Chii chinonzi electrolyte mubhatiri re lithium?
electrolyte
Electrolyte mubhatiri relithium-inotakura maion mubhatiri. Inowanzo umbwa nelithium salts, organic solvents, uye additives, sezvinoratidzwa mumufananidzo 7-4. Electrolyte inoita basa rakakosha pakuitisa maion pakati pemaelectrode akanaka neasina kunaka ebhatiri relithium-, kuona zvazvakanakira zvakaita semagetsi akakwira uye simba rakanyanya. Electrolytes anogaro gadzirwa pasi pemamiriro chaiwo uye muzvikamu zvakasiyana kubva pakakwirira-kuchena organic zvinonyungudutsa, lithium munyu, uye zvinodiwa zvinowedzerwa. Nepo zvinhu zve electrode zvichitaridza kuwanda kwesimba rebhatiri, iyo electrolyte inotarisisa hupenyu hwayo hwekutenderera, yakakwirira uye yakaderera tembiricha kuita, uye kuchengetedzeka. Iyo yakakosha kuumbwa kwe electrolyte inoramba isingachinjiki; innovation inonyanya kuve mukugadzirwa kweinoveli lithium salts uye additives, pamwe nekunzwisisa kwakadzama kwe interfacial chemical process uye nzira dzinobatanidzwa mumabhatiri e-lithium-ion.
Kune mhando dzakawanda dzelithium munyu, sezviri kuratidzwa paMufananidzo 7-5, asi mashoma anoshandiswa mumabhatiri e-lithium-ion anotengeswa. Iyo yakanaka lithium munyu inofanirwa kuve neinotevera zvivakwa:
1) Yakaderera dhigirii yemubatanidzwa, inonyungudika zviri nyore muorganic solvents, kuve nechokwadi chepamusoro ionic conductivity ye electrolyte.
2) Anions ane antioxidant uye kuderedza kuramba; zvigadzirwa zvinoderedza zvinofambisa kugadzirwa kwefirimu rakagadzikana, rakaderera-reresistance SEI.
3) Kugadzikana kwakanaka kwemakemikari, pasina kukonzeresa maitiro anokuvadza nemagetsi emagetsi, electrolytes, kana separators.
4) Magadzirirwo ari nyore, mutengo wakaderera,-usiri muchetura uye unosvibisa-mahara.
LiPF6 ndiyo inonyanya kushandiswa lithium munyu. Nepo zvimiro zvayo zvega zvisiri izvo zvakanyanya kushamisira, inoratidza zvakaringana kuita kwese mu carbonate yakasanganiswa solvent electrolytes. LiPF6 ine zvinotevera zvakakosha mabhenefiti:
1) Suitable solubility uye high ionic conductivity mune zvisiri-zvinonyungudutsa zvine aqueous.
2) Inogona kuumba yakagadzikana passivation firimu pamusoro pearuminiyamu foil ikozvino vateresi.
3) Iyo synergistically inoumba yakagadzikana SEI firimu pane graphite electrode pamusoro ne carbonate solvents.
Nekudaro, LiPF6 haina kugadzikana kwemafuta uye inowanzoitika pakuora maitiro. Byproducts inogona kukuvadza iyo SEI firimu pane electrode pamusoro, kunyungudutsa yakanaka electrode inoshanda zvikamu, uye zvinotungamira mukuora kwesimba panguva yebhasikoro.
LiBF zvakare inowanzoshandiswa lithium munyu yekuwedzera. Kana ichienzaniswa neLiPF6, LiBF ine tembiricha yakatambanuka, -kugadzikana kwematembiricha zviri nani, uye-kudzikira kwakanyanya. LiBF ine yakakwira conductivity, yakafara electrochemical hwindo, uye yakanaka kugadzikana kwemafuta. Kubatsira kwayo kukuru kuri mufirimu-yayo kugadzira zvivakwa, sezvo ichikwanisa kutora chikamu mukugadzirwa kwefirimu reSEI.
Zvichienderana nemaitiro, LiDFOB inoumbwa nehafu{{0}mamorekuru eLiBOB neLiBF, achibatanidza zvakanakira firimu rakanaka-kuumba zvimiro zveLiBOB uye kudzika kwakanaka-kunoitwa kweLiBF4. Kuenzaniswa neLiBOB, LiDFOB ine yakanyanya kunyungudika mumutsara kabhoni zvinonyungudutsa uye yakakwirira electrolyte conductivity. Kukwirisa-kwayo nekudzikira-kuita kwayo kuri nani pane LiPF4, uye inoenderana zvakanaka nebhatiri cathode, ichiita firimu rekufambisa paaruminiyamu foil uye inodzivirira electrolyte oxidation.
