I-graphite ihlukaniswe yaba yi-graphite yokwenziwa kanye ne-graphite yemvelo, izizinda zomhlaba eziqinisekisiwe ze-graphite yemvelo cishe amathani ayizigidi eziyizinkulungwane ezimbili.
I-graphite yokwenziwa itholakala ngokubola nokwelashwa kokushisa kwezinto eziqukethe i-carbon ngaphansi kwengcindezi evamile. Lolu shintsho ludinga izinga lokushisa eliphakeme ngokwanele namandla njengamandla okushayela, futhi isakhiwo esiphazamisekile sizoguqulwa sibe isakhiwo sekristalu ye-graphite ehlelekile.
I-Graphitization itholakala ngomqondo obanzi we-carbonaceous material ngokusebenzisa ngaphezu kuka-2000 ℃ ukuhlelwa kabusha kokushisa kwama-athomu e-carbon athomu, kodwa ezinye izinto ze-carbon ekushiseni okuphezulu okungaphezu kuka-3000 ℃ graphitization, lolu hlobo lwezinto zekhabhoni zaziwa ngokuthi "amalahle aqinile", ngoba izinto ezilula zekhabhoni ye-graphitized, indlela yendabuko ye-graphitization ihlanganisa izinga lokushisa eliphezulu kanye nendlela yokucindezela okuphezulu, i-catalytic graphitization, indlela yokubeka umhwamuko wamakhemikhali, njll.
I-Graphitization iyindlela ephumelelayo yokusetshenziswa kwenani eliphakeme kakhulu lezinto ze-carbonaceous. Ngemva kocwaningo olunzulu nolujulile olwenziwa yizazi, isivuthiwe manje. Kodwa-ke, ezinye izici ezingathandeki zikhawulela ukusetshenziswa kwe-graphitization evamile embonini, ngakho-ke kuwumkhuba ongenakugwenywa ukuhlola izindlela ezintsha ze-graphitization.
Indlela ye-electrolysis kasawoti encibilikisiwe kusukela ngekhulu le-19 yayingaphezu kwekhulu leminyaka yentuthuko, inkolelo-mbono yayo eyisisekelo nezindlela ezintsha zihlale ziqamba emisha nentuthuko, manje ayisagcini embonini yendabuko yensimbi, ekuqaleni kwekhulu lama-21, insimbi uhlelo lukasawoti oluncibilikisiwe oluqinile lwe-oxide electrolytic ukulungiswa kwezinsimbi eziyisisekelo selugxile ekusebenzeni kakhulu,
Muva nje, indlela entsha yokulungisa izinto ze-graphite nge-electrolysis kasawoti oncibilikisiwe idonse ukunaka okukhulu.
Ngokusebenzisa i-cathodic polarization kanye ne-electrodeposition, izinhlobo ezimbili ezihlukene ze-carbon raw materials ziguqulwa zibe izinto ze-nano-graphite ezinenani eliphakeme elingeziwe. Uma kuqhathaniswa nobuchwepheshe be-graphitization bendabuko, indlela entsha ye-graphitization inezinzuzo zezinga lokushisa eliphansi le-graphitization kanye ne-morphology elawulekayo.
Leli phepha libuyekeza inqubekelaphambili ye-graphitization nge-electrochemical method, lethula lobu buchwepheshe obusha, lihlaziya izinzuzo nezinkinga zalo, futhi lilindele inkambiso yalo yentuthuko yesikhathi esizayo.
Okokuqala, usawoti oncibilikisiwe we-electrolytic cathode polarization method
1.1 impahla eluhlaza
Njengamanje, impahla eluhlaza eyinhloko ye-graphite yokufakelwa iyinaliti ye-coke kanye ne-pitch coke ye-high graphitization degree, okungukuthi izinsalela zamafutha kanye netiyela yamalahle njengento eluhlaza ukukhiqiza izinto ezisezingeni eliphezulu zekhabhoni, ezine-porosity ephansi, isulfure ephansi, umlotha ophansi. okuqukethwe kanye nezinzuzo ze-graphitization, ngemuva kokulungiswa kwayo ku-graphite kunokumelana okuhle nomthelela, amandla aphezulu emishini, ukumelana okuphansi,
Kodwa-ke, ukugcinwa kukawoyela okulinganiselwe kanye nentengo kawoyela eshintshashintshayo kukhawule ukukhula kwawo, ngakho ukufuna izinto ezintsha zokusetshenziswa sekuyinkinga ephuthumayo okufanele ixazululwe.
