Abstract: A layered double hydroxide contains four elements of Ni, Fe, V, and Co, and further contains Mn as a fifth element.

Abstract: A layered double hydroxide is represented by the following formula (I): Ni2+1?(x+y+z)Fe3+xV3+yCo3+z(OH)2An?(x+y+z)/n·mH2O . . . (I). In one embodiment, in the formula (I), (x+y+z) is from 0.2 to 0.5, “x” represents more than 0 and 0.3 or less, “y” represents from 0.04 to 0.49, and “z” represents more than 0 and 0.2 or less.

Abstract: Provided is an air electrode/separator assembly including a hydroxide ion conductive separator including an inner space, a pair of catalyst layers covering both surfaces of the hydroxide ion conductive separator and containing a catalyst for an air electrode, a hydroxide ion conductive material, and an electron conductive material, a pair of gas diffusion electrodes provided on the pair of catalyst layers on a side opposite to the hydroxide ion conductive separator, and a water absorption/desorption layer provided so as to contact both of the pair of catalyst layers, having water absorbability and desorbability. One of the pair of catalyst layers is a catalyst layer for discharge and the other of the pair of catalyst layers is a catalyst layer for charge; and the hydroxide ion conductive separator, the catalyst layer, and the gas diffusion electrode are arranged vertically, and the water absorption/desorption layer is positioned below the catalyst layer.

Abstract: Provided is an air electrode/separator assembly including: a hydroxide ion conductive separator, an interface layer containing a hydroxide ion conductive material and an electron conductive material and covering one side of the hydroxide ion conductive separator; an air electrode layer provided on the interface layer and including a catalyst layer composed of a porous current collector and a layered double hydroxide (LDH) covering a surface thereof, and a water repellent porous layer covering a surface of the air electrode opposite to the hydroxide ion conductive separator.

Abstract: Provided is an air electrode/separator assembly including a hydroxide ion conductive separator, a catalyst layer including a catalyst for an air electrode, a hydroxide ion conductive material, an electron conductive material, a binder, and a humidity conditioning material and covering one side of the hydroxide ion conductive separator, and a gas diffusion electrode provided on the catalyst layer on a side opposite to the hydroxide ion conductive separator.

Abstract: A layered double hydroxide is represented by the following formula (I): Ni2+1?(x+y+z)Fe3+xV3+yCo3+z(OH)2An?(x+y+z)/n·mH2O . . . (I). In one embodiment, in the formula (I), (x+y+z) is from 0.2 to 0.5, “x” represents more than 0 and 0.3 or less, “y” represents from 0.04 to 0.49, and “z” represents more than 0 and 0.2 or less.