I-Nickel-cobalt-manganese ternary imathiriyeli yenye yezinto eziphambili zebhetri yamandla yangoku. Izinto ezintathu zineentsingiselo ezahlukeneyo zezinto ze-cathode, phakathi kwazo i-nickel element kukuphucula umthamo webhetri. Okuphezulu umxholo we-nickel, uphezulu umthamo wezinto eziphathekayo. I-NCM811 inomthamo othile we-200mAh / g kunye neqonga lokukhutshwa malunga ne-3.8V, enokuthi yenziwe ibe yibhetri ephezulu yamandla. Nangona kunjalo, ingxaki yebhetri ye-NCM811 lukhuseleko olubi kunye nokubola kobomi bomjikelo okhawulezayo. Ziziphi izizathu ezichaphazela ubomi bomjikelo kunye nokhuseleko? Indlela yokusombulula le ngxaki? Oku kulandelayo luhlalutyo olunzulu:

I-NCM811 yenziwe ibhetri yeqhosha (NCM811 / Li) kunye nebhetri yepakethe eguquguqukayo (NCM811 / graphite), kunye nomthamo wayo wegram kunye nomthamo opheleleyo webhetri wavavanywa ngokulandelelana. I-soft-pack yebhetri yohlulwe yangamaqela amane okulinga into enye. I-parameter variable yayiyi-voltage ye-cut-off, eyayiyi-4.1V, 4.2V, 4.3V kunye ne-4.4V, ngokulandelanayo. Okokuqala, ibhetri yayijikelezwe kabini kwi-0.05c kwaye emva koko kwi-0.2C kwi-30 ℃. Emva kwemijikelo engama-200, ipakethe ethambileyo yomjikelo wejiko iboniswe kumzobo ongezantsi:

Inokubonwa kumzobo ukuba phantsi kwemeko yombane ophezulu wokunqunyulwa, umthamo wegram yezinto eziphilayo kunye nebhetri zombini ziphezulu, kodwa umthamo wegram yebhetri kunye nezinto eziphathekayo nazo zibola ngokukhawuleza. Ngokuchasene noko, kwii-voltages ezisezantsi ezisikiweyo (ngaphantsi kwe-4.2V), umthamo webhetri uhla kancinci kwaye ubomi bomjikelezo bude.

Kolu vavanyo, i-reaction ye-parasitic yafundwa yi-calorimetry ye-isothermal kunye nesakhiwo kunye nokuthotywa kwe-morphology yezinto ze-cathode ngexesha lenkqubo yokuhamba ngebhayisikili zafundwa yi-XRD kunye ne-SEM. Izigqibo zezi zilandelayo:

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Okokuqala, utshintsho lwesakhiwo aluyena nobangela uphambili wokuhla kobomi bebhetri

Iziphumo ze-XRD kunye ne-SEM zibonise ukuba akukho mmahluko ocacileyo kwi-particle morphology kunye nesakhiwo se-athomu yebhetri ene-electrode kunye ne-cut-off voltage ye-4.1V, 4.2V, 4.3V kunye ne-4.4V emva kwemijikelezo ye-200 kwi-0.2c. Ke ngoko, utshintsho olukhawulezayo lwesakhiwo sezinto eziphilayo ngexesha lokutshaja kunye nokukhupha ayisosizathu siphambili sokuncipha kobomi bomjikelo webhetri. Endaweni yoko, ukusabela kwe-parasitic kujongano phakathi kwe-electrolyte kunye namasuntswana asebenza kakhulu ezinto eziphilayo kwimeko ye-delithium ngoyena nobangela wokuncipha kobomi bebhetri kumjikelo wombane ophezulu we-4.2V.

(1) i-SEM

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I-A1 kunye ne-A2 yimifanekiso ye-SEM yebhetri ngaphandle kokujikeleza. B ~ E yimifanekiso ye-SEM yezinto eziphilayo ze-electrode emva kwe-200cycle phantsi kwemeko ye-0.5C kunye nokutshaja i-voltage ye-cut-off ye-4.1V / 4.2V / 4.3V / 4.4V, ngokulandelanayo. Icala lasekhohlo ngumfanekiso we-electron microscope phantsi kokwandiswa okuphantsi kwaye icala lasekunene ngumfanekiso we-electron microscope phantsi kokwandiswa okuphezulu. Njengoko kunokubonwa kulo mzobo ungasentla, akukho mahluko ubalulekileyo kwi-particle morphology kunye neqondo lokuphuka phakathi kwebhetri ejikelezayo kunye nebhetri engajikeleziyo.

(2) Imifanekiso ye-XRD

Njengoko kunokubonwa kulo mzobo ungasentla, akukho mahluko ucacileyo phakathi kweencopho ezintlanu zokumila nokuma.

(3) Ukutshintshwa kweeparamitha ze-lattice

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Njengoko kunokubonwa kwitheyibhile, la manqaku alandelayo:

1. I-lattice constants of uncycled polar plates ihambelana ne-NCM811 powder powder. Xa i-voltage cutoff yomjikelezo i-4.1V, i-lattice constant ayihlukanga kakhulu kwizinto ezimbini zangaphambili, kwaye i-C axis iyanda kancinane. I-lattice constants ye-C-axis ene-4.2V, 4.3V kunye ne-4.4V ayihlukanga kakhulu kwezo ze-4.1V (0.004 angms), ngelixa idatha kwi-A-axis yahluke kakhulu.

2. Akukho tshintsho lubalulekileyo kumxholo we-Ni kumaqela amahlanu.

3. Amacwecwe e-polar ane-voltage ejikelezayo ye-4.1V kwi-44.5 ° ibonisa i-FWHM enkulu, ngelixa amanye amaqela okulawula abonisa i-FWHM efanayo.

