Improvements in Electrolytes for the Deposition of Zinc, and for use in Secondary Batteries.
Year: 1897

page_text: Date of Application, 20th Jan., 1897
Complete Specification Left, 13th May, 1897-Accepted, 21st Aug., 1897
Improvements in Electrolytes for the Deposition of Zinc, and for use in
Secondary Batteries.
I, HENRY LEITNER of 207, Piccadilly, London, W. Philologist, do hereby declare
the nature of this invention to be as follows:-
This invention relates to improvements in connection with the deposition
of zinc for use in secondary batteries, and to the electrolyte to be employed in such
cells.
<
In a prior Application No. 24, 473 Nov. 2nd, 1896 made by me and entitled
Improvements in and connected with primary and secondary galvanic elements" an
electrolyte is employed composed of a solution of zinc sulphate, sulphuric acid and
alum, ammonium alum being preferably used. This electrolyte deposits a very
coherent and close layer of zinc.
My present invention is an improvement on this arrangement, and allows a still
more coherent layer of zinc to be obtained.
Further experiments have shown that the quality of the zinc depends greatly upon
the highly oxidised per-oxide plate, and that the said plate will always be in a highly
oxidised state even when the accumulator is discharged by surrounding it with an
electrolyte containing highly oxidised compounds. On an electrolyte of this kind
being employed the deposit of zinc is rendered much closer and more coherent than
it would otherwise have been. This is the case not only in the process of forming the
zine pole or pole of zinc alloy of the accumulator, but also at all stages of its work, and
it also allows of the acid and the zinc salts being employed in a more concentrated
form. This increases the efficiency of the accumulator, enabling a greater number of
ampere hours to be obtained from a given quantity of electrolyte and a given surface
of electrodes. Combined with this advantage there is also that of increasing the
efficiency of the lead per-oxide plate, owing to the highly oxidised compounds in the
electrolyte which not only surrounds the plate but also enters into all its pores,
assisting first in its oxidation and then in the depolarization of the plate, that is in
the oxidation of the nascent hydrogen evolved in discharging the cell.
The solution I propose to employ for this purpose is composed of the following
ingredients approximately in the proportions stated :-
Concentrated solution of zinc sulphate
Sulphuric acid (Pure)
Concentrated solution of manganese sulphate
Ammonium alum in a concentrated solution in which also a
further amount of zinc sulphate has been dissolved
50 parts,
10 parts,
-
10 parts,
-
30 parts.
If the zinc sulphate is not present in sufficient quantities more is added until the
solution approaches concentration. The solution may also be prepared in the following
manner 9 parts of water are taken with one part of concentrated sulphuric acid. One
part of concentrated solution of manganese sulphate is added to this and the resulting
solution is saturated with crystals of zinc sulphate and alum, preferably ammonium
071

