Highly textured dense Ca_3−xY_xCo₄O_9+δ (0 ≤ x ≤ 0.3) samples were fabricated by combining sol−gel process with spark plasma sintering (SPS). Y³⁺ substitution for Ca²⁺ simultaneously increased the Seebeck coefficient and reduced the thermal conductivity. The latter was attributed to the increase in lattice anharmonicity, structural distortion, and grain boundary area, which enhanced the phonon scattering. Ca_2.7Y_0.3Co₄O_9+δ showed the largest dimensionless figure-of-merit (ZT = 0.194) at 1073 K because it had the largest Seebeck coefficient and the lowest thermal conductivity. This ZT value was 55 % larger than that of undoped Ca₃Co₄O₉ (0.125 at 1073 K). Therefore, Y³⁺ substitution, sol−gel powder synthesis, and SPS are highly effective for enhancing the thermoelectric properties of Ca₃Co₄O₉.

高度纹理化的Ca致密_{3- X} ý _X共₄ ø _{9+ δ}（0≤ X ≤0.3）样品通过溶胶-凝胶法结合了放电等离子烧结（SPS）制成。Y ³⁺替代Ca ^2+会同时增加塞贝克系数并降低导热系数。后者归因于晶格非谐性，结构变形和晶界面积的增加，从而增强了声子的散射。Ca _2.7 Y _0.3 Co ₄ O _{9+ δ}在1073 K处显示最大的无量纲品质因数（ZT = 0.194），因为它具有最大的塞贝克系数和最低的导热系数。该ZT值比未掺杂的Ca ₃ Co ₄ O ₉（在1073 K时为0.125）大55％。因此，Y ³⁺取代，溶胶-凝胶粉末合成和SPS对增强Ca ₃ Co ₄ O ₉的热电性能非常有效。