1 Poly Elect total
Polymer Electrolytes
Jong Hak Kim
Chemical Engineering
Yonsei University
Polym e r Ele c t rolyt e s (PEs)
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N e w e st solid ionic s : for E ge ne ra t ion, st ora ge , dist ribut ion
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Applic a t ions t o e le c t roc he m ic a l de vic e s
Synt he sis of ne w polym e r e le c t rolyt e s
Physic a l st udie s of t he ir st ruc t ure & c ha rge t ra nsport
T he ore t ic a l m ode ling of c ha rge t ra nsport proc e sse s
Cha rge t ra nsport m e c ha nism s
- I norga nic : ion “hopping m e c ha nism ”
- PEs: loc a l m ot ion of polym e r (se gm e nt a l m ot ion) in t he vic init y
of t he ion
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T w o ge ne ra l t ype s
- polym e r/sa lt c om ple x : c oordina t ion P + sa lt (PEO/LiClO 4 )
- polye le c t rolyt e s: c ova le nt ly a t t a c he d c ha rge d group
Solid I onic s
● Cryst a lline solid e le c t rolyt e s
- H + , Li + , N a + , K + , Ag + , F -, O 2 -, & di- or t riva le nt ions c onduc t ors
- (i) a high c onc e nt ra t ion of m obile ions, (ii) a low a c t iva t ion
e ne rgy for ionic m ot ion from sit e t o sit e
- c onduc t ivit y: hopping m e c ha nism a long c ha nne ls
- in c ryst a l st ruc t ure : 1 -, 2 -, 3 -D ne t w ork of c ha nne ls
● Gla ss e le c t rolyt e s : a m orphous solid c onduc t ors
● M olt e n e le c t rolyt e s
- m olt e n sa lt s or m ix t ure s high c onduc t ivit ie s (> 1 Sc m -1 )
- e .g., LiCl-K Cl e ut e c t ic (m .p. 3 5 5 °C < LiCl a t 6 1 3 °C)
- Dra w ba c k : high ope ra t ion T & c orrosion
● Polym e ric e le c t rolyt e s
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good int e rfa c ia l c ont a c t s w it h e le c t rode m a t e ria ls (not brit t le )
Conduc t ivit y (by 1 0 0 ~1 0 0 0 ) < t ha n Liq. or c e ra m ic e le c t rolyt e s
t hin film c onfigura t ion c om pe nsa t e for t he low e r va lue s
● Prope rt ie s of polym e r e le c t rolyt e
- a de qua t e c onduc t ivit y for pra c t ic a l purpose s
- low e le c t ronic c onduc t ivit y
- good m e c ha nic a l prope rt ie s
- high c he m ic a l, e le c t roc he m ic a l a nd phot oc he m ic a l
st a bilit y
- e a se of proc e ssing
Funda m e nt a ls of polym e r e le c t rolyt e
1 . Solve nt (liquid) fre e syst e m : ionic a lly c onduc t ing pha se is
form e d by dissolving sa lt s in polym e r.
2 . Ge l e le c t rolyt e : form e d by dissolving sa lt in pola r liquid a nd
a dding ina c t ive polym e ric m a t e ria l.
3 . Pla st ic ize d e le c t rolyt e : e sse nt ia lly a ge l e le c t rolyt e but is
usua lly a ssoc ia t e d w it h t he a ddit ion of sm a ll a m ount s of a
high die le c t ric c onst a nt solve nt t o e nha nc e it s c onduc t ivit y
4 . I onic rubbe r: a liquid e le c t rolyt e c om prising a low
t e m pe ra t ure m olt e n sa lt m ix t ure , re duc e d t o a rubbe ry
c ondit ion by a ddit ion of a sm a ll a m ount of high M w polym e r
5 . M e m b ionom e r, H + c onduc t ing polye le c t rolyt e , c om prising
fluoroc a rbon ba c k bone t o w hic h sulfonic a c id a re bonde d
c he m ic a lly. e .g. N a fion. (w it h pla st ic ize r)
T he rm odyna m ic s of sa lt dissolut ion
● Dissolut ion of sa lt s → re duc t ion in ∆G of t he syst e m a t
c onst a nt T & P → c onside r ∆H , ∆S
∆G = ∆H - T ∆S
● Ove ra ll e nt ropy c ha nge on dissolut ion
(+) : due t o t he bre a k up of c ryst a l la t t ic e a nd t he subse que nt
disorde ring of ions in t he syst e m
(−) : c a use d by t he st iffe ning of c ha ins a s t he y c oordina t e t o
c a t ions
● M a jor e nt ha lpy c ha nge s on dissolut ion
(+) : due t o t he la t t ic e e ne rgy of t he sa lt
(−) : due t o c a t ion solva t ion
Polym e r solve nt s
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A polym e r t ha t is c a pa ble of st rongly c oordina t ing c a t ions
polye t he rs, polye st e rs, polyim ine s, polyt hiols
ha ve st rong c oordina t ing groups t o dissolve sa lt s e a sily
H igh M w PEO-ba se d polym e r e le c t rolyt e s
- poor c onduc t ors in c ryst a lline
- a m orphous; loss of m e c ha nic a l st a bilit y
● At a c t ic PPO
- a m orphous sinc e ra ndom a rra nge m e nt of m e t hyl group
● Ra ndom polye t he rs
(-(OCH 2 CH 2 ) m -OCH 2 -) n : a m orphous, dim e t hyl silox y unit s
● Com b-bra nc he d c opolym e rs
- e nha nc e fle x ibilit y of t he syst e m & c onduc t ivit y
● N e t w ork s
- highe r ionic c onduc t ivit y & dim e nsiona l st a bilit y by
opt im ize d c rosslink ing
H ost Polym e rs
Rubbe ry & Am orphous
● PEO
- T < 6 0 °C, pre se nc e of c ryst a lline pa rt → re duc e c onduc t ivit y
● At a c t ic poly(propyle ne ox ide ), PPO
- ra ndom a rra nge m e nt of CH 3 a long t he c ha in
→ pre ve nt t he orde r ne c e ssa ry for c ryst a lliza t ion of polym e r
→ not be st e le c t rolyt e (∵st e ric hindra nc e of CH 3 side group)
1 ) lim it s t he se gm e nt a l m ot ion
2 ) re duc e s polym e r-c a t ion int e ra c t ion
● Poly (m e t hyle ne ox ide ), (CH 2 O) n
- supe rfic ia lly good be c a use of it s high c onc . pola r groups
