Year: 1888

page_text: We, LUDWIG MOND of Winnington Hall, Northwich, Cheshire, Manufacturing
Chemist, and Dr. CHARLES LANGER of 5 Redesdale Terrace, South Hampstead, N.W.
do bereby declare the nature of this invention to be as follows:-
:-
Gas batteries have hitherto been made by bringing two gases (capable of chemical
action upon each other, such as hydrogen-oxygen into contact with solid substances,
which have the power of absorbing or condensing these gases, such as platinum and
carbon and immersing these absorbing substances partly into a liquid electrolyte,
which keeps the two gases separated. All these batteries have proved very ineffective
and of no practical utility. In the earlier ones in which the absorbing substance
remained stationary in the liquid electrolyte the active surface was exceedingly
small and consequently the duty done by the battery was insignificant; in the
latter ones, in which the absorbing substance was alternately exposed to the gas
and to the liquid electrolyte by moving either the former or the latter the absorbing
substances become covered by a film of liquid which almost destroys their power of
absorbing gases.
In order to overcome both these difficulties we abandon the use of a liquid
electrolyte and substitute for it a solid porous substance which we moisten by a
liquid electrolyte so that the absorbing substance coming into contact with it
remains dry enough to retain its absorbing power for the gases to a sufficient
degree.
The porous substances used for this purpose must be non-conductors of electricity,
they must be unalterable by the other substances with which they come in contact in
the battery and must be impermeable to gases after they have been moistened. A
great many substances can be used for this purpose and we have found plates of
porous earthenware and plates of plaster of Paris, the latter preferably mixed with a
certain quantity of sulphate of barytes, to answer very well. If gases are used in
such a battery such as hydrogen or oxygen which by their chemical union produce a
liquid the action of the battery would gradually decrease on account of the liquid
formed soaking the condensing substance employed. To avoid this we employ the
gases dry or hot, so that they are capable of evaporating and taking up the water

page_text: or other liquid formed, and pass the gases through the battery in sufficient quantity
to carry off in this way in the form of vapour all the liquid produced in the battery.
The gases after having been deprived of the vapour so taken up, by drying or cooling
may be returned to the battery. Or we introduce into the battery in contact with
the gases but not with the electrolyte or the condensing substance, materials such as
sulphuric acid, calcium chloride etc., which absorb the moisture or other vapour
formed from the gases and thus maintain the gases in a state in which they can
constantly take up the water or other liquid formed in the battery and renew this
material either constantly or from time to time.
A convenient and simple way of constructing a battery according to our invention
is as follows:―
The porous plate mentioned above or its equivalent is fixed gas-tight in a frame of
a non-conducting material such as ebonite, the plate is then moistened by a liquid
electrolyte, say dilute sulphuric acid, and is covered on both sides with a substance
(or with a mixture of several substances) that has the power of condensing or
absorbing the gases to be employed. For this purpose the metals of the platinum
group more particularly in a finely divided state are pre-eminently suitable, but other
substances can also be used, amongst which we may name various kinds of finely
divided carbon and numerous metallic oxides and insoluble salts which are reduced by
hydrogen and other gases and can then take up again oxygen from the atmosphere,
such as the higher oxides of copper, tin, lead, manganese, and others. In some
cases it may be advantageous to use two different substances on the two sides of the
plate. We have obtained excellent results by using finely divided platinum obtained
by dissolving platinum in molten lead and subsequently dissolving the lead by
an acid. Over this absorbing substance we cover the plate on both sides by a good
conductor of electricity which is not affected by the materials used in the
battery, but which must, while itself in contact with the absorbing substance,
not prevent the gases from having access to it. For this purpose we find very
thin platinum or gold foil perforated by very numerous small holes or very fine
platinum or gold wire gauze very suitable. These conductors extend on one or more
sides of the frame beyond the porous plate and are here joined to or brought in
contact with wires to conduct the electricity formed away. Usually we imbed wires
into the frame or provide these frames with grooves, which we fill with an amalgam
which sets hard in the grooves over which the conductor extends and then join the
conducting wires to the amalgam.
We have found it advantageous but not necessary to cover the perforated foil or
wire gauze on the outside also with a thin layer of platinum black or other absorbing
substance. The frames with the plates so prepared are fixed gas-tight in a suitable
gas-tight vessel so that a gas-tight chamber is formed on each side of the plate.
These chambers must be provided with inlets and outlets for the gases to be employed.
A battery of any desired number of plates may be constructed by simply putting
frames of a gas-tight material such as ebonite between the frames carrying the
porous plates, so that chambers are formed with a porous plate on each side of them.
When atmospheric air is used as one of the gases one half of the chambers need
not be gas-tight and one side of the porous plates may be simply exposed to the
atmosphere. These batteries are specially suitable for producing electricity from
such gases as are obtained by the combustion of fuel or coke by means of steam
commonly called water-gas and by the incomplete combustion of fuel by means of air or
air and steam commonly called producer-gas, on the one side and of atmospheric
air on the other.
We do not confine ourselves to the particular construction of the battery described
or to the use of the materials named as many variations may be made in carrying
out our invention.
Dated th: 171L
1000

