Ukususela ekubeni iibhetri ze-lithium-ion zangena kwiimarike, zisetyenziswe ngokubanzi ngenxa yeenzuzo zabo zobomi obude, umthamo omkhulu, kwaye akukho mpembelelo yememori. Ukusetyenziswa kweqondo lokushisa eliphantsi kweebhetri ze-lithium-ion kuneengxaki ezifana nomthamo ophantsi, ukunyanzeliswa okunzulu, ukusebenza kakubi komjikelo wokusebenza, ukubekwa kwe-lithium okucacileyo, kunye nokutsalwa kwe-lithium engalinganiyo. Nangona kunjalo, kunye nokwandiswa okuqhubekayo kweenkalo zesicelo, izithintelo ezibangelwa ukungasebenzi kakuhle kweqondo lokushisa eliphantsi kweebhetri ze-lithium-ion zibonakala ngakumbi.

Ngokweengxelo, amandla okukhutshwa kweebhetri ze-lithium-ion kwi–20 ° C kuphela malunga ne-31.5% yaloo ndawo kwiqondo lokushisa. Ubushushu bokusebenza kweebhetri zelithium-ion zemveli buphakathi kwe -20 kunye +55 °C. Nangona kunjalo, kwimimandla ye-aerospace, imboni yomkhosi, izithuthi zombane, njl., ibhetri iyadingeka ukuba isebenze ngokuqhelekileyo kwi -40 ° C. Ngoko ke, kubaluleke kakhulu ukuphucula iimpawu ezisezantsi zokushisa kweebhetri ze-Li-ion.

Factors Restricting Low Temperature Performance of Li-ion Batteries

Kwimeko yobushushu obuphantsi, i-viscosity ye-electrolyte iyanda kwaye iqina kancinci, okukhokelela ekunciphiseni kokuhanjiswa kweebhetri ze-lithium-ion.

Ukuhambelana phakathi kwe-electrolyte kunye ne-electrode engalunganga kunye ne-separator iba yimbi kwindawo yokushisa ephantsi.

I-electrode engalunganga yebhetri ye-lithium-ion ine-precipitation enzulu ye-lithium phantsi kwemekobume yobushushu obuphantsi, kwaye i-lithium yensimbi egayiweyo isabela nge-electrolyte, kunye nokubekwa kwemveliso yayo kukhokelela ekwandeni kobunzima be-solid-electrolyte interface (SEI).

Kwimeko yokushisa ephantsi, inkqubo yokusabalalisa iibhetri ze-Li-ion kwizinto ezisebenzayo ziyancipha, kwaye ukuchasana kokudluliselwa kwentlawulo (Rct) kwanda kakhulu.

Ingxoxo kwiMiba echaphazela ukusebenza koBubushushu obuphantsi beebhetri zeLi-ion

Uluvo lweengcali 1: I-electrolyte inempembelelo enkulu ekusebenzeni okuphantsi kweqondo lokushisa kweebhetri ze-lithium-ion, kwaye ukubunjwa kunye neempawu ze-physicochemical ze-electrolyte zinempembelelo ebalulekileyo ekusebenzeni okuphantsi kwebhetri. Iingxaki ezijongene nomjikelo webhetri kwiqondo lobushushu eliphantsi zezi: i-viscosity ye-electrolyte iya kwanda, kwaye isantya sokuqhuba i-ion siya kuba sicotha, okukhokelela ekungahambelani kwesantya sokufuduka kwe-electron yesekethe yangaphandle, ngoko ke ibhetri iphola kakhulu. kwaye umthamo kunye nokukhupha umthamo uyancipha ngokukhawuleza. Ngokukodwa xa utshaja kwiqondo lokushisa eliphantsi, i-lithium ion zenza ngokulula i-lithium dendrites kumphezulu we-electrode engalunganga, okubangela ukusilela kwebhetri.

Ukusebenza kobushushu obuphantsi be-electrolyte kuhambelana ngokusondeleyo nobukhulu be-conductivity ye-electrolyte ngokwayo. I-electrolyte ene-conductivity ephezulu idlulisela i-ion ngokukhawuleza kwaye inokusebenzisa amandla amaninzi kwiqondo lokushisa eliphantsi. I-lithium ityuwa ngakumbi kwi-electrolyte iyahlukana, iphezulu inani lokufuduka kwaye iphezulu i-conductivity. Iphezulu i-conductivity yombane, isantya sokuqhuba i-ion ngokukhawuleza, iyancipha i-polarization, kunye nokusebenza ngcono kwebhetri kubushushu obuphantsi. Ke ngoko, ukuhanjiswa kombane okuphezulu yimeko eyimfuneko yokufezekisa ukusebenza kakuhle kobushushu obuphantsi beebhetri ze-lithium-ion.

