Battery a bai htang ai lam hpa rai ta?- Polinovel

Battery a bai htang ai lam hpa rai ta?

Ya aten hta, ndai bungli hta LiFePO pri a electrochemical reaction byin pru wa ai lam hpe hkrak tup chye na ai lam n nga ai. Ndai zawn re ai n-gun rawng ai anion an (PO°C)3⁻ hpe jai lang ai gaw, iron- hpe n-gun jaw ai gaw, lithium-ion battery cathodes ni a matu kaja dik ai arung arai langai mi rai nga ai. Raitim, LiFePO% a crystal structure gaw shi a conductivity hte lithium-ion diffusion galaw ai lam hpe pat shingdang ya ai majaw, dai arai a electrochemical bungli hpe shayawm kau ya ai. Layered materials ni hte n bung ai sha, LiMPO pri a charge{6}}discharge curve gaw grai n-gun n rawng ai plateau nga ai, dai gaw lahkawng a laklai ai atsam marai langai mi rai nga ai, lachyum gaw LiMPO₄ hte MPO pri lapran na phase galai shai ai lam gaw lithium-ion intercalation/deintercalation aten hta byin pru wa ai.

Reaction mechanism model

Charge galaw ai aten hta, Li2 gaw FeO₆ layer kaw na htawt sit nna, electrolyte hku lai wa nna, n kaja ai electrode de shang wa ai. Fe2⁺ gaw Fe3⁺ de oxidized galaw ai, electron ni gaw shinggan na circuit kaw nna negative electrode de sa wa ai shaloi, conductive agent hte ya aten na mahkawng da ai wa hku nna hkawm sa ai. Discharge galaw ai lam gaw nhtang wa ai lam re.

Ndai sawk sagawn ai lam lahkawng hpe tsun dan na matu, Padhi hte Goodenough et al. shawng nnan e "core-shell hkrang" hpe tang madun da ai, dai hta lithium-ion a lapran na matut mahkai lam/hkang masa lam gaw LiFePO%/Hpre

Charging galaw ai aten hta, LiFePO°/FePO° interface gaw, npu kaw nna center de matut manoi shamu shamawt nga ai, core de sit sa wa ai. Li2 gaw shinggan de matut manoi htawt sit wa nna, shinggan na LiFePO° gaw FePO°C de matut manoi galai shai wa ai. Lithium ions hte electron ni gaw, nnan hpaw hpang wa ai lahkawng hpe matut manoi lai di nna, kaja ai hka leng hpe n-gun jaw na matu, raitim, lithium-ion diffusion rate gaw, masa nkau mi hta n galai shai ai. Dai daw lahkawng a lapran na matut mahkai lam ni yawm wa ai hte maren, lithium ions ni a garan ginhka ai lam gaw hpang jahtum e, n-gun n rawng ai sha, n-gun n rawng mat na re. Particle core kata na LiFePO% hpe tup hkrak n jai lang na re majaw, atsam n nga mat na re. Charge ngut ai hpang, n lang shi ai LiFePO% gaw particle a lapran kaw naw nga na re.

Lithium ions ni gaw shara law law hta kalang ta shingdaw nna, n-gun n rawng ai hpe myit yu yang, Anderson et al. sumla 4{3}}3b hta madun da ai hte maren, shawng nnan na atsam sum ai lam hpe sang lang dan na matu mosaic model hpe tang madun da ai. Mosaic model gaw lithium ion ion intercalation hte deintercalation galaw ai lam gaw LiFePO%/FePO lahkawng-hpung a lapran kaw nga ai raitim, dai lam gaw particle kata na shara shagu hta byin mai ai ngu tsun ai. Charging galaw ai aten hta, FePO% ginra gaw particle ntsa na shara shagu hta kaba wa nna, ndai ginra ni a jut ni gaw cross-contact byin wa ai majaw, n mai gram lajang lu ai si mat ai shara law law hpe shabyin ya ai majaw, atsam sum mat ai. Discharging galaw ai aten hta, nhtang wa ai lam byin pru wa nna, lithium ions ni gaw FePO pri daw de shang wa ai. Lithium ions ni gaw n-gun n-gun yawm wa ai hpe n-hkap la ai core kaw nga ai daw.