page_text: Improvements in Gas Batteries.
We, LUDWIG MOND of Winnington Hall, Northwich, in the County of Chester
Manufacturing Chemist, and Dr. CHARLES LANGER of 5 Redesdale Terrace, South
Hampstead N.W. in the County of Middlesex 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 :-
Gas batteries have hitherto been made by bringing two gases capable of chemical
action upon each other, such as hydrogen and oxygen, into contact with solid substances
which have the power of absorbing or condensing these gases, such as platinum and
carbon, and immersing these absorbing substances partly into a liquid electrolyte,
which keeps the two gases separated.
All these batteries have proved very ineffective, and of no practical utility. In
the earlier ones in which the absorbing substance remained stationary in the
liquid electrolyte, the active surface was exceedingly small, and consequently
the duty done by the battery was insignificant, in the latter ones in which
the absorbing substance was alternately exposed to the gas and to the liquid
electrolyte by moving either the former or the latter, the absorbing substances
become covered by a film of liquid which almost destroys their power of
absorbing gases.
In order to overcome both these difficulties, we abandon the use of a simple
liquid electrolyte, and substitute for it a solid porous substance, which we
impregnate by a liquid electrolyte, so that the absorbing substance coming into
contact with it, remains dry enough to retain its absorbing power for the gases to a
sufficient degree.
The porous substances used for this purpose must be non-conductors of electricity,
they must be unalterable by the other substances with which they come in contact
in the battery and must be impermeable to gases after they have been impregnated
with the electrolyte. A great many substances can be used for this purpose, amongst
which we may name paper, pasteboard, infusorial earth, sand, asbestos, clay, leather,
linen, flannel etcetera. If dry powders are used, we enclose these between
diaphragms or in a bag of parchment, paper or other suitable substance. We have,
however, found plates of porous earthenware and plates of plaster of Paris to be the
most handy.
These porous substances, we bring in contact with a substance or a mixture of
several substances, which have the power of absorbing or condensing the gases to he
employed. For this purpose the metals of the platinum group (platinum, palladium,
iridium, osnium, rhodium, ruthenium) more particularly in the form of a fine powder,
such as platinum black, are pre-eminently suitable; but other substances may be used,
amongst which we may name finely divided carbon. These absorbing substances are
relatively bad conductors of electricity, and in order to reduce the internal resistance
of the battery as far as possible, we bring them into frequent contact with a good