I-conductivity ye-electrolyte ihambelana nokubunjwa kwe-electrolyte, kwaye ukunciphisa i-viscosity ye-solvent yenye yeendlela zokuphucula ukuhanjiswa kwe-electrolyte. I-fluidity enhle ye-solvent kwiqondo lokushisa eliphantsi isiqinisekiso sothutho lwe-ion, kunye nefilimu eqinile ye-electrolyte eyenziwe yi-electrolyte kwi-electrode engafanelekanga kwiqondo lokushisa eliphantsi kwakhona isitshixo sokuchaphazela ukuqhutyelwa kwee-ion ze-lithium, kwaye i-RSEI yiyona nto iphazamisayo. iibhetri ze-lithium ion kwiindawo zobushushu obuphantsi.

Ingcaphephe ye-2: Eyona nto iphambili ekunciphiseni ukusebenza kweqondo lokushisa eliphantsi kweebhetri ze-lithium-ion kukunyuka ngokukhawuleza kwe-Li + ukumelana nokusabalalisa kumaqondo aphantsi, kungekhona ifilimu ye-SEI.

Iimpawu zokushisa eziphantsi kwezinto ze-cathode kwiibhetri ze-lithium ion

1. Iimpawu zobushushu obuphantsi bezinto eziphathekayo ze-cathode

Ulwakhiwo olunamaqabunga alunamsebenzi ongenakuthelekiswa nanto we-lithium ion diffusion channels one-dimensional, kodwa unozinzo lwesakhiwo seendlela ezintathu-dimensional. Yeyona mveliso yokuqala yecathode yorhwebo yeebhetri ze-lithium ion. Izinto zayo ezimele ziyi-LiCoO2, i-Li (Co1-xNix) i-O2 kunye ne-Li (Ni, i-Co, i-Mn) i-O2 njalo njalo.

Xie Xiaohua et al. ithathe i-LiCoO2/MCMB njengento yophando kwaye ivavanye iimpawu zayo zokukhupha intlawulo yobushushu obuphantsi.

Iziphumo zibonisa ukuba ngokuhla kweqondo lokushisa, iqonga lokukhutshwa liphuma kwi-3.762V (0 ° C) ukuya kwi-3.207V (-30 ° C); umthamo webhetri uwonke nawo wehla kakhulu ukusuka ku-78.98mA·h (0°C) ukuya kuma-68.55mA·h (–30°C).

2. Iimpawu zobushushu obuphantsi bezinto eziphathekayo ze-spinel-structured cathode

Isakhiwo se-spinel i-LiMn2O4 cathode impahla ineenzuzo zexabiso eliphantsi kunye ne-non-toxicity kuba ayinayo i-Co element.

Nangona kunjalo, ukuguquguquka kwe-valence ye-Mn kunye ne-Jahn-Teller effect ye-Mn3 + ikhokelela ekungazinzini kwesakhiwo kunye nokuguqulwa kakubi kweli candelo.

Peng Zhengshun et al. ibonise ukuba iindlela ezahlukeneyo zokulungiselela zinempembelelo enkulu ekusebenzeni kwe-electrochemical ye-LiMn2O4 cathode materials. Ukuthatha i-Rct njengomzekelo: i-Rct ye-LiMn2O4 eyenziwe ngobushushu obuphezulu-inqanaba eliqinileyo liphezulu kakhulu kunendlela ye-sol-gel, kwaye le nto ayichaphazeli i-lithium ion. I-diffusion coefficient nayo ibonakalisiwe. Isizathu kukuba iindlela ezahlukeneyo zokudibanisa zinempembelelo enkulu kwi-crystallinity kunye ne-morphology yeemveliso.

3. Iimpawu zobushushu obuphantsi bezinto ze-cathode zenkqubo ye-phosphate

Ngenxa yokuzinza komthamo obalaseleyo kunye nokhuseleko, i-LiFePO4, kunye nezixhobo ze-ternary, ibe ngumzimba oyintloko wezinto zangoku zebhetri ze-cathode. Ukusebenza kakubi kobushushu obuphantsi be-lithium iron phosphate ikakhulu kuba impahla yayo iyisigqubuthelo, ene-conductivity ephantsi ye-elektroniki, i-lithium ion diffusivity ehlwempuzekileyo, kunye ne-conductivity ephantsi kwiqondo lokushisa eliphantsi, elinyusa ukuchasana kwangaphakathi kwebhetri, echatshazelwa kakhulu. i-polarization, kunye nokutshaja kwebhetri kunye nokukhupha kuyathintelwa. Ngoko ke, iqondo lokushisa eliphantsi Ukusebenza akufanelekile.

