yunasko aabc 2013
TRANSCRIPT
Y. Maletin, N. Stryzhakova, S. Zelinskiy,
S. Chernukhin, D. Tretyakov, S. Tychina
How Electrochemical Science
Can Improve the EDLC Performance
AABC Europe 2013, Strasbourg, June 24-28
2
How Electrochemical Science
Can Improve the EDLC Performance
3
How Electrochemical Science
Can Improve the EDLC Performance
4
How Electrochemical Science
Can Improve the EDLC Performance
5
How Electrochemical Science
Can Improve the EDLC Performance
• 0V corresponds to the equilibrium potential
• scan rate: 10 mV/s
NOTE: potential range
with Faraday processes
cannot be used for long
6
How Electrochemical Science
Can Improve the EDLC Performance
2.43.1
How Electrochemical Science
Can Improve the EDLC Performance
7
8
How Electrochemical Science
Can Improve the EDLC Performance
-10
0
10
20
30
40
50
60
70
40 50 60 70 80 90 100 110 120
DC=2.7V AC= 5mV Freq --> 0.1Hz to 10 kHz
1- poor
2- typical
3- optimized
SC design:
1
2
3
23
How Electrochemical Science
Can Improve the EDLC Performance
1
9
10
100
101
102
103
104
0.6
0.7
0.8
0.9
1.0
frequency, Hz
R, O
hm
. cm
2
-10
-5
0
5
10
15
C, F
/cc
How Electrochemical Science
Can Improve the EDLC Performance
rAl-C ≤ 0.01 (in Yunasko technology)
rC ~ 0.05
Thus: rEl ~ 0.75
“pore resistance” ~ 0.6
SC resistivity (in W.cm2)
total ~ 0.8
Though: rEl-in-bulk ~ 0.15 (electrode+separator thickness)
11
How Electrochemical Science
Can Improve the EDLC Performance
12
Slit-shaped pores or
just shear cracks of
graphene layers
How Electrochemical Science
Can Improve the EDLC Performance
13
• 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.
How Electrochemical Science
Can Improve the EDLC Performance
14
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 )
NOTE: in bulk solution
Deff = 10.1×10-10 m2/s
How Electrochemical Science
Can Improve the EDLC Performance
15
Capacitance,
F
Internal resistance,
mΩ
Time constant,
s
Spec. energy (CU
2/2),
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
Hybrid cells (2.8 V)
6000a 1.0 6.0 37 4.5 NA
Module (16 V)
200c,d
0.7 0.14 2.8 3.6 34
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).
How Electrochemical Science
Can Improve the EDLC Performance
16
How Electrochemical Science
Can Improve the EDLC Performance
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
17Continuous cycling the module over 8 hours
basic city duty cycle
ΔT:cells in the centre
cells at the edge
How Electrochemical Science
Can Improve the EDLC Performance
Time, s
V
A, charge
A, discharge
18
1000 100000
5
10
15
20
25
30
35
40
Sp
ec
ific
en
erg
y,
Wh
/kg
Specific power, W/kg
Hybrid 2.7-1.35 V
Hybrid 2.7-2.0 V
Supercapacitor 650F 2.7-1.35 V
How Electrochemical Science
Can Improve the EDLC Performance
As tested in ITS,
UC Davis, CA
19
How Electrochemical Science
Can Improve the EDLC Performance
20
-40 -20 0 20 40 600
20
40
60
80
100
50 0C25
0C
Dis
ch
arg
e c
ap
acit
y, %
t, 0C
1 C
20 C
50 C
-30 0C
How Electrochemical Science
Can Improve the EDLC Performance
21
How Electrochemical Science
Can Improve the EDLC Performance
22
How Electrochemical Science
Can Improve the EDLC Performance
23
How Electrochemical Science
Can Improve the EDLC Performance
24
How Electrochemical Science
Can Improve the EDLC Performance
25