1996 Fabrication and Characterization of Silver-based Solid-state Primary Batteries

7/29/2019 1996 Fabrication and Characterization of Silver-based Solid-state Primary Batteries

1/5

E L S E V I E R J ournal o f PowerSources62 (1996) 15-19

F a b r i c a t i o n a n d c h a r a c t e r iz a t io n o f s i lv e r - b a s e d s o l id - s ta t e p r i m a r yb a t t e r i e s

M. Venkateswarlu a, N. Satyanarayana b.."Department o f Physics. Osmania University. Hyderabad500 007. Indiab Departmentof P hysics. Pondicherry University.R.V. N agar. Pondicherry605 014. India

Received8 D ecember1995; accepted29 January 1996

A b s t r a c tSolid-state prim ary batteries are fabrica ted using the highe st cor~ductingcomposi tion o f Agl -Ag 20-(SeO2 + V2Os) (SS V) quarternaryglassy comp3und w ith different cathode materials such as I:C, (I + C):S E, and [ (I + C ) + SE] :TA_AI= 9: ! (!: iodide; C: graphite; SE: solidelectrolyte; "~A_AI: etraalkyl am mo nium iodide, and A_: me thyl, ethyl and b uty l). V arious sets of b aueries are fabrica ted with the follow ingconfiguration: anode/glassy solid electrolyte/cathode. The performance of the batteries made up of S SV glass is evaluated in terms of themeasured o pen-circuit voltage, polarization and discharge characteristics.

Keywords: Solid-state atteriesand characteristics;Glass.Silver

1 . I n t r o d u c t i o nT h e i m p o r t a n c e o f s o l i d - s t a te b a t t e ri e s ( S S B s ) h a s b e e ni n c r e a si n g c o n s i d e r a b l y d u e t o t h e i r a p p l i c at i o n a s n e w e l e c -

t r i ca l p o w e r s o u r c e s f o r a d v a n c e d t e c h n o l o g i c a l d e v i c es s u c has ca lcu la to rs , wa tches , cam eras , meas ur ing me te rs , com put -e rs , b io -m edica l dev ices , s pace , mi l i t a ry equ ipm ent , e tc . [ 1 -3 ] . F u r t h e r , b a tt e r i e s m a d e w i t h s o l i d e l e c tr o l y t e s ( S E s ) w i l lo v e r c o m e t h e m a n y l i m i t a ti o n s o f t h e c o n v e n t io n a l l iq u i d -e l e c t r o l y te b a t t e r i e s ( L E B s ) s u c h a s l e a k a g e , c o r r o s io n ,ins tab i l i ty towa rds t em pera tu re va r i a t ion , s hor t s he l f - l ife [ 1 -3 ] . I n v i e w o f t h e s e a d v a n t a g e s , v a r i o u s t y p e s o f S E s h a v eb e e n s y n t h e s i z e d [ 4 , 5 ] t o a c h i e v e h i g h i o n i c c o n d u c t i v i tyc o m p a r a b l e w i t h t h a t o f t h e l i q u i d e l e c t ro l y t e s .

A m o n g t h e a v a i l a b l e S E s , s i l v e r -b a s e d S E s d i s p l a y h i g hi o n i c c o n d u c t i v i t y a n d m o r e s t a b i li t y to w a r d s t e m p e r a tu r e .H e n c e , w e h a v e c h o s e n t h e s i l v e r se l e n o v a n a d a te ( S S V )g l a s s y s y s te m a n d s t u d i e d i ts t r a n sp o r t p ro p e r t i e s o d e t e r m i n et h e h i g h e s t c o n d u c t i n g c o m p o s i t i o n o f t h e S S V g l a s s y s y st e mf o r S S B a p p l i c a t i o n s [ 6 , 7 ] . R e c e n t l y , i t h a s b e e n f o u n d [ 5 , 8 -10] tha t the SSB cha rac te r i s t i c pa ram e te rs a re ve ry s ens i t ivet o t h e c h e m i c a l c o m p o s i t i o n o f t h e c a t h o d e m a t e ri a l. H e n c e ,in th i s pape r , we repor t the des ign , fab r i ca t ion and cha rac te r -i za t ion o f s o l id -s t a t e p r imary ba t t e r i e s us ing the h ighes t con-duc t ing SSV g la s s wi th d i f fe ren t ca thode ma te r i a l s . T hep e r f o r m a n c e o f S S B s i s a n a ly s e d i n t e r m s o f t h e m e a s u r e d

* Correspondingauthor.0378-7753/96/$15.00 1996ElsevierScienceS.A.All fights eservedP I I S 0 3 7 8 - 7 7 5 3 ( 9 6 ) 0 2 3 9 2 - 0

o p e n - c i r c u i t v o l t a g e ( O C V ) , p o l a r i z a ti o n an d d i s c h a r g echa rac te r i s t i c s .

