U.S. patent application number 17/411244 was filed with the patent office on 2021-12-09 for reversible manganese dioxide electrode, method for the production thereof, the use thereof, and rechargeable alkaline-manganese battery containing said electrode.
The applicant listed for this patent is ZENTRUM FUR SONNENENERGIE- UNC WASSERSTOFF-FORSCHUNG BADEN-WURTTEMBERG. Invention is credited to Jerry Bamfo ASANTE, Olaf BOSE, Ludwig JORISSEN.
Application Number | 20210384501 17/411244 |
Document ID | / |
Family ID | 1000005798848 |
Filed Date | 2021-12-09 |
United States Patent
Application |
20210384501 |
Kind Code |
A1 |
JORISSEN; Ludwig ; et
al. |
December 9, 2021 |
REVERSIBLE MANGANESE DIOXIDE ELECTRODE, METHOD FOR THE PRODUCTION
THEREOF, THE USE THEREOF, AND RECHARGEABLE ALKALINE-MANGANESE
BATTERY CONTAINING SAID ELECTRODE
Abstract
The invention relates to a reversible manganese dioxide
electrode, comprising an electrically conductive carrier material
having a nickel surface, a nickel layer made of spherical nickel
particles adhering to each other and having an inner pore structure
applied to the carrier material, and a manganese dioxide layer
applied to the nickel particles, wherein the manganese dioxide
layer is also present in the inner pore structure of the nickel
particle. The invention also relates to a method for producing such
a manganese dioxide electrode, the use thereof in rechargeable
alkaline-manganese batteries, and a rechargeable alkaline-manganese
battery containing a manganese dioxide electrode according to the
invention.
Inventors: |
JORISSEN; Ludwig; (Neu-Ulm,
DE) ; ASANTE; Jerry Bamfo; (Ulm, DE) ; BOSE;
Olaf; (Neu-Ulm, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ZENTRUM FUR SONNENENERGIE- UNC WASSERSTOFF-FORSCHUNG
BADEN-WURTTEMBERG |
Stuttgart |
|
DE |
|
|
Family ID: |
1000005798848 |
Appl. No.: |
17/411244 |
Filed: |
August 25, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16770463 |
Jun 5, 2020 |
11133500 |
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PCT/EP2019/082056 |
Nov 21, 2019 |
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17411244 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 4/366 20130101;
H01M 4/29 20130101; H01M 4/0452 20130101; H01M 4/502 20130101; H01M
10/26 20130101; H01M 10/44 20130101 |
International
Class: |
H01M 4/50 20060101
H01M004/50; H01M 4/04 20060101 H01M004/04; H01M 4/29 20060101
H01M004/29; H01M 4/36 20060101 H01M004/36; H01M 10/26 20060101
H01M010/26; H01M 10/44 20060101 H01M010/44 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 6, 2018 |
DE |
10 2018 131 168.0 |
Claims
1-14. (canceled)
15. A reversible manganese dioxide electrode, comprising: an
electrically conductive carrier material; a nickel layer formed on
the electrically conductive carrier material, the nickel layer
comprising spherical nickel particles adhered to one another, the
nickel layer having an inner pore structure; and a manganese
dioxide layer formed on the nickel layer and at least partially
filling the inner pore structure thereof.
16. The reversible manganese dioxide electrode according to claim
15, wherein the nickel layer has a thickness between 10 .mu.m and
1000 .mu.m.
17. The reversible manganese dioxide electrode according to claim
16, wherein the thickness of the nickel layer is between 20 .mu.m
and 500 .mu.m.
18. The reversible manganese dioxide electrode according to claim
17, wherein the thickness of the nickel layer is between 50 .mu.m
and 200 .mu.m.
19. The reversible manganese dioxide electrode according to claim
18, wherein the thickness of the nickel layer is about 100
.mu.m.
20. The reversible manganese dioxide electrode according to claim
15, wherein each of the spherical nickel particles has an average
particle size of between 0.1 .mu.m and 25 .mu.m.