Mapoka eCF₃SO₂ ari muchimiro cheLiTFSI ane erekitironi yakasimba-yekubvisa mhedzisiro, iyo inowedzera kubviswa kwechaji isina kunaka uye inoderedza kubatanidzwa kweion, zvichikonzera kunyungudika kwakanyanya kwemunyu. Uyezve, LiTFSI ine yakakwirira yemagetsi conductivity, yakakwira yekupisa yekuora tembiricha, uye haisi nyore hydrolyzed; zvisinei, ichaita corrode zvakaipisisa aruminiyamu vaunganidzi vari voltages pamusoro 3.7V.
Maatomu efluorine ari muMokurukuru weLiFSI ane maerekitironi akasimba{{0}anoita zvekubvisa, izvo zvinobvisa chaji isina kunaka paN, zvichikonzera kubatana kwemaion uye kupatsanurwa kuri nyore kweLi+, zvichizotungamira mukufambiswa kwepamusoro.
LiPO2F2 inoratidza kuita kwakanaka kwakadzikira-uye inonatsiridza-tembiricha yepamusoro ye electrolyte. Sekuwedzera, inogona kuumba firimu reSEI rakapfuma muLixPOyFz uye LiF pane yakashata electrode pamusoro, iyo inobatsira kudzikisa bhatiri interfacial impedance uye kunatsiridza bhatiri kutenderera kuita. Nekudaro, LiPO2F2 zvakare inotambura nekushomeka solubility.
Chikamu chikuru chemvura electrolytendiyo organic solvent, iyo inonyungudutsa lithium munyu uye inopa mutakuri welithium ions. Mushonga wakanaka wekunyungudutsa welithium-ion bhatiri electrolyte inoda kuzadzisa zvinotevera:
1) Yakakwira dielectric inogara uye yakasimba kunyungudutsa kugona kwelithium munyu.
2) Nzvimbo yakaderera yekunyungudika uye nzvimbo yakakwira yekubikira, kuchengetedza nzvimbo yemvura pane yakakura tembiricha renji.
3) Low viscosity, kufambisa lithium-ion transport.
4) Kugadzikana kwakanaka kwemakemikari, hakukuvadzi chimiro chakanaka uye chisina kunaka che electrode kana kunyungudutsa zvinhu zvakanaka uye zvisina kunaka zve electrode.
5) Flash point yepamusoro, chengetedzo yakanaka, mutengo wakaderera, usinga{{1}uchetura uye usingasvibisi-.
Zvinonyungudutsa zvakajairika zvinoshandiswa mu lithium-ion bhatiri maelectrolyte anonyanyopatsanurwa kuita carbonate solvents uye organic ether solvents, sezviri kuratidzwa paMufananidzo 7-6. Kuti muwane-yakanyanya kushanda lithium-ion bhatiri electrolyte, musanganiswa wekunyungudutsa une zviviri kana kudarika zvinonyungudutsa zveorganic zvinowanzo shandiswa, zvichizvibvumira kuti zviwirirane uye kuita basa ririnani rose. Zvinhu zvemuviri zvezvakajairwa carbonate solvents zvinoratidzwa muTebhurari 7-1.
Tafura 7-1 Zvinhu Zvenyama zveCommon Carbonate Solvents
| Organic Solvent | Relative Dielectric Constant | Melting Point / degree | Boiling point/ degree | Viscosity Coefficient |
|---|---|---|---|---|
| Ethylene Carbonate (EC) | 89.6 | 37 | 243 | 1.86 |
| Propylene Carbonate (PC) | 64.4 | -55 | 240 | 2.53 |
| Dimethyl Carbonate (DMC) | 0.59 | 2 | 91 | 0.59 |
| Diethyl Carbonate (DEC) | 2.8 | -43 | 126 | 0.75 |
| Ethyl Methyl Carbonate (EMC) | 3.0 | -53 | 108 | 0.65 |
Organic ether zvinonyungudutsa zvinonyanya zvinosanganisira cheni ethers dzakadai se1,2-dimethoxypropane (DMP), dimethoxymethane (DMM), uye ethylene glycol dimethyl ether (DME), uye ethers ecyclic senge tetrahydrofuran (THF) uye 2-methyltetra-Methylfuran (2-). Pamaketani ether zvinonyungudutsa, kureba kweketani yekabhoni, zviri nani kugadzikana kwekemikari, asi iyo yakakwirira viscosity uye yakaderera iyo lithium-ion migration rate. Ethylene glycol dimethyl ether inogona kuumba chelate yakanyatsogadzikana (LiPF6 · DME) ine lithium hexafluorophosphate, ichiratidza simba rakasimba rekunyunguduka reti lithium salt uye zvichiita kuti pave nepamusoro pe electrolyte conductivity. Nekudaro, DME haina kugadzikana kwemakemikari uye haigone kugadzira yakagadzikana passivation firimu pamusoro peiyo yakaipa electrode zvinhu.
