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 In Hyuk Son Jong Hwan Park Soonchul Kwon Seongyong Park Mark H. Rümmeli Alicja Bachmatiuk Hyun Jae Song Junhwan Ku Jang Wook Choi Jae-man Choi Seok-Gwang Doo Hyuk Chang Isishwawulo I-Silicon iyathola ingqalelo njengento esebenzayo kuma-anode ebhetri elandelayo yesizukulwana solayithiyoni-ion ngenxa yomthamo wayo omkhulu wegravimetric. Nangona kunjalo, utshintsho olukhulu lwevolumu ye-silicon ngexesha lokutshaja–ukukhutshwa kwesekethe liyayenza ingangqinelani kwididadi yamandla evolumetric kunye nobomi besekethe. Apha sixela ukukhula okuqondileyo kwe-graphene phezu kwe-silicon nanoparticles ngaphandle kokwakheka kwe-silicon carbide. Imilawu ye-graphene ekhaphazeleke phezu komhlaba we-silicon iyakukhuthaza ukwanda kwevolumu ye-silicon ngohlobo lokuhambelana phakathi kwemilawu ye-graphene elandelanayo. Xa idityaniswe ne-cathode ye-lithium cobalt oxide eshishini, i-graphene coating engenayo i-silicon carbide ivumela isuntsu eligcweleyo ukuba lifikelele kwii-dadi zamandla evolumetric ze-972 kunye ne-700 Wh l−1 kwi-cycle yokuqala kunye neye-200, ngokulandelanayo, 1.8 kunye ne-1.5 amaxesha aphezulu kunezo zebhetri ezishishini zolayithiyoni-ion. Oku kungqina ukuba isakhiwo esijonge phantsi somhlaba we-graphene kunye nokudityaniswa kwayo okungenayo i-silicon carbide kunye ne-silicon kungasebenza njengomzekelo ekudala kwenziwe kwii-anode ze-silicon zitshone kwitekhnoloji esebenzayo.  Intshayelelo Umthamo wegravimetric wetheoritikali we-silicon (Si) ufikelela kwi-4,000 mAh g−1. Eli xabiso lingathelekisekiyo liye layikhuthaza ingingqi yebhetri ukuba ichithe imizamo emininzi yophando kuba umthamo omkhulu wegravimetric uvumela ukuba wandiswe iidadi zamandla e-lithium-ion batteries (LIBs) kakhulu, ngaloo ndlela izise izicelo ze-LIB zexesha elizayo, ezinje ngeemoto zombane, kwisimo sangempela , , , , . Kwiminyaka elishumi elidlulileyo, iintlobo ezahlukeneyo zezakhiwo ze-electrode eziphuculweyo , , , , , , , , , ,  kunye nezinto eziqinisa i-electrode , ,  kwenziwa ukuze kusonjululwe iingxaki zokuncipha komthamo rhoqo ezivela ekwanda okukhulu kwevolumu ye-Si, okuholela ekwenzeni kakuhle okubalulekileyo kwiminyaka elishumi elinesibini . Ngaphandle kwexabiso le-gravimetric ethembisayo kunye nophuculo olubalulekileyo kubomi besekethe, ii-anode ze-Si ezininzi ezibonisiweyo kude kube ngoku zigxile kakhulu kumthamo we-gravimetric kodwa azizange zinike ithemba elifanayo kumthamo wazo wevolumetric ngenxa yokuba uyilo lwe-electrode olukhoyo lusebenzisa isithuba esingagqibekanga ukuthatha indawo yokwanda kwevolumu ye-Si. Kwiindawo ezininzi ze-LIB kubandakanya izinto zombane eziphathwayo, nangona kunjalo, ididadi yamandla evolumetric iyinto ebalulekileyo ekuchongeni ukusebenza kwebhetri. Kufakwe kunye nobomi besekethe obonakalisiweyo, ubungakanani bamandla evolumetric obuphantsi bu ngoku bubugqirha obukhulu ekusebenziseni ii-anode ze-Si kutshone kutshona kwii-cells ezishishini. Ukudibana nale mvuzo ebalulekileyo, iteknoloji ye-anode ye-Si kufuneka iphinde ihlolwe kunye neeyunithi ezahlukeneyo ze-electrode ezinikezela ukusebenza okuzinzileyo kokujikeleza ngelixa ubungakanani be-electrode bukhutshelwe.  