2 . E x p e r i m e n t a l2 .1 . P r e p a r a t i o n a n d c h a r a c t e r i z a t i o n o f b a t te r y m a t e r i a l

A n a l a r g r a d e A g I , A g 2 0 , S e O 2 a n d V 2 0 5 c h e m i c a l s a r ec h o s e n t o p r e p a r e t h e f o l l o w i n g h i g h e s t c o n d u c t i n g 6 6 .6 7 %A g I - 2 3 . 0 7 % A g 2 0 - I 0 . 2 6 % [ 0 .8 S E O2 + 0 . 2 V 2 0 5 ] c o m p o s i -t i o n o f S S V g l a s s y s y s te m o b t a i n e d f r o m o u r e a r l i e r s t u d ie s[ 6 , 7 ] .A c c o r d i n g t o t h e m o l e c u l a r w e i g h t p e r c e n ta g e s , a p p r o p r i -a t e q u a n t i ti e s o f c h e m i c a l s a r e p l a c e d i n a q u a r t z c r u c i b l e a n dm e l t e d a t 5 5 0 C . T h e m o l t e n l i q u i d i s q u e n c h e d i n t o l i q u i dn i t r o g e n t o f o r m t h e g l a s s . T h e r e s u l ti n g b u l k c o m p o u n d i s, ,- round in to f ine pow der an d th i s i s us e d fo r cha rac te r i za t iona n d b a t t e r y st u d i es . T h e S S V c o m p o u n d i s e x a m i n e d b y X -r a y d ; f f r a ct i o n ( X R D ) . I t s g l a ss y n a tu r e i s c o n f ir m e d b y t h eo b s e r v e d p e a k - f r e e X R D s p e c tr u m . T h e v a r i o u s tr a n sl x w tp a r a m e t e r s o f t h e h i g h e s t c o n d u c t in g c o m p o s i t i o n o f t h e S S Vglas s , ob ta ined f rom our ea r l i e r s tud ie s , a re l i s t ed in T ab le 1 .2 .2 . Des ig n a n d f a b r i ca t i o n o f so l i -s :~ t e p r im a ry b a t t er i es

T h e h i g h e s t co n d u c t i n g c o m p o s i t i o n o f t h e S S V g l a s s yma te r i a l i s us ed a s SE fo r the fab r i ca t ion o f s o l id -s t a t ep r i m a r y


2/5

16 M. Venkateswarlu, N. Satyanarayana /Journal of Power Sources 62 (1996) 15-19Table IHighest conducting omposition nd transportparameters of SSV g lassysystemsHigh conducting ompositionof SSV glass aConductivity t 30 C (S/cm ) Activation nergy (eV) Heat of transport,q* (eV) Ion transportnumber ti)2.63 10 -2 0.22 0.23 = ! (0.9999) ssv: 66 67%Agl-23.07%Ag20-10.26%(0.8SeO2+ 0.2 V 205).b a t t e r ie s . I t i s o b se rv e d t h a t t h e b a t t e ry p e r fo rm a n c e i s v e rys e n s i t iv e t o t h e c h e m i c a l c o m p o s i t i o n o f t h e c o n s t i t u e n t s o ft h e c a th o d e m a t e r ia l [ 8 - 1 0 ] . H e n c e , v a r i o u s s e ts o f s o l id -s t a t e p r im a ry b a t t e r i e s h a v e b e e n f a b r i c a t e d u s in g $ SV g l a ssyc o m p o u n d s w i t h d i f f e r e n t c a t h o d e c o m p o s i t io n s .

Th e fo l l o w in g so l i d - s t a t e p r im a ry b a t t e r i es , w i th d i f f e re n tc a t h o d e c o m p o s i t i o n s , h a v e b e e n f a b r ic a t ed a n d s t u d i e d s ys -t e m a t i c a l l y i n o rd e r t o e s t im a te t h e p e r fo rm a n c e o f t h e c e l lsa n o d e ( A g + S E ) / s o l i d e l e ct r ol y te ( S S V ) / c a t h o d e

