ВПЛИВ СИНТЕЗУ НА ДІЕЛЕКТРИЧНІ ВЛАСТИВОСТІ La0,5Li0,5-xNaxTiO3
Using X-ray powder, diffraction the sequence of reactions occurring during the synthesis La0.5Li0.5-xNaxTiO3 by solid-state reaction technique has been determined. Using electron microscopy it has been shown that the grain size decreases with increasing x in La0.5Li0.5-xNaxTiO3 system. The influence...
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| Дата: | 2021 |
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| Автори: | , , , , |
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| Мова: | Англійська |
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V.I.Vernadsky Institute of General and Inorganic Chemistry
2021
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Репозитарії
Ukrainian Chemistry Journal| _version_ | 1871465710494941184 |
|---|---|
| author | Plutenko, Tetiana V'yunov, Oleg Fedorchuk, Oleksandr Yanchevskii, Oleg Belous, Anatolii |
| author_facet | Plutenko, Tetiana V'yunov, Oleg Fedorchuk, Oleksandr Yanchevskii, Oleg Belous, Anatolii |
| author_institution_txt_mv | [
{
"author": "Tetiana Plutenko",
"institution": "V.I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Sciences of Ukraine"
},
{
"author": "Oleg V'yunov",
"institution": "V. I. Vernadsky Institute of General and Inorganic Chemistry"
},
{
"author": "Oleksandr Fedorchuk",
"institution": "V.I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Sciences of Ukraine"
},
{
"author": "Oleg Yanchevskii",
"institution": "V.I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Sciences of Ukraine"
},
{
"author": "Anatolii Belous",
"institution": "V.I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Sciences of Ukraine"
}
] |
| author_sort | Plutenko, Tetiana |
| baseUrl_str | https://ucj.org.ua/index.php/journal/oai |
| collection | OJS |
| datestamp_date | 2026-07-22T08:23:46Z |
| description | Using X-ray powder, diffraction the sequence of reactions occurring during the synthesis La0.5Li0.5-xNaxTiO3 by solid-state reaction technique has been determined. Using electron microscopy it has been shown that the grain size decreases with increasing x in La0.5Li0.5-xNaxTiO3 system. The influence of the grain size of ceramics on the dielectric characteristics has been indicated. The frequency dependences of permittivity and dielectric loss tangent have been investigated by ac impedance spectroscopy. It has been established that ceramic sample of La0.5Li0.4Na0.1TiO3 solid solution has the largest value of permittivity ɛ > 104 at wide frequency range (1–104 Hz) in La0.5Li0.5-xNaxTiO3 system. |
| doi_str_mv | 10.33609/2708-129X.87.05.2021.15-24 |
| first_indexed | 2025-09-24T17:43:39Z |
| format | Article |
| fulltext |
15
UDC: 549.641.1; 661.8; 621.315.61; 621.317 doi: 10.33609/2708-129X.87.05.2021.15-24
THE SYNTHESIS IMPACT ON DIELECTRIC PROPERTIES
OF La0.5Li0.5-xNaxTiO3
T.O. Plutenko, O.I. V’yunov *, O.P. Fedorchuk, O.Z. Yanchevskii, A.G. Belous
V.I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Sciences of
Ukraine, Akad. Palladin ave, 32/34, Kyiv, 03142, Ukraine
e-mail: vyunov@ionc.kiev.ua
Using X-ray powder, diffraction the sequence of reactions occurring during the synthesis
La0.5Li0.5-xNaxTiO3 by solid-state reaction technique has been determined. Using electron mi-
croscopy it has been shown that the grain size decreases with increasing x in La0.5Li0.5-xNax-
TiO3 system. The influence of the grain size of ceramics on the dielectric characteristics has
been indicated. The frequency dependences of permittivity and dielectric loss tangent have
been investigated by ac impedance spectroscopy. It has been established that ceramic sample
of La0.5Li0.4Na0.1TiO3 solid solution has the largest value of permittivity ɛ > 104 at wide frequen-
cy range (1–104 Hz) in La0.5Li0.5-xNaxTiO3 system.
Keywords: solid solution, lithium-sodium-lanthanum titanate, perovskite, complex im-
pedance, colossal permittivity.
INTRODUCTION. LLTO and other ABO3
perovskites attract great attention for the last
years and are investigated intensively. These
materials can be used in microelectronics and
electrochemical devices. One of the conductive
perovskites applications is the development of
electrolytes for lithium-ion batteries, which are
for now the critical technology in energy storage.
Such solid electrolytes have crucial advantages
over liquid analogs: nonflammability and
generally improved safety (critical for power
supplies of vehicles), low-temperature stability,
higher power, and energy densities [1, 2].
There are other different classes of materials
for solid electrolytes: phosphates on the base
of NASICON, LISICON, garnets [3– 5].
But LLTO stands out due to relatively high
conductivity σ = 10-3 S/cm for bulk samples [6].
It is the ion-conducting material, in which the
high ionic conductivity provided by lithium
transport through vacancies in A-sublattice,
formed by lanthanum and substituting ions and
surrounded by oxygen ions, in the perovskite
structure.
