Mabatire a lithiamu-ion akukula kwambiri potengera kuchuluka kwamphamvu kwamphamvu. Pa kutentha kwa chipinda, silicon ofotokoza zoipa elekitirodi zipangizo aloyi ndi lifiyamu kutulutsa lithiamu wolemera mankhwala Li3.75Si gawo, ndi mphamvu yeniyeni mpaka 3572 mah/g, amene ali apamwamba kwambiri kuposa ongoyerekeza enieni mphamvu ya graphite zoipa elekitirodi 372 mAh/g. Komabe, panthawi yobwereketsa ndi kutulutsa mobwerezabwereza zipangizo za silicon-based negative electrode, kusintha kwa gawo la Si ndi Li3.75Si kungapangitse kuwonjezeka kwakukulu kwa voliyumu (pafupifupi 300%), zomwe zidzatsogolera ku ufa wopangidwa ndi electrode ndi kupangika kosalekeza kwa filimu ya SEI, ndipo pamapeto pake imapangitsa kuti mphamvu igwere mwachangu. Makampaniwa makamaka amawongolera magwiridwe antchito a zida za silicon-based negative electrode komanso kukhazikika kwa mabatire opangidwa ndi silicon kudzera mu nano-size, zokutira kaboni, mapangidwe a pore ndi matekinoloje ena.
Zida za kaboni zimakhala ndi ma conductivity abwino, otsika mtengo, komanso magwero ambiri. Iwo akhoza kusintha madutsidwe ndi kukhazikika pamwamba pa zipangizo silicon ofotokoza. Amagwiritsidwa ntchito makamaka ngati zowonjezera pakuwongolera magwiridwe antchito a ma electrode a silicon-based negative. Zida za silicon-carbon ndiye njira yayikulu yopangira ma elekitirodi a silicon-based negative. Kupaka kaboni kumatha kupititsa patsogolo kukhazikika kwazinthu zopangidwa ndi silicon, koma kuthekera kwake kuletsa kukula kwa voliyumu ya silicon ndikokwanira ndipo sikungathetse vuto la kukula kwa voliyumu ya silicon. Choncho, pofuna kupititsa patsogolo kukhazikika kwa zipangizo za silicon, ma porous amayenera kumangidwa. Mpira mphero ndi njira yopangira mafakitale pokonzekera nanomaterials. Zowonjezera zosiyanasiyana kapena zigawo zakuthupi zitha kuwonjezeredwa ku slurry yomwe imapezeka ndi mphero ya mpira molingana ndi zofunikira zamapangidwe azinthu zophatikizika. The slurry amamwazikana mofanana kudzera mu slurries zosiyanasiyana ndi kupopera-zouma. Pa nthawi yomweyo kuyanika ndondomeko, ndi nanoparticles ndi zigawo zina mu slurry adzakhala mowiriza kupanga porous structural makhalidwe. Pepalali limagwiritsa ntchito makina opangidwa ndi mafakitale komanso ochezeka ndi chilengedwe komanso mphero yopopera mankhwala kuti akonze zida za porous silicon.
