In a case where an alkali aqueous solution is used as an electrolyte, provided are an oxygen catalyst excellent in catalytic activity and composition stability, an electrode having high activity and stability using this oxygen catalyst, and an electrochemical measurement method that can evaluate the catalytic activity of the oxygen catalyst alone. The oxygen catalyst is an oxide having peaks at positions of 2θ=30.07°±1.00°, 34.88°±1.00°, 50.20°±1.00°, and 59.65°±1.00° in an X-ray diffraction measurement using a CuKα ray, and having constituent elements of bismuth, ruthenium, sodium, and oxygen. An atom ratio O/Bi of oxygen to bismuth and an atom ratio O/Ru of oxygen to ruthenium are both more than 3.5.

Underwater apparatuses and methods of operating underwater apparatuses. The apparatus includes a power source such as an aluminum-water cell. Waste product from the power source may be channeled into various portions of the apparatus to adjust the buoyancy of the apparatus, the center of buoyancy of the apparatus, and/or the trim of the apparatus.

Underwater apparatuses and methods of operating underwater apparatuses. The apparatus includes a power source such as an aluminum-water cell. Waste product from the power source may be channeled into various portions of the apparatus to adjust the buoyancy of the apparatus, the center of buoyancy of the apparatus, and/or the trim of the apparatus.

Disclosed is a pouch type metal-air battery. In the pouch type metal-air battery, when the electrolyte inside the cell comes out of the electrode assembly by applying external pressure, the electrolyte does not reach the space partitioned by the gas diffusion layer, the electrode assembly and the exterior material, due to the step caused by the projection part of the gas diffusion layer. As such, a plurality of pores in the exterior material, which corresponds to the space, may not be blocked. Therefore, since oxygen selectively permeated from the exterior material flows into the gas diffusion layer, and flows into the electrode assembly through the diffusion portion of the gas diffusion layer, the contact resistance with pressure may improve and the initial driving conditions and driving reproducibility may be secured.

The invention includes a method of making a catalytic electrode for a metal-air cell in which a carbon-catalyst composite is produced by heating a manganese compound in the presence of a particulate carbon material to form manganese oxide catalyst on the surfaces of the particulate carbon, and then adding virgin particulate carbon material to the carbon-catalyst composite to produce a catalytic mixture that is formed into a catalytic layer. A current collector and an air diffusion layer are added to the catalytic layer to produce the catalytic electrode. The catalytic electrode can be combined with a separator and a negative electrode in a cell housing including an air entry port through which air from outside the container can reach the catalytic electrode.

Underwater apparatuses and methods of operating underwater apparatuses. The apparatus includes a power source such as an aluminum-water cell. Waste product from the power source may be channeled into various portions of the apparatus to adjust the buoyancy of the apparatus, the center of buoyancy of the apparatus, and/or the trim of the apparatus.

Underwater apparatuses and methods of operating underwater apparatuses. The apparatus includes a power source such as an aluminum-water cell. Waste product from the power source may be channeled into various portions of the apparatus to adjust the buoyancy of the apparatus, the center of buoyancy of the apparatus, and/or the trim of the apparatus.

An electrochemical cell and a method of operating the same. In accordance with various embodiments, the cell includes an anode, one or more cathodes opposite the anode defining a pathway there between. Chemical reactions allow the electrolyte to flow through the defined pathway without requiring a pumping device.

A metal-air battery including a cathode including a metal; an anode including a composite conductive material; a solid electrolyte layer between the cathode and the anode; and a vapor supplier configured to supply a vapor to the anode and the solid electrolyte layer.

Methods and systems for the electrochemical conversion of halogenated compounds are provided. In some embodiments, a method comprises converting a halogenated compound (e.g., fluorinated gas) to relatively non-hazardous products via oik* or more electrochemical reactions. The electrochemical reaction(s) may occur under relatively mild conditions (e.g., low temperature) and/or without the aid of a catalyst. In some embodiments, the electrochemical reaction may produce a relatively large amount of energy. In some such cases, systems, described herein, may be designed to facilitate the conversion of the halogenated compound (e.g., SF6, NF3) while harnessing (e.g.. storing, converting) the energy associated with the electrochemical reaction. System and methods described herein may be used in a wide variety of applications, including waste management (e.g.. environmental remediation, greenhouse gas mitigation), energy recovery (e.g., industrial energy recovery), and primary batteries (e.g., metal-gas batteries).