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Akitoshi Hayashi and Masahiro Tatsumisago(Osaka Prefecture University, Japan)
Osaka Prefecture University
Development of all-solid-state lithium batteries with sulfide solid electrolytes
International Battery Association (IBA) 2013 Meeting , Barcelona, Spain March 13, 2013
2Outline
Osaka Prefecture University
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
3
Organic liquid electrolyte
L i + L i +
L i + L i +
L i +
L i +
L i +
X -
X -
X -L i + L i +
L i + L i +
anode
C Co O 2
cathode
Osaka Prefecture University
Demand for all-solid-state battery
Serious safety problems becomeobvious and thus improving safety ofbatteries (especially large-sizedbatteries) is a big issue to be solved.
Lithium-ion battery
innovative battery forthe next generation
Inorganic solid electrolyte
L i + L i +
L i +
L i +
L i +
L i + L i +
L i +
L i +
L i + L i + L i +
cathode
all-solid-state battery
anode
remove safety hazards ofleakage, volatilization and flammability
Stacked → high voltage
○high safety○long cycle life○high energy density・stacked battery・possibility of use of high
capacity electrodes(Li metal, elemental S )
Osaka Prefecture University
Solid Electrolyte
Substrate
Negative Electrode
Positive Electrode
Thin-film battery
10 m
Bulk-type battery
Positive Electrode
Solid Electrolyte
Negative Electrode
1mm
Electrode Material Conductive additive Solid Electrolyte
Consisting of powder-compressed layersof electrode and electrolyte
high energy density !
Key points:1. Solid electrolytes with high conductivity2. Favorable contact at solid-solid interface
Li / LiPON / LiCoO2
Data from the web site of Excellatron
Long cycle performance
Two types of all-solid-state rechargeable lithium batteries 4
Merits of inorganic solid electrolytes
○Single cation conduction
○Wide electrochemical window
○Simple electrochemical reactions
Why inorganic solid electrolytes? 5
in EC+DECxLi2S・(100-x)P2S5 glass M. Chiku et al., Electrochemistry, 80, 740 (2012).
(Li / electrolyte)
K. Minami et al., Solid State Ionics, 192, 122 (2011).
charge-transfer reaction at electrode
Ioni
c con
duct
ivity
Composition
Crystal
Glass○ High ionic conductivity○ Easy reduction of grain-boundary resistances○ Wide selection of compositions ○ Superionic crystalline phases are easily
precipitated from glass.
Advantages of sulfide glass electrolytes Superionic phase
Why sulfide glass solid electrolytes? 6
Cross-sectional SEM images of compressed powder pellets
Li+ = ~10-3 S cm-1
20 m
Li2S-P2S5 Li7La3Zr2O12
Oxide crystalline electrolyte
20 m
Li+ = too small (< 10-7 S cm-1)(sintered pellet: ~ 10-4 S cm-1)
Sulfide glass electrolyte
Easy deformation ofsulfide electrolytes isuseful for achievingfavorable interfacebetween electrode andelectrolyte.
Easy deformation ofsulfide electrolytes isuseful for achievingfavorable interfacebetween electrode andelectrolyte.
10-910-810-710-610-510-410-310-210-1100
1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4
Cond
uctiv
ity / S
cm-1
1000 T-1 / K -1
240 oC360 oC
Solid-state reaction
550 oC
glass
10 15 20 25 30 35 40
Inten
sity (
arb.u
nit)
2 / o (CuK)
glass
240 oC
360 oC
550 oC
Solid-statereaction
: Li7P3S11
: Li3.2P0.96S4 : Li4P2S6
: Li3PS4
7
F. Mizuno et al., Adv. Mater., 17, 918 (2005); Solid State Ionics., 177, 2721 (2006). Osaka Prefecture University
Precipitation of superionic Li7P3S11 phase from the 70Li2S・30P2S5 (mol%) glass
The formation of a superionicmetastable phase is responsiblefor increasing conductivity ofglass-based solid electrolytes.
