Transcript Market Opportunity

How Electrochemical Science
Can Improve the EDLC Performance
Y. Maletin, N. Stryzhakova, S. Zelinskiy,
S. Chernukhin, D. Tretyakov, S. Tychina
AABC Europe 2013, Strasbourg, June 24-28
How Electrochemical Science
Can Improve the EDLC Performance
Presentation outline
1. Yunasko key targets
2. CV and galvanostatic measurements
3. Impedance measurements (EIS)
4. In-pore diffusion measurements
5. Recent test results: unit cells and modules
6. Company development
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How Electrochemical Science
Can Improve the EDLC Performance
Why SC’s sometimes look like the Cinderella
of energy storage market?
1. Billions were invested in Li-ion batteries over the last few
decades resulting in a huge advance of this technology.
2. SC technology was developing rather slowly and was
deemed to be rather complicated and expensive for many
applications.
Hence, Yunasko approach:
1. SC’s must demonstrate by far the best performance in
areas where they can compete with batteries or
complement them.
2. Low cost and commercially available components should
preferably be used.
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How Electrochemical Science
Can Improve the EDLC Performance
Cell design for 3-electrode measurements
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How Electrochemical Science
Can Improve the EDLC Performance
CV: scanning the electrode potential to (+)
NOTE: potential range
with Faraday processes
cannot be used for long
• 0V corresponds to the equilibrium potential
• scan rate: 10 mV/s
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How Electrochemical Science
Can Improve the EDLC Performance
CV curves: A - 3-electrode cell
B - SC prototype
A
B
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How Electrochemical Science
Can Improve the EDLC Performance
Charge accumulated in (-) or (+) potential range
2.4
3.1
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How Electrochemical Science
Can Improve the EDLC Performance
Hybrid cell: CC charge-discharge curves
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How Electrochemical Science
Can Improve the EDLC Performance
Impedance spectroscopy (Nyquist plots)
DC=2.7V
AC= 5mV
Freq --> 0.1Hz to 10 kHz
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70
2
SC design:
60
50
1
40
30
20
10
1- poor
3
2
2- typical
1
3- optimized
0
-10
40 50 60 70 80 90 100 110 120
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How Electrochemical Science
Can Improve the EDLC Performance
Impedance spectroscopy
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1.0
C, F/cc
R, Ohm.cm2
(capacitance and resistance vs. frequency)
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0.9
5
0.8
0
0.7
-5
0.6
-10
0
10
1
10
2
10
3
10
4
10
frequency, Hz
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How Electrochemical Science
Can Improve the EDLC Performance
Yunasko approach to reduce R and RC
SC resistivity (in W.cm2)
Thus:
total
~ 0.8
rAl-C
≤ 0.01 (in Yunasko technology)
rC
~ 0.05
rEl
~ 0.75
Though: rEl-in-bulk
“pore resistance”
~ 0.15 (electrode+separator thickness)
~ 0.6
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How Electrochemical Science
Can Improve the EDLC Performance
TEM image of carbon powder
Slit-shaped pores or
just shear cracks of
graphene layers
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How Electrochemical Science
Can Improve the EDLC Performance
Why the in-pore electrolyte mobility is slow?
• Pore width is mostly within 1 ÷ 3 nm (is comparable
with the Debye length).
• There is no potential gradient in narrow pores, and
therefore, diffusion is the only driving force for ions
to move. (Y.Maletin et al., 7th EDLC Seminar, FL, Dec.1997)
• Diffusion can be slow due to strong interaction
between the charged electrolyte species and
conductive pore walls.
