hanyang university information and communication materials lab. polymer electrolyte 공업화학과...

Hanyang UniversityHanyang University

Information and Communication Materials Lab.Information and Communication Materials Lab.

Polymer Electrolyte

공업화학과 / 정보통신소재연구실 / 석사 2 기

이 인 재

2000.11.27

Lithium secondary batteryHistorical backgroundElectrochemical processCell configurationClassificationsRequirements

Ionic Conductivity

Polymer electrolyte RequirementsAdvantageIon conduction mechanismSolid Polymer electrolyteGel Polymer electrolyte



Lithium secondary battery

Historical Background Electrochemical Process of Lithium secondary battery1789 개구리다리로부터 전지현상발견 (Galbani(Ital

y)) 1799 구리 -아연 전지 발명 (Cu/H2SO4/Zn,Volta(Italy)) 1860 연축전지 발명 (PbO2/H2SO4/Pb,Plante'(France)) 1867 망간 건전지의 원형 발명 (MnO2/NH4Cl.ZnCl2/Zn,Lechlanche(France)) 1899 니켈 -카드뮴 전지 발명 (NiOOH/KOH/Cd,Jungner(Sweden)) 1899 니켈 -아연 전지 발명 (NiOOH/KOH/Zn) 1900 니켈 -철 전지 발명 (NiOOH/KOH/Fe,Edison(USA)) 1909 알카리 망간전지 발명 (MnO2/KOH/Zn) 1917 공기 아연전지 발명 (O2 in Air/KOH/Zn) 1942 수은전지 발명 (HgO/KOH/Zn) 1970 리튬 1 차전지실용화 1970 미국 GM Delco 칼슘 MF 연축전지 개발 1973 이산화망간 -리튬 1 차전지 실용화 (MnO2/LiClO4/Li) 1981 리튬 이온 2차전지발명 1990 리튬 이온 2차전지실용화 ,생산개시 (일본 SONY 사 ) 1990 밀폐형 닉켈 -수소전지실용화 (NiOOH/KOH/MH) 1990 미국 켈리포니아주 대기정화법 (Clean Air Act) 통과 세계각국 전기자동차용 전지 본격적인 개발 1995 수은전지 생산중지

Cathode LiMO2 Li1-xMO2+xLi+xe

Anode C6+xLi+xe LixC

Overall LiMO2+C6 LixO6+Li1-xMO2

Charge

Discharge

Charge

Discharge

Charge

Discharge

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



Cell Configuration• Cathode

LiCoO2 LiNixCo1-xO2 LiNiO2 LiMn2O4 LiMnO2

결정구조 Layered Layered Layered Spinel Layered

이론용량(mAh/g) 274 275 275 148 285

실제용량(mAh/g) >135 >185 >160 >120 >190

평균전압(V)

3.6 3.6 3.6 3.8 ~2.8,~3.4

Cost high moderate moderate low Low

• Anode

음극물질 무게당 용량 (mAh/g)

부피당 용량 (mAh/l)

C6(Coke)(50% 사용시 ) 186 372

C6(graphite) 372 515

Li metal(25% 사용시 ) 965 837

Li metal(100% 사용시 3861 2062

• 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



이론 용량과 실제 용량

Faraday’s Low of Electrolysis ; 1g 당량의 원자 또는 원자단이 석출하는데 필요한 전기량은 물질에 관계없이 항상 일정한

96487C 을 갖는다 .

Ex)Li1-xMO2(M=Co, Ni, Mn, …)

1. LiCoO2(MW=97.87)

1F=96487C=96487A s • 1h/3600s 1000mA/A = 26800mAh

∴ 26800mAh/97.87g = 273mAh/g ⇒ LiCoO2 의 이론용량

실제용량은 x=0.5 이하이므로 137mAh/g

2. Li1-xMn2O4(MW=180.8)

똑같은 계산으로 26800mAh/180.8g = 148mAh/g

Spinel structure 의 Li1-xMn2O4 는 x=1 이므로 실제용량이 이론용량값과 거의 일치



Classifications of Requirements of Lithium secondary battery Lithium secondary battery

Lithium IonLithium Ion

PolymerLithium Metal

Polymer

음극 탄소 탄소 리튬

전해질 액체 전해질 고분자 전해질 고분자 전해질

양극

금속 산화물(LiCoO2, LiN2O2, LiMn2O4

등 )