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

Theoretical model lahkawng hpe kalang ta galaw shapraw ai raitim, core{0}}}shell model hpe sawk sagawn ai ni grau nna hkap la ai, raitim, shell hte core a laksan arung arai ni gaw ndang kalang naw rai nga ai. Ndai hkrang lahkawng hpe madung tawn nna, lithium ions hte charge a diffusion kinetics gaw, electrode arung arai yawng hpe tatut jai lang na matu dawdan ya ai lam ni re ngu dawdan mai ai. Lithium iron phosphate cathode arung arai ni hpe hkyen lajang ai hta, kaji ai hte bung ai n-gun (nanoscale or microporoous) hte n-gun rawng ai daw ni hpe lu la na matu shakut ai lam ni hpe galaw ai, carbon coating (nanocarbon film) hte ion doping hpe lang nna, n-gun n-gun hte lithium ion garan ai lam hpe grau kaja hkra galaw ai.

LiMPO arung arai ni hpe grau sung ai hku chye na ai hte, ndai hkrang lahkawng gaw LiMPO arung arai ni hta lithium ion htaw sa ai lam hta grai anisotropic arawn alai ni hpe n yu n hkan galaw ai hpe mu lu ai. Laffont gaw "Core-shell model a n-gun kya ai lam ni hpe sharai la na matu "Core(New Core-shell Model" hpe tang madun da ai. Ndai lam hpe gawgap nna, Delmas gaw LiFePO particles ni hpe n bung ai depletion states ni hta sawk sagawn nna, "Domino-cascade Model" hpe tang madun da ai, dai gaw nanoscale particles ni a lawan ai manu hte pru wa ai lam hpe hkrak hkrak sang lang dan ai, sumla 4-4 hta madun da ai hte maren.

Lahta e tsun lai wa sai hkrang masa ni a lapran hta grai shai hkat ai raitim, madung lam gaw, lahkawng ngu na- cellse interface lahkawng a tau hkrau tsun ai hte masat masa galaw ai lam hta nga ai. Lithium bang/extraction hte phase galai shai ai lam a kinetics ni gaw, dai arung arai a n-gun, hkrang masa, physicochemical atsam ni hta grai madung nga ai majaw, lawu na bawngban ai lam ni (ma ni a lapran na manghkang ni lawm ai) gaw, n law htum chyam dinglik masa ni a majaw rai na re.

Microscopy hte spectroscopy byin pru wa ai hte rau, LiMPO4 arung arai ni a daw galai shai ai aten hta, ngang kang ai hparan ladat hte lapran daw ni hpe mu lu nna, mu lu ai, dai gaw LiMPO4 arung arai ni hta kaga daw galai shai ai ladat langai mi nga chye ai hpe madun nga ai. Kalang lang na solid solution reactions ni hta, cell parameters hte cell volume gaw phase galai shai ai aten hta matut manoi galai shai ai lam ni hpe madun dan ai. ultra-}small particles (nanoscale) zawn re ai grai sawng ai chyam dinglik ai masa ni hte hkrang shapraw ai ladat nkau mi hku nna, LiMPO4 hta ngang kang ai hparan ladat hte lapran daw ni nga ai hpe mu lu ai, ngang kang ai hparan ladat ni a hkam sha lam ni hte ngang kang ai hparan ladat ni hpe mu lu ai.

Phase galai shai ai lam ni hpe manu jahpu- n-gun rawng ai aten hta nta kata na nbung katsi ai aten hta galaw ai. Lithium-ion battery ni gaw charge a- n-gun n-gun shayawm ai aten hta kaja ai hku bai gram lajang lu ai lam hpe madun dan ai, dai gaw lithium-}ion deintercalation/intercalation ngut ai hpang tsun da ai daw lapran na hkrang masa bung ai lam hte seng ai. Charge-discharge galaw ai lam ni hta, battery a n-gun yawm ai lam gaw, phase galai shai ai kinetics hte grai ni htep ai. LiFePO4 a hkrang masa hku nga yang, [100]pmnb lam gaw lithium-ion htawt sit ai lam a matu grau kaja ai, dai daw lahkawng a lapran na matut mahkai lam gaw, charge-dadischarge ladat ni hta c{11}axis hku hkawm sa wa ai.

(1) LiFePO€/FePO€The 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, Li₁₋δFOPO€ a diffraction peak gaw n nga mat wa nna, FePO°C kaw na pru wa ai diffraction peak a n-gun gaw loi loi hte jat wa ai. Dai hte maren, lithium ions ni hpe bang da ai hte maren, FePO% kaw na pru wa ai diffraction peak a n-gun gaw loi loi hte yawm mat wa nna, Li₁₋δFOPO pri a majaw byin pru wa ai diffraction peak a n-gun gaw loi loi hte jat wa ai.

