| abstract |
Provided is an electrode catalyst ink composition capable of forming an electrode catalyst layer without causing cracks. An electrode catalyst ink composition comprising metal oxide-based electrode catalyst particles, an electrolyte, and a mixed liquid medium, the mixed liquid medium (set the total amount of the mixed liquid medium as 100% by mass) comprising: 40 to 85% by mass of Water; 5 to 30% by mass of the water-soluble solvent (A), when the evaporation rate of water at 25°C is set to 1, the evaporation rate is 2.0 or less, and the solubility parameter (SP value) is 9 or more; and 10 The monohydric alcohol (B) of -30% by mass has an evaporation rate greater than 2.0 when the evaporation rate of water at 25°C is 1, and has 3 or less carbon atoms. |