Johnson Matthey Public Limited Company

Ballard Power Systems Corporation

Keith B Prater

David P Wilkinson

Henry H Voss

Graham Alan Hards

John Malcolm Gascoyne

Jonathan C Frost

David Thompsett

Thomas Robertson Ralph

David S Watkins

An electrode suitable for use in fuel cells, for example in solid polymer fuel cells, comprises a non-uniform electrode layer and has improved electrochemical performance.

Manufacture of electrodes

An electrode comprises a first catalytic component active at gas-phase reaction sites and a second catalytic component active at electrochemical reaction sites wherein each catalytic component is present either as a separate layer, or a single mixed layer or a combination of a separate layer and a single mixed layer. The electrode has an improved tolerance to poisons such as carbon monoxide and carbon dioxide.

Electrode

A solid polymer fuel cell electric power generation system removes a substantial portion of water accumulated at the cathode in the outlet fuel stream of the anode. The system permits the operation of a hydrogen/oxygen fuel cell in a dead-ended mode where substantially pure oxygen is employed as the oxidant supply or using low oxygen stoichiometry where a dilute oxidant source, such as oxygen-containing air, is employed as the oxidant supply. The system thereby eliminates the need for an oxygen recirculation pump in systems operating on substantially pure oxygen, and substantially reduces the parasitic load to pressurize the oxidant stream in systems operating on dilute oxidant streams.

Solid polymer fuel cell systems incorporating water removal at the anode

An electrochemical fuel cell is provided for converting a fuel reactant stream and an oxidant reactant stream to a reaction product stream and electrical energy. The fuel cell includes a membrane electrode assembly interposed between two separator layers. The separator layers are formed of thin electrically conductive sheet material which is substantially impermeable to the fuel and oxidant reactant streams. The membrane electrode assembly comprises first and second electrode layers formed of porous electrically conductive sheet material. The electrode layers have a catalyst associated therewith, and an ion exchange membrane is interposed between the first and second electrode layers. The electrode layers include passages, such as the interstitial spaces within the electrode material or grooves formed in the surface of the electrode material, for flowing a reactant stream between an inlet and outlet within the electrode layer. The incorporation of the reactant flow passages within the electrode material permits the use of thin, lightweight separator layers, thus providing higher power-to-volume and power-to-weight ratios than conventional fuel cells having reactant flow passages engraved, milled or molded in the separator plates.

Growing community of inventors

Vancouver, Canada

Keith B Prater