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 11 Nangona kukho iintlobo ezahlukeneyo ze-morphologies ze-Si kunye neekhompositi zazo kunye nezinye izinto eziqhuba ubutyebi, kulungelo eliqondakalayo lolungelo lokwenziwa kwezinto ezifuna ulawulo lomgangatho ophezulu, ukwenziwa okulula kunye nokukala kwezinto ze-Si ezisebenzayo kubalulekile. Ngokwembono yesicelo esisebenzayo, phakathi kwenani elikhulu labakhethiweyo abasebenzayo, ukusetyenziswa kwe-silicon nanoparticles (NPs) eshishini kunye nokugqoka komhlaba okusebenzayo nobuphumeleleyo kungalungela kakhulu. Izinto ezininzi eziqhuba ubutyebi kubandakanya i-carbon amorphous (AC) ziye zaphandwa njengezinto zokugqoka ii-anode ze-Si NP , , . Nangona kunjalo, uninzi lwazo alufikeleli ekwenzeni kakuhle okuzinzileyo kwexesha elide kuba izinto zokugqoka ezisetyenzisiweyo azikwazi ukuthatha indawo yokwanda kwevolumu ye-Si kwaye ngenxa yoko ziqhekeke kumjikelo wokuphinda.  8 20 21 Ngokuzama ukujongana nomda wezigqoko zangaphambili zokuqhuba ubutyebi kunye nokufumana ukwenziwa kakuhle kokujikeleza kunye nedidadi yamandla evolumetric ephuculweyo, kolu phando, sisebenzisa i-graphene ye-multilayer ekhule ngokuthe ngqo kumhlaba we-Si njengegqoko. Uhlobo olujonge phantsi (2D) lwe-graphene lunikezela ukusebenza okukhethekileyo kunye nobuphumeleleyo ii-anode ze-Si njengoko i-graphene ye-multilayer ingathatha indawo yokwanda kwevolumu ye-Si ngohlobo lokuhambelana phakathi kwemilawu elandelanayo ngaphandle kwesidingo sokubonelela ngesithuba esingagqibekanga   kwi-electrode eyenziweyo. Kwakhona, i-pellet ye-Si NP egqoke i-graphene ibonisa i-12.8 S cm−1 kwixabiso elincinci le-graphene ye-1 wt% ngomnxibelelwano oluchanekileyo lwe-percolation. Ngale njongo, sigqithise umngeni wokukhulisa i-graphene ngokuthe ngqo kumazwe e-Si ngaphandle kokwakheka kwe-Si carbide (SiC) ngokudala inkqubo yokuhambisa i-chemical vapour deposition (CVD) ebandakanya i-oxidant ethambileyo. Ukwakheka kwe-SiC kuyingozi kwii-anode ze-Si kuba i-SiC yi-insulator yombane eneziphene ezimbalwa. Ngaphezu koko, i-SiC ayisebenzi ekudibaneni kunye ne-Li ions kwaye ngenxa yoko ithintela ukuduma kwe-Li ion kwisigaba se-Si. Ngoncedo lwenkqubo yokuhambelana ye-graphene kunye nokuqhuba ubutyebi obuqinisiweyo, ii-Si NP zigqoke i-graphene zifikelela kumthamo wevolumetric we-2,500 mAh cm−3 (vs 550 mAh cm−3 ye-graphite eshishini), ixabiso eliphezulu phakathi kwezo zazisiweyo kude kube ngoku kuyo nayiphi na ii-anode ze-LIB ngelixa ibonisa ukujikeleza okubalulekileyo kunye nokusebenza kwereyithi.  