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How Electrochemical Science
Can Improve the EDLC Performance
Correlation of in-pore diffusion coefficients
with EDLC resistance
NOTE: in bulk solution
Deff = 10.1×10-10 m2/s
Diffusion coefficients of Fc+ cations in various NP carbons
(Rotating Disc Electrode measurements, see: A.J.Bard, L.R.Faulkner; Electrochemical
Methods. Fundamentals and Applications (2nd ed.); Wiley, 2001, p.335 )
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How Electrochemical Science
Can Improve the EDLC Performance
Test results
Capacitance,
Internal
resistance,
Time
constant,
F
mΩ
s
Spec.
energy
2
(CU /2),
W.h/kg
Spec.
power
(95% eff.),
kW/kg
Max.
spec.
power,
kW/kg
EDLC power cells (2.7V)
480a
0.20
0.10
4.9
10.2
91
1200a,b
0.10
0.12
5.3
8.9
79
1500b
0.09
0.14
6.1
9.1
81
4.5
NA
3.6
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Hybrid cells (2.8 V)
6000
a
1.0
6.0
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Module (16 V)
200c,d
0.7
0.14
2.8
a)
Also tested in ITS, UC Davis, CA; b) Also tested in JME, Cleveland, OH;
c) Also tested in Wayne State University, Detroit, MI;
d) Equipped with a proprietary voltage balancing system (patent pending).
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How Electrochemical Science
Can Improve the EDLC Performance
Recent Yunasko EDLC modules
15 V, 200 F:
max working voltage 16.2 V
max surge voltage 18.0 V
dc pulse resistance 0.5 mΩ
mass 2.5 kg
equipped with a proprietary
voltage balancing system
and temperature sensor
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How Electrochemical Science
Can Improve the EDLC Performance
Yunasko competitive advantage:
low heat generation
basic city duty cycle
V
ΔT:
cells in the centre
A, charge
cells at the edge
A, discharge
Time, s
Continuous cycling the module over 8 hours
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How Electrochemical Science
Can Improve the EDLC Performance
Ragone plot: EDLC vs hybrid devices
Hybrid 2.7-1.35 V
Hybrid 2.7-2.0 V
Supercapacitor 650F 2.7-1.35 V
Specific energy, Wh/kg
40
35
30
As tested in ITS,
UC Davis, CA
25
20
15
10
5
0
1000
10000
Specific power, W/kg
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How Electrochemical Science
Can Improve the EDLC Performance
Hybrid cell: cycle life
(charge/discharge between 2.7 and 1.35 V)
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How Electrochemical Science
Can Improve the EDLC Performance
Hybrid cell: temperature/rate performance
-30 0C
1C
20 C
50 C
100
Discharge capacity, %
50 0C
25 0C
80
60
40
20
0
-40
-20
20
0
t, 0C
40
60
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How Electrochemical Science
Can Improve the EDLC Performance
Company background and prospects
Principal researchers participate in various supercapacitor
projects since 1989
YUNASKO Ltd: registered in the UK since 2010
Subsidiaries:
YUNASKO-Ukraine: R&D, design bureau and pilot plant since
2010
YUNASKO-Latvia: industrial scale production will start in 2014
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How Electrochemical Science
Can Improve the EDLC Performance
R&D team: breakthrough story
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How Electrochemical Science
Can Improve the EDLC Performance
Conclusions
1. Electrochemical methods are a powerful instrument to
show a way to SC improvements.
2. Yunasko technology* enables to significantly reduce
SC resistance and to achieve the power density up to
100 kW/kg.
3. Yunasko hybrid devices* demonstrate by far larger
energy and power density than competing hybrids.
4. First industrial scale production will soon be
launched.
5. Yunasko is open to cooperation with investors and
industrial partners.
* US and EU patents pending
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How Electrochemical Science
Can Improve the EDLC Performance
Acknowledgements
Many thanks to Dr. Andrew Burke (ITS) and Prof. John R. Miller (JME)
for stimulating discussions and valuable help in testing
Special thanks to Dekarta Capital Fund
for investing in the Yunasko project
Participation in EU FP7 Energy Caps project
is very much acknowledged
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THANKS FOR YOUR ATTENTION!
Please visit us at: www.yunasko.com
E-mail:
[email protected]
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