I-Nickel-cobalt-manganese ternary material ingenye yezinto eziphambili zebhethri lamandla lamanje. Izakhi ezintathu zinezincazelo ezihlukene zezinto ze-cathode, phakathi kwazo isici se-nickel siwukuthuthukisa umthamo webhethri. Ukuphakama kokuqukethwe kwe-nickel, kuyanda umthamo othize wezinto ezibonakalayo. I-NCM811 inomthamo othize we-200mAh/g kanye neplathifomu yokukhipha engaba ngu-3.8V, engenziwa ibe ibhethri elinamandla amakhulu. Kodwa-ke, inkinga yebhethri ye-NCM811 ukuphepha okungalungile kanye nokubola komjikelezo osheshayo. Yiziphi izizathu ezithinta impilo nokuphepha komjikelezo wayo? Indlela yokuxazulula le nkinga? Okulandelayo ukuhlaziya okujulile:

I-NCM811 yenziwe yaba yinkinobho yebhethri (NCM811/Li) kanye nebhethri lephakethe eliguquguqukayo (NCM811/ graphite), futhi umthamo wayo wegram nomthamo webhethri ogcwele wahlolwa ngokulandelana. Ibhethri le-soft-pack lihlukaniswe ngamaqembu amane okuhlolwa kwesici esisodwa. Ipharamitha eguquguqukayo bekuyi-voltage enqanyuliwe, eyayingu-4.1V, 4.2V, 4.3V kanye no-4.4V, ngokulandelana. Okokuqala, ibhethri lijikelezwe kabili ku-0.05c bese kuba ngu-0.2C ku-30℃. Ngemuva kwemijikelezo engu-200, ijika lomjikelezo webhethri lephekhi elithambile liboniswa esithombeni esingezansi:

Kungabonakala emfanekisweni ukuthi ngaphansi kwesimo se-voltage enqanyuliwe ephezulu, umthamo wegram wento ephilayo nebhethri kokubili kuphezulu, kodwa umthamo webhethri nezinto ezibonakalayo nazo ziwohloka ngokushesha. Ngokuphambene, kuma-voltage anqamuliwe aphansi (ngaphansi kuka-4.2V), umthamo webhethri wehla kancane futhi impilo yomjikelezo iba yinde.

Kulesi sivivinyo, ukusabela kwe-parasitic kwafundwa yi-calorimetry ye-isothermal kanye nesakhiwo kanye nokuwohloka kwe-morphology yezinto ze-cathode ngesikhathi senqubo yokuhamba ngebhayisikili kwafundwa yi-XRD ne-SEM. Iziphetho zimi kanje:

Isithombe

Okokuqala, ukuguqulwa kwesakhiwo akusona isizathu esiyinhloko sokwehla komjikelezo wempilo yebhethri

Imiphumela ye-XRD ne-SEM ibonise ukuthi wawungekho umehluko osobala ku-particle morphology kanye nesakhiwo se-athomu yebhethri ene-electrode kanye ne-cut-off voltage engu-4.1V, 4.2V, 4.3V kanye ne-4.4V ngemva kwemijikelezo engu-200 ku-0.2c. Ngakho-ke, ushintsho olusheshayo lwesakhiwo sento ephilayo ngesikhathi sokushaja nokukhipha akusona isizathu esiyinhloko sokwehla kwempilo yomjikelezo webhethri. Kunalokho, ukusabela kwe-parasitic kusixhumi esibonakalayo phakathi kwe-electrolyte nezinhlayiya ezisebenza kakhulu zento ephilayo esimweni se-delithium kuyimbangela eyinhloko yokuncipha kwempilo yebhethri kumjikelezo we-voltage ephezulu ongu-4.2V.