When studying the charge-discharge behavior of LiFePO4 at low temperature, Gu Yijie et al. found that its coulombic efficiency dropped from 100% at 55°C to 96% at 0°C and 64% at -20°C, respectively; the discharge voltage decreased from 3.11V at 55°C. Decrease to 2.62V at –20°C.

Xing et al. iguqulwe i-LiFePO4 kunye ne-nanocarbon kwaye yafumanisa ukuba emva kokongeza i-agent conductive nanocarbon, ukusebenza kwe-electrochemical ye-LiFePO4 yayingaphantsi kweqondo lokushisa, kwaye iqondo lokushisa eliphantsi liphuculwe; i-voltage discharge ye-LiFePO4 ehlaziyiweyo inyuke ukusuka kwi-3.40 kwi-25 ° CV yehla ukuya kwi-3.09V kwi–25 ° C, iyancipha kuphela i-9.12%; kunye nokusebenza kwayo kweeseli kwi-25 ° C yi-57.3%, ephezulu kune-53.4% ​​ngaphandle kwe-nano-carbon conductive agent.

Kutshanje, iLiMnPO4 itsale umdla omkhulu. Uphononongo lufumene ukuba i-LiMnPO4 ineenzuzo zekhono eliphezulu (4.1V), akukho ngcoliseko, ixabiso eliphantsi, kunye nomthamo omkhulu (170mAh / g). Nangona kunjalo, ngenxa ye-ionic conductivity esezantsi ye-LiMnPO4 kune-LiFePO4, i-Fe isoloko isetyenziselwa ukufaka indawo ka-Mn ngokuyinxenye ukwenza i-LiMn0.8Fe0.2PO4 isisombululo esiqinileyo ekusebenzeni.

Iimpawu zobushushu obuphantsi bezinto ze-anode kwiibhetri ze-lithium ion

Xa kuthelekiswa nemathiriyeli ye-electrode eyakhayo, ukuwohloka kobushushu obuphantsi bezinto ezingalunganga ze-electrode ye-lithium ion ibhetri kubi kakhulu, ngakumbi ngenxa yezi zizathu zintathu zilandelayo:

Xa utshaja kwaye ukhupha kwiqondo lokushisa eliphantsi kunye nezinga eliphezulu, ibhetri i-polarized kakhulu, kwaye inani elikhulu le-lithium yensimbi ifakwe kumphezulu we-electrode engalunganga, kwaye imveliso yokusabela ye-lithium yensimbi kunye ne-electrolyte ngokubanzi ayinayo i-conductivity;

Ukusuka kwindawo yokujonga i-thermodynamic, i-electrolyte iqulethe inani elikhulu lamaqela e-polar afana ne-CO kunye ne-CN, enokuthi iphendule ngezinto ezimbi ze-electrode, kunye nefilimu eyenziwe yi-SEI iyancipha ngakumbi kwiqondo lokushisa eliphantsi;

I-carbon negative electrode inzima ukudibanisa i-lithium kwiqondo lokushisa eliphantsi, kwaye kukho intlawulo ye-asymmetric kunye nokukhutshwa.

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Uphando kwi-Electrolyte yobushushu obuphantsi

I-electrolyte idlala indima yokuthutha i-Li + kwiibhetri ze-lithium-ion, kunye ne-ionic conductivity kunye neempawu zefilimu ze-SEI zinempembelelo enkulu ekusebenzeni okuphantsi kwebhetri. Kukho izibonakaliso ezintathu eziphambili zokugweba i-pros and cons of low-temperature electrolytes: i-ionic conductivity, ifestile ye-electrochemical kunye ne-electrode reactivity. Umgangatho wezi zalathisi zintathu zixhomekeke kumlinganiselo omkhulu kwizinto ezidibeneyo: i-solvent, i-electrolyte (ityuwa ye-lithium), kunye nezongezo. Ke ngoko, uphando malunga nokusebenza kobushushu obuphantsi benxalenye nganye ye-electrolyte lubaluleke kakhulu ekuqondeni nasekuphuculeni ukusebenza kobushushu obuphantsi bebhetri.

