Ultrahigh-power-density BNT ferroelectric multilayer ceramic capacitors for pulse power energy conversion components

Ferroelectric (FE) materials are promising for applications in advanced high-power density systems/energy storage and conversion devices. However, the power density of ceramic components is limited by the electrode area and breakdown strength of bulk ceramic, while the multilayer structure is effective in enhancing the breakdown strength and realizing miniaturization. In this work, Bi_0.5Na_0.5TiO₃–BiAlO₃–NaNbO₃ multilayer ceramic capacitors (BNT–BA–NN MLCCs) were prepared as pulse power energy conversion components. The electrical properties of MLCCs with different layer thicknesses under temperature and pressure fields were investigated. The relaxor phase was observed in thin layer MLCCs, which was beneficial for pressure depolarization but led to a reduction in remnant polarization (P_r) and temperature stability. Therefore, MLCCs with an appropriate layer thickness are needed to satisfy energy conversion application. Results reveal that P_r is up to 39 μC cm⁻² and E_b increased to more than 26 kV mm⁻¹ in BNT–BA–NN MLCCs. On this basis, an ultrahigh output power density up to 2.2 × 10⁹ W kg⁻¹ (GW kg⁻¹) with an output voltage up to 9.8 kV mm⁻¹ is achieved in shock wave measurements, which is superior to that of the reported materials applied in high power pulse sources. The design of MLCCs provides an effective method to satisfy miniaturization and integration requirements for high-power applications.