inorganic ion exchange membrane fuel cell...nasa cr-54379 report sm-46221-43 gpo price $ 6ts...

NASA CR-54379 REPORT SM-46221-43

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INORGANIC ION EXCHANGE MEMBRANE FUEL CELL

PERIOD ENDING 10 APRIL 1965

I

i

I I

i prepared for

NATIONAL AERONAUTlCS AN9 SPACE ADMlNlSTRATlQN

CONTRACT NAS 3-6000

A S T R O P O W E R L A B 0 R A T 0 R Y 2121 CAMPUS DRIVE e NEWPORT BEACH, CALIFORNIA

M I S S I L E 8c S P A C E SYSTEMS DIVISION D O U G L A S A I R C R A F T C O M P A N Y . I N C . -*\‘.-I ” ‘ ( - \ I C 3 C . \ L = p s \ l - \

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NOTICE

This report was prepared as an accountof Government sponsored work. Neither the United States, nor the National Aeronautics and Space Administration (NASA), nor any person acting on behalf of NASA:

A.

B.

Makes anywarranty o r representation, expressed o r implied, with respect to the accuracy, completeness, o r usefulness of the information contained in this repor t , o r that the use of any information, apparatus , method, or process disclosed in this report may not infringe privately owned r ights ; o r

Assumes any liabilities with respec t to the use of , o r for damages resulting f rom the use of any informal:ion, appa r - atus, method o r process disclosed in this repor t .

As used above, "person acting on behalf of NASA" includes any employee o r contractor of NASA, o r employee of such contractor , to the extent that such employee o r contractor of NASA, o r employee of such contractor prepares , disseminates , o r provides a c c e s s to, any information pursuant to his employment o r contract with NASA,

=r his employment with such contractor .

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I I I I I I I I I I I I I I I I I I I

QUARTERLY PROGRESS R E P O R T SM-46221 -Q3

INORGANIC ION EXCHANGE MEMBRANE FUEL C E L L

by C . B e r g e r and M. P . S t r i e r

G . B e l f o r t

p r e p a r e d f o r NATIONAL AERONAUTICS AND S P A C E ADMINISTRATION

A p r i l 1965

CONTF,ACT N A S 3-6000

Technic a1 Manag errient NASA L e w i s R e s e a r c h C e n t e r

S o l a r and C h e m i c a l Power B r a n c h Cleveland, Ohio

Danie l G . S o l t i s

MISSILE & S P A C E SYSTEMS DIVISION ASTROPOWER LABORATORY

Douglas A i r c r a f t Company, Inc. N e w p o r t B e a c h , California

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I I I I I I I I I I I I I I I I I

C TABLE OF CONTENTS

1 . 0 SUMMARY AND CONCLUSIONS

2 . 0 INTRODUCTION

3 . 0 EXPERIMENTAL PROCEDURE, RESULTS AND DISCUSSION

3. 1 Fuel Cell T e s t s

3. 1.1 3. 1 . 2

Standard Fue l Cell T e s t s Compact Fuel Cell Life Tes t s

3 . 2 Catalyst-Membrane and Electrode-Catalyst- Membrane

3. 3 Prepara t ions by P res s ing and Sintering Techniques Mass and Heat T rans fe r Analysis of Optimum Fuel Cel l Design P a r a m e t e r s

3. 3 . 1 Mass Trans fe r Analysis 3. 3 . 2 Heat T r a n s f e r Analysis

Additional Studies - New Catalyst and Water- Proofing Studies

3 . 4

4 . 0 FUTURE WORK

5.0 RE FE RENC ES

6 . 0 PROJECT PERSONNEL

S M- 4622 1 - Q3

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Figure

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LIST OF ILLUSTRATIONS

Fuel Cell Membrane - Catalyst Composite

Log Resistivity Versus Percent Relative Humidity fo r the C200B Membrane a t 7OoC, 9OoC, and 105OC

New Astropower Fuel Cell

Compact Fuel Cel l in an Oven During Operation

F r o m Left to Right, 3 Types of Back-up P la t e s Used in T e s t s 6, 7 and 8 Respectively

Relationship of Areas of Three Different Types of Back-up Pla tes Used in the Compact Fuel Cell Design

Synopsis of Fue l Cell Life Tes t at 65i l0C, A s t ropowe r Zirconium Phosphate- Z eolon- H Membrane Voltage vs T i m e at Current Density of 30 rna /cm2

Synopsis of Life Tes t s a t 6 6 2 Z°C, Tes t 13, Table I Voltage v s Time at Current Density of 30 ma/cm2

Polarization Curves fo r Inorganic Membrane Fuel Cel l , Tes t 5 , Table I

Polar izat ion Curves fo r Inorganic Membrane Fuel Cell , Tes t 8, Table I

Polar izat ion Curves for Inorganic Membrane Fuel Cel l , Tes t 13, Table I

Polarization Curves f o r Inorganic Membrane Fuel Cel l , T e s t 14, Table I

Polarization Curves fo r Inorganic Membrane Tes t Cel l , T e s t 19, Table I

SM- 462 2 1 - Q3

Discharge Gas Humidity vs Fuel Cell Geometry

Optimized Fuel Cell Design

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I I I I I I I I I I I I I

1.0 SUMMARY AND CONCLUSIONS

The most significant accomplishments during this , the third quarter ly

report period, a r e the establishment of a fuel ce l l operational capability at

t empera tures as high as 148OC and performance levels in the range of

50 m a / c m

a t 300 hours of continuous operation a t essentially the s a m e level of voltage and

current . Fuel ce l l studies were performed in both the old Astropower fuel ce l l

and a newly optimized compact unit, the design of which was based on pract ical

experience as well a s heat and m a s s t ransfer considerations.

2 2 a t 0.65 volts and 0. 72 volts a t 30 m a / c m . This performance held

The following resul ts were specifically obtained:

(1) Membrane thickness had l i t t le if any effect on fuel cel l p e r -

formance up to about thickness levels M 0. 75 mm for the

specific ce l l configuration employed.

Fuel ce l l performance is relatively independent of tempera-

t u r e over the temperature interval of 65OC - 12OoC. Steady

performance is obtained a t t empera tures above and below this

range a t somewhat lower levels. An explanation for the con-

stancy of fuel ce l l performance in the 65O - 12OoC range is

that membrane resist ivity remains constant over this temper--

t u r e range. This is borne out by recent independent laboratory

measurements of the resis t ivi ty-relat ive humidity-temperature

(2)

relationships for such membrane sys tems (2) . (3) Impregnation of platinum black into the membrane s t ruc tu re

by a sintering technique is conducive to the stabil i ty of fuel

ce l l performance. If the depth of impregnation of the plati-

num black i s reduced to 10% of the overal l membrane thick-

nes s , enhanced performance resu l t s .

Palladium is as effective as platinum in promoting fuel ce l l

performance.