Xa kuthelekiswa ne-carbonates ye-chain, iimpawu zokushisa eziphantsi kwe-EC-based electrolytes, i-cyclic carbonates inesakhiwo esihlangeneyo, amandla amakhulu asebenzayo, kunye nenqanaba eliphezulu lokunyibilika kunye ne-viscosity. Nangona kunjalo, i-polarity enkulu eziswa yisakhiwo seringi yenza ukuba ihlale ine-dielectric constant. I-dielectric enkulu engaguqukiyo, i-ionic conductivity ephezulu, kunye neempawu ezibalaseleyo zokwenza ifilimu ye-solvents ze-EC zithintela ngokufanelekileyo ukufakwa kwee-athomu ze-solvent, zibenza zibe yimfuneko. Ngoko ke, uninzi lweenkqubo ezisetyenziswa ngokuqhelekileyo zobushushu obuphantsi be-electrolyte zisekelwe kwi-EC, kwaye emva koko zixutywe I-molecule encinci ye-solvent enendawo yokunyibilika ephantsi.

Ityuwa yeLithium yinxalenye ebalulekileyo ye-electrolyte. Ityuwa ye-lithium kwi-electrolyte ayinakuphucula kuphela i-ionic conductivity yesisombululo, kodwa iphinde inciphise umgama wokusasazwa kwe-Li + kwisisombululo. Ngokubanzi, okukhona uxinaniso lwe-Li + kwisisombululo, lukhulu lwe-ionic conductivity. Nangona kunjalo, i-concentration ye-lithium ion kwi-electrolyte ayihambelani ngokuhambelana nokuxinana kweetyuwa ze-lithium, kodwa i-parabolic. Oku kungenxa yokuba ukuxinwa kwee-ion ze-lithium kwi-solvent kuxhomekeke kumandla okuqhawula kunye nokudibanisa i-lithium salts kwi-solvent.

Uphando kwi-Electrolyte yobushushu obuphantsi

Ukongeza ekubunjweni kwebhetri ngokwayo, izinto zenkqubo ekusebenzeni ngokwenene ziya kuba nefuthe elikhulu ekusebenzeni kwebhetri.
(1) Inkqubo yokulungiselela. Yaqub et al. Ufunde isiphumo somthwalo we-electrode kunye nobukhulu bokugquma kubushushu obuphantsi beLiNi0.6Co0.2Mn0.2O2 / iibhetri zeGraphite kwaye wafumanisa ukuba ngokubhekiselele ekugcinweni komthamo, umncinci umthwalo we-electrode kunye nokunciphisa umaleko wokugquma, ngcono uphantsi. ukusebenza kobushushu. .

(2) Ubume bentlawulo kunye nokukhutshwa. Petzl et al. wafunda isiphumo sobushushu obuphantsi kwentlawulo-yokukhutshwa kwimeko kubomi bomjikelo webhetri, kwaye wafumanisa ukuba xa ubunzulu bokukhutshwa bukhulu, kuya kubangela ilahleko enkulu yomthamo kunye nokunciphisa ubomi bomjikelo.

(3) Abanye oothunywashe. Ummandla ongaphezulu, ubungakanani bepore, ubuninzi be-electrode, ukumanzisa kwe-electrode kunye ne-electrolyte, kunye ne-separator, njl., Zonke zichaphazela ukusebenza kobushushu obuphantsi beebhetri ze-lithium-ion. Ukongezelela, impembelelo yezinto eziphathekayo kunye neziphene zenkqubo ekusebenzeni kweqondo lokushisa eliphantsi kwebhetri ayikwazi ukuhoywa.

Qinisekisa

Ukuqinisekisa ukusebenza kobushushu obuphantsi beebhetri ze-lithium-ion, la manqaku alandelayo kufuneka enziwe:

(1) Yenza ifilimu ye-SEI ebhityileyo neshinyeneyo;

(2) Qinisekisa ukuba i-Li + ine-coefficient enkulu yokusabalalisa kwizinto ezisebenzayo;

(3) I-electrolyte ine-conductivity ephezulu ye-ionic kwiqondo lokushisa eliphantsi.

Ukongeza, uphando lunokufumana enye indlela yokujonga olunye uhlobo lwebhetri ye-lithium-ion-yonke i-slid-state lithium-ion ibhetri. Xa kuthelekiswa neebhetri ze-lithium-ion eziqhelekileyo, iibhetri ze-lithium-ion zelizwe lonke, ngokukodwa iibhetri ze-lithium-ion zelizwe eziqinileyo, kulindeleke ukuba zisombulule ngokupheleleyo ingxaki yokubola kwamandla kunye nokhuseleko lomjikelo xa iibhetri zisetyenziswa. amaqondo obushushu aphantsi. c