(1) i-SEM

Isithombe

Isithombe

I-A1 ne-A2 yizithombe ze-SEM zebhethri ngaphandle kokujikeleza. I-B ~ E yizithombe ze-SEM zezinto eziphilayo ze-electrode ngemva kuka-200cycle ngaphansi kwesimo esingu-0.5C kanye ne-voltage enqamuliwe yokushaja engu-4.1V/4.2V/4.3V/4.4V, ngokulandelana. Uhlangothi lwesobunxele yisithombe se-electron microscope ngaphansi kokukhuliswa okuphansi futhi uhlangothi lwesokudla isithombe se-electron microscope ngaphansi kokukhulisa okuphezulu. Njengoba kungabonakala esithombeni esingenhla, awukho umehluko obalulekile ku-particle morphology kanye nezinga lokuphuka phakathi kwebhethri elijikelezayo nebhethri elingazungezi.

(2) Izithombe ze-XRD

Njengoba kungase kubonakale emfanekisweni ongenhla, awukho umehluko osobala phakathi kweziqongo eziyisihlanu eziphakeme ngokuma nesikhundla.

(3) Ukushintsha kwemingcele ye-lattice

Isithombe

Njengoba kungabonakala etafuleni, amaphuzu alandelayo:

1. I-lattice constants yamapuleti e-polar angasetshenzisiwe ahambisana nalawo e-NCM811 powder ephilayo. Lapho i-voltage cutoff yomjikelezo ingu-4.1V, i-lattice engaguquki ayihlukanga kakhulu kwezimbili ezedlule, futhi i-axis ye-C ikhuphuka kancane. Ama-lattice constants e-C-axis ene-4.2V, 4.3V kanye ne-4.4V awahlukile kakhulu kulawo we-4.1V (0.004 angms), kuyilapho idatha eku-A-eksisi ihluke kakhulu.

2. Alukho ushintsho olubalulekile kokuqukethwe kwe-Ni emaqenjini amahlanu.

3. Amapuleti amhlophe ane-voltage ejikelezayo engu-4.1V ku-44.5° abonisa i-FWHM enkulu, kuyilapho amanye amaqembu okulawula ebonisa i-FWHM efanayo.

Enqubweni yokushaja nokukhipha ibhethri, i-axis ye-C inokushwabana okukhulu nokunwetshwa. Ukwehliswa kwempilo yomjikelezo webhethri kuma-voltage aphezulu akubangelwa izinguquko kusakhiwo sezinto eziphilayo. Ngakho-ke, amaphuzu amathathu angenhla aqinisekisa ukuthi ukuguqulwa kwesakhiwo akusona isizathu esiyinhloko sokwehla kwempilo yomjikelezo webhethri.

Isithombe

Okwesibili, impilo yomjikelezo webhethri ye-NCM811 ihlobene nokusabela kwe-parasitic ebhethri

I-NCM811 kanye ne-graphite kwenziwa amaseli ephakethe aguquguqukayo kusetshenziswa ama-electrolyte ahlukene. Ngokuphambene, i-2%VC ne-PES211 yengezwe ku-electrolyte yamaqembu amabili, ngokulandelana, futhi izinga lokugcinwa komthamo lamaqembu amabili libonise umehluko omkhulu ngemva komjikelezo webhethri.

Isithombe

Ngokusho kwesibalo esingenhla, lapho i-voltage enqanyuliwe yebhethri ene-2% VC ingu-4.1V, 4.2V, 4.3V kanye ne-4.4V, izinga lokugcinwa komthamo webhethri ngemva kwemijikelezo engu-70 ngu-98%, 98%, 91 % kanye nama-88%, ngokulandelana. Ngemuva kwemijikelezo engama-40 kuphela, izinga lokugcinwa komthamo webhethri ene-PES211 eyengeziwe lehle laya ku-91%, 82%, 82%, 74%. Okubalulekile, ekuhloleni kwangaphambilini, impilo yomjikelezo webhethri ye-NCM424/ graphite kanye nezinhlelo ze-NCM111/ graphite ene-PES211 yayingcono kunaleyo nge-2%VC. Lokhu kuholela ekucabangeni ukuthi izithasiselo ze-electrolyte zinomthelela omkhulu empilweni yebhethri kumasistimu e-nickel ephezulu.

