Polymer Electrolyte

1
Polymer Electrolyte
?????/?????????/??2? ? ? ? 2000.11.27

• Lithium secondary battery
• Historical background
• Electrochemical process
• Cell configuration
• Classifications
• Requirements
• Ionic Conductivity

• Polymer electrolyte
• Requirements
• Advantage
• Ion conduction mechanism
• Solid Polymer electrolyte
• Gel Polymer electrolyte

2
Lithium secondary battery
Linden, Handbook of batteries, 1994 Jang Myoun
Ko, Polymer Science ang Technology, 1998, 9,
203 Yang Kook Sun, Prospectives of Industrial
chemistry, 2000, 3, 11

• Historical Background

Electrochemical Process of Lithium secondary
battery
1789 ???????? ?????? (Galbani(Italy)) 1799 ??-??
?? ?? (Cu/H2SO4/Zn,Volta(Italy)) 1860 ????
??(PbO2/H2SO4/Pb,Plante'(France)) 1867 ?? ????
?? ??(MnO2/NH4Cl.ZnCl2/Zn,Lechlanche(France))
1899 ??-??? ?? ?? (NiOOH/KOH/Cd,Jungner(Sweden))
1899 ??-?? ?? ??
(NiOOH/KOH/Zn) 1900 ??-? ?? ??
(NiOOH/KOH/Fe,Edison(USA)) 1909 ??? ????
??(MnO2/KOH/Zn) 1917 ?? ????
??(O2 in Air/KOH/Zn) 1942 ????
??(HgO/KOH/Zn) 1970 ?? 1??????
1970
?? GM Delco ?? MF ???? ??
1973 ?????-?? 1??? ???(MnO2/LiClO4/Li) 1981 ??
??2????? 1990 ??
??2??????,????(?? SONY?) 1990 ???
??-???????(NiOOH/KOH/MH) 1990 ?? ??????
?????(Clean Air Act)?? ???? ?????? ?? ???? ??
1995 ???? ????
3
Cell Configuration

• Cathode

LiCoO2 LiNixCo1-xO2 LiNiO2 LiMn2O4 LiMnO2
???? Layered Layered Layered Spinel Layered
????(mAh/g) 274 275 275 148 285
????(mAh/g) gt135 gt185 gt160 gt120 gt190
????(V) 3.6 3.6 3.6 3.8 2.8,3.4
Cost high moderate moderate low Low

• Anode

• Electrolyte
• Solid polymer electrolyte Lithium salt
• Gel polymer electrolyte Lithium Salt Solvent
• Lithium salt LiClO4, Li(CF3SO2)2N, LiCF3SO3,
• LiAsF6, LiPF6, LiBF6
• Solvent PC, EC, DMC, EMC, DEC, ?-BL, etc

???? ??? ??(mAh/g) ??? ??(mAh/l)
C6(Coke)(50???) 186 372
C6(graphite) 372 515
Li metal(25???) 965 837
Li metal(100??? 3861 2062
4
?? ??? ?? ??

• Faradays Low of Electrolysis
• 1g??? ?? ?? ???? ????? ??? ???? ??? ???? ??
  ???
• 96487C? ???.
• Ex)Li1-xMO2(MCo, Ni, Mn, )
• LiCoO2(MW97.87)
• 1F96487C96487As ? 1h/3600s ? 1000mA/A
  26800mAh
• ? 26800mAh/97.87g 273mAh/g ? LiCoO2 ?
  ????
• ????? x0.5????? 137mAh/g
• Li1-xMn2O4(MW180.8)
• ??? ???? 26800mAh/180.8g 148mAh/g
• Spinel structure? Li1-xMn2O4? x1???
  ????? ?????? ?? ??

5
Classifications of Requirements
of Lithium secondary battery Lithium
secondary battery
Lithium Ion Lithium Ion Polymer Lithium Metal Polymer
?? ?? ?? ??
??? ?? ??? ??? ??? ??? ???
?? ?? ??? (LiCoO2, LiN2O2, LiMn2O4 ?) ?? ??? (LiCoO2, LiN2O2, LiMn2O4 ?) ?? ???, ?? Sulfur, ??? ???
???? 3.6V 3.6V 2.03.6V
????? High High Very High
????? Excellent High Poor
???? Good Medium Poor
??? Poor Medium Good
Cell ??? ??? Poor Good Good
?? ? ???? 3C?? 91? Sony 3C?? 97? Ultralife 3C, EV(???) ???

• Energy density(Wh/g or Wh/l)
• WhAh(??) ? V(??)
• Cycle life (100 DOD ??)
• Rate performance (C-Rate)
• ??????
• ??-2060?, ??040?
• ?? ?? (????, ?????)
• ?? ??
• ???
• Memory effect
• ?? ???
• Cost
• ????

