Zima akubwera, yang'anani pa otsika kutentha kusanthula chodabwitsa cha lithiamu-ion mabatire

Kuchita kwa mabatire a lithiamu-ion kumakhudzidwa kwambiri ndi mawonekedwe awo a kinetic. Chifukwa Li + imayenera kuwonongedwa poyamba ikayikidwa muzitsulo za graphite, imayenera kudya mphamvu inayake ndikulepheretsa kufalikira kwa Li + mu graphite. M'malo mwake, Li + ikatulutsidwa kuchokera ku zinthu za graphite kupita ku yankho, njira yothetsera vutoli idzachitika poyamba, ndipo njira yothetsera vutoli siifuna kugwiritsa ntchito mphamvu. Li + imatha kuchotsa graphite mwachangu, zomwe zimabweretsa kuvomereza kocheperako kwa zinthu za graphite. Mu kuvomereza kutulutsa .

Pa kutentha otsika, makhalidwe kinetic wa negative graphite elekitirodi bwino ndi kuipiraipira. Choncho, electrochemical polarization wa elekitirodi negative kwambiri kwambiri pa nawuza ndondomeko, amene mosavuta kuchititsa mpweya wa zitsulo lifiyamu pamwamba pa elekitirodi negative. Kafukufuku wa Christian von Lüders wa Technical University of Munich, Germany, wasonyeza kuti pa -2 ° C, mtengo wamtengo wapatali umaposa C / 2, ndipo kuchuluka kwa zitsulo za lithiamu mpweya kumawonjezeka kwambiri. Mwachitsanzo, pa C/2 mlingo, kuchuluka kwa lithiamu plating pa otsutsa elekitirodi pamwamba ndi za mlandu wonse. 5.5% ya mphamvu koma idzafika 9% pansi pa kukula kwa 1C. Lifiyamu yachitsulo yowonjezereka imatha kukula kwambiri ndipo pamapeto pake imakhala ma lithiamu dendrites, kuboola pa diaphragm ndikupangitsa kuti ma elekitirodi abwino ndi oipa azizungulira pang'ono. Choncho, m'pofunika kupewa kulipiritsa batire lithiamu-ion pa kutentha otsika mmene ndingathere. Pamene ayenera kulipira batire pa kutentha otsika, m'pofunika kusankha yaing'ono panopa kulipiritsa lifiyamu-ion batire mmene ndingathere ndi kusunga mokwanira lithiamu-ion batire pambuyo nawuza kuonetsetsa The zitsulo lithiamu precipitated kuchokera electrode negative. amatha kuchitapo kanthu ndi graphite ndikulowetsedwanso mu electrode yoyipa ya graphite.

Veronika Zinth ndi ena a Technical University of Munich anagwiritsa ntchito nyutroni diffraction ndi njira zina kuphunzira lifiyamu chisinthiko khalidwe la lithiamu-ion mabatire pa kutentha otsika -20 ° C . Neutron diffraction yakhala njira yatsopano yodziwira zaka zaposachedwa. Poyerekeza ndi XRD, diffraction ya nyutroni imakhudzidwa kwambiri ndi zinthu zowala (Li, O, N, etc.), kotero ndizoyenera kwambiri kuyesa kosawononga kwa mabatire a lithiamu-ion.

Poyesera, VeronikaZinth adagwiritsa ntchito batri ya NMC111 / graphite 18650 kuti aphunzire za kusintha kwa lithiamu-mabatire a lithiamu-ion pa kutentha kochepa. Batire imayimbidwa ndikutulutsidwa panthawi yoyesedwa molingana ndi ndondomeko yomwe ikuwonetsedwa mu chithunzi pansipa.