phambi kwexesha Iziphumo Ukukhula kwe-graphene engenayo i-SiC phezu kwe-Si Ukukhula okuqondileyo kwe-graphene esemgangathweni ophezulu phezu kwe-Si nge-CVD process kubonise ubunzima  ngenxa yokuba iimeko eziqhelekileyo zokwenziwa kwe-graphene zifuna imeko yokunciphisa enokuthi isuse i-Si oxide layer yendalo kumhlaba we-Si, ize ithathe inxaxheba kwi-reaction phakathi kwe-Si kunye neziqhelo zekhabhoni ezidubulekayo ukuze zenze i-SiC . Indlela yethu yokuqala yokusebenzisa i-methane (CH4) njengesikhwelelo sekabhoni edibene ne-H2 ibelungelo lokungaphumeleli ukwenza i-graphene ikhule kwi-Si NPs ( ), ngaloo ndlela yenza i-β-SiC kuphela ( ). Ukugqitha kule mlinganiselo, sifake i-carbon dioxide (CO2), i-oxidant ethambileyo, kwi-CVD process kunye ne-CH4 ( , ). Ukufakwa kwe-CO2 kuvumela ukuba kuthintelwe ukwakheka kwe-SiC kunye nokunciphisa ubushushu bokukhula xa kuthelekiswa nokukhula kwe-graphene okwaziwayo kumhlaba . Kwingxelo yethu, kwi-900 °C, ukukhula kwe-graphene kwakungaphelelanga okanye kungalingani ( ), ngelixa ukukhula kwe-graphene kwi-1,100 °C kwavelisa imilawu ye-oxide kumhlaba we-Si eyayigqithile kakhulu ukuba kudume ubutyebi be-Li ion ( ). Kwiqondo lokushisa eliphakathi kwe-1,000 °C, i-2–10 imilawu ye-graphene yenze njengoko ibonisiwe kumifanekiso ye-electron microscope (TEM) ( ) ibonisa ngokucacileyo isakhiwo semilawu kunye nomgama ophakathi kwemilawu osondeleyo kwi-3.4 Å ( , i-inset). Ukujonga okusondeleyo kubonisa ukuba imilawu nganye i-anchored ngokuthe ngqo kumhlaba we-silicon particle eziceni zayo (iintolo ezibomvu kwi  ) kwaye ihambelane nomhlaba we-Si. Le milawu ye-graphene ehambelanisiweyo ingagcina isakhiwo sayo sokubeka imilawu nakude kube kuduma xa ikhona inkqubo yokuhambelana ( ), ngaloo ndlela ibonelela ngendlela ephilileyo yokuthatha indawo yokwanda kwevolumu ye-Si. Ukukhula kwe-graphene kuye kwazanywa kumazwe e-silicon dioxide (SiO2) kusetyenziswa i-CH4 kunye ne-H2 (refs  , ). Nangona kunjalo, ukukhula kwe-graphene kwezi nkqubo kwakukukhanuka okanye akuzange kuthintele ukwakheka kwe-SiC. Ukukhula okukhanukayo kucaciswa kwiindawo ezincinci zokukhuthaza kwi-SiO2 surface. Ngokungafaniyo, kwi-process yethu, ukongeza i-CO2 kuvelisa iindawo ezininzi zokukhuthaza ngohlobo lwe-SiOx kunye neziphene ezithile.  22 23 Supplementary Fig. 1 Supplementary Fig. 2 24 25 23 Supplementary Fig. 3 Supplementary Fig. 4 Fig. 1a,b Fig. 1b Fig. 1c Fig. 1d 26 27   ( ) Umfanekiso we-TEM ophantsi we-Gr–Si NP. ( ) Umfanekiso we-TEM ophezulu kwi-Gr–Si NP efanayo ukusuka kwibhokisi emhlophe kwi  . (Iinsets) Iiprofayili zomgca ukusuka kwiibhokisi ezimbini ezibomvu zibonisa ukuba umgama ophakathi kwemilawu ye-graphene yi ~3.4 Å, okungqinelanayo neyemilawu ye-graphene eqhelekileyo esekelwe kubudlelwane be-van der Waals. ( ) Umfanekiso we-TEM ophezulu obonisa imvelaphi (iintolo ezibomvu) apho imilawu ye-graphene enye ikhula khona. ( ) Umzobo oqala ukuchazwa ubonisa inkqubo yokuhambelana yezigqoko ze-graphene ezingqatyeni ezingakwazi ukugxotha ukwanda kwevolumu ye-Si.  a b a c d Ukukhula kwe-graphene engenayo i-SiC kuqinisekiswe zombini ukuhlalutya komthamo omkhulu kunye nokwama-particle