Nickel-cobalt-manganese ternary abu yana ɗaya daga cikin manyan kayan baturin wutar lantarki na yanzu. Abubuwa guda uku suna da ma’anoni daban-daban don kayan cathode, daga cikinsu akwai sinadarin nickel don inganta ƙarfin baturi. Mafi girman abun ciki na nickel, mafi girman ƙarfin takamaiman kayan aiki. NCM811 yana da takamaiman ƙarfin 200mAh/g da dandamalin fitarwa na kusan 3.8V, wanda za’a iya sanya shi ya zama babban baturi mai ƙarfi. Koyaya, matsalar baturin NCM811 rashin tsaro mara kyau ne da ruɓewar rayuwa cikin sauri. Menene dalilan da suka shafi rayuwar zagayowarta da amincinta? Yadda za a magance wannan matsala? Mai zuwa shine bincike mai zurfi:

An yi NCM811 ta zama baturin maɓalli (NCM811/Li) da baturin fakiti mai sassauƙa (NCM811/ graphite), kuma an gwada ƙarfin sa na gram da cikakken ƙarfin batir bi da bi. An raba baturin fakitin taushi zuwa ƙungiyoyi huɗu don gwaji guda ɗaya. Matsakaicin ma’aunin wutar lantarki ya yanke, wanda shine 4.1V, 4.2V, 4.3V da 4.4V, bi da bi. Na farko, an yi hawan batir sau biyu a 0.05c sannan kuma a 0.2C a 30 ℃. Bayan zagayowar 200, ana nuna lallausan madaurin zagayowar baturi a cikin hoton da ke ƙasa:

Ana iya gani daga wannan adadi cewa a ƙarƙashin yanayin babban ƙarfin wutan lantarki, ƙarfin gram na kwayoyin halitta da baturi duka suna da girma, amma ƙarfin gram na baturi da kayan kuma suma suna lalacewa da sauri. Akasin haka, a ƙananan ƙananan ƙarfin lantarki (kasa da 4.2V), ƙarfin baturi yana raguwa sannu a hankali kuma rayuwar sake zagayowar ya fi tsayi.

A cikin wannan gwaji, an yi nazarin halayen parasitic ta hanyar calorimetry na isothermal da kuma tsarin da lalata kwayoyin halitta na kayan cathode a lokacin hawan keke an yi nazarin XRD da SEM. Ƙarshen sune kamar haka:

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Na farko, canjin tsari ba shine babban dalilin raguwar rayuwar batir ba

Sakamakon XRD da SEM sun nuna cewa babu wani bambanci a fili a cikin kwayoyin halittar kwayoyin halitta da tsarin atomic na baturi tare da lantarki da yanke-kashe ƙarfin lantarki na 4.1V, 4.2V, 4.3V da 4.4V bayan 200 hawan keke a 0.2c. Don haka, saurin canjin tsarin abubuwa masu rai yayin caji da fitarwa ba shine babban dalilin raguwar rayuwar batir ba. Madadin haka, halayen parasitic a cikin mu’amala tsakanin electrolyte da ɓangarorin abubuwan da ke da ƙarfi sosai a cikin jihar delithium sune babban abin da ke haifar da rage rayuwar batir a babban yanayin ƙarfin lantarki na 4.2V.

(1) SEM

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A1 da A2 su ne hotunan SEM na baturin ba tare da kewayawa ba. B ~ E sune hotunan SEM na ingantaccen kayan rayuwa na lantarki bayan 200cycle ƙarƙashin yanayin 0.5C da cajin yanke-kashe ƙarfin lantarki na 4.1V/4.2V/4.3V/4.4V, bi da bi. Gefen hagu hoton microscope ne na lantarki a ƙarƙashin ƙarancin haɓakawa kuma gefen dama shine hoton microscope na lantarki ƙarƙashin babban haɓakawa. Kamar yadda ake iya gani daga hoton da ke sama, babu wani gagarumin bambanci a cikin ilimin halittar ɗan adam da matakin karyewa tsakanin baturi mai yawo da baturin da ba ya kewayawa.

(2) Hotunan XRD

Kamar yadda ake iya gani daga adadi na sama, babu wani bambanci a fili tsakanin kololuwa biyar a siffar da matsayi.

(3) Canja sigogin lattice

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Kamar yadda ake iya gani daga tebur, abubuwan da ke gaba:

1. Ƙaƙƙarfan lattice na faranti na polar da ba a yi amfani da su ba sun yi daidai da na NCM811 live foda. Lokacin da sake zagayowar yanke wutar lantarki ne 4.1V, da lattice akai ba shi da muhimmanci da bambanci daga baya biyu, da kuma C axis yana ƙaruwa kadan. Matsakaicin madaidaicin madaidaicin C-axis tare da 4.2V, 4.3V da 4.4V ba su da bambanci sosai da na 4.1V (0.004 angms), yayin da bayanan akan A-axis sun bambanta sosai.