Carbonate solvents zvinosanganisira cyclic carbonates senge propylene carbonate (PC) uye ethylene carbonate (EC), uye cheni carbonates senge dimethyl carbonate (DMC), diethyl carbonate (DEC), uye methyl ethyl carbonate (EMC). Cyclic carbonates ine dielectric constant yakakwira, zvichiita kuti lithium salt inyunguke, asi ine viscosity yakakwirira, zvichikonzera kudzikira kwelithium-ion migration rate. Chain carbonates ine dielectric yakaderera uye isina simba lithium salt solubility, asi yakaderera viscosity uye yakanaka kuyerera, zvichiita kuti lithium-ion ifambe.
Mhando dzemurazvo-zvinodzoreredza zvinowedzerwa zvelithium-ion electrolytes inoratidzwa paMufananidzo 7-7. Zvinowedzerwa, zvinoshandiswa zvishoma, zvine mhedzisiro yakakura uye inzira ine mari uye inoshanda yekuvandudza kushanda kwemabhatiri e lithium-ion. Nekuwedzera chidimbu chidiki chezvinowedzerwa kuelectrolyte yelithium-mabhatiri eion, mamwe maitiro ebhatiri anogona kunyatsonatsiridzwa, senge reversible capacity, electrode/electrolyte comppatibility, cycle performance, rate performance, and safety performance, kutamba basa rakakosha mu lithium-mabhatiri eion. Yakanakira lithium-ion bhatiri electrolyte yekuwedzera inofanirwa kuve neanotevera maitiro mana:
1) High solubility mune organic solvents.
2) Mari shoma inogona kuvandudza zvakanyanya imwe kana kupfuura maitiro ekuita.
3) Hapana maitiro anokuvadza emativi ane zvimwe zvikamu zvebhatiri zvinokanganisa kushanda kwebhatiri.
4) Mutengo wakaderera,-usiri muchetura kana muchetura wakaderera.
Zvichienderana nebasa razvo, zvinowedzerwa zvinogona kuiswa muzvikamu zvezvinokonzeresa, zvinodzivirira zvakawandisa, zvinodzoreredza murazvo, SEI firimu-kuumba additives, cathode material protectants, LiPF6 stabilizers, uye zvimwe zvinoshanda additives.
Maconductive additives anovandudza mashandiro emabhatiri e-lithium-eion kuburikidza nekubatanidza maion e electrolyte, kukurudzira kuparara kwelithium munyu, uye kuwedzera kufambisa kwe electrolyte. Nokuti conductive additives inoshanda kuburikidza nekugadzirisa maitiro, anonziwo ligand additives, uye akaiswa muanionic ligands, cationic ligands, uye neutral ligands zvichienderana neion inopindirana.
Overcharge dziviriro yekuwedzera inodzivirira kuwandisa kana kuwedzera kushivirira kwechaji. Iwo anoshanda akakamurwa kuita redox additives uye monomer additives. Parizvino, redox additives inonyanya kuteedzera anisole, ine yakakwira redox mikana uye yakanaka solubility. Monomer additives inosangana nepolymerization reactions pasi pemhepo yakakwira, inoburitsa magasi, uye iyo polymer inopfeka iyo cathode zvinhu pamusoro, ichikanganisa kuchaja. Monomer additives kunyanya zvinosanganisira zvinhu zvinonhuhwirira zvakaita sexylene uye phenylcyclohexane.
Flame retardant additives inoshanda nekusimudza iginition point ye electrolyte kana kumisa iyo free radical chain reaction inodzivirira kupisa. Mhando dzavo dzinoratidzwa mumufananidzo 7-8. Kuwedzera zvinodzosa moto ndiyo imwe yenzira dzakakosha dzekudzikisa kupisa kweelectrolyte, kuwedzera tembiricha yekushandisa yemabhatiri e-lithium-ion, nekuvandudza mashandiro avo. Maitiro ekuita kweflame retardant additives anonyanya kuita maviri:
1) Nekugadzira insulating layer pakati pechikamu chegasi uye chikamu chakafukidzwa, vanodzivirira kupisa mune zvese zvakapfupikiswa uye gasi nhanho.
2) Ivo vanotora mahara radicals panguva yekupisa reaction process, kumisa iyo yemahara radical chain reaction iyo inhibits conmbustion reactions pakati pegasi phases.
