Cov nyhuv ntawm NMP Kev Cuam Tshuam Ntawm Kev Ua Haujlwm Ntawm LFP Roj Teeb - Xov Xwm Kev Lag Luam

Lithium hlau phosphate (LiFePO4)Cov khoom siv cathode electroderoj-raws li slurry feem ntau sivN-methylpyrrolidone (NMP), dimethyl sulfoxide thiab dimethylformamide ua cov kuab tshuaj, uas muaj teeb meem xws li hnyav hnyav rov qab, siv ntau thiab ib puag ncig muaj kuab paug. LiFePO4 zoo electrode cov ntaub ntawv dej-raws li slurry siv dej deionized raws li hnyav, uas yog ib puag ncig tus phooj ywg thiab tus nqi qis, tab sis cov ntaub ntawv dej-raws li zoo electrode muaj teeb meem xws li tsis yooj yim, tsis muaj zog adhesion ntawm cov khoom siv thiab cov khoom siv hluav taws xob tsis zoo. Hauv daim ntawv no, cov nplooj ntawv zoo electrode nrog cov nyiaj sib txawv NMP ntxiv tau npaj los kawm txog cov txiaj ntsig ntawm NMP ntawm kev ua tau zoo ntawm cov ntawv zoo electrode npaj nrogDej-raws li binder LA132.

Kev sim

Lub aqueous binder LA132, superconducting carbon dub, dej deionized thiab LiFePO4 tau npaj rau hauv slurry ntawm qhov sib piv loj ntawm 2.5: 2.5: 5 0: 40. Plaub feem ntawm slurry tau ntxiv nrog 0, 1%, 2% thiab 3% NMP, suav A, B, C thiab D. Calendering qhov zoo electrode. Kev ziab cov electrode zoo ntawm 100 degree hauv lub tshuab nqus tsev rau 24h kom tshem tawm cov dej thiab NMP, thiab cov electrode zoo nrog cov ntsiab lus ntawm 95% tau npaj. Txiav rau hauv 20mm txoj kab uas hla discs. Sib dhos CR2016 npib ntawm tes nrog lithium hlau ntawv tsis zoo electrode, 1 mol / LLiPF6 / (EC + DEC + DMC) (ntim piv 1: 1: 1) electrolyte, microporous polypropylene separator, nyob rau hauv qhuav argon gas ntim hnab looj tes.

Ua ntej, khoov cov nplooj ntawv A, B, C, thiab D electrode 180 degrees, thiab tom qab ntawd sim cov adhesion ntawm cov nplooj ntawv electrode ntawm lub tshuab ntsuas tensile. Tom qab ntawd, ua ib qho kev xeem toughness ntawm cov ntawv electrode ntawm lub toughness tester (cov diameters ntawm cov ncej rods yog 1, 2, 3, 4, 6, 8, thiab 10 mm, ntsig txog), thiab saib seb puas muaj cov kab nrib pleb ntawm qhov chaw. ntawm cov nplooj ntawv electrode tom qab winding. Lub roj teeb them thiab qhov ntsuas qhov ntsuas tam sim no yog 0.1C, thiab qhov ntsuas hluav taws xob yog 2.5 ~ 3.5V.

Cov txiaj ntsig thiab kev sib tham

Daim duab 1 yog daim duab ntsuas ntawm qhov adhesion ntawm LiFePO4 electrode ntawm 180 degree dabtsi yog khoov. Nws tuaj yeem pom los ntawm daim duab 1 tias qhov adhesion ntawm cov electrode yog qhov zoo dua vim qhov sib ntxiv ntawm NMP, thiab kev txhim kho ntawm adhesion ntawm electrode yog proportional rau tus nqi ntawm NMP ntxiv. Adhesion yog ib hom van der Waals quab yuam, nyob ntawm kev sib cuam tshuam ntawm cov molecules.