Izindlela zendabuko ze-graphitization zinemikhawulo, futhi izindlela ezahlukene ze-graphitization zisebenzisa izinto zokusetshenziswa ezihlukile. Ngekhabhoni engeyona i-graphitized, izindlela zendabuko azikwazi ukuyidweba, kuyilapho ifomula ye-electrochemical ye-electrolysis kasawoti encibilikisiwe inqamula umkhawulo wezinto ezingavuthiwe, futhi ifanele cishe zonke izinto ezisetshenziswa ngekhabhoni yendabuko.
Izinto zekhabhoni zendabuko zifaka i-carbon black, i-activated carbon, amalahle, njll., phakathi kwamalahle okuyiwona athembisa kakhulu. Uyinki osuselwe emalahleni uthatha amalahle njengesandulela futhi ulungiselelwa emikhiqizweni yegraphite ezingeni lokushisa eliphezulu ngemva kokwelashwa kwangaphambili.
Muva nje, leli phepha lihlongoza izindlela ezintsha ze-electrochemical, ezifana ne-Peng, nge-electrolysis kasawoti encibilikisiwe akunakwenzeka ukuba i-graphitized carbon black ibe yi-crystallinity ephezulu ye-graphite, i-electrolysis yamasampuli e-graphite equkethe i-petal shape graphite nanometer chips, inezindawo eziphezulu eziqondile ezingaphezulu, lapho isetshenziselwa i-lithium battery cathode ibonise ukusebenza okuhle kakhulu kwe-electrochemical ngaphezu kwegraphite yemvelo.
UZhu et al. ifake amalahle ekhwalithi ephansi aphathwe ngekhwalithi ephansi kusistimu kasawoti encibilikisiwe ye-CaCl2 ye-electrolysis ku-950 ℃, futhi yaguqula ngempumelelo amalahle ekhwalithi ephansi abe yigraphite enobucwebe obuphakeme, obubonisa ukusebenza kahle kwezinga kanye nempilo yomjikelezo omude lapho isetshenziswa njenge-anode yebhethri ye-lithium ion. .
Ukuhlola kubonisa ukuthi kungenzeka ukuguqula izinhlobo ezahlukene zezinto zekhabhoni evamile zibe igraphite ngokusebenzisa i-electrolysis kasawoti encibilikisiwe, okuvula indlela entsha yegraphite yokwenziwa yesikhathi esizayo.
1.2 indlela ye
Indlela ye-electrolysis kasawoti encibilikisiwe isebenzisa i-carbon material njenge-cathode futhi iyiguqule ibe i-graphite enobucwebe obuphezulu ngokusebenzisa i-cathodic polarization. Njengamanje, izincwadi ezikhona zikhuluma ngokukhishwa kwe-oksijini kanye nokuhlelwa kabusha kwebanga elide lama-athomu e-carbon kunqubo yokuguqulwa okungenzeka kube yi-cathodic polarization.
Ukuba khona komoyampilo ezintweni ze-carbon kuzokhinyabeza i-graphitization ngezinga elithile. Enqubweni evamile ye-graphitization, umoya-mpilo uzosuswa kancane uma izinga lokushisa lingaphezulu kuka-1600K. Kodwa-ke, kulula kakhulu ukwenza i-deoxidize ngokusebenzisa i-cathodic polarization.
U-Peng, njll ocwaningweni okokuqala ngqa ubeka phambili indlela engaba namandla ye-electrolysis cathodic polarization kasawoti encibilikisiwe, okungukuthi i-graphitization iningi lendawo okufanele iqalwe kuzo izotholakala kusixhumi esibonakalayo se-carbon microspheres/electrolyte, ifomu lokuqala le-carbon microsphere elizungeza ububanzi obuyisisekelo obufanayo. igobolondo le-graphite, futhi angalokothi azinze ama-athomu ekhabhoni ye-anhydrous anhydrous asabalale ku-graphite flake ezinzile, aze abe yi-graphitized ngokuphelele,
Inqubo ye-graphitization ihambisana nokususwa kwe-oxygen, okubuye kuqinisekiswe ukuhlolwa.