2. Babu wani canji mai mahimmanci a cikin Ni a cikin ƙungiyoyi biyar.

3. Polar faranti tare da wutar lantarki mai kewayawa na 4.1V a 44.5 ° suna nuna babban FWHM, yayin da sauran ƙungiyoyin sarrafawa suna nuna irin wannan FWHM.

A cikin tsarin caji da cajin baturi, C axis yana da babban raguwa da faɗaɗawa. Rage rayuwar sake zagayowar baturi a babban ƙarfin lantarki baya saboda canje-canjen tsarin kwayoyin halitta. Don haka, abubuwan nan uku na sama sun tabbatar da cewa canjin tsarin ba shine babban dalilin raguwar rayuwar batir ba.

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Na biyu, rayuwar sake zagayowar batirin NCM811 yana da alaƙa da halayen parasitic a cikin baturin

NCM811 da graphite an yi su cikin sel fakiti masu sassauƙa ta amfani da electrolytes daban-daban. Sabanin haka, 2% VC da PES211 an ƙara su zuwa electrolyte na ƙungiyoyin biyu, bi da bi, kuma ƙarfin ƙarfin ƙarfin ƙungiyoyin biyu ya nuna babban bambanci bayan sake zagayowar baturi.

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Dangane da adadi da ke sama, lokacin da yanke-kashe ƙarfin lantarki na baturi tare da 2% VC shine 4.1V, 4.2V, 4.3V da 4.4V, ƙimar kiyaye ƙarfin baturi bayan zagayowar 70 shine 98%, 98%, 91 % da 88%, bi da bi. Bayan hawan keke na 40 kawai, ƙimar kiyaye ƙarfin baturi tare da ƙara PES211 ya ragu zuwa 91%, 82%, 82%, 74%. Mahimmanci, a cikin gwaje-gwajen da suka gabata, rayuwar sake zagayowar baturi na NCM424/ graphite da tsarin NCM111/ graphite tare da PES211 ya fi wannan tare da 2% VC. Wannan yana haifar da zato cewa abubuwan da ake amfani da su na electrolyte suna da tasiri mai mahimmanci akan rayuwar batir a cikin tsarin nickel mai girma.

Hakanan za’a iya gani daga bayanan da ke sama cewa zagayowar rayuwa a ƙarƙashin babban ƙarfin lantarki ya fi muni fiye da na ƙarancin wutar lantarki. Ta hanyar dacewa da aikin polarization, △V da lokutan sake zagayowar, ana iya samun adadi mai zuwa:

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Ana iya ganin cewa baturin △V yana da karami yayin hawan keke da karancin wutar lantarki, amma idan karfin ya tashi sama da 4.3V, △V yana karuwa sosai sannan kuma karfin baturi ya karu, wanda ke matukar shafar rayuwar batir. Hakanan za’a iya gani daga wannan adadi cewa canjin △V na VC da PES211 sun bambanta, wanda ya kara tabbatar da cewa digiri da saurin batir polarization sun bambanta da nau’ikan abubuwan da suka hada da electrolyte daban-daban.

An yi amfani da microcalorimetry na Isothermal don tantance yuwuwar amsawar batir. An fitar da ma’auni kamar polarization, entropy da kwararar zafi na parasitic don yin alaƙar aiki tare da rSOC, kamar yadda aka nuna a cikin hoton da ke ƙasa:

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Sama da 4.2V, ana nuna magudanar zafi na parasitic yana ƙaruwa ba zato ba tsammani, saboda ɗigon delithium anode surface yana amsawa cikin sauƙi tare da electrolyte a babban ƙarfin lantarki. Wannan kuma yana bayyana dalilin da yasa mafi girman cajin da fitarwar wutar lantarki, saurin kiyaye batirin yana raguwa.

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Iii NCM811 yana da rashin tsaro

A ƙarƙashin yanayin ƙara yawan zafin jiki, aikin amsawar NCM811 a cikin cajin jihar tare da electrolyte ya fi na NCM111 girma. Saboda haka, yin amfani da NCM811 samar da baturi yana da wahala a wuce takardar shaidar dole ta ƙasa.

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Adadin shine jadawali na ƙimar dumama kai na NCM811 da NCM111 tsakanin 70 ℃ da 350 ℃. Adadin ya nuna cewa NCM811 ya fara zafi a kusan 105 ℃, yayin da NCM111 ba ya zuwa 200 ℃. A NCM811 yana da dumama kudi na 1 ℃ / min daga 200 ℃, yayin da NCM111 yana da dumama kudi na 0.05 ℃ / min, wanda ke nufin cewa NCM811 / graphite tsarin da wuya a samu tilas aminci takardar shaida.

Babban abu mai rai na nickel tabbas shine babban abu na babban ƙarfin ƙarfin baturi a nan gaba. Yadda za a magance matsalar saurin ruɓewar rayuwar batir NCM811? Na farko, an gyara barbashi na NCM811 don inganta aikin sa. Na biyu shi ne amfani da electrolyte wanda zai iya rage karfin halayen biyun, ta yadda za a inganta rayuwarta da lafiyarta. Hoton

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