Perovskite-based materials also demon-
strate the giant dielectric constant [7]. High
dielectric constant (ε′ = 103–106) is the key fea-
ture for further miniaturization of microelect
ronics components, development of capaci-
tors for high-energy storage (Multi-Layer Ce-
ramic Capacitors [8]). LLTO-based materials
are also remarkable among other perovskites
FORMATION DURING THE SYNTHESIS AND DIELECTRIC PROPERTIES OF La0.5Li0.5-xNaxTiO3
16 ISSN 2708-129X. Укр. хім. журн., 2021
PHYSICAL CHEMISTRY
due to the stability of properties in a wide
temperature range [7]. One of such materials
is, for example, La0.67Li0.25Ti0.75Al0.25O3 ceram-
ics. It was revealed, that high dielectric per-
mittivity in the case of La0.67Li0.25Ti0.75Al0.25O3
is associated with the barrier layer capacitor
effect, caused by the depletion of Li ions at
the grain boundaries. Therefore, conductiv-
ity, structural and morphological features of
LLTO have a considerable impact on the giant
dielectric constant in it.
It was found that in the La0.5Na0.5TiO3
(LNTO) material high dielectric constant is due
to the heterogeneous distribution of cations,
which leads to a strong local field fraction [9]. It
was also shown that solid solutions are formed
in the system La0.5Li0.5-xNaxTiO3 (LLNTO) [10].
The dielectric properties of LLNTO have been
studied in the microwave region. It can be as-
sumed that in the frequency range of 100–106 Hz
the presence of sodium will lead to a strong
change in the dielectric properties. At first sight,
sodium has a big ionic radius and causes many
effects, leading to reduction in both conductiv-
ity and dielectric constant [10]. It decreases the
concentration of mobile charge carriers; reduces
the number of vacancies in A site. But also so-
dium provokes shifts in the crystal structure of
perovskite and has an ambiguous impact on re-
sulting properties [11–13].
Despite the long-lasting studies, there are
many open challenges regarding lithium con-
ductive perovskites. It is known, for example,
that synthesis of these ones is a complex and
hard task. Almost all of the existing works
concentrated on the final properties of ob-
tained materials without the understanding of
intermediate processes during the synthesis.
In this paper, we studied the formation and
changes of transitional phases during the La0.
5Li0.5-xNaxTiO3 ceramics synthesis by solid-state
reactions technique in a temperature range
20–1300 oC as an attempt to clarify the nature
of these processes. In addition, we studied the
effect of increasing sodium concentration on
dielectric properties of La0.5Li0.5-xNaxTiO3.
EXPERIMENT AND DISCUSSION OF THE
RESULTS. Samples were obtained from stoi-
chiometric amounts of dried Li2CO3 (Merck),
Na2CO3 (Merck), La2O3 (Aldrich 99.99%), and
TiO2 (Aldrich 99 %) by solid-state reaction
technique. Li2CO3 and Na2CO3 compounds
were dried at 300 ºC, La2O3 at 800 ºC, and TiO2
at 600 ºC. The mixtures of Li2CO3, Na2CO3,
La2O3, and TiO2 were ground in an agate mor-
tar with acetone, and calcined in air for 4 h at
1250 ºC. The rate of temperature increase was
200 ºC/hour. The phases were characterized by
X-ray powder diffractometry (XRPD) using
DRON-4-07 diffractometer (Cu Kα radiation;
40 kV, 20 mA). The calcined powders were
ground and pressed into pellets with a diame
ter of 10 mm and a thickness of 6 mm under
a pressure of 500 kg/cm2 (50MPa). The pellets
were sintered at 1300–1330 ºC depending on
Na content (6 h). Finally, samples with 1 mm
thickness were cut out from prepared raw ce-
ramic.
In order to determine intermediate phases
during synthesis, isothermal heat treatment was
carried out in the temperature range from room
temperature (RT) to 1300 °C during 2 h. The
change in the phase composition was studied in
the temperature range 20–1100 ºC by method
X-ray phase diffraction (XRD) analysis using
DRON-4-07 CuKα-radiation; 40 kV, 20 mA).
SiO2 and Al2O3 were used as external standards
(for 2Θ and intensity).
Grain sizes of ceramic samples of
La0.5Li0.5-xNaxTiO3 system (where 0 ≤ x ≤ 0.5)
T.O. Plutenko, O.I. V’yunov, O.P. Fedorchuk, O.Z. Yanchevskii, A.G. Belous
17https://ucj.org.ua
UCJ № 5 / Vol. 87
were determined using a scanning electron
microscope JEM 10CX II (JEOL) and scan-
ning electron microscope SEC miniSEM
SNE 4500MB equipped with EDAX Element
PV6500/00 F spectrometer. Sintered cylindri-
cal pellets 10 mm in diameter and 2 mm thick,
with evaporated electrodes, were used for elec-
trical measurements.
Impedance spectroscopy measurements we
re performed using a 1260 Impedance / Gain
phase Analyzer (Solartron Analytical).
Using X-ray powder diffraction analy-
sis it has been shown that single-phase sol-
id solutions in La0.5Li0.5-xNaxTiO3 system are
formed at temperatures above 1200 °C (Fig. 1).