6
Ionic Conductivity
Richard G. Compton, Giles H.W. Sanders, Electrode
Potentials, 1996 Peter G. Bruce, in Polymer
Electrolyte Reviews, ed. By J.R.MacCallum, 1987,
237

• Measurements of conductivity
• Direct current measurement(D.C.)
• simple, straightforward method
• conductivity value? ?? ??
• Alternating current measurement(A.C.)
• Vmax/Imaxthe ratio of the voltage and current
• maxima
• ? the phase difference between the voltage
• and current
• Impedance ?Z?f(Vmax/Imax,,?)
• ZZ-jZ Resistor ?0, ?Z?R
• Capacitor ? -2/?, ?Z?1/?C

• Basic concept
• ? 1/? l/RA
• Where, ?conductivity(?-1m-1),?resistivity,
• Rresistance
• Conductivity is a property of the chemical nature
  and composition of the electrolyte solution
• Ohms low VIR ? ?(I/A)/(V/l)
• (I/Acurrent density, V/lvoltage
  gradient)
• Basic electrical properties of a polymer
  electrolyte
• 1)the total conductivity of the electrolyte as a
  function of Temp.
• 2)identification of the different charged
  species contributing to conduction
• 3)transport numbers, i.e. the proportion of the
  current carried by each charged species, as a
  function of Temp.

7
Polymer electrolyte
Fiona M. Gray, Polymer Electrolyte, 1997
Peter V. Wright, Br. Polym. J.,
1975, 7, 319 Jung Ki Park, Polymer Science and
Technology, 1998, 9, 125 ????, ???
??, 2000

• Requirements of Polymer electrolyte

• Ion Conduction Mechanism

• High ion conductivity (10-3S/cm _at_ R.T)
• Good compatibility between polymer matrix and
  liquid electrolyte
• Thermal and electrochemical stability
• Good mechanical stability
• High cation transference number
• Availability

• Solid polymer electrolyte

Low barriers to rotation for atoms in the main
chain so as to ensure high flexibility and hence
facilitate segmental motion
Advantage of Polymer electrolyte

• Gel polymer electrolyte

• Design flexibility
• High energy density
• Thin film
• No leakage of liquid electrolyte
• Low cost

Lithium cation dissociated by organic
solvent Transported through the free volume or
micropore polymer matrix and liquid electrolyte
8
Solid polymer electrolyte
Second Generation

• PEO ?lt10-8S/cm
• Tg-64?
• PPO ?lt10-8S/cm
• -60?
• Polyester
• Polyamine
• Polysulfide
• 10-510-8S/cm _at_60?

• High molecular weigh amorphous or reduced
  crystallinity polyether-based host architectures
• Random copolymer
• Comb-branched copolymer
• Network
• Gel electrolytessystems containing low molecular
  weight solvent

• Random polyether
• POO 3 ? 10-8S/cm
• -66?

9

• Comb-branched copolymer
• PMG 1 ? 10-8S/cm
• 
  -50?(amorphous)

P(EO/MEEGE) P(EO/MEEGE)-5 (955)
-61? P(EO/MEEGE)-9 (919) -65?
(M. Watanabe, A. Nishimoto, Electrochimica Acta,
1998, 43, 1177)
MEEP
10-5S/cm
-83?(amorphous)
10
P(EO/MEEGE)73/27
Poly((amino)(2-methoxyethoxy)ethoxy)phosphazenes
Tg-65-50? Improve dimensional stability
1.4 ? 10-3 _at_ 60? 3.3 ? 10-4 _at_ 40? (Nishimoto et
al, J. Power Sources, 1999, 81-82, 786)
(Y.W.chen-Yang et al, macromolecules, 2000, 33,
1237)
11
Networks
Poly(propylene oxide)
PEO based(via thermal with crosslinker)
(Nishimoto et al, Solid State Ionics, 1995, 79,
306)
Ion conductivity of polymer 4 and polymer 5
(M. Watanabe, N. Ogata, in Polymer Electrolyte
Reviews, 1987, 39)
12
PEO based(via photo)
P(EO/MEEGE)470 -68.0? P(EO/MEEGE)500
68.9? P(EO/MEEGE)710
68.6? P(EO/MEEGE)850
71.3? P(EO/MEEGE)990
68.7? P(EO/MEEGE)1500
67.4? P(EO/MEEGE)2000 66.7?
(Nishimoto et al, Macromolecules, 1999, 32, 1541)
13
Gel Polymer electrolyte
PAN/MEEP based
PVC based
(M. Watanabe, A. Nishimoto, Solid State Ionics,
1996, 86-88, 385)
(L.M.Abraham, M.Alamgir, J.Electrochem.Soc.,
1990, 137, 1657)
14
PVdF based
Acrylate based
(J. Y. Song et al, J. Electrochem. Soc., 2000,
147, 3219)
S. I. Moon et al, J. Power Sources, 2000, 87, 213
15
Poly(p-phenylene) based
(Wolfgang H.Meyer, Adv. Mater., 1998, 10,
439 P.Baum, W. H. Meyer, G. Wegner, Polymer,
2000, 41, 965)