Jin et al. futhi yafakazela leli phuzu lokubuka ngokuhlolwa. Ngemuva kwe-carbonization ye-glucose, i-graphitization (okuqukethwe kwe-oxygen engu-17%) yenziwa. Ngemva kwe-graphitization, i-carbon spheres yasekuqaleni eqinile (Fig. 1a ne-1c) yakha igobolondo elinezimbotshana elakhiwe ngama-graphite nanosheets (Fig. 1b no-1d).
Nge-electrolysis of carbon fibers (16% oxygen), ama-carbon fibers angase aguqulwe abe amashubhu e-graphite ngemva kwe-graphitization ngokusho kwendlela yokuguqula ecatshangelwe ezincwadini.
Kukholelwa ukuthi, ukunyakaza kwebanga elide kungaphansi kwe-cathodic polarization yama-athomu ekhabhoni ephezulu ye-crystal graphite kuya ku-amorphous carbon rearrange kumele kucutshungulwe, ama-synthetic graphite amacembe ayingqayizivele ama-nanostructures ahlomula ama-athomu e-oksijini avela, kodwa okuqondile indlela yokuthonya isakhiwo se-graphite nanometer akucacile, njenge-oxygen ephuma ku-carbon skeleton ngemva kokusabela kwe-cathode, njll.,
Njengamanje, ucwaningo lwemishini lusaqala, futhi ucwaningo olwengeziwe luyadingeka.
1.3 Ukwakheka kwe-morphological ye-synthetic graphite
I-SEM isetshenziselwa ukubuka i-microscopic surface morphology of graphite, i-TEM isetshenziselwa ukubuka i-morphology yesakhiwo engaphansi kuka-0.2 μm, i-XRD ne-Raman spectroscopy yizindlela ezivame ukusetshenziswa kakhulu ukuze zibonise i-microstructure ye-graphite, i-XRD isetshenziselwa ukuveza ikristalu. ulwazi lwe-graphite, kanye ne-Raman spectroscopy isetshenziselwa ukuveza amaphutha kanye ne-oda degree of graphite.
Kunezimbotshana eziningi ku-graphite ezilungiselelwe i-cathode polarization ye-electrolysis kasawoti encibilikisiwe. Ngezinto zokusetshenziswa ezihlukile, njenge-carbon black electrolysis, kutholakala ama-nanostructures anjenge-petal. Ukuhlaziywa kwe-XRD ne-Raman spectrum kwenziwa ku-carbon black ngemva kwe-electrolysis.
Ku-827 ℃, ngemva kokuphathwa nge-voltage engu-2.6V ihora elingu-1, isithombe esibukwayo se-Raman sekhabhoni emnyama sicishe sifane naleso segraphite yokuhweba. Ngemuva kokuthi i-carbon black iphathwe ngamazinga okushisa ahlukene, inani eliphakeme lesici se-graphite (002) liyalinganiswa. I-diffraction peak (002) imele izinga lokuma kwesendlalelo sekhabhoni enamakha kugraphite.
Uma ungqimba lwekhabhoni lubukhali, lubheke kakhulu.
U-Zhu usebenzise amalahle aphansi ahlanjululiwe njenge-cathode ocwaningweni, futhi i-microstructure yomkhiqizo owenziwe igraphiti yaguqulwa kusukela kugranular kuya kusakhiwo esikhulu segraphite, futhi ungqimba oluqinile lwegraphite nalo lwabonwa ngaphansi kwesibonakhulu se-electron yokudlulisela.
Ku-spectra ye-Raman, ngokushintsha kwezimo zokuhlola, inani le-ID/Ig nalo lishintshile. Lapho izinga lokushisa le-electrolytic lingu-950 ℃, isikhathi se-electrolytic sasingu-6h, futhi amandla kagesi e-electrolytic ayengu-2.6V, inani eliphansi le-ID/Ig lalingu-0.3, futhi inani eliphakeme lika-D laliphansi kakhulu kunesiqongo se-G. Ngesikhathi esifanayo, ukubukeka kwe-2D peak nakho kwakumelela ukwakheka kwesakhiwo se-graphite esihlelekile kakhulu.