Figure 1 Relationship between adhesion and NMP addition

Thaum lub sij hawm tsim cov txheej txheem ntawm LiFePO4 electrode nplooj ntawv, cov nplooj ntawv electrode yuav inevitably tuaj rau hauv kev sib cuag nrog oxygen hauv huab cua. Thaum lub sij hawm cua sov txheej txheem, cov rhuab electrode nplooj reacts nrog oxygen los tsim acidic pab pawg neeg. Cov pab pawg acidic tsis muaj cov khoom siv hluav taws xob thiab yuav tsim cov khoom siv hluav taws xob tsis muaj zog nrog (-CN) hauv cov ntaub ntawv aqueous. Nws yuav hloov cov thixotropy ntawm slurry, txo fluidity, thiab ua rau slurry tsis sib xws. Tom qab ntxiv NMP, nws yuav neutralize cov acidic pawg ntawm cov nplooj ntawv electrode. Nws tuaj yeem txo qhov poob ntawm electrons nyob rau saum npoo ntawm cov nplooj ntawv electrode, tiv thaiv cov slurry los ntawm thixotropy, thiab ua rau kom cov adhesion ntawm cov binder thiab cov khoom tam sim no. Qhov zoo electrode slurry yog tusyees dispersed thiab fluidity yog txhim kho, yog li txhim kho tus nqi ntawm cov slurry thiab cov ntaub ntawv electrode. Yog li ntawd, qhov sib ntxiv ntawm electron-nplua nuj hnyav NMP tuaj yeem txhim kho kev ua haujlwm ntawm lub roj teeb.

Table 1 qhia cov txiaj ntsig ntawm qhov kev sim yooj yim ntawm plaub hom electrode nplooj ntawv. Saib daim duab 1, nws tuaj yeem pom tias cov kab nrib pleb tshwm sim thaum 6 hli txoj kab uas hla winding koob kuaj qhov zoo electrode A, thiab thaum lub 1 hli txoj kab uas hla winding koob raug kuaj, cov electrodes B ~ D tsis muaj cov kab nrib pleb. Nws tuaj yeem pom tias qhov kev hloov pauv tsis zoo tshaj plaws yog cov dej ntshiab-raws li zoo electrode daim ntawv, uas yog qhov ua rau tawg, tawg thiab tawg thaum npaj. Ntxiv NMP tuaj yeem txhim kho qhov hloov pauv ntawm daim ntawv electrode thiab nce kev siv tus nqi ntawm daim ntawv electrode. Cov latex particles nyob rau hauv LA132 binder yog muaj zog polar polymers nrog muaj zog intermolecular rog thiab tsis muaj peev xwm twisting, thiab daim ntawv electrode yog yooj yim tawg. Nrog rau qhov sib ntxiv ntawm NMP, txoj kab uas hla ntawm cov latex hais nyob rau hauv LA132 binder nce, kev sib tw muaj peev xwm nce, cov saw molecular rotation muaj peev xwm txo qis, thiab qhov yooj ntawm daim ntawv electrode yog txhim kho.

Table 1 Kev sib raug zoo ntawm electrode yooj thiab NMP ntxiv tus nqi
Tsis muaj.	D10	D8	D6	D4	D3	D2	D1
A	Tsis muaj	Yooj yim	Yooj yim	Yooj yim	Yooj yim	Yooj yim	Yooj yim
B	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj
C	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj
D	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj	Tsis muaj

Table 2 qhia cov txiaj ntsig ntawm electrochemical kev ua tau zoo ntawm daim ntawv electrode. Qhov tseem ceeb ntawm thawj qhov kev tso tawm tshwj xeeb muaj peev xwm, kev them nqi thiab kev ua haujlwm tawm, tawm qhov nruab nrab qhov hluav taws xob thiab qhov sib piv tsis tu ncua tam sim no yog qhov zoo ib yam. Qhov no qhia tau hais tias qhov sib ntxiv ntawm NMP tsis muaj kev cuam tshuam rau lub peev xwm tawm thiab nqi thiab tawm cov yam ntxwv ntawm cov khoom siv hluav taws xob zoo ntawm cov ntawv zoo electrode.

Table 2 Electrochemical zog ntawm cov electrode
Tsis muaj.	Thawj qhov tso tawm tshwj xeeb muaj peev xwm /(mAh·g-1)	Charge thiab tso tawm efficiency /%	Tshem tawm qhov nruab nrab voltage / V	Tus nqi tam sim no tsis tu ncua /%
A	157.0	97.90	3.384	99.3
B	157.1	98.10	3.386	99.4
C	156.9	98.00	3.385	99.4
D	157.0	97.90	3.385	99.3

Figure 2 Relationship between constant current ratio and NMP addition amount

Cov duab 2 txog 4 qhia txog kev sib raug zoo ntawm qhov sib piv tam sim no, tus nqi tso tawm tshwj xeeb, tawm qhov nruab nrab voltage thiab NMP ntxiv tus nqi ntawm plaub daim ntawv electrode.