- but not good in pra c t ic e sinc e ha rd w it h high c ohe sive e ne rgy
● Am orphous poly(e t hyle ne ox ide ), PEO
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c onsist s of m e dium but ra ndom ly-va ria ble le ngt h se gm e nt s of
PEO joine d by m e t hyle ne ox ide unit s
→ m e t hyle ne ox ide unit s bre a k up t he re gula r he lic a l pa t t e rn of
PEO a nd suppre ss c ryst a lliza t ion
● PEO w it h DM S unit s
- int roduc e d bt n. PEO unit s t o produc e a n a m orphous polym e r
● Am orphous c om b polym e rs
- short c ha in polye t he rs a t t a c he d t o a polyphospha ze ne or a
polysilox a ne ba c k bone
- e x c e lle nt host s for a lk a li m e t a l sa lt s sinc e high fle x ibilit y of
PN ba c k bone t o prom ot e ion t ra nsport
● Bra nc he d & N e t w ork polym e r ionic s
- a t a m ic rosc opic le ve l, t he de gre e of c rosslink ing m ust not be
so gre a t a s t o m a k e t he loc a l polym e r se gm e nt s rigid, t he re by
inc re a sing T g a nd re duc ing ion t ra nsport
- c he m ic a l c rosslink ing st ra t e gy → c he m ic a l or irra dia t ion
c rosslink ing
● Addit ive s: sm a ll pola r m ole c ule s int o PEs
- im prove m e nt in c onduc t ivit y
i) pla st ic ize polym e r → high fle x ibilit y & se gm e nt a l m ot ion
ii) solva t e c a t ion (or a nion) → re duc e ion-ion int e ra c t ions
- e .g., propyle ne c a rbona t e
poly(a c rylonit rile ) & poly(vinyl pyrrolidone ) + LiClO 4 + PC
→ high c onduc t ivit ie s (1 .7 x 1 0 -3 a t 2 0 °C)
● Addit ive s: sm a ll c he la t ing a ge nt s
- short c ha in poly(e t hyle ne glyc ol), c yc lic polye t he rs
- bre a k up ion-ion int e ra c t ions
Ot he r Polym e r H ost s
Sa lt s
● Polya t om ic a nions w it h m onova le nt c ha rge a re t he be st
c a ndida t e s (∵ w e a k a nion solva t ion).
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e .g., w a t e r soluble LiF (st rong solva t ion of F by w at e r)
→ LiF insoluble in PEO
→ LiClO 4 highly soluble in PEO
● La rge , pola riza ble , m onova le nt a nions low la t t ic e E
→ be t t e r dissolut ion
→ ClO 4 -, CF 3 SO 3 -, (CF 3 SO 2 ) 2 N -, (CF 3 SO 2 ) 3 C -, AsF 6 -, PF 6 → I - & Br - (but Cl -, F - poor solubilit y)
● Solva t ion H of sa lt de pe nds on c a t ion-polym e r int e ra c t ion
→ dissolut ion only oc c urs if a t om s w hic h a re c a pa ble of
c oordina t ing t he c a t ions a re a va ila ble on t he polym e r c ha ins
● We a k e r solva t ion of (-CH 2 -O-) n & (-CH 2 -CH 2 -CH 2 -O-) n
- t he c ha ins w ra p a round c a t ion w it hout e x c e ss st ra in
→ right spa c ing of (-CH 2 -CH 2 -O-) n unit
- ot he r c oordina t ion groups: -N R- , -N H - a nd –S● I nt e ra c t ion st re ngt h bt n. c a t ion a nd c oordina t ing group
c la ssifie d a c c ording t o ha rd/soft a c id ba se t he ory (H SAB)
→ H A pre fe r H B a nd SA do SB; e .g., polye t he r vs Li +
1 ) ha rd/soft a c ids
(a ) ha rd: sm a ll c a t ions w it h no va le nc e e le c t rons,
e .g., a lk a li, a lk a line e a rt h ions, M g 2 +
(b) soft : la rge r c a t ions w it h se ve ra l va le nc e e le c t rons, H g 2 +
2 ) ha rd/soft ba se s
(a ) ha rd: non-pola riza ble liga nds of high e le c t rone ga t ivit y (-O-)
(b) soft : m ore pola riza ble groups, e .g., t hio group
-O- > -N H - > -S-
Polye le c t rolyt e s
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M a t e ria ls t ha t ha ve polym e ric ba c k bone s w it h c ova e
l nt ly
bonde d ionizing groups a t t a c he d t o t he m
Com m on func t iona l group: SO3 -, COO -, N H 3 + , = N H 2 +
Ge l e le c t rolyt e s
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Gre a t int e re st c om m e rc ia lly a s a lt e rna t ive t o t he solve nt -fre e
syst e m s → highe r, m ore pra c t ic a l ionic c onduc t ivit ie s
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Form e d by dissolving sa lt in pola r liquid a nd a ddin g polym e r
ne t w ork t o give t he m a t e ria l m e c ha nic a l st a bilit y
• T w o m e t hods t o a c hie ve m a c rosc opic im m obiliza t ion of solv.
1 ) inc re a se t he visc osit y of liq. e le c t rolyt e by a dding soluble
polym e r, e .g., PEO, PM M A, PAN unt il ge l c onsist e nc y is
a c hie ve d
2 ) loa d t he liq. e le c t rolyt e int o m ic roporous m a t rix , e .g., porous
polye t hyle ne
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Low m ole c ula r solve nt s
propyle ne c a rbona t e (PC), e t hyle ne c a rbona t e (EC),
N ,N -dim e t hyl form a m ide (DM F), γ-but yrola c t one (GBL)
high die le c t ric c onst a nt , high B.P.
inc re a se sa lt dissoc ia t ion
low visc osit y → high ionic m obilit y
Polym e ric m a t e ria ls: PAN , PV DF, PV C, PM M A
Be llc ore (U SA) Co.
- c om m e rc ia lly a va ila ble ge l e le c t rolyt e (for Li ba t t e ry)
- PV dF-c o-H FP (he x a fluoropropyle ne ) e le c t rolyt e
(Li sa lt solut ion in m ix e d c a rbona t e e st e rs)
- H FP → de c re a se c ryst a llinit y of PV dF c om pone nt & e nha nc ing
it s a bilit y t o a bsorb liquid
- H ybrid polym e r e le c t rolyt e : porous polym e r w it h < subm ic ron
+ orga nic solve nt
Break ???