Liquid electrolytes
Conductivi
ty/ S
cm
-1
Temperature ( oC )
Li2O-B2O3-LiCl glass
Li2O-Nb2O5 glass
Li3.4V0.4Ge0.6O4crystal
La0.51Li0.34TiO2.94 crystal
Li3N crystal
Li2S-SiS2-P2S5-LiI glass
Li1.3Al0.3Ti1.7(PO4)3 crystal
Li3.3PO3.8N0.22 glass (LiPON)
1000 T-1 / K-1
25100200300 0
1.5 2 2.5 3 3.5
10 0
10 -1
10 -2
10 -3
10 -5
10 -4
10 -6
Li3.25P0.75Ge0.25S4thio-LISICON II Li7P3S11 glass-ceramic
25= 5 x 10-3 Scm-1
Li+ ion conductivity of thesulfide solid electrolytesis now higher than that ofliquid electrolytes!
Li7P3S11 glass-ceramic25= 1 x 10-2 Scm-1
Seino et al., 36th Solid State Ionics Meeting in Japan (2010).
Li10GeP2S12 crystal
Kamaya, Kanno et al, Nat. Mater., 10, 682 (2011).
25= 1.2 x 10-2 Scm-1
8Solid electrolytes with high lithium ion conductivity
T. Minami ed., “Solid State Ionics for Batteries”, Springer, Tokyo, p. 1 (2005).
Adv. Mater., 17, 918 (2005). J. Non-Cryst. Solids, 356, 2670 (2010).
Osaka Prefecture University
0
0.5
1
1.5
2
2.5
60 70 80 90 100Mol % Li2S
H 2S am
ount
/ cm
3 g-1 (1
min
)
200300400500600700
Inte
nsity
(arb
. uni
t)
Wavenumber / cm -1
PS43
75Li2S・25P2S5 glass
before
PS43
PS43 S S
S
S
P
Main structural unit (PS43-) did not
change after exposure to air for 1day.
after exposure to air for 1day
Chemical stability in air of sulfide electrolytes
Osaka Prefecture UniversityH. Muramatsu et al., Solid State Ionics, 182 (2011) 116.
Hydrolysis is suppressed.
H2S generation (R.H. 50%)
Sulfide solid electrolytes with moderate chemical stability in air atmosphereare prepared by selecting compositions.
9
Li2S-P2S5 glasses
10Outline
Osaka Prefecture University
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
11
Li2S-P2S5 glass-ceramic
Stainless-steel(current collector)
Polycarbonate(insulator)
conductive additiveactive materialSE = 60 : 40 : 4 (wt %)
Composite electrode
Osaka Prefecture University
Solid electrolyte (SE):
Application to bulk-type all-solid-state batteriesApplication to bulk-type all-solid-state batteries
The formation of Li+ and e-
conduction paths to activematerial particles is significant.
Counter electrode:Li-In alloy(reference electrode)
Working electrode: e.g. Li4Ti5O12
screw
Li+
e-
Li-In / 70Li2S・29P2S5・1P2S3 glass-ceramic / Li4Ti5O12
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.
Osaka Prefecture University
100 oC
K. Minami et al., Solid State Ionics, 192 (2011) 122.
12Electrochemical performance of bulk-type solid-state batteries
12.8
13Approaches to fabricate favorable electrode-electrolyte interfaces
Li / S batteries
M. Tatsumisago, M. Nagao, A. Hayashi. Journal of Asian Ceramic Societies, in press.
Ar filled glove box
KrF excimer laser( = 248 nm)
Vacuum chamber
Target Pellet of mixture of Li2S and P2S5 crystalline powder(80Li2S・20P2S5 mol%)
Ambient gas Ar gas (5 Pa)Temperature Room temperatureFrequency 10 HzLaser fluence 2 J cm-2
Target-substrate distance 7 cm
Deposition conditions
14Sulfide electrolyte coating on LiCoO2 electrode by PLD
vibrator
Li2S-P2S5 electrolyteLiNbO3-coated
LiCoO2*
Li2S-P2S5 target
KrF Excimer laser (248 nm)
Surface coating using PLD
PLD
(80Li2S・20P2S5)
* N. Ohta, K. Takada et al. Electrochem. Commun. 9, 1486 (2007).
