He aha ka electrolyte i loko o ka pā lithium?
electrolyte
ʻO ka electrolyte i loko o ka lithium-ion battery ka mea lawe i nā ion i loko o ka pila. He mea maʻamau ia me nā paʻakai lithium, nā mea hoʻoheheʻe organik, a me nā mea hoʻohui, e like me ka mea i hōʻike ʻia ma ke Kiʻi 7-4. He kuleana koʻikoʻi ka electrolyte i ka hoʻokele ʻana i nā ion ma waena o nā electrodes maikaʻi a me ka ʻino o kahi pākaukau lithium{5}}ion, e hōʻoiaʻiʻo ana i kona mau pono e like me ka uila kiʻekiʻe a me ka ikehu kikoʻī kiʻekiʻe. Hoʻomākaukau maʻamau ʻia nā electrolytes ma lalo o nā kūlana kikoʻī a ma nā ʻāpana kikoʻī mai nā mea hoʻoheheʻe organik maʻemaʻe kiʻekiʻe, nā paʻakai lithium, a me nā mea hoʻohui pono. ʻOiai ʻo nā mea electrode e hoʻoholo ai i ka nui o ka ikehu o ka pākaukau, ʻo ka electrolyte ka mea e hoʻoholo pono ai i kona ola pōʻai, kiʻekiʻe a haʻahaʻa ka hana wela, a me ka palekana. ʻAʻole i loli ke ʻano kumu o ka electrolyte; Aia ka hana hou i ka hoʻomohala ʻana i nā paʻakai lithium hou a me nā mea hoʻohui, a me ka hoʻomaopopo hohonu ʻana i nā kaʻina hana kemika interfacial a me nā mīkini e pili ana i nā pā lithium-ion.
Nui nā ʻano paʻakai lithium, e like me ka mea i hōʻike ʻia ma ke Kiʻi 7-5, akā he kakaikahi wale nō ka mea i hoʻohana ʻia i nā pāʻani lithium-ion i kūʻai ʻia. Pono ka paʻakai lithium maikaʻi e loaʻa i kēia mau waiwai:
1) Degere hui haʻahaʻa, hiki ke hoʻoheheʻe ʻia i nā mea hoʻoheheʻe organik, e hōʻoia ana i ka conductivity ionic kiʻekiʻe o ka electrolyte.
2) Anions me ka antioxidant a me ka ho'ēmi kū'ē; ʻO nā huahana hōʻemi e hoʻomaʻamaʻa i ka hana ʻana i kahi kiʻiʻoniʻoni SEI kūpaʻa, haʻahaʻa haʻahaʻa.
3) Paʻa kemika maikaʻi, me ka ʻole o ka hopena o nā ʻaoʻao ʻino me nā mea electrode, electrolytes, a i ʻole nā mea hoʻokaʻawale.
4) Kaʻina hoʻomākaukau maʻalahi, kumu kūʻai haʻahaʻa, ʻaʻole-ʻawaʻawa a me ka haumia ʻole-.
ʻO LiPF6 ka paʻakai lithium i hoʻohana nui ʻia. ʻOiai ʻaʻole maikaʻi loa kāna mau waiwai ponoʻī, hōʻike ʻo ia i ka hana holoʻokoʻa maikaʻi loa i loko o nā carbonate solvent electrolytes. Loaʻa iā LiPF6 nā pōmaikaʻi nui:
1) Hiki ke hoʻoheheʻe ʻia a me ka hoʻoheheʻe ionic kiʻekiʻe i loko o nā mea hoʻoheheʻe wai ʻole.
2) Hiki iā ia ke hana i kahi kiʻiʻoniʻoni passivation paʻa ma ka ʻili o nā mea ʻohi alumini alumini.
3) Hoʻokumu ʻo ia i kahi kiʻiʻoniʻoni SEI paʻa ma ka graphite electrode surface me nā solvents carbonate.
Eia naʻe, ʻaʻohe paʻa wela maikaʻi ʻo LiPF6 a hiki i nā hopena decomposition. Hiki i nā huahana ke hoʻopōʻino i ke kiʻiʻoniʻoni SEI ma ka ʻili electrode, hoʻoheheʻe i nā mea hoʻoikaika electrode maikaʻi, a alakaʻi i ka pohō o ka hiki i ka wā kaʻa.