Magwiridwe azinthu zopangidwa ndi silicon amathanso kuwongolera ndikuwongolera mawonekedwe a morphology ndi kugawa kwa silicon nanomaterials. Pakali pano, zipangizo silicon ofotokoza ndi morphologies zosiyanasiyana ndi makhalidwe kugawa zakonzedwa, monga pakachitsulo nanorods, porous graphite ophatikizidwa nanosilicon, nanosilicon anagawira mu carbon spheres, pakachitsulo / graphene gulu porous nyumba, etc. Pamlingo womwewo, poyerekeza ndi nanoparticles , ma nanosheets amatha kupondereza bwino vuto lophwanyidwa chifukwa cha kuchuluka kwa voliyumu, ndipo zinthuzo zimakhala ndi kachulukidwe kakang'ono kwambiri. Kusanjikiza kosasinthika kwa nanosheets kumathanso kupanga porous porous. Kuti mulowe nawo gulu la silicon negative electrode exchange. Perekani malo osungira kuti awonjezere voliyumu ya zida za silicon. The kumayambiriro mpweya nanotubes (CNTs) osati kusintha madutsidwe wa zinthu, komanso kulimbikitsa mapangidwe porous nyumba zakuthupi chifukwa cha mbali imodzi morphological makhalidwe. Palibe malipoti okhudza ma porous omangidwa ndi silicon nanosheets ndi CNTs. Pepalali limagwiritsa ntchito mphero yamagetsi, kugaya ndi kubalalitsidwa, kuyanika kutsitsi, kupaka kaboni chisanadze ndi njira calcination, ndipo imayambitsa olimbikitsa porous pokonzekera kukonzekera porous silicon ofotokoza zoipa elekitirodi zipangizo zopangidwa ndi kudzikonda msonkhano wa pakachitsulo nanosheets ndi Zithunzi za CNT. Njira yokonzekera ndi yophweka, yogwirizana ndi chilengedwe, ndipo palibe madzi otayika kapena zotsalira za zinyalala zomwe zimapangidwa. Pali malipoti ambiri okhudzana ndi zokutira za kaboni pazinthu zopangidwa ndi silicon, koma pali zokambirana zochepa zakuya kwakuya. Pepalali limagwiritsa ntchito phula ngati gwero la kaboni kuti lifufuze zotsatira za njira ziwiri zokutira mpweya wa kaboni, kuthira kwamadzimadzi ndi kuyika gawo lolimba, pazomwe zimapangidwira komanso magwiridwe antchito a silicon-based negative electrode materials.
1 Yesani
1.1 Kukonzekera kwazinthu
Kukonzekera kwa porous silicon-carbon kompositi zipangizo makamaka zikuphatikizapo masitepe asanu: mpira mphero, akupera ndi kubalalitsidwa, kupopera kuyanika, mpweya chisanadze ❖ kuyanika ndi carbonization. Choyamba, yezani 500 g ya silicon ufa woyambirira (wapakhomo, 99.99% chiyero), onjezani 2000 g wa isopropanol, ndikuchita mphero yonyowa pa mpira mphero liwiro la 2000 r/min kwa 24 h kuti mupeze nano-scale silicon slurry. The anapezedwa pakachitsulo slurry anasamutsidwa kwa thanki kutengerapo kumwazikana, ndi zipangizo anawonjezera malinga ndi misa chiŵerengero cha silicon: graphite (opangidwa ku Shanghai, batire kalasi): carbon nanotubes (opangidwa mu Tianjin, batire kalasi): polyvinyl pyrrolidone (opangidwa mu Tianjin, analytical grade) = 40:60:1.5:2. Isopropanol imagwiritsidwa ntchito kusintha zinthu zolimba, ndipo zolimba zimapangidwira 15%. Kugaya ndi kubalalitsidwa kumachitika pa kubalalika liwiro la 3500 r/mphindi kwa 4 h. Gulu lina la slurries popanda kuwonjezera CNTs likufananizidwa, ndipo zipangizo zina ndizofanana. Dothi lomwazikana lomwe limabalalitsidwa limasamutsidwa ku tanki yoyatsira utsi, ndipo kuyanika kumachitidwa mumlengalenga wotetezedwa ndi nayitrogeni, kutentha kolowera ndi kotuluka kumakhala 180 ndi 90 ° C, motsatana. Kenako mitundu iwiri ya zokutira za kaboni idafaniziridwa, zokutira gawo lolimba ndi zokutira zamadzimadzi. Njira yolimba yopangira gawo ndi: ufa wothira-owuma umasakanizidwa ndi 20% ufa wa asphalt (wopangidwa ku Korea, D50 ndi 5 μm), wosakanikirana ndi makina osakaniza kwa mphindi 10, ndipo liwiro losakaniza ndi 2000 r / min kuti mupeze. ufa wophimbidwa kale. Njira yokutira yamadzimadzi ndi: ufa wowumitsidwa umawonjezeredwa ku yankho la xylene (lopangidwa ku Tianjin, kalasi yowunikira) yomwe ili ndi 20% phula wosungunuka mu ufa pamalo olimba a 55%, ndi vacuum yogwedezeka mofanana. Kuphika mu uvuni wa vacuum pa 85 ℃ kwa 4h, kuyika mu chosakaniza chosakaniza kuti musakanize, kuthamanga kwa kusakaniza ndi 2000 r / min, ndipo nthawi yosakaniza ndi 10 min kuti mupeze ufa wophimbidwa kale. Potsirizira pake, ufa wophimbidwa kale unkawotchedwa mu ng'anjo yozungulira pansi pa mpweya wa nayitrogeni pa kutentha kwa 5 ° C / min. Poyamba idasungidwa pa kutentha kosalekeza kwa 550 ° C kwa 2h, kenako idapitilira kutentha mpaka 800 ° C ndikusungidwa kutentha kosalekeza kwa 2h, kenako idakhazikika mpaka pansi pa 100 ° C ndikutulutsidwa kuti ipeze kaboni-carbon. zinthu zophatikiza.
