Dielectric ceramic capacitors are fundamental energy storage components in advanced electronics and electric power systems owing to their high power density and ultrafast charge and discharge rate. However, simultaneously achieving high energy storage density, high efficiency and excellent temperature stability has been a huge challenge for the practical capacitor applications of dielectric ceramics. These concerns have been addressed herein in relaxor ferroelectric grain core–shell structured 0.87BaTiO3–0.13Bi(Zn2/3(Nb0.85Ta0.15)1/3)O3@SiO2 multilayer ceramic capacitors (MLCCs) via our multiscale optimization strategy from atomic scale, to grain scale to device scale designs to increase the breakdown field strength and decrease the leakage current, which generates superior energy storage performance with a giant discharge energy density of 18.24 J cm−3, ultrahigh efficiency over 94.5%, and excellent temperature stability (<10%, 25 to 190 °C) and cycling stability. Compared with the 0.87BaTiO3–0.13Bi(Zn2/3(Nb0.85Ta0.15)1/3)O3 MLCC counterpart without SiO2 coating, the discharge energy density was enhanced by 80%. The multiscale optimization strategy should be a universal approach to improve the overall energy storage performance in dielectric ceramic multilayer capacitors.