Increasing the concentration of impregnated platinum black

beyond 20% does not appear to affect performance.

(4)

(5)

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C I I I I I I I I I I I I

( 6 ) Increase of gas exposed a r e a s of the wafer backup plate in

the compact fuel cell t es t s enhances fuel cel l performance.

The highest performance of the program to date was achieved

in this manner.

(7) The relationships in ( 1 ) - (5) a r e essentially similar to those

fo r the previously employed nonoptimized fuel cell .

The cur ren t and future programs concerned with attempted improve-

ment of membrance-catalyst and membrane-catalyst -electrode configurations

a r e presented. Waterproofing and water removal by wicking a r e now in prog-

r e s s a s well.

At this point it appears that enhancement of performance to the 0 .75 volt

and 50 ma /cm ' level is in the offing f o r the Astropower zirconium phosphate-

"Zeolon €3" membrane fuel ce l l without any membrane reformulation.

2

I, I I I I I I I I I I I I I I I I I I

2.0 INTRODUCTION

By the mid-point of this program, it was evident that the original 2 ta rge t performance established for this program of 25 - 50 m a / c m

0 . 5 v. fo r 300 hours could b e met by the use of zirconia-phosphoric acid-

"Zeolon €3" membranes having t r ansve r se strengths of 5 , 0 0 0 ps i o r grea te r .

a t

Then, it was decided to attempt to enhance the performance by optimization

of the fuel ce l l design a s well as the membrane-catalyst-electrode configura-

tion while keeping the membrane composition constant.

res t r ic t ion on fuel ce l l operational temperature , it became important to

determine the tempera ture for optimum performance.

Since t h e r e was no

During this report period, it was possible to achieve a 60% improve-

ment in fuel ce l l performance b y two independent approaches.

approach, a compact fuel ce l l was designed on the bas i s of prac t ica l operating

conditions and substantiated by heat and m a s s t ransfer analysis.

approach, various exploratory t e s t s had suggested the design of a membrane-

catalyst configuration wherein the catalyst was impregnated in the membrane

to only a very small depth.

In the f i r s t

In the second

Simultaneously, it has been established that hydrogen-oxygen fuel

ce l l s can b e operated a t t empera tures as high a s 148OC.

not appear to have a significant effect on fuel ce l l performance in the 6 5 O - 12OoC

range because the conductivity of the membrane remains essentially invariant

with increasing tempera ture under these conditions.

a r e given in this repor t as well a s indications that s t i l l higher performance

Tempera ture does

The details of these studies

levels could b e attained.

0 . 7 volts was set .

A new performance target level of 50 m a / c m L a t

3

3 . 0 EXPERIMENTAL PROCEDURE, RESULTS AND DISCUSSION

3 . 1 Fue1,Cell Tes ts

Fuel cell testing w a s intensified in efforts to establish the param-

e t e r s f o r optimum fuel cell performance,

tes t s (23) performed during this report per iod a r e compiled in Table I in o rde r

of increasing t e s t temperatures .

density of 30 m a / c m

the s tandard Astropower fuel cel l described in References (1) and (2). The

second type was an optimized compact fuel cell described in References (3)

and (4).

The resul ts of the most significant

All tes ts were performed at a constant cur ren t 2 Two types of test ce l l s were used. The first type was

The resu l t s obtained will now be discussed.

3. 1, 1 Standard Fuel Cell Tes t s

All t e s t s were performed at constant cur ren t density of 2 30 m a / c m

relative influences of tempera ture and membrane thickness on fuel cell

performance.

In all instances, the experimental conditions were standard, a s descr ibed in

References (1) and (210

thickness levels within the 0.2 - 0,75 m m range have l i t t le o r no bearing on

fuel cell performance except possibly for fuel cell longevity. The resu l t s of

Tes t (18) a r e comparable to those of Tes ts (2) and ( 3 ) , demonstrating that

performance over the temperature interval of 65 to 100°C i s unaffected by

tempera ture .

shows that poorer performanee i s related to increased fuel cell resistance.

It i s our belief that the higher fuel cell res i s tance a t 25OC i s due to inadequate

water product removal through lower vaporization occurring at that t empera ture .

Appropriate water proofing will probably c o r r e c t this problem,

Tes t (1) was performed at 25OC in o r d e r to help establish the

T e s t s (2) and (3) and (18) a r e in the same category as well.

The resul ts at 65OC (Tes t s 2 and 31) indicate that

Howevever, the lower performance at 25OC (Test 1) definitely

Tes t (4) was conducted with a membrane which had

platinum deposited on it by a chemical procedure involving the reduction of

chloroplatinic acid.

without platinum deposited on the membrane.

The performance level was no better than that of Tes t (2)

Tes t (5) was initiated during the previous quar te r and

mentioned in Reference (2). It had been observed in previous hydrolysis

4

I I I I I I I I I I I I I I I I I I

studies that this membrane lost 5. 5% of its total weight through re lease of

unincorporated phosphoric acid upon being i m m e r s e d in distilled water a t

75OC for two hours. Some evidence had indicated the possibility of small

gradual l o s ses in phosphoric acid f rom the membrane during actual fuel cel l

operation.

affected fuel cell performance.

which had been soaked f o r two hours at 75OC followed by a drying period f o r

two hours a t 5OO0C.

Tes t (2) and, for a longer duration. Therefore, it can be concluded that p r i o r

removal of unincorporated phosphoric acid f rom the membrane by soaking i n

water is not at all deleterious t o fuel cell performance.

applies to membrane behavior during fuel cell operation as well.

Therefore , it was of interest to establish whether o r not this

Tes t (5) was performed on the membrane

The performance of this t e s t i s comparable to that of

Undoubtedly, this

Tes ts ( 9 ) , ( l o ) , (11) and (12) were performed with

platinum black being impregnated into both outer one-third l aye r s of the

membrane in the following manner .

membrane mater ia l (10, 20 , 30 or 4070 platinum by weight, the remainder

being C200B mater ia l ) is placed in a pressing die , followed by a layer of the

C200B membrane mater ia l and a second layer of the catalyst-bearing mater ia l .

The top punch i s then inser ted and the assembly (two-inch diameter) is p re s sed

at 15 tons total load.

re f rac tory plates and s intered in a i r for two hours at 500OC. After cooling to

room tempera ture , the composite membrane-catalyst wafer was impregnated

with 8570 phosphoric acid, oven dr ied at 12OoC and finally s intered at 5OO0C

f o r two hours.

photograph depicting the three l aye r s , given originally in Reference ( l ) , i s

shown again i n F igure 1.

A weighed amount of platinum-bearing

After pressing, the composites a r e placed on f la t , smooth

The phosphoric acid treatment was repeated twice. A

Tes t (9) i s actually a continuation of T e s t ( 2 ) , Table I

of Reference (2) . Although Tes t (9) containing the leas t amount of platinum,

was the most durable, its performance never reached the operational levels

of the o ther tes t s .

performance level as that of Test (21, without platinum impregnated in the

outer one-third l a y e r s ,

na ted into the membrane does offer advantages at higher tempera tures .

