasimudzirawo kukora kweLiFePO4 inoshanda zvinhu. Mamorekuru emvura achaitawo delithiate iyo lithium-intercalated graphite negative electrode, ichigadzira lithium hydroxide pazasi peSEI firimu. Mukuwedzera, O2 yakanyungudutswa mu electrolyte ichaitawo kukurumidza kukwegura kwe LiFePO4 mabhatiri.

Muchigadziro chekugadzira, kunze kwekugadzirwa kwekugadzira kunobata kushanda kwebheteri, zvinhu zvikuru zvinokonzera kukanganisa kweLiFePO4 simba bhatiri zvinosanganisira kusvibiswa kwezvinhu zvakasvibiswa (kusanganisira mvura) uye nzira yekugadzira, saka kuchena kwe zvinhu, kutonga kwehunyoro hwezvakatipoteredza, nzira yekugadzira, nezvimwe zvinhu zvakakosha.

2. Kukundikana musherufu

Munguva yehupenyu hwebasa rebhatiri remagetsi, nguva zhinji yaro iri musherufu. Kazhinji, mushure menguva yakareba yekuchengetera, kushanda kwebhatiri kunoderera, kazhinji kunoratidza kuwedzera kwekupikisa kwemukati, kuderera kwemagetsi, uye kuderera kwekubuda simba. Zvinhu zvakawanda zvinokonzeresa kuderera kwekuita kwebhatiri, iyo tembiricha, mamiriro ekuchaja, uye nguva ndizvo zvinonyanya kuoneka zvinofurira zvinhu.

Kassem et al. akaongorora kuchembera kweLiFePO4 mabhatiri emagetsi pasi pemamiriro akasiyana ekuchengetedza. Vaitenda kuti nzira yekuchembera ndiyo inonyanya kuita mativi emagetsi akanaka uye asina kunaka. Iyo electrolyte (inofananidzwa nerutivi rwekuita kwe electrode yakanaka, rutivi rwekuita kweiyo negative graphite electrode inorema, kunyanya inokonzerwa ne solvent. Kuparara, kukura kwefirimu yeSEI) inoshandisa ion lithium ions. Panguva imwecheteyo, iyo impedance yakazara yebhatiri inowedzera, kurasikirwa kweiyo inoshanda lithium ions kunotungamirira kukwegura kwebheteri kana yasara. Kurasikirwa kwesimba kweLiFePO4 mabhatiri emagetsi kunowedzera nekukwira kwekushisa kwekuchengetedza. Kusiyana neizvi, sezvo mamiriro ekuchengetedza ekubhadhara anowedzera, kurasikirwa kwesimba kunowedzera kudiki.

Grolleau et al. yakasvikawo pamhedziso imwechete: tembiricha yekuchengetera ine zvakanyanya kukosha pakuchembera kweLiFePO4 mabhatiri emagetsi, inoteverwa nenzvimbo yekuchengetedza yekubhadharisa, uye muenzaniso wakapusa unotsanangurwa. Inogona kufanotaura kurasikirwa kwesimba reLiFePO4 simba bhatiri zvichienderana nezvinhu zvine chekuita nenguva yekuchengetedza (tembiricha uye mamiriro ekubhadhara). Mune imwe nzvimbo yeSOC, sezvo nguva yesherufu inowedzera, lithiamu iri mugirafu ichapararira kusvika kumucheto, ichiita musanganiswa wakaoma ne electrolyte uye ma electrons, zvichiita kuti kuwedzera kwechikamu cheti irreversible lithium ions, kuwedzera kweSEI, uye conductivity. Kuwedzera kwe impedance kunokonzerwa nekudzikira (inorganic components kuwedzera, uye vamwe vane mukana wekunyungudika zvakare) uye kudzikiswa kwekuita kwe electrode surface pamwe chete kunokonzera kuchembera kwebhatiri.