1.2 Njira zopangira zilembo
The tinthu kukula kugawa zinthu anali kusanthula ntchito tinthu kukula tester (Mastersizer 2000 Baibulo, anapanga ku UK). Ufa womwe umapezeka pagawo lililonse udayesedwa ndi kusanthula ma electron microscopy (Regulus8220, yopangidwa ku Japan) kuti awone mawonekedwe ndi kukula kwa ufa. Kapangidwe kagawo kazinthuzo kanawunikidwa pogwiritsa ntchito X-ray powder diffraction analyzer (D8 ADVANCE, yopangidwa ku Germany), ndipo kapangidwe kazinthuzo kanawunikidwa pogwiritsa ntchito chowunikira chamagetsi. Zomwe zidapangidwa ndi silicon-carbon composite zidagwiritsidwa ntchito popanga batani theka la cell ya CR2032, ndi kuchuluka kwa silicon-carbon: SP: CNT: CMC: SBR inali 92: 2: 2: 1.5: 2.5. The counter electrode ndi zitsulo lifiyamu pepala, electrolyte ndi malonda electrolyte (chitsanzo 1901, wopangidwa ku Korea), Celgard 2320 diaphragm ntchito, malipiro ndi kutulutsa voteji osiyanasiyana 0.005-1.5 V, mlandu ndi kutulutsa panopa ndi 0.1 C. (1C = 1A), ndipo kukhetsa kwamadzi ndi 0.05 C.
Kuti mupitirize kufufuza momwe zinthu zopangira silicon-carbon composite, batire laling'ono lofewa la 408595 linapangidwa. Elekitirodi zabwino amagwiritsa NCM811 (anapangidwa Hunan, batire kalasi), ndi negative elekitirodi graphite ndi doped ndi 8% pakachitsulo-carbon zakuthupi. The zabwino elekitirodi slurry chilinganizo ndi 96% NCM811, 1.2% polyvinylidene fluoride (PVDF), 2% conductive wothandizira SP, 0,8% CNT, ndi NMP ntchito ngati dispersant; The negative elekitirodi slurry chilinganizo ndi 96% gulu negative elekitirodi zakuthupi, 1.3% CMC, 1.5% SBR 1.2% CNT, ndi madzi ntchito ngati dispersant. Pambuyo oyambitsa, ❖ kuyanika, anagudubuza, kudula, lamination, kuwotcherera tabu, ma CD, kuphika, madzi jekeseni, mapangidwe ndi magawano mphamvu, 408595 laminated ang'onoang'ono zofewa mapaketi mabatire ndi mphamvu oveteredwa 3 Ah anakonzedwa. Kuchita kwa mlingo wa 0.2C, 0.5C, 1C, 2C ndi 3C ndi machitidwe ozungulira a 0.5C malipiro ndi kutulutsa kwa 1C adayesedwa. Charge ndi discharge voteji osiyanasiyana anali 2.8-4.2 V, mosalekeza pakali pano ndi mosalekeza voteji kulipiritsa, ndipo odulidwa panopa anali 0.5C.
