Lan mooy mekaniismu reaction bu batëri? {2

Lan mooy mekaniismu reaction bu batëri?

Fi ñu tolli nii, amul benn xam-xam bu leer te méngoo ci anam wi ñuy doxalee ci wàllu electrochimique bu LiFePO₄ ci liggéey bi. Jëfandikoo anion composite (PO₄) 3 dafay defar iron- ay composé yu baax ci lithium {2}rioŋ batëri. Waaye, structure kristal bu LiFePO₄ dafay tënk yoon wi ak lithium- i liggéey, loolu moo jur wàññeeku ci performance electrochimique bi. Li wuute ak mbir yu am layer, charge-discharge ci LiMPO₄ dafay am plato bu plat lool, muy màndarga bu gëna fës ci ñaari {7{7}} ay reactions, loolu dafay tekki ni ab doxalinu fase diggante LiMPPO₄ ak MPO₄ dafay am ci biir lithium-on intercalation/detercalation.

LiFePO4 dafay dundu ñaari- ay mekanismu reaction reaction ci diiru sarse ak discharge ci batëri, maanaam

Reaction mechanism model

Bi ñuy sarse, Li⁺ dafay joge ci FeO₆ layer, dafay jaar ci electrolyte bi, ba noppi dugg ci electrode negatif bi. Fe2⁺ dañu koy oxide ci Fe3⁺, waaye electron yi dañuy jaar ci biir sircule bi ci biti dem ci electrode bu baaxul bi jaaraleko ci agent conducteur bi ak ñiy jël courant bi. Doxalinu decharge mooy retour bi.

Ngir leeral lii ñaar - sànn, Padhi ak Goodenough ak ñeneen. "core {-y xeetu", muy wax ni lithium-ion intercalation/detercalation dafay am ci LiFePO₄/FePO€ ñaari {4 }}phase, ni ñu ko wane ci Figure 4-3a.

Bu ñuy sarse, LiFePO₄/FePO₄ dafay wéy di joge ci kaw suuf si dem ci digg bi, di puus ci biir core bi. Li⁺ dafay wéy di dem ci biti, ba noppi LiFePOPO₄ dafay wéy di soppiku nekk FePO₄. Lithium ion ak electron dañuy wéy di jaar ci ñaari interfaasu {- sngural ngir mëna am courant bu am doole, waaye limu lithium-ion diffusion dafay wéy ci yenn anam. Bu diggante ñaari fase yi di wàññeeku, diffusion ion litium yi dina ñu mujjee doy ngir mëna wéy di am courant bu baax. LiFePO₄ ci core particule du ko jëfandikoo bu baax, te loolu mooy tax ñu ñàkk kàttan. Ginaaw sarse bi matna, LiFePOPO₄ du nekk ci diggu particule bi.

Bu ñu sukkandikoo ci ni ion litium yi mën nañu boole ay barab yu bari, Anderson et al. defar xeetu mosaic ngir leeral ñàkka mëna am kàttan, ni ñu ko wane ci nataal 4{3} 3b. Modèle mosaïk bi dafay wax ni, ak li lithium ion bi di boole ak deintercalation mingi ci LiFePOPO₄/FePO2€ ñaari {5 {5} } Ñépp, mën na am ci bépp barab bu nekk ci biir particule bi. Bi ñuy sarse, FePO₄ bi dafay yokk ci barab yu wuute ci particule yi, ak catu gox yooyu ci gox yooyu, loolu dafay jur ay zone yu dee yu amul njariñ, loolu mooy waral kàttan gi di ñàkk. Bu ñuy dindi, reaction bi ci ginaaw dafay am, ion litium ion yiy boole ci fase FePO₄. Wàll wi ci core bi ion litium ion yi duñu boole résultaa yi ci ñàkka am kàttan.

Figure 4-3 Lithium-ion intercalation/deintercalation model of lithium iron phosphate battery

Ñaari xeetu xam-xam lañu defar ci benn yoon, waaye core {0}y, gëstukat yi ñoo gëna nangu, waaye li gëna am solo ci xeetu mbir yi ak core bi dañuy wéy di jur coow. Buñu sukkandikoo ci ñaari xeetu mbir yooyu, mën nañu ni kinetik bi am ci ion litium yi ak charge yi ñooy waral jëfandikoo macceer electrode bi yépp. Ci waajal mbir yi am ci phosphate fer litium, dañu def ay jeego ngir am particule yu am particule yu ndaw te wuute (nanoscale wala microporous), jëfandikoo coating coating (film nanocarbon) ak doping ion ngir gëna mëna jëfandikoo ak diffusion ion litium.