{ [ ( I +C ) + S E] + TA _ AI}w h e r e A g i s s i l v e r p o w d e r , S E t h e S S V s o l i d e l e ct r o ly t e , Ii o d id e , C g ra p h i t e , a n d TA _ A I t e t r a a lk y l a m m o n iu m io d id e( A = m e t h y l , e t h y l a n d b u t y l ) . A c c o r d i n g t o t h is b a t t er y c o n -f i g u r a t i o n , a n a l a r g r a d e s i l v e r p o w d e r a n d t h e S S V g l a s sm ix e r ( 1 :1 w e ig h t r a t i o ) a re u se d a s a a n o d e , Th e SE i s a d d e dto t h e s i l v e r p o w d e r t o im p ro v e t h e i n t e r f a c ia l c o n t a c t s . D i f -f e r e n t c o m p o s i t i o n s o f t h e c at h o d e c o m p o u n d s a r e m a d e b yv a ry in g t h e w e ig h t r a t i o s o f t h e i o d id e , g ra p h i t e , SE a n d

6 5 4

+ \!

Fig. l. (a) Cross-sectional iew of solid-stateprimarybatterywithebonitematerial: ( I ) ebo nitesheets, (2) copper eads: (3) bolts and screws: (4)resin. (5) graphite sheets; (6) cathode pellet: (7) anod e: (8) electrolyte.(b) Dischargeprocess of silver-ion onducting, olid-state lectrolytecell:( ! ) anodeand electrolyte nterface;(2) silver-ion onducting lectrolyte;(3) cathode and eiectmlyte nterface.

TA A I . A d d i t i o n o f g ra p h i t e t o t h e i o d in e i n c re a se s th e e l e c -t ro n i c c o n d u c t iv i t y a n d , h e n c e , i t a c t s a s a g o o d c u r re n t -c o l l e c to r . Th e a d d i t i o n o f SE im p ro v e s t h e i n t c r f a c i a lp r o p e rt i es a n d t h e a d d e d T A A I w i l l r ea c t w i t h A g I a n d f o r ma b e t te r c o n d u c t i n g l a y e r o r c o m p o u n d t o r e d u c e t h e a c t i v i tyo f t h e i o d i d e a t th e i n t e r f ac e [ 5 , 8 - 1 0 ] .

U s in g t h e a b o v e d e s ig n , t h e so l i d - s t a t e p r im a ry b a t t e r i e sw e r e c o n s t r u c t e d i n t h e f o l l o w i n g . T h e f i n e ly g r o u n d p o w d e r so f t h e a n o d e m ix tu re a n d SSV e l e c t ro ly t e l a y e r s w e re p re sse da t a n o p t i m u m p r e s s u re o f 5 0 0 0 k ~ c m - 2 t o f o r m a p e l le t o f1 0 m m d i a m e t e r a n d a b o u t 1 .5 t o 2 . 0 m m i n t h ic k n e s s . A l s o ,f i n e l y g r o u n d p o w d e r o f t h e c a t h o d e m i x t u r e a l o n e w a sp r e s s e d to m a k e p e l l et s o f 1 0 - 1 2 m m d i a m e t e r a n d a b o u t 1m m i n t h ic k n e s s . T h e a n o d e / e l e c t r o l y t e / c a t h o d e p e l l e ts w e r esa n d w ic h e d b e tw e e n g ra p h i t e d i sc s , c o p p e r fo i l s w e re u se do v e r t h e tw o g ra p h i t e d i sc s , a s l e a d s , t o fo rm a so l i d - s t a t ep r im a ry b a t t e ry . Th e b a t t e ry a sse m b ly t o g e th e r w i th a n o u t e rj a c k e t m a d e u p o f e b o n i t e m a t e r ia l a r e s h o w n i n F i g . 1 a ) .Im m e d ia t e ly a f t e r f a b r i c a t i o n , a l l t h e b a t t e r i e s w e re se a l e dw i t h e p o x y r e s i n t o p r o v i d e i s o l a t i o n f r o m a t m o s p h e r i ce f fe c t s . Sy s t e m a t i c a l l y , v a r io u s se t s o f so l i d - s t a t e p r im a ryb a t t e r i e s w e re f a b r i c a t e d u s in g SS V g l a ss w i th d i f f e re n t c a th -o d e m i x t u re s . L a b o r a t o r y - s ca l e s t u d ie s w e r e m a d e o f t h e i rt e m p e r a tu r e d e p e n d e n c e o f t h e O C V , t h e p o l a r iz a t i o n a n dd i sc h a rg e c h a ra c t e r i s t ic s i n o rd e r t o e s t im a te t h e p e r fo rm a n c e6 i e a c h b a t t e ry . Th e t y p i c a l d i sc h a rg e p ro c e ss o f t h e s i lv e r -i o n c o n d u c t in g , so l i d - s t a t e e l e c t ro ly t e c e l l i s sh o w n inF i g . 1 ( b ) .

