Chii chinonzi Battery Capacity Degradation Mechanism?
Kuchinja Mukurongeka Kwezvinhu
Izvo zvino zvakanyanya kushandiswa zvakanyanya zvecathode zvinhu zvinonyanya zvinosanganisira hexagonal layered chimiro cheLiMO2 (apo M=Co, Ni, Mn), iyo spinel chimiro cheLiMn2O4, uye olivine chimiro cheLiFePO4. Pasinei nechimiro, apo lithium ions inoparadzana kubva kune cathode, kuchengetedza mamiriro emagetsi mune zvinyorwa, chinhu chesimbi chinenge chisina kuvharwa kune imwe nzvimbo yakakwirira yevalence, iyo inoperekedzwa nechikamu chekuchinja. Kuchinja kwechikamu kunowanzoita kuti pave nekuchinja kwechikamu, kuitira kuti lithium ions irambe ichipindirana uye ichiparadzanisa muzvinhu, kuchinja kwechikamu kunoenderera mberi, uye nekufamba kwenguva, kuchaita kuti kuve nekutyisidzira kugadzikana kwekristini. Kuenzaniswa neanode, iyo isina kuenzana inodzoserwa simba inokonzerwa nechikamu chekuchinja uye shanduko mune yakawanda chimiro cheiyo cathode zvinhu zvine mhedzisiro yakakosha pahupenyu hwebhatiri. Graphite ine layered structure. Kana iine zvidimbu zvakati wandei, lithium ions inopindirana mumainterlayers panguva yekuchaja bhatiri uye inobatanidza maerekitironi anotakurwa kubva kudunhu rekunze kuumba lithiated graphite, uye nzvimbo yepakati inowedzera panguva ino; panguva yekubuda, lithium ions inosiya ma graphite interlayers uye inosunungura maerekitironi kudunhu rekunze, ichiita deintercalation uye oxidation reaction, uye interlayer spacing inoderera panguva ino.
Kuparara kweActive Material
Kunyunguduka kwekathodhi (cathode material) zvinoreva maitirwo ekuti chinhu chinoshanda chinodzikira zvishoma nezvishoma nokuda kwekuora mu electrolyte. Kunyungudika kwezvinhu zvecathode pakupisa kwakanyanya ndicho chimwe chezvikonzero zvekuora kwebhatiri, kunyanya kuve nekukanganisa kukuru pakuita kutenderera uye mashandiro ekuchengetedza mabhatiri pakupisa kwakanyanya. Kuparara kwesimbi yekuchinja pasi pemamwe mamiriro idambudziko riripo mune zvese LiMO2 cathode zvinhu. Zvikonzero zvikuru nei kuparara kwezvinhu zvinoshanda kunotungamirira kukuora kwekushanda kwebheteri ndezvi: $\\textcircled{1}$ Kuparara kwezvinhu zvesimbi zvinotungamirira zvakananga kuderedzwa kwezvinhu zvinoshanda, zvichiita kuti bhatiri iparadze simba; $\\textcircled{2}$ Kuparara kwezvinhu zvecathode kunokonzera kuparara kwechimiro chechimiro uye kuumbwa kwemakemikari asingashandisi zvinhu pamusoro pezvikamu, izvo zvinodzivisa kutakura kwe lithium ions mu electrode material; $\\textcircled{3}$ Ioni dzesimbi dzakanyungudutswa dziri mu electrolyte dzinotamira kune anode iri mu electrolyte uye dzinoisa panzvimbo yeanode muchimiro chesimbi kana munyu pasi pekugona kushoma, uye madhipoziti aya anokanganisa kugadzikana nekukora kwefirimu reSEI pane anode surface, zvichikonzera kuwedzera kwe electrode surface polarization uye kuwedzera bhatiri rekudzivirira mukati. Naizvozvo, mugumisiro wekuparara kwezvinhu zvinoshingaira pa electrolyte haibvi kubva pakuparara chete asiwo kubva kune zvimwe zvakashata zvinokonzerwa nekuparara kwesimbi inoshanduka.
Kushandiswa kweLithium Ions
Mukugadzirwa kwemabhatiri e lithium-iyoni, simba rebhatiri rinowanzoti pfuurei zvishoma pane ecathode, uye maion anodzokorodzwa e-lithium anopiwawo necathode. Naizvozvo, iyo inodzokororwa intercalation uye deintercalation yelithium ions pakati pecathode uye anode inotarisisa huwandu hwebhatiri. Munguva yekutanga yekuchaja uye yekuburitsa maitiro, iyo SEI firimu inoumbwa pane anode pamusoro. Izvo zvakakosha zveiyi passivation firimu zvakasiyana-siyana inorganic zvinhu zvakaita seLi2CO3, LiF, Li2O, LiOH uye akasiyana organic zvinhu zvakaita seROCO2Li, ROLi, uye (ROCO2) 2Li. Saka, mamwe maion lithium anopedzwa, uye kurasikirwa kwesimba uku hakugone kudzoserwa. Kuita kweanode kunodyidzana zvikuru nemaitiro uye kugadzikana kwefirimu reSEI, uye kugona kugadzira firimu reSEI rakagadzikana panzvimbo yeanode kune{12}}simba risingakodzeri pakushanda kwebhatiri. Kuumbwa kweiyo SEI firimu inopedza iyo shoma lithium ions mubhatiri. Kana iyo SEI firimu ikaramba ichikuvadzwa panguva yekutenderera, ipapo oxidation reaction pane anode / electrolyte interface icharamba ichiitika kuti iumbe SEI firimu idzva. Iyi nzira inoshandisa iyo shoma lithium ions inopiwa ne cathode muhurongwa, uye kuderedzwa kweanoshanda lithium ions kunotungamirira pakuora kwemasimba. Kudzikira kwelithium ions mu electrolyte kunokonzera kudzikira mukufambiswa kwe electrolyte, uye kurasikirwa kwe lithium ions mu cathode material kunokonzera kusaenzana pakati pema electrode maviri ebhatiri.
Kuwedzera Mukati Resistance
Munguva yakareba-kutenderera kwebhatiri, kuwedzera kwekuramba mukati ndicho chikonzero chakakosha chekuwora kwesimba. Pane zvikonzero zvakawanda zvekuwedzera kwekupikiswa kwemukati, kunyanya kubva pamativi maviri: $\\textcircled{1}$ The oxidation reaction inoitika paelectrode/electrolyte interface mu electrolyte inotungamirira kukuwedzera kwekupikisa kwemafirimu epamusoro pe electrode, uye kusagadzikana kweanode SEI firimu, kuenderera mberi kuumba mafirimu matsva epamusoro panguva yekutenderera, polarization uye zvose zvinowedzera bhatiri mukati. $\\textcircled{2}$ Kunyunguduka kwesimbi ions mu cathode kupinda electrolyte, uye yakanyungudiswa simbi ions ion kutamira anode kuburikidza electrolyte uye dhipoziti pamusoro anode pamusoro muchimiro simbi kana munyu, zvichikonzera kuwedzera electrode polarization. Mukuwedzera, tsvakurudzo yakaratidzawo kuti kuora kwemuunganidzi wemazuva ano kunogonawo kukonzera kuwedzera kwekupikisa kwemukati, asi mhedzisiro iyi idiki pasi pechirevo chekugadzirisa kwemuunganidzi wezvino. Kuwedzera kwekupikiswa kwemukati kunokonzera kuderera kwesimba uye simba, kunyanya kune anode, maitiro anoitika pa electrode / electrolyte interface ndicho chikonzero chikuru chekukwegura kweanode.
