Intshayelelo kwi-Solid Electrolytes

 

Ii-electrolyte eziqinileyo zineenzuzo ezininzi ngaphezu kwee-electrolyte ezingamanzi. Ngokomzekelo, banokunciphisa i-electrode deformation ngexesha lokutshaja kunye nokukhupha, ukuphucula ukhuseleko. Kananjalo banozinzo olubalaseleyo, kulula ukusetyenzwa, kunye nokukhula kwelithiumiidendrites zinokucuthwa kwi-solvent{0}esiqilima se-electrolyte yepolymer esimahla.

Iibhetri zeLithium - zisebenzisa i-electrolyte yepolymer eqinileyo inokuthintela iingxaki zokuvuza ezinxulumene ne-electrolyte engamanzi.

Iipolymers kulula ukusetyenzwa kwaye zinokuthi zenziwe zincinci. Ngenxa yomgangatho weplastiki ephezulu, iipholima zisenokusetyenziswa ukwenza iibhetri zefilimu ezicekethekileyo{{1}. Ulwakhiwo lwebhetri olwahlukileyo lunokwenziwa kusetyenziswa i-polymer electrolyte ukuhlangabezana neemfuno ezahlukeneyo zosetyenziso. Ngaphaya koko, ii-electrolyte zepolymer zibonelela ngekhemikhali ephezulu, i-electrochemical, kunye nokuzinza kwe-thermal xa kuthelekiswa nee-electrolyte zolwelo, kunye neempendulo ezisecaleni ezimbalwa kunye nee-electrode kunye noluhlu olubanzi lobushushu bokusebenza. Ukuguquguquka kwe-polymer electrolytes kunokuphazamisa utshintsho lwevolumu kwii-electrode ngexesha lokutshaja kunye nokukhupha, ukuzinzisa ukwakheka kwebhetri. Ngoko ke, emva korhwebo lweebhetri ze-ion ze-lithium, i-lithium{7}}iteknoloji yebhetri ye-ion esekwe kwi-polymer electrolytes iya kukhula ngokukhawuleza kwaye ifezekise urhwebo oluyimpumelelo.

Zininzi iindlela zokuhlela i-polymer electrolytes, kwaye imigangatho iyahluka. Okwangoku, ii-electrolyte zepolymer eziqinileyo zahlulwa kakhulu ngokohlobo lwepolymer esetyenzisiweyo, njengeyona polyether idumileyo-based polyethylene oxide (PEO), kunye nepolymethyl methacrylate (PMMA) kunye nepolyacrylonitrile (PAN). Ngokubanzi, ii-electrolyte zepolymer kufuneka zihlangabezane nezi meko zilandelayo ukuze zisetyenziswe ngokwenyani kwiibhetri ze-lithium{3}}.

Kwiinkqubo zangoku ze-polymer electrolyte, iipolymers zibonisa ubucwebe obubalulekileyo kwiqondo lobushushu begumbi, nto leyo echaza ukuba kutheni ukuhanjiswa kwee-electrolyte ezomeleleyo kwiqondo lobushushu begumbi kusezantsi kakhulu kuneye-electrolyte engamanzi. Uninzi lweekristale kwiipolymers zi-spherulites, ezinemimandla ye-amorphous phakathi kwazo. Ngokuqhelekileyo kukholelwa ukuba i-lithium-i-ion conduction iyenzeka ikakhulu kule mimandla i-amorphous.

Ke ngoko, ukuqonda ubume besigaba seepolymers luncedo ekufundeni i-lithium{0}}i-ion conduction mechanism.

Kwiinkqubo ze-binary polymer electrolyte, isakhiwo sesigaba siqulethe iindidi ezimbini: imimandla yekristalline kunye nemimandla ye-amorphous. Ukuqulunqwa kwemimandla ye-crystalline iqhutywe kinetically kwaye ihambelana ngokuthe ngqo neemeko ezithile zokulungiselela kunye nexesha. Ukuthetha ngokuthe ngqo, ngenxa yobukho bemimandla ye-crystalline kwinkqubo ye-polymer, kunye nokwahluka okuphawulekayo kwale mimandla ngeemeko ezahlukeneyo, ukuthelekisa ukuqhutyelwa kweentlobo ezahlukeneyo ze-polymer electrolytes ayikho isayensi kakhulu. Nangona kunjalo, phantsi kweemeko ezithile, ukuba ukukhula kwemimandla ye-crystalline kuhamba kancinci kwaye ukuphambuka kwi-ionic conductivity kungaphakathi koluhlu olwamkelekileyo, ukuthelekisa ukuhanjiswa kuyamkeleka. Kungenxa yoko le nto sihlala sithelekisa iziphumo ezahlukeneyo.

Kuba ukukhula kwee-spherulites kwipolima kuxhomekeke-kwixesha, i-ionic conductivity kumaqondo obushushu angaphantsi kwendawo yokunyibilika yepolymer ikwaxhomekeke kwixesha-. Ngaphaya koko, i-lithium-i-ion conductivity ye-polymer electrolytes inxulumene nezinga lokufudumeza, izinga lokupholisa, kunye nexesha lokuphumla. Umzekelo, ixesha lokuphumla ixesha elide likhokelela kwisakhiwo sekristale yepolymer egcwele ngakumbi kunye nekristale ephezulu, ekhokelela ekunciphiseni ngokuthe ngcembe kwi-ionic conductivity ukuya kubuncinci kunye nokwanda kwexesha lokuphumla. Ngokufanayo, izinga lokupholisa elicothayo likhokelela kwikristali epheleleyo ngakumbi, kwaye i-ionic conductivity ehambelanayo nayo iya kuncipha ngokuthe ngcembe ukuya kubuncinci.

