Post on 13-Mar-2020
Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW) Baden-Württemberg
AABC 2017, 30 January -2 February 2017 Mainz, Germany
S. Dsoke, M. Secchiaroli, E. Gucciardi, H. Y. Tran, B. Fuchs, S. Calcaterra,
M. Wohlfahrt-Mehrens
Materials selection for asymmetric/hybrid supercapacitors
Modulation of energy and power Asymmetric or (hybrid) supercapacitors
Ion adsorptionLi insertion
--
-
-
--
- -
Li+
metal oxidecarbon
+-
--
-
-
--
- -
--
-
-
--
- -
Li+Li+
metal oxidecarbon
+-
Li insertionmaterial
Ion adsorptionLi insertion
--
-
-
--
- -
Li+
metal oxidecarbon
+-
--
-
-
--
- -
--
-
-
--
- -
Li+Li+
metal oxidecarbon
+-
Li insertionmaterial
--
-
-
--
- -
Li+
metal oxidecarbon
+-
--
-
-
--
- -
--
-
-
--
- -
Li+Li+
metal oxidecarbon
+-
Li insertionmaterial
Hybridization at cell level Hybridization at electrode level
- 1 -
Behavior of carbonaceous materials in battery-like electrolytes
Cell Balancing (mass ratio, thicknesses, cell
voltage)
Electrode formulation with environmental friendly and cheaper
binders as an alternative to PVDF
Electrode processing optimization (composition, thickness, compaction,
adhesion)
current collector
Activated Carbon Electrode
LTOElectrode
Separatorcurrent collector
20 µm 245 µm
20 µm 85 µm
20 µm 40 µm
AC/LTO = 4.17
AC/LTO = 1.54
AC/LTO = 0.72Key aspects
Carbon Carbon
+ -
+
+
+
+
+
+ --
-
-
--
- -
PF6-
Li+
+
Electrochemical Stability Window
Cycling stability Rate capability Electrochemical Impedance
Spectroscopy
Materials and combinations
Li4Ti5O12 (LTO) Li3V2-δNiδ(PO4)3 (LVNP) (δ =0, 0.05, 0.1)
poresActivated Carbon (AC)
- 2 -
Classical hybridization combining lithium insertion and DLC electrode
- 3 -
Li-ion capacitor based on Graphite and Activated Carbon
Li-ion capacitor based on LTO and Activated Carbon
Cericola et al. Journal of Power Sources 196 (2011) 10305-10313
“The LTO//AC hybrid do neither improve the battery nor the capacitor, because the specific energy is typically limited by the capacitor (AC) electrode and the specific power by the battery
(LTO) electrode.“
K. Naoi, S. Ishimoto, J-ichi Miyamoto and W. Naoi, Energy Environ. Sci, 5 (2012) 9363
How to balance a capacitor-type electrode with a battery-type electrode?
Classical balancing
Mass balancing between AC and LTO has to be made to
fully use both electrodes
The mass balancing is normally made based on the capacities obtained
at low C-rates
- 4 -
The mass balancing is not anymore valid at high currents!
