1. Polymer Electrolyte 공업화학과/정보통신소재연구실/석사2기 이 인 재 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 개구리다리로부터 전지현상발견 (Galbani(Italy)) 1799 구리-아연 전지 발명 (Cu/H2SO4/Zn,Volta(Italy)) 연축전지 발명(PbO2/H2SO4/Pb,Plante'(France)) 망간 건전지의 원형 발명(MnO2/NH4Cl.ZnCl2/Zn,Lechlanche(France)) 니켈-카드뮴 전지 발명 (NiOOH/KOH/Cd,Jungner(Sweden)) 니켈-아연 전지 발명 (NiOOH/KOH/Zn) 니켈-철 전지 발명 (NiOOH/KOH/Fe,Edison(USA)) 1909 알카리 망간전지 발명(MnO2/KOH/Zn) 공기 아연전지 발명(O2 in Air/KOH/Zn) 수은전지 발명(HgO/KOH/Zn) 리튬 1차전지실용화 미국 GM Delco 칼슘 MF 연축전지 개발 이산화망간-리튬 1차전지 실용화(MnO2/LiClO4/Li) 1981 리튬 이온2차전지발명 리튬 이온2차전지실용화,생산개시(일본 SONY사) 1990 밀폐형 닉켈-수소전지실용화(NiOOH/KOH/MH) 미국 켈리포니아주 대기정화법(Clean Air Act)통과 세계각국 전기자동차용 전지 본격적인 개발 수은전지 생산중지
Cathode LiMO Li1-xMO2+xLi+xe
Anode C6+xLi+xe LixC
Overall LiMO2+C LixO6+Li1-xMO2
Charge
Discharge

3. Cell Configuration Cathode Anode Electrolyte
LiCoO2
LiNixCo1-xO2
LiNiO2
LiMn2O4
LiMnO2
결정구조
Layered
Spinel
이론용량(mAh/g)
274
275
148
285
실제용량(mAh/g)
>135
>185
>160
>120
>190
평균전압(V)
3.6
3.8
~2.8,~3.4
Cost
high
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
음극물질
무게당 용량(mAh/g)
부피당 용량(mAh/l)
C6(Coke)(50%사용시)
186
372
C6(graphite)
515
Li metal(25%사용시)
965
837
Li metal(100%사용시
3861
2062

4. 이론 용량과 실제 용량 Faraday’s Low of Electrolysis
; 1g당량의 원자 또는 원자단이 석출하는데 필요한 전기량은 물질에 관계없이 항상 일정한
96487C을 갖는다.
Ex)Li1-xMO2(M=Co, Ni, Mn, …)
LiCoO2(MW=97.87)
1F=96487C=96487A•s  1h/3600s  1000mA/A = 26800mAh
∴ 26800mAh/97.87g = 273mAh/g ⇒ LiCoO2 의 이론용량
실제용량은 x=0.5이하이므로 137mAh/g
Li1-xMn2O4(MW=180.8)
똑같은 계산으로 26800mAh/180.8g = 148mAh/g
Spinel structure의 Li1-xMn2O4는 x=1이므로 실제용량이 이론용량값과 거의 일치

5. Classifications of Requirements of Lithium secondary battery Lithium secondary battery
Lithium Ion
Lithium Ion Polymer
Lithium Metal Polymer 음극 탄소 리튬
전해질
액체 전해질
고분자 전해질 양극
금속 산화물
(LiCoO2, LiN2O2, LiMn2O4 등)
금속 산화물, 유기 Sulfur, 전도성 고분자
평균전압
3.6V
2.0~3.6V
에너지밀도
High
Very High
사이클특성
Excellent
Poor
저온특성
Good
Medium
안전성
Cell 디자인 자유도
용도 및
개발시기
3C시장
91년 Sony
97년 Ultralife
3C, EV(대용량)
개발중
Energy density(Wh/g or Wh/l)
Wh=Ah(용량)  V(전압)
Cycle life (100% DOD 기준)
Rate performance (C-Rate)
작동온도구간
방전;-20~+60℃, 충전;0~40℃
보존 특성 (충전보존, 가역성보존)
자기 방전
안전성
Memory effect
형상 자유성
Cost
환경문제

6. Ionic Conductivity Measurements of conductivity Basic concept
Richard G. Compton, Giles H.W. Sanders, Electrode Potentials, 1996
Peter G. Bruce, in “Polymer Electrolyte Reviews”, ed. By J.R.MacCallum, 1987, 237
Basic concept
 = 1/ = l/RA
Where, =conductivity(-1m-1),=resistivity,
R=resistance
Conductivity is a property of the chemical nature and composition of the electrolyte solution
Ohm’s low V=IR ∴ =(I/A)/(V/l)
(I/A=current density, V/l=voltage 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.
Measurements of conductivity
Direct current measurement(D.C.)
simple, straightforward method
conductivity value를 바로 얻음
Alternating current measurement(A.C.)
Vmax/Imax:the ratio of the voltage and current
maxima
 : the phase difference between the voltage
and current
Impedance Z=f(Vmax/Imax,,)
Z*=Z’-jZ” Resistor : =0, Z=R
Capacitor :  =-2/, Z=1/C

7. Polymer electrolyte Requirements of Polymer electrolyte
Fiona M. Gray, Polymer Electrolyte, Peter V. Wright, Br. Polym. J., 1975, 7, 319
Jung Ki Park, Polymer Science and Technology, 1998, 9, 한원길역, 폴리머 전지, 2000
Requirements of Polymer electrolyte
Ion Conduction Mechanism
High ion conductivity 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
PEO <10-8S/cm
Tg=-64℃
PPO <10-8S/cm
-60℃
Polyester
Polyamine
Polysulfide
Second Generation
High molecular weigh amorphous or reduced crystallinity polyether-based host architectures
Random copolymer
Comb-branched copolymer
Network
Gel electrolytes:systems containing low molecular weight solvent
Random polyether
POO  10-8S/cm
-66℃

9. Comb-branched copolymer
PMG  10-8S/cm
-50℃(amorphous)
P(EO/MEEGE)
P(EO/MEEGE)-5 (95:5) -61℃
P(EO/MEEGE)-9 (91:9) -65℃
(M. Watanabe, A. Nishimoto, Electrochimica Acta, 1998, 43, 1177)
Siloxane-based
10-4S/cm
10-4~10-5S/cm
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  60℃
3.3  40℃
(Nishimoto et al, J. Power Sources, 1999, 81-82, 786)
(Y.W.chen-Yang et al, macromolecules, 2000, 33, 1237)

11. Ion conductivity of polymer 4 and polymer 5
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) ℃
P(EO/MEEGE) –68.9℃
P(EO/MEEGE) –68.6℃
P(EO/MEEGE) –71.3℃
P(EO/MEEGE) –68.7℃
P(EO/MEEGE) –67.4℃
P(EO/MEEGE) –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)