AIR ELECTRODE MATERIAL, AIR ELECTRODE, METAL-AIR BATTERY, AND FUEL CELL

PROBLEM TO BE SOLVED: To provide an air electrode material capable of forming, at a low cost, an air electrode catalyst layer with low volume resistivity.SOLUTION: An air electrode material according to the present invention contains a plurality of composite particles. Each of the composite particles is obtained by compositing: a core particle; and a plurality of coating particles for coating the surface of the core particle. The core particle is made of a material having catalytic activity for oxygen reduction reaction. Each of the coating particles is made of an electrically conductive material and is mechanically bonded to the core particle or another coating particle. The median diameter of the core particle is equal to or higher than 100 times but no greater than 1,000 times the average particle diameter of primary particles of the coating particles.SELECTED DRAWING: Figure 2 【課題】本発明は、低い製造コストで体積抵抗率の小さい空気極触媒層を形成することが可能な空気極材料を提供する。【解決手段】本発明の空気極材料は、複数の複合粒子を含み、前記複合粒子は、芯粒子と、前記芯粒子の表面を被覆する複数の被覆粒子とが複合化した粒子であり、前記芯粒子は、酸素還元反応に対する触媒活性を有する材料からなり、前記被覆粒子は、導電性を有する材料からなり、かつ、前記芯粒子又は他の被覆粒子と機械的に結合し、前記芯粒子のメディアン径は、前記被覆粒子の一次粒子の平均粒子径の１００倍以上１０００倍以下であることを特徴とする。【選択図】図２