The t e s t s with more platinum were about the same in

However, i t will be shown below that platinum impreg-

SM-4622 1 -Q3 5

I I I I I I I I I I I I I I I ! I I

. 015

.015 (Approx. )

.015

Center Section of No. 194-003 Membrane Mat e ri a1

LSurface Sections of C200B Membrane Mater ia l -Plat inum Catalyst Mixture

F igu re 1. Fue l Cell Membrane - Catalyst Composite

I SM-46221 -Q3 6

I , I I I I I I I I I I I I I I I I I

It was noted a t this point that the fuel ce l l performance

level tended to remain essentially constant with increasing concentration of

platinum past 2070 in the outer one-third layers of the membrane.

prompted an effort with a membrane in which 2070 platinum was impregnated

in both outer one-tenth layers by the processing procedures descr ibed in

Reference (2) .

nonimpregnated C200B mater ia l constituted 80% of the total membrane. The

resul ts of the evaluation of this membrane a r e given in Tes t (13).

seen that there has been a significant enhancement in performance through this

type of membrane-catalyst formulation procedure.

the active a r e a for e lectro-catalysis is a t the sur face of the membrane only.

Any fur ther penetration of the membrane by the catalyst does not provide ad-

ditional s i tes for the appropriate catalytic reaction.

of e lectr ical shor t circuit ing is diminished by keeping the catalyst mater ia l as

c lose to the surface of the membrane as possible.

This

Therefore , the middle layer of the membrane consisting of

It can be

It may b e reasoned that

In addition, the possibility

Tes t (17), ( l 9 ) , (22) and (23) had been performed with

2070 platinum black in the outer one-third l aye r s of the membrane over the

tempera ture range of 93OC to 148OC. It appears that the performance remains

essentially constant over the temperature range of 65 to 12OoC, but appears to

diminish past 12OoC.

fuel ce l l operation a t temperatures in the range of 90° to 100°C when the non-

impregnated C200B membrane was used (Tes t No. 18). Apparently, the

impregnated platinum exerts a stabilizing influence on fuel ce l l behavior

above 65OC.

In this regard , it was not possible to obtain sustained

Tes t (21) performed with a 1070 platinum impregnated

membrane a t 100°C, does not reach the performance level of that of Tes ts

( 19) and (23) containing 2070 platinum-impregnated membranes and evaluated

a t comparable tempera tures . A similar correlat ion exists a t 65Oc. Of

fur ther significance, it is to be noted that the performance of the 1070 platinum

impregnated membrane a t 65Oc (Tes t 9) is essentially equal to that of the

s a m e sys t em a t 100°C (Tes t 21).

Tes t (20) was performed with 207’0 palladium black

impregnated in both outer one-third layers of the membrane. This sys tem

SM-46221-Q3 I 7

I, performed a s well as the corresponding all-platinum composite i n T e s t s (19) and (20) at 100°C fo r about 50 hours. Test (20) had been terminated because of

sharply diminishing performance a f te r 7 6 hours. It was observed upon opening

the t e s t cell that electrode pores were clogged with c lus t e r s of palladium black

powder. Evidently, significant amounts of catalyst had become separated f r o m

the membrane s t ructure .

platinum, it i s possible that approximately that much less palladium would be

required f o r equivalent effectiveness.

g ati on

I I I Since the density of palladium i s one-half that of

This ma t t e r is under cur ren t investi-

Tes t (15) was performed in connection with the

p r og ram to p r e pa r e integrated el e c t rode - cat a1 y s t - m emb ran e c omp o s it e s . The 0.1% palladium had been incorporated into the outer l aye r a f te r impreg-

nation of the membrane with platinum in 2070 concentration, followed by the

press ing and sintering procedure described above.

in Tes t (15) was not par t icular ly outstanding, probably because of the non-

porosity of the outer palladium layer , i t does demonstrate that it should be

possible to prepare integrated electrode-catalyst-membrane systems by this

technique. Such integrated assemblies have been prepared , wherein the

electrode component has been rendered porous by i ts being p res sed through

a s i lk sc reen as it is deposited on the membrane. They a r e to be evaluated

in the fuel cell in the nea r future,,

Although the performance ~

I I I

The various correlat ions of fuel cel l performance with

membrane thickness, concentration of impregnated catalyst and operation

tempera ture , a r e depicted in summarizing tables (Tables 11 - VI1 inclusive).

In these tab les , the fuel cell resistances as calculated f r o m polarization data

obtained at the indicated t ime interval of fuel cel l operation, a r e used fo r

cor re la t ive purposes in the following manner.

I I I I I I

Table I1 shows that f o r the nonimpregnated C2OOB

membrane , the res i s tance is unaffected by membrane thickness up to 0.75 mm.

However, beyond that point, resistance inc reases slightly with increasing

thickness.

Table 111 demonstrates the effect of platinum concen-

t ra t ion in the outer one-third l aye r s of the platinum-impregnated C200B

SM- 462 2 1 - Q3 8


increasing

r epo rt p e r

0 membranes on fuel cell res is tance at 65 C.

tion in the two outer one-third l aye r s , there is no fur ther reduction in fuel

cell res is tance.

Beyond 2070 platinum concentra-

Table I V shows the effect of 10% platinum with that of

2070 platinum in the outer one-third l aye r s of the platinum-impregnated m e m -

brane at 100°C.

than does 10% platinurn, a s had been noted at 65OC.

It is evident that 20% platinum affords a lower resis tance

Table V shows the effect of increasing tempera ture on

fuel cel l res is tance for a 2070 platinum-impregnated membrane ,

change in fuel cel l res is tance over the tempera ture range of 65

slight i nc rease occurs over the temperature range of 100°C to 125OC which

becomes m o r e significant as the temperature increases to 148 C.

T h e r e i s no

- 100°C. A 0

0

Table VI shows that palladium impregnated into the

C200B membrane is as effective at a s imilar concentration of platinum at

10oOc.

Table VI1 shows that impregnation of the C200B mem-

brane with platinum to the extent of 2070 i n the outer one-third l aye r compared

with the nonimpregnated C200B membrane does not lower membrane resis tance

a t 65OC; however, considerable improvement does occur at 82 C. 0

In connection with performance remaining essentially

constant over the tempera ture region of 65OC to 120 C , the following expla-

nation i s offered, Figure 2 (given previously in Reference 1) shows plots of

log resis t ivi ty ve r sus percent relative humidity determined f rom independent

experiments with the C200B membrane at 7OoC, 9OoC and 105OC.

fuel ce l l operating temperature the membrane dehydrates slightly causing its

resis t ivi ty to remain essentially at the same level as a t the lower tempera ture

(70 C). This condition exis ts because resis t ivi ty changes l i t t le with variation

i n re la t ive humidity at 70 C whereas , resist ivity dec reases significantly with

0

At higher

0

0

relative humidity at higher tempera tures ( 105°C).