0 50 100 150 200 250 300 350 400 450 500
1.2
1.5
1.8
2.1
2.4
2.7
3.0
3.3
3.6
3.9
4.2
4.5
0 10 20 30 40 50 60 70 80 90 100 110 120 130
0.9
1.2
1.5
1.8
2.1
2.4
2.7
3.0
3.3
3.6
3.9
4.2
4.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 140.30.60.91.21.51.82.12.42.73.03.33.63.94.24.5
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
AC/LTO 4.17 AC/LTO 1.54 AC/LTO 0.72
E / V
vs. L
i/Li+
time / s
cycle at 10 C
E / V
vs. L
i/Li+
time / s
cycle at 25 C
E / V
vs. L
i/Li+
time / s
cycle at 100 C
E / V
vs. L
i/Li+
time / s
cycle at 200 C
Our approach: modulation of AC/LTO mass ratio Effect of the AC/LTO mass ratio at high C-rate
20 µm 245 µm
AC/LTO = 4.17
20 µm 85 µm
AC/LTO = 1.54
20 µm 40 µm
AC/LTO = 0.72
S. Dsoke, B. Fuchs, E. Gucciardi and M. Wohlfahrt-Mehrens, J. of Power Sources, 282 (2015) 385-393 - 5 -
Classical balancing
100 1000 10000
1
10
100
AC//AC AC//LTO (ratio: 4.17) AC//LTO (ratio: 1.54) AC//LTO (ratio: 0.72)
Energ
y Den
sity /
Wh L
-1
Power Density / W L-1
1h10 min 60 sec
5 sec
1.5 sec
Energy-Power relationship Effect of the AC/LTO mass ratio
40 µm 40 µm
AC/AC = 1 Symmetric EDLC
20 µm 245 µm
AC/LTO = 4.17
20 µm 85 µm
AC/LTO = 1.54
20 µm 40 µm
AC/LTO = 0.72
S. Dsoke, B. Fuchs, E. Gucciardi and M. Wohlfahrt-Mehrens, J. of Power Sources, 282 (2015) 385-393 - 6 -
Decreasing the mass ratio AC/LTO leads to better high power performances • Smaller thickness of the AC cathode lower diffusion resistance • Intercalation degree of LTO anode influences the RCT • Improve the performance of an asymmetric device by simply optimizing the mass
ratios between cathode and anode.
0.335 Ω 0.436 Ω 1.23 Ω < < Charge transfer resistance
20 µm 40 µm
AC/LTO = 0.72
20 µm 85 µm
AC/LTO = 1.54
20 µm 245 µm
AC/LTO = 4.17[1] W. Lu et al. J. Electrochem. Soc. 154 (2007) A114-A118
Increase of RCT with intercalation degree in LTO electrodes also
observed by Lu et al. [1]
Effect of the AC/LTO mass ratio
COMPOSITE ANODECOMPOSITE CATHODE
Asymmetric-Hybrid Battery Supercapacitor
+ -
COMPOSITE ANODECOMPOSITE CATHODE
Asymmetric-Hybrid Battery Supercapacitor
+ -
COMPOSITE ANODECOMPOSITE CATHODE
Asymmetric-Hybrid Battery Supercapacitor
+ -
COMPOSITE ANODECOMPOSITE CATHODE
Asymmetric-Hybrid Battery Supercapacitor
+ -
Containing Li-salt, necessary for the intercalation/deintercalation processes High ionic conductivity (low resistance), to enable high power
Stable in a broad voltage range where the materials are electrochemically active
Compatible with the electrode material used (activated carbon and Li-insertion materials)
Selection of electrolyte for asymmetric supercapacitor
Commercial (organic) electrolytes employed in EDLCs and LiBs
Salt: NEt4BF4
Solvent: ACN, PC
Salt: LiPF6, LiBF4, LiClO4
Solvents: mixture of alkil carbonates (EC, DMC, DEC…)
Examples: 1M NEt4BF4 in ACN
or 1M NEt4BF4 in PC
Examples: LiPF6 in EC:DMC (1:1)
or 1M LiPF6 in EC:DMC (7:1) various combinations
using a systematic approach - 9 -