Chithunzi chotsatirachi chikuwonetsa kusintha kwa ma elekitirodi olakwika pansi pa ma SoC osiyanasiyana panthawi yolipiritsa yachiwiri pamtengo wa C/30. Zitha kuwoneka kuti pa 30.9% SoC, magawo a electrode negative ali makamaka LiC12, Li1-XC18, ndi pang'ono LiC6 Composition; SoC ikadutsa 46%, kuchulukira kwa LiC12 kumapitilirabe kuchepa, pomwe mphamvu ya LiC6 ikupitilira kukula. Komabe, ngakhale mtengo womaliza utatha, popeza 1503mAh yokha ndiyomwe imayimbidwa pa kutentha kochepa (kuchuluka kwake ndi 1950mAh kutentha kwa firiji), LiC12 ilipo mu electrode yolakwika. Tiyerekeze kuti ndalama zolipirira zatsitsidwa mpaka C/100. Zikatero, batire ikhoza kupezabe mphamvu ya 1950mAh pa kutentha kochepa, zomwe zimasonyeza kuti kuchepa kwa mphamvu ya mabatire a lithiamu-ion pa kutentha kochepa kumakhala makamaka chifukwa cha kuwonongeka kwa zinthu za kinetic.

Chithunzi chomwe chili pansipa chikuwonetsa kusintha kwa gawo la graphite mu elekitirodi yoyipa pakulipiritsa malinga ndi kuchuluka kwa C/5 pa kutentha kochepa kwa -20°C. Itha kuwona kuti kusintha kwa gawo la graphite ndikosiyana kwambiri poyerekeza ndi C / 30 mtengo wolipira. Zitha kuwoneka kuchokera pazithunzi kuti pamene SoC> 40%, mphamvu ya gawo la batri LiC12 pansi pa C/5 mtengo wamtengo wapatali imatsika pang'onopang'ono, ndipo kuwonjezeka kwa mphamvu ya gawo la LiC6 kumakhalanso kofooka kwambiri kuposa C/30. mtengo. Zikuwonetsa kuti pamlingo wokwera kwambiri wa C/5, kuchepera kwa LiC12 kumapitilira kuphatikizira lithiamu ndikusinthidwa kukhala LiC6.

Chithunzi chomwe chili pansipa chikufanizira kusintha kwa gawo la electrode yoyipa ya graphite pamene ikulipiritsa pa C / 30 ndi C / 5 mitengo, motero. Chiwerengerochi chikuwonetsa kuti pamitengo iwiri yolipiritsa yosiyana, gawo la lithiamu-osauka Li1-XC18 ndilofanana kwambiri. Kusiyanaku kumawonekera makamaka m'magawo awiri a LiC12 ndi LiC6. Zitha kuwoneka kuchokera pachithunzichi kuti kusintha kwa gawo mu electrode yolakwika kuli pafupi kwambiri ndi gawo loyamba la kulipiritsa pansi pamitengo iwiri yolipiritsa. Pa gawo la LiC12, mphamvu yolipiritsa ikafika 950mAh (49% SoC), kusintha kumayamba kuwoneka mosiyana. Zikafika 1100mAh (56.4% SoC), gawo la LiC12 pansi pa kukulitsa kuwiri limayamba kuwonetsa kusiyana kwakukulu. Mukamalipira pamtengo wochepa wa C / 30, kuchepa kwa siteji ya LiC12 kumathamanga kwambiri, koma kutsika kwa gawo la LiC12 pa mlingo wa C / 5 kumakhala pang'onopang'ono; ndiko kunena kuti, mikhalidwe ya kinetic ya kuyika kwa lithiamu mu electrode yoyipa imawonongeka pakutentha kochepa. , Kuti LiC12 ipitirirenso intercalates lithiamu kupanga LiC6 gawo liwiro utachepa. Momwemonso, gawo la LiC6 limakula mwachangu kwambiri pamlingo wotsika wa C/30 koma limachedwa kwambiri pamlingo wa C/5. Izi zikuwonetsa kuti pamlingo wa C / 5, Li wochulukira amayikidwa mumtundu wa kristalo wa graphite, koma chosangalatsa ndichakuti kuchuluka kwa batire (1520.5mAh) pamtengo wa C/5 ndikokwera kuposa ku C. / 30 mtengo wotsika. Mphamvu (1503.5mAh) ndiyokwera kwambiri. The owonjezera Li kuti si ophatikizidwa mu negative graphite elekitirodi n'kutheka kuti precipitated pa graphite pamwamba mu mawonekedwe a zitsulo lifiyamu. Kuyimirira pambuyo pa kutha kwa kulipiritsa kumatsimikiziranso izi kuchokera kumbali-pang'ono.