LiCoO2 positive electrode
Li2S-P2S5 electrolyte
All-solid-state cells using SE-coated LiCoO2
A. Sakuda et al, J. Power Sources, 196 (2011) 6735.
1
2
3
4
5
0 20 40 60 80 100 120
Cel
l vol
tage
/ V
Capacity / mAh g-1 (LiCoO2+Li2S-P2S5)
With SE particlesWith SE coatings
With SE particles(30 wt% SE particles were mixed)
With SE coatings(10 wt% SE films were coated)
In / Li2S-P2S5 / LiCoO20.13 mA cm-2
Lithium-ion conducting paths are formed with small amounts of solid electrolytes.
5 m
LiCoO2
LiCoO2
LiCoO2
Li2S-P2S5
LiCoO2
Cross-sectional SEM image
15
Sulfur positive electrode in all-solid-state cells shows a good cycle performance.
All-solid-state Li / S batteries 16
M. Nagao, A. Hayashi, M. Tatsumisago, Electrochim. Acta, 56, 6055 (2011).
In / LiCoO2
25oC0.064 mA cm-2
2
1
0
3
4
5
0 400 800 1200 1600
Cell p
oten
tial v
s. Li
/ V
Capacity / mAh g-1
Li-In / S
charge
discharge
S + xLi+ + xe- LixSdischarge
charge
Sulfur active material・abundant element・large theoretical capacity
(1672 mAh g-1)
Li-In / 80Li2S・20P2S5 (SE) / 25S・25AB・50SE (wt%)
Li-In / SE / 50S・20AB・30SE (wt%)
25 oC
0.064 mA cm-2
0.64 mA cm-2 (0.2 C)
0.064 mA cm-2
0 10 20 30 40 500
200
400
600
800
1000
1200
1400
Cycle number
Capa
city /
mAh
g-1
(sul
fur)
17
M. Nagao et al., Energy Technology, in press.
Increase of the sulfur content in a positive electrode
Ball-milling the S-AB composite at 155oC(the lowest viscosity coefficient of sulfur)
200 nm
C; blue, P; green, S; red
e-
e-
e-
Li+e-
Li+
Li+
Li+
AB
sulfur
Li2S-P2S5SE
Cross-sectional EELS mapping
・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
18Outline
Osaka Prefecture University
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
Why Na batteries?
Sodium-sulfur (NAS) batteries ・Large energy density (760 Wh kg-1)・High-temperature operation (>300 oC)・Strict security apparatus
Na / sintered -alumina / S(liquid) (solid) (liquid)
Limitation of usage environment
Na+ ion batteries
Next-generation batterieswith high energy densityusing abundant sodiumsources
19
*
*J.O. Besenhard and M. Winter, CHEMPHYSCHEM, 3, 155 (2002).
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
10-6
10-5
10-4
10-3
10-2
10-1
2 2.5 3 3.5
Cond
uctiv
ity / S
cm-1
1000 T-1 / K-1
Glass
Glass-ceramic
75Na2S・25P2S5 (mol%) = Na3PS4
Conductivity increases by crystallization of the Na3PS4 glass.
A. Hayashi et al., Nature Communications, 3 (2012) 856.
New Na+ ion conducting sulfide electrolytes 20
A cubic Na3PS4 phase, which has notbeen reported, is precipitated inthe glass-ceramic electrolyte.
XRDConductivity
25 = 2×10-4 S cm-1
Osaka Prefecture University
The all-solid-state sodium battery with the Na3PS4 electrolyte ischarged and discharged for 10 cycles and shows a good cycleabilityat room temperature.
25 oC, 0.013 mA cm-2, 1.17-2.40 V
Cell p
otenti
al vs
. Na-
Sn / V
cubic-Na3PS4glass-ceramic
Stainless steel(current collector)
Solid electrolyte (SE):
Counter/reference electrode: Na-Sn alloy
Working electrode: TiS2:SE=2:3 (wt ratio)
Na-Sn / Na3PS4 / TiS2Na-Sn / Na3PS4 / TiS2
Application to all-solid-state sodium batteries 21
Osaka Prefecture UniversityA. Hayashi et al., Nature Communications, 3 (2012) 856.
Summary
1. Sulfide glass-based materials have favorable properties as solidelectrolyte for bulk-type all-solid-state batteries. Especially, the glass-ceramics 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 beendeveloped by the modification of the electrode-electrolyte interface.
3. Cubic-Na3PS4 glass-ceramic electrolyte with the conductivity of 10-4 Scm-1 is prepared and all-solid-state Na batteries with the electrolyteoperate 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.