M e c ha nism s of ion c onduc t ion
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‘dry’ polym e r e le c t rolyt e :
polym e r it se lf is im m obile
(m a c rosc opic a lly)
→ ions a re t ra nsport e d by t he
se m i-ra ndom m ot ion of
short polym e r se gm e nt s
H ow ions t ra nsport e d ?
Solve nt & ion t ra nsport
• c a t ions in liquids or low MW polym e r; ions c a n m ove t oge t he r w it h
t he ir c oordina t e d solve nt , not in high M W polym e r
• Whe n MW > 3 2 0 0 g/m ol, M W of polym e r ha s no signific a nt e ffe c t on
c a t ion m obilit y.
• For high MW polym e r host s,
- c ha in diffusion is sm a ll a nd m a k e s lit t le c ont ribut ion t o
m e c ha nism for ion t ra nsport
- t he m ot ion of ions in polym e r e le c t rolyt e s is st rongly
de pe nde nt on se gm e nt a l m ot ion of t he polym e r host
● Dyna m ic bond pe rc ola t ion t he ory (DBP)
- M ic rosc opic m ode l → c onduc t ivit y due t o c om bina t ion of
ion/polym e r c oope ra t ive m ot ion w it h t he oc c a siona l
inde pe nde nt ion m ove m e nt .
- T im e sc a le for t he la t t e r is m uc h short e r t ha n for polym e r
re la x a t ion, diffe re nt c a t ion a nd a nion m ot ions.
• c a t ion→ m a k ing a nd bre a k ing of c oordina t e bonds w it h
m ot ion be t w e e n c oordina t ing sit e s
• a nion → hopping be t w e e n oc c upie d sit e a nd void
M a c rosc opic a pproa c h
● Em piric a l re la t ionship: c onduc t ivit y vs. t e m pe ra t ure
- a m orphous PEs de pa rt from t he c la ssic a l Arrhe nius re la t ion
σ = σ0 e x p [ - E a / k B T ]
- V oge l-T a m m a n-Fulc he r (V T F) e qua t ion: ions a re t ra nsport e d by
se m i-ra ndom m ot ion of short polym e r se gm e nt s
σ = σ0 e x p [ - B / (T -T 0 ) ]
● Fre e volum e -ba se d m ode ls: m ot ion oc c urs a s a re sult of t he
re dist ribut ion of fre e volum e w it hin t he syst e m
● Configura t iona l e nt ropy m ode l: ba se d upon e nt ropy, not volum e ,
w it h t ra nsport m ode le d on group c oope ra t ive re a rra nge m e nt s
of polym e r c ha ins ra t he r t ha n a void-t o-void jum ping
m e c ha nism
M orphology
● Ge ne ra l t e c hnique s t o c ha ra c t e rize polym e r e le c t rolyt e
st ruc t ure a nd m orphology
- opt ic a l m ic rosc opy, DSC, N M R, X RD
● Pha se dia gra m s
Pre pa ra t ive T e c hnique s
● Solve nt -fre e e le c t rolyt e film
1 ) Solve nt c a st ing
c a st ing → solve nt e va p. → he a t ing unde r va c uum
2 ) H ot pre ssing m e t hod
- grinding polym e r & sa lt a t liquid N 2 T e m p. → hot
pre sse d
; t ot a lly solve nt fre e
● Ge l e le c t rolyt e film : im port a nc e of polym e r m a t rix
Suit a ble polym e r e le c t rolyt e s?
● M inim um re quire m e nt s
- ionic c onduc t ivit y: 1 0 -2 – 1 0 -3 Sc m -1 ide a l a t RT
(m in. 1 0 -5 Sc m -1 for pra c t ic a l use )
- e le c t roc he m ic a l st a bilit y in a volt a ge w indow -c om pa t ibilit y:
c he m ic a lly & e le c t roc he m ic a lly c om pa t ible w it h e le c t rode s
- T he rm a l st a bilit y
- M e c ha nic a l st a bilit y
- Ava ila bilit y: a va ila ble & ine x pe nsive
● Ele c t rode -e le c t rolyt e int e rfa c e
- diffe re nt int e rfa c ia l proc e sse s, e .g., e le c t ron t ra nsfe r
m e c ha nism s
● Lit hium a node
- lit hium m e t a l/PEO → t hin la ye r of t hird pha se form e d be t w e e n
t w o bulk pha se s
- pa ssive la ye r c om posit ion: LiF (for LiCF 3 SO 3 e le c t rolyt e ) or Li 2 O
(for LiClO 4 e le c t rolyt e s), inhom oge ne ous
→ low ionic c onduc t ivit y
● I nt e rc a la t ion c a t hode
- provide a m e c ha nism for re ve rsible a nd k ine t ic a lly fa st solidst a t e e le c t roc he m ic a l re a c t ions
- Li se c onda ry ba t t e ry, e le c t roc hrom ic s, se nsors, sola r c e lls
M X n + a Li + + a e - → Li a M X n
- e .g., V 2 O 5 /PEO e le c t rolyt e s w it h LiClO 4
- t w o se m ic irc le in a .c . im pe da nc e
→ high fre que nc y se m ic irc le ; ionic a lly c onduc t ing surfa c e la ye r
t ha t grow s on t he V 2 O 5
→ low fre que nc y se m ic irc le ; c ha rge t ra nsfe r be t w e e n surfa c e
la ye r a nd t he e le c t rode
- t ot a l int e rfa c ia l re sist a nc e ; m a ny t im e s gre a t e r t ha n bulk
re sist a nc e → m inim ize !!
● N a noc om posit e polym e r e le c t rolyt e s
M ix e d pha se e le c t rolyt e s & na noc om posit e s
• c e ra m ic or gla ssy e le c t rolyt e s vs. polym e r e le c t rolyt e s
- highe r c onduc t ivit y, be t t e r t he rm odyna m ic st a bilit y
• polym e r vs. c e ra m ic /gla ssy e le c t rolyt e s
- fle x ible , supe rior int e rfa c ia l c ont a c t s
- proc e sse d a s t hin la rge a re a film s
• m ix e d pha se PEs-c e ra m ic s of na nom e t e r gra in size
⇒ na noc om posit e s
• Conduc t ivit y: a be ne fic ia l e ffe c t of c e ra m ic a ddit ive s
• I nt e rfa c ia l prope rt ie s: I m prove d st a bilit y by na noc om posit e
- re sist a nc e of int e rfa c ia l pa ssiva t ion la ye r
• Why c e ra m ic or gla ss pow de r re nde r t he int e rfa c e m ore st a ble ?