2 Zotsatira ndi Zokambirana
Ufa woyamba wa silicon udawonedwa ndi scanning electron microscopy (SEM). The silicon ufa anali mosasinthasintha granular ndi tinthu kukula zosakwana 2μm, monga momwe chithunzi 1 (a). Pambuyo pa mphero ya mpira, kukula kwa ufa wa silicon kunachepetsedwa kwambiri mpaka pafupifupi 100 nm [Chithunzi 1 (b)]. Mayeso a kukula kwa tinthu adawonetsa kuti D50 ya ufa wa silicon pambuyo pa mphero ya mpira inali 110 nm ndipo D90 inali 175 nm. Kufufuza mosamala za morphology ya silicon ufa pambuyo pa mphero ya mpira kumawonetsa mawonekedwe osasunthika (mapangidwe a mawonekedwe osasunthika adzatsimikiziridwa mopitilira muyeso wa SEM pambuyo pake). Choncho, deta ya D90 yopezedwa kuchokera ku mayesero a kukula kwa tinthu iyenera kukhala kutalika kwa nanosheet. Kuphatikizidwa ndi zotsatira za SEM, zikhoza kuweruzidwa kuti kukula kwa nanosheet yomwe inapezedwa ndi yaying'ono kusiyana ndi mtengo wovuta wa 150 nm wa kusweka kwa silicon ufa panthawi yolipira ndi kutulutsa muyeso imodzi. Mapangidwe a morphology ofooketsa amakhala makamaka chifukwa cha mphamvu zosiyana zolekanitsa za ndege za crystalline silicon, zomwe {111} ndege ya silikoni imakhala ndi mphamvu yochepetsera kusiyana kuposa {100} ndi {110} ndege za crystal. Chifukwa chake, ndege ya kristalo iyi imachepetsedwa mosavuta ndi mphero ya mpira, ndipo pamapeto pake imapanga mawonekedwe osalala. Kapangidwe kameneka kamapangitsa kuti zinthu zikhale zotayirira, zimasunga malo oti silicon ichuluke, ndipo imapangitsa kuti zinthuzo zikhale zokhazikika.
The slurry munali nano-silicon, CNT ndi graphite anapopera, ndi ufa pamaso ndi pambuyo kupopera mbewu mankhwalawa anafufuzidwa ndi SEM. Zotsatira zikuwonetsedwa mu Chithunzi 2. Matrix a graphite omwe adawonjezeredwa asanapopedwe ndi mawonekedwe a flake omwe ali ndi kukula kwa 5 mpaka 20 μm [Chithunzi 2 (a)]. Mayeso ogawa tinthu tating'onoting'ono a graphite akuwonetsa kuti D50 ndi 15μm. Ufa wopezedwa pambuyo popopera mankhwala umakhala ndi mawonekedwe ozungulira [Chithunzi 2 (b)], ndipo zitha kuwoneka kuti graphite imakutidwa ndi wosanjikiza wokutira pambuyo popopera mbewu mankhwalawa. D50 ya ufa pambuyo kupopera mbewu mankhwalawa ndi 26.2 μm. Makhalidwe a morphological of the second particles adawonedwa ndi SEM, akuwonetsa mawonekedwe a porous yotayirira yomwe imasonkhanitsidwa ndi nanomaterials [Chithunzi 2 (c)]. Kapangidwe ka porous wapangidwa ndi pakachitsulo nanosheets ndi CNTs zopiringizana wina ndi mzake [Chithunzi 2(d)], ndi mayeso enieni m'dera (BET) ndi mkulu monga 53.3 m2/g. Choncho, pambuyo kupopera mbewu mankhwalawa, pakachitsulo nanosheets ndi CNTs kudzisonkhanitsa kupanga porous dongosolo.
Wosanjikiza wa porous adathandizidwa ndi zokutira zamadzimadzi, ndipo atawonjezera phula loyambira ndi carbonization, kuwunika kwa SEM kunachitika. Zotsatira zikuwonetsedwa mu Chithunzi 3. Pambuyo pa kaboni isanayambe, pamwamba pa particles yachiwiri imakhala yosalala, yokhala ndi chophimba chodziwikiratu, ndipo chophimbacho chimakhala chokwanira, monga momwe tawonetsera mu Zithunzi 3 (a) ndi (b). Pambuyo carbonization, pamwamba ❖ kuyanika wosanjikiza amakhala wabwino ❖ kuyanika boma [Chithunzi 3(c)]. Kuonjezera apo, chithunzi cha SEM chodutsamo chimasonyeza ma nanoparticles opangidwa ndi mzere [Chithunzi 3 (d)], chomwe chimagwirizana ndi makhalidwe a morphological a nanosheets, kutsimikiziranso mapangidwe a silicon nanosheets pambuyo pa mphero ya mpira. Kuphatikiza apo, Chithunzi 3 (d) chikuwonetsa kuti pali zodzaza pakati pa nanosheets. Izi makamaka chifukwa ntchito madzi gawo ❖ kuyanika njira. Yankho la asphalt lidzalowa muzinthuzo, kotero kuti pamwamba pa silicon nanosheets zamkati zimapeza chophimba choteteza kaboni. Choncho, pogwiritsa ntchito madzi gawo ❖ kuyanika, kuwonjezera kupeza yachiwiri tinthu ❖ kuyanika tingati, pawiri mpweya ❖ kuyanika zotsatira za pulayimale tinthu ❖ kuyanika akhoza analandira. Ufa wa carbonized unayesedwa ndi BET, ndipo zotsatira zake zinali 22.3 m2 / g.
