3YSZ typically refers to zirconia stabilized with 3 mol% yttria (Y₂O₃). In SOFC applications, it is classified as partially stabilized zirconia. Its function is significantly different from that of 8YSZ, which is a fully stabilized electrolyte.

3YSZ substrates are primarily used as structural support materials in solid oxide fuel cell research. They provide high mechanical strength and excellent fracture toughness for thin electrolyte and functional layers. Due to their superior structural stability, 3YSZ substrates are widely used as platforms for anode and cathode material development.