1 ) Re a c t ivit y
: form a t ion of highly c onduc t ing produc t (Li 3 N ) t o fa c ilit a t e ion
t ra nsport
2 ) Shie lding e ffe c t
: c e ra m ic /gla ss re duc e t he c ont a c t be t w e e n Li a nd polym e r
● Prot on c onduc t ors
→ a nhydrous c onduc t ors: PEO-H 3 PO 4 , PEI -H 2 SO 4 or H 3 PO 4 , PV PH 3 PO 4 ; high c onduc t ivit y (∵ high int rinsic c onduc t ivit y of a c id)
→ prot on-va c a nc y c onduc t ing polym e rs: PEO n N H 2 SO 2 N H 2
→ hydra t e d prot on c onduc t ing m e m bra ne s: polye le c t rolyt e + w a t e r
→ polym e r e le c t rolyt e fue l c e ll e m ploy hydra t e d pe rfluorosulfonic
a c id suc h a s N a fion (DuPont ), Dow X U S-1 3 2 0 4 .1 0 , Chlorine
Engine e rs M e m bra ne C
Conduc t ing Polym e r
Polym e r e le c t rode s : c onjuga t e d polym e r
Polya c e t yle ne
• (CH )x ; room T c onduc t ivit y;
1 0 -5 Sc m -1 for t ra ns, 1 0 -9 Sc m -1 for c is
● Ex posure t o ox idizing or re duc ing a ge nt s
→ inc re a se se ve ra l orde rs of c onduc t ivit y
e .g., e x posure t o ha loge ns: poor c onduc t or a pproa c hing t ha t of
m e t a ls
Doping proc e ss
● p-doping proc e ss
- e x posure t o ox idizing a ge nt (X )
- form a t ion of posit ive ly c ha rge d polym e r c om ple x &
re duc t ion of X
(CH ) x → [(CH y+ )] x + (x y)e (x y)X + (x y)e - → (x y)X w it h t ot a l re a c t ion
(CH ) x + (x y)X → [(CH y+ )] x + (x y)X - → [(CH y+ )X y -] x
w he re X - = I -, Br -…
X - → dopa nt c ount e r a nion
y: ra t io bt n. dopa nt ion a nd polym e r re pe a t ing unit
→ doping le ve l
● n-doping proc e ss
- e x posure t o re duc ing a ge nt (M )
- form a t ion of ne ga t ive ly c ha rge d polym e r c om ple x &
ox ida t ion of M
(CH ) x + (x y)e - → [(CH y-)] x
(x y)M → (x y)M + + (x y)e w it h t ot a l re a c t ion
(CH ) x + (x y)M → [(CH y-)] x + (x y)M + → [M y +(CH y-)] x
w he re M + = N a + , Li + … → dopa nt c ount e r c a t ion
● H e t e roc yc lic polym e rs
• polypyrrole & polyt hiophe ne
● Polya c e t yle ne
• de ge ne ra t e ground st a t e ; t w o ge om e t ric st ruc t ure s wit h
sa m e e ne rgy a nd diffe re nt se que nc e single -double bonds
● Polya niline
• pre pa re d e le c t roc he m ic a lly, by ox ida t ion of a niline in a c id
m e dia
• doping → not induc e c ha nge s in t he num be r of e le c t rons
a ssoc ia t e d w it h t he polym e r c ha in, but re la t e d t o a highly
sym m e t ric a l π- de loc a lize d st ruc t ure
• c onduc t ivit y vs. T ; polym e r ~ SC
M e c ha nism of doping proc e sse s
• “doping”: sa m e t e rm inology w it h inorga nic se m ic onduc t or, but t he
doping proc e sse s of c onduc t ing polym e rs a re quit e diffe re nt from
t hose of inorga nic se m ic onduc t ors
● Se m ic onduc t or: rigid la t t ic e , doping is w e ll de sc ribe d by ba nd m ode ls
→ doping proc e sse s; int roduc t ion of im purit ie s int o t he c ryst a l la t t ic e
w it h t he int e rga p e ne rgy le ve ls ne a r CB or V B; c onduc t ion proc e e ds
via a c ohe re nt propa ga t ion of e le c t rons a nd/or hole s a c ross t he la t t ic e
● Polym e r: fle x ible c ha ins, fa vor loc a lize d c ha in de form a t ion → im purit ie s
or doping a ge nt s do not be c om e pa rt of t he st ruc t ure , ra t he r a re
inse rt e d w it hin t he polym e r c ha in & c a n be e a sily re m ove d by a pplying
a n opposit e e le c t ric a l driving forc e ; doping proc e ss a re re ve rsible ; t he
spinle ss bipola ronsor solit ons t ra nsport t he c urre nt
M e c ha nism of doping proc e sse s
● T w o c ont ribut ions
- I nt ra c ha in t ra nsport : a ve ra ge c onjuga t ion le ngt h of c ha ins
- I nt e rc ha in t ra nsport : re gula rit y of polym e r st ruc t ure
(∵c onduc t ivit y inc re a se s by orde ring of st ruc t ure )
● M e t hods for m onit oring t he doping proc e sse s
- Opt ic a l a bsorpt ion: int e rga p t ra nsit ion c ha nge s a bsorpt ion
- in sit u spe c t roe le c t roc he m ic a l c e ll m e a sure m e nt
- M ic roba la nc e (QCM , qua rt z c ryst a l )
- Cyc lic volt a m m e t ry & a .c . im pe da nc e
e .g., CV of (CH ) x in LiClO 4 -PC:
a nodic (doping) & c a t hodic (undoping) pe a k s
→ re ve rsible proc e ss, t w o st ruc t ura l sit e s, long t a il: diffusion
c ont rolle d k ine t ic s
Applic a t ion of polym e r e le c t rode
● Ba t t e rie s ; lit hium /polypyrrole ba t t e rie s
Li / LiClO 4 -PC / (C 4 H 5 N ) v
Cha ra c t e rize d by t he follow ing e le c t roc he m ic a l proc e ss:
c ha rge
(C 4 H 5 N ) v + (x y)LiClO 4
disc ha rge
(C 4 H 5 N 3 + )(ClO 4 -) x y ] v +(x y)Li
● Opt ic a l displa y (e le c t roc hrom ic de vic e )
Li / LI ClO 4 -PC / [C 5 H 7 S]v , I T O, gla ss
Displa y is a ba t t e ry w it h a c olor c ha nge .