Th e fo l l o w in g set s o f b a t t e r ie s w e re c o n s t ru c t e d :( Ag + SE = !: I )/66SSV82 ( I:C batteries V 1(Ag +S E = I:1 ) 166SSV82/[ (! +C):SE ] batteries V2(Ag + SE= 1:!)/66SSV82/[(1 + C) + SE]:TMA!=9:1 ba t te ry 3(Ag + SE ~ 1:1)/66SSV82/[ I + C) + SE]:TEAI~9:1 battery V4(Ag + SE= !:1)/66SSV82/[ (I +C) + SE]:TBAI=9:1 battary V5

O n e se t o f b a t t e r ie s (V 1 ) h a v e b e e n f a b r i c a t e d w i th d i f-f e re n t w e ig h t r a t i o s o f i o d id e a n d g ra p h i t e ( I :C ) m ix tu re s a sth e c a th o d e m a te r i a l . F ro m s tu d i e s o f t h e b a t t e ry c h a ra c t er -i s t ic s , t h e b e s t c a th o d e c o m p o s i t i o n i s d e t e rm in e d fo r fu r th e rs t u d ie s . T h e S S V S E m a t e r i a l i s a d d e d i n v a r i o u s w e i g h t r a t i o sto t h e b e s t c a th o d e ( I :C) c o m p o s i t i o n a n d a se t o f so l i d - s t a tep r im a ry b a t t e r i e s (V 2 ) i s f a b r ic a t e d w i th d i f f e re n t( I + C ) : S E c a t ho d e c o m p o s i t i o n s . A g a i n , th e p e r f o r m a n c e o fb a t t e r i e s is e s t im a te d a n d t h e b e s t c a th o d e c o m p o s i t i o n , i .e .( I + C ) : S E , i s se l ec t ed . N e x t , 1 0 % o f t e tr a a lk y l ( m e t h y l ,e t h y l a n d b u t y l ) a m m o n i u m i o d i d e i s a d d e d t o t h e b e s t[ ( I + C ) + S E ] c a t h od e c o m p o s i t i o n to r e d u c e t h e i o d id e


3/5

M. Venkateswarlu, N. Satyanarayana /Journal of Power Sources6 2 (1996) 15-19 1 7

ac t iv i t i e s and the cor r espo nding se t s o f ba t te r ie s a r e f abr ica ted( V 3 t o V 5 ) .

3 . R e s u l t s a n d d i s c u s s i o n

3. I . Temperaturedependence o f open-circuit voltageThe f i rs t cha r ac te r i s t ic pa r amete r o f the b a t te r y i s the O CV .

T h e O C V w a s m e a s u r e d a t r o o m t e m p e r a t u r e f o r v a r i o u s( I + C ) c o m p o s i t i o n s o f t h e c at h o d e a n d w a s f o u n d t o b e 6 87m V f o r S S V g l a s s y S E . T h e m e a s u r e d O C V i s e q u a l t o th et h e r m o d y n a m i c a l l y c a l cu l a t e d t h e o r e t ic a l v o l t a g e . T h e t e m -p e r a t u re d e p e n d e n c e o f O C V w a s m e a s u r e d f o r v a r io u s c a t h -ode com pos i t ions , s ee F ig . 2 . For a s e t o f ba t te r ie s , the O CVi n c r e a se s w i t h t e m p e r a t u r e. T h e v a r i at i o n o f O C V w i t h t e m -p e r a t u re d e c r e a s e s p r o g r e s s i v e l y f o r c e l l s m a d e o f : ( I + C ) ,( I + C ) + S E a nd [ ( I + C ) + S E ] + ( T M A I / T E A I/ T B A I )ca thodes . I t i s f ound tha t the addi t ion o f C , SE , an d TA _A I othe iod ide s tab i l i zes the ce l l s to pr ovid e an un in te r r up tedcons tan t vo l tage sour ce in the te s ted 27 - 60 (2 temper a tur er ange .3.2. Polarization and discharge cbaracteristics of solid-state primary batteries