Chithunzi chotsatirachi chikuwonetsa mawonekedwe a gawo la electrode yoyipa ya graphite pambuyo polipira ndipo atasiyidwa kwa maola 20. Pamapeto pa kulipiritsa, gawo la elekitirodi yoyipa ya graphite ndi yosiyana kwambiri pamitengo iwiri yolipiritsa. Pa C/5, chiŵerengero cha LiC12 mu graphite anode ndichokwera, ndipo peresenti ya LiC6 ndi yotsika, koma atayima kwa maola 20, kusiyana pakati pa ziwirizi kwakhala kochepa.

Chithunzi chomwe chili pansipa chikuwonetsa kusintha kwa gawo la electrode yoyipa ya graphite panthawi ya 20h yosungirako. Zitha kuwona kuchokera pazithunzi kuti ngakhale magawo a ma electrode awiri otsutsana akadali osiyana kwambiri pachiyambi, pamene nthawi yosungiramo ikuwonjezeka, mitundu iwiri ya kulipiritsa Gawo la graphite anode pansi pa kukula kwasintha kwambiri. LiC12 ikhoza kupitiliza kusinthidwa kukhala LiC6 panthawi yashelving, kuwonetsa kuti Li ipitiliza kuyikidwa mu graphite panthawi yashelving. Mbali imeneyi ya Li mwina zitsulo lifiyamu precipitated pamwamba pa negative graphite elekitirodi pa kutentha otsika. Kusanthula kwina kunawonetsa kuti kumapeto kwa kulipiritsa pamlingo wa C/30, kuchuluka kwa lithiamu kuphatikizika kwa ma elekitirodi a graphite kunali 68%. Komabe, kuchuluka kwa kuphatikizika kwa lithiamu kunakwera mpaka 71% pambuyo pa shelving, kuwonjezeka kwa 3%. Pamapeto pa kulipiritsa pa mlingo C/5, lifiyamu kuyika digiri ya negative graphite elekitirodi anali 58%, koma atasiyidwa kwa maola 20, chinawonjezeka 70%, okwana kuwonjezeka 12%.

Kafukufuku pamwambapa akuwonetsa kuti polipira pazitentha zotsika, mphamvu ya batri imachepa chifukwa chakuwonongeka kwa ma kinetic. Komanso precipitate zitsulo lithiamu pamwamba pa elekitirodi zoipa chifukwa cha kuchepa kwa graphite lifiyamu kulowetsa mlingo. Komabe, patapita nthawi yosungirako, Mbali imeneyi ya zitsulo lifiyamu akhoza ophatikizidwa mu graphite kachiwiri; pakugwiritsa ntchito kwenikweni, nthawi ya alumali nthawi zambiri imakhala yochepa, ndipo palibe chitsimikizo kuti lifiyamu yonse yazitsulo imatha kuphatikizidwanso mu graphite, kotero kuti ikhoza kuchititsa kuti lifiyamu yachitsulo ipitirize kukhalapo mu electrode yolakwika. Pamwamba pa batire ya lithiamu-ion idzakhudza mphamvu ya batri ya lithiamu-ion ndipo ikhoza kupanga ma lithiamu dendrites omwe amaika pangozi chitetezo cha batri ya lithiamu-ion. Choncho, yesetsani kupewa kulipiritsa batire ya lithiamu-ion pa kutentha kochepa. Pakali pano, ndipo mutatha kukhazikitsa, onetsetsani kuti nthawi ya alumali yokwanira kuchotsa zitsulo za lithiamu mu electrode yolakwika ya graphite.

Nkhaniyi ikunena makamaka za zolemba zotsatirazi. Lipotili limangogwiritsidwa ntchito poyambitsa ndi kuwunikanso ntchito zokhudzana ndi sayansi, kuphunzitsa m'kalasi, ndi kafukufuku wasayansi. Osagwiritsa ntchito malonda. Ngati muli ndi vuto la kukopera, chonde khalani omasuka kutilankhula nafe.

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2.Lithium plating mu mabatire a lithiamu-ion amafufuzidwa ndi kupumula kwamagetsi ndi mu situ nyutroni diffraction,Journal of Power Sources 342(2017)17-23, Christian von Lüders, Veronika Zinth, Simon V.Erhard, Patrick J.Osswald, Michael Hofman , Ralph Gilles, Andreas Jossen

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