Abstract: An electrochemical cell includes an air electrode in flow communication with a storage tank containing an aqueous solution of hydrogen peroxide, a lithium electrode, a catalyst layer in contact with the air electrode or a gas diffusion layer associated with the air electrode, and a separator layer in contact with the lithium electrode and catalyst layer. The catalyst layer includes a catalyst for two electron reversible oxygen reduction. The catalyst comprises gold, and a cobalt coordination complex or polymer thereof. The cobalt coordination complex comprises a cobalt ion chelated by a tetradentate organic chelating ligand.

Abstract: An electrochemical cell includes an air electrode in flow communication with a storage tank containing an aqueous solution of hydrogen peroxide, a lithium electrode, a catalyst layer in contact with the air electrode or a gas diffusion layer associated with the air electrode, and a separator layer in contact with the lithium electrode and catalyst layer. The catalyst layer includes a catalyst for two electron reversible oxygen reduction. The catalyst comprises gold, and a cobalt coordination complex or polymer thereof. The cobalt coordination complex comprises a cobalt ion chelated by a tetradentate organic chelating ligand.

Abstract: A catalyst is provided for the two electron reduction of oxygen. The catalyst can be reversible or near-reversible. The catalyst comprises a gold and a cobalt coordination complex, i.e., N,N?-bis(salicylidene)ethylene-diaminocobalt (II) (cobalt salen) or a derivative thereof. The cobalt coordination complex can be polymerized to form a film, for example, via electropolymerization, to cover a gold surface. Also provided are metal-air batteries, fuel cells, and air electrodes that comprise the catalyst, as well as methods of using the catalyst, for example, to reduce oxygen and/or produce hydrogen peroxide.

Abstract: An electrochemical device includes an anode, a cathode, and a separator interposed between the anode and cathode. The separator includes an anion conductive membrane having a porous substrate having hydrophilic moieties bonded thereto to increase water availability in a vicinity of ionogenic sites contributing to conductivity of the membrane in a presence of aqueous phases imbibed therein.

Abstract: A catalyst is provided for the two electron reduction of oxygen. The catalyst can be reversible or near-reversible. The catalyst comprises a gold and a cobalt coordination complex, i.e., N,N?-bis(salicylidene)ethylene-diaminocobalt (II) (cobalt salen) or a derivative thereof. The cobalt coordination complex can be polymerized to form a film, for example, via electropolymerization, to cover a gold surface. Also provided are metal-air batteries, fuel cells, and air electrodes that comprise the catalyst, as well as methods of using the catalyst, for example, to reduce oxygen and/or produce hydrogen peroxide.

Abstract: An electrochemical flow type battery may include at least one electrode and a separator. The electrode may include carbon fibers and/or carbon particles, and has an internal surface area density of at least 1 m2/g. The separator may separate an anode side and a cathode side of the battery. A flat surface of the electrode directly contacts a surface of the separator.

Abstract: A polymer electrolyte fuel cell (PEFC) is designed to operate on a reformate fuel stream containing oxygen and diluted hydrogen fuel with CO impurities. A polymer electrolyte membrane has an electrocatalytic surface formed from an electrocatalyst mixed with the polymer and bonded on an anode side of the membrane. An anode backing is formed of a porous electrically conductive material and has a first surface abutting the electrocatalytic surface and a second surface facing away from the membrane. The second surface has an oxidation catalyst layer effective to catalyze the oxidation of CO by oxygen present in the fuel stream where at least the layer of oxidation catalyst is formed of a non-precious metal oxidation catalyst selected from the group consisting of Cu, Fe, Co, Tb, W, Mo, Sn, and oxides thereof, and other metals having at least two low oxidation states.

Abstract: A method is provided for operating a fuel cell at high voltage for sustained periods of time. The cathode is switched to an output load effective to reduce the cell voltage at a pulse width effective to reverse performance degradation from OH adsorption onto cathode catalyst surfaces. The voltage is stepped to a value of less than about 0.6 V to obtain the improved and sustained performance.

Abstract: A polymer electrolyte fuel cell (PEFC) is designed to operate on a reformate fuel stream containing oxygen and diluted hydrogen fuel with CO impurities. A polymer electrolyte membrane has an electrocatalytic surface formed from an electrocatalyst mixed with the polymer and bonded on an anode side of the membrane. An anode backing is formed of a porous electrically conductive material and has a first surface abutting the electrocatalytic surface and a second surface facing away from the membrane. The second surface has an oxidation catalyst layer effective to catalyze the oxidation of CO by oxygen present in the fuel stream where at least the layer of oxidation catalyst is formed of a non-precious metal oxidation catalyst selected from the group consisting of Cu, Fe, Co, Tb, W, Mo, Sn, and oxides thereof, and other metals having at least two low oxidation states.

Abstract: A method is provided for operating a fuel cell at high voltage for sustained periods of time. The cathode is switched to an output load effective to reduce the cell voltage at a pulse width effective to reverse performance degradation from OH adsorption onto cathode catalyst surfaces. The voltage is stepped to a value of less than about 0.6 V to obtain the improved and sustained performance.

Abstract: An enzyme electrode is prepared with a composite coating on an electrical conductor. The composite coating is formed from a casting solution of a perfluorosulfonic acid polymer, an enzyme, and a carbon supported catalyst. The solution may be cast directly on the conductor surface or may be formed as a membrane and applied to the surface. The perfluorosulfonic acid ionomer formed from the casting solution provides an insoluble biocompatible protective matrix for the enzyme and acts to retain the enzyme for long term availability in the electrode structure. The carbon supported catalyst provides catalytic sites throughout the layer for the oxidation of hydrogen peroxide from the enzyme reactions. The carbon support then provides a conductive path for establishing an electrical signal to the electrical conductor.

Abstract: 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.