page_text: conductor, to carry away the electricity formed. This conductor must be in intimate
contact with the absorbing substance, but it must neither prevent the free access of
the gas to it, nor the contact of the absorbing substance with the electrolyte; and it
must also be unalterable by the substances used or produced in the battery. We find
very thin platinum, or gold foil or leaf perforated by very numerous and very small
holes, or very fine platinum or gold wire gauze, most suitable for this purpose. This
metallic foil leaf or gauze, we apply over the whole surface of the absorbing
substance, or we apply the foil leaf or gauze to the surface of the porous substance,
and put the absorbing substance on the outside of it in such a way that it fills up the
holes or open spaces in the foil or gauze, and thus comes in contact with the
porous substance; or we may put the absorbing substance on both sides of the foil
or gauze, or coat the foil or gauze with platinum black or its equivalent electrolitically.
The metallic foil or gauze is connected by convenient means to the poles of the
battery.
We thus obtain plates or vessels, which are fixed in gas-tight chambers, provided
with proper means of egress and ingress for the gases to be employed.
If gases are used in such a battery, such as hydrogen or oxygen, which by their
chemical union produce a liquid, the action of the battery would gradually decrease
on account of the liquid formed, soaking the absorbing substance employed. To
avoid this, we employ one or both of the gases dry or hot, so that they are capable
of evaporating and taking up. the water or other liquid formed and pass the gases
through the battery in sufficient quantity to carry off in this way in the form of
vapour all the liquid produced in the battery. The gases after having been
deprived of the vapour so taken up, by drying or cooling may be returned to the
battery.
When we employ hydrogen and atmospheric air, we find that all the water formed
can be removed by simply passing an excess of air through the battery without
previously drying or heating it, the heat produced in the battery itself assisting in
carrying the water from it."
We will now proceed to describe several ways for carrying out our invention;
reference being had to the accompanying drawings, in which,
Figure 1 is a section of a very small battery, consisting of a single plate, and
illustrates the manner of constructing the plates.
Figures 2, 3, & 4 show a convenient form of construction for a battery of
small or moderate size, Figures 2 & 3 being respectively sections on lines xx
and yy Figure 4, and Figure 4 being a plan with the top covering plate
removed.
Figures 5, 6, & 7 illustrate a convenient form of construction for a large battery,
Figure 5 being a section on line Figure 6, Figure 6 a sectional plan on line w, w
Figure 5, and Figure 7 an enlarged section of a portion of the battery, illustrating the
method of forming the plates thereof.
Figures 2 to 6 inclusive, are broken away in the centre to avoid repetition in the
lrawings.
Referring to Figures 1 to 4, for batteries of small or moderate size, we fix the
porous plates M mentioned above (say thin plates of earthenware or plaster of Paris)
in a frame R composed of a material non-conducting and impermeable to the gases,
(such as ebonite), by means of a suitable cement S, such as sealing wax. This frame
is provided on both sides all round the porous plates with narrow metallic conducting
strips A which are joined to the poles P'P¹ of the battery. We form these con-
ducting strips by providing the frame of ebonite all round porous plates at a distance
of about 2 mm. from these plates with grooves, which we fill with an easily fusible
alloy, with a hard setting amalgam, or with metallic wires or strips fixed in these
grooves. We employ the porous substance in small plates of square shape, of about
3 to 5 m. each side, and in case the surface of one porous plate is not sufficient to
generate the required strength of current, we cement several of them in the same
frame of ebonite, as shown in Figure 4. Then the porous plates are impregnated by a
liquid electrolyte (such as dilute sulphuric acid), and afterwards they are covered on

page_text: both sides with platinum or gold foil m Figure 1, which projects beyond the plates in
such a way that it is in metallic connection with the conducting strips A; that is to
say, that the foil covers the strips. To ensure that the metallic contact between the
foil and the conducting strips does not suffer from the oxydation of these latter, we
coat the foil in the places where it covers the strips with fused paraffin or a suitable
varnish.
The very fine metallic foil used contains already many small pores or holes, and
can be applied as it is, but it is advantageous to perforate it with a very large number
of very small holes, which can easily be done by mechanical means. The metallic
foil is put upon the porous plates, and made to adhere to them by gently rubbing over
its surface protected by a sheet of paper. Then the foil is covered with the absorbing
substance, by preference with the platinum black obtained by the reduction of chloride
of platinum in dilute alkaline solution by means of formic acid. We find a quantity
of two tenths of a gramme per square decimeter of surface to give a good result.
This platinum black we form into a paste with dilute sulphuric acid, and we apply
this paste with a brush upon the metallic foil. Part of the platinum black
penetrates through the holes of the foil and is brought into contact with the
porous plate, while part of it remains on the outside of the foil, where it is
rapidly dried and kept dry by the gases passing through the battery, and
consequently exerts upon the gases a very strong power of absorption.
Between the plates thus prepared, we place frames K of indiarubber or of
another suitable substance of the same dimensions in breadth and length as the
frames R of the ebonite, so as to form narrow and gas-tight chambers G, G¹, G³ etc.
between the frames of ebonite, which may be arranged one above the other as in
Figures 2 & 3, or side by side in such a way that after pressing them together with
end plates E É of a stiff material and screws E¹, we obtain between every two of the
ebonite plates gas-tight chambers G1 G2 G³ etc. These chambers are put in com-
munication with the gas-conducting tubes, and with one another by connections O H
which allow of hydrogen or its equivalent to be passed through the chambers G¹ G* G*
etc. and air or its equivalent through the chambers G G G etc. Each plate forms
an element of the battery, which can be combined at will with the others.
Referring to Figures 5, 6 & 7:-
For the construction of large batteries, we cast frames of a suitable metal (for
example, an alloy of lead and antimony) consisting of a broad edge R R, conducting
strips A and flaps F with the holes and channels O H, which form the inlets and
outlets for the gases to the gas-chambers G1, G2, G³ etc., or we cut such frames from
a metallic plate of suitable metal. The places which later will be in contact with
the electrolyte are covered with an insulating layer a Figure 7 impermeable to and
unattackable by the electrolyte (for example, a mixture of beeswax and resin or gutta
percha). Between two such frames we insert a thin sheet S₁ of porous material,
prepared by coating a piece of canvas or paper or other suitable substance, of the
full size of the frames with plaster of Paris or its substitute on both sides, and made
impervious round the edges by impregnating it with a mixture of beeswax and
resin, or other suitable insulating substance. We then fill the free spaces M
in the squares formed by the conducting strips with a porous substance, say plaster
of Paris, in such a way as to obtain a plate even on the outside.
These plates are then covered with the conducting and absorbing substances m,
Figure 7 in the same way as before described, and are united in a battery with the
interposition of frames K of india-rubber, paste-board, or other suitable substance, so
as to form the gas chambers, G.
Figure 5 shows a transverse section (on line z z figure 6) of a battery of seven plates,
and also the method of connecting the gas chambers with each other. The com-
munications between these chambers are made by cork or rubber washers or hollow
cylinders Q.
The first and last gas-chambers are formed by placing a plate J of paste
board or other non-conducting material at each side of the battery. The whole