21. The reversible manganese dioxide electrode according to claim
20, wherein the average particle size is between 1 .mu.m and 10
.mu.m.
22. The reversible manganese dioxide electrode according to claim
21, wherein the average particle size is between 2 .mu.m and 6
.mu.m.
23. The reversible manganese dioxide electrode according to claim
22, wherein the average particle size is between 3 .mu.m and 4
.mu.m.
24. The reversible manganese dioxide electrode according to claim
15, wherein the electrically conductive carrier material is
selected from the group consisting of a nickel sheet, a nickel
foil, and a nickel-coated carrier material.
25. The reversible manganese dioxide electrode according to claim
15, wherein the electrically conductive carrier material comprises
a nickel sheet.
26. The reversible manganese dioxide electrode according to claim
15, wherein the manganese dioxide layer has a thickness between 1
.mu.m and 50 .mu.m.
27. The reversible manganese dioxide electrode according to claim
26, wherein the thickness of the manganese dioxide layer is between
2 .mu.m and 30 .mu.m.
28. The reversible manganese dioxide electrode according to claim
27, wherein the thickness of the manganese dioxide layer is between
5 .mu.m and 20 .mu.m.
29. The reversible manganese dioxide electrode according to claim
28, wherein the thickness of the manganese dioxide layer is between
5 .mu.m and 10 .mu.m.
30. A rechargeable alkaline-manganese battery, comprising: a
current collector; a reversible manganese dioxide electrode
surrounding the current collector, wherein the reversible manganese
dioxide electrode comprises: an electrically conductive carrier
material; a nickel layer formed on the electrically conductive
carrier material, the nickel layer comprising spherical nickel
particles adhered to one another, the nickel layer having an inner
pore structure; and a manganese dioxide layer formed on the nickel
layer and at least partially filling the inner pore structure
thereof; a separator layer; and a negative electrode, wherein the
separator layer is sandwiched between the negative electrode and
the reversible manganese dioxide electrode.
31. The rechargeable alkaline-manganese battery according to claim
30, wherein the nickel layer has a thickness between 10 .mu.m and
1000 .mu.m.
32. The rechargeable alkaline-manganese battery according to claim
30, wherein each of the spherical nickel particles has an average
particle size of between 0.1 .mu.m and 25 .mu.m.
33. The rechargeable alkaline-manganese battery according to claim
30, wherein the electrically conductive carrier material is
selected from the group consisting of a nickel sheet, a nickel
foil, and a nickel-coated carrier material.
34. The rechargeable alkaline-manganese battery according to claim
30, wherein the manganese dioxide layer has a thickness between 1
.mu.m and 50 .mu.m.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a reversible manganese dioxide
electrode made of an electrically conductive carrier material
having a nickel surface, a nickel layer made of spherical nickel
particles having an internal pore structure applied to the carrier
material and a manganese dioxide layer applied to the nickel
particles, a method for the production of such a manganese dioxide
electrode, the use thereof in rechargeable alkaline battery
systems, in particular alkaline-manganese batteries, and a
rechargeable alkaline-manganese battery containing such a
reversible manganese dioxide electrode, in particular an
alkaline-manganese battery also designated as alkali-mangenese
battery.
TECHNICAL BACKGROUND AND PRIOR ART
[0002] The alkaline-manganese battery or the alkaline-manganese
cell is an important electrochemical energy store from the family
of zinc manganese dioxide cells. The alkaline-manganese cell is one
of the primary elements, i.e. the non-rechargeable batteries,
although it is generally rechargeable to an extent. Versions
intended for recharging are referred to as "RAM cells"
(Rechargeable Alkaline Manganese), which count as secondary
elements (accumulators).
[0003] In the alkaline-manganese cell, also referred to as zinc
manganese oxide cell, manganese dioxide is used for the positive
electrode, wherein an aqueous solution of potassium hydroxide is
usually used as the alkaline electrolyte. The cathode (positive
electrode) is on the outside and is a metal cup coated on the
inside with manganese dioxide. The anode (negative electrode) in
the middle of the cell usually consists of zinc powder.