Ukuphakama kwe-diffraction ebukhali (002) esithombeni se-XRD futhi iqinisekisa ukuguqulwa okuyimpumelelo kwamalahle aphansi abe yigraphite enobucwebe obuphezulu.
Enqubweni ye-graphitization, ukwanda kwezinga lokushisa kanye ne-voltage kuzodlala indima yokukhuthaza, kodwa amandla kagesi aphezulu kakhulu azonciphisa isivuno se-graphite, futhi izinga lokushisa eliphakeme kakhulu noma isikhathi eside kakhulu se-graphitization sizoholela ekumoshweni kwezinsiza, ngakho-ke ngezinto ezihlukahlukene ze-carbon. , kubaluleke kakhulu ukuhlola izimo ze-electrolytic ezifanele kakhulu, futhi ukugxila nobunzima.
Le nanostructure ye-petal-like flake inezakhiwo ezinhle kakhulu ze-electrochemical. Inombolo enkulu yama-pores ivumela ama-ion ukuthi afakwe ngokushesha / afakwe, anikeze izinto ezisezingeni eliphezulu ze-cathode zamabhethri, njll. Ngakho-ke, indlela ye-electrochemical graphitization iyindlela enamandla kakhulu ye-graphitization.
Indlela ye-electrodeposition kasawoti encibilikisiwe
2.1 I-Electrodeposition ye-carbon dioxide
Njengegesi ebamba ukushisa ebaluleke kakhulu, i-CO2 nayo iyinsiza engenabuthi, engenabungozi, eshibhile futhi etholakala kalula evuselelekayo. Nokho, ikhabhoni eku-CO2 isesimweni esiphezulu se-oxidation, ngakho-ke i-CO2 inokusimama okuphezulu kwe-thermodynamic, okwenza kube nzima ukuphinda isetshenziswe.
Ucwaningo lwakuqala lwe-CO2 electrodeposition lungalandelelwa emuva kuma-1960s. Ingram et al. kulungiswe ngempumelelo ikhabhoni ku-electrode yegolide ohlelweni lukasawoti oluncibilikisiwe lwe-Li2CO3-Na2CO3-K2CO3.
Van et al. waveza ukuthi izimpushana zekhabhoni ezitholwe ngamakhono ahlukene okunciphisa zinezakhiwo ezihlukene, okuhlanganisa i-graphite, i-amorphous carbon kanye ne-carbon nanofibers.
Ngosawoti oncibilikisiwe ukubamba i-CO2 kanye nendlela yokulungiselela impumelelo yezinto zekhabhoni, ngemva kwesikhathi eside izazi zocwaningo ziye zagxila endleleni yokwakheka kwe-carbon deposition kanye nomphumela wezimo ze-electrolysis kumkhiqizo wokugcina, okuhlanganisa izinga lokushisa le-electrolytic, i-electrolytic voltage kanye nokwakheka usawoti oncibilikisiwe nama-electrode, njll., ukulungiswa kokusebenza okuphezulu kwezinto zegraphite ze-electrodeposition ye-CO2 kuye kwabeka isisekelo esiqinile.
Ngokushintsha i-electrolyte nokusebenzisa uhlelo lukasawoti oncibilikisiwe olusekelwe ku-CaCl2 olunamandla okuthwebula i-CO2, u-Hu et al. i-graphene elungiswe ngempumelelo ene-graphitization degree ephezulu kanye ne-carbon nanotubes nezinye izakhiwo ze-nanographite ngokufunda izimo ze-electrolytic ezifana nezinga lokushisa le-electrolysis, ukwakheka kwe-electrode kanye nokwakheka kukasawoti oncibilikisiwe.
Uma kuqhathaniswa nesistimu ye-carbonate, i-CaCl2 inezinzuzo zokushibhile nokutholakala kalula, ukuhanjiswa okuphezulu, ukuncibilika kalula emanzini, kanye nokuncibilika okuphezulu kwama-ion oksijini, ahlinzeka ngezimo zethiyori zokuguqulwa kwe-CO2 ibe yimikhiqizo ye-graphite enenani eliphakeme elingeziwe.
