Abstract
Anionic
redox
chemistry
has
attracted
increasing
attention
for
the
improvement
in
reversible
capacity
and
energy
density
of
cathode
materials
Li/Na‐ion
batteries.
However,
adverse
electrochemical
behaviors,
such
as
voltage
hysteresis
sluggish
kinetics
resulting
from
weak
metal‐ligand
interactions,
commonly
occur
with
anionic
reactions.
Currently,
mechanistic
investigation
driving
these
issues
still
remains
foggy.
Here,
we
chemically
designed
Na
0.8
Fe
0.4
Ti
0.6
S
2
O
model
cathodes
to
explore
covalency
effects
on
interactions
during
process.
strengthened
covalent
interaction
bonds
exhibits
smaller
faster
than
(de)sodiation
Theoretical
calculations
suggest
that
is
dominant
redox‐active
center
,
whereas
moves
removal
+
.
We
attribute
above
different
behaviors
between
charge
transfer
ligand
metal.
Moreover,
structural
stability
enhanced
by
cation
migration
barriers
through
strong
desodiation.
These
insights
into
originality
provide
guidance
design
high‐capacity
structurally
stable
Advanced Materials,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 15, 2025
Abstract
The
energy
density
of
layered
oxides
Li‐ion
batteries
can
be
enhanced
by
inducing
oxygen
redox
through
replacing
transition
metal
(TM)
ions
with
Li
in
the
TM
layer.
Undesirably,
cathodes
always
suffer
from
unfavorable
structural
degradation,
which
is
closely
associated
irreversible
migration
and
slab
gliding,
resulting
continuous
capacity
voltage
decay.
Herein,
attention
paid
to
layer
(Li
)
find
their
extra
effects
beyond
redox,
has
been
rarely
mentioned.
With
aid
7
solid‐state
NMR
functional
theory
(DFT)
calculations,
controllable
verified.
mystery
uncovered
that
preferential
plays
an
imperative
role
preventing
transformation
postponing
gliding
structure.
Integrated
inhibited
migration,
robustness
reversibility
2
RuO
3
drastically
improved
after
Zr‐substitution,
providing
a
solid
foundation
for
achieving
ultra‐stable
electrochemical
performance
even
thousands
cycles
(2500
cycles).
discovery
highlights
significance
respect
provides
potential
route
toward
high‐energy‐density
batteries.
Abstract
O3‐type
cathodes
with
sufficient
Na
content
are
considered
as
promising
candidates
for
sodium‐ion
batteries
(SIBs).
However,
these
suffer
from
insufficient
utilization
of
the
active
elements,
restraining
delivered
capacity.
In
this
work,
a
high
entropy
strategy
is
applied
to
typical
O3
cathode
NaLi
0.1
Ni
0.35
Mn
0.55
O
2
(NLNM),
forming
oxide
0.15
Cu
Mg
Ti
0.2
(Na‐HE).
Results
show
that
elements
fully
exploited
in
Na‐HE,
two‐electron
reaction
by
2+/4+
(further
extended
redox
and
even
oxygen
redox),
vastly
different
one‐electron
2+/3+
NLNM.
The
full
dramatically
improves
output
capacity
(122.6
mAh
g
−1
Na‐HE
versus
81
NLNM).
Moreover,
detrimental
phase
transition
well
suppressed
Na‐HE.
exhibits
retention
88.7%
after
100
cycles
at
130
mA
,
compared
only
36.4%
These
findings
provide
new
insight
design
materials
SIBs
energy
density
robust
stability.
Advanced Functional Materials,
Год журнала:
2025,
Номер
unknown
Опубликована: Фев. 18, 2025
Abstract
Revealing
interlayer
oxygen
charge
is
of
great
significance
in
understanding
the
high‐voltage
and
air
stability
sodium
layered
cathodes,
but
it
currently
lacks
attention.
Particularly,
ion
full
batteries
under
high
cathode
loading
(≥8
mg
cm
−2
)
also
faces
extremely
challenges.
Here,
its
mechanism
for
are
revealed
a
high‐entropy
O3‐Na
0.85
Li
0.1
Al
0.02
Sn
0.08
Cu
Ti
Ni
0.3
Mn
O
2
(HEO)
cathode,
which
enables
robust
high‐cathode‐loading
sodium‐ion
batteries.
The
doping
effectively
maintains
transition
metal
(TM)─O
bond
covalency,
stabilizing
charge.
stable
O─O
repulsion
avoids
structural
collapse,
realizing
P3‐OP2‐P3
reversible
phase
transition.
Moreover,
reduced
achieves
Na
layer
contraction
Na─O
enhancement.
These
features
inhibit
attack
water
loss,
well
stability.
Therefore,
HEO
exhibits
good
up
to
900
cycles
2.0‒4.3
V
high‐capacity
retention
96.12%
after
5
day
exposure.
pouch
cell
with
≈16
≈60
mAh
lasts
100
cycles.
This
work
contributes
new
insights
into
both
cathodes
practical
Nano-Micro Letters,
Год журнала:
2025,
Номер
17(1)
Опубликована: Март 10, 2025
Abstract
The
transition
to
renewable
energy
sources
has
elevated
the
importance
of
SIBs
(SIBs)
as
cost-effective
alternatives
lithium-ion
batteries
(LIBs)
for
large-scale
storage.
This
review
examines
mechanisms
gas
generation
in
SIBs,
identifying
from
cathode
materials,
anode
and
electrolytes,
which
pose
safety
risks
like
swelling,
leakage,
explosions.
Gases
such
CO
2
,
H
O
primarily
arise
instability
side
reactions
between
electrode
electrolyte,
electrolyte
decomposition
under
high
temperatures
or
voltages.
Enhanced
mitigation
strategies,
encompassing
design,
buffer
layer
construction,
material
optimization,
are
deliberated
upon.
Accordingly,
subsequent
research
endeavors
should
prioritize
long-term
high-precision
detection
bolster
performance
thereby
fortifying
their
commercial
viability
furnishing
dependable
solutions
storage
electric
vehicles.