ʻO LiBF kekahi mea hoʻohui paʻakai lithium i hoʻohana pinepine ʻia. Hoʻohālikelike ʻia me LiPF6, ʻoi aku ka nui o ka laulā wela o ka LiBF, ʻoi aku ka maikaʻi -mahanahana paʻa, a me ka haʻahaʻa haʻahaʻa haʻahaʻa haʻahaʻa. Loaʻa i ka LiBF ka conductivity kiʻekiʻe, ka puka aniani electrochemical ākea, a me ke kūpaʻa wela maikaʻi. Aia kona pōmaika'i nui i kāna mau waiwai hana ki'i'oni'oni, no ka mea hiki iā ia ke komo pololei i ka ho'okumu 'ana i ke ki'i'oni'oni SEI.
Ma ke kumu, ua haku ʻia ʻo LiDFOB me ka hapalua-molekole o LiBOB a me LiBF, e hui pū ana i nā pono o ke kiʻiʻoniʻoni maikaʻi-ʻano waiwai o LiBOB a me ka hana haʻahaʻa haʻahaʻa maikaʻi o LiBF4. Hoʻohālikelike ʻia me LiBOB, ʻoi aku ka nui o ka solubility ʻo LiDFOB i nā mea hoʻoheheʻe carbonate linear a me ka conductivity electrolyte kiʻekiʻe. ʻOi aku ka maikaʻi o kona mahanahana kiʻekiʻe a me ka haʻahaʻa haʻahaʻa ma mua o ka LiPF4, a he ʻoluʻolu maikaʻi ia me ka cathode pākaukau, e hana ana i kahi kiʻiʻoniʻoni passivation ma ka ʻili alumini alumini a me ka pale ʻana i ka electrolyte oxidation.
ʻO nā pūʻulu CF₃SO₂ i loko o ka LiTFSI he hopena hoʻihoʻi electron -ikaika, e hoʻonui ana i ka delocalization o ka hoʻopiʻi ʻino a hoʻemi i ka hui ʻana o ka ion, e hopena i ka solubility kiʻekiʻe o ka paʻakai. Eia kekahi, he kiʻekiʻe ka hoʻoili uila ʻo LiTFSI, kahi wela wela decomposition kiʻekiʻe, a ʻaʻole maʻalahi ka hydrolyzed; akā naʻe, e hōʻino loa ia i nā mea ʻohi alumini o kēia manawa ma nā voltages ma luna o 3.7V.
ʻO nā ʻātoma fluorine i loko o ka molekele LiFSI he mau waiwai hoʻihoʻi electron -ikaika, nāna e hoʻokaʻawale i ka hoʻoili ʻino ma N, ka hopena o ka hui ʻana o nā ion nāwaliwali a me ka wehe maʻalahi o Li+, no laila ke alakaʻi nei i ka conductivity kiʻekiʻe.
Hōʻike ka LiPO2F2 i ka hana haʻahaʻa haʻahaʻa haʻahaʻa -a hoʻomaikaʻi pū i ka hana wela kiʻekiʻe o ka electrolyte. Ma ke ʻano he mea hoʻohui, hiki iā ia ke hana i kahi kiʻiʻoniʻoni SEI waiwai ma LixPOyFz a me LiF ma ka ʻili electrode maikaʻi ʻole, e kōkua ana i ka hōʻemi ʻana i ka impedance interfacial pākaukau a hoʻomaikaʻi i ka hana pōʻaiapili pākaukau. Eia naʻe, pilikia pū ka LiPO2F2 i ka haʻahaʻa haʻahaʻa.
ʻO ka mea nui o kawai electrolyteʻO ia ka mea hoʻoheheʻe organik, e hoʻoheheʻe i nā paʻakai lithium a hāʻawi i kahi mea lawe no nā ion lithium. Pono ka mea ho'ohehe'e organik maika'i no ka lithium{1}}ion electrolyte e pono e ho'okō i kēia mau kūlana:
1) Kiʻekiʻe dielectric mau a me ka ikaika dissolving hiki no nā paʻakai lithium.
2) Ka helu heheʻe haʻahaʻa a me ka helu hoʻolapalapa kiʻekiʻe, e mālama ana i kahi kūlana wai ma luna o kahi ākea ākea.