[0004] The cyclization of manganese dioxide electrodes was limited
under these conditions to a few cycles with poor performance. The
interest in manganese dioxide as a positive electrode material for
alkaline electrolytes is due to the high specific capacity, the low
price, and the low toxicity thereof. However, the low cyclability
due to the high irreversible losses during charging has hitherto
prevented the use of manganese dioxide as a positive electrode
material in rechargeable batteries having alkaline
electrolytes.
[0005] RAM cells can deliver approximately 10-20 full cycles (at
100% depth of discharge) or approximately 200 cycles at a low depth
of discharge of 10-20%. After 10 full cycles (100% depth of
discharge) using a discharge current rate of 0.08 C, only 60% of
the initial capacity is available. In addition, they can only be
used for very low discharge current rates between 0.03 and 0.6 C.
RAM cells are therefore only suitable for low-current applications,
such as clocks or remote controls. They are not suitable for
high-current applications such as digital cameras, cordless tools,
or as drive batteries in model vehicles and can be damaged in the
process. Furthermore, an increase in the discharge current rate
from 0.03 C to 0.5 C already halves the available capacity. RAM
cells must not be over-discharged in order not to lose their
recharge ability. If RAM cells are discharged up to a final
discharge voltage of 1.42 V per cell, the achievable number of
cycles is a few 100 s. With a discharge of up to 1.32 V, the number
of cycles is reduced to a few 10 s. In the event of a further
discharge, RAM cells can no longer be charged or can only be
charged with a significantly reduced capacity.
OBJECT OF THE INVENTION
[0006] The invention has for its object to provide a reversible
manganese dioxide electrode and a method for its production, while
avoiding the disadvantages of the prior art, which can be used as a
working electrode in rechargeable alkaline battery systems, in
particular alkaline-manganese cells. Likewise, a rechargeable
alkaline-manganese battery, in particular an alkaline-manganese
battery, is to be provided, which allows high discharge current
rates and has good cycle stability without suffering significant
capacity losses.
SUMMARY OF THE INVENTION
[0007] The aforementioned objects are achieved according to the
invention by a reversible manganese dioxide electrode according to
claim 1, a process for the production thereof according to claim 7,
the use thereof according to claim 13, and a rechargeable
alkaline-manganese battery according to claim 14.
[0008] Preferred or particularly expedient embodiments of the
subject matter of the application are specified in the
subclaims.
[0009] The invention thus relates to a reversible manganese dioxide
electrode, comprising an electrically conductive carrier material
having a nickel surface, a nickel layer made of spherical nickel
particles adhering to each other and having an inner pore structure
applied to the carrier material and a manganese dioxide layer
applied to the nickel particles, wherein the manganese dioxide
layer is also present in the inner pore structure of the nickel
particle.
[0010] The invention also relates to a method for producing such a
reversible manganese dioxide electrode, comprising the following
steps: [0011] a) Providing an electrode structure made of an
electrically conductive carrier material having a nickel surface
and a nickel layer made of spherical, porous nickel particles
adhering to each other and having an inner pore structure applied
to the carrier material, [0012] b) Depositing a
manganese(II)-hydroxide layer onto the nickel particles of the
nickel layer from a manganese(II)-salt solution, [0013] c)
Oxidizing the manganese(II)-hydroxide layer to a manganese dioxide
layer.
[0014] The invention also relates to the use of the reversible
manganese dioxide electrode according to the invention as a working
electrode in rechargeable alkaline battery systems, in particular
alkaline-manganese batteries or secondary alkaline-manganese
cells.
[0015] The invention finally relates to a rechargeable
alkaline-manganese battery, in particular an alkaline-manganese
battery or a secondary alkaline-manganese cell, containing a
reversible manganese dioxide electrode according to the invention
as the working electrode.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The manganese dioxide electrode according to the invention,
which is intended in particular for alkaline aqueous electrolytes,
is characterized in that when used as a working electrode in an
alkali-manganese cell with an alkaline electrolyte, discharge
current rates of up to 150 C are possible, wherein the cell itself
has no discernible loss of capacity after 100 cycles.
