Feb. 13, 1968
M. s. TOY
3,368,926
LOW TEMPERATURE ELECTROCHEMICAL CELLS AND BATTERIES
Filed April l5, 1966
2 Sheets-¿Sheet 1
4.5
4.7
4.9
Feb. 13, 1968 ,
M. s. ATOY
3,368,925
LOW TEMPERATURE ELECTROCHEMICAL CELLS AND BATTERIES
Filed April l5, 1966
2 Sheets-Sheet 2
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3,368,926
United States Patent Oiiiice
Patented Feb. 13, 1968
2
SPECIFIC CONDUCTIVITIES OF SOME NITROSYL AND
NI’I‘RYL SALTS IN LIQUID NITROSYL FLUORIDE
3,368,926
LOW TEMPERATURE ELECTROCHEMICAL
Solute
CELLS AND BATTERIES
Concentration
(mole/líter)
Temperature
(° C.
Specific Con
ductivlty (ohm-l
cmrl)
Madeline S. Toy, Fountain Valley, Calif., assigner, by
mesne assignments, to the United States of America as
0.403
0. 379
0. 446
1.0
1, 0
Pure
Pure
represented by the Secretary of the Army
Filed Apr. 15, 1966, Ser. No. 543,773
7 Claims. (Cl. 136-155)
_90
-90
-90
_80
-80
-80
_90
4. 42 ><10-a
1. 33><10-2
5. 41 X10-3
1.15)(10-2
1.(ì3><10-2
6. 24)(10-5
3. 95><10-5
This invention relates to a new and improved type of
electrolytic cell and has particular relation to an electro
The effect of the addition of the nonpolar Lewis acids
lyte solution for use therein.
to nitrosyl fluoride can more easily be seen by reference
In electrolytic cells or batteries intended for extreme 15 to FIGURE 1 which depicts specific conductivities as a
low-temperature service, the electrolyte employed must
function of concentrations of BF3, PF5, and ASF;J in NOF
have a eutectic point at a temperature below that antic
ipated in the intended service. In the relatively new field
solutions at _60° C. At that temperature the specific
conductivity increases proportionately with the addition
of cryogenics, experimentation concerns itself with tem
of the acid, reaching maximum conductivity at a con
peratures of _60° C. and below. There are times during 20 centration of approximately 0.286 mole per 1000 grams
such experimentation when an internal power source is
of NOF for PF5, 0.336 mole per 1000 grams of NOF for
desirable. The ordinary dry cell becomes inoperative at
AsF5, and 0.304 mole per 1000 grams of NOF for BF`3.
about _20° C. and even recent improvements lower its
As can be further derived from FIGURE 1, at the stated
operability to only _50° C. At these lower limits of
maximum effective concentrations the approximate speci
temperature the electrolyte solution freezes and the inter 25 fic conductivities are 9.0><10'-1 ohm*1 cm?1 for PF5,
nal resistance of the cell 'becomes very high.
1.9><10-2 ohm-1 cm.-l for AsF5, and 3.8><10-2 ohm*1
An object of the present invention is to provide an
cm.-1 for BF3.
electrolyte solution for a low-temperature electrolytic
FIGURE 2 illustrates the specific conductivity as a
cell which will permit efficient operation from _60° C.
t0 _132° C.
30 function of temperature of varying concentrations of
BF3 in NOF. At a concentration of 0.304 mole BFS per
Another object of the invention is to provide an electro
1000 grams of NOF, the specific conductivity decreases
lyte solution which will have desirable dry cell character
as the temperature decreases, from a high of 3.5X10-2
istics, including solubility of the salts contained therein,
ohm-1 cm.“1 at _60° C. It can be seen that the BF3
freezing temperature, viscosity, resistivity, temperature
coeñicient, acidity and satisfactory chemical reactions
35
with other constituents of the cell at low temperatures.