Ak xam-xam bu gëna xóot ci mbir yu LiMPPO, ñu gis ni ñaari xeetu mbir yooyu dañu doon sàggane màndarga yi anisotropic bu am solo ci dem ak dikk ci ion lithium ci LiMPPO. Laffont dafa laaj "New Core {1}shell Modèle" ngir saafara jafe-jafe yi ci "core-y model." Buñu sukkandikoo ci lii, Delmas dafa jàngat particule LiFePO yi ci anam yu wuute, ba noppi ñu tànn "Domino {(4}} Model", loolu mooy leeral bu baax chargement bi ak defar particule nanoscale, ni ñu ko wane ci Figure 4-4.

Doonte wuute yu am solo yi am ci diggante model yiñ waxoon, jafe-jafe core mingi ci xam-xam ak fësal interface bi ñaari-phase. Bi kinetik ci lithium dugal / extraction ak coppite fase bi mingi aju bu baax ci dayo particule, morphologie, ak màndarga physicochimiques ci materiyel bi, waxtaan yi ñu wax ci kaw (bokk ci ay xeetu xeex) mën nañu ko aju ci anam yu doyul yu ñuy jàngat.

Ak defar microscopie ak spectroscopie, gis-gis yu am solo ak fase yu digg yi, ñu gis ko ci jamonoy coppite ci fase LiMP4, loolu dafay wane ni beneen anam bu jaar yoon mën na am ci LiMPef4. Ci reaction solution yu dëgër yi, parametru selil yi ak volume selul yi dañuy wane coppite yu wéy ci jamonoy coppite ci fase yi. Ci yenn anam yu bari ay test ak ay anam yu ñuy màndargaale, lu ci melni ultra {4}) particules (nanoscale) ak bu kawe {5} saròt {6 }dicharge (ci kaw 10C), reactions solution yu dëgër ak nekkinu fase yu digg yi ñu ngi ko seetlu ci LiMPO4.

Transitions fiche ci diiru sarse {- discharges ci tàngooru néeg. Lithium { 2 }oon batëri yi dañuy wane bu baax ci sarse {-dasarse, te loolu mingi aju ci ni ñuy nuru ci diggante etaa yi ginaaw lithium {4}on deintercalation/intercalation. Ci diiru sarse - discharge decascharge, kàttanu batëri bi dafa lëkkaloo bu baax ak kinetik transisioŋ bi. Sunu sukkandikoo ci structure LiFePO4, yoon wi [100] moo gëna baax ci lithium-on migraasioŋ, te interface bi am ci diggante ñaari fase yi dafay dem ci c{111}}axioŋ ci diiru charge {12} discharge.

(1) LiFePOñThe ratio of LiFePO₄/FePO₄ changes continuously with the battery charge-discharge reaction (the value of x in LiₓFePO₄ changes continuously). As lithium ions are extracted, the intensity of the diffraction peak produced by LiFePO₄ gradually decreases. When δ>0.2, diffraction bi ci Li ₁₁₁₴FePO₄ dafay tàmbali réer, te dooley peak bi ci diffraction bi FePO₄₄ di gëna yokk. Waaye, ginaaw bi ion litium yi duggee, dooley diffraction bi ñuy génne ci FePO₄ dafay wàññeeku ndànk, ak dooley peak diffraction bi Li…

(2) LiₓFePOPOB/Li₁6LiₓFePO2€ ci tàngooru néeg mooy njaxasu Fe3 ₺/Fe21⁄4‐Fe2⁺ jaxaso {0}) valence Li ₐFePO2€/LiBiP. ak representé densité porte bi ak probabilite hopping bi ci sarse ak discharge, ci ñoom ñaar. Diffraction neutron bi dafa wane ni valeur yi gëna baax ak 0.05 ak 0.11, ci ñoom ñaar. Facteur yu melni doping ion, tàngoor, metal, dayo particule, ak non-equilibrium ci ëpp doole yépp a ngi am njeexital ci valeur yi ak . Yokk valeur yi ak dina gëna yokk performance kinetik bi reaction electrode bi ci diiru sarse ak discharge ci tàngooru néeg.

Ci 450 degre, amna pexe bu am solo bu Li ₓFePO₄ am, waaye ci tàngooru néeg, ñaari fase metastable am nañu: Li₇₅ FePO2 ak Li€ ak Li€. Ci kaw 500 degre, Li ₓFePOPO₄ dafay tàmbali def ay composé yu amul {5} ; composition ak ëmbiitu phosphates wala phosphides a ngi aju ci valeur x. Diggante 400 ak 500 degre, li Li ₓFePO₄ am rek la am.