Mpweya wopangidwa ndi carbonized unagwiritsidwa ntchito pofufuza mphamvu zowonongeka (EDS), ndipo zotsatira zikuwonetsedwa mu Chithunzi 4 (a). Pakatikati pa micron ndi gawo la C, lolingana ndi matrix a graphite, ndipo zokutira zakunja zimakhala ndi silicon ndi okosijeni. Kuti mupitirize kufufuza momwe silicon imapangidwira, kuyesa kwa X-ray diffraction (XRD) kunachitika, ndipo zotsatira zake zikuwonetsedwa mu Chithunzi 4 (b). Nkhaniyi imapangidwa makamaka ndi graphite ndi silikoni imodzi ya kristalo, yopanda mawonekedwe owoneka bwino a silicon oxide, zomwe zikuwonetsa kuti gawo la okosijeni pamayeso amagetsi amagetsi makamaka amachokera ku okosijeni wachilengedwe wa silicon pamwamba. Zinthu zopangidwa ndi silicon-carbon composite zimalembedwa kuti S1.
Zomwe zidakonzedwa za silicon-carbon ya S1 zidayikidwa pa batani-mtundu wa cell-cell ndikuyesa kutulutsa. Mphepete mwachitsulo choyamba chothamangitsira chikuwonetsedwa mu Chithunzi 5. Mphamvu yosinthika yeniyeni ndi 1000.8 mAh / g, ndipo kuyendetsa bwino kozungulira kumakhala kokwanira 93.9%, komwe kuli kopambana kuposa mphamvu yoyamba ya zipangizo zambiri za silicon popanda pre- lithiation inanena m'mabuku. Kuchita bwino kwambiri koyamba kukuwonetsa kuti zinthu zomwe zidapangidwa ndi silicon-carbon composite zimakhala ndi kukhazikika kwakukulu. Pofuna kutsimikizira zotsatira za porous dongosolo, conductive network ndi mpweya ❖ kuyanika pa kukhazikika kwa zipangizo pakachitsulo-carbon, mitundu iwiri ya silicon-carbon zipangizo zinakonzedwa popanda kuwonjezera CNT ndipo popanda choyambirira mpweya ❖ kuyanika.
The morphology ya ufa wa carbonized wa silicon-carbon composite material popanda kuwonjezera CNT ikuwonetsedwa mu Chithunzi 6. Pambuyo popaka madzi amadzimadzi ndi carbonization, chophimba chophimba chikhoza kuwoneka bwino pamwamba pa zigawo zachiwiri mu Chithunzi 6 (a). SEM yapakatikati ya zinthu zokhala ndi mpweya ikuwonetsedwa mu Chithunzi 6(b). Kuyika kwa silicon nanosheets kumakhala ndi porous, ndipo mayeso a BET ndi 16.6 m2 / g. Komabe, poyerekeza ndi mlandu wa CNT [monga momwe tawonetsera pa Chithunzi 3 (d), kuyesa kwa BET kwa ufa wake wa carbonized ndi 22.3 m2 / g], mkati mwa nano-silicon stacking kachulukidwe ndipamwamba, kusonyeza kuti kuwonjezera kwa CNT kungalimbikitse mapangidwe a porous dongosolo. Kuphatikiza apo, zinthuzi zilibe maukonde atatu-dimensional conductive network opangidwa ndi CNT. Zomwe zimapangidwa ndi silicon-carbon composite zimalembedwa kuti S2.