All samples of La0.5Li0.5-xNaxTiO3 system have
rhombohedral (trigonal) symmetry with space
group R-3c. The parameters of the unit cell
were calculated by the full-profile Rietveld anal-
ysis. As can be seen from Fig. 2, the parame
ters of the unit cell in the La0.5Li0.5-xNaxTiO3
system change by Vegard's law, which indicates
the formation of solid solutions. The increase
in the volume of the unit cell with increasing
x is explained by the rise in the average ionic
radius in the lithium-sodium sublattice.
Intermediate phases of synthesis depending
on the temperature of calcination are presen
ted in Table 1.
Fig. 1. X-ray powder diffraction analysis of
La0.5Li0.5-xNaxTiO3 at x = 0.2, calcined at different
temperatures. Marked phases La0.5Li0.3Na0.2TiO3 (◊),
La0.5Na0.5TiO3 (□), La2O2CO3 (●), TiO2 (○), Na2Ti3O7
(▼), Li2Ti2O5 (▲), Na2Ti2O5 (*), La2O3 (♦), La2Ti2O7
(■).
Fig. 2. Dependence of the unit cell parameters a, c (a) and unit cell volume V (b) of La0.5Li0.5-xNaxTiO3
on x.
FORMATION DURING THE SYNTHESIS AND DIELECTRIC PROPERTIES OF La0.5Li0.5-xNaxTiO3
18 ISSN 2708-129X. Укр. хім. журн., 2021
PHYSICAL CHEMISTRY
Table 1
Phase composition of powders in the La0.5Li0.5-xNaxTiO3 system
T, °C х = 0 х = 0.2 х = 0.5
20–400 Li2CO3, TiO2, La(OH)3 Na2CO3, Li2CO3, TiO2, La(OH)3 TiO2, Na2CO3, La(OH)3
500 TiO2, Li2TiO3, La2O2CO3 TiO2, Li2TiO3, Na2CO3, La2O2CO3 TiO2, Na2CO3, La2O2CO3
600 TiO2, Li2TiO3, La2O3 TiO2, Li2TiO3, Na2CO3, La2O2CO3 TiO2, Na2CO3, La2O2CO3
800 TiO2, Li2Ti2O5, La2Ti2O7 TiO2, La2O2CO3, La2O3, Li2Ti2O5,
Na2Ti2O5, Na2Ti3O7
TiO2, La2O2CO3, La2O3,
Na2Ti2O5, Na2Ti3O7, Na2TiO3
900 TiO2, La2O3,
La0.5Li0.5TiO3, Li2Ti2O5,
Li2Ti3O7, La2Ti2O7
TiO2, La2O3, La2Ti2O7,
La0.5Li0.5TiO3, Li2Ti2O5, Li2Ti3O7,
Na2Ti2O5, Li4Ti5O12
TiO2, La2O3, Na2Ti2O5,
Na2Ti3O7, Na2TiO3
1000 TiO2, La2O3,
La0.5Li0.5TiO3, Li2Ti2O5,
Li2Ti3O7, La2Ti2O7
TiO2, La2O3, La2Ti2O7,
La0.5Li0.5TiO3, Li2Ti2O5, Li2Ti3O7,
Na2Ti2O5, Na2TiO3, NaLiTi3O7,
Li4Ti5O12
TiO2, La2O3, La2Ti2O7,
Na2Ti2O5, Na2Ti3O7, Na2TiO3,
Na4Ti5O12
1100 Li2Ti2O5, La0.5Li0.5TiO3,
La2Ti2O7
Li2Ti2O5, Na2Ti2O5, La0.5Li0.5TiO3,
La0.5Na0.5TiO3, La2Ti2O7
Na2Ti2O5, La2Ti2O7,
La0.5Na0.5TiO3
1200 La0.5Li0.5TiO3 La0.5Li0.3Na0.2TiO3, La0.5Li0.5TiO3,
La0.5Na0.5TiO3
La0.5Na0.5TiO3
1300 La0.5Li0.5TiO3 La0.5Li0.3Na0.2TiO3 La0.5Na0.5TiO3
Fig. 3. Scheme of the La0.5Li0.5-xNaxTiO3 solid solutions synthesis by the solid-state reaction technique.
T.O. Plutenko, O.I. V’yunov, O.P. Fedorchuk, O.Z. Yanchevskii, A.G. Belous
19https://ucj.org.ua
UCJ № 5 / Vol. 87
The scheme of phase transformation occur-
ring during La0.5Li0.5-xNaxTiO3 synthesis by the
solid-state reaction technique is presented in
Fig. 3.
Synthesis by the solid-state reaction tech-
nique is a complex and multi-stage process.
At room temperature in contact with air La2O3
absorbs water and forms lanthanum hydroxide
La(OH)3:
La2O3 + 3H2O 20–400 °C 2La(OH)3
At higher temperatures, lanthanum hydro
xide intensively adsorbs carbon dioxide pro-
ducing lanthanum dioxycarbonate.
2La(OH)3 + CO2
500–800 °C
La2O2CO3 + 3H2O
Titanium (IV) oxide react with lithium car-
bonate to produce lithium metatitanate and
carbon dioxide:
Li2CO3 + TiO2
500–600 °C
Li2TiO3 + CO2↑
In the temperature range from 700 to
800 °C a reaction between lithium metatitanate
and titanium (IV) oxide and the formation of
Li2Ti2O5 takes place.