3, 1. 2 ComDact Fuel Cell Life Tes t s

SM- 4622 1-Q3 9


3 10 -

2 10 -

19 - 20 30 40 50 60 7 0 8 0 90 100

70 Rela t ive Humid i ty COll.5

F i g u r e 2 . Log R e s i s t i v i t y V e r s u s P e r c e n t Re la t ive Humid i ty for the C200B M e m b r a n e a t 7OoC, 9OoC, a n d 105OC

10 SM-46221-Q3

I, I I I I I I I I I I I I I I I I I I

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U

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[U

0

l-4 d a, u d

k

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4

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Figure 4. Compact Fuel Cell in an Oven During Operation

I, *

I I I I I I I I I I roc77

a. 20 Mesh Stainless Steel Screen b. 'Forty-four Holes, 1 / 8 inch in Diameter, in Stainless Steel Back-up Pla te c . Ninety-six Holes, 1 / 8 inch in Diameter, in Stainless Steel Back-up Pla te

I I I I I I I I

Figure 5. F r o m Left to Right, 3 Types of Back-up Pla tes Used in Tes ts 6, 7 and 8 Respectively

SM-4622 1-Q3 13

I I I I I I I I I I I I

0 0 0 0 0 6, a d+

0 0 N

a,

rd U

4

a a 7 I

5 a

rd

w 0 a, a b b

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rd U

a" a 3 I

a w 0 v1 a, a b b

9

a, k

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the compact fuel cell unit as assembled in an oven i s shown in Figure 4.

resul ts obtained f o r tes t s depicting the most significant resu l t s are repeated

in Table VIII (initially l is ted in Table I).

using m a s s and heat t r ans fe r analysis and engineering experience.

description of the mathematical analysis is given in Section 3. 2. 3 below.

The

This fuel cell was optimally designed

A short

Fuel cel l operating res i s tances a r e cor re la ted in

Table IX fo r Tes t (6), (7) and (8) at 65OC in which a 20 m e s h sc reen as a

backup plate, a 44 hole backup plate and a 96 hole backup plate were used.

F igure 5 shows the three types of backup plates used and Figure 6 re la tes the

gas exposed a r e a as a fraction of the total cross-sect ioned a r e a f o r each back-

up plate.

as the gas exposed a r e a was increased the fuel cell performance a l so increased.

This phenomena will occur until contact area becomes c r i t i ca l and the overall . ce l l res is tance will rise again.

F r o m the resul ts of Table IX and Figure 6 , it can be concluded that

T e s t (14) has 2070 platinum black impregnated in both

outer one-tenth l aye r s .

the incorporation of platinum black in a thin l a y e r has no significant beneficial

effect on performance

It i s demonstrated now that in the 60° - 7OoC range,

Tes t s (17) and (22) were run in o rde r t o show how the

2070 platinum black membrane in the outer one-third l aye r s performed at the t o elevated tempera tures of 93 - 2 C and 128 2 l0C respectively. Charac te r i s -

t ically, the resis tance inc reases relativeiy l i t t le with increasing tempera ture

( f rom 0.43 ohms at 93 t o 2OC to 0.48 ohms at 128 - 1 C. )

T e s t (14) involving the s a m e 2070 platinum-impregnated

membrane affording optimum performance in the s tandard fuel cell (Test (1 3),

Table I) manifests a somewhat lower performance i n the compact fuel cell.

The re is a good chance that performance super ior t o that in Tes t (8) can be

achieved i f the 96 hole backup were used with this membrane. This ma t t e r

will be explored fur ther i n the nea r future. Efforts relating to the extent of

gas exposed a r e a of the backup plate to the compact fuel cell performance will

be continued as well.

proofing , membrane - catalyst and membrane - catalyst - electrode c onfi gurati ons , should lead to enhancement i n fuel cell performance to the 0.70 volt level at

2 m a / c m e

This , together with continued improvements in water

SM-4622 1 -Q3 15

I . I

I I I I I I I I I I I I I I I I

I 800

600

h

2

:

Y

Q) 400 M cd c, d

2oc

0

0 100 200

Time (Hrs )

0 Figure 'I. Synopsis of Fuel Cell Life Tes t a t 6521 C , Astropower

Zirconium Phosphate- Zeolon-H Membrane Voltage vs Time at Current Density of 30 ma /c rn2

SM- 4622 1 - Q 3

300

e06 76

16

I

600

400

200

000

0 I

100 200

T i m e (Ers)

3

F i g u r e 8 . Synopsis of Li fe Tests a t 66*2OC, Tes t 13 , Table I Vo l t age v s T i m e a t C u r r e n t Density of 30 m a / c m 2

17

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SM-4622 1 4 3

rn

L? r- 9

--N -

0 0 m

0 0 v

0 0 rn

0 -0

4

h

c\1

0 - 9

- 0 v

0 - N

- 0

E

E

0

rd \

Y

r

c

c, .r(

rn

a" c, c a, k k I u

20

I+ 4 9 u 4 9

P) c rd k P E 2 0

c fd M k 0 c

.e4

H

k 0 w

0 0 0 d

1'1 e,

w

2 v)

2 rr) N 4

0 0 0 0 r- a

I i a, w 2 2 v)

N 9 N

0 0 0 0 m -+

4 A a, W a, 3

Gc

A

0 -9

h

N

E u \

;

a"

Y

$. U .rl

v) c

U c e, k k 3

-0 u rr)

P E a,

Id M k 0 r: H

Id N d ;

-0

SM-4622 1 -Q3 21

I , I I I I I I I I I I I I I I I I I I

t

C C C

C C

f al 2 4

o\ C 4

S M- 462 2 1 - Q 3

f I-r 0

I

4 - 4 c

C -r

N

f U

Y

>. - = .%

v) rc

c v a I.r c j,

- 0 N

22

I

I I I I I I I I I I I I

The synopsis of voltage-time data f o r T e s t s (8) and (13)

Polarization curves fo r T e s t s (5), a r e given in Figures 7 and 8 respectively.

(8), (13), (14) and (19) a r e given in Figures 9-13,respectively.

3 ., 2 C at al y s t - Membrane and Elect rode - C at a1 y s t - Mem b ran e

Prepara t ions by P r e s sing and Sintering Techniques

Work has continued during this report per iod devoted t o the

development of composite fuel cel l membrane-catalyst fo r components.

a r e prepared by pressing together three l aye r s of ma te r i a l , the two outer

l aye r s being composed of mixtures of C200B membrane ma te r i a l and catalyst

and the center section being G200B mater ia l without the catalyst addition.

