<p>The dielectrics in X8R-type ceramic capacitors need to be able to operate in a temperature range of − 55–150&#xa0;°C while maintaining capacitance variation Δ<i>C</i>/<i>C</i> ≤  ± 15%. Herein, 0.97BaTiO₃-0.03K_0.5Na_0.5NbO₃-MgO-<i>x</i>Yb₂O₃-Bi₄Ti₃O₁₂ (BT-3KNN-MgO-<i>x</i>Yb-B4TO) ceramics were prepared via a solid-state reaction method. The dielectric and resistive properties of these materials were examined. The dielectric spectra indicate that all Yb³⁺-doped ceramics exhibit a “core–shell” structure, with the sample containing 2.5&#xa0;mol% Yb³⁺ satisfying the X8R standards. At room temperature, the dielectric constant is approximately 1603, while the dielectric loss is 0.012. The incorporation of Yb³⁺ enhances the insulation properties of the BT-3KNN-MgO-<i>x</i>Yb-B4TO ceramics. The increase in resistivity is attributed to the fact that Yb³⁺ replaces the Ti⁴⁺, producing more oxygen vacancies and thereby inhibiting the electrons generated from oxygen loss during the sintering process. Furthermore, the influence of sintering temperature on the core–shell structure was investigated. As the sintering temperature increases, elements within the “shell” progressively diffuse into the “core”, resulting in an increased relative volume of the “shell”. This diffusion leads to a reduction in the dielectric peak of the shell, making the core–shell structure less pronounced. The findings presented herein provide a novel candidate for dielectrics for X8R-type ceramic capacitors.</p> Graphical abstract <p></p>