Li2TiO3 + TiO2
700–800 °C
Li2Ti2O5
Na2CO3 + 2TiO2
700–800 °C Na2Ti2O5 + CO2↑
Decomposition of lanthanum dioxycar-
bonate leads to La2O3 formation:
La2O2CO3
800–900 °C La2O3+ CO2↑
Complicated parallel processes of Na2Ti3O7
formation can be presented by:
Na2Ti2O5 + TiO2
800–1000 °C Na2Ti3O7
Formation of La2Ti2O7 occurs during the re-
action between lanthanum hydroxide and tita-
nium (IV) oxide:
La2O3 + 2TiO2
850–1000 °C La2Ti2O7
Li2Ti2O5 phase reacts with La2Ti2O7 to form
La0.5Li0.5TiO3
Li2Ti2O5 + La2Ti2O7
900–1100 °C
4La0.5Li0.5TiO3
At the same time parallel processes of
Li2Ti3O7 formation/decomposition occur:
Li2Ti2O5 + TiO2
900–1000 °C
Li2Ti3O7
Na2Ti2O5 + La2Ti2O7
800–1100 °C 4La0.5Na0.5TiO3
After all, solid solution La0.5Li0.5-xNaxTiO3
is formed by the interaction of two perovskite
phases of La0.5Na0.5TiO3 and La0.5Li0.5TiO3:
xLa0.5Na0.5TiO3 + (1-x)La0.5Li0.5TiO3
1200–1250 °C
1200–1250 °C La0.5Li0.5-xNaxTiO3
Fig. 4 shows SEM photographs of
La0.5Li0.5-xNaxTiO3 samples. The grain size of
ceramics in La0.5Li0.5-xNaxTiO3 solid solutions
decreases from 4.5 to 3.5 μm for x = 0.15 and
0.35, respectively. Sintering reduces surface
area by growing bonds between contacting
particles during heating. Due to random ori-
entations of the particles, the bond forms with
an embedded grain boundary accommodating
the crystal disorientation between particles.
Effectively, early sinter bonding replaces sur-
face area with a lower energy of grain bound-
ary area. As surface area is annihilated, the
driving force of the process declines, resulting
in slower sintering rates. Mass transport mech-
anisms act a great role during sintering. From
one point of view, the sintering temperature of
La0.5Li0.5-xNaxTiO3 rises with x and this must
lead to an increase in grain size of ceramics.
On the other hand, the solid solution contains
elements Li and Na that tend to evaporate at
high temperatures, resulting in the forma-
tion of vacancies. Evaporation from the grain
FORMATION DURING THE SYNTHESIS AND DIELECTRIC PROPERTIES OF La0.5Li0.5-xNaxTiO3
20 ISSN 2708-129X. Укр. хім. журн., 2021
PHYSICAL CHEMISTRY
boundary leads to a decrease in the mass trans-
fer of the substance, which in turn leads to the
appearance of smaller grains [14, 15]. The im-
portance of small grain size is illustrated in
terms of the increased dielectric constant of
barium titanate and reduced sensitivity of it to
temperature [16].
Fig. 4. Micrographs of La0.5Li0.5-xNaxTiO3 at x = 0.15 (a), 0.25 (b), 0.35 (c).
Fig. 5. a - Frequency dependence of dielectric constant La0.5Li0.5-xNaxTiO3 solid solutions at x = 0(1),
0.1(2), 0.2(3), 0.3(4); inset: the dependence of the dielectric constant on x at a frequency of 1 Hz. b - Fre-
quency dependence of dielectric loss tangent in La0.5Li0.5-xNaxTiO3 at x = 0(1), 0.1(2), 0.2(3), 0.3(4).
Fig. 5 shows the frequency dependencies of
the dielectric constant (Fig. 5a) and dielectric
loss tangent (Fig. 5b) at room temperature. So
lid solutions La0.5Li0.5xNaxTiO3 with a sodium
concentration less than x < 0.25 exhibit high
dielectric constant ɛ > 103 at low frequencies
(f ≤ 10 Hz). At x = 0.3 the dielectric constant
gradually decreases, which may be associated
with a decrease in the grain size (Fig. 4) and
an increase in the total number of grains in the
ceramic sample. The mobility of lithium in the
grain core is greater than at the grain boun
dary [16]. As the grain size decreases, the pro-
portion of grain boundaries increases, which re-
duces the contribution to polarization, and the
dielectric constant decreases. The dielectric loss
tangent (which is determined by the dissipation
of energy due to the movement of charges) de-
creases with an increase in the sodium concen-
tration at frequencies f > 103 Hz (Fig. 5b). As can
be seen from Fig. 5a, the value of the dielectric
constant in the La0.5Li0.5-xNaxTiO3 system passes
through a maximum in the La0.5Li0.4Na0.1TiO3
solid solution. It is known that in solid solutions
where lithium is gradually replaced by sodium
in the lanthanum sublattice, the mobility of
T.O. Plutenko, O.I. V’yunov, O.P. Fedorchuk, O.Z. Yanchevskii, A.G. Belous
21https://ucj.org.ua
UCJ № 5 / Vol. 87
lithium decreases. On the other hand, an in-
crease in the amount of sodium increases the
unit cell volume, which expands the distance
by which the charge carrier can move (Fig. 2).