Kungase futhi kubonakale kusukela kudatha engenhla ukuthi impilo yomjikelezo ngaphansi kwe-voltage ephezulu yimbi kakhulu kunaleyo engaphansi kwe-voltage ephansi. Ngokusebenza okufanelekile kwe-polarization, △V kanye nezikhathi zomjikelezo, isibalo esilandelayo singatholakala:

Isithombe

Kuyabonakala ukuthi ibhethri △V incane uma uhamba ngebhayisikili ku-voltage esike kancane, kodwa uma i-voltage iphakama ngaphezu kuka-4.3V, △V inyuka kakhulu futhi ukuhlukaniswa kwebhethri kuyanda, okuthinta kakhulu impilo yebhethri. Kungabonakala futhi esithombeni ukuthi izinga lokushintsha △V le-VC ne-PES211 lihlukile, okuqinisekisa futhi ukuthi idigri nesivinini sokuhlukaniswa kwebhethri kuhlukile ngezithasiselo ezihlukile ze-electrolyte.

I-Isothermal microcalorimetry yasetshenziswa ukuze kuhlaziywe amathuba okusabela kwe-parasitic ebhethri. Amapharamitha afana ne-polarization, i-entropy kanye nokugeleza kokushisa kwe-parasitic akhishiwe ukuze enze ubudlelwano obusebenzayo ne-rSOC, njengoba kuboniswe esithombeni esingezansi:

Isithombe

Ngaphezulu kuka-4.2V, ukugeleza kokushisa kwe-parasitic kuboniswa ukwanda kungazelelwe, ngoba indawo engaphezulu ye-delithium anode isabela kalula nge-electrolyte ku-voltage ephezulu. Lokhu kuphinde kuchaze ukuthi kungani ukuphakama kwe-voltage yokushaja nokukhipha, izinga lokugcinwa kwebhethri liyancipha ngokushesha.

Isithombe

Iii. I-NCM811 inokuvikeleka okubi

Ngaphansi kwesimo sokwandisa izinga lokushisa le-ambient, umsebenzi wokusabela we-NCM811 esimweni sokushaja nge-electrolyte mkhulu kakhulu kunalowo we-NCM111. Ngakho-ke, ukusetshenziswa kwe-NCM811 ukukhiqizwa kwebhethri kunzima ukudlulisa isitifiketi esiyimpoqo sikazwelonke.

Isithombe

Isibalo siyigrafu yamazinga okuzishisisa e-NCM811 kanye ne-NCM111 phakathi kuka-70 ℃ no-350℃. Isibalo sibonisa ukuthi i-NCM811 iqala ukushisa cishe ku-105 ℃, kuyilapho i-NCM111 ingafiki ku-200 ℃. I-NCM811 inezinga lokushisa elingu-1℃/min ukusuka ku-200℃, kuyilapho i-NCM111 inezinga lokushisa elingu-0.05℃/min, okusho ukuthi uhlelo lwe-NCM811/ graphite lunzima ukuthola isitifiketi sokuphepha esiyisibopho.

Izinto eziphilayo ze-nickel eziphezulu zizoba yizinto eziyinhloko zebhethri elinamandla amakhulu esikhathini esizayo. Ungayixazulula kanjani inkinga yokubola okusheshayo kwempilo yebhethri ye-NCM811? Okokuqala, i-particle surface ye-NCM811 yashintshwa ukuze kuthuthukiswe ukusebenza kwayo. Okwesibili ukusebenzisa i-electrolyte enganciphisa ukusabela kwe-parasitic kokubili, ukuze kuthuthukiswe impilo yomjikelezo wayo nokuphepha. Isithombe

Cindezela isikhathi eside ukuze uhlonze ikhodi ye-QR, engeza i-lithium π!

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