3) Haʻahaʻa viscosity, maʻalahi ka lawe ʻana i ka lithium{1}}ion.
4) Paʻa kemika maikaʻi, ʻaʻole e hōʻino i ka hoʻolālā electrode maikaʻi a i ʻole e hoʻopau i nā mea electrode maikaʻi a maikaʻi ʻole.
6
ʻO nā mea hoʻoheheʻe organik maʻamau i hoʻohana ʻia i loko o ka lithium-ion electrolytes pākahiko ua māhele nui ʻia i nā solvents carbonate a me nā solvents ether organic, e like me ka hōʻike ʻana ma ke Kiʻi 7-6. No ka loa'a -ki'eki'e o ka lithium-ion battery electrolyte, ho'ohana mau 'ia ka solvent hui 'ia i loko o 'elua a 'oi a'e ka mea ho'ohenehene, e 'ae ana ia lakou e hoopiha i kekahi i kekahi a e loaa ka hana holookoa. Hōʻike ʻia nā waiwai kino o nā mea hoʻoheheʻe carbonate maʻamau ma ka Papa 7-1.
Papa 7-1 Na Waiwai Kino o na mea hoohehee kalapona ma'amau
| Mea hoʻoheheʻe Organic | Hoʻohui Dielectric mau | Lae hehee/ degere | Lae paila/ degere | ʻO ka Coefficient Viscosity |
|---|---|---|---|---|
| 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 |
Hoʻokomo nui nā mea hoʻoheheʻe etera organik i nā etera kaulahao e like me 1,2-dimethoxypropane (DMP), dimethoxymethane (DMM), a me ka ethylene glycol dimethyl ether (DME), a me nā etera cyclic e like me tetrahydrofuran (THF) a me 2-methyltetrahydrofuran (2-Me-THF). No nā kaulahao ether solvents, ʻoi aku ka lōʻihi o ke kaulahao kalapona, ʻoi aku ka maikaʻi o ka paʻa kemika, akā ʻoi aku ka kiʻekiʻe o ka viscosity a me ka haʻahaʻa o ka neʻe ʻana o ka lithium-ion. Hiki i ka Ethylene glycol dimethyl ether ke hana i kahi chelate paʻa (LiPF6 · DME) me ka lithium hexafluorophosphate, e hōʻike ana i ka mana hoʻoheheʻe ikaika no nā paʻakai lithium a me ka hopena i ka conductivity electrolyte kiʻekiʻe. Eia nō naʻe, ʻaʻohe paʻa kemika maikaʻi ʻo DME a ʻaʻole hiki ke hana i kahi kiʻiʻoniʻoni passivation paʻa ma ka ʻili o ka mea electrode maikaʻi ʻole.
Hoʻokomo ʻia nā mea hoʻoheheʻe kalapona i nā carbonate cyclic e like me propylene carbonate (PC) a me ka ethylene carbonate (EC), a me nā carbonate kaulahao e like me dimethyl carbonate (DMC), diethyl carbonate (DEC), a me methyl ethyl carbonate (EMC). He mau dielectric kiʻekiʻe ko Cyclic carbonates, e hoʻoheheʻe ʻia ai nā paʻakai lithium, akā he kiʻekiʻe nō hoʻi ko lākou viscosity, e hopena i ka haʻahaʻa haʻahaʻa lithium{1}}ion. He haʻahaʻa ka paʻakai lithium paʻakai liʻiliʻi i nā kaulahao carbonates, akā haʻahaʻa ka viscosity a me ka hiki ke kahe maikaʻi, e hoʻomaʻamaʻa i ka neʻe ʻana o ka lithium -ion.