Described above factors lead to contradictory
effects that explain the maximum conductivity
in the La0.5Li0.4Na0.1TiO3 solid solution. As at x
= 0.1 concentration, the number of vacancies
and charge carriers Li+ is still quite large and
there is no Li-ion conduction, which leads to
high dielectric response.
CONCLUSIONS. The structure of
La0.5Li0.5-xNaxTiO3 perovskites, with 0 < x < 0.5,
has been deduced with the Rietveld method. It
has been found that an increase in x leads to the
rise in unit cell volume that can be explained by
the rise in the average ionic radius in the lantha-
num sublattice. Using X-ray powder diffraction
analysis, it has been found that at the first stage
two phases of La0.5Li0.5TiO3 and La0.5Na0.5TiO3
are formed while synthesis of La0.5Li0.5-xNaxTiO3.
The final solid solution is formed by the in-
teraction between lithium-lanthanum titanate
and sodium-lanthanum titanate. Intermediate
main phases during solid-state reaction synthe-
sis are La2O2CO3, Li2TiO3, Na2Ti2O5, Na2Ti3O7,
Li2Ti3O7. Using SEM it has been shown that
grain size of ceramics in La0.5Li0.5-xNaxTiO3 so
lid solutions decreases from 4.5 to 3.5 μm for
x = 0.15 and 0.35, respectively. Impedance
spectroscopy has been used to analyze dielectric
permittivity and as a result lithium mobility in
La0.5Li0.5-xNaxTiO3 system. The dielectric constant
passes through a maximum in La0.5Li0.4Na0.1TiO3
ceramic. This can be explained by the increase
in lithium ions mobility due to the growth of
unit cell volume which makes a contribution to
the polarization and leads to the maximum va
lue of dielectric constant in these materials.
Acknowledgments. The work was sup-
ported by the Research program of the
Ukrainian National Academy of Scien
ces “New functional substances and ma-
terials for chemical production” (Fine
Chemicals), project № 0119U101351.
ВПЛИВ СИНТЕЗУ НА ДІЕЛЕКТРИЧНІ
ВЛАСТИВОСТІ La0,5Li0,5-xNaxTiO3
Т. О. Плутенко, О. І. В’юнов *, О. П. Фе-
дорчук, О. З. Янчевський, А. Г. Білоус
Інститут загальної та неорганічної хімії
ім. В. І. Вернадського НАН України, просп.
Акад. Палладіна 32/34, Київ 03142, Україна
* e-mail: vyunov@ionc.kiev.ua
Тверді розчини на основі титанату лі-
тію-натрію-лантану La0,5Li0,5-xNaxTiO3 син-
тезовано методом твердофазних реакцій за
температур понад 1200 °C. За допомогою ме-
тоду рентгенівської порошкової дифракції
визначено послідовність реакцій, що відбу-
ваються під час синтезу. Встановлено, що на
першому етапі синтезу La0,5Li0,5-xNaxTiO3 іде
одночасне утворення двох перовськитних
фаз La0,5Li0,5TiO3 та La0,5Na0,5TiO3. Кінцевий
твердий розчин утворюється при взаємо-
дії між титанатом літію-лантану та титана-
том натрію-лантану. Основними проміж-
ними фазами є La2O2CO3, Li2TiO3, Na2Ti2O5,
Na2Ti3O7, Li2Ti3O7. За допомогою методу
Рітвельда було визначено параметри криста-
лічної структури La0,5Li0,5-xNaxTiO3. Усі зраз-
ки системи La0,5Li0,5xNaxTiO3 мають ромбое-
дричну (тригональну) симетрію з просторо-
вою групою R-3c. Параметри елементарної
FORMATION DURING THE SYNTHESIS AND DIELECTRIC PROPERTIES OF La0.5Li0.5-xNaxTiO3
22 ISSN 2708-129X. Укр. хім. журн., 2021
PHYSICAL CHEMISTRY
комірки в системі титанатів літію-натрі-
ю-лантану змінюються відповідно до закону
Вегарда, що свідчить про утворення твердих
розчинів. Знайдено, що збільшення x при-
зводить до збільшення об’єму елементарної
комірки, що можна пояснити зростанням
середнього іонного радіуса в підґратці лан-
тану. За допомогою електронної мікроско-
пії показано, що розмір зерен зменшується
зі збільшенням x у системі La0,5Li0,5xNaxTiO3.
Механізми масового транспорту відіграють
велику роль під час спікання. З одного боку,
температура спікання La0,5Li0,5-xNaxTiO3 під-
вищується з x, і це повинно призвести до
збільшення розміру зерен кераміки. З іншо-
го боку, твердий розчин містить іони літію
і натрію, які мають тенденцію до випаро-
вування за високих температур, що при-
зводить до утворення вакансій. Утворення
вакансій на границях зерен призводить до
зменшення масообміну речовини, що, сво-
єю чергою, призводить до появи менших
за розміром зерен. Показано вплив розмі-
ру зерен кераміки на діелектричні характе-
ристики. За допомогою методу імпедансної
спектроскопії було вивчено діелектричні
властивості в системі La0,5Li0,5-xNaxTiO3. По-
казано, що значення діелектричної проник-
ності проходить через максимум у кераміці
La0.5Li0.4Na0.1TiO3. Це можна пояснити вели-
кою кількістю іонів літію та збільшенням їх-
ньої рухливості внаслідок збільшення об’є-
му елементарної комірки, що дає великий
вклад у поляризацію і призводить до макси-
мального значення діелектричної проник-
ності в цих матеріалах.
