U.S. patent application number 17/055610 was filed with the patent office on 2021-07-22 for method for preparing flexible membrane-free and wire-shaped fuel celt.
This patent application is currently assigned to JIANGSU UNIVERSITY. The applicant listed for this patent is JIANGSU UNIVERSITY. Invention is credited to Jianning DING, Xinghao HU, Ningyi YUAN, Xiaoshuang ZHOU.
Application Number | 20210226226 17/055610 |
Document ID | / |
Family ID | 1000005693040 |
Filed Date | 2021-07-22 |
United States Patent
Application |
20210226226 |
Kind Code |
A1 |
DING; Jianning ; et
al. |
July 22, 2021 |
METHOD FOR PREPARING FLEXIBLE MEMBRANE-FREE AND WIRE-SHAPED FUEL
CELT
Abstract
A method for preparing a flexible membrane-free and wire-shaped
fuel cell is provided. A carbon nanotube sheet is twisted and
loaded with a catalyst to obtain a
(CNT)@Fe.sub.3[Co(CN).sub.6].sub.2 cathode electrode; the carbon
nanotube sheet is twisted and coated with a nickel powder to obtain
a CNT@nickel particle anode electrode; and the
(CNT)@Fe.sub.3[Co(CN).sub.6].sub.2 cathode electrode, the
CNT@nickel particle anode electrode, and a fuel electrolyte of
H.sub.2O.sub.2 are integrated in a silicone tube to obtain a
flexible membrane-free and wire-shaped fuel cell. The flexible
membrane-free and wire-shaped fuel cell of the present invention
can generate an open-circuit voltage of 0.88 V, while having very
good flexibility, and can be woven into textiles such as clothes,
thereby having great application prospects in the field of portable
energy supply.
Inventors: |
DING; Jianning; (Zhenjiang,
CN) ; ZHOU; Xiaoshuang; (Zhenjiang, CN) ;
YUAN; Ningyi; (Zhenjiang, CN) ; HU; Xinghao;
(Zhenjiang, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JIANGSU UNIVERSITY |
Zhenjiang |
|
CN |
|
|
Assignee: |
JIANGSU UNIVERSITY
Zhenjiang
CN
|
Family ID: |
1000005693040 |
Appl. No.: |
17/055610 |
Filed: |
June 18, 2019 |
PCT Filed: |
June 18, 2019 |
PCT NO: |
PCT/CN2019/091642 |
371 Date: |
November 16, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 4/9033 20130101;
H01M 8/002 20130101; H01M 4/9083 20130101; H01M 2004/021 20130101;
H01M 4/8657 20130101; H01M 4/8878 20130101 |
International
Class: |
H01M 8/00 20060101
H01M008/00; H01M 4/86 20060101 H01M004/86; H01M 4/90 20060101
H01M004/90; H01M 4/88 20060101 H01M004/88 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 11, 2019 |
CN |
201910206815.8 |
Claims
1. A method for preparing a flexible membrane-free and wire-shaped
fuel cell, comprising the following steps: (1) weighing reagents of
FeSO.sub.4.7H.sub.2O and K.sub.3[Co(CN).sub.6] and formulating the
reagents into aqueous solutions of FeSO.sub.4.7H.sub.2O and
K.sub.3[Co(CN).sub.6] respectively, mixing the aqueous solutions to
obtain a suspension under a magnetic stirring, filtering the
suspension to obtain a precipitate, washing the precipitate using
deionized water, and performing a low-temperature drying under
vacuum on the precipitate to obtain a catalyst
Fe.sub.3[Co(CN).sub.6].sub.2; (2) drawing a carbon nanotube sheet
out from a carbon nanotube forest, and stacking a first number of
layers of the carbon nanotube sheet, rolling the first number of
lavers of the carbon nanotube sheet into a cylindrical shape,
formulating the catalyst Fe.sub.3[Co(CN).sub.6].sub.2 in step (1)
and an ethanol solution into a catalyst solution with a
predetermined concentration, and then uniformly drip-coating the
catalyst solution onto the first number of layers of the carbon
nanotube sheet with the cylindrical shape, before twisting the
first number of lavers of the carbon nanotube sheet with the
cylindrical shape into a uniform (CNT)@Fe.sub.3[Co(CN).sub.6].sub.2
cathode electrode yarn by means of a motor; (3) spreading a second
number of layers of the carbon nanotube sheet on a glass sheet, and
then ultrasonically dispersing a nickel nanopowder in a
dimethylformamide (DMF) solution to prepare a dispersion, and then
uniformly drip-coating the dispersion onto the second number of
layers of the carbon nanotube sheet, before twisting the second
number of layers of the carbon nanotube sheet into a CNT@nickel
particle anode electrode yarn by means of the motor; (4) after the
CNT@nickel particle anode electrode yarn is naturally dried, by
means of two synchronous motors, coating a layer of polypropylene
(PP) monofilament on a surface of the CNT@nickel particle anode
electrode yarn to obtain a CNT@nickel@PP electrode; (5) weighing a
hydrogen peroxide solution, a perchloric acid solution, and a
sodium chloride salt solution to formulate a fuel electrolyte; and
(6) twisting and placing the (CNT)@Fe.sub.3[Co(CN).sub.6].sub.2
cathode electrode yarn and the CNT@nickel@PP electrode together,
into a silicone tube, and injecting the fuel electrolyte to the
silicone tube, so as to obtain a flexible membrane-free and
wire-shaped hydrogen peroxide fuel cell.