P o l a r i z a ti o n ( c e l l v o l t a g e v e r s u s c u r r en t d e n s i t y ) m e a s -u r e m e n t s w e r e m a d e f o r d i f fe r e n t ca t h o d e I : C c o m p o s i t i o n sby a pply in g d i f f e r en t loads , s ee F ig . 3 . The ce l l vo l tage f orI :C = 7 :3 d i sp lays be t te r pe r f or mance than the o the r I :C ca th-o d e c o m p o s i t i o n s . F o r a l l t h e I : C c a t h o d e c o m p o s i t io n s , th ec e l l s g i v e t h e s a m e O C V o f 6 8 7 m V ; t h i s i s eq u a l t o t h et h e o r e ti c a l v o l t a g e o f a n A g I - b a s e d c e l l ( 6 8 7 m V ) . A p a r t ic -u l a r lo a d ( c o r r e s p o n d i n g t o 1 0 0 / , t A c m - 2 ) i s a p p l ie d an da l low e d to d i scha r ge the ce l l s . F ig . 4 show s the r esu l t ingdischar ge ch ar ac te r i s t i c s o f ce l l s w i th d i f f e r en t I :C ca thodec o m p o s i t i o n s . T h e b a t t e ry m a d e u p o f S S V g l a s s y m a t e r i a l

8 0 0 - -

( 1 }

~ 1 2 l~ 7 0 0 - ( 3 )- - . ~ , v ( 4 )

~ 6 O O . l , C : ? : 3 C e l l ( l lI , C : S E : 7 : 3 C e I I |2 }[ ( It C } , S E ! : T M A 1 : 9 : 1 C e l l ( 3 )[ ( I , C ) * S E ] : T E A I : 9 : I C e l l ( 4 )( ( I ,C ) * S E ] : T E t A I = 9 : I C e ll ( 5 )

5 0 0 3 0 4 0 5 0 6 0 70T e m p e r a t u r e P C)

F ig . 2 . T em per a tu r e dependenc e o f open - c i r c u i t v o l t age o f c e l l s m ade up o fS S V g l a s s w i th v a r i o u s c a t h o d e m m e r i a ls I: C . ( I + C ) : S E a n d[ ( ! + C ) + S E ] : T A A I ( A = m e t h y l , e t h y l a n d b u t y l ) .

70 0

t :C:7:3 Ce~l 3)I :C=6:4 Cell (4)

30 0, ~ , , 0 3 , 0 2 ; + ' i t 0Current Oens i t y (mA/m 2}

F ig . 3 . P o la f i z a l i on c ha rac te~s l ic s o f c e l l s m ade up o f S S V g las s w i t hv an ousI :C com pos i t ions .w i t h a c a th o d e c o m p o s i t i o n o f I : C = 7 : 3 d i s p l a y s t h e b e s tshelf - l i fe .

T h e O C V f o r th e I : C c a t h o d e c o m p o s i t i o n i s f o u n d t o b e6 8 7 m V , w h i c h i s e q u a l t o th e t h e r m o d y n a m i c a l l yca lcu la tedt h e o r e ti c a l v o l t a g e ( 6 8 7 m V ) . F o r v a r i o u s c u rr e n t d e n s i ti e s ,a f a l l i n O C V o f u p t o 6 0 % o f i t s i n i t ia l v a l u e ( 6 8 7 m V ) i so b s e r ~ : d f o r a l l th e c a t h o d e c o m p o s i t i o n s . A s s h o w n i n F i g .3 , f o r such a f a l l in O CV , the cur r en t d r a in i s about 1 .2 to4 . 8 5 m A a n d t h e m ~ i m u m c u r r e n t d r a i n is o b t a i n e d f o r t h eb a t t e r y w i t h a n l : C = 7 : 3 c a t h o d e c o m p o s i t i o n . F r o m t h e d a mg i v e n i n F i g . 4, i t i s c l e a r ~ a t t h e b a t t e r y w i t h a 7 : 3 c a t h o d ec o m p o s i t i o n y i e l d s h e h i g h e r d i s c h a r g e c a p a c i t y a n d s p e ci f i ce n e r g y . T h e c a t h o d e p e l l e t i t h a 6 : 4 c o m p o s i t i o n i s f o u n dt o b e b r it t le , h i l e t h e p e l l e t s w i t h h i g h e r p e r c e n t a g e s o fg r a p h i t e e x h i b i t c r a c k s . H e n c e , t h e c a t h o d e p e l l e t w i t hI :C = 7 : 3 g i v e s t h e b e s t p e r fo r m a n c e a n d i t w a s s e l e c t e d fo rf ur the r s tud ies .A se t o f ba t te r ie s w er e f abr ica ted w i th d i f f e r en t ca thodec o m p o s i t i o n s ( ( I + C ) : S E ; S E = S S V g l a s s ) a n d t h e i r p o l a r -iza t ion and d i schar ge char ac te r i s t i c s w er e examined . Thepola r iza t ion char ac te r i s t ic s a r e g iven in F ig . 5 . Fo r a dr op inO C V o f u p t o 6 0 % o f t h e i n i ti a l v o l t a g e ( 6 8 7 m V ) , t h e c u r re n tdr a in i s about 5 mA . The d i schar ge char ac te r i s t i c s w i th ac u r r en t d e n s i t y o f 1 0 0 / z A c m - 2 a r c p r e s e n t e d i n F i g . 6 .

