摘要:
Apparatus and methods for regulating methanol concentration in a direct methanol fuel cell system without the need for a methanol concentration sensor. One or more operating characteristics of the fuel cell, such as the potential across the load, open circuit potential, potential at the anode proximate to the end of the fuel flow path or short circuit current of the fuel cell, are used to actively control the methanol concentration.
摘要:
Alkaline membrane fuel cells designed with silver cathode catalysts include a catalyst layer comprising silver metal nano-particles and an anion-conducting ionomer. The silver nano-particles are mixed with a solution of the ionomer to form a catalyst ink that is applied to an alkaline membrane to form an ultra-thin cathode catalyst layer on the membrane surface.
摘要:
An air CO2 filtration assembly or system is provided that includes CO2 filters or traps designed and configured with a limited, but high capacity, volume to maximize filtration/absorption of CO2 from an air stream supplied to an alkaline fuel cell to thereby minimize the CO2 level in the air stream fed into the fuel cell cathode. The CO2 filters or traps include at least one thermally regenerative CO2 chemical filter or trap arranged in a tandem configuration with a strongly bonding CO2 chemical filter or trap. The combination of the two types of filters or traps sequentially filter/absorb CO2 from the air stream and reduce the level of CO2 in the air stream fed into the cathode. The air CO2 filtration assembly or system may be used in conjunction with electrochemical purging of the alkaline fuel cell that enables removal of CO2 from the fuel cell by anodic decomposition of accumulated carbonate ions in the fuel cell anode and release of CO2 through the anode exhaust stream.
摘要:
Apparatus and methods for regulating methanol concentration in a direct methanol fuel cell system without the need for a methanol concentration sensor. One or more operating characteristics of the fuel cell, such as the potential across the load, open circuit potential, potential at the anode proximate to the end of the fuel flow path or short circuit current of the fuel cell, are used to actively control the methanol concentration.
摘要:
A conformable fuel cell is provided which includes a basic structure that provides flexibility while providing a high compression along the active surface of the fuel cell's membrane electrode assembly, which can be achieved by an injection-molded frame. A suitable fuel is delivered to the anode aspect of the fuel cell. Effective water management could also be provided by appropriate diffusion layers. The fuel cell can be contour-molded to a desired shape, or can be constructed of an array of flexibly connected individual fuel cells that overall have a curvilinear shape, or can be constructed as a pliable fuel cell that can be incorporated into an application device or an article of clothing.
摘要:
An electroplated element is formed to include an insulating substrate, a conducting polymer polymerized in situ on the substrate, and a metal layer deposited on the conducting polymer. In one application a circuit board is formed by polymerizing pyrrole on an epoxy-fiberglass substrate in a single step process and then electrodepositing a metal over the resulting polypyrrole polymer. No chemical deposition of the metal is required prior to electroplating and the resulting layer of substrate-polymer-metal has excellent adhesion characteristics. The metal deposition is surprisingly smooth and uniform over the relatively high resistance film of polypyrrole. A continuous manufacturing process is obtained by filtering the solution between successive substrates to remove polymer formed in the solution, by maintaining the solution oxidizing potential within selected limits, and by adding a strong oxidant, such as KMnO.sub.4 at periodic intervals to maintain a low sheet resistivity in the resulting conducting polymer film.
摘要:
A conducting polymer film with an improved space filling is formed on a metal electrode surface. A self-assembling monolayer is formed directly on the metal surface where the monolayer has a first functional group that binds to the metal surface and a second chemical group that forms a chemical bonding site for molecules forming the conducting polymer. The conducting polymer is then conventioonally deposited by electrochemical deposition. In one example, a conducting film of polyaniline is formed on a gold electrode surface with an intermediate monolayer of p-aminothiophenol.
摘要:
An electrochemical sensor electrode is formed from an electronic conductor coated with a casting solution containing a perfluorosulfonic acid ionomer and a selected enzyme. The selected enzyme catalyzes a reaction between a predetermined substance in a solution and oxygen to form an electrochemically active compound that is detected at the electronic conductor. The resulting perfluorosulfonic acid polymer provides a stable matrix for the enzyme for long lived enzyme activity, wherein only thin coatings are required on the metal conductor. The polymer also advantageously repels interfering substances from contacting the enzyme and contains quantities of oxygen to maintain a sensing capability during conditions of oxygen depletion in the sample. In one particular embodiment, glucose oxidase is mixed with the perfluorosulfonic acid ionomer to form an electrode for glucose detection.
摘要:
Proton exchange membrane (PEM) fuel cell performance with CO contamination of the H.sub.2 fuel stream is substantially improved by injecting O.sub.2 into the fuel stream ahead of the fuel cell. It is found that a surface reaction occurs even at PEM operating temperatures below about 100.degree. C. to oxidatively remove the CO and restore electrode surface area for the H.sub.2 reaction to generate current. Using an O.sub.2 injection, a suitable fuel stream for a PEM fuel cell can be formed from a methanol source using conventional reforming processes for producing H.sub.2.
摘要:
A device to produce electricity by a chemical reaction without the addition of liquid electrolyte comprises an anode electrode, a polymer membrane electrolyte fabricated to conduct hydroxyl (OH—) ions, the membrane being in physical contact with the anode electrode on a first side of the membrane, and a cathode electrode in physical contact with a second side of the membrane. The anode electrode and cathode electrode contain catalysts, and the catalysts are constructed substantially entirely from non-precious metal catalysts. Water may be transferred to the cathode side of the membrane from an external source of water.