Ultrahigh energy density and efficiency BaTiO <sub>3</sub>-based multilayer ceramic capacitors
Biao He, Bin Zhou, Shiguang Yan, Fei Cao, Xuefeng Chen, Genshui Wang
Abstract
Multilayer ceramic capacitors (MLCCs) play a crucial role in pulsed power applications because of their rapid charge/discharge capabilities. However, the combination of high energy density and high efficiency is the main challenge in practical applications. This study presents barium titanate-based (BaTiO<sub>3</sub>-) lead-free relaxor ferroelectric (RFE) MLCCs formulated with 0.84BaTiO<sub>3</sub>–0.16Bi(Mg<sub>0.2</sub>Ni<sub>0.2</sub>Zn<sub>0.2</sub>Zr<sub>0.2</sub>Nb<sub>0.2</sub>)O<sub>3</sub> (0.84BT–0.16BMNZZN) and platinum inner electrodes via a tape-casting method. The introduction of the high-entropy component BMNZZN effectively enhances the relaxation behavior and local nanodomains while promoting grain refinement, resulting in a comprehensive improvement in insulation performance and energy storage performance. As a result, MLCCs exhibit excellent recoverable energy density (<i>W</i><sub>rec</sub> = 15.7 J∙cm<sup>−3</sup>) and ultrahigh efficiency (<i>η</i>) of 96.4% (@1614 kV∙cm<sup>−1</sup>), simultaneously showing good temperature stability over a range of −120‒100 °C (<i>W</i><sub>rec</sub> ≈ 8.9 J∙cm<sup>−3</sup> with a variation of less than ±4.85%, @1078 kV∙cm<sup>−1</sup>) and excellent fatigue resistance (<i>W</i><sub>rec</sub> ≈ 9.2 J∙cm<sup>−3</sup> with a variation of less than ±0.82% over 10<sup>7</sup> cycles, and <i>η</i> greater than 95%, @1078 kV∙cm<sup>−1</sup>). These findings indicate that BT–BMNZZN RFE MLCCs offer a viable solution for high-power energy storage capacitors.