page_text: battery is now placed between two metallic plates (Z Z Figure 5) say of
zinc, which project a certain distance beyond the plates forming the battery.
All the visible parts of the frames, not covered by these two zinc plates (Z¹ Z³),
are now well coated with a mixture of beeswax and resin or other suitable varnish,
and the space V left between the two zinc plates is then filled up with plaster of Paris,
so as to obtain a solid block with even surfaces. After the plaster of Paris has been
allowed to set and dry, we cover it with the zinc plates Z3, Z, Z, Z' and solder all
the zinc plates together, so as to obtain one solid, compact block, with no opening into
it, except the exits and entrances O H for the two gases.
The chemical action in the battery consists of the decomposition and new formation
of the electrolyte; if we employ, for instance, dilute sulphuric acid, this will be
decomposed into H, & SO. The hydrogen is carried by the current to the oxygen
side, and there combines with it by the aid of the platinum black, under the formation
of water. The SO, is carried towards the hydrogen side, and combines with this
again, forming sulphuric acid. By this action, an increasing accumulation of the
sulphuric acid on the hydrogen side takes place, and an accumulation of water on the
oxygen side, which produces a polarisation causing a diminution of the electro-motive
force of the battery. To counteract this polarisation, we change the gases from time
to time (for instance, say once an hour), so that the hydrogen is passed through the
chambers previously filled with oxygen and vice versa. By this means the sulphuric
acid accumulated on one side of the element is gradually taken back, and then
accumulated on the other side, and so on. The changing of the gases can be carried
out by automatic means, either in one chamber at a time, or through the whole
battery at once. In the first case, we are able by means of a commutator to
obtain from a single battery of a certain number of elements a constant
.current.
These gas batteries enable us to produce electricity at a very low cost by using on
the one side atmospheric air, on the other side the hydrogenic gases produced by
the action of steam upon incandescent coke, anthracite, iron etcetera, and by the
imperfect combustion of coal, coke or other carbonaceous substance by a mixture
of air and stean. These gases, however, must be very carefully purified,
and freed as much as possible from the carbon monoxide which they may
contain.
Even in using the hydrogen produced by the action of sulphuric acid upon
zinc, our batteries offer special advantages over the hydro-electric batteries. We
use atmospheric air as depolariser, and our battery is very compact, very
clean, does not give out any smell, and is easily and quickly set in and out
of action.
We do not limit ourselves to the details of the form and construction of the
batteries which we have described, nor to the use of the gases and substances
mentioned in this specification as being used in the construction and working
of the batteries. It is evident that the form and construction of the batteries can
be varied in a great many ways, and that a very large number of different substances,
can be employed to attain our end.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. The manufacture and use of a gas battery in which an electrolyte, liquid
near the ordinary temperature, is imbibed and absorbed by a porous
at or
substance.
2. The manufacture and use of a gas battery in which a porous substance impreg-
nated with an electrolyte, liquid at or near the ordinary temperature, is covered with
one or more substances capable of absorbing the gases to be employed, so that the
absorbing substances come into contact on the one side with the electrolyte, and on
the other side with one of the gases.

page_text: 3. The construction and use of a gas battery in which a porous substance impreg-
nated with an electrolyte is entirely or partly covered with one or more substances
capable of absorbing the gases used, and these absorbing substances are brought into
frequent contact over their whole surface with a good conductor of electricity,
permeable to the gases, so as to take and conduct away the electricity from
numerous points at small distances from each other, and thus to reduce the internal
resistance, and to increase the work done by the battery.
4. The counteracting of the polarisation of the battery by means of the periodical
interchange of the two gases used in the battery.
Dated this 16th dow of November 1888