2. The method according to claim 1, wherein in step (1), the
aqueous solutions of FeSO.sub.4.7H.sub.2O and K.sub.3[Co(CN).sub.6]
have concentrations of 0.2 mol/L and 0.15 mol/L, respectively; the
mixing of the aqueous solutions is performed at a volume ratio of
1:1, and the magnetic stirring is performed at a rotational speed
of 240 revolutions per minute; the low-temperature drying under
vacuum is performed for a time of 6 to 10 hours at a temperature of
40.degree. C.
3. The method according to claim 1, wherein in step (2), the carbon
nanotube sheet has a length of 15 cm and a width of 2.5 cm, and the
first number of layers of the carbon nanotube sheet is 10; the
predetermined concentration of the catalyst solution is 5 mg/ml,
and an amount of the catalyst solution added dropwise is 1 ml; the
twisting by means of the motor is performed at a rotational speed
of 100 revolutions per minute for a time of 1 min.
4. The method according to claim 1, wherein in step (3), the carbon
nanotube sheet has a length of 15 cm and a width of 2.5 cm, and the
second number of layers of the carbon nanotube sheet is 10; in the
dispersion, a concentration of the nickel nan.opowder is 20 mg/ml,
and an amount of the dispersion added dropwise is 2 ml; the
twisting by means of the motor is performed at a rotational speed
of 100 revolutions per minute for a time of 1 min.
5. The method according to claim 1, wherein in step (4), the two
synchronous motors have a rotational speed of 50 revolutions per
minute, and the PP monofilament has a diameter of 100
micrometers.
6. The method according to claim 1, wherein in step (5), a
concentration of the hydrogen peroxide solution is 0.03 mol/L, a
concentration of the perchloric acid solution is 0.15 mol/L, a
concentration of the sodium chloride salt solution is 0.1 mol/L,
and the hydrogen peroxide solution, the perchloric, acid solution,
and the sodium chloride salt solution are mixed at a volume ratio
of 1:1:1.
7. The method according to claim 1, wherein the silicone tube in
step (6) has an inner diameter of 0.1 mm and a length of 10 to 20
cm.
Description
TECHNICAL FIELD
[0001] The present invention relates to the technical field of
wire-shaped fuel cells, and specifically to a method for preparing
a flexible membrane-free and wire-shaped fuel cell.
BACKGROUND
[0002] Wearable electronics have received much attention because of
their broad applications such as health monitoring, smart skin, and
sensors. To power these wearable electronic devices, flexible power
supplies are indispensable. Wire-shaped energy storage systems are
desirable for the wearable electronics, because fibers and/or yarns
are lightweight, flexible, and weavable. Therefore, tremendous
efforts have been made in the research of wire-shaped energy
storage devices, including wire-shaped lithium ion batteries,
supercapacitors, solar cells, and so on. However, due to
difficulties of wearable wire-shaped fuel cells in assembly,
membranes, electrolytes, catalysts, and other aspects, few research
has been done at present.
