Transcript Nowe zaprojektowane sole jako elektrolity do baterii litowych

Designing new
polymeric electrolytes
for Lithium – Ion
Battery Applications
Outline
• Polymer electrolytes advantages and drawbacks
• Composite polymeric electrolytes: fillers and anion receptors
• Role of salt anions
• New types of imidazole salts
• Conclusions
Alistore ERI |
www.alistore.eu
Polymer Electrolytes
•
•
Li+
PEO
•
•
•
•
Electrodonor polymers
O,N,S (sufficient donor ability for
complexation)
Sufficient distance between sites
Amorphous
Polyethers - good candidates
Low Tg (flexibility)
General classification
Polymer Complexes
Polymer Gels
Polyelectrolytes (Single Ion Conductors)
Copyrights Marek Marcinek
Solid Polymer Electrolytes Advantages
• nonvolatility,
• no decomposition at the electrodes,
• no possibility of leaks,
• use of metallic lithium in secondary cells (lithium dendrites growing on
the electrode surface would be stopped by the non-porous and solid
electrolyte),
• lowering the cell price (PEO is cheaper than organic carbonates; it could
be used as a binder for electrodes to improve the compatibility of
consecutive layers; moreover fabrication of such a cell would be easier –
cost),
• strengthening of cells thanks to the all-solid-state construction,
• shape flexibility,
• lowering the cell weight – non-volatile, all-solid-state cells don’t need
heavy steel casing,
• improved shock resistance,
• better overheat and overcharge allowance,
• improved safety!!!
Limitations of polymeric electrolytes
low cationic transference number (close to 0.1-0.3) of most conventional
P(EO)-LiX polymer electrolytes,
forming of highly resistive layers at the anode-electrolyte interface,
high degree of crystallinity of PEO based electrolytes,
conductivity at ambient temperature not high enough for application in
batteries.
Composite electrolytes
Three component systems:
polymer
PEO-DME - (Mw=500) dicapped with methyl groups
Lithium salt
LiClO4, LiNTFSi, LiCF3SO3, LiI, LiBF4
filler able to impact ion-ion and ion-polymer
interaction
•Ceramic fillers
•Triphenylborane
•Calixarene
•Calix[6]pyrolle
Conductivity
-3
log  / S cm-1
-4
PEGME-LiClO4
PEGME-LiClO4 -Al2O3neutral
PEGME-LiClO4 -Al2O3basidic
PEGME-LiClO4 -Al2O3acidic
-5
-6
-7
10-5
10-4
10-3
10-2
c / mol kg-1
10-1
100
Viscosity as a function of salt
concentration
100
PEODME-LiClO4 4 mol kg -1
100
PEODME-LiClO4-Al2O3 oboj. 4 mol kg -1
PEGME-LiClO4 3 mol kg -1
PEGME-LiClO4-Al2O3 kw. 3 mol kg -1
lepkoњж/ Pa s
 / Pa s
PEGME-LiClO4-Al2O3 oboj. 3 mol kg -1
10
10
1
PEGME-LiClO4-Al2O3 zas. 3 mol kg -1
PEODME-LiClO4 3 mol kg -1
PEODME-LiClO4-Al2O3 kw. 3 mol kg -1
PEODME-LiClO4-Al2O3 oboj. 3 mol kg -1
1
0.1
0,1
10-6
10-5
10-4
10-3
10-2
c / mol kg
10-1
100
-1
101
0
20
40
60
o
temperatura/ C
PEGME-LiClO4
PEGME-LiClO4 -Al2O3neutral
PEGME-LiClO4 -Al2O3basidic
PEGME-LiClO4 -Al2O3acidic
…and temperature
80
100
Fuoss-Kraus
100
% of free ions in PEO-DME neutral system
as a function of temperature
80
100
% of ion pairs in PEO-DME neutral system
as a function of temperature
60
35
100
30
25
40
80
pairs
40
o
T/ C
ee ions