Ключові слова: твердий розчин, тита-
нат літію-натрію-лантану, перовськит, ме-
тод комплексного імпедансу, гігантська ді
електрична проникність.
ЛІТЕРАТУРА
1. Yu K., Tian Y., Gu R., Jin L., Ma R., Sun H.,
Xu Y., Xu Z., Wei X. Ionic conduction,
colossal permittivity and dielectric relaxation
behavior of solid electrolyte Li3xLa2/3−xTiO3
ceramics. Journal of the European Ceramic
Society. 2018, 38(13). P. 4483–4487.
https://doi.org/10.1016/j.jeurceramsoc.
2018.05.023.
2. Song F., Yamamoto T., Yabutsuka T., Yao T.,
Takai Sh. Synthesis and Characterization
of LAGP-Based Lithium Ion-Conductive
Composites with an LLTO Additive. Journal
of Alloys and Compounds. 2021, 853. 157089.
https://doi.org/10.1016/j.jallcom.2020.157089.
3. Thangadurai V., Narayanan S., Pinzaru D.
Garnet-type solid-state fast Li ion conductors
for Li batteries: critical review. Chemical
Society Reviews. 2014, 43. Р. 4714–4727.
https://doi.org/10.1039/C4CS00020J.
4. Zhang H., Hao S., Lin J. Influence of Li2O-
B2O3 glass on ionic migration and interfacial
properties of La2/3−xLi3xTiO3 solid electrolyte.
Journal of Alloys and Compounds. 2017, 704.
Р. 109–116.
https://doi.org/10.1016/j.jallcom.2017.02.059.
5. Adachi G., Imanaka N., Aono H. Fast Li+
Conducting Ceramic Electrolytes. Advanced
Materials. 1996, 8. Р. 127–135.
https://doi.org/10.1002/adma.19960080205.
6. Inaguma Y., Liquan C., Itoh M., Nakamura T.,
Uchida T., Ikuta H., Wakihara M. High ionic
conductivity in lithium lanthanum titanate.
Solid State Communications. 1993, 86(10).
Р. 689–693.
https://doi.org/10.1016/0038-1098(93)90841-A.
7. García-Martín S., Morata-Orrantia A., Agu
irre M. H., Alario-Franco M. Á. Giant barrier
layer capacitance effects in the lithium ion
conducting material La0.67Li0.25Ti0.75Al0.25O3.
Applied Physics Letters. 2005, 86. 043110.
http://dx.doi.org/10.1063/1.1852717.
T.O. Plutenko, O.I. V’yunov, O.P. Fedorchuk, O.Z. Yanchevskii, A.G. Belous
23https://ucj.org.ua
UCJ № 5 / Vol. 87
8. Peng Zh., Wang J., Liang P., Zhu J., Zhou X.,
Chao X., Yang Z. A new perovskite-related
ceramic with colossal permittivity and
low dielectric loss. Journal of the European
Ceramic Society. 2020, 40(12). Р. 4010–4015.
https://doi.org/10.1016/j.jeurceramsoc.2020.
04.030.
9. Nakamura T., Sun P.-H., Shan Y. J., Inaguma Y.,
Itoh M., Kim I.-S. On the perovskite-related
materials of high dielectric permittivity with
small temperature dependence and low
dielectric loss. Ferroelectrics. 1997, 196(1).
Р. 205–209.
https://doi.org/10.1080/00150199708224163.
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on lithium containing titanates. Journal of
the European Ceramic Society. 2003, 23(14).
Р. 2525–2528.
https://doi.org/10.1016/S0955-2219(03)
00185-7.
11. Sanz J., Rivera A., León C., Santamaría J.,
Várez A., V’yunov O., Belous A. G. Li mobility
in (Li,Na)yLa0.66-y/3TiO3 perovskites (0.09<y≤
≤0.5). A model system for the percolation
theory. Materials Research Society. 2003, 756.
Р. 231–236.
https://doi.org/10.1557/PROC-756-EE2.3.
12. Sanjuan M. L., Laguna M. A., Belous A. G.,
V’yunov O. I. On the local structure and
lithium dynamics of La0.5(Li,Na)0.5TiO3 ionic
conductors. A Raman study. Chem. Mater.
2005, 17. Р. 5862–5866.
https://doi.org/10.1021/cm0517770.
13. Herrero C. P., Varez A., Rivera A., Santa
marıa J., Leon C., V’yunov O., Belous A. G.,
Sanz J. Influence of vacancy ordering on the
percolative behavior of (Li1-xNax)3yLa2/3-yTiO3
perovskites. J. Phys. Chem. B. 2005, 109.
Р. 3262–3268.
https://doi.org/10.1021/jp046076p.
14. Kambale K., Mahajan A., Butee S.P. Effect
of grain size on the properties of ceramics.
