Apollo Energy Systems, Incorporated

Martin Cifrain

Karl Kordesch

In a gas diffusion electrode the electrolyte must penetrate the pares of the electrode structure to a certain extent to establish the optimum interface between gas and liquid electrolyte, but it should not reach the gas-side of the electrodes. The best equilibrium of the so-called three phase zone (porous current collector-reaction gas-liquid electrolyte) is achieved by adequate wetproofing the porous structure with a polymeric substance as repellency agent. The polymeric substance serves also as a binder. During operation of the electrodes, the wetproofing material may lose its hydrophobicity for various reasons and the result is a penetration into the pores structures, reducing the interface between liquid and gas, notice by a loss of performance. By adding small amounts of wetproofing agents to the gases supplied to the electrodes, the original three-phase condition is maintained, or, if it is already partially degenerated, means and methods for its re-establishment are described. The invention claims substances and techniques for such maintenance and regeneration processes.

Additives to the gas supply of fuel cells with circulating electrolytes and means to regenerate used stacks

Fuel cell electrodes are described which comprise a non-woven network of conductive fibers, such as a carbon fleece, nickel foam sheet or stainless steel wool layer, plus additional activated carbon material, carrying one or more catalyst components and at least one polymeric substance as binder and/or repellancy agent to establish three zone interfaces (liquid-solid-liquid) or three phase interfaces (gas-liquid-solid). The electroactive catalyzed material is embedded into the conductive structure by specified deposition processes, such as coating, blading or spraying.

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Graz, Austria

Martin Cifrain