Influence of Bi nonstoichiometry on the energy storage properties of 0.93KNN–0.07Bi_xMN relaxor ferroelectrics

Abstract

Ceramic-based dielectric capacitors are becoming more and more important in electronic devices. The ceramics of 0.93K[Formula: see text]Na[Formula: see text]NbO3–0.07Bix(Mg[Formula: see text]Nb[Formula: see text])O3 (0.93KNN–0.07BixMN) ([Formula: see text], 2/3, 0.75 and 0.95) were successfully fabricated by virtue of the solid reaction process in this work. The results showed that the amount of Bi content has a significant impact on the ceramics of 0.93KNN–0.07BixMN. XRD indicates that all specimens exhibit a pure perovskite structure and existing oxygen vacancy in the specimens. The mean grain size for all specimens belong to submicron scale, and the sample of [Formula: see text] owns the smallest grain size is 0.11[Formula: see text][Formula: see text]m. The maximum dielectric constant increases but the phase transition temperature [Formula: see text] exhibits a contrary tendency at 1[Formula: see text]MHz with increasing Bi concentration. Besides, all ceramics are relaxor ferroelectric. The impedance analysis further revealed that the activation energy of the ceramics increases with Bi content. Eventually, the highest [Formula: see text] of 58.8% and [Formula: see text] of 1.30[Formula: see text]J/cm3 are simultaneously achieved in the sample with [Formula: see text]. Overall, we demonstrate in this work that stoichiometry control of Bi in 0.93KNN–0.07BixMN ceramics is a practical method to obtain the desired structural, dielectric and energy storage properties.

Eu-doped K0.5Na0.5NbO3-(Ba,Sr)TiO3: A novel lead-free luminescent ferroelectric transparent ceramic with reversible photochromism

“…Environment-friendly lead-free KNN-based ceramics have been regarded as the most promising alternative to toxic lead-based piezoelectric materials, owing to their moderate dielectric constant, optimum piezoelectric response and good ferroelectricity. [8][9][10][11][12][13] Recently, RE-doped KNN ceramics have been verified to have both PC and PL modulation behaviors induced by vacancy-related defects (e.g., K/Na/O vacancies), [2][3][4][5][6][7] expanding the electrical applications to optoelectronic areas. Generally, pure KNN ceramics own poor relative density ($95%), low symmetry structure (orthorhombic phase) and large grain size (1-2 m).…”

Enthralling Storage Properties of (1–x)La0.03Na0.91NbO3–xBi(Li0.5Nb0.5)O3 Lead-Free Ceramics: High Energy Storage Applications

“…The calculated grain size standard deviation (σ) in this composition was found to be 0.015. A unique feature appeared in 0.88LNN–0.12BLN ceramics, as shown in Figure c, where a dense microstructure with a submicron grain size was noticed; reported work says it enhances the BDS of the ceramics system. ,, Earlier research confirmed that the BDS and the grain size of dielectric ceramics obey the following relationship , where E BDS is the BDS of dielectric ceramics and G is the grain size. Equation discloses that the BDS of the dielectric ceramics increases with grain size reduction, i.e., smaller grain size (submicron scale) results in higher BDS .…”

“…A unique feature appeared in 0.88LNN–0.12BLN ceramics, as shown in Figure c, where a dense microstructure with a submicron grain size was noticed; reported work says it enhances the BDS of the ceramics system. ,, Earlier research confirmed that the BDS and the grain size of dielectric ceramics obey the following relationship , where E BDS is the BDS of dielectric ceramics and G is the grain size. Equation discloses that the BDS of the dielectric ceramics increases with grain size reduction, i.e., smaller grain size (submicron scale) results in higher BDS . Our findings show that a little amount of BLN up to 0.12 mol impedes grain growth, above which, the trend is reversed because of the dominance effect of Bi 3+ and Li + ions at the A and B sites of the perovskite LNN (see Figure d), which affects the defect chemistry as well as host crystal structural properties.…”

Enhanced energy storage properties of Sr(Ti 0. 5 Zr 0 .5 ) O 3 modified (Na 0. 5 Bi 0 .5 ) Zhang1, Dai2, Pan3 et al. 2022Intl J of Energy Research13020View full textAdd to dashboardCite

“…The STZ additive remarkably influenced the P‐E loops shape, BDS , and polarization value of the BNT ceramics. Figure 6I displays a comparison of W rec and η for 0.80BNT‐0.20STZ ceramics and other lead‐free bulk ceramics 41‐54 . It is worth noting that the W rec and η of 0.80BNT‐0.20STZ ceramic are superior to those of most BNT‐based bulk ceramics, which have great application potential in pulse power equipment.…”

“…Figure 6I displays a comparison of W rec and η for 0.80BNT-0.20STZ ceramics and other lead-free bulk ceramics. [41][42][43][44][45][46][47][48][49][50][51][52][53][54] It is worth noting that the W rec and η of 0.80BNT-0.20STZ ceramic are superior to those of most BNT-based bulk ceramics, which have great application potential in pulse power equipment.…”