▎ 摘　　要

NOVELTY - The method involves preparing porous flakes in a form of a sheet. A surface of a radical trapping particle is coated with the porous flakes, where a maximum value of diagonal length connecting an outer periphery of the porous flakes is about 400 nm or less. A non-porous material in the form of a sheet is used and selected from the group consisting of a high shear mixer, a ball mill, a resonant acoustic mixer (RAM) and a planetary mixer. A resonant acoustic vibrator is used, where thickness of a porous protective film is about 0.1-70 nanometer, radical trapping particle is selected from a group consisting of transition metals, ions, salts, oxides, nitrides and complexes and the porous protective film is a carbon-based protective film. The porous protective film is made of graphene. USE - Method for producing radical scavenger complex of a membrane-electrode assembly in a fuel cell (all claimed). ADVANTAGE - The method enables manufacturing the radical scavenger complex in a simple and cost-effective manner with improved chemical durability. DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a membrane-electrode assembly. 20Electrode 30Catalyst layer 40Electrode substrate 50Ion exchange membrane 100Membrane-electrode assembly