(2) LiₓFePO€/Li₋yFePO€.LiₓFePO₄ at room temperature is a mixture of Fe³⁺/Fe²⁺ mixed-valence mesophase LiₐFePO₄/Li₁₋ FePO₄. hte charge hte discharge galaw ai shaloi carrier density hte hopping probability hpe madi madun ai. Powder neutron diffraction gaw 0.05 hte 0.11 a matu kaja dik ai manu ni hpe mu lu ai. ion doping, temperature, galai shai ai magri, particle size, hte non{6}}equilibrium zawn re ai lam ni gaw, grai law ai shara ni hta, yawng a manu ni hpe hkra machyi shangun ai. Dai majaw, n-gun ja ai hte nta kata na nbung katsi ai aten hta, electrode a n-gun atsam hpe grau kaja hkra galaw ya lu ai.

450℃hta, LiₓFePO€ a ngang kang ai hparan ladat langai mi nga ai, nta kata na nbung katsi ai aten hta, metastable phase lahkawng nga ai: Li₄ 500℃jan , LiₓFePO°C gaw non{5}}olivine compounds ni de hkrat sum hpang wa ai; ndai phosphates (sh) phosphides ni a n-gun hte n-gun gaw x a manu hta madung nga ai. 400 hte 500℃lapran hta, LiₓFePO° a ngang kang ai hparan ladat langai sha nga ai.

Katsi ai aten na galai shai ai lam ni gaw, katsi ai aten hta grau sawng ai. Katsi ai aten hta mixture a composition gaw x a manu hte thermal process a manu hta madung nga ai. Katsi mat ai shaloi, LiₓFePO°C gaw, non{2}}olivine daw lahkawng hpe kayau nna, n-gun n rawng ai daw lahkawng hpe kayau kaya galaw nna, dai a shadawn shadang gaw, nbung laru a shawng nnan na manu hte x a shadawn shadang hta madung nga ai. Katsi ai shara gaw lawu de (140±20℃), lahkawng rai nga ai-}phase system gaw grau sawng ai masa byin wa ai, dai hta LiFePO% hte FePO% yan gaw kaga olivine- amyu lahkawng, LiₓFePO° hte Liₓ⁅FePO° hte rau nga nga ai. Ndai kayau kaya ai lam hpe nta kata na nbung katsi ai shara hta kaba wa ai majaw, LiFePO pri hte FePO pri a lahkawng ngu na-pse system lahkawng de loi loi hte galai shai wa shangun ai.

Battery reaction mechanism

FePO°C gaw npawt nhpang law law hta nga ai: ① LiFePO% hpe tsep kawp n-gun n rawng hkra galaw ngut ai hpang, orthorhombic FePO°C hpe hpaw hpang wa ai; ② Triclinic FePO pri hta quartz- zawn re ai hkrang nga ai, cations yawng hpe tetrahedral coordinated galaw da ai; ③ Monoclinic hte orthombic FePO°C hpe shanhte a hka htung ni kaw na lajang mai ai. Ndai Crystalline hkrang ni yawng hpe FePO%, shing nrai, n-gun n rawng ai FePO% ngu ai hkrang ni yawng hpe, katsi ai aten hta triclinic FePO° de galai shai mai ai.

LiFePO° kaw nna FePO% de galai shai ai lam gaw n-gun n rawng ai hte n hkum tsup ai, raitim, nbung katsi ai gaw 500℃jan ai shaloi ngut kre ai. Battery bungli galaw ai masa hta, cathode material gaw kinetically stable byin ai. LiFePO% hpe hpaw shabawn ai aten hta, FePO% n nga ai hpe kam na matu ahkyak nga ai. Dai shara kaw nga ai rai yang, triclinic FePO°C hpe katsi ai shara kaw shapraw na rai nna, n-gun ja ai nbung laru hta, n-gun rawng ai n-gun rawng ai shingnip hpe n-gun jaw ai lam byin shangun na re.

Ion doping gaw arung arai ni a conductivity hpe grau kaja hkra galaw ya lu ai. P{1}} zawn re ai semiconductor hpe 10⁻2 S/cm de du hkra galaw lu ai arung arai ni hpe ion doping hku nna lu la ai. Doping gaw grai yak hkak ai lam langai mi rai nga ai: maga mi de, buga ginra na n-gun (LDA) a npu na LiFePO° a electronic hkrang masa hpe density functional theory (DFT) hte generalized gradient gradient approximation (GGA) a jahpan ni gaw, dai arai gaw metallic (sh) semiconductor arai langai a arawn alai ni hpe madun dan ra ai, 0.3 eV daram nga ai conduct band hte valence band nga ai hpe madun dan ai. low conductivity gaw teng sha mu lu ai. Maga mi hku nna, ion doping ngut ai hpang, electron orbitals hte Coulomb matut mahkai lam ni a lapran na matut mahkai lam ni hpe myit yu yang, valence band hkrang hpe grau kaja hkra galaw lu ai.