[0003] The fuel cell is a type of power sources having high
conversion efficiency and high energy density, which converts
chemical energy into electrical energy by reduction and oxidation
reactions on surfaces of a cathode and an anode. Thus, it is
necessary to implement flexible wire-shaped fuel cells in the
fields of flexible wearable electronics and textiles. However, a
flow field and a current collector of a conventional fuel cell are
usually rigid, heavy, and inflexible, such as a metal plate or
graphite plate, and cannot be integrated or woven into flexible
electronics or textiles. Meanwhile, a membrane structure of the
conventional fuel cell also lacks reliability and difficulty for
the design of wire-shaped devices. Therefore, it is desired to
design and manufacture a flexible wire-shaped fuel cell from the
following two aspects: one is preparing a flexible wire-shaped
collector electrode loaded with catalytic nanoparticles; and the
other is exploring the reaction mechanism of a fuel cell based on a
membrane-free single compartment.
SUMMARY
[0004] The technical problems to be solved in the present invention
are technical problems such as wire-shaping, miniaturization, and
portability of fuel cells, so as to provide a method for preparing
a flexible membrane-free and wire-shaped fuel cell.
[0005] The technical solution employed in the present invention to
solve the technical problems thereof is to load a catalyst on a
carbon nanotube yarn, and utilize the properties of hydrogen
peroxide as both a reductant fuel and an oxidant to enable a
cathode and an anode to be placed in the same compartment without a
membrane, and meanwhile, coat the anode with a spaced-apart yarn to
avoid a short-circuit therebetween.
[0006] The method for preparing the flexible membrane-free and
wire-shaped fuel cell includes the following steps:
[0007] (1) weighing FeSO.sub.4.7H.sub.2O and K.sub.3[Co(CN).sub.6]
reagents and formulating the reagents into aqueous solutions
respectively, mixing the aqueous solutions to obtain a suspension
under magnetic stirring, filtering the suspension to leave a
precipitate, washing the precipitate using deionized water, and
performing low-temperature drying under vacuum on the precipitate
to obtain a catalyst Fe.sub.3[Co(CN).sub.6].sub.2;
[0008] (2) drawing a carbon nanotube sheet out from a carbon
nanotube forest, and stacking a number of layers of the carbon
nanotube sheet which then are rolled into a cylindrical shape,
formulating the catalyst Fe.sub.3[Co(CN).sub.6].sub.2 in step (1)
and an ethanol solution into a catalyst solution with a certain
concentration, and then uniformly drip-coating the catalyst
solution onto the carbon nanotube sheet with the cylindrical shape,
before twisting into a uniform (CNT)@Fe.sub.3[Co(CN).sub.6].sub.2
cathode electrode yarn by means of a motor;
[0009] (3) spreading a number of layers of the carbon nanotube
sheet on a glass sheet, and then ultrasonically dispersing a nickel
nanopowder in a DMF solution to prepare a dispersion, and then
uniformly drip-coating the dispersion onto the carbon nanotube
sheet, before twisting into a CNT@nickel particle anode electrode
yarn by means of a motor;
[0010] (4) after the CNT@nickel particle anode electrode yarn is
naturally dried, by means of two synchronous motors, coating a
layer of polypropylene (PP) monofilament on a surface of the
CNT@nickel particle anode electrode yarn to obtain a CNT@nickel@PP
electrode;
[0011] (5) weighing a hydrogen peroxide solution, a perchloric acid
solution, and a sodium chloride salt to formulate a fuel
electrolyte; and
[0012] (6) twisting the (CNT)@Fe.sub.3[Co(CN).sub.6].sub.2 cathode
electrode yarn and the CNT@nickel@PP electrode together, placing
them into a silicone tube, and injecting the electrolyte thereto,
so as to obtain a flexible wire-shaped hydrogen peroxide fuel
cell.
[0013] As a preferred embodiment of the present invention, in step
(1), the aqueous solutions of FeSO.sub.4.7H.sub.2O and
K.sub.3[Co((N).sub.6] have concentrations of 0.2 mol/l and 0.15
mol/l, respectively. The mixing is performed at a volume ratio of
1:1, and the magnetic stirring is performed at a rotational speed
of 240 revolutions per minute. The low-temperature drying under
vacuum is performed for a time of 6 to 10 hours at a temperature of
40.degree. C.
[0014] As a preferred embodiment of the present invention, in step
(2), the carbon nanotube sheet has a length of 15 cm and a width of
2.5 cm, and the number of the layers is 10 layers. The
concentration of the catalyst is 5 mg/ml, and an amount of the
catalyst solution added dropwise is 1 ml. The twisting by means of
the motor is performed at a rotational speed of 100 revolutions per
minute for a time of 1 min.