Coppite yi am ci sedd bi ñoo gëna bari ay jafe-jafe ak ñi ñuy tàngal. Li ñuy boole ci njaxas mi mingi aju ci valeur x bi ak ci termik bi. Bu ñu seddee, Li ₓFePO₄ dafay njëkka dem ba ci njaxasu ñaari fase yu amul-loviine, diggante bi mingi aju ci valeur bi njëkk ci tàngoor ak x. Su tàngoor wi nekkee ci suuf (140±20 degre), ñaari- system dafa nekk sistem bu gëna xawa jafe, ci la LiFePO₄ ak FePO₄ coexist ak ñaari oliveine {7} xeeti composé, Li ₓ€ ak Li€ May jaxase njaxas mi ci tàngooru néeg bi dafay tax sistem bu am ñeenti- dafay soppi ndànk-ndànk ci ñaari {10} system LiFePO₄ ak FePO₄.

Battery reaction mechanism

FePO₄ mingi am ci anam yu bari: ① Ginaaw ñu defaree LiFePO₄ bu mat sëkk, FePO₄, orthombic FePO₄. ‡ FePO₄ amna quartz {-, ak bépp tetrahedral buñ boole; ③ Monoclinic ak orthombic FePO₄ mën nañu ko waajal ci seen hydrats. Xeetu kristal yii yépp ci FePO₄, ak FePO₄ amorf, mën nañu ko soppi def ko FePO₄ bu gëna neex.

Coppite bi am ci LiFePO₄ ak FePO₄ dafay yeex, te matul, waaye matna su tàngoor wi weesu 500 degre. Ci anam wi batëri bi di doxee, macceer kat bi dafa dëgër. Ci biir synthese LiFePO₄, fàww ñu fexe ba FePO₄ amul. Sudee leegi, FePO₄ dina am ci tàngal, mu jur - fas wu amul-, fasu weer ci kaw macceer bi ci tàngoor wu metti.

Dopping ion mën na yokk doxalinu macceer yi. P{1} xeeti macceer yu semi-conducteurs yu am yoon ñuy yegg ci 10⁄0⁐S/cm ñu ngi koy am ci doping ion. Dopping anam wu jafee xam la: ci genn wet gi, xayma fonctionnel (DFT) ci structure elektronik bu LiFePOPO₄ ci suufu densité bu dëgër bi (LDA) ak xayma gradient général (GGA) dafay wane ni macceer bi dafa wara fësal màndarga yi ci benn macceer metal wala semi-conductor, ak bande valence bu tollu ci 0.3 eV, muy lu jaarul yoon gis. Ci beneen wàll bi, soo seet ni orbitaal electron yi ak jaxasoo Coulomb yi di jaxasoo ginaaw doping ion, xeetu bande valence bu gëna baax mën nañu ko am.

Xayma DFT yu Mg{- wala Cr{1}}du LiFePO₄ dafay wane ni densité bi gëna mag ci staas elektronik mingi nekk ci wetu niveau Fermi, biy leeral yoon wi ñuy jëfandikoo ci metal bi. Coppite ci doxalinu yoon wi doping ion mëna jur mën na nekk ci mbir yii:

1) Ci wetu gox yi ñuy sarse ay sarse dañu leen di metalise.

2) Ion doping dafay tënk yaatuwaayu bande valence bi ak bande conduction.

3).

4) Xeetu, concentration, ak séddale ion dopant yi.

5) Ci M{{1}O oxides metal, bande de conduction de fer dafay feeñ su M{ {2}MM distance distance bi di gëna néew 3 × 10⁠1

6) Ci synthese, yokk ci karbon organik dafay indi coating carbone ci macceer bi, loolu mooy tax ñu mëna jaar yoon.

7) Feebaru FeP. Ci jamonoy synthese, yokk karbon bu ëpp dafay wàññi phosphate bi.

Ion doping and conductivity

8) Fe3 ⁺/Fe2 ⁺ ñaari redox dafay nekk katalist ci wàññi LiFePO2₄.

LiFePO₄ dafay wane reactivité ak electrolytes yu bari. Doxalinu electrochimique bi ci materiel bi dafay méngoo bu baax ak chimie surface bi ci biir electrolyte bi. Daanaka filmu buy def passivation mingi aju ci kaw suuf si. Filmu bii dafay yombal lithium-ion diffusion, dafay tere macceer bu am doole, te dafa wara mëna dékku coppite ci volume ak surface ci diiru litium {4}on/extraction. Carbon- filme liFePO₄ filmu yi dañu am ay composé yu melni LiF, LiPF₆, Li ₓFᵧ⁄2, ak Li… Li…

Elektrolite yu bari yi dañuy faral di am carbonate ak xorom yu am litium. Materialu cathode bi dafay dundu lu bari ci electrolyte bi. Ci misaal, ci LiPF₆ solution, asid-base bi am ci diggante LiFePO₄ ak limu HF mënul moytu. nekkinu HF ci electrolyte amna ñaari njeexital yu bon: li ci njëkk mooy reaction bi am ci diggante ion fer ak proton; ak ñaareel ba, reaction ion Li ak F ions ci kaw particule yi ngir sos LiF, loolu dafay tere Li. diffusion.

ion uron yi dañuy seey ci electrolyte yi. Test yiñ def ci ion fer bi di tas LiFePO₄ ci electrolytes yu wuute yi dañu wane lii ci topp:

1) Ci electrolyte yi amul benn contaminant asid, ba ci tàngoor wu yéeg, dissolution ion fer ak ñàkka mëna am ci macceer bi am ci liggéey bi.

