Journal of the American Ceramic Society,
Journal Year:
2024,
Volume and Issue:
107(7), P. 4949 - 4961
Published: March 31, 2024
Abstract
Lead‐free
potassium
sodium
niobate
(KNN)
ferroelectrics
have
emerged
as
promising
alternatives
to
lead‐based
materials
due
their
reduced
toxicity
and
sometimes
enhanced
properties.
The
opportunity
modify
the
ferroelectric
properties
by
doping,
nevertheless,
differs
from
ceramics.
A
much
lower
impact
with
increasing
dopant
concentration
was
observed.
This
study
systematically
investigates
differences
in
defect
chemistry
of
Na
0.475
K
Li
0.065
Nb
0.92
Ta
0.08
O
3
ceramics
through
iron
(Fe)
acceptor
doping
calcium
(Ca)
donor
at
varying
concentrations.
From
chemical
point
view,
it
becomes
evident
that
intrinsic
defects
on
electrical
exceeds
effect
extrinsic
induced
doping.
performance
donor‐doped
(Ca
2+
)
closely
resembles
undoped
KNN.
Thus,
hardly
any
change
conductivity
is
For
Fe‐doped
samples,
its
contribution
dielectric
loss
increased,
which
not
benefit
an
application
a
ferroelectric.
Therefore,
concepts
“softening”
“hardening”
are
incompatible
regularly
sintered
KNN
ACS Applied Materials & Interfaces,
Journal Year:
2023,
Volume and Issue:
15(44), P. 51421 - 51428
Published: Oct. 27, 2023
Donor
and
acceptor
ions
serving
as
extrinsic
defects
in
piezoelectrics
are
mostly
used
to
improve
the
performance
merits
satisfy
industrial
application.
However,
conventional
doping
strategy
is
unable
overcome
inherent
trade-off
between
piezoelectric
coefficient
(d33)
mechanical
quality
factor
(Qm).
Herein,
inspired
by
valence
state
variation
observed
manganese
oxides
during
sintering,
this
study
focuses
on
manipulating
intrinsic
oxygen
vacancies
potassium
sodium
niobate
(KNN)
ceramics
via
heat
treatment.
The
annealing
process
results
a
simultaneous
improvement
both
d33
(20%)
Qm
(80%),
leading
comparable
with
commercial
PZT-5A
enabling
their
application
atomizer
components.
Moreover,
mechanism
of
occupation
diffusion
proposed
an
extended
X-ray
absorption
fine
structure
density
functional
theory
analysis.
improved
electromechanical
annealed
KNN
ceramic
associated
optimized
redistribution
donor
defects,
which
facilitated
recombination
vacancies.
This
work
breaks
longstanding
obstacles
comprehending
existing
forms
offers
potential
popularizing
KNN-based
piezoceramics
replace
traditional
PZT
lead-based
counterparts
market.
Advanced Functional Materials,
Journal Year:
2023,
Volume and Issue:
33(38)
Published: June 3, 2023
Abstract
Hard‐type
piezoceramics
are
key
materials
in
high‐power
transducers
and
transformers.
Acceptor
doping
is
the
most
widely
used
piezoelectric
hardening
approach,
but
mobility
of
oxygen
vacancies
at
large
electric
fields
or
high
temperatures
inevitably
leads
to
deterioration
performance.
The
present
study
proposes
a
new
method
associated
with
intragranular
metal
particles
for
achieving
strong
pinning
ferroelectric
domain
walls.
Highly
effective
via
Ag
Ba
0.85
Ca
0.15
Ti
0.90
Zr
0.10
O
3
ceramic
realized,
where
mechanical
quality
factor
Q
m
coercive
field
E
c
increase
by
170%
53%,
respectively.
/0.10Ag
sample
features
larger
than
pure
.
Moreover,
properties
(
d
31
k
)
show
exceptional
stability
vibration
velocity.
This
composite
approach
introducing
can
be
considered
as
generic
extended
other
systems.
SusMat,
Journal Year:
2023,
Volume and Issue:
4(1), P. 116 - 125
Published: Dec. 25, 2023
Abstract
Dielectric
capacitors
with
a
fast
charging/discharging
rate,
high
power
density,
and
long‐term
stability
are
essential
components
in
modern
electrical
devices.
However,
miniaturizing
integrating
face
persistent
challenge
improving
their
energy
density
(
W
rec
)
to
satisfy
the
specifications
of
advanced
electronic
systems
applications.
In
this
work,
leveraging
phase‐field
simulations,
we
judiciously
designed
novel
lead‐free
relaxor
ferroelectric
material
for
enhanced
storage
performance,
featuring
flexible
distributed
weakly
polar
endotaxial
nanostructures
(ENs)
embedded
within
strongly
fluctuation
matrix.
The
matrix
contributes
substantially
polarization
under
an
external
electric
field,
randomly
dispersed
ENs
effectively
optimize
breakdown
phase
proportion
provide
strong
restoring
force,
which
advantageous
bolstering
strength
minimizing
hysteresis.
Remarkably,
system
incorporating
achieves
exceptionally
value
10.3
J/cm
3
,
accompanied
by
large
efficiency
η
85.4%.
This
work
introduces
promising
avenue
designing
new
materials
capable
capacitive
exceptional
performance
characteristics.
Journal of the American Ceramic Society,
Journal Year:
2024,
Volume and Issue:
107(7), P. 4949 - 4961
Published: March 31, 2024
Abstract
Lead‐free
potassium
sodium
niobate
(KNN)
ferroelectrics
have
emerged
as
promising
alternatives
to
lead‐based
materials
due
their
reduced
toxicity
and
sometimes
enhanced
properties.
The
opportunity
modify
the
ferroelectric
properties
by
doping,
nevertheless,
differs
from
ceramics.
A
much
lower
impact
with
increasing
dopant
concentration
was
observed.
This
study
systematically
investigates
differences
in
defect
chemistry
of
Na
0.475
K
Li
0.065
Nb
0.92
Ta
0.08
O
3
ceramics
through
iron
(Fe)
acceptor
doping
calcium
(Ca)
donor
at
varying
concentrations.
From
chemical
point
view,
it
becomes
evident
that
intrinsic
defects
on
electrical
exceeds
effect
extrinsic
induced
doping.
performance
donor‐doped
(Ca
2+
)
closely
resembles
undoped
KNN.
Thus,
hardly
any
change
conductivity
is
For
Fe‐doped
samples,
its
contribution
dielectric
loss
increased,
which
not
benefit
an
application
a
ferroelectric.
Therefore,
concepts
“softening”
“hardening”
are
incompatible
regularly
sintered
KNN