(1): change of solvent (AN EC:DMC) factor of x3
(2): change of cation (NEt4+ Li+ in EC:DMC) factor of x3.3
(Li+ is strongly solvated, TEA+ is not)
(3): change of anion (BF4- PF6
- in EC:DMC) factor of ÷2
(4): difference between NEt4BF4 and LiPF6
(common salts for EDLC or LIB) "only" factor of ÷1.5
Electrochemical impedance response of symmetric AC//AC cells with various electrolyte combinations
Experimental setup: Symmetric Swagelock® cell 2 identical Activated Carbon electrodes (1.131cm2) 3 Separator (GFA) Activated Carbon: HDLC-20BST-UW from HayCarb
1M LiPF6 in EC:DMC (1:1) starting point for further investigations
T. Zhang, B. Fuchs, M. Secchiaroli, M. Wohlfahrt-Mehrens, S. Dsoke, Electrochimica Acta, 218 (2016) 163-173
0.8M LiPF6 + 0.2M Et4NBF4 in EC:DMC (1:1, wt.%)
0.8M LiPF6+ 0.2M Et4NBF4 in PC
1M LiPF6 in EC:DMC (1:1, w.t.%)
1M LiPF6 in PC
Li4Ti5O12 LiFePO4 Li3V2-xNix(PO4)3
ΔV: 2.8 V
Electrochemical stability window - compatibility AC-electrolyte -
T. Zhang, B. Fuchs, M. Secchiaroli, M. Wohlfahrt-Mehrens, S. Dsoke, Electrochimica Acta, 218 (2016) 163-173
0 10 20 30 40 50 60 70 80 90 1001.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 10 20 30 40 50 60 70 80 90 1001.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 10 20 30 40 50 60 70 80 90 1001.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 10 20 30 40 50 60 70 80 90 1001.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
E / V
vs. L
i/Li+
time/s
cycle 5 cycle 1000 cycle 8000 cycle 15000 cycle 20000
E / V
vs. L
i/Li+
time/s
cycle 5 cycle 1000 cycle 8000 cycle 15000 cycle 20000
E / V
vs. L
i/Li+
time/s
cycle 5 cycle 1000 cycle 8000 cycle 15000 cycle 20000
E / V
vs. L
i/Li+
time/s
cycle 5 cycle 1000 cycle 8000 cycle 15000 cycle 20000
Voltage profile evolution with cycling
ESW
ESW
LiPF6+NEt4BF4 in PC LiPF6 in PC
LiPF6+NEt4BF4 in EC-DMC LiPF6 in EC-DMC
T. Zhang, B. Fuchs, M. Secchiaroli, M. Wohlfahrt-Mehrens, S. Dsoke, Electrochimica Acta, 218 (2016) 163-173
Selection of electrolytes (interaction AC-electrolyte)
Electrolyte – AC interactions
Resistance
0 5 10 15 20 25 30 35 40 45 500
5
10
15
20
25
30
35
40
45
50
-Im(Z
)/Ohm
Re(Z)/Ohm
PC>EC-DMC
Cycling stability
0 2000 4000 6000 8000 10000 12000 14000 16000 18000 2000002468
1012141618202224262830
Disc
harg
e cell
capa
citan
ce / F
g-1
cycle number
LiPF6 in EC-DMC LiPF6 + Et4NBF4 in EC-DMC LiPF6 in PC LiPF6 + Et4NBF4 in PC
superior stability of LiPF6 in PC
decomposition products at the PE induce degradation at the NE
modification of positive electrode surface (e.g. reducing the functional groups) may increase the stability and reduce the negative electrode aging
ESW 0.8M LiPF6 + 0.2M Et4NBF4
in EC:DMC (1:1, wt.%)
0.8M LiPF6+ 0.2M Et4NBF4 in PC
1M LiPF6 in EC:DMC (1:1, w.t.%)
1M LiPF6 in PC
LiPF6 in EC-DMC
LiPF6 Et4NBF4 in EC-DMC
LiPF6 Et4NBF4 in PC
LiPF6 in PC
T. Zhang, B. Fuchs, M. Secchiaroli, M. Wohlfahrt-Mehrens, S. Dsoke, Electrochimica Acta, 218 (2016) 163-173