2) Asidité bu gëna kawe mooy tax ion fer gëna yomb.

3) Tàngoor wu gëna kawe mooy tax ion fer bi gëna yomb.

4) ëmbiitu karbon bu gëna kawe ci biir materiyel bi mooy gëna am doole ci macceer bi.

Barabu jokkolante bi am ci digganté macceer bi ak linder bi mooy gëna am solo ci corrosion. Korosion bi mën nañu ko moytu soo jëfandikoo mesophase alkaine wala nga jëfandikoo scavens yu asid. Ci lithium { 2} 10 batëri yu jëfandikoo LiFePO₄ ni materiyel cathode bi, amul-acidic electrolytes wala yokk karbon wala coating LiFePO₄ ngir moytu ñu ñàkk lu bari.

Màndarga kinetik yi ci LiFePO₄ ci kathode cathode, ba leegi xama guñu ko bu baax. Dañu gëm ni dayo partikil bi ak séddale bi, yoon, diffusion ion, kinetik ci diggante fase yi (comping-dicharge), ak coating / doping lépp a ngi indi jafe-jafe ci performance batëri bi ci yeneen charge {2} dicharge. Dopping karbon bu amul benn onde dafay tekki ni mën nañu dugal ion lithium ak electron yi ba noppi génne ko ci barab bi ci materiyel bi, wàññi polarisaasioŋ electrode bi.

(1) Njàngat ci Defeductivibility ci kàttan. LiFePOPO₄ mooy yoon wi gëna néew ci LiFePO₄ dafay indi wàññeeku ci kàttanu decharge bu kawe {1}rate bu batëri bi. Doxalinu LiFePOPO bu sell bi mingi tollu ci 10 ⁹S S/cm, te kàttanu decharge dafay wàññeeku bu baax ci 148 mAheh/g ci 0.2C decharge ba 85 mAh/g ci 5C decharge. Kàttan bu kawe {9}) kàttanu decharge ci materiel cathode bi du saa yu nekk di yokku ci yoon. Su amee yoon wu néew, yokkute ci yoon dafay gëna yokk kinetik electrochimique ci macceer bi. Su amee yoon bu ëpp solo bu am solo, yoon wi nekkatul li ñuy wax ci kàttanu macceer bi. LiFe‘iP mAh/g, ci 10C decharge. Loolu dafay wane ni lithium {{24} ion diffusion mën nañu wecci yoon wi muy facteur decisif ci màndarga electrochimique yu lithium {25} ion.

(2) Lithium-ion Lithium {-on diffusion dafay aju ci mbir yu ci biir ak yi ci biti. Facteur yi ci biti ñooy dayo particule yi, distribution bi ak morfoloji. Facteur interne yi dañuy gëna wax ci lithium {5}on koeffisien diffusion. Litium { 7} ion koeffisien diffusion dafay nekk valeur buy wéy; ion litium ion ion dafay gëna wàññeeku su amee dayo particule ndax yoonu diffusion bi ci ion litium yi ci biir particule yi dafay gëna yokk. Diffusion bi am ci ion litium yi mingi méngoo bu baax ak kaare bi ci dayo particule bi, te mën nañu ko méngale ak lithium {9}on coefficient diffusion. Dayo bu am solo bi amna njeexital yu mag ci lithium {11}ré diffusion bu gëna bari koeffisien diffusion. Xayma lithium {) {13} } ion koeffisien diffuffusion dañu ko wara boole ak xeeti natt ak ay xeetu xam-xam. Xeetu natt yi gëna am solo mooy titration galvanostatic (GITT) ak spectroscopie impedance electrochimique (EIS wala Impedance AC).

(3) Ñaari-u electrode scale de générature: electrode electrode yi dañuy gëna yokk liggéeyu electrode bi ci yokk yaatuwaayu surface bi. Ci biir electron yi, electron yi dañuy dugg ci collector courant bi, waaye ion litium yi dañuy dugg ci electrolyte bi ci wàll wi. Ak formation FePO₄ couche, baña jël elektron ci fenomen electron dafay wàññeeku, waaye mbañeel lithium {6} ion dafay gëna yokk. FePO€ nucleate yu njëkk ci ay jafe-jafe kristal, ba noppi di màgg ci wàll yépp, di tere litium-ion diffusion ba ion litium yi mënul daw ci yoon [100].