Ele c t ro-c he m ic a l proc e ss:
doping
[C 5 H 7 S] v + (x y)LiClO 4
(re d)
undoping
[(C 5 H 7 S 7 + )(ClO 4 -) x y ] v + (x y)Li
(blue )
Jong Hak Kim
Chemical Engineering
Yonsei University
Polym e r Ele c t rolyt e s (PEs)
●
N e w e st solid ionic s : for E ge ne ra t ion, st ora ge , dist ribut ion
-
●
Applic a t ions t o e le c t roc he m ic a l de vic e s
Synt he sis of ne w polym e r e le c t rolyt e s
Physic a l st udie s of t he ir st ruc t ure & c ha rge t ra nsport
T he ore t ic a l m ode ling of c ha rge t ra nsport proc e sse s
Cha rge t ra nsport m e c ha nism s
- I norga nic : ion “hopping m e c ha nism ”
- PEs: loc a l m ot ion of polym e r (se gm e nt a l m ot ion) in t he vic init y
of t he ion
●
T w o ge ne ra l t ype s
- polym e r/sa lt c om ple x : c oordina t ion P + sa lt (PEO/LiClO 4 )
- polye le c t rolyt e s: c ova le nt ly a t t a c he d c ha rge d group
Solid I onic s
● Cryst a lline solid e le c t rolyt e s
- H + , Li + , N a + , K + , Ag + , F -, O 2 -, & di- or t riva le nt ions c onduc t ors
- (i) a high c onc e nt ra t ion of m obile ions, (ii) a low a c t iva t ion
e ne rgy for ionic m ot ion from sit e t o sit e
- c onduc t ivit y: hopping m e c ha nism a long c ha nne ls
- in c ryst a l st ruc t ure : 1 -, 2 -, 3 -D ne t w ork of c ha nne ls
● Gla ss e le c t rolyt e s : a m orphous solid c onduc t ors
● M olt e n e le c t rolyt e s
- m olt e n sa lt s or m ix t ure s high c onduc t ivit ie s (> 1 Sc m -1 )
- e .g., LiCl-K Cl e ut e c t ic (m .p. 3 5 5 °C < LiCl a t 6 1 3 °C)
- Dra w ba c k : high ope ra t ion T & c orrosion
● Polym e ric e le c t rolyt e s
-
good int e rfa c ia l c ont a c t s w it h e le c t rode m a t e ria ls (not brit t le )
Conduc t ivit y (by 1 0 0 ~1 0 0 0 ) < t ha n Liq. or c e ra m ic e le c t rolyt e s
t hin film c onfigura t ion c om pe nsa t e for t he low e r va lue s
● Prope rt ie s of polym e r e le c t rolyt e
- a de qua t e c onduc t ivit y for pra c t ic a l purpose s
- low e le c t ronic c onduc t ivit y
- good m e c ha nic a l prope rt ie s
- high c he m ic a l, e le c t roc he m ic a l a nd phot oc he m ic a l
st a bilit y
- e a se of proc e ssing
Funda m e nt a ls of polym e r e le c t rolyt e
1 . Solve nt (liquid) fre e syst e m : ionic a lly c onduc t ing pha se is
form e d by dissolving sa lt s in polym e r.
2 . Ge l e le c t rolyt e : form e d by dissolving sa lt in pola r liquid a nd
a dding ina c t ive polym e ric m a t e ria l.
3 . Pla st ic ize d e le c t rolyt e : e sse nt ia lly a ge l e le c t rolyt e but is
usua lly a ssoc ia t e d w it h t he a ddit ion of sm a ll a m ount s of a
high die le c t ric c onst a nt solve nt t o e nha nc e it s c onduc t ivit y
4 . I onic rubbe r: a liquid e le c t rolyt e c om prising a low
t e m pe ra t ure m olt e n sa lt m ix t ure , re duc e d t o a rubbe ry
c ondit ion by a ddit ion of a sm a ll a m ount of high M w polym e r
5 . M e m b ionom e r, H + c onduc t ing polye le c t rolyt e , c om prising
fluoroc a rbon ba c k bone t o w hic h sulfonic a c id a re bonde d
c he m ic a lly. e .g. N a fion. (w it h pla st ic ize r)
T he rm odyna m ic s of sa lt dissolut ion
● Dissolut ion of sa lt s → re duc t ion in ∆G of t he syst e m a t
c onst a nt T & P → c onside r ∆H , ∆S
∆G = ∆H - T ∆S
● Ove ra ll e nt ropy c ha nge on dissolut ion
(+) : due t o t he bre a k up of c ryst a l la t t ic e a nd t he subse que nt
disorde ring of ions in t he syst e m
(−) : c a use d by t he st iffe ning of c ha ins a s t he y c oordina t e t o
c a t ions
● M a jor e nt ha lpy c ha nge s on dissolut ion
(+) : due t o t he la t t ic e e ne rgy of t he sa lt
(−) : due t o c a t ion solva t ion
Polym e r solve nt s
•
•
•
•
A polym e r t ha t is c a pa ble of st rongly c oordina t ing c a t ions
polye t he rs, polye st e rs, polyim ine s, polyt hiols
ha ve st rong c oordina t ing groups t o dissolve sa lt s e a sily
H igh M w PEO-ba se d polym e r e le c t rolyt e s
- poor c onduc t ors in c ryst a lline
- a m orphous; loss of m e c ha nic a l st a bilit y
● At a c t ic PPO
- a m orphous sinc e ra ndom a rra nge m e nt of m e t hyl group
● Ra ndom polye t he rs
(-(OCH 2 CH 2 ) m -OCH 2 -) n : a m orphous, dim e t hyl silox y unit s
● Com b-bra nc he d c opolym e rs
- e nha nc e fle x ibilit y of t he syst e m & c onduc t ivit y
● N e t w ork s
- highe r ionic c onduc t ivit y & dim e nsiona l st a bilit y by
opt im ize d c rosslink ing
H ost Polym e rs
Rubbe ry & Am orphous
● PEO
- T < 6 0 °C, pre se nc e of c ryst a lline pa rt → re duc e c onduc t ivit y
● At a c t ic poly(propyle ne ox ide ), PPO
- ra ndom a rra nge m e nt of CH 3 a long t he c ha in
→ pre ve nt t he orde r ne c e ssa ry for c ryst a lliza t ion of polym e r
→ not be st e le c t rolyt e (∵st e ric hindra nc e of CH 3 side group)
1 ) lim it s t he se gm e nt a l m ot ion
2 ) re duc e s polym e r-c a t ion int e ra c t ion
● Poly (m e t hyle ne ox ide ), (CH 2 O) n