angatshatanga. Iiprofayili ze-X-ray photoelectron spectroscopy kwi-Si 2  band ( ) kunye ne-X-ray diffraction (XRD) spectra ( ) azibonisi naziphi na iincopho ezihambelana ne-SiC kwi-graphene-coated Si (Gr–Si), AC-coated Si (AC–Si) kunye ne-Si yendalo, ngokungafaniyo nesampuli elawulayo (SiC–Si) eyenziwe ngendlela engenayo i-CO2 kusetyenziswa i-CH4 kunye ne-H2. Kwelinye icala, ukufota kwe-TEM okusebenzisa i-high-angle annular dark field kwabonisa ukuba i-Si NP inesakhiwo esiyingqimba-ngqimbana kunye ne-core ekhanyayo kunye ne-shell emnyama emaninzi ethi yingqimba ye-Si kunye ne-coating ye-oxide ( ). Ii-spectra ze-Electron energy loss spectroscopy (EELS) ( ) ezifunyenwe kumabala amaninzi kwi-NP azibonisi naziphi na iingcinga  ezibonisa ukwakheka kwe-SiC, ziqinisekisa ukukhula okungenayo i-SiC kwi-process yokukhula yangoku. Kwakhona, iingcinga ze-SiO2 kwi-108 eV zazifunyenwe kumabala 1 kunye 2 ngokomephu kunezinye iindawo embindini, nto leyo ibonisa ukuba umhlaba we-SiO2 usebenza njengeendawo zokukhuthaza ukukhula kwe-graphene. Ubukho obuqhubekayo bemilawu ye-SiO2 yaye buqinisekiswe yi-XRD ( ) kunye nokuhlalutya kwe-EELS ( ).  p Fig. 2a Supplementary Fig. 2 Fig. 2b Fig. 2c 28 Supplementary Fig. 2 Fig. 2b,c   ( ) Ii-spectra ze-X-ray photoelectron spectroscopy kwi-Si 2  band ye-Gr–Si, SiC–Si, AC–Si kunye ne-Si yendalo. ( ) Umfanekiso we-TEM osheshayo we-Gr–Si NP. ( ) Ii-spectra ze-EELS zamabala achaziweyo kwi  .  a p b c b Ukuhlalutya kwe-TEM  In situ Ngoku sijonga ukusetyenziswa kwe-Gr–Si njengegqoko le-anode kwi-LIBs. I-lithiation ye-Gr–Si NPs (1 wt% graphene) yajongwa ngexesha lokwenyani ngexesha lokwanda kwevolumu yayo kusetyenziswa ukuhlalutya kwe-TEM  , , , . Kwingxelo yokwenyani, ezinye ii-Gr–Si particles zabekwa kwii-electrode ezibotshwe nge-gold (Au). I-electrode yesibini, kodwa eyenziwa ihambele, ene-Li/LiO2 ekupheleni kwayo yafakwa ukuze iqhagamshelane nee-Gr–Si NPs ukuzidibanisa ( ). Xa iqhagamshelwaniswe ne-electrode yesibini, ii-particles zaqala ukukrala ( ). Iinkcukacha ezininzi malunga nale nkqubo zingabonwa kwi   kunye nee  . Iintlobo ezimbini zezakhiwo ezwandayo zabonwa, okukuthi ii-particles ezingena-ziphene kunye nee-particles ezineziphene njengoko ziboniswe kwi  . Kwiimeko apho i-graphene igubungela ngokupheleleyo iparticle kwaye ayinazo iziphene ezicacileyo ( ), ububanzi kwanda ngo ~30% (220% ukwanda kwevolumu). Ekupheleni kwe-lithiation, umgama ophakathi kwemilawu ye-graphene wandisa ukuya kwi-3.8 Å ibonisa i-Li intercalation , kwaye isakhiwo semilawu ye-graphene coating sagcinwa kwii-NP ezijikelezayo ( ), nto leyo ebonisa inkqubo yokuhambelana phakathi kwemilawu njengoko kuchaziwe kwi  . Kwiimeko apho kukho indawo eneziphene (bona isangqa esiluhlaza kwi  ), xa ikhula, iparticle engaphakathi iyaphuka kwaye iqhekeke ngesiphene ( ). Iimilo zeqhekeko ezibonwayo azinakwenzeka ukuba zivela kubungakanani beparticle, njengoko iparticle egubungelweyo enkulu kune-fractured particle