Pasinei nemamiriro ekuchaja kana mamiriro ekuburitsa, iyo yekusiyanisa scanning calorimetry haina kuwana chero maitiro pakati peLiFePO4 uye akasiyana electrolytes (iyo electrolyte iri LiBF4, LiAsF6, kana LiPF6) mutembiricha kubva mukamuri tembiricha kusvika 85 ° C. Nekudaro, kana LiFePO4 yakanyudzwa muelectrolyte yeLiPF6 kwenguva yakareba, icharamba ichiratidzira chaiyo reactivity. Nekuti maitiro ekugadzira iyo interface akareba, hapasati pasati pave firimu rekufambisa pamusoro peLiFePO4 kudzivirira kumwe kuita ne electrolyte mushure mekunyudza kwemwedzi mumwe.

Mumamiriro ekuchengetedza masherufu, mamiriro ezvinhu asina kunaka ekuchengetedza (kupisa kwepamusoro uye kukwira kwepamusoro) kuchawedzera dhigirii yekuzvibudisa yega yeLiFePO4 simba bhatiri, zvichiita kuti bhatiri ichembera zvive pachena.

3. Kutadza kugadzirazve

Mabhatiri anowanzo buritsa kupisa panguva yekushandiswa, saka pesvedzero yetembiricha yakakosha. Pamusoro pezvo, mamiriro emumugwagwa, kushandiswa, uye ambient tembiricha zvese zvichave nemhedzisiro dzakasiyana.

Kurasikirwa kweiyo inoshanda lithium ion kunowanzo kukonzeresa kurasikirwa kwesimba reLiFePO4 simba mabhatiri panguva yebhasikoro. Dubarry et al. yakaratidza kuti kuchembera kweLiFePO4 mabhatiri emagetsi panguva yebhasikoro kunonyanya kukonzerwa nekukura kwakaoma kunopedza kushanda lithium-ion SEI firimu. Muchiitiko ichi, kurasikirwa kweiyo inoshanda lithium ions kunoderedza zvakananga chiyero chekuchengetedza kwehuwandu hwebheteri; kuenderera mberi kwekukura kweSEI firimu, kune rumwe rutivi, kunokonzera kuwedzera kwepolarization kuramba kwebhatiri. Panguva imwecheteyo, ukobvu hweSEI firimu hwakanyanya kukora, uye electrochemical performance yegraphite anode. Ichaita kuti chiitwa chisashande.

Munguva yekukwira-tembiricha bhasikoro, Fe2+ muLiFePO4 ichanyungudika kune imwe nhanho. Kunyange zvazvo huwandu hweFe2 + yakanyungudutswa husina chinhu chakakosha pakukwanisa kwe electrode yakanaka, kupera kweFe2 + uye kunaya kweFe pamhepo yakaipa ye graphite electrode ichaita basa rinokurudzira mukukura kwefirimu yeSEI. . Tan quantitatively akaongorora kupi uye kupi iyo inoshanda lithium ion yakarasika uye yakawana kuti yakawanda yekurasikirwa kweiyo inoshanda lithium ion yakaitika pamusoro peiyo negative graphite electrode, kunyanya panguva yekudziya kwepamusoro-kutenderera, ndiko kuti, iyo yakanyanya-temperature cycle simba kurasikirwa. inokurumidza, uye muchidimbu iyo SEI firimu Pane nzira nhatu dzakasiyana dzekukuvadza nekugadzirisa:

1. Maerekitironi ari mugraphite anode anopfuura nepakati peSEI firimu kuderedza lithium ions.
2. Kuparara uye kuvandudzwa kwezvimwe zvikamu zveSEI firimu.
3. Nekuda kwekushanduka kwevhoriyamu yegraphite anode, Iyo SEI membrane yakakonzerwa nekutsemuka.

Pamusoro pekurasikirwa kweiyo inoshanda lithium ion, zvese zvakanaka uye zvisina kunaka zvinhu zvichadzikira panguva yekudzokorodza. Kuitika kwekutsemuka muLiFePO4 electrode panguva yekudzokorodza kuchaita kuti electrode polarization iwedzere uye conductivity pakati peiyo inoshanda zvinhu uye conductive agent kana iyezvino muunganidzi kuderera. Nagpure akashandisa Scanning Extended Resistance Microscopy (SSRM) kuti semi-quantitatively kudzidza shanduko yeLiFePO4 mushure mekuchembera uye yakaona kuti kukoromoka kweLiFePO4 nanoparticles uye madhipoziti epamusoro anogadzirwa neakananga makemikari maitiro pamwe chete akakonzera kuwedzera kweiyo impedance yeLiFePO4 cathodes. Mukuwedzera, kuderedzwa kwekushanda kwepamusoro uye kuputika kwe graphite electrodes kunokonzerwa nekurasikirwa kwezvinhu zvinoshanda zve graphite zvinoonekwawo sechikonzero chekukwegura kwebheteri. Kusagadzikana kwegraphite anode kuchaita kuti kusagadzikana kweiyo SEI firimu uye kukurudzira kushandiswa kweiyo inoshanda lithium ions.

