Abstract
Electrostatic energy-storage ceramic capacitors are essential components of modern electrified power systems. However, improving their energy-storage density while maintaining high efficiency to facilitate cutting-edge miniaturized and integrated applications remains an ongoing challenge. Herein, we report a record-high energy-storage density of 20.3 J cm-3 together with a high efficiency of 89.3% achieved by constructing a relaxor ferroelectric state with strongly enhanced local polarization fluctuations. This is realized by incorporating highly polarizable, heterovalent, and large-sized Zn and Nb ions into a Bi0.5Na0.5TiO3-BaTiO3 ferroelectric matrix with very strong tetragonal distortion. Element-specific local structure analysis revealed that the foreign ions strengthen the magnitude of the unit-cell polarization vectors while simultaneously reducing their orientation anisotropy and forming strong fluctuations in both magnitude and orientation within 1-3 nm polar clusters. This leads to a particularly high polarization variation (ΔP) of 72 μC cm-2, low hysteresis, and a high effective polarization coefficient at a high breakdown strength of 80 kV mm-1. This work has surpassed the current energy density limit of 20 J cm-3 in bulk Pb-free ceramics and has demonstrated that controlling the local structure via the chemical composition design can open up new possibilities for exploring relaxors with high energy-storage performance.
| Original language | English |
|---|---|
| Pages (from-to) | 13467-13476 |
| Number of pages | 10 |
| Journal | Journal of the American Chemical Society |
| Volume | 146 |
| Issue number | 19 |
| DOIs | |
| State | Published - May 15 2024 |
Funding
This work was supported by the Key Research and Development Program of Ministry of Science and Technology of China (No. 2022YFB3204000), and the National Natural Science Foundation of China (Nos. 22235002 and 22075014). A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. We thank Xianran Xing of the Institute of Solid State Chemistry, University of Science and Technology Beijing, for providing laboratory X-ray diffraction testing. Yuanpeng Zhang and Joerg C. Neuefeind acknowledge the support from UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the US Department of Energy.