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Concerning the practical applications, dielectric capacitors with simultaneously high recoverable energy density (W rec) and large energy storage efficiency (η) under a low electric field is imperative and challenging. Herein, a strategy of complex ions substitution is proposed to achieve the goal. The (1- x)(0.75Na 0.5 Bi 0.5 TiO 3 -0.25SrTiO 3)- x La(Mg 2/3 Ta 1/3)O 3 (NBST- x LMT) ceramics were fabricated through a solid-state reaction method. A significantly enhanced breakdown electric field (E b) of 246.03 kV/cm is obtained in NBST-0.06LMT ceramics due to the refined average grain size (AGS), the enhanced band gap width and the inhibited oxygen vacancies by LMT doping. Furthermore, a high W rec of 3.18 J/cm3and large η of 86% are concurrently achieved in NBST-0.06LMT ceramics under a relatively low electric field of 246 kV/cm. Meanwhile, the variations of (W rec , η) under 170 kV/cm are less than 10% from 30 ℃ to 200 ℃, indicating an excellent thermal stability. Besides, the ceramics show a fast discharge rate of 155 ns by a charge-discharge measuring. In general, our results demonstrate the strategy of complex ions substitution is an effective way to achieve high energy storage performance under a relatively low electric field in NBT-based ceramics. [Display omitted] • Complex ions (La3+, Mg2+ and Ta5+) substitution was proposed to achieve high energy storage performance. • An enhanced Eb (246.03 kV/cm) was realized in NBST ceramics. • A high Wrec of 3.18 J/cm3and large η of 86% were concurrently obtained under 246 kV/cm. • The (Wrec, η) exhibits excellent thermal stability from 30 ℃ to 200 ℃. [ABSTRACT FROM AUTHOR]

Abstract: Monodisperse CeO2 nanospheres with the average size of 40nm, self-assembled by well-crystalline CeO2 ultrafine nanoparticles were synthesized through a facile solvothermal route using n-butanol as solvent in the absence of any surfactant or template. The formation process of the monodisperse self-assembly CeO2 nanospheres is briefly discussed. The key function of n-butanol is investigated by comparative experiments. It is found that n-butanol not only serves as solvent, but also acts as surfactant in the formation of monodisperse self-assembly CeO2 nanospheres. Raman and XRD spectra show that the sample is pure cubic fluorite type of structure. Compared to the bulky CeO2 materials, the prepared CeO2 nanospheres exhibited an obvious blue-shifting in UV absorbance. The direct band gap energy of the obtained sample increases by exceeding 10%. Our study provides an effective approach to control CeO2 morphology which has potential application in synthesis of other nanomaterials. [Copyright &y& Elsevier]