Each section has been approximately 0.38 mm thick result ing in a p res sed

composite about 1. 2 mm thick,

and diff u si on bonded

These

After press ing , the composites a r e s intered

As descr ibed above in Section 3, 1 .1 , t he re appears to be

advantages in employing thinner outer catalyst l ayers .

investigation.

This i s under cur ren t

Catalyst- Membrane Composites

The following membrane- c atalyst composites have been prepared

o r a r e i n preparat ion f o r fuel cell evaluation.

Same Catalyst Layer on Both Sides of Membrane

10& Pt - 90% C200B

207’0 Pt - 807’0 C200B

3070 Pt - 7070 C200B

40% Pt - 6070 C200B

10% P d - 9070 CZOOB

207’0 P d - 8070 C200B

30% P d - 7070 CZOOB

4070 P d - 607’0 C200B

1070 (50% Pt - 5070 Pd) - 9070 C2OOB

23

I . I c I

Different Catalyst Layer on Each Side of Membrane

10% (50% Pt - 50% l r ) - 90% C200B @I2 Side]

10% Pt - 90% C200B (02 Side)

10% (50 Ag - 5070 Pd) - 90% C200B (02 Side)

1070 Pt - 90% C200B (H2 Side’)

As the maximum concentration and type of catalyst producing

the best fuel cel l operation i s determined, the thickness of the outer catalyst

bearing l aye r s will be reduced to the minimum consistent with optimum fuel

cell operation.

thickness as well.

l aye r s containing at leas t 207’0 Pt, can be reduced by at leas t three-fold.

This will resu l t s in reducing both catalyst cost and membrane

It appears , fo r example, that the thickness of the catalyst

Electrode - Catalyst - Membrane C omposit e s

Work is a l so being performed on the incorporation of e lectrodes

These samples a r e prepared by the into the catalyst-membrane composites.

following two different technique s :

Screen Electrodes

Screen electrodes a r e p r e s s e d into the catalyst-membrane

composite and sintered as descr ibed above,

Silk Screen Electrodes

Electrode mater ia l s such as platinum, palladium, i r idium

and other materials are silk screened on the sur faces of the

p re s sed catalyst-membrane composite as descr ibed above

ei ther before or after sintering, If applied a f te r sintering

the assembly i s then re f i red to bond the electrode l aye r s to

the catalyst-membrane composite.

A. Screen Electrodes

1. Silver ~71 2. Tantaium Mesh I 1 PLATINIZED 3. Nickel Mesh 4, Stainless Steel Mesh

SM- 4622 1-Q3

5. Gold Mesh 6, Platinum

24

B. Silk Screen Electrodes

1. Platinum 2. Palladium 3. Tantalum 4. Iridium

The evaluations f o r these ma te r i a l s a r e i n p rogres s at the

present t ime

3 . 3 Mass and Heat Transfer Analysis of Optimum Fuel Cell Design

P a r a m e t e r s

The operation of a hydrogen-oxygen fuel cell i s par t icular ly

sensit ive to the proper water balance existing between the ra tes of water vapor

removal f r o m the electrode surface,,

balance about the electrodes would result in e i ther a drowning o r dehydration

of the membrane-electrode composite. Consequently, a mathematical analysis

was conducted to determine the optimum engineering design pa rame te r s f o r a

flow-type fuel cell.

l e s s pa rame te r s ; namely, the relative gas velocity (+ b/D ), relative mean

discharge humidity (R/H ) and the relative width of gas passage (-1.

Fa i lu re to maintain the optimum water

The design will be formulated in t e r m s of th ree dimension-

V b

S a

3 . 3 . 1 Mass Transfer Analysis

In principle, water is generated at the catalyst interface

which sweats through the electrode surface. Simultaneously, the vaporization

of water vapor into the gas passage serves to remove the heat generated in the

electrolyte-bearing membrane , the p r imary mode of heat removal,

The water remval process i s formulated quantitatively

by writ ing the differential equation about a differential element of gas in the

flow stream. It is given by Equation (1) below.

Equation (1) descr ibes the equality between the convection of water vapor =Innu the m a c passage a.nd the diffusion of water vapor a c r o s s the flowing ----- a--

stream. The boundary conditions, given below, to this m a s s t r ans fe r

problem depict the sur face conditions of the electrode.

S M- 4 62 2 1 - Q 3 25

H = H o at x = o a n d z = o (2)

H = H s at x = o a n d z = a (3)

The solution to this sys tem of equations f o r the gas humidity prof i le in the

plane o r the discharge por t i s given below,

(H - Hs) / (Ho - Hs) = er f (3b2 /4aDv) 1 / 2

By integrating Equation (4) a c r o s s the width of the gas passage, the average

discharge humidity fi of the gas leaving the fuel cell is given as follows:

Equation (5) is presented graphically in Figure 14,

The optimum engineering design pa rame te r s a r e obtained

graphically by plotting the relative gas velocity (v b/D 1 ver sus the relative

width of the gas passage (b /a ) at constant values of the relative mean discharge

humidity @/H ).

humidity, the optimum design parameter (b /a ) is 0. 208.

the prevailing cell geometry fo r the Astropower compact fuel cell , descr ibed

in Section 3 , l e 2, Exceedingly lower values would resul t at increased satura-

tion of flowing gas,

V

Figure 15 is based upon (H/Hs) = 0.95. F o r this discharge S

This i s essentially

In conclusion, the mathematical analysis resulted in

the determination of the engineering design pa rame te r s pertinent t o the

optimum operation of a hydrogen-oxygen fuel cell.

similar to those of Figure 14 can be used to evaluate the discharge gas

humidity, R a s a function of the g a s velocity, and the width of the gas

passage bo

(v b/Dv) and (b /a ) evaluated in this analysis can be determined f r o m curves

similar to those of F igure 15.

In general , design curves

The optimum dimensionless design pa rame te r s (R/H S

3, 3 , 2 Heat Transfer Analysis

A r;lathemzaticil a r d y s f s wa s conducted t o determine

the heat rejected f rom the electrodes of a fuel cell.

the sur face of the electrodes due to the electrochemical reactions and 1 R

The heat generated over 2

26

I I I I I I I I I I I I I I I e I I I

1 . 0

0.1

0 . 0 1

1 . 0 D

F igure

SM-4622 1-Q3

/

/ Ratio b / a = '1

b I

Douglas IEX Membrane

0.9 0. 8 0 . 7 0 . 6 0. 5 0.4 mensionless Average Discharge Humidity, H/H

S

14. Discharge Gas Humidity vs Fuel Cell Geometry

C064S

27

I .

