International Battery Association (IBA) 2013 Meeting , Barcelona, Spain
March 13, 2013
Development of all-solid-state lithium batteries
with sulfide solid electrolytes
Akitoshi Hayashi and Masahiro Tatsumisago
(Osaka Prefecture University, Japan)
Osaka Prefecture University
Outline
2
1. Background
Motivation of all-solid-state rechargeable batteries
2. Sulfide glass solid electrolytes
3. All-solid-state Li batteries with sulfide electrolytes
Approaches to fabricate favorable electrode-electrolyte interfaces
4. Na+ ion conductors for all-solid-state Na batteries
5. Summary
Osaka Prefecture University
Demand for all-solid-state battery
Organic liquid electrolyte
anode
C
anode
cathode
Co O 2
Li+ Li+ Li+
Li+
XLi+ Li+
Li+ Li+
X- Li+
Li+ Li+
Inorganic solid electrolyte
cathode
X-
3
Lithium-ion battery
remove safety hazards of
leakage, volatilization and
flammability
+
Li+ Li+ Li Li+ Li+ Li+
+
+
L i + L i L iL+i
Li+ Li+
all-solid-state battery
innovative battery for
the next generation
○high safety
○long cycle life
○high energy density
Serious safety problems become
obvious and thus improving safety of
・stacked battery
・possibility of use of high
batteries (especially large-sized
capacity electrodes
batteries) is a big issue to be solved.
Stacked → high voltage （Li metal, elemental S ）
Osaka Prefecture University
Two types of all-solid-state rechargeable lithium batteries
4
Li / LiPON / LiCoO2
Thin-film battery
Negative Electrode
Solid Electrolyte
Long cycle performance
10 m
Substrate
Positive Electrode
Data from the web site of Excellatron
Bulk-type battery
Consisting of powder-compressed layers
of electrode and electrolyte
Negative
Electrode
Solid
Electrolyte
Positive
Electrode
Electrode Material
1mm
high energy density !
Key points:
1. Solid electrolytes with high conductivity
2. Favorable contact at solid-solid interface
Conductive additive Solid Electrolyte
Osaka Prefecture University
Why inorganic solid electrolytes?
Merits of inorganic solid electrolytes
5
charge-transfer reaction at electrode
○Single cation conduction
○Wide electrochemical window
○Simple electrochemical reactions
(Li / electrolyte)
xLi2S・(100-x)P2S5 glass in EC+DEC
K. Minami et al., Solid State Ionics, 192, 122 (2011).
M. Chiku et al., Electrochemistry, 80, 740 (2012).
Why sulfide glass solid electrolytes?
Superionic phase
High ionic conductivity
Easy reduction of grain-boundary resistances
Wide selection of compositions
Superionic crystalline phases are easily
precipitated from glass.
Cross-sectional SEM images of compressed powder pellets
Sulfide glass electrolyte
Li2S-P2S5
Ionic conductivity
Advantages of sulfide glass electrolytes
○
○
○
○
Oxide crystalline electrolyte
Li7La3Zr2O12
20 m
Li+ = ～10-3 S cm-1
6
20 m
Li+ = too small (< 10-7 S cm-1)
(sintered pellet: ～ 10-4 S cm-1)
Glass
Crystal
Composition
Easy deformation of
sulfide electrolytes is
useful for achieving
favorable
interface
between electrode and
electrolyte.
Precipitation of superionic Li7P3S11 phase from the 70Li2S・30P2S5 (mol%) glass
7
Solid-state
reaction
550 oC
360 oC
240 oC
glass
10
15
20
25
30
o
2 / (CuK)
35
40
Conductivity / S cm
: Li4P2S6
Intensity (arb.unit)
: Li3.2P0.96S4
: Li7P3S11
: Li3PS4
-1
0
10
-1
10
-2
10
-3
10
-4
10
-5
10
-6
10
-7
10
-8
10
-9
10
1.8
360 o C
240 o C
glass
550 o C
Solid-state reaction
2
2.2 2.4 2.6 2.8
3
3.2 3.4
1000 T -1 / K -1
The formation of a superionic
metastable phase is responsible
for increasing conductivity of
glass-based solid electrolytes.
F. Mizuno et al., Adv. Mater., 17, 918 (2005); Solid State Ionics., 177, 2721 (2006). Osaka
Prefecture University
Solid electrolytes with high lithium ion conductivity
Li10GeP2S12 crystal
25= 1.2 x 10-2 Scm-1
Li7P3S11 glass-ceramic
25= 1 x 10-2 Scm-1
Kamaya, Kanno et al, Nat. Mater.,
10, 682 (2011).