[0015] As a preferred embodiment of the present invention, in step
(3), the carbon nanotube sheet has a length of 15 cm and a width of
2.5 cm, and the number of the layers is 10 layers. In the
dispersion, a concentration of the nickel nanopowder is 20 mg/ml,
and an amount of the dispersion added dropwise is 2 ml. The
twisting by means of the motor is performed at a rotational speed
of 100 revolutions per minute for a time of 1 min.
[0016] As a preferred embodiment of the present invention, in step
(4), the two synchronous motors have a rotational speed of 50
revolutions per minute, and the PP monofilament has a diameter of
100 micrometers.
[0017] As a preferred embodiment of the present invention, in step
(5), a concentration of the hydrogen peroxide is 0.03 mol/l, a
concentration of the perchloric acid solution is 0.15 mol/l, a
concentration of the sodium chloride solution is 0.1 mol/l, and the
three solutions are mixed at a volume ratio of 1:1:1.
[0018] As a preferred embodiment of the present invention, the
silicone tube in step (6) has an inner diameter of 0.1 mm and a
length of 10 to 20 cm.
[0019] The beneficial effects of the present invention are that the
method is simple, has a high efficiency and a good stability, and
facilitates large-scale industrial production.
[0020] The specific manifestations are as follows:
[0021] 1. Using the twisted yarn in which the carbon nanotube sheet
tightly coats the catalyst particles will maintain very good
flexibility and stability even during the bending process.
[0022] 2. The use of the insulating spaced-apart polypropylene yarn
ensures that the phenomenon of short-circuit due to the contact
between the cathode and the anode does not occur during bending in
the wire-shaped fuel cell.
[0023] 3. The wire-shaped fuel cell has weavability, which makes it
possible to apply a portable fuel cell to textiles.
[0024] 4. The encapsulation of the silicone tube ensures the acid
and alkali resistance and safety of the cell.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a scanning electron microscopy (SEM) image of an
anode electrode prepared in the present invention.
[0026] FIG. 2 is an SEM image of a cathode electrode prepared in
the present invention.
[0027] FIG. 3 is a schematic diagram of a wire-shaped fuel cell
prepared in the present invention.
[0028] FIG. 4 is a photograph of devices of the wire-shaped fuel
cell prepared in the present invention.
[0029] FIG. 5 is a graph showing performances of the wire-shaped
fuel cell prepared in the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0030] In order to make the aforementioned objectives, features,
and advantages of the present invention comprehensible, the present
invention will be described in further detail below in conjunction
with the drawings and specific embodiments.
[0031] As used herein, references to "one embodiment" or
"embodiments" are to be understood as describing particular
features, structures, or characteristics included in at least one
implementation of the present invention. Expressions "in one
embodiment" appearing at different places of this description do
not all refer to the same embodiment, or embodiments exclusive from
other embodiments alone or alternatively. In addition, it should be
noted that the mass fraction purity of FeSO.sub.4.7H.sub.2O,
K.sub.3[Co(CN).sub.6], and NaCl is 99.99% wt, and the concentration
of perchloric acid and ethanol (Analytical Reagent, AR)/hydrogen
peroxide is 30% wt. DMF represents N-methyl pyrrolidone (Analytical
Reagent, AR).
Example 1
[0032] (1) FeSO.sub.4.7H.sub.2O and K.sub.3[Co(CN).sub.6] reagents
are weighed and formulated into 20 ml of a 0.2 mol/L aqueous
solution and 20 ml of a 0.15 mol/L aqueous solution, respectively.
The FeSO.sub.4.7H.sub.2O aqueous solution is slowly added to the
K.sub.3[Co(CN).sub.6] aqueous solution to obtain a suspension under
magnetic stirring at 240 revolutions per minute. The suspension is
filtered to leave a precipitate, and the precipitate is
centrifugally washed 3 to 5 times using deionized water, and then
is dried for 8 h in a vacuum oven at 40.degree. C. to obtain a
catalyst Fe.sub.3[Co(CN).sub.6].sub.2.