I 0.4 -

0.3 -

tz

0 . 2 -

0 .1

0

0

D i s c h a r g e Humidi ty of S ing le C e l l R=O. 95 Hs M e m b r a n e T e m p e r a t u r e = 1 OO°C

0 . 1 0 . 2 0 . 3 0 . 4

Width of G a s P a s s a g e , b / a

F i g u r e 1 5 . Op t imized F u e l C e l l Des ign

0 . 5 0 . 6

r0rr.f

SM- 4622 1 -Q3 28


l o s ses i s assumed to be uniform over the ent i re a rea . It i s dissipated by the

process of water vaporization to the flowing gas s t r e a m , thereby, increasing

the discharge gas tempera ture f o r a specific gas velocity.

To descr ibe this thermal behavior of the flow type fuel

cel l , an energy balance was writ ten across a differential volume of flowing

gas. Under steady flow conditions, the resultant heat t ranspor t equation is

given below,

Equation (6) represents the balance between the convective t ranspor t of energy

along the flow path and the the rma l t ransport of energy a c r o s s the flowing gas

stream by conduction.

The boundary conditions , being of the homogeneous type,

a r e formulated on the basis that the heats of electroehemical reaction are

generated at a constant ra te , q over the ent i re electrode surface. The

equivalent expressions a r e given below. 1

T = T 0 at z Z= 0 between (o < x e b] (7)

(a T a Z I ~ = ~ = qo/k at x = 0 between Q o < z < a ) 48)

The analytical solution t o Equations (61, (7) and ( 8 ) in

t e r m s of dimensionless pa rame te r s i s given below.

Equation (9) represents the temperature profile a c r o s s the flowing gas s t r e a m

in the plane of the discharge port. Although the minimum thermal variation

will occur at gas ra tes in excess of the stoichiometric l imi t s , the maximum

inc rease in the gas temperature a t the electrode surface i s attained at high

cel l efficiencies for a fuel cell operating under adiabatic conditions a t the

stoichiometric ratio of the reactants. Under these conditions, the thermal

ra t io (T / t ) at the electrode surface could exceed the bulk gas s t r eam value

uy 1L.V pelLeLlt. s o

1. i ? n

SM-46221 -Q3 29


NOMENCLATURE

P

C P -

V

T

z

k

X

b

a

90

*O

H

D V

Fi

HS

HO

e rf

e r fc

3 .4

3 = gas density, lb mass / f t

=

= gas velocity, f t / s e c

= Tempera ture , R

= Position along gas flow, f t

=

=

=

=

= Heat f l u x at electrode surface, Btu/(ft ) (sec)

= Inlet gas tempera ture , R

=

=

=

=

=

=

= Complement of probability integral

Additional Studies - New Catalyst and Water-Proofing Studies

Several pa i r s of electrodes were fabricated using tantalum sc reen

heat capacity, Btu/ (lb m a s s ) (OR)

0

Thermal conductivity, (Btu) f t / ( s q f t ) ( sec) (OR)

Position a c r o s s gas flow, f t

Width of gas passage , f t

Length of gas passage, f t

2

0

Humidity of gas s t ream, l b mass wa te r / lb m a s s gas

Molecular diffusivity, sq f t / s ec

Average gas humidity, lb mass wa te r / lb mass gas

Saturated gas humidity at electrode, l b mass w a t e r / l b mass gas

Inlet gas humidity, lb mass wa te r / lb mass gas

P r o ba bilit y int e gra l

and a var ie ty of catalysts and water-proofing agents.

the catalyst .

methods: electrodeposition o r application of a "paste" o r s lur ry . Electro-

deposition was c a r r i e d out in 370 H2PtC16(aq).

eight nf s c r e e n ) of p l ~ t i ~ 1 - 1 ~ X , X J ~ ~ depnsfted. in this fashion,

pas tes consisted of platinum black suspended in a toluene solution of silicone

Platinum was used a s

It was applied to the two-inch diameter s c reens by ei ther of two

Up to 4070 by weight (total

The platinum

30

I . I I I I I I I I I I I I I I I I I

res in (G.E. SR-224). After application of the paste , the toluene was evaporated

and the res in cured at 9OoC.

Other catalysts were a l s o applied to tantalum s c r e e n s by the

"pasting" technique.

binder. The catalysts employed were palladium, nickel boride, and cobalt

boride.

Silicone res in was invariably used as the water-proofing

The finished s c r e e n s contained f r o m 30% to 40% by weight catalyst .

Severa l of the successful e lectrode sc reens a r e being evaluated

in working fuel cel ls ,

evaluated.

A few of the above e lec t rodes a r e cur ren t ly being

SM-4622 1 -Q3 I 31

I I I I

I I I I I I I I I I I I I I

I

4.0 FUTURE WORK

( 1) Studies involving new catalyst -membrane composites and electrode-

catalyst -membrane composites as indicated herein will be continued.

(2) Studies with the compact fuel cel l will b e continued. A l a rge r ce l l

Tes t s will be constructed capable of handling a four-inch diameter mamebrane.

will b e per formed with this unit.

(3) Efforts will b e directed toward the water-proofing of electrodes.

I t is planned to attempt to improve fuel ce l l performance by providing the com-

pact unit with a wicking arrangement .

SM-46221 -Q3 32

5 . 0 REFERENCES

(1) "Inorganic Ion Exchange Membrane Fue l Ce l l t t NASA-Lewis Center Contract NAS 3-6000, Quarter ly P r o g r e s s Report

SM 46221-Q1, P e r i o d Ending 10 October 1964.

( 2 ) Ibid, Quarter ly P r o g r e s s Report SM 46221-Q2, Pe r iod End-

ing 10 January 1965.

( 3 ) Ibid, Monthly P r o g r e s s Report fo r Pe r iod Ending 10 F e b r u a r y 1965.

I (4) Ibid, Monthly P r o g r e s s Report f o r P e r i o d Ending 10 March 1965.

I I I I I

I

I

I

I

I 1 I SM 46221-Q3 3 3

I I I

I I I I I I I I I I I I I

i

I

6 . 0 PROJECT PERSONNEL

The following Astropower staff personnel were connected with the

p rogram during this reporting period:

Dr. C. Be rge r , Pr inc ipa l Investigator

Dr. M. P. St r ie r

Mr . F. C. Ar rance

Dr. L. 0. Rutz

Mr. G. Belfort

Mr. A. G. Rosa

Mr . R. Hubata

SM 46221-Q3 34

I. I I I I I I I I I I I I I I I' I I I SM- 46221 - Q 3

n d .?

m o o o o Q ) t - o m m m m m o m m o ' o ' l I . . . . . . 0 ~ 0 0 0 0

9 9 W N N N m m n * e * . I I d d d 0 0 0

O I - m N N + L n I n I n I n m N N ~ 0 0 99999999

00000000 . . . . . . . .

1

+I m 9

m m 0

J N O P -eo'- -

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D S P - 1 r l N N r * I

3 0 0 0 . . . .

n m N m n s r n m 0 9 9 9

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0 9 m m s n i g i

-. U

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c L:

E" d m b - - fd U al

ul

0

.d

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z

t-

~ O ~ I ~ O O N N > o o o o o m m , m o ' m m o ' m m > o o o o o o o . . . . . . . .