Metal Powder Report. 2019, 74(3). Р. 689–693.
http://dx.doi.org/10.1016/j.mprp.2019.04.060.
15. German R. M. Sintering trajectories: de
scription on how density, surface area, and
grain size change. The Minerals, Metals
& Materials Society. 2016, 68. Р. 878–884.
https://doi.org/10.1007/s11837-015-1795-8.
16. Subbarao E.C. Grain size effects in
advanced ceramics. Colloids and Surfaces
A: Physicochemical and Engineering Aspects.
1998, 133(1–2). Р. 3–11.
https://doi.org/10.1016/S0927-7757(97)
00104-0.
REFERENCES
1. Yu K., Tian Y., Gu R., Jin L., Ma R., Sun H.,
Xu Y., Xu Z., Wei X. Ionic conduction,
colossal permittivity and dielectric relaxation
behavior of solid electrolyte Li3xLa2/3−xTiO3
ceramics. Journal of the European Ceramic
Society. 2018. 38 (13): 4483–4487. https://doi.
org/10.1016/j.jeurceramsoc.2018.05.023.
2. Song F., Yamamoto T., Yabutsuka T., Yao T.,
Takai S. Synthesis and Characterization
of LAGP-Based Lithium Ion-Conductive
Composites with an LLTO Additive. Journal
of Alloys and Compounds. 2021. 853: 157089.
https://doi.org/10.1016/j.jallcom.2020.
157089.
3. Thangadurai V., Narayanan S., Pinzaru D.
Garnet-type solid-state fast Li ion conductors
for Li batteries: critical review. Chemical
Society Reviews. 2014. 43: 4714–4727. https://
doi.org/10.1039/C4CS00020J.
4. Zhang H., Hao S., Lin J. Influence of Li2O-
B2O3 glass on ionic migration and interfacial
properties of La2/3−xLi3xTiO3 solid electrolyte.
Journal of Alloys and Compounds. 2017. 704:
109–116. https://doi.org/10.1016/j.jallcom.
2017.02.059.
FORMATION DURING THE SYNTHESIS AND DIELECTRIC PROPERTIES OF La0.5Li0.5-xNaxTiO3
24 ISSN 2708-129X. Укр. хім. журн., 2021
PHYSICAL CHEMISTRY
5. Adachi G., Imanaka N., Aono H. Fast Li+
Conducting Ceramic Electrolytes. Advanced
Materials. 1996. 8: 127–135. https://doi.org/
10.1002/adma.19960080205.
6. Inaguma Y., Liquan C., Itoh M., Nakamura T.,
Uchida T., Ikuta H., Wakihara M. High ionic
conductivity in lithium lanthanum titanate.
Solid State Communications. 1993. 86 (10):
689–693. https://doi.org/10.1016/0038-
1098(93)90841-A.
7. García-Martín S., Morata-Orrantia A., Agu
irre M. H., Alario-Franco M. Á. Giant barrier
layer capacitance effects in the lithium ion
conducting material La0.67Li0.25Ti0.75Al0.25O3.
Applied Physics Letters. 2005. 86: 043110.
http://dx.doi.org/10.1063/1.1852717.
8. Peng Zh., Wang J., Liang P., Zhu J., Zhou X.,
Chao X., Yang Z. A new perovskite-related
ceramic with colossal permittivity and
low dielectric loss. Journal of the European
Ceramic Society. 2020. 40 (12): 4010–4015.
https://doi.org/10.1016/j.jeurceramsoc.2020.
04.030.
9. Nakamura T., Sun P.-H., Shan Y. J., Inagu
ma Y., Itoh M., Kim I.-S. On the perovskite-
related materials of high dielectric
permittivity with small temperature
dependence and low dielectric loss.
Ferroelectrics. 1997. 196 (1): 205–209. https://
doi.org/10.1080/00150199708224163.
10. Belous A.G., Ovchar O.V. Temperature
compensated microwave dielectrics based
on lithium containing titanates. Journal of
the European Ceramic Society. 2003. 23 (14):
2525–2528. https://doi.org/10.1016/S0955-
2219(03)00185-7.
11. Sanz J., Rivera A., León C., Santamaría J.,
Várez A., V’yunov O., Belous A.G. Li mo
bility in (Li,Na)yLa0.66-y/3TiO3 perovskites
(0.09<y≤0.5). A model system for the
percolation theory. Materials Research
Society. 2003. 756: 231–236. https://doi.
org/10.1557/PROC-756-EE2.3.
12. Sanjuan M. L., Laguna M. A., Belous A. G.,
V’yunov O. I. On the local structure and
lithium dynamics of La0.5(Li,Na)0.5TiO3
ionic conductors. A Raman study. Chem.
Mater. 2005. 17: 5862–5866. https://doi.
org/10.1021/cm0517770.
13. Herrero C. P., Varez A., Rivera A., Santa
marıa J., Leon C., V’yunov O., Belous A. G.,
Sanz J. Influence of vacancy ordering on
the percolative behavior of (Li1-xNax)3yLa2/3-y
TiO3 perovskites. J. Phys. Chem. B. 2005.
109: 3262–3268. https://doi.org/10.1021/
jp046076p.
14. Kambale K., Mahajan A., Butee S.P. Effect
of grain size on the properties of ceramics.
