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 ingokomqondo obanzi wezinto ze-carbonaceous ezingaphezu kuka-2000 ℃ ukulungiswa kabusha kokushisa kokushisa okuphezulu kwama-athomu e-carbon, nokho ezinye izinto ze-carbon ekushiseni okuphezulu okungaphezu kuka-3000 ℃ graphitization, lolu hlobo lwezinto zekhabhoni zaziwa ngokuthi "amalahle aqinile", ukuze kube lula i-graphitized carbon athomu, indlela yendabuko ye-graphitization, indlela yokucindezela amakhemikhali aphezulu, i-graphitization ephezulu yendlela yokushisa ihlanganisa indlela yokufaka, 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 encibilikisiwe ye-electrolysis kasawoti kusukela ngekhulu le-19 yayingaphezu kwekhulu leminyaka yentuthuko, inkolelo-mbono yayo eyisisekelo nezindlela ezintsha zihlala zishintsha futhi zithuthuka, manje azisanqunyelwe embonini yensimbi yendabuko, ekuqaleni kwekhulu lama-21, insimbi ohlelweni oluncibilikisiwe lukasawoti oluqinile lwe-oxide electrolytic ukulungiswa kwezinsimbi eziyisisekelo sekugxilwe kakhulu 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 eyinhloko eluhlaza ye-graphite yokufakelwa iyinaliti ye-coke kanye ne-pitch coke yezinga eliphezulu le-graphitization, okungukuthi izinsalela zamafutha kanye netiyela lamalahle njengento eluhlaza ukukhiqiza izinto ezisezingeni eliphezulu zekhabhoni, ezine-porosity ephansi, isibabule esiphansi, okuqukethwe komlotha ophansi kanye nezinzuzo ze-graphitization, ngemuva kokulungiswa kwayo ku-graphite, ukumelana nokuqina, ukumelana nomthelela omuhle, ukumelana nokuqina, ukumelana nokuqina, ukumelana nokuqina.
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, lapho isetshenziselwa ibhethri ye-lithium 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 obuphezulu, obubonisa ukusebenza kahle kwesilinganiso 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 khona ye-electrolysis cathodic polarization kasawoti encibilikisiwe, okungukuthi i-graphitization iningi lendawo ongaqala kuyo kufanele ibekwe ku-carbon microspheres/electrolyte interface, ifomu lokuqala le-carbon microsphere elizungeze igobolondo legraphite eliyisisekelo elifanayo, futhi angalokothi azinze ama-athomu ekhabhoni ye-anhydrous e-anhydrous asakazeke kuze kube i-flaggraph eqinile 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 ye-carbon athomu ephezulu ye-crystal graphite kuya ku-amorphous carbon rearrange kumele icubungule, i-synthetic graphite amacembe ayingqayizivele ama-nanostructures ahlomula ama-athomu omoya-mpilo kusuka, kodwa okuqondile indlela yokuthonya isakhiwo se-graphite nanometer akucacile, njenge-oksijini evela ku-carbon skelede emva kokusabela kwe-cathokelede, 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 ulwazi lwekristalu lwegraphite, kanti i-Raman isetshenziselwa i-spectroscopy ye-spectroscopy.
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 eliphezulu kakhulu noma isikhathi eside kakhulu se-graphitization kuzoholela ekumoshweni kwezinsiza, ngakho-ke ezintweni ezihlukene zekhabhoni, kubaluleke kakhulu ukuhlola izimo ezifanele kakhulu ze-electrolytic, 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 socwaningo izazi ziye zagxila endleleni yokwakheka kwe-carbon deposition kanye nomphumela wezimo ze-electrolysis kumkhiqizo wokugcina, ohlanganisa izinga lokushisa le-electrolytic, i-electrolytic voltage kanye nokwakheka kukasawoti oncibilikisiwe kanye nama-electrode, njll., ukulungiswa kokusebenza okuphezulu kwe-graphite materials for 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 yathola ukuthi kunezinga eliphezulu elilodwa kuphela lokunciphisa (ku- -2.0V ukuskena) 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 lwengeza 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-graphit.
Isibabule siphinde sihlanganiswe ngempumelelo emzimbeni wekhabhoni, futhi amashidi e-graphite ama-ultra-thin kanye ne-filamentous carbon angatholakala ngokulawula izimo ze-electrolytic.
Izinto ezifana nokushisa kwe-electrolytic ephakeme naphansi ekubunjweni kwe-graphene kubalulekile, lapho izinga lokushisa elingaphezulu kuka-800 ℃ kulula ukukhiqiza i-CO esikhundleni sekhabhoni, cishe akukho carbon deposition lapho ingaphezu kuka-950 ℃, ngakho-ke ukulawulwa kwezinga lokushisa kubaluleke kakhulu ukukhiqiza i-graphene ne-carbon nanotubes, nokubuyisela isidingo sokusabela kwe-carbon deposition reaction CO-reaction synergy ukuze kuqinisekiswe ukuthi i-synergy synergy.
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 zokusetshenziswa eziqinile neziyigesi ngendlela ye-cathodic polarization kanye ne-electrochemical deposition yaphuma ngempumelelo ezintweni zegraphite ezinenani eliphakeme elingeziwe, uma kuqhathaniswa nendlela yendabuko ye-graphitization, indlela ye-electrochemical isezingeni eliphakeme kakhulu, ukusetshenziswa kwamandla okuphansi, ukuvikelwa kwemvelo okuluhlaza, okuncane okukhawulelwe ngezinto ezikhethiwe ngasikhathi sinye, ngokuya ngesakhiwo se-electrolysis ehlukene, ingalungiswa nge-morphology ehlukene yegrafu.
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