% of fr
60
20
20
1e-3
1e-2
C / mol *
1e-1
1e+0
% of ion
20
0 0%
20 % 1e-4
40 %
60 %
80 %
100 %
15
60
40
20
kg -1
35
0
30
T/
o
0
10-6
10-5
10-4
10-3
10-2
10-1
100
101
100
c / mol kg
-1
80
PEGME-LiClO4 -Al2O3 basidic
PEGME-LiClO4 -Al2O3 acidic
35
30
40
25
20
20
0 0%
20 % 1e-4
40 %
60 %
80 %
100 %
1e-3
1e-2
C / mol *
1e-1
kg -1
1e+0
T/ C
PEGME-LiClO4 -Al2O3 neutral
60
o
PEGME-LiClO4
15
25
C
% of ions triplets in PEO-DME neutral system
as a function of temperature
ts
ns triple
% of io
% par jonowych
80
1e+0
1e-1
20
0%
20 %
40 %
60 %
80 %
100 %
1e-2
-1
1e-3
15
1e-4
1e-5
C/
l*k
mo
g
Changes of the interface
resistance in time
PEO-based electrolytes transference number
Lithium transference numbers for (PEO)20LiClO4 based
composite electrolytes containing 10% by weight of inorganic
filler additives
Type of the
electrolyte
Type of the filler
Temperature/oC
Lithium transference
number
(PEO)20LiClO4
Filler free sample
40
0.31
(PEO)20LiClO4
Al2O3
40
0.61
(PEO)20LiClO4
Al2O3 (1% ASG)
40
0.66
(PEO)20LiClO4
Al2O3 (4% ASG)
40
0.72
(PEO)20LiClO4
Al2O3 (8% ASG)
40
0.77
(PEO)20LiBF4
0
70
0.32
(PEO)20LiBF4
Surface modified ZrO2
70
0.81
Supramolecular compounds
Calixarene 1
Calixarene 3
Calixarene 2
Calix[6]pyrrole
C72H96N4O6
C68H104N4O6
MW=1113.56 gr/mole
MW=1073.58 gr/mole
C72H94N6O10
MW=1203.55 gr/mole
C72H66N6
MW= 1014.52 gr/mole
Lithium transferrence numbers t+ for
LiI:PEO7 and LiI:PEO20
Polymer Type
Temp
(o C)
t+
LiI:PEO7
55
0.51
LiI:PEO7
75
0.56
LiI:PEO7
90
0.51
LiI:P(EO)7 (Calix.2) 0.3
75
0.74
LiI:P(EO)7 (Calix.2) 0.3
90
0.69
LiI:P(EO)7 (Calix.1) 0.3
75
0.35
LiI:P(EO)7 (Calix.1) 0.3
90
0.24
LiI:P(EO)7 (Calix.3) 0.3
75
0.70
LiI:P(EO)7 (Calix.3) 0.3
90
0.33
LiI:PEO20
55
0.35
LiI:P(EO)20 (Calix.2) 1
50
1
LiI:P(EO)20 (Calix.2) 1
75
0.93
LiI:P(EO)20 (Calix.2) 1
90
0.80
LiI:P(EO)20 (Calix.2) 0.3
50
0.51
LiI:P(EO)20 (Calix.1) 0.3
55
0.48
LiI:P(EO)20 (Calix.1) 1
55
0.45
LiI:P(EO)100
90
0.14
LiI:P(EO)100(Calix.1)0.25
90
0.15
LiI:P(EO)100(Calix.1)0.5
90
0.18
Experiment time - 60 minutes, applied voltage 0.01Volt.
Conductivity of the system
P(EO)10(LiI)1(Calixarene)x
t / °C
110 100 90
-3
10
-4
10
-5
10
-6
10
-7
10
-8
10
-9
total / Scm
-1
10
10
-10
10
-11
80
70
60
50
40
30
20
10
0
Calixarene 1
x=0
x = 0.1
x = 0.2
x = 0.4
x = 0.6
x = 0.8
2,6
2,8
3,0
3,2
-1
1000T / K
3,4
-1
3,6
3,8
Temperature dependence of the bulk
conductivity and interphase resistance RSEI of
the LiTf:P(EO)20 and LiTf:P(EO)20(C6P)0.5
Electrolytes
RSEI
Bulk conductivity
Lithium transference numbers for
PEO-LiX-Calix-6-pyrrole electrolytes
Molar fraction of
calix-6-pyrrole
Temperature/oC
Lithium
transference
number
(PEO)20LiI
0
70
0.25
(PEO)20LiI
0.125
70
0.56
(PEO)20LiI
0.25
70
0.75
(PEO)20LiI
0.5
70
0.78
(PEO)20LiBF4
0
70
0.32
(PEO)20LiBF4
0.125
70
0.78
(PEO)20LiBF4
0.25
70
0.81
(PEO)20LiBF4
0.5
70
0.85
(PEO)20LiCF3SO3
0
75
0.45
(PEO)20LiCF3SO3
0.5
70
0.76
Type of the
electrolyte
Self-diffusion coefficients D
and t+ at 363 K
D-
D+
10-8 cm2/s
10-8 cm2/s
10-8 cm2/s
6.51
3.37
27.5
36.1
24.6
20.0
Dpolymer
PEO-LiBF4-calixpyrrole
PEO-LiBF4
t+
0.47
0.36
How does it (probably) work?