? 0 0 I :C:9: lCelt IS)! :C:8:2CMI (2 )

% ~ l : C=7 :3C . " ( 3 )60 0" ~%,k~ i :C:6:&Cel t (&)

50 0o>

400.

300 , 10 20 30 4,0 50 60 70 f lO 90 100T im e ( h )

F ig . 4 . D i s c h a r g e charac ter is t ics o f ce i ls made up of v a r i o u s c a t h o d e I : Cc o m p o s i t io n s ; l o a d ~ 1 0 0 / z A c m - 2 .


4/5

18 M. Venkateswarlu, N. Satyanarayana /Jour nal of Pow er Sources 62 (1996) 15-19700

~ 5 0 0 -

' , . ~3O 0 ( I *C ) : S E = 8 : 2 C e l l ( 2 )( l ,C) :SE=7:3 Cel l (3)( I . C ) : S E : 6 : 4 C e l t ( 4 )

Current Dens i ty (mA/cm 2)F i g . 5 . P o l a r i z a t i on c ha rac t er is t ic s o f c e l l s m ade o f S S V g l as s w i t h v a r i ousc a t h o d e ( ; + C ) : S E c o m p o s it io n s .

700

~ 6 o o .E

"_-~500"

[I'C}: SE 9:1 C211(1)[l'~C)SE=S :2 Cel l 2)( I ' ,OSE:7:3 Ce~ l (3)(4 )

LO 4O 6O SO 10GT i m e (h iFig. 6. Discharge characteristics of cells m ade up of various cathode(I +C ):SE compositions; oad= 100/~A cm -2.

B a t t e r i e s w i t h a ( I + C ) : S E = 7 : 3 c a t h o d e c o m p o s i t i o n g i v et h e b e st p e r f o r m a n c e w i t h a n e n e r g y d e n s i ty o f 3. 21 W h k g - t .T h e a d d i t i o n o f S E t o ( I + C ) r e d u c e s t h e r e s is t a n c e a t t h eTable 2

i n t e r f a c e . T h u s , t h e a d d i t i o n o f S E i m p r o v e s b o t h t h e d i s -c h a r g e c a p a c i t y a n d t h e e n e r g y d e n s i ty . F i n a l l y , a s e t o f b a t -t e r i e s w e r e m a d e w i t h d i f f e r e n t c a t h o d e c o m p o s i t i o n s{ [ ( I + C ) + S E ] : T A A I = 9 : l } . T h e c e l l p a r a m e t e r s m e a s u r e df o r a l l t h e b a t t e ri e s m a d e w i t h S S V g l a s s a n d d i f f e r e n t ca t h o d em a t e r i a l s a re s u m m a r i z e d i n T a b l e 2 .

T h e p o l a r i z a ti o n c h a r a c t e r i st i c s f o r t h e b a t t e r i e s m a d e w i t hd i f f e r e n t c a t h o d e c o m p o s i t i o n s a r e s h o w n i n F i g . 7 . T h e c u r -r e n t d r a i n o b t a i n e d f r o m t h e v a r i o u s b a t t e r i e s i s i m p r o v e dp r o g r es s i ve l y b y t h e a dd i t io n o f T M A I , T E A I a n d T B A I t ot h e c a th o d e . T h e c u r r e n t d r a i n f o r a d r o p i n v o l t a g e o f u p t o6 0 % o f t h e O C V f o r b a tt e r i es w i t h S S V g l a s s i s 8 .5 , 1 2 a n d1 8 m A , r e s p e c t i v e ly , f o r t h e c a t h o d e m a t e r i a l s T M A I , T E A Ia n d T B A I . I t i s f '~ u n d t h a t t h e a d d i t i o n o f T A A I t o t h e c a t h o d er e d u c e s t h e i o ~ l n e a c t i v i t y a t t h e e l e c t r o d e / e l e c t r o l y t e i n t e r-f a c e [ 5 , 8 - 1 0 ] . A t t h e i n te r f ac e , t h e T A M r e d u c e s th e i o d in ea c t i v i t y b y f o r m i n g a s tr o n g c o m p l e x ( C H 3 ) 4 N I , w h i c ha v o i d s t h e t a r n i s h i n g a c t i o n s o f m o l e c u l a r i o d i n e w i t ht h e e l e c t r o l y t e a n d , h e n c e , i n c r e a s es t h e s p e c i f i c e n e r g y .A l s o , t h e i o n i c c o n d u c t i v i t y o f t h e r e a c t i o n p r o d u c t[ ( C H 3 ) 4 N ] 2 A g t 3 I t 5 i s h i g h l y c o n d u c t i n g a n d o f f e r s g o o dc h a r g e - t r a n s fe r c o n ti n u i t y [ 5 ] . H e n c e , t h e im p r o v e m e n t i np o la r i z a t io n c h a ra c te r i s t i c s o f t h e s e c e l l s i s a t t r i b u te d tore d u c e d in t e rn a l r e s i s t a n c e ( I R ) d r o p ( e v e n a t h i g h e r c u r re n td e n s i t i e s ) c o m p a r e d w i t h c e l l s o f ( I + C + S E ) c a t h o d e s .T h i s i s d u e t o t h e f o r m a t i o n o f a c o m p l e x w i t h h i g h e rc o n d u c t i v i t y t h a n A g I [ 5 ] .