Funda nzulu

Ukuthatha i-binary solid polymer electrolyte ye-PEO kunye ne-LiCIO4 njengomzekelo, esi sakhiwo siqulethe izakhiwo zesigaba ezininzi. Okokuqala, i-LiClO4 kunye ne-PEO zinokwenza iikhompleksi ezahlukeneyo, kuquka i-PEO6-LiCIO4, i-PEO3-i-LiCIO4, i-PEO2-LiCIO4, kunye ne-PEO-LiClO4. Phakathi kwabo, xa i-O:Li=10:1, i-PEO6-LiCIO4 inokwenza i-eutectic kunye ne-PEO, ene-melting point ye-50 degree. Ukongezelela, xa iqondo lokushisa liphakanyiswe kwi-160 degree, i-eutectic enkulu inokusekwa. Ngethuba lenkqubo yokupholisa, i-eutectic enkulu iya kuvelisa iintlobo ezintathu ezahlukeneyo ze-spherulites: uhlobo lokuqala luyancibilika ngaphezu kwe-120℃kwaye lunomxholo ophezulu wetyuwa; uhlobo lwesibini lunyibilika phakathi kwe-45 kunye ne-60 idigri, inomlinganiselo ophantsi wetyuwa, kwaye yenza ngokukhawuleza; uhlobo lwesithathu lunendawo yokunyibilika engaphantsi kancinane kunepolymer yenginginya kwaye yenza ngokukhawuleza. Uphando kunye nohlalutyo lucebisa ukuba: uhlobo lokuqala lwe-spherulite lunokwenzeka ukuba yi-PEO3-LiCIO4; uhlobo lwesibini lunokuba ngumxube we-PEO-LiCIO4 kunye ne-PEO3-LiCIO4 complexes; kwaye uhlobo lwesithathu luhambelana ne-PEO ngokwayo. Ngaphezu koko, umxholo wetyuwa we-lithium kunye nenkqubo yokunyanga ukushisa kunokukhokelela ekutshintsheni kwesakhiwo.

Iipolymer electrolytes luhlobo lwemathiriyeli yepolymer esebenzayo ene-ionic conductivity ephezulu, eyilwe ziimpendulo ezintsonkothileyo phakathi kweepolima kunye neetyuwa zetsimbi zisebenzisa iipolima njengematrix. Ngokuxhomekeke kwi-polymer matrix, i-electrolyte yepolymer eqhelekileyo iquka i-PEO -esekelwe kwi-polymer electrolytes, i-PVDE -esekelwe kwi-polymer electrolytes, i-PMMA{3}{3}esekelwe kwi-polymer electrolytes, kunye nezinye. Ngokungafaniyo ne-inorganic solid{5}}yelizwe i-electrolyte, ii-electrolyte zepolymer zikhaphukhaphu, zinwebeka, kwaye zizinzile. Njengee-electrolyte zelizwe ezingaphiliyo eziqinileyo{7}, ii-electrolyte zepolymer aziqhubeki nje ii-ion kwiibhetri ze-lithium{8}}kodwa zikwasebenza njengezahluli zebhetri. Iipolymer electrolytes ikakhulu zineenzuzo zilandelayo:

I-complexes eyenziwe ngamatyuli e-lithium ahlukeneyo (kubandakanya i-LBF4, i-LIPF6, i-LiCFSO4, kunye ne-LiASF6) kunye ne-PEO ngokusisiseko ifana nezo zenziwe yi-LiCIO4, oku kuthetha ukuba uhlobo lwetyuwa ye-lithium alunampembelelo ngqo kuhlobo lwe-complex eyenziwe nge-PEO. Ngokukodwa, i-LiBF inokwenza iikhompleksi ezimbini ezine-PEO: PEO4-LIBF kunye ne-PEO,S{17}}LiBF. Xa umlinganiselo we-O/Li uphakathi kwe-16 kunye ne-20, i-PEO2.5 - i-LIBF4 inokwenza i-eutectic kunye ne-PEO. I-LPF6 inokwenza iikhompleksi ezimbini ezine-PEO: i-PEO6-LiPF6 kunye ne-PEO:-LiPF6. Iikhompleksi ezimbini ezenziwe yi-LiASF6 kunye ne-PEO ziyafana nezo ze-LiPF6, kodwa zineendawo eziphezulu zokunyibilika. Iityuwa ezinkulu ze-anion ze-lithium nazo zinokwenza ii-complexes kunye ne-PEO, kodwa i-kinetics icotha kakhulu. Ngapha koko, uxinzelelo lukwachaphazela ukukhula kwekristale kwinqanaba elithile. Uxinzelelo oluphezulu lukhuthaza ukukhula kwe-spherulite, kunciphisa ummandla we-amorphous, kwaye ngokuhambelanayo kunciphisa i-lithium-ion conductivity.