Los ntawm daim duab 2, nws tuaj yeem pom tias nyob rau hauv tib qhov kev sim ntsuas, qhov kev them nyiaj tas li tam sim no ntawm plaub lub roj teeb yog tag nrho saum toj 98.2%. Los ntawm cov duab 3 thiab 4, nws tuaj yeem pom tias qhov tso tawm tshwj xeeb thiab qhov nruab nrab ntawm qhov hluav taws xob ntawm tib daim ntawv electrode txuas ntxiv mus nrog qhov nce ntawm qhov paug tawm.

Figure 3 Relationship between discharge specific capacity and NMP addition amount

Lub peev xwm tawm thiab qhov nruab nrab ntawm qhov hluav taws xob ntawm electrodes A thiab B yog qhov zoo ib yam ntawm cov nqi sib txawv. Raws li tus nqi paug nce, qhov nruab nrab qhov hluav taws xob thiab qhov muaj peev xwm tawm ntawm electrodes C thiab D maj mam nce. Nws tuaj yeem pom tau tias thaum NMP ntxiv ntawm qhov siab tsis tshaj 1%, tus nqi tso tawm ntawm lub roj teeb yuav tsis cuam tshuam. Thaum NMP ntxiv ntawm ntau tshaj 1%, NMP yuav cuam tshuam rau lub peev xwm tawm thiab qhov nruab nrab ntawm qhov zoo electrode.

Figure 4 Relationship between median voltage and NMP addition amount

Daim duab 5 qhia txog lub voj voog kev ua haujlwm nkhaus ntawm plaub hom roj teeb. Los ntawm kev soj ntsuam daim duab 5, nws tuaj yeem pom tau tias thaum pib ntawm kev them nqi thiab kev tawm mus, qhov muaj peev xwm lwj ntawm cov nplooj ntawv electrode A thiab electrode B yog qhov zoo sib xws, thiab qhov muaj peev xwm lwj ntawm cov nplooj ntawv electrode C thiab electrode nplooj ntawv D zoo ib yam. , thaum tus nqi lwj ntawm electrode nplooj C thiab electrode nplooj D yog loj dua. Raws li lub voj voog txuas ntxiv, kev lwj ntawm cov nplooj ntawv electrode A, C thiab D nrawm, thiab qhov lwj ntawm electrode nplooj B tseem tsis hloov pauv. Qhov kawg roj teeb muaj peev xwm tuav tus nqi yog electrode daim ntawv D＜C＜A＜B. Qhov no qhia tau hais tias thaum tus nqi ntawm NMP ntxiv yog tsawg dua 1%, nws yog qhov zoo los txhim kho lub voj voog cov yam ntxwv ntawm lub roj teeb, thiab thaum tus nqi ntawm NMP ntxiv ntau dua 1%, lub voj voog yam ntxwv ntawm lub roj teeb yuav raug cuam tshuam.

Figure 5 Cycle curves of batteries with different NMP addition amounts

Xaus

Lub adhesion ntawm daim ntawv zoo electrode tuaj yeem txhim kho los ntawm kev ntxiv NMP, thiab qhov adhesion maj mam nce nrog qhov nce ntawm NMP ntxiv. Tom qab ntxiv NMP, cov pab pawg acidic ntawm cov electrode yuav raug nruab nrab, uas tuaj yeem txo qhov poob ntawm cov hluav taws xob ntawm electrode nto, tiv thaiv cov slurry los ntawm thixotropy, ua kom cov adhesion ntawm cov ntawv khi thiab cov khoom siv tam sim no, ua rau cov electrode slurry zoo sib xws. , thiab txhim kho cov fluidity, yog li txhim kho kev siv cov slurry thiab electrode. Thaum tus nqi ntawm NMP ntxiv yog tsawg dua 1%, nws yuav tsis cuam tshuam rau tus nqi tso tawm ntawm lub roj teeb thiab tuaj yeem txhim kho cov yam ntxwv ntawm lub voj voog ntawm lub roj teeb. Txawm li cas los xij, thaum tus nqi ntawm NMP ntxiv ntau dua 1%, NMP yuav cuam tshuam rau lub peev xwm tawm thiab qhov nruab nrab ntawm qhov zoo electrode thiab txo cov yam ntxwv ntawm lub voj voog ntawm lub roj teeb.