T h e d i s c h a r g e c h a r a c t e r i s t i c s a t a c u r r e n t d e n s i t y o f 1 0 0~ A c m - 2 f o r b at te r ie s w i t h d i f f e re n t c a th o d e c o m p o s i t i o n sa r e s h o w n i n F i g . 8 . T h e s e b a t t e r i e s d i s p l a y b e t t e r d i s c h a r g ec a p a c i t i e s t h a n th e o th e r c e l l s , c f . , F ig s . 4 a n d 6 . T a k in gi n t o c o n si d e r a t i o n a l l t h e c e l l p a r a m e t e r s ( s u m m a r i z e d i nT a b l e 2 ) , t h e b a t t e r i e s m a d e o f [ ( I + C ) + S E ] : T A A I ;A = m e t h y l , e t h y l a n d b u t y l) c a t ho d e c o m p o s i t io n s e x hi b i tb e t t e r d i s c h a r g e p e r f o r m a n c e .

Cell parameters measured at room emperature (303 K for batteries made up of SSV glassy electrolytecompound a studied with differentcathode m aterialsCathode composition OCV Current drain Discharge ime Discharge capacity Specificenergy(mV) (mA) (h ) (mAh) (Whkg - t )a) I:C variation9: I 687 1.20 34 2.67 I. ! 88:2 687 2.62 43 3 .37 1.567:3 687 4.85 75 5.89 2.62

6:4 686 3.21 57 4A8 1.98b) ( I + C ) : S E9: i 687 1.16 33 2.59 1.158:2 687 2.82 48 3.77 1.677:3 687 8.20 92 7.22 3.2 !6:4 684 3.60 65 5.10 2.26c ) [ ( I + C ) + S E ] : T A A I = 9 : !TM AI 676 8.50 122 9.58 4.29TE Al 663 12.0 98 7.69 3A0TB A! 652 18.0 68 5.34 2.32a 66.67% A gl-23.07%Ag~O -10.26%(0.8 SeO2+ 0.2 V2Os). I: iodide, C: graphite, SE: solid electml~e, T AAI=tetranlkylammonium iodide (A = methyl,ethyl and butyl).


5/5

M. Venkateswarluo N. Satyanarayana I Journal of Power Sources 62 (1996) 15-19 19

S l ~ ( ' ) 1> I ~ \ \ - ( 3 ) I

1 6 s ) , i 3 ) a 1 ~ 0Curee~ t Dens i t y (mA/cm )

F i g . 7 . P o l a r i z a t i o n c h a r a c t e ri s t ic s o f c e l ls m a d e o f S S V g l a s s w i t h v a r i o u sc a t h o d e [ ( I + C ) + S E ] : T A A I ( A = m e t h y l , e t h y l a n d b u t y l ) c o m p o s i t io n s .