Novel green tri-material negative electrode for high energy and power Lithium-ion supercapacitors
* M. Secchiaroli, G. Giuli, B. Fuchs, R. Marassi, M. Wohlfahrt-Mehrens, S. Dsoke, J. of Material Chemistry A, 3, (2015) 11807
Composition selection
Composition 1 Composition 2 Composition 3 Composition 40
10
20
30
40
50
60
70
80
% Active material
LTO
AC
AC
AC
AC
LTO
LTO
LTO
LVNP
/C
LVNP
/C
LVNP
/C
Acti
vated
mate
rials
% w
(comp
uted o
n a.m
. con
tent)
LVNP
/C0 20 40 60 80 100 120
0
20
40
60
80
100
120 LVNP/C:LTO:AC = 24:51:24 LVNP/C:LTO:AC = 51:24:24 LVNP/C:LTO:AC = 24:24:51 LVNP/C:LTO:AC = 33:33:33
0.16 0.32 0.8 1.6 3.2 6.4 9.6 16 24 32 0.32 0.16 A g-1
Spec
ific C
apac
ity / m
Ah g-1
Cycle number
Capacitor-type protocol
0 20 40 60 80 100 1200
20
40
60
80
100
120
0.16 0.32 0.8 1.6 3.2 6.4 9.6 16 24 32 0.32 0.16 A g-1
Spec
ific Li
de-in
s cap
acity
/ mAh
g-1
LVNP/C:LTO:AC = 24:51:24 LVNP/C:LTO:AC = 51:24:24 LVNP/C:LTO:AC = 24:24:51 LVNP/C:LTO:AC = 33:33:33
Cycle number
Battery-type protocol
0 20 40 60 80 100 1200
20
40
60
80
100
120
0.16 0.32 0.8 1.6 3.2 6.4 9.6 16 24 32 0.32 0.16 A g-1
LVNP/C:LTO:AC = 24:51:24 LVNP/C:LTO:AC = 51:24:24 LVNP/C:LTO:AC = 24:24:51 LVNP/C:LTO:AC = 33:33:33
Spec
ific C
apac
ity / m
Ah g-1
Cycle number
Hybrid-protocol
selected
compositions
10 wt%Binder Na-alginate Electrolyte: 1M LiPF6 in EC:DMC (1:1) - 15 -
Evaluation of full-asymmetric-hybrid systems
0.0 0.5 1.0 1.5 2.0 2.5
1.5
2.0
2.5
3.0
3.5
4.0
4.5
E / V
vs. L
i+ /Li
Time / h
Positive electrode Negative electrode
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Cell
Cell voltage / V
0.0 0.5 1.0 1.5 2.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
E / V
vs. L
i+ /Li
Time / h
Positive electrode Negative electrode
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Cell
Cell voltage / V
charge/discharge at 0.05 A g-1
double layer region
double layer region
selected tri-material
- 16 -
0.1 1 101
10
100
Spec
ific E
nerg
y / W
h kg-1
Specific Power / kW kg-1
Hybrid A Hybrid B LVNP II AC [1] AC II AC
1 h
6 min
1 min
14.4 s
3.6 s
0.01 0.1 1
10
100
Ener
gy D
ensit
y / W
h L-1
Power Density / kW L-1
Hybrid A Hybrid B LVNP II AC AC II AC
Evaluation of full-asymmetric-hybrid systems Ragone plots
Improved energy and power
- 17 -
[1] M. Secchiaroli, G. Giuli, B. Fuchs, R. Marassi, M. Wohlfahrt-Mehrens, S. Dsoke, J. of Material Chemistry A, 3, (2015) 11807-11816 M Secchiaroli, R Marassi, M Wohlfahrt-Mehrens, S Dsoke, Electrochimica Acta 219, (2016) 425-434
„New electrode design concept for hybrid battery supercapacitors“ (Novacap)
Acknowledgement
Emanuele Gucciardi Sonia Dsoke (Group Leader) Silvia Calcaterra Marco Secchiaroli Hai Yen Tran Kerstin Fischinger
Roberto Marassi
Financial support from German Federal Ministry of Education and Research (BMBF)
under the grant 03EK3021
- 18 -
Bettina Fuchs, Tong Zhang, Ann-Kathrin Huwer, Carmen Mäuser, Agnese Birrozzi Xu Tian