Boosting energy storage performance with lead-free relaxor ferroelectric in BNT-based ceramics via introducing scheelite La2WTiO8

Driven by the information industry, there is an urgent need for lead-free ceramic materials exhibiting excellent recoverable energy storage density (W-rec) and energy storage efficiency (eta) to meet the practical application requirements of pulse power capacitors. Among these, Bi0.5Na0.5TiO3 (BNT) stands out as a highly promising and competitive environmentally-friendly ceramic material due to its exceptional dielectric properties. However, premature polarization saturation and low dielectric breakdown field (E-b) have been major obstacles to its practical application. Herein, the scheelite-structured La2WTiO8 (LWT) is successfully integrated with the perovskite-structured BNT to enhance the energy storage performance (ESPs) of BNT-based ceramics. The obtained results show that LWT doped into BNT matrix destroys the long-term ferroelectric order and effectively promotes the formation of polar nanoregions, which enhance E-b and delay polarization saturation. Ultimately, the optimized composition achieves the expected W-rec (similar to 6.3 J cm(-3)) and eta (similar to 78.9%) at 400 kV cm(-3) with excellent temperature stability (<9% variation in the temperature range of 20-200 degrees C) and frequency stability (similar to 2.8% variation in the frequency range of 1-100 Hz). In addition, a fast discharge performance of t(0.9) similar to 62.6 ns and a high power density of 105.71 MW cm(-3) at 200 kV cm(-1) are achieved. This work proposes a strategy to obtain high comprehensive ESPs of BNT-based ceramics, offering new prospects for the development of advanced pulse capacitors.