> o o o o o o o 1N""NN . . . . . . . ; o o o o o o o

- 0 - r - O F - 0 0 3 0 0 0 0 0 0 0 - t - I c r - P - t - P - F - ; d d o o o o o . . . . .

> o o o o o o o ;ddddddd o a m x m a o a o m

. H

3

c

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35

c .

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al c - c V

i

I I I I I I I I I I I I I I I ' I I I

N 9 IC1

. . . . . 00000

- + 0 c) P Q + I- J + I- e - 9 o \ -

- 4 - N

4 N N N Q l n - m m m m m m e . . . : d d d d o o o

~ t - N r - t - O N - ( ' m M Q 9 V l L C l c ) > 9 Q Q Q Q Q Q

> o o o o o o o . . . . . . . .

- t - o t - r - m - m

p m m m m m m b . . . . . . . . - * N V I V I O - Q

. H n

c) c) I- r- - m

0 0 0 0 0 0 0 0

N N N N N N m l n . . . . . . . .

e o o e e m m o ~ r - r - r - t - r - P - Q Q > O N N O O O ~ ~

; d d d o o o o o . . . . .

D 3

- al M nl a x Y C

4

d

C

u

36

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SM- 462 2 1 - Q 3

JN

b 0 J *

. .

7

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r n 3

ro r'x 7m

n

n n

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D 3 -

. . . . . . 3 0 0 0 0 0

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0) M d P

/ d C

c

c r c u

37

SM- 4 622 1 - Q 3 38

TABLE I1

COMPARISON O F RESISTANCE FOR STANDARD NON-IMPREGNATED MEMBRANE AT VARIOUS TEMPERATURES

Tempera ture OC Thickness mm

0 . 0 0 - 0.50

.O. 50 - 0 . 75

0 .75 - .l. 00

Resis tance - (Ohms) 25OC

Fue l Cell T e s t No.

0. 66 /1

0.74 '(4

'From Reference (2) - Fue l Cell Tes t No. 1

(b)From Reference (2) - F u e l Cell Tes t No. 5

a

SM-46221 -Q3

65OC Fue l Cell T e s t No.

0 . 29 '3

0 . 29 4b)

0 . 3 3 I2

39

1 .

TABLE 111

RESISTANCE COMPARISON AT 65* 2OC AND VARIOUS TIME INTERVALS FOR CONCENTRATIONS O F PLATINUM BLACK IMPREGNATED IN

THE OUTER ONE-THIRD LAYERS

Resis tance (OHMS) a t 65* 2OC

T i m e (Hours) 0 - 50 50 - 100 100 - 150 150 - 200 200 - 250 250 - 300 %-Pt Tes t No. -

10 9 0.62 0. 62 0.55 0. 5 1

20 10 0 .33

30 11 0. 36 0. 32

40 12 0.27 0 .27

0. 32 0.35

0. 36

0 .41

40


T A B L E IV

COMPARISON O F RESISTANCE AT 100% 2OC AND VARIOUS T I M E ' I N T E R V A L S FOR 10 AND 20 P E R C E N T P L A T I N U M B L A C K

' I M P R E G N A T E D IN T H E OUTER ONE-THIRD LAYERS

R e s i s t a n c e (OHMS) at 100% 2OC

Time ( H o u r s ) 0 - 50 50 - 100 100 - 150 150 - 200 200 - 250 250 - 300 % - P t T e s t No.

- - 10 21 0 .40 0. 56 0 . 5 0

20 l 9 , 2 3 0. 24 0. 36 0 .37 0 .35

SM-46221-Q3 41

TABLE V

COMPARISON O F RESISTANCE FOR 20 PERCENT PLATINUM BLACK MEITER ANE IMPREGNATED IN THE OUTER ONE-THIRD LAYERS

AT VARIOUS TEMPERATURES

Tempera tu re C 0

Resis tance - (OHMS)

65 f 2 85 f 2 100 f 2 125 f 3 148 f 2 2

(a) Res is tance (ohms) 0.33 0. 30 0.35 0 .45 0.72

Membrane Thickness 0.93 (mm) 1. 15 1.06 1.43 1 .43 1 .43

Fue l Cell T e s t Number

19 10 16 23 23 23

(a) After approximately 50 hours

SM-46221-Q3 42

TABLE VI

COMPARISON O F RESISTANCE AT 100 & 2OC AND VARIOUS TIME INTERVALS FOR 20 PERCENT PLATINUM AND PALLADIUM-BLACK

CATALYST IMPREGNATED IN THE OUTER ONE-THIRD LAYERS

Resis tance (OHMS) at 100 i 2OC

Time (Hours) Catalyst

70 Pt. T e s t No. zo 19 ,23

70 Pd. 7 20

0 - 30 30 - 4 0 40 - 50 50 - 60 60 - 70 70 - 80

0.34 0.37 0.40

0.41 0 .33 0.33 0.35

4 3

I, I I I I I I I I I I I I I

? 0

u -7

0

-H m Q

V F l m

a, d

c o b C O Q

0 0 . .

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SM-46221-Q3 45

, -

TABLE IX (a)

COMPARISON O F RESISTANCE FOR THE COMPACT F U E L C E L L DESIGN USING VARIOUS BACK-UP PLATE CONFIGURATIONS

Fue l Cell T empe r a t u r e Res is tanc e T e s t Numb e r Type of Back-up P l a t e C Ohms

0

8 20 gauge s ta in less steel s c reen 65 f 1 0.62

9 44-Hole s ta in less s tee l 1/8" 65 f 1 0.26 thick disc

10 92-Hole s ta in less s tee l 1 /8" 65 f 1 0.20 thick disc

(a) Noted a f t e r approximately 50 hours.

SM-46221 -Q3 46

DISTRIBUTION LIST FOR CONTRACT NAS 3-6000

National Aeronautics & Space Administration Code ATSS-10 Washington, D. C . 20546 Attention: Miss Millie Ruda (3)

National Aeronautics & Space Administration Scientific and Technical Information Faci l i ty P . O . Box 5700 Bethesda, Maryland 20546 ( 2 cys. & 1 r e p r o . )

National Aeronautics & Space Administration Code MAT Washington, D. C. 20546 Attention: George F. Esenwein

National Aeronautics & Space Administration Washington, D. C. 20546 Attention: W. C. Scott , Code RNW

E. M. Cohn, Code RNW J . L. Sloop, Code RC A. M. Greg Andrus, Code ST J . R. Miles , S r . , C o d e S L

National Aeronautics & Space Administration Goddard Space Flight Center Greenbelt , Maryland 20771 Attention: Tom Henigan

H. Carleton J . Shirfey

National Aeronautics & Space Administration Lewis Resea rch Center 21000 Brookpark Road Cleveland, Ohio 441 35 Attention: N. D. Sanders - MS 302-1

