Ultrahigh Energy‐Storage Multilayer Ceramic Capacitors with Low Sintering Temperature

Multilayer ceramic capacitors (MLCCs) with ultrahigh power density are fundamental components in the modern electronics industry. However, the relatively low energy density or/and efficiency are still limited by high conduction losses and hysteresis loss. To address these issues, we propose a simple and efficient design in high-entropy 1/3BiFeO₃-1/3BaTiO₃-1/3Ca_0.5Sr_0.5TiO₃ ceramics (abbreviated as BFBCST) through three different sintering aids (CuO, MgO, MnO₂). With optimized sintering aids, the optimal sintering temperature is reduced by 150 to 975°C. Meanwhile, the synergistic strategy effectively minimizes hysteresis loss by lowering the domain switching barriers and decreases conduction losses by suppressing the volatilization of Bi³⁺ and minimizing valence variations of Fe³⁺ and Ti⁴⁺. Therefore, an ultrahigh energy storage density of 17.9 J cm^-3 with a high efficiency of 94.4% is simultaneously achieved under an electric field of 905 kV cm^-1 in BFBCST-based MLCCs with MnO₂ sintering aid. This approach should be universally applicable to designing high-performance dielectrics, which holds promise for extensive applications in MLCCs.