Dielectric ceramics with relaxor characteristics are
promising
candidates to meet the demand for capacitors of next-generation pulse
devices. Herein, a lead-free Sb-modified (Sr0.515Ba0.47Gd0.01) (Nb1.9‑x
Ta0.1Sb
x
)O6 (SBGNT-based) tungsten bronze ceramic is designed and fabricated
for high-density energy storage capacitors. Using a B-site engineering
strategy to enhance the relaxor characteristics, Sb incorporation
could induce the structural distortion of the polar unit BO6 and order–disorder distribution of B-site cations as well
as the modulation of polarization in the SBGNT-based tungsten bronze
ceramic. More importantly, benefiting from the effective inhibition
of abnormal growth of non-equiaxed grains, Sb introduction into SBGNT-based
ceramics could effectively suppress the conductivity and leakage current
density, enhancing the breakdown strength, as proved by the electrical
impedance spectra. Consequently, a remarkable comprehensive performance
via balancing recoverable energy density (∼3.26 J/cm3) and efficiency (91.95%) is realized simultaneously at 380 kV/cm,
which surpasses that of the pristine sample without the Sb dopant
(2.75 J/cm3 and 80.5%, respectively). The corresponding
ceramics display superior stability in terms of fatigue (105 cycles), frequency (1∼200 Hz), and temperature (20∼140
°C). Further charge–discharge analysis indicates that
a high power density (89.57 MW/cm3) and an impressive current
density (1194.27 A/cm2) at 150 kV/cm are achieved simultaneously.
All of the results demonstrate that the tungsten bronze relaxors are
indeed gratifying lead-free candidate materials for dielectric energy
storage applications.
Developing high-performance dielectric capacitors is essential to meet the growing demands of hybrid electric vehicles and high-power applications. The energy storage efficiency and the temperature-variant energy storage properties should be...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.