[0033] (2) A carbon nanotube sheet is drawed out from a carbon
nanotube forest, the carbon nanotube sheet has a length of 15 cm
and a width of 2.5 cm, and 10 layers of the carbon nanotube sheet
are stacked, and then rolled into a cylindrical shape. The catalyst
in step (1) and an ethanol solution are formulated into a certain
amount of a 5 mg/mL solution, and then 1 ml of the catalyst
solution is measured and uniformly drip-coated onto the cylindrical
carbon sheet which then is twisted for 1 min by means of a motor at
100 revolutions per minute to obtain a uniform
(CNT)@Fe.sub.3[Co(CN).sub.6].sub.2 cathode electrode yarn.
[0034] (3) The carbon nanotube sheet is spread on a glass sheet,
the carbon nanotube sheet has a length of 15 cm and a width of 2.5
cm, and 10 layers of the carbon nanotube sheet are stacked. Then, a
nickel nanopowder is ultrasonically dispersed in a DMF solution to
prepare a 20 mg/ml dispersion, then 2 ml of the dispersion is
weighed and uniformly drip-coated onto the nano carbon sheet which
then is twisted for 1 min by means of a motor at 100 revolutions
per minute to obtain a CNT@nickel particle anode electrode
yarn.
[0035] (4) After the CNT@nickel particle yarn is naturally dried,
by means of two synchronous motors at a rotational speed of 50
revolutions per minute, a polypropylene (PP) monofilament having a
diameter of 100 micrometers is coated on a surface of the
CNT@nickel particle yarn to obtain a CNT@nickel@PP electrode.
[0036] (5) 0.3 mol/l hydrogen peroxide, 0.15 mol/l perchloric acid,
and 0.1 mol/l sodium chloride are weighed and formulated into a
mixed aqueous solution, where the three solutions are mixed at a
volume ratio of 1:1:1, obtaining a fuel electrolyte.
[0037] (6) The (CNT)@Fe.sub.3[Co(CN).sub.6].sub.2 and the
CNT@nickel@PP electrode are twisted together and placed into a
silicone tube, and the electrolyte is injected thereto, so as to
obtain a flexible wire-shaped hydrogen peroxide fuel cell.
Example 2
[0038] (1) FeSO.sub.4.7H.sub.2O and K.sub.3[Co(CN).sub.6] reagents
are weighed and formulated into 20 ml of a 0.20 mol/L aqueous
solution and 20 ml of a 0.15 mol/L aqueous solution, respectively.
The FeSO.sub.4.7H.sub.2O aqueous solution is slowly added to the
K.sub.3[Co(CN).sub.6] aqueous solution to obtain a suspension under
magnetic stirring at 240 revolutions per minute. The suspension is
filtered to leave a precipitate, and the precipitate is
centrifugally washed 3 to 5 times using deionized water, and then
is dried for 8 h in a vacuum oven at C to obtain a catalyst
Fe.sub.3[Co(CN).sub.6].sub.2.
[0039] (2) A carbon nanotube sheet is drawed out from a carbon
nanotube forest, the carbon nanotube sheet has a length of 15 cm
and a width of 3 cm, and 15 layers of the carbon nanotube sheet are
stacked, and then rolled into a cylindrical shape. The catalyst in
step (1) and an ethanol solution are formulated into a certain
amount of a 5 mg/mL solution, and then 1 ml of the catalyst
solution is measured and uniformly drip-coated onto the cylindrical
carbon sheet which then is twisted for 2 min by means of a motor at
100 revolutions per minute to obtain a uniform
(CNT)@Fe.sub.3[Co(CN).sub.6].sub.2 cathode electrode yarn.
[0040] (3) The carbon nanotube sheet is spread on a glass sheet,
the carbon nanotube sheet has a length of 15 cm and a width of 3
cm, and 10 layers of the carbon nanotube sheet are stacked. Then, a
nickel nanopowder is ultrasonically dispersed in a DMF solution to
prepare a 20 mg/ml dispersion, then 2 ml of the dispersion is
weighed and uniformly drip-coated onto the nano carbon sheet which
then is twisted for 1 min by means of a motor at 100 revolutions
per minute to obtain a CNT@nickel particle anode electrode
yarn.
[0041] (4) After the CNT@nickel particle yarn is naturally dried,
by means of two synchronous motors at a rotational speed of 25
revolutions per minute, a polypropylene (PP) monofilament having a
diameter of 100 micrometers is coated on a surface of the
CNT@nickel particle yarn to obtain a CNT@nickel@PP electrode.
