Improvements in an Electrolyte and Depolarizing Solution for Voltaic Batteries.
Year: 1887

page_text: COMPLETE SPECIFICATION.
Improvements in an Electrolyte and Depolarizing Solution for
Voltaic Batteries. .
I, WILLIAM CROCKER QUINBY, residing at San Francisco, in the County of San
Francisco and State of California, United States of America, Electrical Engineer, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:.
My invention relates to certain improvements in Voltaic batteries, and its object is
the production of an electrolyte or solution containing a depolarizing element that will
absorb or engage the hydrogen as it is produced by the action of the Voltaic cell,
thereby producing an electric current, so called, the electro-motive force of which is
very constant. The electrolyte which I employ is anhydrous sulphate of the sesqui-
oxide [peroxide] of iron, dissolved in water or other equivalent liquid. This
anhydrous sulphate can be produced by the calcination of the pyrites of iron, and
afterwards combining it with anhydrous sulphuric acid. It can also be produced by
depriving the sulphate of iron green vitriol] of its acid, and calcining the oxide
thereof, and then combining the same with anhydrous sulphuric acid. . Nature,
however, has produced a similar sulphate of the sesqui-oxide of iron in quantity, and
it has been named by Mineralogists" Coquimbite.” It is this particular natural salt
that I prefer to employ.
The analysis I have made of this salt shows that in one hundred (100) parts, it
contains from thirty-five (35) to forty-five (45) per cent. of anhydrous sulphuric acid,
and from twenty-five (25) to thirty (30) per cent. of anhydrous sesqui-oxide of iron,
the balance being water of crystallization with traces of other metals, principally
sodium and aluminum, or the oxides thereof. Its color varies from sky-blue to
yellow, garnet, coffee-color, and almost black. The lighter colored pieces when
broken are translucent. Upon exposure to the light and in moist atmosphere, the
salt assumes a dark resinous appearance, and in time changes to a yellowish tint, not
unlike that of the yolk of an egg. When exposed to the heat of a furnace, all of the
different colors change to the yellowish hue mentioned above; and, as the heat