Mg{{0} (sh) Cr{1}ded LiFePO° a DFT jahpan ni hpe yu yang, electronic mungdaw ni a n-gun kaba dik htum gaw Fermi madang makau kaw nga ai hpe madun dan ai, dai gaw doped material a metallic conductivity hpe sang lang dan ai. ion doping a majaw byin pru wa ai conductivity galai shai ai lam gaw lawu na lam ni hte seng mai ai:

1) charge carrier ginra ni a jut ni hpe shinggrup da ai.

2) Ion doping gaw valence band hte conduction band a galu kaba ai lam hpe shayawm ya ai.

4) Dopant ion ni a amyu, myit maju jung ai lam, garan gachyan ai lam ni.

6) Hkrang shapraw ai aten hta, organic carbon hpe jat bang ai gaw, dai arung arai hpe carbon coating byin shangun nna, kaja ai conduction lam hpe shabyin ya ai.

7) Fe₂P a hkrang hpe mu lu ai. Synthesis galaw ai shaloi, carbon grau law ai hpe jat bang ai gaw, phosphate hpe shayawm ya ai.

Ion doping and conductivity

8) Fe3 3⁺/Fe2⁺ redox pair gaw LiFePO pri hpe shayawm ai hta n-gun n rawng ai hku galaw ai.

LiFePO° gaw, lang ai electrolytes ni hte bai htang ai lam hpe madun dan ai. Dai arung arai a electrochemical akyang lailen gaw, electrolyte kata na shi a ntsa na chemistry hte grai matut mahkai nga ai. Madung hku nna, passivation film langai mi gaw, dai arai a ntsa e byin pru wa ai. Ndai sumla hkrung gaw lithium{{3}ion diffusion hpe loi ai hku galaw ya ai, shamu shamawt ai arung arai ni sum mat ai hpe pat shingdang ya ai, lithium-ion bang ai aten hta n-gun hte ntsa lam galai shai ai lam ni hpe hkam sharang ra ai. Carbon- hpe masat da ai LiFePO% ntsa na sumla hkrung ni hta LiF₆, Li kaji Fᵧ⁻, hte Li kaji rau na n-gun rawng ai n-gun ni lawm ai.

Common electrolytes ni hta, n-gun n rawng ai carbonates hte lithium sau ni lawm ai. Cathode a arai gaw electrolyte hta byin mai ai n-gun law law hpe hkam sha ra ai. Ga shadawn, LiPF₆ hka htung ni hta, LiFePO° hte HF a trace law law hpe koi yen n mai ai lam ni hpe n mai koi gam ai. Electrolyte hta HF nga ai gaw, hkra machyi ai lam lahkawng nga ai: langai, magri ions hte proton lapran na galai shai ai lam; hte lahkawng ngu na hta, LiF byin hkra, particle ntsa kaw na Li ions hte F ions ni a bai htang ai lam gaw LiF byin wa ai majaw, Li2 a diffusion hpe pat shingdang nga ai.

Iron ions ni gaw electrolytes ni hta garan mat ai. Electrolytes amyu myu hta LiFePO° hpe garan ginhka ai lam hpe chyam dinglik ai lam ni gaw lawu na lam ni hpe madun dan ai:

1) Acific awu asin n lawm ai electrolytes ni hta, n-gun ja ai shara ni hta pyi, magri ions ni htum mat nna, dai kaw na pru wa ai mass sum mat ai lam gaw, n-gun n rawng ai.

2) Hka hta rawng ai acidity grau law ai majaw, magri ion n-gun yawm mat ai.

4) Dai arung arai kata na carbon law ai gaw, arung arai ni hpe grau ngang grin hkra galaw ya ai.

Active material hte binder lapran na matut mahkai ai shara gaw grau nna n-gun n rawng ai. Ndai n-gun n-gun hpe alkaline mesophase hpe lang ai (sh) acidic scaveng additives ni hpe lang ai hku nna koi lu ai. LiFePO°C hpe lang nna, lithium-ion hta lang ai battery ni hta, n-gun n rawng ai n-gun n-gun n-gun n-nga ai n-gun n-gun n-gun (sh) LiFePO pri ngu ai carbon hpe jat bang ai (sh) n-gun n-htum hkra galaw mai ai.