Makhalidwe a morphological a silicon-carbon composite material okonzedwa ndi olimba-phase carbon coating akuwonetsedwa mu Chithunzi 7. Pambuyo pa carbonization, pali chophimba chodziwikiratu pamwamba, monga momwe tawonetsera pa Chithunzi 7 (a). Chithunzi 7(b) chikuwonetsa kuti pali ma nanoparticles oboola pakati pamtanda, omwe amafanana ndi mawonekedwe a morphological a nanosheets. Kuchulukana kwa nanosheets kumapanga mawonekedwe a porous. Palibe chodzaza chodziwikiratu pamwamba pa ma nanosheets amkati, zomwe zikuwonetsa kuti chotchinga cholimba cha kaboni chimangopanga chophimba cha kaboni chokhala ndi porous, ndipo palibe nsanjika yamkati ya silicon nanosheets. Zinthu zopangidwa ndi silicon-carbon iyi zimalembedwa ngati S3.
Kuyesa kwamtundu wa batani la theka la cell ndi kutulutsa kunachitika pa S2 ndi S3. Mphamvu yeniyeni ndi mphamvu yoyamba ya S2 inali 1120.2 mAh / g ndi 84.8%, motero, ndi mphamvu yeniyeni ndi mphamvu yoyamba ya S3 inali 882.5 mAh / g ndi 82.9%, motero. Mphamvu yeniyeni ndi mphamvu yoyamba ya chitsanzo cholimba cha S3 chokhala ndi gawo lolimba chinali chotsika kwambiri, kusonyeza kuti chophimba cha carbon chopangidwa ndi porous chimapangidwa, ndipo kupaka mpweya wa silicon nanosheets wamkati sikunapangidwe, zomwe sizikanatha kusewera kwathunthu. ku mphamvu yeniyeni ya silicon-based material ndipo sakanatha kuteteza pamwamba pa silicon-based material. The dzuwa loyamba la chitsanzo S2 popanda CNT analinso m'munsi kuposa silicon-carbon gulu zinthu munali CNT, kusonyeza kuti pamaziko a wabwino ❖ kuyanika wosanjikiza, maukonde conductive ndi digiri apamwamba a porous dongosolo ndi abwino kwa kusintha. Kuwongolera ndi kutulutsa mphamvu kwa zinthu za silicon-carbon.
Zida za silicon-carbon ya S1 zidagwiritsidwa ntchito kupanga batire yaying'ono yofewa yodzaza ndi paketi kuti iwunikire momwe magwiridwe antchito amagwirira ntchito komanso kayendetsedwe kake. Mzere wokhotakhota ukuwonetsedwa mu Chithunzi 8 (a). Mphamvu zotulutsa za 0.2C, 0.5C, 1C, 2C ndi 3C ndi 2.970, 2.999, 2.920, 2.176 ndi 1.021 Ah, motsatira. Kutulutsa kwa 1C ndipamwamba kwambiri mpaka 98.3%, koma kutulutsa kwa 2C kumatsikira ku 73.3%, ndipo 3C kutulutsa kutsika kumatsika mpaka 34.4%. Kuti mulowe mgulu la silicon negative electrode exchange exchange group, chonde onjezerani WeChat: shimobang. Pankhani ya mtengo wolipiritsa, mphamvu zolipiritsa za 0.2C, 0.5C, 1C, 2C ndi 3C ndi 3.186, 3.182, 3.081, 2.686 ndi 2.289 Ah, motsatana. Mtengo wa 1C wolipiritsa ndi 96.7%, ndipo mtengo wa 2C umafikabe 84.3%. Komabe, poyang'ana pamapindikira opangira pa Chithunzi 8(b), nsanja yojambulira ya 2C ndiyokulirapo kuposa nsanja yojambulira ya 1C, ndipo kuchuluka kwake kwamagetsi kumawerengera ambiri (55%), zomwe zikuwonetsa kuti kuphatikizika kwa batire yowonjezereka ya 2C ndi. kale kwambiri. Zida za silicon-carbon zimakhala ndi kuyitanitsa komanso kutulutsa bwino pa 1C, koma mawonekedwe azinthuzo akuyenera kukonzedwanso kuti akwaniritse magwiridwe antchito apamwamba. Monga tawonetsera pa Chithunzi 9, pambuyo pa 450 cycle, mphamvu yosungira mphamvu ndi 78%, kusonyeza ntchito yabwino yozungulira.