Kubudiswa kwepamusoro-soro kwebheteri kunogona kupa simba rinokosha remotokari yemagetsi; ndiko kuti, zviri nani chiyero chekushanda kwebhatiri remagetsi, zviri nani kukurumidza kuita kwemotokari yemagetsi. Mhedzisiro yekutsvagisa yaKim et al. yakaratidza kuti nzira yekukwegura yeLiFePO4 yakanaka electrode uye graphite negative electrode yakasiyana: nekuwedzera kwehuwandu hwekubuda, kurasikirwa kwekwanisi ye electrode yakanaka kunowedzera kupfuura iyo ye electrode yakaipa. Kurasikirwa kwesimba rebhatiri panguva yakaderera-chiyero chebhasikoro kunonyanya kukonzerwa nekushandiswa kweiyo inoshanda lithium ions mune iyo yakaipa electrode. Kusiyana neizvi, kurasikirwa kwesimba kwebhatiri panguva yebhasikoro yepamusoro kunokonzerwa nekuwedzera kwekudzivirira kwe electrode yakanaka.

Kunyangwe kudzika kwekubuda kwebhatiri remagetsi mukushandiswa hakuzokanganisa kurasikirwa kwesimba, kunokanganisa kurasikirwa kwayo kwesimba: kukurumidza kwekurasikirwa kwesimba kunowedzera nekuwedzera kwekudzika kwekubuda. Izvi zvinokonzerwa nekukwira kweimpedance yeSEI firimu uye kuwedzera kweimpedance yebhatiri rose. Yakabatana zvakananga. Kunyangwe zvichienderana nekurasikirwa kweiyo inoshanda lithium ion, iyo yepamusoro muganhu weiyo yekuchaja voltage haina mhedzisiro inoratidzika pakutadza kwebhatiri, yakadzikira kana yakanyanya kukwirisa kumusoro kweiyo voltage yekuchaja ichawedzera iyo interface impedance yeLiFePO4 electrode: yakaderera kumusoro. limit voltage haishande zvakanaka. Iyo passivation firimu inoumbwa pasi, uye yakanyanya-yakakwirira-yepamusoro voltage inogumira ichakonzera iyo oxidative Kuparara kwe electrolyte. Ichagadzira chigadzirwa chine conductivity yakaderera pamusoro peLiFePO4 electrode.

Iyo yekuburitsa simba reLiFePO4 simba bhatiri inodonha nekukurumidza kana tembiricha yadzikira, kunyanya nekuda kwekuderedzwa kweion conductivity uye kuwedzera kweiyo interface impedance. Li akadzidza LiFePO4 cathode uye graphite anode zvakasiyana uye akawana kuti zvinhu zvikuru zvinodzora zvinoderedza kuderera kwekushisa kweanode uye anode zvakasiyana. Kuderera kweiyo ionic conductivity yeLiFePO4 cathode ndiyo yakanyanya, uye kuwedzera kweiyo interface impedance yegraphite anode ndicho chikonzero chikuru.

Munguva yekushandiswa, kuderedzwa kweLiFePO4 electrode uye graphite anode uye kuenderera mberi kweSEI firimu kuchaita kuti bhatiri rikundike kune akasiyana madhigirii. Mukuwedzera, pamusoro pezvinhu zvisingadzoreki zvakadai semamiriro emugwagwa uye tembiricha yepakati, kushandiswa kwebhatiri nguva dzose kwakakosha zvakare, kusanganisira yakafanira yekuchaja voltage, kudzika kwakakodzera kwekubuda, nezvimwe.

