The historical development, current status and future prospects of chlor-alkali electrolysis with oxygen depolarized cathodes (ODCs) are summarized. Over the last decades, membrane chlor-alkali technology has been optimized to such an extent that no substantial reduction of the energy demand can be expected from further process modifications. However, replacement of the hydrogen evolving cathodes in the classical membrane cells by ODCs allows for reduction of the cell voltage and correspondingly the energy consumption of up to 30%. This replacement requires the development of appropriate cathode materials and novel electrolysis cell designs. Due to their superior long-term stability, ODCs based on silver catalysts are very promising for oxygen reduction in concentrated NaOH solutions. Finite-gap falling film cells appear to be the technically most mature design among the several ODC electrolysis cells that have been investigated.

Chlor-alkali electrolysis with oxygen depolarized cathodes: history, present status and future prospects

Photoresists and associated processes for microlithography in the extreme, far, and near UV are disclosed. The photoresists in some embodiments comprise (a) a fluorine-containing copolymer comprising a repeat unit derived from at least one ethylenically unsaturated compound characterized in that at least one ethylenically unsaturated compound is polycyclic and at least one ethylenically unsaturated compound contains at least one fluorine atom covalently attached to an ethylenically unsaturated carbon atom; and (b) at least one photoactive component. In other embodiments, the photoresists comprise a fluorine-containing copolymer comprising a repeat unit derived from at least one polycyclic ethylenically unsaturated compound having at least one atom or group selected from the group consisting of fluorine atom, perfluoroalkyl group, and perfluoroalkoxy group, characterized in that the at least one atom or group is covalently attached to a carbon atom which is contained within a ring structure and separated from each ethylenically unsaturated carbon atom of the ethylenically unsaturated compound by at least one covalently attached carbon atom. The photoresists have high transparency in the extreme/far UV as well as the near UV, high plasma etch resistance, and are useful for microlithography in the extreme, far, and near ultraviolet (UV) region, particularly at wavelengths ≦365 nm. Novel fluorine-containing copolymers are also disclosed.

Photoresists, polymers and processes for microlithography

On the performance of membraneless laminar flow-based fuel cells

Provided is an air breathing direct methanol fuel cell pack including membrane electrode assemblies (MEAs) forming a plurality of single cells having an electrolyte membrane, a plurality of anodes on a first plane of the electrolyte membrane and a plurality of cathodes on a second plane of the electrolyte membrane correspondingly to the anodes, the second plane being opposed to the first plane, a fuel supply unit storing fuel fed to the anodes and having fuel supply plates with a plurality of fuel supply holes through which the fuel passes, and wicking sheets provided along a fuel supply path between the fuel supply plates and the MEAs, diffusing the fuel supplied through the fuel supply plates to supply the fuel to the anodes of the MEAs. fuel can be evenly supplied throughout MEAs, thereby attaining uniform power output, irrespective of a use posture of a cell pack. Also, current collectors of the present invention are of a mesh type so that current collection from all electrodes is allowed while allowing fuel supply. Further, since a gas communicating path for passage of byproducts is provided around the fuel supply unit and gas exhaust holes are provided on a wall body contacting the gas communicating path, byproducts can be effectively exhausted.

Air breathing direct methanol fuel cell pack

A passive direct oxidation fuel cell system, which uses a high concentration fuel such as neat methanol as a direct feed to an anode aspect of the fuel cell, is provided. The fuel cell includes a passive water management capability, achieved by the combined functions of controlled fuel dosing, effective push back of liquid water from the cathode through the membrane electrolyte by a hydrophobic microporous layer well bonded to the cathode catalyst and the use of a thin ionomeric membrane. The rate of fuel delivery is controlled by a passive fuel transport barrier. Carbon dioxide management techniques are also provided.

Direct oxidation fuel cell operating with direct feed of concentrated fuel under passive water management

The fuel utilization of a direct methanol fuel cell is enhanced for improved cell efficiency Distribution plates at the anode and cathode of the fuel cell are configured to distribute reactants vertically and laterally uniformly over a catalyzed membrane surface of the fuel cell A conductive sheet between the anode distribution plate and the anodic membrane surface forms a mass transport barrier to the methanol fuel that is large relative to a mass transport barrier for a gaseous hydrogen fuel cell In a preferred embodiment, the distribution plate is a perforated corrugated sheet The mass transport barrier may be conveniently increased by increasing the thickness of an anode conductive sheet adjacent the membrane surface of the fuel cell

Enhanced methanol utilization in direct methanol fuel cell

An air breathing direct methanol fuel cell is provided with a membrane electrode assembly (14), a conductive cathode assembly (18) that is permeable to air and directly open to atmospheric air, and a conductive anode assembly (16) that is permeable to methanol and directly concacting a liquid methanol source (12). Water loss from the cell is minimized by making the conductive cathode assembly (18) hydrophobic and the conductive anode assembly (16) hydrophilic.

Air breathing direct methanol fuel cell

A sealed ultracapacitor assembly is formed with first and second electrodes of first and second conducting polymers electrodeposited on porous carbon paper substrates, where the first and second electrodes each define first and second exterior surfaces and first and second opposing surfaces. First and second current collector plates are bonded to the first and second exterior surfaces, respectively. A porous membrane separates the first and second opposing surfaces, with a liquid electrolyte impregnating the insulating membrane. A gasket formed of a thermoplastic material surrounds the first and second electrodes and seals between the first and second current collector plates for containing the liquid electrolyte.

Conducting polymer ultracapacitor

A sensor outputs a signal related to a concentration of methanol in an aqueous solution adjacent the sensor. A membrane electrode assembly (MEA) is included with an anode side and a cathode side. An anode current collector supports the anode side of the MEA and has a flow channel therethrough for flowing a stream of the aqueous solution and forms a physical barrier to control access of the methanol to the anode side of the MEA. A cathode current collector supports the cathode side of the MEA and is configured for air access to the cathode side of the MEA. A current sensor is connected to measure the current in a short circuit across the sensor electrodes to provide an output signal functionally related to the concentration of methanol in the aqueous solution.

Methanol sensor operated in a passive mode

Inks are formulated for forming anode and cathode catalyst layers and applied to anode and cathode sides of a membrane for a direct methanol fuel cell. The inks comprise a Pt catalyst for the cathode and a Pt—Ru catalyst for the anode, purified water in an amount 4 to 20 times that of the catalyst by weight, and a perfluorosulfonic acid ionomer in an amount effective to provide an ionomer content in the anode and cathode surfaces of 20% to 80% by volume. The inks are prepared in a two-step process while cooling and agitating the solutions. The final solution is placed in a cooler and continuously agitated while spraying the solution over the anode or cathode surface of the membrane as determined by the catalyst content.

Shimshon Gottesfeld

Papers

Enhanced methanol utilization in direct methanol fuel cell

Air breathing direct methanol fuel cell

Conducting polymer ultracapacitor

Methanol sensor operated in a passive mode

Catalyst inks and method of application for direct methanol fuel cells