- supe rfic ia lly good be c a use of it s high c onc . pola r groups
- but not good in pra c t ic e sinc e ha rd w it h high c ohe sive e ne rgy
● Am orphous poly(e t hyle ne ox ide ), PEO
-
c onsist s of m e dium but ra ndom ly-va ria ble le ngt h se gm e nt s of
PEO joine d by m e t hyle ne ox ide unit s
→ m e t hyle ne ox ide unit s bre a k up t he re gula r he lic a l pa t t e rn of
PEO a nd suppre ss c ryst a lliza t ion
● PEO w it h DM S unit s
- int roduc e d bt n. PEO unit s t o produc e a n a m orphous polym e r
● Am orphous c om b polym e rs
- short c ha in polye t he rs a t t a c he d t o a polyphospha ze ne or a
polysilox a ne ba c k bone
- e x c e lle nt host s for a lk a li m e t a l sa lt s sinc e high fle x ibilit y of
PN ba c k bone t o prom ot e ion t ra nsport
● Bra nc he d & N e t w ork polym e r ionic s
- a t a m ic rosc opic le ve l, t he de gre e of c rosslink ing m ust not be
so gre a t a s t o m a k e t he loc a l polym e r se gm e nt s rigid, t he re by
inc re a sing T g a nd re duc ing ion t ra nsport
- c he m ic a l c rosslink ing st ra t e gy → c he m ic a l or irra dia t ion
c rosslink ing
● Addit ive s: sm a ll pola r m ole c ule s int o PEs
- im prove m e nt in c onduc t ivit y
i) pla st ic ize polym e r → high fle x ibilit y & se gm e nt a l m ot ion
ii) solva t e c a t ion (or a nion) → re duc e ion-ion int e ra c t ions
- e .g., propyle ne c a rbona t e
poly(a c rylonit rile ) & poly(vinyl pyrrolidone ) + LiClO 4 + PC
→ high c onduc t ivit ie s (1 .7 x 1 0 -3 a t 2 0 °C)
● Addit ive s: sm a ll c he la t ing a ge nt s
- short c ha in poly(e t hyle ne glyc ol), c yc lic polye t he rs
- bre a k up ion-ion int e ra c t ions
Ot he r Polym e r H ost s
Sa lt s
● Polya t om ic a nions w it h m onova le nt c ha rge a re t he be st
c a ndida t e s (∵ w e a k a nion solva t ion).
•
e .g., w a t e r soluble LiF (st rong solva t ion of F by w at e r)
→ LiF insoluble in PEO
→ LiClO 4 highly soluble in PEO
● La rge , pola riza ble , m onova le nt a nions low la t t ic e E
→ be t t e r dissolut ion
→ ClO 4 -, CF 3 SO 3 -, (CF 3 SO 2 ) 2 N -, (CF 3 SO 2 ) 3 C -, AsF 6 -, PF 6 → I - & Br - (but Cl -, F - poor solubilit y)
● Solva t ion H of sa lt de pe nds on c a t ion-polym e r int e ra c t ion
→ dissolut ion only oc c urs if a t om s w hic h a re c a pa ble of
c oordina t ing t he c a t ions a re a va ila ble on t he polym e r c ha ins
● We a k e r solva t ion of (-CH 2 -O-) n & (-CH 2 -CH 2 -CH 2 -O-) n
- t he c ha ins w ra p a round c a t ion w it hout e x c e ss st ra in
→ right spa c ing of (-CH 2 -CH 2 -O-) n unit
- ot he r c oordina t ion groups: -N R- , -N H - a nd –S● I nt e ra c t ion st re ngt h bt n. c a t ion a nd c oordina t ing group
c la ssifie d a c c ording t o ha rd/soft a c id ba se t he ory (H SAB)
→ H A pre fe r H B a nd SA do SB; e .g., polye t he r vs Li +
1 ) ha rd/soft a c ids
(a ) ha rd: sm a ll c a t ions w it h no va le nc e e le c t rons,
e .g., a lk a li, a lk a line e a rt h ions, M g 2 +
(b) soft : la rge r c a t ions w it h se ve ra l va le nc e e le c t rons, H g 2 +
2 ) ha rd/soft ba se s
(a ) ha rd: non-pola riza ble liga nds of high e le c t rone ga t ivit y (-O-)
(b) soft : m ore pola riza ble groups, e .g., t hio group
-O- > -N H - > -S-
Polye le c t rolyt e s
•
•
M a t e ria ls t ha t ha ve polym e ric ba c k bone s w it h c ova e
l nt ly
bonde d ionizing groups a t t a c he d t o t he m
Com m on func t iona l group: SO3 -, COO -, N H 3 + , = N H 2 +
Ge l e le c t rolyt e s
•
Gre a t int e re st c om m e rc ia lly a s a lt e rna t ive t o t he solve nt -fre e
syst e m s → highe r, m ore pra c t ic a l ionic c onduc t ivit ie s
•
Form e d by dissolving sa lt in pola r liquid a nd a ddin g polym e r
ne t w ork t o give t he m a t e ria l m e c ha nic a l st a bilit y
• T w o m e t hods t o a c hie ve m a c rosc opic im m obiliza t ion of solv.
1 ) inc re a se t he visc osit y of liq. e le c t rolyt e by a dding soluble
polym e r, e .g., PEO, PM M A, PAN unt il ge l c onsist e nc y is
a c hie ve d
2 ) loa d t he liq. e le c t rolyt e int o m ic roporous m a t rix , e .g., porous
polye t hyle ne
•
•
•
Low m ole c ula r solve nt s
propyle ne c a rbona t e (PC), e t hyle ne c a rbona t e (EC),
N ,N -dim e t hyl form a m ide (DM F), γ-but yrola c t one (GBL)
high die le c t ric c onst a nt , high B.P.
inc re a se sa lt dissoc ia t ion
low visc osit y → high ionic m obilit y
Polym e ric m a t e ria ls: PAN , PV DF, PV C, PM M A
Be llc ore (U SA) Co.
- c om m e rc ia lly a va ila ble ge l e le c t rolyt e (for Li ba t t e ry)
- PV dF-c o-H FP (he x a fluoropropyle ne ) e le c t rolyt e
(Li sa lt solut ion in m ix e d c a rbona t e e st e rs)
- H FP → de c re a se c ryst a llinit y of PV dF c om pone nt & e nha nc ing
it s a bilit y t o a bsorb liquid
- H ybrid polym e r e le c t rolyt e : porous polym e r w it h < subm ic ron
+ orga nic solve nt
Break ???