6 0 0~ 5 0 0

4 0 0

30 0

(( I~.C +SE~'.'TMAI=9:I C~4i(1)(( I+C)+$g):TEJO=9: I Cel l (2 ]( ( I , C ) + S E ) :BAI=9: I Cel l (3 ]

i s s 'o 7 "s t oo ~ :~s t sT i m e ( h )Fig. 8. Discharge characteristics of cel ls mad e of various cathode[ (I + C ) + SE] :TAAI A = methyl, ethyl and butyl) compositions.4 . C o n c l u s i o n s

T h e g l a s s y n a t u r e o f t h e h i g h e s t c o n d u c t i n g c o m p o s i t i o no f t h e S S V c o m p o u n d p r e p a r e d b y t h e m e l t - q u e n c h i n gm e t h o d i s c o n f i r m e d b y X R D a n a l y s i s . T h e c o m p o u n d i sc h o s e n a s t h e S E m a t e r i a l f o r t h e f a b r ic a t i o n o f S S B s . T h ep r i m a r y c e l l s a r e f a b ri c a t ed u s i n g t h e S S V g l a s s w i t h v a r y i n gc a t h o d e c o m p o s i t i o n s . A h i g h O C V o f a ro u n d 6 8 7 m V i so b t a i n e d f o r c e l l s m a d e u p o f S S V g l a s s y m a t e r i a l , w h i c hs u g g e s t s t h a t t h e f a b r i c a t e d b a t t e r i e s a re s u i t a b le fo r e l e c t ro -

c h e m i c a l a p p l i c a ti n n s . T h e b a t t er y p e r f o r m a n c e i s v e r y s e n -s i t i v e t o t h e c o m p o s i t i o n o f t h e c a t h o d e a n d t h e p r e s e n t s t u d ya s s i s t s t h e c h o i c e o f t h e b e s t c o m p o s i t i o n f o r t h e c a t h o d ec o n s t it u e n ts . A s e t o f b a t t e r ie s h a s p r o v i d e d c u r r e n t d r a i n s o fa b o u t 1 . 2 - 8 . 2 m A a n d s p e c i fi c e n e r g i e s o f a b o u t 1 . 1 - 3 . 2 W hk g - ) . T h e s t a bi l it y o f t h e s e c e l l s i s i m p r o v e d a p p r e c i a b l y b yth e a d d i t io n o f T A_ A I o th e c a th o d e . F u r th e r , t h e p o la r i z a t io nc h a r a c te r i s ti c s o f t h e s e c e l l s a r e a l s o i m p r o v e d b y t h e a d d i t i o no f T A A I t o th e c a th o d e s . A s e t o f S S B s e x h i b i t O C V ~ b e t w e e n6 7 6 a n d 6 5 2 m V , c u rr e n t d r a in s o f 8 . 5 - 1 8 m A , a n d s p e c i f i ce n e r g i e s b e t w e e n 2 . 3 a n d 4 .2 9 W h k g - 1. T h e s e zesalts s u g -g e s t m , , t c e l l s f a b ri c a te d w i t h S S V g l a s s y m a t e r i a l a s S E a r es u i t ab l e f o r l o w - p o w e r , i o n i c d e v i c e a p p l i c a ti o n s t h a t r e q u i r elo n g s h e l f - l i v e s .

A c k n o w l e d g e m e n t sO n e o f th e a u t h o rs ( N . S . ) i s g r a t e f u l t o D e p a r t m e n t o f

S c i e n c e a n d T e c h n o l o g y , G o v e r n m e n t o f I n d i a , f o r f i n a n c ia ls u p p or t i n t h e f o r m o f r e s ea r c h p lo j e c t ( S P / S 2 / M - 5 7 / 9 0 ) .

R e f e r e n c e s[I] D. Linden (ed.), llandbook of Batteries and F~el Celh, McGrawHill, New York , 1984.[2] C.A.C. Sequeda and A. Hooper (eds.) Solid St~lte Batteries. NATO

Advanced Study Institute Series, Maninus Nijhof,DordrecM, 1935.[3] R.T. Foley,J. Electrochem. SOc., 116 (1969) 13.[4 ] C .C. Liang,Appl. Solid State Sci., 116 ( 1969 95.[5 ] B .B. Owens,Adv. Electrochem. Electrochem. Eng., 8 (19/ ! ) 1.16l M. Venkateswarlu and N . Satyanarayana, Radiat. Effects DefectsSolids, submitted for publication.[71 M. Venkateswadu, K. Narasimha Redd y and N. Satyanara~ana, SOI~d

State Ionics, (1996) in press.[8] P.S.S . Prasad and S. Radhakrishana, J. Powersources, 25 (1989) 287.[9] A. Karthikeyan and N. Satyanarayana,J. Power So~,ces, 51 (1994)457.[ 10] M . Venkateswarlu and N . Satyanarayana,Solid State Ionics, (1996)in press.

Documents

1996 Fabrication and Characterization of Silver-based Solid-state Primary Batteries