금속 산화물(LiCoO2, LiN2O2,

LiMn2O4 등 )

금속 산화물 , 유기 Sulfur, 전도성 고분자

평균전압 3.6V 3.6V 2.0~3.6V

에너지밀도 High High Very High

사이클특성 Excellent High Poor

저온특성 Good Medium Poor

안전성 Poor Medium Good

Cell 디자인 자유도 Poor Good Good

용도 및 개발시기

3C 시장91 년 Sony

3C 시장97 년 Ultralif

e

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



Ionic Conductivity

Basic concept

= 1/ = /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/) (I/A=current density, V/=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 value 를 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

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



Polymer electrolyte

Requirements of Polymer electrolyte

High ion conductivity (≥10-3S/cm @ R.T)

Good compatibility between polymer matrix and liquid electrolyte

Thermal and electrochemical stability

Good mechanical stability

High cation transference number

Availability

Advantage of Polymer electrolyteDesign flexibility

High energy density

Thin film

No leakage of liquid electrolyte

Low cost

Ion Conduction Mechanism

Solid polymer electrolyte

Gel polymer electrolyte

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

Lithium cation dissociated by organic solvent

Transported through the free volume or micropore polymer matrix and liquid electrolyte

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



Solid polymer electrolyte

Second GenerationHigh molecular weigh amorphous or reduced crystallinity polyether-based host architectures

•Random copolymer•Comb-branched copolymer•Network

Gel electrolytes:systems containing low molecular weight solvent

PEO <10-8S/cm

Tg=-64℃

PPO <10-8S/cm

-60℃

Polyester

Polyamine

Polysulfide

10-5~10-8S/cm @60℃

CH2CH2On

CH2CH2O

CH3n

OCH2CH2OC(CH2)CO

O O nCH2CH2CO

On

CH2CH2NHn

CH2CH2NRn

R=CH3,C3H7

CH2 Snm

Random polyether

POO 3 10-8S/cm

-66℃

CH2O CH2CH2O



MEEP

10-5S/cm

-83℃(amorphous)N P

O(CH2CH2O)2CH3

O(CH2CH2O)2CH3

Comb-branched copolymer

PMG 1 10-8S/cm

-50℃(amorphous)CH2C

CH3

OO(CH2CH2O)9CH3

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)

CH2CH2O CH2CHO

CH2OCH2CH2OCH2CH2OCH3

x 1-x n

SiO(CH2CH2O)4

CH3

CH3

n

Si

CH3

O(CH2CH2O)12CH3

On

Si

CH3

CH2CH2CH2O(CH2CH2O)12CH3

O

n

Siloxane-based

10-4S/cm

10-4~10-5S/cm



1.4 10-3 @ 60℃3.3 10-4 @ 40℃

(Nishimoto et al, J. Power Sources, 1999, 81-82, 786)

P(EO/MEEGE)73/27 Poly((amino)[(2-methoxyethoxy)ethoxy])phosphazenes

(Y.W.chen-Yang et al, macromolecules, 2000, 33, 1237)

Tg=-65~-50℃

Improve dimensional stability



NetworksPoly(propylene oxide)

(M. Watanabe, N. Ogata, in “Polymer Electrolyte Reviews”, 1987, 39)

PEO based(via thermal with crosslinker)

(Nishimoto et al, Solid State Ionics, 1995, 79, 306)

Ion conductivity of polymer 4 and polymer 5



(Nishimoto et al, Macromolecules, 1999, 32, 1541)

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℃

PEO based(via photo)



Gel Polymer electrolytePAN/MEEP based

(L.M.Abraham, M.Alamgir, J.Electrochem.Soc., 1990, 137, 1657)

PVC based

(M. Watanabe, A. Nishimoto, Solid State Ionics, 1996, 86-88, 385)



PVdF based

(J. Y. Song et al, J. Electrochem. Soc., 2000, 147, 3219)

Acrylate based

S. I. Moon et al, J. Power Sources, 2000, 87, 213



(Wolfgang H.Meyer, Adv. Mater., 1998, 10, 439P.Baum, W. H. Meyer, G. Wegner, Polymer, 2000, 41, 965)

Poly(p-phenylene) based

hanyang university information and communication materials lab. polymer electrolyte 공업화학과...

Documents