page_text: alum. On the passage of a current, highly oxidised compounds such as permanganate
of ammonia, manganese per-oxide, and mixtures of the manganese oxides are
formed.
The presence of these compounds is shown by the coloration of the liquid round
the positive pole when a current is passed, a violet colour showing the presence of
permanganates.
When the electrolyte is used in the actual accumulator, in which the porous per-
oxide plate forms the positive pole, this coloration is less marked on account of the
said manganese compounds being formed within and on the positive plate, but it is
still quite distinct.
To prepare the zinc plate for the accumulator the lead or other base is placed in
the electrolyte prepared in the manner above described and the current is passed
through the solution in the usual manner. I prefer to employ at least two layers of
zinc, the first one being slightly amalgamated with mercury to thoroughly cleanse
all the pores.
The second layer is then deposited upon this, when the plate is ready for insertion
in the accumulator. The same solution is placed in the accumulator itself, throwing
down another deposit of zinc until the liquid is exhausted, when the cell is fully
charged.
With this cell the zinc can never be removed from the pole entirely, as the
electrolyte can only take up a certain quantity of the metal, i.e. the upper layer, or
the one last deposited, thus preventing any danger of the pole being injuriously
attacked. At the same time after the cell has been discharged to the proper extent,
a further current can be obtained at a lower potential being thus serviceable in case
of emergency even after discharging the supply of energy given to it on charging in
the ordinary manner.
A second battery constructed in this manner possesses some of the qualities of a
primary battery, the electrolyte itself acting not merely as a medium, but assisting
in the storage and development of electro-chemical energy.
Dated this 20th day of Janua1907
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.
Improvements in Electrolytes for the Deposition of Zinc, and for use in
Secondary Batteries.
.
I, HENRY LEITNER of 207, Piccadilly, London, W. Philologist, 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 :-
This invention relates to improvements in connection with the deposition of zinc
for use in secondary batteries, and to the electrolyte to be employed in such cells.
In a prior Application No. 24473 of 1896 made by me and entitled "Improvements
in and connected with primary and secondary galvanic elements an electrolyte is
employed composed of a solution of zinc sulphate, sulphuric acid and alum, ammonium
alum being preferably used. This electrolyte deposits a very coherent and close
layer of zinc. My present invention is an improvement on this arrangement, and
allows a still more coherent layer of zinc to be obtained.
"

page_text: Concentrated solution of zinc sulphate
Sulphuric acid (pure)
Concentrated solution of manganese sulphate
Ammonium alum in a concentrated solution in which also a
further amount of zinc sulphate has been dissolved
-
30 parts,
10 parts,
10 parts,
30 parts.
If the zinc sulphate is not present in sufficient quantities more is added until the
solution approaches concentration. The solution may also be prepared in the following
manner: 9 parts of water are taken with one part of concentrated sulphuric acid.
One part of concentrated solution of manganese sulphate is added to this and the
resulting solution is saturated with crystals of zinc sulphate and alum preferably
ammonium alum. On these ingredients being mixed together further compounds
are formed by the union of the manganese sulphate with the ammonium alum. On
the passage of a current these break up to form highly oxidised compounds such as
permanganate of ammonia, manganese per-oxide, and mixtures of the manganese
oxides.
The presence of these compounds is shown by the colouration of the liquid round
the positive pole when a current is passed, a violet colour showing the presence of
permanganates.
When the electrolyte is used in my working accumulator, in which the porous per-
oxide plate forms the positive pole, this colouration is less marked on account of the
said manganese compounds being formed within and on the positive plate, but it is
still quite distinct.
To prepare the zinc plate for the accumulator the lead or other base (preferably
constructed as in my specification No. 24473 of 1896 so as to exclude every possibility
of the generation of any local currents) is placed in the electrolyte prepared in the
manner above described and the current is passed through the solution in the usual
manner. I prefer to employ at least two layers of zinc, the first one being slightly
amalgamated with mercury to thoroughly close all the pores. The second layer is
then deposited upon this, when the plate is ready for insertion in the accumulator.
The same solution is placed in the accumulator itself throwing down another deposit
of zinc until the liquid is exhausted, when the cell is fully charged.
With this cell the zinc can never be removed from the pole entirely, as the
electrolyte can only take up a certain quantity of the metal, i.e., the upper layer or
the one last deposited thus preventing any danger of the pole being injuriously
attacked. At the same time after the cell has been discharged to the proper extent,
a further current can be obtained at a lower potential, being thus serviceable in case

page_text: of emergency even after discharging the supply of energy given to it on charging in
the ordinary manner.
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) In a secondary battery cell having for its positive electrode a porous lead per-
oxide plate of the kind hereinbefore described and for its negative electrode a zinc
element of the kind hereinbefore described the use of an electrolyte containing in
solution sulphuric acid, zinc sulphate, manganese sulpbate and, alum in about the
proportions above mentioned.
(2) The process hereinbefore described of forming the zinc element for a secondary
battery by electro deposition from a solution of the composition hereinbefore
described and defined by the preceding claiming clause.
Dated this 13th day of May 1897.
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.