M. J . S a a r i - MS 500-202 R. L. Cummings - MS 500-201 B . Lubarsky - MS 500-201 H. J . Schwartz - MS 500-201 J . E . Dilley - MS 500-309 D. G . Soltis - MS 500-201 J . J . Weber - MS 3-16 W . J . Nagle - MS 500-201

National Aeronaut ics & Space Administration Marsha l l Space Flight Center Huntsville, Alabama 35 8 12 Attention: Phi l ip Youngblood

National Aeronautics & Space Administration Manned Space c raf t Center Houston, Texas 77001 Attention: E. J . Meeks

W i l l i a m Dus enbury

National Aeronautics & Space Administration J e t P r o pul s ion Lab0 r ato r y 4800 Oak Grove Drive Pasadena , California 91 103 Attention: Aiji Uchiyama

U . S . Army R&D Liaison Group (9851 DV) APO 757 New York, New York Attention: B. R. Stein

U. S. Army Resea rch Office Box CM, Duke Station Durham, North Carol ina Attention: Pau l G r e e r

D r . Sidney J . Magram Army Resea rch Office Office, Chief R&D Department of the A r m y 3D442, The Pentagon Washington 25 , D. C .

Commanding Officer U . S. Army Signal R&D Lab. F o r t Monmouth, New J e r s e y Attention: Power Sources Division

Commanding Officer Diamond Ordnance Fuze Labs. Washington 25 , D.C. Attention: Power Sources Branch

Direc tor U.S. Army Engineer R&D Lab. F o r t Belvoir , Virginia Attention: Power Sources Branch

Advanced Concepts Division Bureau of Ships (Code 350) Washington 25, D. C . Attention: B. Rosenbaum

Dr . Ralph Roberts Head, Power Branch Department of the Navy Office of Naval Resea rch Washington 25, D. C.

National Aeronautics & Space Administration Western Operations Office 150 Pic0 Boulevard Santa Monica, California 90406 Attention: P. Pomerantz

Department of the Navy Office of Naval Research Washington 25, D. C. Attention: Har ry Fox

Electrochemical Branch Naval Research Laboratory Washington 25, D.C. Attention: J . C. White

U . S . Naval Ordnance Laboratory Department of the Navy Corona, California Attention: W i l l i a m Spindle r

U . S o Naval Ordnance Laboratory White Oak -Silver Spring, Maryland Attention: Philip Cole

Commander A i r F o r c e Cambridge Research Labs. Attention: CRO L. G. Hanscom Field B edfo r d , Mas s achus e t t s

Captain W i l l i a m Hoover A i r F o r c e Ballist ic Missi le Division Attention: WDZYA -2 1, A i r Fo rce Unit Pos t Office Los Angeles 45, California

Wright A i r Development Division Wright-Patterson A i r F o r c e Base Dayton, Ohio Attention: WWRMFP-2

Commander Rome Air Development Center Griffiss A i r F o r c e Base , New York Attention: RAALD

Headquarters

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TJSAF (AFRDR-AS)

Office of Technical Services Department of Commerce Washington 25, D.C.

Advanced Research P ro jec t s Agency Washington 25, D . C. Attention: D r . John Huth

U . S. Atomic Energy Commission Division of Reactor Development Auxiliary Power Branch (SNAP) Washington 25, D. C. Attention: LCOL George H. Ogburn, J r .

I

I

Power Information Center University of Pennsylvania Moore School Building 200 South 33rd S t r ee t Philadelphia, Pennsylvania 191 04

Armed Serv ices Technical Information Agency Arlington Hall Station Arlington, Virginia 22212 Attention: TISIA

Office, DDR&E: USW & BSS The Pentagon Washington 25, D. C. Attention: Mr . G. B . Wareham

Institute of Defense Analysis 1825 Connecticut Avenue, N. W. Suite 100 Washington 9, D.C.

P r o f e s s o r John O'M Bockr is E l e c t r o c hemi s t r y Lab o rat0 r y University of Pennsylvania Philadelphia, Pennsylvania 191 04

United A ir c raft C o r po rat ion P r a t t & Whitney Ai rc ra f t Division East Hartford, Connecticut 06108 Attention: Lib rar ian

Bel l Telephone Labora tor ies , Incorporated Mur ray Hill, New J e r s e y Attention: D r . U . B . Thomas

Johns Hopkins Universi ty Applied Phys ic s Laboratory 8612 G e n r g i a Avenue Si lver Spring, Maryland Attention: W . A. Tynan

Hoffman Elec t ronics Company Re s e a r c h Labora tory Santa B a r b a r a , California Attention: Dr . Joseph Smatko

I . Yardney Elec t r ic Corporation New York, New York Attention: D r . Paul Howard

Radio Corporation of America As t ro Division Heightstown, New J e r s e y Attention: D r . Seymour Winkler

Radio Corporation of America Somerville, New J e r s e y Attention: D r . G. Lozier

Elec t ro -Optical Systems, Incorporated 170 North Daisy Avenue Pasadena, California Attention: E. Find1

ESSO Research and Engineering Company Products Research Division P . O . Box 215 Linden, New J e r s e y Attention: Dr . C a r l Heath

General Elec t r ic Company Direct Energy Conversion Operations Lynn, Massachuset ts Attention: D r . E . Os te r

General Elec t r ic Company Resea rch Laboratory Schenectady, New York Attention: D r . H. Liebhafsky

Genera l Elec t r ic Company Missi le and Space Vehicle Department P . O . Box 8555 Philadelphia, Pennsylvania 191 0 1 Attention: M r . A. D. Taylor

S&ID Division North American Aviation, Incorporated Downey, California Attention: D r . J a m e s Nash

McDonnell Ai rcraf t Corporation P . O . Box 516 St. Lcu is , Missouri 631 66 Attention: Pro jec t Gemini Office

General Motors Corporation Allison Division Indianapolis , Indiana 46206 Attention: D r . Robert E. Henderson

Allis -Chalmer s Manufacturing Company 1100 S. 70th S t ree t Milwaukee, Wisconsin 5 320 1 Attention: D r . T . G. Kirkland

Space Science Laboratory University of California Berkeley, California 94704 Attention: Charles W . Tobias

Western Reserve University Cleveland, Ohio 44106 Attention: D r . E rnes t Yeager

General Motors Corporation Box T Santa Barba ra , California Attention: D r . C. R. Russell

Dr . A . Fle ischer 466 South Center Street Orange, New J e r s e y

D r . J . G. Cohn Englehard Industries 497 Pelancy St ree t Newark, New J e r s e y

Battelle Memorial Institute 505,.King Avenue Columbus, Ohio 43201 Attention: Dr . C. L. Faus t

V . P. Engineering Globe Union, Incorporated Milwaukee, Wisconsin 5 320 1 Attention: Dr . C. K . Morehouse

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