2.2 Indlela Yokuguqula
Ukulungiswa kwe-value-added carbon materials nge-electrodeposition ye-CO2 esuka kusawoti oncibilikisiwe ikakhulukazi kuhlanganisa ukubanjwa kwe-CO2 nokunciphisa okungaqondile. Ukuthwebula i-CO2 kuqedwa nge-O2- kusawoti oncibilikisiwe wamahhala, njengoba kukhonjisiwe ku-Equation (1) :
CO2+O2-→CO3 2- (1)
Njengamanje, izindlela ezintathu zokusabela zokunciphisa ngokungaqondile ziye zahlongozwa: ukusabela kwesinyathelo esisodwa, ukusabela kwezinyathelo ezimbili kanye nendlela yokusabela yokunciphisa insimbi.
Indlela yokusabela eyisinyathelo esisodwa yaqale yahlongozwa ngu-Ingram, njengoba kukhonjisiwe ku-Equation (2) :
CO3 2-+ 4E – →C+3O2- (2)
Indlela yokusabela eyizinyathelo ezimbili yahlongozwa ngu-Borucka et al., njengoba kukhonjisiwe ku-Equation (3-4) :
CO3 2-+ 2E – →CO2 2-+O2- (3)
CO2 2-+ 2E – →C+2O2- (4)
Indlela yokusabela kokunciphisa insimbi yahlongozwa nguDeanhardt et al. Babekholelwa ukuthi ama-ion ensimbi aqale ancishiswa abe yinsimbi ku-cathode, bese insimbi yehliswa ibe yi-carbonate ion, njengoba kuboniswe ku-Equation (5~6) :
M- + E – →M (5)
4 m + M2CO3 – > C + 3 m2o (6)
Njengamanje, indlela yokusabela yesinyathelo esisodwa ngokuvamile iyamukelwa ezincwadini ezikhona.
Yin et al. yafunda isistimu ye-carbonate ye-Li-Na-K ene-nickel njenge-cathode, i-tin dioxide njenge-anode nentambo yesiliva njenge-reference electrode, futhi yathola isibalo sokuhlola i-voltammetry ye-cyclic ku-Figure 2 (isilinganiso sokuskena esingu-100 mV/s) ku-nickel cathode, futhi yatholakala. ukuthi kube nesiqongo esisodwa kuphela sokunciphisa (ku--2.0V) ekuskeneni okunegethivu.
Ngakho-ke, kungaphethwa ngokuthi ukusabela okukodwa kuphela okwenzeka ngesikhathi sokunciphisa i-carbonate.
Gao et al. ithole i-voltammetry ye-cyclic efanayo ohlelweni olufanayo lwe-carbonate.
Thola et al. isebenzise i-anode ye-inert kanye ne-tungsten cathode ukuze ithwebule i-CO2 ohlelweni lwe-LiCl-Li2CO3 futhi yathola izithombe ezifanayo, futhi inani eliphakeme kuphela lokunciphisa lokufakwa kwekhabhoni elivele ekuskeneni okunegethivu.
Ohlelweni lukasawoti oluncibilikisiwe lwensimbi ye-alkaline, izinsimbi ze-alkali ne-CO zizokhiqizwa ngenkathi ikhabhoni ifakwa yi-cathode. Kodwa-ke, ngenxa yokuthi izimo ze-thermodynamic zokusabela kwe-carbon deposition ziphansi ezingeni lokushisa eliphansi, ukuncipha kwe-carbonate kuya ku-carbon kuphela okungatholwa ocwaningweni.
2.3 CO2 bamba ngosawoti oncibilikisiwe ukuze kulungiswe imikhiqizo ye-graphite
I-graphite nanomatadium enenani eliphakeme njenge-graphene ne-carbon nanotubes ingalungiswa nge-electrodeposition ye-CO2 kusawoti oncibilikisiwe ngokulawula izimo zokuhlola. Hu et al. isebenzise insimbi engagqwali njenge-cathode ohlelweni lukasawoti oluncibilikisiwe lwe-CaCl2-NaCl-CaO futhi yafakwa ugesi amahora angu-4 ngaphansi kwesimo se-voltage engaguquki engu-2.6V emazingeni okushisa ahlukene.