These and other objects of the invention will be better
understood by reference to the accompanying description
and by the curves shown in FIGURES 1 to 4 of the
drawings.
ship between temperature and the specific conductivity
40 of various concentrations of phosphorus pentafluoride in
nitrosyl ñuoride. The most suitable concentration is 0.286
mole of PF5 per 1000 grams of NOF which, for example,
has a specíñc conductivity of 9.3><10“1 ohm"1 crn?1 at
I have discovered that liquid nitrosyl liuoride is an
excellent ionizing solvent. It has a relatively high degree
of self-ionization which probably occurs in the following
manner:
solution exhibits considerably greater specific conductivity
than pure NOF which has a specific conductivity of
9.5 X 10-3 ohm-1 cm.-1 at _60° C.
In the same manner, FIGURE 3 describes the relation
_80° C.
45
-
Similarly, FIGURE 4 shows AsF5 in the context of
concentration, temperature and speciñc conductivity. The
suggested concentration of arsenic pentañuoride is 0.336
mole per 1000 grams of NOF. That solution has a specific
The advantages of nitrosyl fluoride as a solvent for
conductivity of 4.0><10-2 ohm-1 crn.-1 at _90° C.
electrochemical cells and batteries are: (l) its low tem 50
While only preferred forms of the invention are shown
perature liquid range (M.P. _132° C. and B.P. _60°
and described, other forms thereof are contemplated and
C.), (2) its solvation characteristics enabling it to form
numerous changes and modifications may be made therein
highly conductive electrolytic solutions (10`2 ohm-1
without departing from the spirit of the invention as set
cm.-l) at temperatures below _60° C., and (3) its high
forth in the appended claims.
eiectrochemical energy potential due to higher free energy 55
What is claimed is:
change of fluorination reactions as compared to oxidation
1. A low-temperature battery having an electrolyte
reactions.
therein, said electrolyte comprising liquid nitrosyl fluoride.
Further, experimentation indicated that liquid nitrosyl
2. The electrolyte set forth in- claim 1, including at
fluoride is a good ionizing solvent for nonpolar Lewis
least one nonpolar Lewis acid from the group of acids
acids such as boron trifluoride, phosphorus pentañuoride 60 consisting of phosphorus pentañuoride, arsenic pentaliuo
and arsenic pentafluoride and the nitrosyl (e.g. NOBF4,
ride and boron triñuoride.
NOPFG, NOAsFS) and nitryl (eg. NOzAsFß, NO2SbF6)
3. The electrolyte set forth in claim 2, wherein phos
salts of such a-cids. These mixtures form highly conduc
phorus pentafluoride comprises up to 0.286 mole per one
tive electrolytic solutions at temperatures below _60° C.
thousand grams of nitrosyl ñuoride, arsenic pentañuoride
- 3,368,926
3
comprises up to 0.336 mole per- one-thousand grams of
nitrosyl iiuoride, and boron triñuoride comprises up to
0.304 mole per one-thousand grams of nitrosyl fluoride.
4. The electrolyte set forth in claim 1, including at
least one nitrosyl salt from the .group consisting of
4
7. The electrolyte set forth in claim 6, wherein the
concentration of NOZASFG is 1.0 mole per liter of NOF
and of NO2SbF6 is 1.0 mole per liter of NOF.
References Cited
UNITED STATES PATENTS
NOBF4, NOPF6, and NOASFS.
5. The electrolyte set forth in claim 4, wherein the
concentration of said NOBF4 is 0.403 mole per liter of
NOF, of NOPFG is 0.379 mole per liter of NOF, and 0f
NOAsFß is 0.446 mole per liter of NOF.
6. The electrolyte set forth in claim 1, including at
least one nitryl salt from the group consisting of
NOzAsFß and NO2SbF6.
2,773,786
12/1956
2,950,999
8/1960
Jobe ____________ __
Craig et al ________ __ 136--155
3,320,140
5/1967
Yodis _____________ _- 204-59
ALLEN B. CURTIS, Primary Examiner.
D. L. WALTON, Assistant Examiner.
136-155