[0042] (5) 0.3 mol/l hydrogen peroxide, 0.15 mol/l perchloric acid,
and 0.1 mol/l sodium chloride are weighed and formulated into a
mixed aqueous solution, where the three solutions are mixed at a
volume ratio of 1:1:1, obtaining a fuel electrolyte.
[0043] (6) The (CNT)@Fe.sub.3[Co(CN).sub.6].sub.2, and the
CNT@nickel@PP electrode are twisted together and placed into a
silicone tube, and the electrolyte is injected thereto, so as to
obtain a flexible wire-shaped hydrogen peroxide fuel cell.
Example 3
[0044] (1) FeSO.sub.4.7H.sub.2O and K.sub.3[Co(CN).sub.6] reagents
are weighed and formulated into 20 ml of a 0.20 mol/L aqueous
solution and 20 ml of a 0.15 mol/L aqueous solution, respectively.
The FeSO.sub.4.7H.sub.2O aqueous solution is slowly added to the
K.sub.3[Co(CN).sub.6] aqueous solution to obtain a suspension under
magnetic stirring at 240 revolutions per minute. The suspension is
filtered to leave a precipitate, and the precipitate is
centrifugally washed 3 to 5 times using deionized water, and then
is dried for 8 h at room temperature to obtain a catalyst
Fe.sub.3[Co(CN).sub.6].sub.2.
[0045] (2) A carbon nanotube sheet is thawed out from a carbon
nanotube forest, the carbon nanotube sheet has a length of 15 cm
and a width of 4 cm, and 15 layers of the carbon nanotube sheet are
stacked, and then rolled into a cylindrical shape. The catalyst in
step (1) and an ethanol solution are formulated into a certain
amount of a 5 mg/mL solution, and then 1 ml of the catalyst
solution is measured and uniformly drip-coated onto the cylindrical
carbon sheet which then is twisted for 1.5 min by means of a motor
at 100 revolutions per minute to obtain a uniform
(CNT)@Fe.sub.3[Co(CN).sub.6].sub.2 cathode electrode yarn.
[0046] (3) The carbon nanotube sheet is spread on a glass sheet,
the carbon nanotube sheet has a length of 15 cm and a width of 4
cm, and 10 layers of the carbon nanotube sheet are stacked. Then, a
nickel nanopowder is ultrasonically dispersed in a IMF solution to
prepare a 20 mg/ml dispersion, then 2 ml of the dispersion is
weighed and uniformly drip-coated onto the nano carbon sheet which
then is twisted for 1 min by means of a motor at 100 revolutions
per minute to obtain a CNT@nickel particle anode electrode
yarn.
[0047] (4) After the CNT@nickel particle yarn is naturally dried,
by means of two synchronous motors at a rotational speed of 50
revolutions per minute, a polypropylene (PP) monofilament having a
diameter of 100 micrometers is coated on a surface of the
CNT@nickel particle yarn to obtain a CNT@nickel@PP electrode.
[0048] (5) 0.3 mol/l hydrogen peroxide, 0.15 mol/l perchloric acid,
and 0.1 mol/l sodium chloride are weighed and formulated into a
mixed aqueous solution, where the three solutions are mixed at a
volume ratio of 1:1:1, obtaining a fuel electrolyte.
[0049] (6) The (CNT)@Fe.sub.3[Co(CN).sub.6].sub.2 and the
CNT@nickel@PP electrode are twisted together and placed into a
silicone tube, and the electrolyte is injected thereto, so as to
obtain a flexible wire-shaped hydrogen peroxide fuel cell.
[0050] The difference between the three examples lies in that
different widths and different numbers of layers ensure different
distributions of the loading and different mass ratios of the
loading, where Example 1 is the most preferred example.
[0051] From FIGS. 1 and 2, it can be seen that the loaded catalyst
is uniformly coated on the carbon nanotube yarn. FIG. 3 is a
schematic diagram of the prepared fuel cell, from which structural
parts of the device can be seen. FIG. 4 is a photograph of devices
of the actually manufactured wire-shaped fuel cell. FIG. 5 is a
graph showing performances of the finally obtained device. From
FIG. 5, it can be seen that the wire-shaped fuel cell can provide a
stable voltage of 0.89 V and a power density as high as 6.2 mW
cm.sup.-2.
* * * * *