Zomwe zili pamwamba pa electrode isanayambe komanso itatha kuzungulira kufufuzidwa ndi SEM, ndipo zotsatira zake zikuwonetsedwa mu Chithunzi 10. Asanayambe kuzungulira, pamwamba pa graphite ndi silicon-carbon zipangizo zimamveka bwino [Chithunzi 10 (a)]; pambuyo pa kuzungulira, ❖ kuyanika wosanjikiza mwachionekere kwaiye pamwamba [Chithunzi 10(b)], amene ndi wandiweyani SEI filimu. Kuvuta kwa filimu ya SEIKugwiritsa ntchito kwa lithiamu kumakhala kwakukulu, komwe sikuthandiza kuti mayendedwe azizungulira. Chifukwa chake, kulimbikitsa mapangidwe a filimu yosalala ya SEI (monga kupanga filimu ya SEI yochita kupanga, kuwonjezera zowonjezera zowonjezera ma electrolyte, ndi zina zotero) kungathe kupititsa patsogolo kayendetsedwe kake. The cross-Sectional SEM kuonerera kwa pakachitsulo-carbon particles pambuyo mkombero [Chithunzi 10(c)] limasonyeza kuti choyambirira Mzere woboola pakati pakachitsulo nanoparticles akhala coarser ndi kapangidwe porous wakhala kwenikweni inathetsedwa. Izi zimachitika makamaka chifukwa chakukula kwa voliyumu mosalekeza komanso kutsika kwa zinthu za silicon-carbon panthawi yozungulira. Chifukwa chake, mawonekedwe a porous akuyenera kukulitsidwanso kuti apereke malo okwanira kuti awonjezere kuchuluka kwazinthu zozikidwa pa silicon.
3 Mapeto
Kutengera kukula kwa voliyumu, kusasunthika kosasinthika komanso kusakhazikika kwa mawonekedwe a silicon-based negative electrode materials, pepalali limapanga zowongoka zomwe zikuyenda bwino, kuchokera ku mapangidwe a morphology a silicon nanosheets, mapangidwe a porous structure, conductive network yomanga ndi zokutira zonse za kaboni zagawo lonse lachiwiri. , kupititsa patsogolo kukhazikika kwa silicon-based negative electrode zipangizo zonse. Kuchuluka kwa silicon nanosheets kumatha kupanga porous porous. Kukhazikitsidwa kwa CNT kudzalimbikitsanso kupanga mapangidwe a porous. Zomwe zimapangidwa ndi silicon-carbon composite zokonzedwa ndi zokutira zamadzimadzi zimakhala ndi zokutira zapawiri za kaboni kuposa zomwe zimakonzedwa ndi zokutira zolimba, ndipo zimawonetsa mphamvu zapadera komanso kuchita bwino koyamba. Komanso, dzuwa loyamba la silicon-carbon gulu zinthu munali CNT ndi apamwamba kuposa kuti popanda CNT, amene makamaka chifukwa cha mlingo wapamwamba wa porous dongosolo mphamvu kuchepetsa voliyumu kukula kwa zipangizo pakachitsulo ofotokoza. Kukhazikitsidwa kwa CNT kudzapanga maukonde atatu-dimensional conductive network, kupititsa patsogolo kayendetsedwe kazinthu zopangidwa ndi silicon, ndikuwonetsa magwiridwe antchito abwino pa 1C; ndipo zakuthupi zikuwonetsa ntchito yabwino yozungulira. Komabe, mawonekedwe a porous a zinthuzo akuyenera kulimbikitsidwa kuti apereke malo okwanira kuti awonjezere kuchuluka kwa silicon, ndikulimbikitsa mapangidwe osalala.ndi kanema wandiweyani wa SEI kuti apititse patsogolo magwiridwe antchito a silicon-carbon composite material.
Timaperekanso zinthu zamtengo wapatali za graphite ndi silicon carbide, zomwe zimagwiritsidwa ntchito kwambiri pokonza zophatikizika ngati makutidwe ndi okosijeni, kufalikira, ndi kusungunula.
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Nthawi yotumiza: Nov-13-2024