Hōʻike ʻia nā ʻano o nā mea hoʻohui ahi -palena no nā lithium-ion electrolytes ma ke Kiʻi 7-7. ʻO nā mea hoʻohui, hoʻohana ʻia i nā mea liʻiliʻi, loaʻa nā hopena koʻikoʻi a he ala hoʻokele waiwai a kūpono hoʻi ia no ka hoʻomaikaʻi ʻana i ka hana o nā ʻona lithium{5}}ion. Ma ka hoʻohui ʻana i kahi mea hoʻohui liʻiliʻi i ka electrolyte o nā ʻāpana lithium-ion, hiki ke hoʻomaikaʻi pono ʻia kekahi mau hiʻohiʻona hana pākaukau, e like me ka hiki ke hoʻohuli ʻia, electrode/electrolyte compatibility, hana pōʻaiapuni, hana helu, a me ka hana palekana, e pāʻani ana i kahi kuleana koʻikoʻi i nā pā lithium-ion. ʻO kahi mea hoʻohui electrolyte pākaukau lithium-ion kūpono e loaʻa i nā ʻano ʻehā:
1) High solubility i nā mea hoʻoheheʻe organik.
2) Hiki ke hoʻomaikaʻi maikaʻi ʻia kahi helu liʻiliʻi i hoʻokahi a ʻoi aku paha nā hiʻohiʻona hana.
3) ʻAʻohe hopena ʻaoʻao ʻino me nā mea ʻē aʻe e pili ana i ka hana pākaukau.
4) ʻO ke kumu kūʻai haʻahaʻa, ʻaʻole-ʻawaʻawa a haʻahaʻa paha.
Ma muli o kā lākou hana, hiki ke hoʻokaʻawale ʻia nā mea hoʻohui i loko o nā mea hoʻohui conductive, nā mea hoʻohui palekana overcharge, nā mea hoʻohui i ke ahi, nā mea hoʻohui kiʻi SEI -mea hoʻohui, nā mea pale mea cathode, LiPF6 stabilizers, a me nā mea hoʻohui hana ʻē aʻe.
Hoʻomaikaʻi nā mea hoʻohui conductive i ka wikiwiki o ka hana ʻana o nā pākahi lithium-ion ma o ka hoʻopili ʻana me nā ion electrolyte, ka hoʻoikaika ʻana i ka paʻakai lithium dissolution, a me ka hoʻonui ʻana i ka conductivity electrolyte. Ma muli o ka hana ʻana o nā mea hoʻohui conductive ma o ka coordination reactions, ua kapa ʻia lākou he ligand additives, a ua hoʻokaʻawale ʻia i loko o nā ligand anionic, nā ligands cationic, a me nā ligan neutral e pili ana i ka ion interacting.
Hāʻawi nā mea hoʻohui pale overcharge i ka pale o ka overcharge a i ʻole ka hoʻonui ʻana i ka hoʻomanawanui. Hoʻokaʻawale ʻia lākou i nā mea hoʻohui redox a me nā mea hoʻohui monomer. I kēia manawa, ʻo nā mea hoʻohui redox ka nui o ka anisole series, nona nā mana redox kiʻekiʻe a me ka solubility maikaʻi. Hoʻokomo ʻia nā mea hoʻohui monomer i nā hopena polymerization ma lalo o ka volta kiʻekiʻe, hoʻokuʻu i nā kinoea, a uhi ka polymer i ka ʻili o ka cathode, ke hoʻopau nei i ka hoʻouka ʻana. Hoʻokomo nui nā mea hoʻohui monomer i nā pūhui ʻala e like me xylene a me phenylcyclohexane.
Hana ʻia nā mea hoʻohui ahi ma ka hoʻokiʻekiʻe ʻana i ka wahi ignition o ka electrolyte a i ʻole ka hoʻopau ʻana i ke kaulahao radical manuahi e pale ai i ka puhi ʻana. Hōʻike ʻia ko lākou ʻano ma ke Kiʻi 7-8. ʻO ka hoʻohui ʻana i nā mea pale ahi kekahi o nā ala koʻikoʻi e hōʻemi i ka flammability o ka electrolyte, hoʻonui i ka pae wela o ka hana o nā pā lithium-ion, a hoʻomaikaʻi i kā lākou hana. ʻO nā hana o ka hana o ka flame retardant additives ka nui o ʻelua:
1) Ma ka hana ʻana i kahi papa insulating ma waena o ka māhele kinoea a me ka māhele condensed, pale lākou i ka puhi ʻana i nā ʻāpana condensed a me ke kinoea.
2) Hoʻopaʻa lākou i nā radical manuahi i ka wā o ka hoʻopau ʻana i ke kaʻina hana, e hoʻopau ana i ke kaulahao radical manuahi e pale ai i ka hoʻopau ʻana ma waena o nā pae kinoea.
