Hydrophilic treatment for hydrophobic gas electrodes

Claim 1

A method for increasing the effective internal reactive surface area of porous, alkaline electrolyte, hydrophobic-type gas electrodes which have a gas-exposed face, an electrolyte-exposed face and which comprise a conductive support and at least one layer of a sintered admixture of hydrophobic polymer particles and electrocatalytic particles, said method comprising the steps of: infiltrating said layer and coating said electrolyte-exposed face with an alcoholic solution comprising at least about 100 grams per liter of an alcohol-soluble, non-soap-forming, alkaline earth metal carboxylate; drying said electrode to remove the solvent from said solution and deposit said carboxylate within the interstices of said layer and on the electrolyte-exposed face of said electrode; and heating said alkaline earth metal carboxylate to decompose it into its corresponding alkaline earth metal oxide to provide an electrolyte wettable surface on said electrolyte-exposed face and a plurality of electrolyte wettable paths extending therefrom into the interstices of said layer.

Claim 2

A method for increasing the effective internal reactive surface area of porous, alkaline electrolyte, hydrophobic-type gas electrodes which have a gas-exposed face, an electrolyte-exposed face and which comprise a conductive support and at least one layer of a sintered admixture of hydrophobic polymer particles and electrocatalytic particles, said method comprising the steps of: infiltrating said layer and coating said electrolyte-exposed face with an alcoholic solution comprising at least about 100 grams per liter of at least one alkaline earth metal salt selected from the group consisting of the magnesium and calcium formates, acetates and citrates; drying said electrode to remove the solvent and deposit particles of said salt within the interstices of said layer and on the electrolyte-exposed face of said electrode; and heating said salt particles to decompose them into their corresponding oxides to provide an electrolyte wettable surface on said electrolyte-exposed face and a plurality of electrolyte wettable paths extending therefrom into the interstices of said layer.

Claim 3

A method for increasing the effective internal reactive surface area of porous alkaline electrolyte, hydrophobic-type gas electrodes which have a gas-exposed face, an electrolyte-exposed face, and which comprise at least one layer of a sintered admixture of hydrophobic polymer particles and electrocatalytic particles, said method comprising the steps of: infiltrating said layer and coating said electrolyte-exposed face with a solution comprising about 100 to about 300 grams per liter of Magnesium acetate in an isopropyl alcohol containing solvent; drying said electrode to remove said solvent and deposit said magnesium acetate within the interstices of said layer and on the electrolyte-exposed face of said electrode; and heating said electrode to a temperature of at least about 320* C. for a time sufficient to decompose said magnesium acetate to magnesium oxide to provide an electrolyte wettable surface on said electrolyte-exposed face of said electrode and a plurality of electrolyte wettable paths extending into the interstices of said layer.

Claim 4

A method for increasing the effective internal reactive surface area of porous, alkaline electrolyte, hydrophobic-type gas electrodes which comprise a conductive support and at least one layer of a sintered admixture of hydrophobic polymer particles and electrocatalytic particles, said method comprising the steps of: infiltrating said layer with an alcoholic solution of an alcohol-soluble, non-soap-forming, alkaline earth metal carboxylate; drying said electrode to remove the solvent from said solution and deposit said carboxylate within the interstices of said layer; and converting said alkaline earth metal carboxylate to its corresponding alkaline earth metal hydroxide to provide a plurality of electrolyte wettable paths extending throughout said layer.

Claim 5

A method for increasing the effective internal reactive surface area of porous, alkaline electrolyte, hydrophobic-type gas electrodes which have a gas-exposed face, an electrolyte-exposed face and which comprise a conductive support and at least one layer of a sintered admixture of hydrophobic polymer particles and electrocatalytic particles, said method comprising the steps of: infiltrating said layer and coating said electrolyte-exposed face with an alcoholic solution comprising at least about 100 grams per liter of an alcohol-soluble, non-soap-forming, alkaline earth metal carboxylate; drying said electrode to remove the solvent from said solution and deposit said carboxylate within the interstices of said layer and on the electrolyte-exposed face of said electrode; and immersing said electrode into a solution of an alkali metal hydroxide to convert said alkaline earth metal carboxylate to its corresponding alkaline earth metal hydroxide to provide an electrolyte wettable surface on said electrolyte-exposed face and a plurality of electrolyte wettable paths extending therefrom into the interstices of said layer.

Claim 6

A method for increasing the effective internal reactive surface area of porous, alkaline electrolyte, hydrophobic-type gas electrodes which have a gas-exposed face, an electrolyte-exposed face and which comprise a conductive support and at least one layer of a sintered admixture of hydrophobic polymer particles and electrocatalytic particles, said method comprising the steps of: infiltrating said layer and coating said electrolyte-exposed face with an alcoholic solution comprising at least about 100 grams per liter of at least one alkaline earth metal salt selected from the group consisting of the magnesium and calcium formates, acetates and citrates; drying said electrode to remove the solvent and deposit particles of said salt within the interstices of said layer and on the electrolyte-exposed face of said electrode; and immersing said electrode into a solution of an alkali metal hydroxide to convert said salt particles to their corresponding hydroxides to provide an electrolyte wettable surface on said electrolyte-exposed face and a plurality of electrolyte wettable paths extending therefrom into the interstices of said layer.

Claim 7

A method for increasing the effective internal reactive surface area of porous alkaline electrolyte, hydrophobic-type gas electrodes which have a gas-exposed face, an electrolyte-exposed face, and which comprise at least one layer of a sintered admixture of hydrophobic polymer particles and electrocatalytic particles, said method comprising the steps of: infiltrating said layer and coating Said electrolyte-exposed face with a solution comprising about 100 to about 300 grams per liter of magnesium acetate in an isopropyl alcohol containing solvent; drying said electrode to remove said solvent and deposit said magnesium acetate within the interstices of said layer and on the electrolyte-exposed face of said electrode; and immersing said electrode into a solution of an alkali metal hydroxide to convert said magnesium acetate to magnesium hydroxide to provide an electrolyte wettable surface on said electrolyte-exposed face of said electrode and a plurality of electrolyte wettable paths extending into the interstices of said layer.