[0017] The electrodes according to the invention show an initial
formation reaction, in which approximately 30 cycles are required
to develop the full capacity. The manganese dioxide electrodes
according to the invention are therefore suitable as positive
electrodes for use in rechargeable alkaline battery systems, in
particular alkaline-manganese batteries.
[0018] The manganese dioxide electrode according to the invention
is constructed in such a way that a nickel layer made of spherical
nickel particles adhering to one another and having an inner pore
structure is provided on an electrically conductive carrier
material having a nickel surface, preferably a nickel plate. A
manganese dioxide layer is then applied to the nickel particles of
the nickel layer, wherein the manganese dioxide layer is also
present in the inner pore structure of the nickel particles. The
manganese dioxide layer can partially or completely fill the inner
pore structure, so that the inner surface of the pores is partially
or completely covered with manganese dioxide. While the nickel
particles of the nickel layer have an inner pore structure, the
nickel layer also has an outer pore structure, which is defined by
the voids between the individual nickel particles. This outer pore
structure can also be partially covered with manganese dioxide, in
particular in surface areas which lie opposite the carrier
material.
[0019] The electrically conductive carrier material having a nickel
surface can be not only a nickel sheet, but also a nickel foil or
nickel-coated carrier material, including nickel-coated metal or
plastic foils, such as steel foils, or nickel-coated non-woven or
fabric textiles. Such electrically conductive fabrics based on
nickel-coated nonwoven and fabric textiles are commercially
available and consist, for example, of polyester, which are made
electrically conductive by a nickel coating. This means that these
fabrics have electrical properties that are just as good as those
of metal having great material flexibility and light weight.
[0020] According to the invention, it has been shown that by using
such a nanostructured nickel electrode as the basic electrode
structure and applying a manganese dioxide layer to such a
nanostructured nickel electrode, reversible manganese dioxide
electrodes having the aforementioned advantageous properties can be
obtained. Nanostructured nickel electrodes are understood to mean
nickel electrodes which have a nickel layer composed of spherical,
porous nickel particles adhering to one another, wherein the nickel
particles have an inner pore structure with a high inner surface.
The pores have a diameter of a few 100 nm, preferably up to 100
nm.
[0021] Such nickel electrodes and methods for their production are
described in WO 2017/085173 A1. The method for producing such
nickel electrodes comprises the following steps: [0022] a)
providing spherical nickel hydroxide particles, [0023] b) partially
reducing the spherical nickel hydroxide particles in a reducing
atmosphere at elevated temperatures in order to achieve partially
reduced, spherical Ni/NiO particles, [0024] c) producing a paste
from the Ni/NiO particles obtained and an organic and/or inorganic
binder and, if appropriate, further auxiliaries, [0025] d) applying
the paste as a coat on one or both sides of an electrically
conductive carrier material having a nickel surface, in particular
a nickel sheet, and [0026] e) tempering the coated carrier material
in a reducing atmosphere at elevated temperatures.
[0027] In the manganese dioxide electrode according to the
invention, the nickel layer preferably has a thickness in the range
from 10-1000 .mu.m, more preferably 20-500 .mu.m, even more
preferably 50-200 .mu.m, and particularly preferably about 100
.mu.m, before the manganese dioxide layer is applied.
[0028] The spherical nickel particles of the nickel layer
preferably have an average particle size of 0.1-25 .mu.m, more
preferably of 1-10 .mu.m, even more preferably of 2-6 .mu.m, and
particularly preferably of 3-4 .mu.m.
[0029] In the method for producing a manganese dioxide electrode
according to the invention, a nickel electrode as described above
is initially provided as the basic electrode structure. A
manganese(II)-hydroxide layer from a manganese(II)-salt solution is
then deposited on the nickel particles of the nickel layer. The
manganese(II)-hydroxide layer is preferably deposited
electrochemically in a manner known per se, wherein a manganese
nitrate solution is preferably used as the manganese(II)-salt
solution. For example, potentiostatic deposition takes place
against an Ag/AgCl reference electrode from an aqueous manganese
nitrate solution. The amount of electricity required for the
deposition can be calculated according to Faraday's law in a manner
known per se. This process reduces the nitrate ion to nitrite ion,
forming hydroxide ions. The hydroxide ions formed precipitate the
manganese(II)-hydroxide on the nickel particles.
