Giant energy-storage density with ultrahigh efficiency in lead-free relaxors via high-entropy design

Next-generation advanced high/pulsed power capacitors rely heavily on dielectric ceramics with high energy storage performance. However, thus far, the huge challenge of realizing ultrahigh recoverable energy storage density (W-rec) accompanied by ultrahigh efficiency (eta) still existed and has become a key bottleneck restricting the development of dielectric materials in cutting-edge energy storage applications. Here, we propose a high-entropy strategy to design local polymorphic distortion including rhombohedral-orthorhombic-tetragonal-cubic multiphase nanoclusters and random oxygen octahedral tilt, resulting inultra small polar nanoregions, an enhanced breakdown electric field, and delayed polarization saturation. A giant W-rec similar to 10.06 J cm(-3) is realized in lead-free relaxor ferroelectrics, especially with an ultrahigh eta similar to 90.8%, showing breakthrough progress in the comprehensive energy storage performance for lead-free bulk ceramics. This work opens up an effective avenue to design dielectric materials with ultrahigh comprehensive energy storage performance to meet the demanding requirements of advanced energy storage applications.

Automated summary

This study proposes a high-entropy strategy to design local polymorphic distortion, resulting in ultra-small polar nanoregions, enhanced breakdown electric field, and delayed polarization saturation. A giant W-rec of around 10.06 J cm(-3) and an ultrahigh eta of around 90.8% are achieved in lead-free relaxor ferroelectrics, showing breakthrough progress in energy storage performance for lead-free bulk ceramics. This work opens up an effective avenue for designing dielectric materials with ultrahigh comprehensive energy storage performance.