Ngenxa ye-catalysis yensimbi kanye nomphumela wokuqhuma we-CO phakathi kwezingqimba ze-graphite, i-graphene yatholakala ebusweni be-cathode. Inqubo yokulungiselela i-graphene iboniswa ku-Fig. 3.
Isithombe
Ucwaningo lwakamuva lwengeze i-Li2SO4 ngesisekelo sohlelo lukasawoti oluncibilikisiwe lwe-CaCl2-NaClCaO, izinga lokushisa kwe-electrolysis lalingu-625 ℃, ngemva kwehora le-4 le-electrolysis, ngesikhathi esifanayo ekufakweni kwe-cathodic ye-carbon yathola i-graphene ne-carbon nanotubes, ucwaningo lwathola ukuthi i-Li+ ne-SO4 2 - ukuletha umphumela omuhle ku-graphitization.
Isibabule siphinde sihlanganiswe ngempumelelo emzimbeni wekhabhoni, futhi amashidi e-graphite ama-ultra-thin kanye ne-filamentous carbon angatholakala ngokulawula izimo ze-electrolytic.
Izinto ezifana namazinga okushisa e-electrolytic aphezulu naphansi ekubunjweni kwe-graphene kubalulekile, lapho izinga lokushisa elingaphezu kuka-800 ℃ kulula ukukhiqiza i-CO esikhundleni sekhabhoni, cishe akukho carbon deposition lapho ingaphezulu kuka-950 ℃, ngakho-ke ukulawula izinga lokushisa kubaluleke kakhulu. ukukhiqiza i-graphene ne-carbon nanotubes, nokubuyisela isidingo sokusabela kwe-carbon deposition reaction CO reaction ukuze kuqinisekiswe ukuthi i-cathode ikhiqiza i-graphene ezinzile.
Le misebenzi inikeza indlela entsha yokulungiswa kwemikhiqizo ye-nano-graphite nge-CO2, ebaluleke kakhulu ekuxazululeni amagesi abamba ukushisa kanye nokulungiswa kwe-graphene.
3. Isifinyezo kanye ne-Outlook
Ngokuthuthuka okusheshayo kwemboni yamandla amasha, i-graphite yemvelo ayikwazanga ukuhlangabezana nesidingo samanje, futhi i-graphite yokwenziwa inezakhiwo ezingcono zomzimba namakhemikhali kune-graphite yemvelo, ngakho-ke i-graphitization eshibhile, ephumelelayo futhi enobungani bemvelo ingumgomo wesikhathi eside.
Izindlela ze-electrochemical graphitization ezintweni ezingavuthiwe eziqinile neziyigesi ngendlela ye-cathodic polarization kanye ne-electrochemical deposition iphume ngempumelelo ezintweni zegraphite ezinenani eliphakeme elingeziwe, uma kuqhathaniswa nendlela yendabuko ye-graphitization, indlela ye-electrochemical isebenza kahle kakhulu, ukusetshenziswa kwamandla okuphansi, ukuvikelwa kwemvelo okuluhlaza, okuncane okukhawulelwe ngezinto ezikhethiwe ngasikhathi sinye, ngokuya ngezimo ezahlukahlukene ze-electrolysis kungalungiswa nge-morphology ehlukene yesakhiwo segraphite,
Inikeza indlela ephumelelayo yazo zonke izinhlobo ze-amorphous carbon kanye namagesi abamba ukushisa ukuze ziguqulwe zibe izinto ezibalulekile ze-nano-structured graphite futhi zinethuba elihle lokufaka isicelo.
Njengamanje, lobu buchwepheshe buyaqala. Kukhona izifundo ezimbalwa mayelana ne-graphitization nge-electrochemical method, futhi kusenezinqubo eziningi ezingaziwa. Ngakho-ke, kuyadingeka ukuqala ezintweni ezingavuthiwe futhi wenze ucwaningo olunzulu futhi oluhlelekile kumakhabhoni ahlukahlukene amorphous, futhi ngesikhathi esifanayo uhlole i-thermodynamics kanye ne-dynamics yokuguqulwa kwegraphite ezingeni elijulile.
Lezi zinokubaluleka okufinyelele kude ekuthuthukisweni kwesikhathi esizayo kwemboni ye-graphite.
Isikhathi sokuthumela: May-10-2021