LiFePO° cathode arung arai ni a kinetic arawn alai ni hpe atsawm n chye na shi ai. Dai majaw, n-gun rawng ai lam hte garan ginhka ai lam, n-gun rawng ai lam, ion diffusion, kinetics ni gaw, daw galai shai ai aten hta (charge{1}} n-gun n-gun n-rawng ai lam), hte carbon coating/doping yawng gaw, n bung ai charge a n bung ai charge a bungli galaw ai lam hpe hkra machyi shangun ai. Carbon doping ngu ai lachyum gaw, shamu shamawt ai arung arai ni hta shara langai kaw sha, lithium ions hte electron ni hpe bang nna shaw la mai ai, electrode polarization hpe shayawm ya lu ai.

(1) Atsam marai hte seng nna, n-gun atsam n-gun atsam gaw, san seng ai LiFePO° a n-gun n law ai majaw, battery a n-gun kaba ai{{1}rate discharge capacity hpe shayawm kau ya ai. Dai pure LiFePO°C a conductivity gaw 10⁻ ⁹ S/cm daram rai nna, 148 mA·h/g kaw nna 0.2C pru ai n-gun hta 5C pru ai n-gun hta 85 mA·h/g de pru wa ai atsam grai yawm mat ai. Cathode a arai ni a tsaw ai-rate discharge capacity gaw, n-gun jat wa ai hte maren galoi mung n jat wa ai. Conductivity n law ai aten hta, n-gun jat wa ai gaw, dai arung arai a electrochemical kinetics hpe grau kaja hkra galaw ya ai. Arung arai ni hpe n-gun jaw ai lam gaw ahkyak ai manu langai ngai hta jan ai shaloi, n-gun rawng ai lam gaw, dai arung arai a manu jahpu a matu dawdan ai lam n rai sai. 1.0 × 10⁻ S/cm), shi a n-gun n law ai, LiFePO° (4.0 × 10⁶ S/cm) hta grau kaja ai n-gun hpe madun dan ai, 90 mA·/g hte 55000. mA·h/g, langai hte langai, 10C shapraw ai n-gun hta. Ndai lam gaw, lithium-ion diffusion gaw, lithium-ion battery ni a electrochemical atsam ni hta dawdan ai lam hku nna, conductivity hpe galai kau ai rai na re ngu tsun mayu ai.

(2) Lithium-ion garan ai Lithium-ion garan ai lam hpe kata lam hte shinggan lam lahkawng yan hku nna dawdan ai. Shinggan na lam ni hta particle size, garan ginhka ai lam, hkrang masa ni lawm ai. Kata lam lam ni gaw madung hku nna lithium-ion diffusion coefficient hpe tsun mayu ai. Lithium-ion garan ai coefficient gaw n galai shai ai manu; lithium ions ni a diffusion atsam gaw particle size law wa ai hte maren yawm mat ai, hpa majaw nga yang, particle kata na lithium ions ni a diffusion lam gaw law wa ai. Lithium ions ni a diffusion atsam gaw particle size a square hte nhtang shadawn shadang rai nna, lithium-ion diffusion coefficient hte hkrak hkrak shingdaw lu ai. Particle size gaw diffusion coefficient hta grau nna lithium-ion diffusion hpe grau nna hkra machyi shangun ai. Lithium-ion garan ai coefficient hpe nambat hku sawn la ai lam hpe shadawn shadang ladat ni hte theoretical model ni hte kayau kaya galaw ra ai. Madung shadawn shadang ladat ni gaw, galvanostattic titration (GITT) hte electrochemical n-gun n-gun (EIS or AC Impedance) ni rai nga ai.

(3) Lahkawng ngu na-dimensional scale electrodes: Thin-film electrode ni gaw, npu lamu ga hpe jat wa ai hku nna, electrode a shamu shamawt lam hpe jat ya ai. Thin{4}}film electrodes ni hta, electron ni gaw ya na mahkawng da ai wa de shang nna, lithium ions ni gaw electrolyte de n bung ai maga kaw nna shang wa ai. FePO° layer byin pru wa ai hte rau, electron shamu shamawt ai lam hpe ninghkap lu ai atsam yawm mat wa nna, lithium-ion shamu shamawt ai lam hpe ninghkap lu ai atsam gaw grau law wa ai. FePO₄ gaw, n-gun n rawng ai shara ni hta shawng nnan e nucleate galaw nna, maga shagu de kaba wa ai, lithium ions ni [100] maga de n mai hprawng mat ai aten du hkra, lithium-ion garan ai lam hpe pat shingdang ai.