page_text: continues, the salt gives up its water of crystallization and finally its sulphuric acid,
leaving in the retort or furnace the sesqui-oxide of iron in the form of a fine powder.
The voltaic cell I employ may be composed of any of the usual metals used for such
purpose, such as zinc and carbon, zinc and copper, metallic iron and carbon, or
any other combination of metals as electrodes in contact with the electrolyte in a
containing vessel.
25
I will describe the action of this electrolyte in a <
one fluid voltaic cell with iron
and carbon employed as the electrodes; but it may be understood that it will apply to
a voltaic cell having any other materials as electrodes.
I will first describe my method of preparing my voltaic cell. In a containing
vessel of any kind, I place the electrodes of iron and carbon. I then dissolve the salt
in water or other liquid, and surround the electrodes therewith. No chemical or
galvanic action observable results until the electrodes are placed in contact or are
electrically connected, when the electric current, so called, is at once developed.
The cell develops
«
no gases that are observable, and there is no crystallizing
"crawling" within the cell, as is often the case in most voltaic batteries. The electric
current, so called, remains very constant, and I conclude that the hydrogen developed
by the decomposition of the electrolyte combines with or is retained by the sesqui-
oxide of iron in the solution.
or
My theory of the action of this cell is this: the sulphuric acid of the electrolyte
having a greater chemical affinity for the soluble electrode of the cell than it has for
the sesqui-oxide of iron with which it has been combined attacks the electrode, giving
up the sesqui-oxide of iron. The sesqui-oxide of iron next combines with or holds the
hydrogen, and is precipitated, and by gravitation settles to the bottom of the cell in
the form of a light powder. This powder, which I believe to be the sesqui-oxide of
iron, may be afterwards converted into a hydrated sulphate by combining it with the
sulphuric acid of commerce. This hydrated sulphate, being afterwards reduced with
water or other solvent, will form an electrolyte; the chemical and electrical action of
which is nearly the same as that of the natural salt, but of less efficiency, for the
reason that the oxide has already combined with a certain amount of hydrogen when
it was first liberated; and, there being traces of nitric acid in nearly all the sulphuric
acid of commerce, there is developed, by the combination of this trace of nitric acid
with the hydrated oxide, a certain amount of anhydrous sesqui-oxide which gives to it,.
as I believe, the only efficiency it possesses.
I do not, however, claim that there is anything new in this method of producing an
electrolyte for voltaic batteries included in the above-described mode of recovering the
sesqui-oxide; for I am aware that others have produced an electrolyte by treating a
solution of the sulphate of the protoxide of iron with sulphuric and nitric acids in
certain proportions and in a peculiar manner, the mixture producing at a certain
point in the reaction an anhydrous sulphate of the sesqui-oxide of iron.
<
I am also aware that a similar hydrated sulphate of the sesqui-oxide of iron has
been suggested as an electrolyte; also that the sesqui-oxide of iron has been used as a
depolarizer in combination with chlorine solutions.
All of these solutions differ from mine, because in these the sulphate of the sesqui-
oxide of iron is hydrated while mine is anhydrous, and because, having no hydrogen
in combination, its oxide is in a condition to combine with its full equivalent of
hydrogen whenever the proper conditions occur, as they do in my voltaic cell. But
whatever the theory may be, I have obtained, as demonstrated by experiment,
improved results by the use of the anhydrous sulphate.
While I have above described the action of my electrolyte in a "one fluid" voltaic
cell, I do not confine myself to its use in that way, for it may be employed in a two
fluid" voltaic cell with equal, if not better, results. When so employed, I place the
sulphate solution in a porous cup and in contact with the insoluble electrode of the
cell; the soluble electrode being in contact either with a weak solution of sulphuric
acid or with a chloride solution; or the soluble electrode may be placed in the porous
cup, and the depolarizing liquid in contact with the insoluble electrode outside.
I can also employ my electrolyte in what is generally known as a gravity cell,

page_text: placing the soluble electrode above the insoluble one, the soluble electrode being in a
solution of the sulphate of zinc, sulphate of magnesia or in a chloride solution, and the
insoluble electrode being in contact with my solution of the anhydrous sulphate of
the sesqui-oxide of iron. The different specific gravities of these solutions keep them
from mixing and prevent what is known as local action in the cell when the battery is
not in action.
I do not claim any particular form of cell. Nor do I confine myself to the use of
water as a solvent of the salt "coquimbite," for the reason that this salt is soluble in
hydrochloric acid, also in all chloride solutions which, being reduced with water,
would produce my electrolyte of equal if not greater efficiency.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. A voltaic cell, composed of an outer containing vessel with electrodes consisting
of different metals, or of carbon and a metal, in contact with an electrolyte or exciting
fluid composed of "coquimbite" or previously prepared anhydrous sulphate of the
sesqui-oxide of iron in solution, substantially as herein specified.
2. A voltaic cell, composed of an outer containing vessel, in combination with a
porous cup or diaphragm separating the electrodes of the cell, the insoluble electrode
being in contact with "Coquimbite" or previously prepared anhydrous sulphate of the
sesqui-oxide of iron in solution, and the soluble electrode being in contact with any
suitable solution, substantially as herein specified.
3. A voltaic cell, consisting of an outer containing vessel with electrodes of different
metals, or of carbon and a metal, the insoluble electrode being in contact with a
solution of "coquimbite" or previously prepared anhydrous sulphate of the sesqui-
oxide of iron in solution, and the soluble electrode in another solution, these two
solutions being of different specific gravities, substantially as herein specified.
4. An electrolyte or depolarizing solution, or both, for voltaic batteries, consisting
of "Coquimbite or previously prepared anhydrous sulphate of the sesqui-oxide of
iron in solution, substantially as herein specified.
WILLIAM CROCKER QUINBY.