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Page 2 of 13 Xu et al. Microstructures 2023;3:2023034 https://dx.doi.org/10.20517/microstructures.2023.19

INTRODUCTION
NaNbO -based energy storage dielectric ceramics have excellent electrical properties, such as
3
antiferroelectric (AFE) properties, high polarization strength, and relative breakdown resistance. They are
lightweight and have a wide working temperature range, which is beneficial for practical applications and
[1,2]
has attracted the attention of many researchers . By using NaNbO as the base and adding a variety of
3
structural compounds to form solid solutions with different properties, energy storage dielectric ceramics
[3,4]
with excellent performance can be obtained . However, as an AFE material, NaNbO decreases the energy
3
storage efficiency owing to the large polarization hysteresis caused by the inevitable field-induced
AFE-relaxor ferroelectric (FE) phase transition while obtaining a high energy density .
[5,6]
Researchers often adjust the relaxation behavior of ceramics, reduce the average grain size, stabilize the AFE
type, and delay the AFE-FE transition by incorporating doping Bi-based composite perovskites to improve
the energy storage performance of NaNbO -based ceramics. For instance, NaNbO doped with
3
3
Bi(Ni Zr )O exhibits a breakdown field strength of 500 kV/cm, an energy storage density of 4.90 kV/cm ,
3
0.5
3
0.5
and an efficiency of 73% . An energy storage density of 3.70 J/cm and an energy storage efficiency of 77%
[7]
3
were obtained through doping with Bi(Mg Nb )O ceramics with a breakdown field strength of
2/3
3
1/3
460 kV/cm . Good results have been achieved, but the challenge of achieving low energy storage
[1]
efficiencies persists. Notably, there is still a lack of research on rare-earth-based composite perovskites.
Ye studied 0.96Na La NbO -0.04CaSnO , and a 2.1 /cm recoverable energy storage density (W ) and
[8]
3
rec
3
0.12
0.88
3
62% energy storage efficiency (η) were obtained. Although the energy storage performance was general,
doping with La inhibited P . The ceramics doped with La(Mg Zr )O in a Sr Bi TiO matrix studied by
3
0.7
0.5
0.5
r
3
0.2
[9]
Chen achieved an energy storage density of 1.22 J/cm and an ultrahigh energy storage efficiency of 98.2% .
3
[10]
The energy storage density was low, but η was high. Yang obtained a 6.5 J/cm W and 96% η by adding
3
rec
Sm and Ti to NaNbO . This shows that the energy storage efficiency of the matrix can be changed by
3+
4+
3
doping with rare-earth elements.
In studies of NaNbO , BaTiO , and Sr Bi TiO ceramics, doping with Bi (Mg Zr )O helped maintain
0.5
3
3
0.5
0.7
3
3
0.2
good performance stability [9,11,12] . Based on the above research, Sm(Mg Zr )O (SMZ) was introduced into a
3
0.5
0.5
NaNbO matrix, and (1−x)NaNbO Sm(Mg Zr )O (x = 0.05, 0.08, 0.12, and 0.15) (NN-SMZ) ceramics
3−x
0.5
3
0.5
3
were designed. The electrical properties, such as energy storage performance, temperature stability,
frequency stability, and resistance, were analyzed and studied. It is concluded that the energy storage
performance of the matrix can be improved by doping Sm ions at the A site of the perovskite structure,
3+
and the performance stability of the ceramics can be improved.
EXPERIMENTAL PROCEDURE
NN-SMZ was prepared using a conventional solid-state reaction. Na CO (99.8%), Nb O (99%), Sm O
5
2
2
3
2
3
(99.99%), ZrO (99%), and MgO (98.5%) were stoichiometrically weighed and ball-milled with Zr balls in
2
ethanol for 5 h. After drying, the mixed powders were calcined at 900 °C for 5 h and ball-milled again for
5 h. Polyvinyl alcohol (5%) was added as a binder to press the dried powder into a disk with a diameter of
8 mm and thickness of 1 mm. The disks were calcined at 550 °C for 4 h for glue extrusion. Finally, the
samples were embedded in a precursor powder of the same composition and sintered at 1,340 °C for 2 h.
The test instrument information during the experiment is added to the support material. The thicknesses
and silver electrode areas of the samples used for P-E testing are listed in Supplementary Table 1.