4. kukundikana panguva yekubhadhara uye kubvisa

Bhatiri rinowanzo wedzera kuchajwa panguva yekushandiswa. Kune kushoma-kubuda-kudarika. Kupisa kunoburitswa panguva yekuchaja kana kubuda zvakanyanya kunogona kuungana mukati mebhatiri, zvichiwedzera kuwedzera tembiricha yebhatiri. Inokanganisa hupenyu hwesevhisi yebhatiri uye inosimudza mukana wemoto kana kuputika kwedutu. Kunyangwe pasi penguva dzose yekuchaja uye kuburitsa mamiriro, sezvo huwandu hwekutenderera hunowedzera, kusawirirana kwesimba kwesero rimwe chete mubhatiri system kuchawedzera. Bhatiri rine simba rakaderera rinozopinda maitiro ekuchajisa uye kunyanya-kuburitsa.

Kunyange zvazvo LiFePO4 ine yakanyanya kugadzikana yekupisa kana ichienzaniswa nezvimwe zvinhu zvakanaka zve electrode pasi pemamiriro akasiyana ekuchaja, kuwandisa kunogona kukonzera njodzi dzisina kuchengeteka mukushandisa LiFePO4 mabhatiri emagetsi. Munyika yakawandisa, chinonyungudutsa chiri muorganic electrolyte chinowanzoita oxidative Decomposition. Pakati pezvinowanzo shandiswa organic solvents, ethylene carbonate (EC) inozonyanya kuita oxidative Decomposition pamusoro peiyo yakanaka electrode. Sezvo simba rekuisa lithium (rinopesana ne lithium rinogona) regetsi yegirafu electrode isina kudzika, kunaya kwe lithium kunowanzoitika mugerodhi isina kunaka yegraphite.

Chimwe chezvikonzero chikuru chekutadza kwebhatiri pasi pemamiriro akawandisa ndeyemukati pfupi dunhu rinokonzerwa ne lithium crystal matavi anobaya diaphragm. Lu et al. akaongorora kukundikana kwemaitiro e lithium plating pane graphite inopesana ne electrode pamusoro inokonzerwa nekuwedzerwa. Mhedzisiro inoratidza kuti chimiro chese cheiyo negative graphite electrode haina kushanduka, asi kune lithium crystal matavi uye pamusoro firimu. Kuita kwe lithium uye electrolyte kunoita kuti firimu repamusoro rirambe richiwedzera, iro rinoshandisa lithium rinoshanda uye rinokonzera kuti lithium ipararire kuita graphite. Iyo yakaipa electrode inova yakanyanya kuoma, iyo inozowedzera kukurudzira lithium deposition pamusoro peiyo yakaipa electrode, zvichikonzera kuwedzera kuderera kwesimba uye coulombic kunyatsoshanda.

Mukuwedzera, tsvina yesimbi (kunyanya Fe) inowanzoonekwa sechimwe chezvikonzero zvikuru zvekukundikana kwebhatiri. Xu et al. yakarongeka yakadzidza nzira yekukundikana kweLiFePO4 mabhatiri emagetsi pasi pemamiriro ekuwedzera. Mhedzisiro yacho inoratidza kuti iyo redox yeFe panguva yekuwedzeredza / kuburitsa kutenderera kunogoneka, uye maitiro ekuita anopihwa. Kana overcharge ikaitika, Fe inotanga oxidized kuFe2+, Fe2+ inowedzera kuipa kusvika kuFe3+, uyezve Fe2+ neFe3+ zvinobviswa kubva kune electrode yakanaka. Rimwe divi rinopararira kune rimwe divi rakashata re electrode, Fe3 + inopedzisira yaderedzwa kusvika Fe2 +, uye Fe2 + inowedzera kuderedzwa kuita Fe; apo overcharge / discharge cycles, Fe crystal matavi achatanga pamagetsi akanaka uye asina kunaka panguva imwe chete, achibaya muparadzi kuti agadzire mabhiriji eFe, zvichiita kuti microbhateri Short circuit, chiitiko chinooneka chinofambidzana nebhatiri micro short circuit ndiyo inopfuurira. kuwedzera tembiricha mushure mekuwandisa.