[0030] A manganese dioxide layer can of course also be deposited
from other manganese compounds, for example from potassium
permanganate.
[0031] In a further step, the manganese(II)-hydroxide layer is then
oxidized to a manganese dioxide layer. Known oxidizing agents can
be used here, such as selected from the group consisting of
hydrogen peroxide, potassium peroxodisulfate, potassium
permanganate, sodium hypochlorite, dichloroxide, oxygen, such as
atmospheric oxygen and ozone. In the process according to the
invention, the oxidation is preferably carried out by means of an
alkaline solution of hydrogen peroxide, particularly preferably an
aqueous solution of potassium hydroxide and hydrogen peroxide. A
1:1 solution of 0.1 M KOH and 0.1 M H.sub.2O.sub.2 is particularly
suitable, for example.
[0032] The manganese dioxide layer of the manganese dioxide
electrode according to the invention preferably has a thickness in
the range from 1 to 50 .mu.m, more preferably from 2 to 30 .mu.m,
even more preferably from 5 to 20 .mu.m, and particularly
preferably from 5 to 10 .mu.m. These thicknesses refer to the
so-called equivalent layer thickness, which is to be understood as
the layer thickness that would result on a completely planar
carrier material. In the case of electrochemical deposition of the
manganese(II)-hydroxide layer as an intermediate stage, a
corresponding amount of manganese(II)-hydroxide per 1 cm.sup.2 of
electrode area is required to achieve a desired equivalent layer
thickness of manganese dioxide. The amount of electricity required
for the deposition of the corresponding basis weight of
manganese(II)-hydroxide can be calculated in a manner known per se
according to Faraday's law. For example, loading the electrode
carrier material with 2.54 mg/cm.sup.2 Mn(OH).sub.2 arithmetically
results in an equivalent layer thickness of rounded 5 .mu.m
MnO.sub.2. A loading of the electrode carrier material with 5.08
mg/cm.sup.2 Mn(OH).sub.2 corresponds to an equivalent layer
thickness of rounded 10 .mu.m MnO.sub.2.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 shows a SEM image of the surface of a nickel
electrode used as the basic electrode structure for producing a
manganese dioxide electrode according to the invention at a
magnification of five hundred times;
[0034] FIG. 2 shows an SEM image of the nickel electrode shown in
FIG. 1 at a magnification of ten thousand times;
[0035] FIG. 3 shows an SEM image of the surface of a manganese
dioxide electrode according to the invention having a 5 .mu.m-thick
manganese dioxide layer at a magnification of five hundred
times;
[0036] FIG. 4 shows an SEM image of the manganese dioxide electrode
shown in FIG. 3 at a magnification of three thousand times;
[0037] FIG. 5 shows a SEM image of the surface of a manganese
dioxide electrode according to the invention having a 10
.mu.m-thick manganese dioxide layer at a magnification of five
hundred times;
[0038] FIG. 6 shows an SEM image of the manganese dioxide electrode
shown in FIG. 5 at a magnification of three thousand times;
[0039] FIG. 7 shows discharge diagrams of manganese dioxide
electrodes according to the invention having a manganese dioxide
layer thickness of approximately 5 .mu.m;
[0040] FIG. 8 shows discharge diagrams of manganese dioxide
electrodes according to the invention having a manganese dioxide
layer thickness of approximately 10 .mu.m.
PREFERRED EMBODIMENTS AND EXEMPLARY EMBODIMENTS
Example 1
Production of a Manganese Dioxide Electrode having a MnO.sub.2
Layer Thickness of Approximately 5 .mu.m
[0041] In the first step, an approximately 5 .mu.m Mn(OH).sub.2
layer is electrochemically deposited on nanostructured nickel
electrodes by potentiostatic deposition at -1.1 V against the
Ag/AgCl reference electrode from a freshly prepared, aqueous 1M
Mn(NO.sub.3).sub.2 solution. The amount of current for the
deposition of 2.54 mg Mn(OH).sub.2 per 1 cm.sup.2 electrode area
results according to Faraday's law in 1.567 mAh. After the
Mn(OH).sub.2 layer has been produced, the electrode is rinsed
thoroughly with deionized water.