Kwinkqubo yokutshaja kunye nokukhupha ibhetri, i-C axis ine-shrinkage enkulu kunye nokwandiswa. Ukuncitshiswa kobomi bomjikelo webhetri kumandla ombane aphezulu akubangelwa kukutshintsha kwezinto eziphilayo. Ke ngoko, la manqaku mathathu angentla aqinisekisa ukuba utshintsho lwesakhiwo ayisosizathu siphambili sokuhla kobomi bebhetri.

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Okwesibini, ubomi bomjikelezo we-NCM811 ibhetri inxulumene ne-reaction ye-parasitic kwibhetri

I-NCM811 kunye negraphite zenziwe kwiiseli zepakethe eziguquguqukayo zisebenzisa i-electrolyte eyahlukeneyo. Ngokuchaseneyo, i-2% VC kunye ne-PES211 zongezwa kwi-electrolyte yamaqela amabini, ngokulandelelana, kwaye izinga lokugcinwa komthamo wamaqela amabini libonise umahluko omkhulu emva komjikelo webhetri.

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Ngokomfanekiso ongasentla, xa i-voltage enqunyiwe yebhetri ene-2% VC yi-4.1V, 4.2V, 4.3V kunye ne-4.4V, izinga lokugcinwa kwebhetri emva kwemijikelo engama-70 yi-98%, 98%, 91 I-% kunye ne-88%, ngokulandelelanayo. Emva kwemijikelo engama-40 kuphela, izinga lokugcinwa kwamandla ebhetri eyongeziweyo i-PES211 yehle ukuya kuma-91%, 82%, 82%, 74%. Okubalulekileyo, kwiimvavanyo zangaphambili, ubomi bomjikelezo webhetri ye-NCM424 / igraphite kunye ne-NCM111 / i-graphite systems kunye ne-PES211 yayingcono kunoko nge-2% VC. Oku kukhokelela ekucingeni ukuba izongezo ze-electrolyte zinempembelelo enkulu kubomi bebhetri kwiinkqubo eziphezulu ze-nickel.

Kwakhona kunokubonwa kule datha ingasentla ukuba ubomi bomjikelezo phantsi kwamandla ombane aphezulu bubi kakhulu kunobo buphantsi kombane ophantsi. Ngokusebenza ngokufanelekileyo kwepolarization, △V kunye namaxesha okujikela, eli nani lilandelayo linokufumaneka:

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Inokubonwa ukuba ibhetri △V incinci xa uhamba ngebhayisekile kumbane osikiweyo, kodwa xa amandla ombane enyuka ngaphezu kwe-4.3V, △V inyuka kakhulu kwaye i-polarization yebhetri iyanda, echaphazela kakhulu ubomi bebhetri. Inokubonwa nakumfanekiso ukuba △V umyinge wokutshintsha kwe-VC kunye ne-PES211 yahlukile, nto leyo eqinisekisa ngakumbi ukuba idigri kunye nesantya se-polarization yebhetri yahlukile ngezongezo ezahlukeneyo ze-electrolyte.

I-Isothermal microcalorimetry isetyenziselwe ukuhlalutya ukusabela kwe-parasitic okunokwenzeka kwebhetri. Iiparamitha ezifana ne-polarization, i-entropy kunye nokuhamba kobushushu be-parasitic zacatshulwa ukwenza ubudlelwane obusebenzayo kunye ne-rSOC, njengoko kubonisiwe kumzobo ongezantsi:

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Ngaphezulu kwe-4.2V, ukuhamba kobushushu beparasitiki kuboniswa ukonyuka ngequbuliso, kuba umphezulu we-delithium anode usabela ngokulula nge-electrolyte kumbane ophezulu. Oku kukwachaza ukuba kutheni iphezulu i-voltage yentlawulo kunye nokukhupha, ngokukhawuleza izinga lokugcinwa kwebhetri liyancipha.

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Iii. I-NCM811 inokhuseleko olulambathayo

Ngaphantsi kwemeko yokunyusa ubushushu be-ambient, umsebenzi wokuphendula we-NCM811 kwi-charge state nge-electrolyte mkhulu kakhulu kune-NCM111. Ngoko ke, ukusetyenziswa kwe-NCM811 yokuveliswa kwebhetri kunzima ukudlula isatifikethi esinyanzelekileyo sikazwelonke.

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Umzobo yigrafu yezinga lokuzifudumeza kwe-NCM811 kunye ne-NCM111 phakathi kwe-70 ℃ kunye ne-350 ℃. Umzobo ubonisa ukuba i-NCM811 iqala ukutshisa malunga ne-105 ℃, ngelixa i-NCM111 ingenayo i-200 ℃. I-NCM811 inomlinganiselo wokufudumeza we-1 ℃ / min ukusuka kwi-200 ℃, ngelixa i-NCM111 inomlinganiselo wokufudumeza we-0.05 ℃ / min, oku kuthetha ukuba inkqubo ye-NCM811 / i-graphite inzima ukufumana isatifikethi sokhuseleko esinyanzelekileyo.

Izinto eziphilayo ze-nickel eziphezulu zibophelelekile ukuba zibe yimathiriyeli ephambili yebhetri yoxinaniso lwamandla kwixesha elizayo. Indlela yokusombulula ingxaki yokubola ngokukhawuleza kobomi bebhetri ye-NCM811? Okokuqala, i-particle surface ye-NCM811 yatshintshwa ukuze iphucule ukusebenza kwayo. Okwesibini kukusebenzisa i-electrolyte enokunciphisa ukusabela kwe-parasitic kwezi zibini, ukuze kuphuculwe ubomi bomjikelezo kunye nokhuseleko. Umfanekiso

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