KI>Kcal>KT
KI>KT>Kcal
Kcal>KI>KT
KI-ion pairs formation constant
KT-ionic tiplets formation
Kcal-calix-anion complex constant
O
O
O
O
O
ClO4
Calix
-
Li+
ClO4-
ClO4-
Calix
Li+
O
Calix
Li+
Ion pairs (KA) and Ionic Triplets (KT) formation
constans calculated for PEO-LiX (X=I-, CF3SO3-)
electrolytes
KA
KT
Salt
LiI
3,87x104
130
LiCF3SO3
LiBF4
3,18x104
1.75x105
72
77.69
Kcal6-anion=27x103
PEO-based electrolytes additives stability
Cyclic voltammograms of LiTf:PEO20 membranes with and without
C6P and SiO2 additives at (a)75˚C and (b)90˚C over potential range
of 0-5.0V using SS/PE/SS cell configuration
H. Mazor, D. Golodnitsky, E. Peled, W. Wieczorek, B. Scrosati, J.Power Sources, 178 (2008) 736743
New Types of Ceramic Composites
1/2 – Concept and Structure
Inhibition of
crystallization
New Types of Ceramic Composites
2/2 – Preliminary/First!!!
Electrochemical Testing
Anions:
•
Control dissociation and conductivity
•
Control transport numbers t+ /t-
•
•
are an important part of SEI build-up
at +/- electrodes
Control aluminium corrosion
Classics…
BF4-
ClO4-
Explosive !
Toxic !
PF6-
AsF6-
SbF6-
Tendency to decompose according to equilibrium:
LiBF4  BF3 + <LiF>
LiPF6   PF5 + <LiF>
Fast reaction above 80°C
 Destruction of electrolyte and interfaces
Conceptual approach to anion design

“O” is not a favorable building block:
Strong Li—O interactions  ion pairing, ≠ ClO4-, BOBIf O present, F or CnF2n+1 is required

“N, C” are favorable:
Weak interactions Li—N but easy oxidation
Stability Domains
Fluorinated anions
LiCoPO4
LiMO2
mixed
oxides
LiMnPO4
Non fluorinated anions
LiFePO4
LiV3O8
Li4Ti5PO12
Graphite
Li metal
Diagonally Opposed Interests?
Organic chemistry
Enhance the activity of anions (SN)
+
+
Electrochemistry
Maximize the conductivity
-
-
Ionic processes
-
-
I- = 2,2 Å
Li+
 design of
polyatomic
anions
Hückel anions…
Aromaticity 4n + 2 «  » electrons
X = N, C-CN, CRF, S(O)RF
pKA = 10-60
pKA = 10-20
Gain of > 1 eV by resonance
See P. Johansson et al
Physical Chemistry Chemical Physics, volume 6, issue 5, (2004).
LiDCTA
NC
CN
NC
H2N
NH2
-2H2O
-
O
O
N-
N
N
N
NC
CN
CN
DCTA
N
-
Stable to 3.8 V (La Sapienza, KZ)
inexpensive
N
N
NC
CN
Gives quite fluid ILs
N
N
N
N
-
Most Stable Lithium Imidazole Configurations
1.93 Å
1.88 Å
1.87 Å
1.92 Å
LiTDI
LiPDI
B3LYP/6-311+G(d)
Scheers et al. 2009
Gas Phase Ion Pair Dissociation Energies
Li+ (g) + Anion- (g)
Ion pair (g)
LiTDI
<
LiPDI
<
LiDCTA
<
LiTFSI
<
LiPF6
MP2/6-31G(d)
LiTDI
LiPDI
LiDCTA
LiTFSI
LiPF6
Scheers et al. 2009
LiTDI (2-trifluoromethyl-4,5dicyanoimidazole lithium salt)
O
N
C
NH2
+
C
N
N
C
CF 3
O
C
NH2
O
C
dioxane / T
C
+ Li2CO3 / water
C
N
C
CF 3
C
N
-
N+
Li
- Easy, low-demanding, inexpensive, one-step, high yield
syntheses;
- Salts are pure, stable in air atmosphere, non-hygroscopic,
stable up to 250°C, easy to handle;
CF 3
New salts
N
NN
N
-
N
CF3
NN
N
Li
-
N
+
C 2 F5
LiTDI
N
Li
+
N
LiTPI
N
n-C3F7
LiHDI
N Li
CF3
N
-
+
LiPDI
N
N
Li
+
Conductivity in PEO
SS / PEO20LiX / SS
0.01
1E-3
1E-4