M e c ha nism s of ion c onduc t ion
•
‘dry’ polym e r e le c t rolyt e :
polym e r it se lf is im m obile
(m a c rosc opic a lly)
→ ions a re t ra nsport e d by t he
se m i-ra ndom m ot ion of
short polym e r se gm e nt s
H ow ions t ra nsport e d ?
Solve nt & ion t ra nsport
• c a t ions in liquids or low MW polym e r; ions c a n m ove t oge t he r w it h
t he ir c oordina t e d solve nt , not in high M W polym e r
• Whe n MW > 3 2 0 0 g/m ol, M W of polym e r ha s no signific a nt e ffe c t on
c a t ion m obilit y.
• For high MW polym e r host s,
- c ha in diffusion is sm a ll a nd m a k e s lit t le c ont ribut ion t o
m e c ha nism for ion t ra nsport
- t he m ot ion of ions in polym e r e le c t rolyt e s is st rongly
de pe nde nt on se gm e nt a l m ot ion of t he polym e r host
● Dyna m ic bond pe rc ola t ion t he ory (DBP)
- M ic rosc opic m ode l → c onduc t ivit y due t o c om bina t ion of
ion/polym e r c oope ra t ive m ot ion w it h t he oc c a siona l
inde pe nde nt ion m ove m e nt .
- T im e sc a le for t he la t t e r is m uc h short e r t ha n for polym e r
re la x a t ion, diffe re nt c a t ion a nd a nion m ot ions.
• c a t ion→ m a k ing a nd bre a k ing of c oordina t e bonds w it h
m ot ion be t w e e n c oordina t ing sit e s
• a nion → hopping be t w e e n oc c upie d sit e a nd void
M a c rosc opic a pproa c h
● Em piric a l re la t ionship: c onduc t ivit y vs. t e m pe ra t ure
- a m orphous PEs de pa rt from t he c la ssic a l Arrhe nius re la t ion
σ = σ0 e x p [ - E a / k B T ]
- V oge l-T a m m a n-Fulc he r (V T F) e qua t ion: ions a re t ra nsport e d by
se m i-ra ndom m ot ion of short polym e r se gm e nt s
σ = σ0 e x p [ - B / (T -T 0 ) ]
● Fre e volum e -ba se d m ode ls: m ot ion oc c urs a s a re sult of t he
re dist ribut ion of fre e volum e w it hin t he syst e m
● Configura t iona l e nt ropy m ode l: ba se d upon e nt ropy, not volum e ,
w it h t ra nsport m ode le d on group c oope ra t ive re a rra nge m e nt s
of polym e r c ha ins ra t he r t ha n a void-t o-void jum ping
m e c ha nism
M orphology
● Ge ne ra l t e c hnique s t o c ha ra c t e rize polym e r e le c t rolyt e
st ruc t ure a nd m orphology
- opt ic a l m ic rosc opy, DSC, N M R, X RD
● Pha se dia gra m s
Pre pa ra t ive T e c hnique s
● Solve nt -fre e e le c t rolyt e film
1 ) Solve nt c a st ing
c a st ing → solve nt e va p. → he a t ing unde r va c uum
2 ) H ot pre ssing m e t hod
- grinding polym e r & sa lt a t liquid N 2 T e m p. → hot
pre sse d
; t ot a lly solve nt fre e
● Ge l e le c t rolyt e film : im port a nc e of polym e r m a t rix
Suit a ble polym e r e le c t rolyt e s?
● M inim um re quire m e nt s
- ionic c onduc t ivit y: 1 0 -2 – 1 0 -3 Sc m -1 ide a l a t RT
(m in. 1 0 -5 Sc m -1 for pra c t ic a l use )
- e le c t roc he m ic a l st a bilit y in a volt a ge w indow -c om pa t ibilit y:
c he m ic a lly & e le c t roc he m ic a lly c om pa t ible w it h e le c t rode s
- T he rm a l st a bilit y
- M e c ha nic a l st a bilit y
- Ava ila bilit y: a va ila ble & ine x pe nsive
● Ele c t rode -e le c t rolyt e int e rfa c e
- diffe re nt int e rfa c ia l proc e sse s, e .g., e le c t ron t ra nsfe r
m e c ha nism s
● Lit hium a node
- lit hium m e t a l/PEO → t hin la ye r of t hird pha se form e d be t w e e n
t w o bulk pha se s
- pa ssive la ye r c om posit ion: LiF (for LiCF 3 SO 3 e le c t rolyt e ) or Li 2 O
(for LiClO 4 e le c t rolyt e s), inhom oge ne ous
→ low ionic c onduc t ivit y
● I nt e rc a la t ion c a t hode
- provide a m e c ha nism for re ve rsible a nd k ine t ic a lly fa st solidst a t e e le c t roc he m ic a l re a c t ions
- Li se c onda ry ba t t e ry, e le c t roc hrom ic s, se nsors, sola r c e lls
M X n + a Li + + a e - → Li a M X n
- e .g., V 2 O 5 /PEO e le c t rolyt e s w it h LiClO 4
- t w o se m ic irc le in a .c . im pe da nc e
→ high fre que nc y se m ic irc le ; ionic a lly c onduc t ing surfa c e la ye r
t ha t grow s on t he V 2 O 5
→ low fre que nc y se m ic irc le ; c ha rge t ra nsfe r be t w e e n surfa c e
la ye r a nd t he e le c t rode
- t ot a l int e rfa c ia l re sist a nc e ; m a ny t im e s gre a t e r t ha n bulk
re sist a nc e → m inim ize !!
● N a noc om posit e polym e r e le c t rolyt e s
M ix e d pha se e le c t rolyt e s & na noc om posit e s
• c e ra m ic or gla ssy e le c t rolyt e s vs. polym e r e le c t rolyt e s
- highe r c onduc t ivit y, be t t e r t he rm odyna m ic st a bilit y
• polym e r vs. c e ra m ic /gla ssy e le c t rolyt e s
- fle x ible , supe rior int e rfa c ia l c ont a c t s
- proc e sse d a s t hin la rge a re a film s
• m ix e d pha se PEs-c e ra m ic s of na nom e t e r gra in size
⇒ na noc om posit e s
• Conduc t ivit y: a be ne fic ia l e ffe c t of c e ra m ic a ddit ive s
• I nt e rfa c ia l prope rt ie s: I m prove d st a bilit y by na noc om posit e
- re sist a nc e of int e rfa c ia l pa ssiva t ion la ye r
• Why c e ra m ic or gla ss pow de r re nde r t he int e rfa c e m ore st a ble ?