Metal Powder Report. 2019. 74 (3): 689–693.
http://dx.doi.org/10.1016/j.mprp.2019.04.060.
15. German R.M. Sintering trajectories: descrip
tion on how density, surface area, and grain
size change. The Minerals, Metals & Materials
Society. 2016. 68: 878–884. https://doi.
org/10.1007/s11837-015-1795-8.
16. Subbarao E.C. Grain size effects in ad
vanced ceramics. Colloids and Surfaces A:
Physicochemical and Engineering Aspects. 1998.
133 (1–2): 3–11. https://doi.org/10.1016/
S0927-7757(97)00104-0.
Стаття надійшла 20.05.2021.
|
| id | oai:ojs2.1444248.nisspano.web.hosting-test.net:article-310 |
| institution | Ukrainian Chemistry Journal |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-07-23T01:06:22Z |
| publishDate | 2021 |
| publisher | V.I.Vernadsky Institute of General and Inorganic Chemistry |
| record_format | ojs |
| resource_txt_mv | ucjorgua/ab/75723669947b996f90bc685f881cb1ab.pdf |
| spelling | oai:ojs2.1444248.nisspano.web.hosting-test.net:article-3102026-07-22T08:23:46Z THE SYNTHESIS IMPACT ON DIELECTRIC PROPERTIES OF La0.5Li0.5-xNaxTiO3 ВПЛИВ СИНТЕЗУ НА ДІЕЛЕКТРИЧНІ ВЛАСТИВОСТІ La0,5Li0,5-xNaxTiO3 Plutenko, Tetiana V'yunov, Oleg Fedorchuk, Oleksandr Yanchevskii, Oleg Belous, Anatolii solid solution, lithium-sodium-lanthanum titanate, perovskite, complex impedance, colossal permittivity. Using X-ray powder, diffraction the sequence of reactions occurring during the synthesis La0.5Li0.5-xNaxTiO3 by solid-state reaction technique has been determined. Using electron microscopy it has been shown that the grain size decreases with increasing x in La0.5Li0.5-xNaxTiO3 system. The influence of the grain size of ceramics on the dielectric characteristics has been indicated. The frequency dependences of permittivity and dielectric loss tangent have been investigated by ac impedance spectroscopy. It has been established that ceramic sample of La0.5Li0.4Na0.1TiO3 solid solution has the largest value of permittivity ɛ&nbsp;&gt;&nbsp;104 at wide frequency range (1–104 Hz) in La0.5Li0.5-xNaxTiO3 system. V.I.Vernadsky Institute of General and Inorganic Chemistry 2021-06-25 Article Article Physical chemistry Физическая xимия Фізична xімія application/pdf https://ucj.org.ua/index.php/journal/article/view/310 10.33609/2708-129X.87.05.2021.15-24 Ukrainian Chemistry Journal; Vol. 87 No. 5 (2021): Ukrainian Chemistry Journal; 15-24 Украинский химический журнал; ##issue.vol## 87 ##issue.no## 5 (2021): Ukrainian Chemistry Journal; 15-24 Український хімічний журнал; Том 87 № 5 (2021): Український хімічний журнал; 15-24 2708-129X 2708-1281 en https://ucj.org.ua/index.php/journal/article/view/310/169 Copyright (c) 2021 Tetiana Plutenko, Oleg V'yunov, Oleksandr Fedorchuk, Oleg Yanchevskii, Anatolii Belous https://creativecommons.org/licenses/by-nc/4.0 |
| spellingShingle | Plutenko, Tetiana V'yunov, Oleg Fedorchuk, Oleksandr Yanchevskii, Oleg Belous, Anatolii ВПЛИВ СИНТЕЗУ НА ДІЕЛЕКТРИЧНІ ВЛАСТИВОСТІ La0,5Li0,5-xNaxTiO3 |
| title | ВПЛИВ СИНТЕЗУ НА ДІЕЛЕКТРИЧНІ ВЛАСТИВОСТІ La0,5Li0,5-xNaxTiO3 |
| title_alt | THE SYNTHESIS IMPACT ON DIELECTRIC PROPERTIES OF La0.5Li0.5-xNaxTiO3 |
| title_full | ВПЛИВ СИНТЕЗУ НА ДІЕЛЕКТРИЧНІ ВЛАСТИВОСТІ La0,5Li0,5-xNaxTiO3 |
| title_fullStr | ВПЛИВ СИНТЕЗУ НА ДІЕЛЕКТРИЧНІ ВЛАСТИВОСТІ La0,5Li0,5-xNaxTiO3 |
| title_full_unstemmed | ВПЛИВ СИНТЕЗУ НА ДІЕЛЕКТРИЧНІ ВЛАСТИВОСТІ La0,5Li0,5-xNaxTiO3 |
| title_short | ВПЛИВ СИНТЕЗУ НА ДІЕЛЕКТРИЧНІ ВЛАСТИВОСТІ La0,5Li0,5-xNaxTiO3 |
| title_sort | вплив синтезу на діелектричні властивості la0,5li0,5-xnaxtio3 |
| topic_facet | solid solution lithium-sodium-lanthanum titanate perovskite complex impedance colossal permittivity. |
| url | https://ucj.org.ua/index.php/journal/article/view/310 |
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