Munguva yekuwedzera, kukwanisa kwe electrode yakaipa ichakwira nokukurumidza. Iyo inogona kuwedzera ichaparadza iyo SEI firimu pamusoro peiyo yakaipa electrode (chikamu chakapfuma mumakemikari emusero muSEI firimu anowanzo kuve oxidized), izvo zvichakonzera kuwedzera Kuora kweiyo electrolyte, zvichikonzera kurasikirwa kwekugona. Zvinotonyanya kukosha, iyo yakaipa ikozvino muunganidzi Cu foil ichave oxidized. Mune SEI firimu reiyo negative electrode, Yang et al. yakaona Cu2O, iyo oxidation chigadzirwa cheCu foil, iyo inogona kuwedzera mukati mebhatiri kuramba uye kukonzera kurasikirwa kwesimba redutu.

Iye et al. akadzidza pamusoro-discharge maitiro eLiFePO4 simba mabhatiri mune zvakadzama. Mhedzisiro yacho yakaratidza kuti iyo yakaipa ikozvino muunganidzi Cu foil inogona kuve oxidized kuCu + panguva yakawandisa-kubuda, uye Cu + inowedzerwa oxidized kuCu2 +, mushure mezvo ivo vanopararira kune yakanaka electrode. Kuita kwekudzikisa kunogona kuitika pane yakanaka electrode. Nenzira iyi, inoumba matavi ekristaro padivi rakanaka re electrode, kubaya muparadzi uye kukonzera micro short circuit mukati mebhatiri. Zvakare, nekuda kwekuwandisa-kuburitsa, tembiricha yebhatiri icharamba ichikwira.

Overcharge yeLiFePO4 simba bhatiri inogona kukonzera oxidative electrolyte decomposition, lithium evolution, uye kuumbwa kweFe crystal mapazi; kunyanya-kubuda kunogona kukonzera SEI kukuvadzwa, zvichikonzera kuderera kwehuwandu, Cu foil oxidation, uye kunyange kutaridzika Cu crystal mapazi.

5. kumwe kukundikana

Nekuda kweiyo inherent low conductivity yeLiFePO4, iyo morphology uye saizi yezvinhu pachayo uye mhedzisiro ye conductive agents uye mabhaidhi zvinoratidzwa zviri nyore. Gaberscek et al. yakakurukura zvinhu zviviri zvinopesana zvehukuru uye carbon coating uye yakaona kuti electrode impedance yeLiFePO4 inongobatana chete nehuwandu hwehuwandu hwehuwandu. Izvo zvinokonzerwa ne-anti-site defects muLiFePO4 (Fe inobata Li nzvimbo) ichava nemigumisiro yakananga pakushanda kwebhatiri: nokuti kutapurirwa kwe lithium ions mukati meLiFePO4 kune imwe-dimensional, kukanganisa uku kuchadzivisa kutaurirana kwe lithium ions; nekuda kwekuiswa kwepamusoro valence states Nekuda kwekuwedzera kwe electrostatic repulsion, kukanganisa uku kunogona kukonzera kusagadzikana kweiyo LiFePO4 chimiro.

Zvikamu zvakakura zveLiFePO4 hazvigone kufara zvachose pakupera kwekuchaja; iyo nano-yakaumbwa LiFePO4 inogona kuderedza inversion defects, asi iyo yakakwirira pamusoro pesimba inokonzeresa kuzviburitsa. PVDF ndiro rinonyanya kushandiswa bhainda pari zvino, rine zvarakaipira sekuita patembiricha yakakwira, kunyungudika mumagetsi asiri emvura, uye kusakwanisa kuchinjika. Iyo ine chekuita nekurasikirwa kwekugona uye kutenderera hupenyu hweLiFePO4. Uye zvakare, iye zvino muunganidzi, diaphragm, electrolyte kuumbwa, maitiro ekugadzira, zvinhu zvevanhu, kuzunguzika kwekunze, kuvhunduka, nezvimwewo, zvinokanganisa mashandiro ebhatiri kune akasiyana madhigirii.

Chirevo: Miao Meng et al. "Kufambira mberi kwekutsvakurudza pamusoro pekukundikana kweLithium Iron Phosphate Power Batteries."