-1
conductivity /  cm
-1
cooling scan
1E-5
1E-6
DCTA
LiDCTA
PDI
LiPDI
LiTDI
TDI
1E-7
1E-8
2.5
2.6
2.7
2.8
2.9
3.0
3.1
1000/T / K
-1
3.2
3.3
3.4
3.5
T (°C)
127 111
0.01
10
-2
10
-3
10
-4
10
-5
10
-6
10
-7
97
84
72
60
49
39
30
21
13
P(EO)20LiCF3SO3
(Scm )
1E-4
1E-5
PEO
A
PEO2020LiTDI
PEO
LiPDI
PEO 20 B
20
1E-6
2.6
2.8
3.0
1000 / T
N
0.01
2,5
2,6
2,8
2,9
3,0
3,1
3,2
3,3
3,4
3,5
-1
1000/T (K )
PEO20LiBOB/ LiBF4
Hot-Pressing
T / °C
111,5 84 60,1 39,4 21
2,7
0.01
PEO20LiCF3SO3+ ZrO2SA
Casting
T / °C
111,5 84 60,1 39,4 21
T/°C
111,5 84 60,1 39,4 21
0.01
-1
N
+
Li
3.2
-1
PEO20LiDCTA
Hot-Pressing
CN
Conducibilità / Scm
1E-4
1E-5
1E-4
PEO20 LiDCTA
1E-5
PEO20 LiBF4
1E-8
2.4 2.6 2.8 3.0 3.2 3.4 3.6
-1
-1
1000T / K
1E-7
1E-3
1E-4
1E-5
1E-6
1E-6
1E-7
1E-3
-1
-1
1E-3
Conducibilità / Scm
N
K
Conducibilità / Scm
NC
P(EO)20LiDCTA
-1
Conductivity
PEO20LiTDI
PEO20LiPDI
Hot-Pressing
S / cm
1E-3
1E-6
PEO20 LiBOB
PEO20 LiBF4
1E-8
2.4 2.6 2.8 3.0 3.2 3.4 3.6
-1
-1
1000T / K
1E-7
x: 0%
x: 10%
1E-8
2.4 2.6 2.8 3.0 3.2 3.4 3.6
-1
-1
1000T / K
Anodic
stability
Li / PEO LiX / Super P
20
current / mA/cm
2
0.20
DCTA
LiDCTA
PDI
LiPDI
TDI
LiTDI
Anodic breakdown
voltage vs. Li
0.15
0.10
0.05
0.00
3.0
3.5
4.0
4.5
5.0
Potential / V
5.5
6.0
6.5
P(EO)20LiDCTA
3.6V
P(EO)20LiPDI
4.0V
P(EO)20LiTDI
4.0V
Interphase resistance - PEO
Li / PEO20LiX / Li
-60
2h
7h
2d
7d
-100
-40
-20
-80
4.5h
1d
5d
12d
-60
-40
-20
0
0
0
40
80
120
160
200
0
40
80
Zreal / Ohm
2h
7h
2d
7d
-80
-60
LiPDI
4.5h
1d
5d
12d
-40
-20
0
0
120
Zreal / Ohm
-100
Zimm / Ohm
Zimm / Ohm
-80
4.5h
1d
5d
12d
Zimm / Ohm
2h
7h
2d
7d
LiTDI
LiDCTA
-100
40
80
120
Zreal / Ohm
160
200
160
200
Interphase resistance - PEO
Li / PEO20LiX / Li
PDIa
LiPDIa
PDIb
LiPDIb
LiTDIa
TDIa
LiTDIb
TDIb
LiDCTAa
DCTAa
LiDCTAb
DCTAb
240
resistance / Ohm
200
160
120
80
40
0
0
3
6
time / d
9
12
15
Cycling behaviour
% of capacity at C/20
Rate capability (PEO)
% of capacity at C/20
Rate capability (PEO)
Research team working on new salts
Presentation of research team
working on new lithium salts:
Warsaw University of Technology:
- L. Niedzicki, J. Syzdek and W. Wieczorek – characterization of salts and low
molecular weight polyether electrolytes
- J. Prejzner, P. Szczeciński, M. Bukowska - synthesis of new salts
- A. Błażejczyk, M. Kalita – synthesis of anion receptors
- Z. Żukowska M. Marcinek – spectroscopic studies
Universite de Picardie Jules Verne, Laboratoire de Reactivite et de Chimie des Solides
- S. Grugeon, S. Laruelle - characterization of solid polymeric electrolytes, studies of
electrochemical stability and battery performance
- and M. Armand – development of new salt systems
Faculty of Chemistry, University of Rome, “ La Sapienza
- S. Panero, P. Reale and B. Scrosati, - characterization of solid polymeric
electrolytes; conductivity, transference numbers and electrochemical stability
Department of Applied Physics, Chalmers University of Technology,
- J. Scheers, P. Johansson, P. Jacobsson – modeling and spectroscopic studies