1 ) Re a c t ivit y
: form a t ion of highly c onduc t ing produc t (Li 3 N ) t o fa c ilit a t e ion
t ra nsport
2 ) Shie lding e ffe c t
: c e ra m ic /gla ss re duc e t he c ont a c t be t w e e n Li a nd polym e r
● Prot on c onduc t ors
→ a nhydrous c onduc t ors: PEO-H 3 PO 4 , PEI -H 2 SO 4 or H 3 PO 4 , PV PH 3 PO 4 ; high c onduc t ivit y (∵ high int rinsic c onduc t ivit y of a c id)
→ prot on-va c a nc y c onduc t ing polym e rs: PEO n N H 2 SO 2 N H 2
→ hydra t e d prot on c onduc t ing m e m bra ne s: polye le c t rolyt e + w a t e r
→ polym e r e le c t rolyt e fue l c e ll e m ploy hydra t e d pe rfluorosulfonic
a c id suc h a s N a fion (DuPont ), Dow X U S-1 3 2 0 4 .1 0 , Chlorine
Engine e rs M e m bra ne C
Conduc t ing Polym e r
Polym e r e le c t rode s : c onjuga t e d polym e r
Polya c e t yle ne
• (CH )x ; room T c onduc t ivit y;
1 0 -5 Sc m -1 for t ra ns, 1 0 -9 Sc m -1 for c is
● Ex posure t o ox idizing or re duc ing a ge nt s
→ inc re a se se ve ra l orde rs of c onduc t ivit y
e .g., e x posure t o ha loge ns: poor c onduc t or a pproa c hing t ha t of
m e t a ls
Doping proc e ss
● p-doping proc e ss
- e x posure t o ox idizing a ge nt (X )
- form a t ion of posit ive ly c ha rge d polym e r c om ple x &
re duc t ion of X
(CH ) x → [(CH y+ )] x + (x y)e (x y)X + (x y)e - → (x y)X w it h t ot a l re a c t ion
(CH ) x + (x y)X → [(CH y+ )] x + (x y)X - → [(CH y+ )X y -] x
w he re X - = I -, Br -…
X - → dopa nt c ount e r a nion
y: ra t io bt n. dopa nt ion a nd polym e r re pe a t ing unit
→ doping le ve l
● n-doping proc e ss
- e x posure t o re duc ing a ge nt (M )
- form a t ion of ne ga t ive ly c ha rge d polym e r c om ple x &
ox ida t ion of M
(CH ) x + (x y)e - → [(CH y-)] x
(x y)M → (x y)M + + (x y)e w it h t ot a l re a c t ion
(CH ) x + (x y)M → [(CH y-)] x + (x y)M + → [M y +(CH y-)] x
w he re M + = N a + , Li + … → dopa nt c ount e r c a t ion
● H e t e roc yc lic polym e rs
• polypyrrole & polyt hiophe ne
● Polya c e t yle ne
• de ge ne ra t e ground st a t e ; t w o ge om e t ric st ruc t ure s wit h
sa m e e ne rgy a nd diffe re nt se que nc e single -double bonds
● Polya niline
• pre pa re d e le c t roc he m ic a lly, by ox ida t ion of a niline in a c id
m e dia
• doping → not induc e c ha nge s in t he num be r of e le c t rons
a ssoc ia t e d w it h t he polym e r c ha in, but re la t e d t o a highly
sym m e t ric a l π- de loc a lize d st ruc t ure
• c onduc t ivit y vs. T ; polym e r ~ SC
M e c ha nism of doping proc e sse s
• “doping”: sa m e t e rm inology w it h inorga nic se m ic onduc t or, but t he
doping proc e sse s of c onduc t ing polym e rs a re quit e diffe re nt from
t hose of inorga nic se m ic onduc t ors
● Se m ic onduc t or: rigid la t t ic e , doping is w e ll de sc ribe d by ba nd m ode ls
→ doping proc e sse s; int roduc t ion of im purit ie s int o t he c ryst a l la t t ic e
w it h t he int e rga p e ne rgy le ve ls ne a r CB or V B; c onduc t ion proc e e ds
via a c ohe re nt propa ga t ion of e le c t rons a nd/or hole s a c ross t he la t t ic e
● Polym e r: fle x ible c ha ins, fa vor loc a lize d c ha in de form a t ion → im purit ie s
or doping a ge nt s do not be c om e pa rt of t he st ruc t ure , ra t he r a re
inse rt e d w it hin t he polym e r c ha in & c a n be e a sily re m ove d by a pplying
a n opposit e e le c t ric a l driving forc e ; doping proc e ss a re re ve rsible ; t he
spinle ss bipola ronsor solit ons t ra nsport t he c urre nt
M e c ha nism of doping proc e sse s
● T w o c ont ribut ions
- I nt ra c ha in t ra nsport : a ve ra ge c onjuga t ion le ngt h of c ha ins
- I nt e rc ha in t ra nsport : re gula rit y of polym e r st ruc t ure
(∵c onduc t ivit y inc re a se s by orde ring of st ruc t ure )
● M e t hods for m onit oring t he doping proc e sse s
- Opt ic a l a bsorpt ion: int e rga p t ra nsit ion c ha nge s a bsorpt ion
- in sit u spe c t roe le c t roc he m ic a l c e ll m e a sure m e nt
- M ic roba la nc e (QCM , qua rt z c ryst a l )
- Cyc lic volt a m m e t ry & a .c . im pe da nc e
e .g., CV of (CH ) x in LiClO 4 -PC:
a nodic (doping) & c a t hodic (undoping) pe a k s
→ re ve rsible proc e ss, t w o st ruc t ura l sit e s, long t a il: diffusion
c ont rolle d k ine t ic s
Applic a t ion of polym e r e le c t rode
● Ba t t e rie s ; lit hium /polypyrrole ba t t e rie s
Li / LiClO 4 -PC / (C 4 H 5 N ) v
Cha ra c t e rize d by t he follow ing e le c t roc he m ic a l proc e ss:
c ha rge
(C 4 H 5 N ) v + (x y)LiClO 4
disc ha rge
(C 4 H 5 N 3 + )(ClO 4 -) x y ] v +(x y)Li
● Opt ic a l displa y (e le c t roc hrom ic de vic e )
Li / LI ClO 4 -PC / [C 5 H 7 S]v , I T O, gla ss
Displa y is a ba t t e ry w it h a c olor c ha nge .
Ele c t ro-c he m ic a l proc e ss:
doping
[C 5 H 7 S] v + (x y)LiClO 4
(re d)
undoping
[(C 5 H 7 S 7 + )(ClO 4 -) x y ] v + (x y)Li
(blue )