Conductivity / S cm-1
10
0
10
-1
10
-2
Temperature ( oC )
200
100
25
300
Li1.3Al0.3Ti1.7(PO4)3 crystal
Li2S-SiS2-P2S5-LiI glass
10
-5
10 -6
1.5
0
Li3.25P0.75Ge0.25S4
thio-LISICON II
Liquid electrolytes
Li7P3S11 glass-ceramic
25= 5 x 10-3 Scm-1
Adv. Mater., 17, 918 (2005).
J. Non-Cryst. Solids, 356, 2670 (2010).
10 -3
10 -4
Seino et al., 36th Solid
State Ionics Meeting
in Japan (2010).
Li3.4V0.4Ge0.6O4
crystal
Li3N crystal
La0.51Li0.34TiO2.94 crystal
Li2O-Nb2O5 glass
Li2O-B2O3-LiCl glass
Li3.3PO3.8N0.22 glass (LiPON)
2
2.5
3
1000 T-1 / K-1
3.5
T. Minami ed., “Solid State Ionics for Batteries”, Springer, Tokyo, p. 1 (2005).
Li+ ion conductivity of the
sulfide solid electrolytes
is now higher than that of
liquid electrolytes!
Osaka Prefecture University
8
Chemical stability in air of sulfide electrolytes
PS43
PS43
S
P
2.5
S
S
PS43
600
500
400
300
Wavenumber / cm -1
200
H2S generation
2
(R.H. 50%)
1.5
1
0.5
0
before
700
H2S amount / cm3 g-1 (1min)
Intensity (arb. unit)
after exposure
to air for 1day
Li2S-P2S5 glasses
S
75Li2S･25P2S5 glass
9
60
70
80
Mol % Li 2S
90
100
Main structural unit (PS43-) did not
change after exposure to air for 1day.
Hydrolysis is suppressed.
Sulfide solid electrolytes with moderate chemical stability in air atmosphere
are prepared by selecting compositions.
H. Muramatsu et al., Solid State Ionics, 182 (2011) 116.
Osaka Prefecture University
Outline
10
1. Background
Motivation of all-solid-state rechargeable batteries
2. Sulfide glass solid electrolytes
3. All-solid-state Li batteries with sulfide electrolytes
Approaches to fabricate favorable electrode-electrolyte interfaces
4. Na+ ion conductors for all-solid-state Na batteries
5. Summary
Osaka Prefecture University
Application to bulk-type all-solid-state batteries
Stainless-steel
(current collector)
Working electrode: e.g. Li4Ti5O12
Solid electrolyte (SE):
Li2S-P2S5 glass-ceramic
Polycarbonate
(insulator)
screw
Composite electrode
Li+
eSE
active material
Counter electrode：Li-In alloy
(reference electrode)
The formation of Li+ and econduction paths to active
material particles is significant.
conductive additive = 60 : 40 : 4 (wt %)
Osaka Prefecture University
11
Electrochemical performance of bulk-type solid-state batteries
Li-In / 70Li2S･29P2S5･1P2S3 glass-ceramic / Li4Ti5O12
100 oC
12.8
The cell operated at a high current density of 12.8 mA cm-2
and kept the capacity of 130 mAh g-1 for 700 cycles.
K. Minami et al., Solid State Ionics, 192 (2011) 122.
Osaka Prefecture University
12
Approaches to fabricate favorable electrode-electrolyte interfaces
13
Li / S
batteries
M. Tatsumisago, M. Nagao, A. Hayashi.
Journal of Asian Ceramic Societies, in press.
Sulfide electrolyte coating on LiCoO2 electrode by PLD
KrF excimer laser
（ = 248 nm）
14
Surface coating using PLD
Li2S-P2S5 target
(80Li2S･20P2S5)
KrF Excimer laser
(248 nm)
Vacuum chamber
Ar filled glove box
Deposition conditions
Target
Pellet of mixture of Li2S
vibrator
and P2S5 crystalline powder
（80Li2S･20P2S5 mol%）
Ambient gas
Ar gas (5 Pa)
Temperature
Room temperature
Frequency
10 Hz
Laser fluence
2 J cm-2
Target-substrate distance 7 cm
PLD
LiNbO3-coated
LiCoO2*
Li2S-P2S5 electrolyte
* N. Ohta, K. Takada et al. Electrochem. Commun. 9, 1486 (2007).
All-solid-state cells using SE-coated LiCoO2
5
LiCoO2 positive
electrode
Cell voltage / V
4
Li2S-P2S5 electrolyte
3
2
Cross-sectional SEM image
LiCoO2
LiCoO2
Li2S-P2S5
In / Li2S-P2S5 / LiCoO2
0.13 mA cm-2
1
With SE particles
With SE coatings
0
20
40
60
80 100 120
-1
Capacity / mAh g (LiCoO2+Li2S-P2S5)
LiCoO2
LiCoO2
5 m
Lithium-ion conducting paths are formed
with small amounts of solid electrolytes.
