Relaxor ferroelectric ceramics have very high dielectric constant but relatively low electrical breakdown strength, while glass-ceramics exhibit higher electrical breakdown strength due to the more uniformly dispersed amorphous phases and submicrocrystals/nanocrystals inside. How to effectively combine the advantages of both relaxor ferroelectric ceramics and glass-ceramics is of 2 great significance for the development of new dielectric materials with high energy storage performances. In this work, we firstly prepared BaO-SrO-Bi2O3-Na2O-TiO2-Al2O3-SiO2 (represented by GS) glass powder, and then fabricated (Ba0.3Sr0.7)0.5(Bi0.5Na0.5)0.5TiO3+xwt.%GS ceramic composites (abbreviated as BS0. x=0,2,6,10,14,16,18). Submicrocrystals/nanocrystals with a similar composition to BS0.5BNT were crystalized from the glass, ensuring the formation of uniform core-shell structure in BS0.5BNT-xGS relaxor ferroelectric ceramic/glass-ceramic composites. When the addition amount of GS was 14 wt.%, the composite possessed both high dielectric constant (εr>3200 @1 kHz) and high electrical breakdown strength (Eb~170 kV/cm) at room temperature, and their recoverable energy storage density and efficiency were Wrec=2.1 J/cm 3 and η=65.2%, respectively. The BS0.5BNT-14GS composite also had several attractive properties such as good temperature, frequency, cycle stability, and fast charge-discharge speed. This work provides insights into the relaxor ceramic/glass-ceramic composites for pulsed power capacitors and sheds light on the utilization of the hybrid systems.

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Motivated by the detection of neutrons, europium‐doped Li2B4O7 glasses enriched with both lithium and boron elements with high cross‐section capture were developed. A highly effective method of realizing the self‐reduction of Eu3+ to Eu2+ ions in europium‐doped Li2B4O7 glasses prepared by high temperature melt‐quenching technology in air was revealed. The self‐reduction of Eu3+ to Eu2+ ions can be easily achieved by the partial replacement of B2O3 with BN within 2 mol% concentration. And the effect of partially replacing B2O3 with BN on the optical properties of europium‐doped Li2B4O7 glass are systematically studied by transmittance, photoluminescence, and radioluminescence spectra, together with the luminescence decay curves.