[0042] In the second step, the electrode thus produced is oxidized
to MnO.sub.2 with a 1:1 solution of 0.1 M KOH and 0.1
MH.sub.2O.sub.2 for 10 to 12 hours at room temperature.
Mathematically, this results in 2.48 mg MnO.sub.2 per 1 cm.sup.2.
With a density of 5.03 g/cm.sup.3 for MnO.sub.2, this results in an
equivalent layer thickness of 4.93 .mu.m MnO.sub.2 and
approximately 5 .mu.m rounded. After the MnO.sub.2 layer has been
produced, the electrode is rinsed thoroughly with deionized water
and then dried at 40.degree. C. for 5 hours.
Example 2
Production of a Manganese Dioxide Electrode with MnO.sub.2 Layer
Thickness of about 10 .mu.m
[0043] In the first step, an approximately 10 .mu.m Mn(OH).sub.2
layer is electrochemically deposited on nanostructured nickel
electrodes by potentiostatic deposition at -1.1 V against the
Ag/AgCl reference electrode from a freshly prepared, aqueous 1M
Mn(NO.sub.3).sub.2 solution. The amount of current for the
deposition of 5.08 mg Mn(OH).sub.2 per 1 cm.sup.2 electrode area
results according to Faraday's law in 3.134 mAh. After the
Mn(OH).sub.2 layer has been produced, the electrode is rinsed
thoroughly with deionized water.
[0044] In the second step, the electrode thus produced is oxidized
to MnO.sub.2 with a 1:1 solution of 0.1 M KOH and 0.1
MH.sub.2O.sub.2 for 10 to 12 hours at room temperature.
Mathematically, this results in 4.96 mg MnO.sub.2 per 1 cm.sup.2.
This results in an equivalent layer thickness of 9.86 .mu.m
MnO.sub.2 and approximately 10 .mu.m rounded. After the MnO.sub.2
layer has been produced, the electrode is rinsed thoroughly with
deionized water and then dried at 40.degree. C. for 5 hours.
Example 3
Cyclization and Discharge of the Electrodes According to the
Invention
[0045] Three samples each of the electrodes produced in Example 1
(layer thickness approximately 5 .mu.m) and Example 2 (layer
thickness approximately 10 .mu.m) were discharged with different
current densities up to 400 mA/cm.sup.2. The discharge diagrams
obtained in this way are shown in FIGS. 7 and 8.
[0046] It can be seen that the electrodes produced undergo an
initial formation reaction of approximately 30 cycles before they
reach their full capacity.
[0047] The MnO.sub.2 electrodes with a coating thickness of 5 .mu.m
(example 1 and FIG. 7) have a maximum capacity of 1.27 mAh/cm.sup.2
and can be discharged up to 200 mA/cm.sup.2 or 157 C without
significant loss of capacity (FIG. 7).
[0048] The MnO.sub.2 electrodes with a coating thickness of 10
.mu.m (example 2 and FIG. 8) have a maximum capacity of 1.92
mAh/cm.sup.2 and can be discharged up to 50 mA/cm.sup.2 or 26 C
without significant loss of capacity (FIG. 8).
[0049] The fact that doubling the MnO.sub.2 layer thickness does
not lead to doubling the surface capacity is due to the fact that
the nickel electrodes used as the base electrode structure already
have their own capacity of approximately 0.55 mAh/cm.sup.2. Taking
this capacity of the nickel electrode into account results in a
rounded capacity for the manganese dioxide layer of approximately
1.4 mAh per 10 .mu.m layer thickness.
[0050] The discharges were each carried out on a 1 cm.sup.2
electrode in 6.0 M KOH.
* * * * *