With SE particles
With SE coatings
(30 wt% SE particles
(10 wt% SE films
were mixed)
were coated)
A. Sakuda et al, J. Power Sources, 196 (2011) 6735.
15
All-solid-state Li / S batteries
・abundant element
・large theoretical capacity
(1672 mAh g-1)
S+
xLi+
+
xe-
discharge
charge
LixS
Li-In / 80Li2S・20P2S5 (SE) / 25S・25AB・50SE (wt%)
5
Cell potential vs. Li / V
Sulfur active material
16
4
In / LiCoO2
3
charge
2
discharge
1
0
Li-In / S
25oC
0.064 mA cm-2
0
400
800
1200
1600
Capacity / mAh g-1
Sulfur positive electrode in all-solid-state cells shows a good cycle performance.
M. Nagao, A. Hayashi, M. Tatsumisago, Electrochim. Acta, 56, 6055 (2011).
Increase of the sulfur content in a positive electrode
Li-In / SE / 50S・20AB・30SE (wt%)
17
C; blue, P; green, S; red
Ball-milling the S-AB composite at 155oC
(the lowest viscosity coefficient of sulfur)
Capacity / mAh g-1 (sulfur)
1400
1200
1000
0.064
mA cm-2
0.064 mA cm-2
800
600
200 nm
Cross-sectional
EELS mapping
400
200
0
25
0
0.64
oC
10
mA cm-2
20
30
Cycle number
Li＋ e－
(0.2 C)
40
AB
Li＋
sulfur
50
・Energy density based on the weight of the total
positive electrode is increased (1007 Wh kg-1).
・Sulfur with the size less than 200 nm and AB
particles are homogeneously dispersed in the SE
matrix.
large capacity & good cyclability
e－
e－ Li＋ －
e
Li＋
Li2S-P2S5
SE
M. Nagao et al., Energy Technology, in press.
Outline
18
1. Background
Motivation of all-solid-state rechargeable batteries
2. Sulfide glass solid electrolytes
3. All-solid-state Li batteries with sulfide electrolytes
Approaches to fabricate favorable electrode-electrolyte interfaces
4. Na+ ion conductors for all-solid-state Na batteries
5. Summary
Osaka Prefecture University
Why Na batteries?
Na+ ion batteries
19
*
Next-generation batteries
with high energy density
using abundant sodium
sources
*J.O. Besenhard and M. Winter, CHEMPHYSCHEM, 3, 155 (2002).
Sodium-sulfur (NAS) batteries
・Large energy density (760 Wh kg-1)
Na / sintered -alumina / S
(liquid)
(solid)
(liquid)
・High-temperature operation (＞300 oC)
・Strict security apparatus
Limitation of usage environment
All-solid-state Na/s batteries operating at room temperature are
strongly desirable from safety point of view.
New solid electrolytes suitable for solid-state batteries
Osaka Prefecture University
New Na+ ion conducting sulfide electrolytes
20
75Na2S･25P2S5 (mol%) = Na3PS4
Conductivity
-1
Conductivity / S cm
-1
10
XRD
Glass-ceramic
-2
10
-3
10
-4
10
-5
10
Glass
-6
10
2
2.5
3
1000 T-1 / K-1
3.5
Conductivity increases by crystallization
of the Na3PS4 glass.
25 = 2×10-4 S cm-1
A. Hayashi et al., Nature Communications, 3 (2012) 856.
A cubic Na3PS4 phase, which has not
been reported, is precipitated in
the glass-ceramic electrolyte.
Osaka Prefecture University
Application to all-solid-state sodium batteries
Stainless steel
(current collector)
Solid electrolyte (SE):
cubic-Na3PS4
glass-ceramic
Counter/reference
electrode:
Na-Sn alloy
Cell potential vs. Na-Sn / V
Working electrode:
TiS2：SE=2:3
(wt ratio)
Na-Sn / Na3PS4 / TiS2
25 oC, 0.013 mA cm-2, 1.17-2.40 V
The all-solid-state sodium battery with the Na3PS4 electrolyte is
charged and discharged for 10 cycles and shows a good cycleability
at room temperature.
A. Hayashi et al., Nature Communications, 3 (2012) 856.
Osaka Prefecture University
21
Summary
1. Sulfide glass-based materials have favorable properties as solid
electrolyte for bulk-type all-solid-state batteries. Especially, the glassceramics in the system Li2S-P2S5 show high Li+ ion conductivities of 10-3
to 10-2 S cm-1, which are higher than those of liquid electrolytes.
2. Electrochemical performance of all-solid-state Li batteries has been
developed by the modification of the electrode-electrolyte interface.
3. Cubic-Na3PS4 glass-ceramic electrolyte with the conductivity of 10-4 S
cm-1 is prepared and all-solid-state Na batteries with the electrolyte
operate at room temperature.
Acknowledgements
This work was financially supported by
・Grant-in-Aid for Scientific Research from MEXT
・CREST and ALCA projects from JST
・Toyota Motor Co.