kwi   ayizange yaphuka (bona ii-particles ezikhonjwe kwi-0 kunye ne-40 s kwi  ). Kwakhona, uqaphelo olutsha  lubonisa ukuba ukuba ayigubungelwanga, nkqu ii-particle ezincinci ze-Si (<50 nm) zingaphuka ngenxa yokuduma kwe-Li concentration gradient ngaphakathi kwii-particles ezingadala uxinzelelo olubalulekileyo. Ngapha koko, ubungakanani obubalulekileyo be-Si particle fracture bumxholo-mbali, kwaye buhambelana nendlela uxinzelelo olwakhiwe ngayo ngexesha lokwanda kwevolumu olukwazi ngayo ukukhutshwa. Ubungakanani obubalulekileyo bunganda kude kube yi->200 nm (ref.  ).  in situ 29 30 31 32 Fig. 3a Fig. 3b Supplementary Fig. 5 Supplementary Movies 1–3 Fig. 3b,c Fig. 3d 33 Fig. 3d Fig. 3c Fig. 3a Fig. 3e Fig. 3 Supplementary Fig. 5 34 35   ( ) Ii-Gr–Si NPs ezinamathiselwe kumhlaba we-Au wire kunye ne-electrode yesibini ye-Li/LiO2. ( ) Ezo Gr–Si NPs zangaphambili ziya kuduma. ( ) Isidima esiqala ukuchazwa sokuduma kwe-Gr–Si NPs zombini ingengena-ziphene kunye negubungelweyo eneziphene. ( , ) Imifanekiso ye-TEM esondeleyo ye- ( ) ingena-ziphene particle (leyo ijikelezwe ngomgca obomvu kwi   kunye ne  ) kunye ( ) iparticle eneziphene (leyo ijikelezwe ngomgca oluhlaza okwesibhakabhaka kwi   kunye ne  ). Ii-spectra ze-EELS kuzo zombini iimeko ziqinisekisa i-lithiation. Iiprofayili zomgca ukusuka kwiibhokisi ezibomvu kuzo zombini iimeko zibonisa ukwanda komgama ophakathi kwe-ca. 3.8 Å, ebonisa ukuduma kwindawo ephakathi kwe-graphene.  a b c d e d a b e a b Uhlalutyo lwe-EELS lwe-local ngexesha le-lithiation luqinisekisa i-lithiation ye-Si kuzo zombini iimeko ngokusebenzisa i-Li  -edge ekhaphazelekayo kufuphi ne-55 eV kunye ne-Si  -edge kwi-100 eV ( ; ref.  ). Umalawu oboniswe kumhlaba we-graphene kwi   uyathathwa njenge-Li/Li2O esele ikho. Ngokubanzi, imilawu ye-graphene igcina ukudityaniswa kunye ne-Si ngokusebenzisa iingcambu zayo ezibotshwe ngokweekhemikhali kumhlaba we-Si, kwaye ngelo xesha, inkqubo yokuhambelana ivumela i-graphene coating esemagqabini ukuba ithathe indawo yokwanda kwevolumu ye-Si. Kwingxelo ye-TEM   engahlukanga kunye ne-LIB electrode ye-Gr–Si, kwabonwa ukuba umndilili wenani leemilawu ye-graphene elingcatshiweyo kumaziko ahlukeneyo lincitshiswe ukusuka kwi-9.4 ukuya kwi-5.6 imilawu ( ) emva kwe-lithiation yokuqala, oku kuphinda kuqinisekise inkqubo yokuhambelana kwemilawu.  K L Fig. 3d,e 36 Fig. 3d ex situ Supplementary Fig. 6 Ukuqokelelwa kwe-graphene kunye nenkqubo yokuhambelana kwemilawu yenza uxinzelelo lokukhiya olunceda ukugcina ingqamleko ye-Si particle ngexesha lokwanda kwevolumu. Nangona kunjalo, le nkqubo yokukhiya ayibonakali ichaphaza i-Li diffusion, njengoko kufumaneka umthamo omkhulu weentlawulo kumlinganiso wokuchonga ombane. Kuyaphawuleka kwakhona ukuba ukwanda kwevolumu kwee-particles kube, ngokubanzi, kumalungu afanayo kuzo zonke iindlela zoradiyo nangona i-contact point kunye ne-electrode yesibini ijolise kakh

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