Excellent Energy Storage Performances of Superparaelectric Relaxor BaTiO₃-Based Multilayer Capacitors by Low-Temperature Sintering

Multilayer ceramic capacitors (MLCCs) are critical components in modern electrical systems due to their ultrahigh power density and excellent temperature stability. However, their widespread adoption is hindered by low energy storage density (<i>U</i>_rec) and the high cost of noble-metal-based internal electrodes due to the high sintering temperature. Herein, we designed an eco-friendly and low-cost (0.97-<i>x</i>)BaTiO₃-0.03BiDyO₃-<i>x</i>Bi(Li_1/2Nb_1/2)O₃ (abbreviated as BT-0.03BD-<i>x</i>BLN at 0.04 ≤ <i>x</i> ≤ 0.08) system, which is sintered at a low sintering temperature and show a superparaelectric characteristic. Due to the low defect concentration resulting from the low sintering temperature of about 1030 °C and its superparaelectric relaxor state, the BT-0.03BD-0.06BLN MLCCs achieved an excellent <i>U</i>_rec = 10.12 J cm^-3 and η of ∼97% at the electric field of 1350 kV cm^-1. Moreover, the BT-0.03BD-0.06BLN MLCCs also exhibit an outstanding temperature at 20-160 °C and frequency at 1-125 Hz stabilities. In other words, this study not only provides a strategy for achieving high energy storage performances and reducing the cost of BaTiO₃-based MLCCs but also demonstrates the application potential of BT-0.03BD-0.06BLN MLCCs in next-generation high-power-density energy storage systems.