A cathode of a metal-air battery includes an electrically conductive metal oxide in a three-dimensional (3D) network structure, wherein the electrically conductive metal oxide of the three-dimensional network structure is in a form of a plurality of strands, wherein a strand of the plurality of strands has an aspect ratio in a range of about 10 to about 10.sup.7, and wherein the three-dimensional network structure has a porosity of about 70 volume percent to about 95 volume percent, based on a total volume of the three-dimensional network structure.

A cathode of a metal-air battery includes an electrically conductive metal oxide in a three-dimensional (3D) network structure, wherein the electrically conductive metal oxide of the three-dimensional network structure is in a form of a plurality of strands, wherein a strand of the plurality of strands has an aspect ratio in a range of about 10 to about 10.sup.7, and wherein the three-dimensional network structure has a porosity of about 70 volume percent to about 95 volume percent, based on a total volume of the three-dimensional network structure.

An electrode catalyst layer for electrochemical cells includes a first catalyst layer and a second catalyst layer. The first catalyst layer has a cell resistance measured at 80° C. and 40% RH lower than that of the second catalyst layer. The electrode catalyst layer for electrochemical cells is used with the first catalyst layer being disposed on an electrolyte membrane side relative to the second catalyst layer. It is preferable that a first catalytically active component contained in the first catalyst layer and a second catalytically active component contained in the second catalyst layer each independently contain at least one element selected from the group consisting of platinum, palladium, ruthenium, and iridium.

An electrode catalyst layer for electrochemical cells includes a first catalyst layer and a second catalyst layer. The first catalyst layer has a cell resistance measured at 80° C. and 40% RH lower than that of the second catalyst layer. The electrode catalyst layer for electrochemical cells is used with the first catalyst layer being disposed on an electrolyte membrane side relative to the second catalyst layer. It is preferable that a first catalytically active component contained in the first catalyst layer and a second catalytically active component contained in the second catalyst layer each independently contain at least one element selected from the group consisting of platinum, palladium, ruthenium, and iridium.

Provided is a metal negative electrode that has an excellent repeat resistance and is excellent in charge and discharge cycle characteristics even in a high charge and discharge rate, a method for fabricating the same, and a secondary battery using the metal negative electrode. The metal negative electrode is a metal negative electrode used for a secondary battery, which includes an active material portion, a current collector, and a non-electronically conductive reaction space divider. The active material portion forms metal during charging and forms an oxidation product of the metal during discharging. The metal is used as a negative-electrode active material. The current collector is electrically connected to the active material portion. The non-electronically conductive reaction space divider is integrally formed with or connected to the current collector and/or the active material portion. The reaction space divider has a plurality of electrolyte holder portions configured to hold a liquid electrolyte.

A battery assembly includes a battery that has a top surface surrounded by a circumferential edge; and a removable tab attached to the top surface. The removable tab includes a first tab end and an oppositely disposed second tab end; a gripping region disposed adjacent to the first tab end; and a battery cell attachment region disposed adjacent to the second tab end and attached to the top surface of the battery. The battery cell attachment region has first and second oppositely disposed sidewalls, wherein the second tab end is curved inwardly away from the circumferential edge of the battery such that a portion of the top surface of the battery is exposed between the second tab end and the circumferential edge of the battery

A battery assembly includes a battery that has a top surface surrounded by a circumferential edge; and a removable tab attached to the top surface. The removable tab includes a first tab end and an oppositely disposed second tab end; a gripping region disposed adjacent to the first tab end; and a battery cell attachment region disposed adjacent to the second tab end and attached to the top surface of the battery. The battery cell attachment region has first and second oppositely disposed sidewalls, wherein the second tab end is curved inwardly away from the circumferential edge of the battery such that a portion of the top surface of the battery is exposed between the second tab end and the circumferential edge of the battery

A battery includes an air cathode, an anode, an aqueous electrolyte, and a housing, wherein the housing includes one or more air access ports defining a total vent area; the battery exhibits a cell limiting current at 1.15V; a ratio of cell limiting current at 1.15 V to total vent area is greater than about 100 mA/mm.sup.2; and the aqueous electrolyte includes an amphoteric fluorosurfactant.

A battery includes an air cathode, an anode, an aqueous electrolyte, and a housing, wherein the housing includes one or more air access ports defining a total vent area; the battery exhibits a cell limiting current at 1.15V; a ratio of cell limiting current at 1.15 V to total vent area is greater than about 100 mA/mm.sup.2; and the aqueous electrolyte includes an amphoteric fluorosurfactant.

An apparatus which can include a cathode membrane for a power source is provided. The power source can include a current collector which can include a porous substrate. The power source can include a layer that coats the porous substrate to provide a catalyst for the cathode membrane. The layer can be formed from a mixture of hausmannite and cation intercalated manganese oxide.