Presented in 16th International Seminar on Double Layer Capacitors
& Hybrid Energy Storage Devices
December 4 - 6, 2006
Latest developments in
Carbide Derived Carbon
for energy storage applications
M. Lätt*, J. Leis, M. Arulepp, H. Kuura, E. Lust
Tartu Technologies Ltd., 185 Riia St., 51014 Tartu, Estonia
University of Tartu, 2 Jakobi St., 51014 Tartu, Estonia
www.skeletonnanolab.com
Carbide-Derived Carbon (CDC)
• CDC is made by chemically extracting the metal or
metalloid from carbide crystal lattice
MxC+ xy/2 Cl2
___
> xMCly + C
• Carbon particles retain the shape and size of precursor
carbide. The structure and porosity of carbon is
significantly influenced by the structure and chemical
composition of carbide.
Pore structure characteristics of
different CDC materials
Carbide
• TiC
• TiC/TiO2
• SiC
• NbC
• ZrC
• Mo2C
• B4C
• Al4C3
SBET [m2g-1]
1100 - 1500
1300 - 1800
800 - 1400
1200 - 2000
1500 - 2000
1200 - 2200
800 - 1800
1100 - 1400
Peak pore size [Å]
7-9
8 - 13
7-8
8-10
8-10
8 - 40
9 - 20
8 - 20
Pore size distribution of different
CDC materials
350
C(SiC)
C'(TiC)
C(Al4C3)
B4C
C(Mo2C)
Incremental Pore Area / m g
2 -1
300
250
200
150
100
50
0
1
10
Pore Width / Angstrom
100
Possible applications for CDC
• ADSORPTION
•
•
•
•
H2, CH4, NH3 etc. LMW gas storage
Separation of toxic components from mixtures
Purification of inert gas
Water desalination
• ELECTRONICS
•
•
Electron field emission (e.g. flat panel displays)
Semiconductors
• ENERGY STORAGE
•
•
•
Batteries
Fuel cells
Supercapacitors
H2 storage
Carbide Derived Carbon
can store over 4 %wt. of
Hydrogen @ 6 atm. & 77K
(ρC ~ 0.72 g/cm3)
•
Energy density
•
•
•
•
Gasoline
Propane
Ethanol
Liq H2
Wh/Kg
9000
6600
6100
2600
Stored H2 1100
•
•
•
•
•
•
•
150 Bar H 2
Lithium
Fly wheel
Liq. N2
Pb-battery
Comp air
NormP H2
405
250
210
65
40
17
2.7
*without container
Wh/l
13500
13900
7850
39000*
1560
39000*
350
120
55
25
34
39000*
Field emission
CDC vs.
vs. SWCNT
• CDCs possess a
combination of unique
properties that make them
highly programmable for
a variety of purposes,
including flat panel
displays
Breakthrough in pure EDLC?
J. Chmiola,
Chmiola, G. Yushin,
Yushin, Y. Gogotsi,
Gogotsi,
C. Portet,
Portet, P. Simon, and P. L. Taberna
Anomalous Increase in Carbon Capacitance
at Pore Sizes Less Than 1 Nanometer.
Nanometer.
Science, 313, 1760-1763 (2006)
Supercapacitor R&D in Tartu Technologies
1999
2006
1600
1200
F 800
400 550
0
1600
Dependence of specific EDL capacitance on
pore structure of SkeletonC
CDC NbC
10
14
CDC ZrC
ZrC
Capacitan ce , µ F/cm 2
9
Average pore size
8
Average Pore Size (2V p /SD F T ), Å
CDC Mo2C
13
NbC
TiC
12
11
10
7
9
500
6
400
600
800
1000
600
700
800
900
Chlorination Temperature, °C
Chlorination Temperature, °C
APS = 2Vp/SDFT [Å
[Å]
1000
1100
Specific capacitance / F g
-1
; F cm
-3
Dependence of specific EDL capacitance on
pore structure of SkeletonC
120
F/g
110
ZrC
100
ZrC
90
NbC
80
NbC
F/cm3
70
60
50
10
11
12
APS / Angstrom
13
14
APS = 2Vp/SDFT [Å
[Å]
Capacitance of SkeletonC based EDLC
with different electrolytes
* Skeleton electrolyte - acetonitrile free
electrolyte particularly
made by proper mixing of well known
and widely used electrolyte solvents
Volumetric Capacitance / F cm
* 2.7V & ~25F EDLC
-3
16
* TEA/PC
TEMA/PC
TEMA/Skeleton electrolyte
14
Skeleton electrolyte
TEMA/PC
TEA/PC
12
10
8
6
4
2
0
0
* Patent pending
2
4
6
Applied Current / A
8
10
Power perfomance with different
electrolytes at variable temperatures
3.5
* TEA/PC
TEMA/PC
TEMA/Skeleton electrolyte
10-sec power, W cm
-3
3.0
* ~25F EDLC
* CCD 2.7V - 1.35V
2.5
2.0
1.5
Skeleton electrolyte
1.0
TEMA/PC
0.5
TEA/PC
0.0
-40
-20
0
20
40
60
80
Temperature , °C
A method for manufacturing
the nanoporous SkeletonC material
US patent application US11/407,202 (2006)
TiO2 + 2C + 2Cl 2 à TiCl4 +2CO
Coal
Stage B. Synthesis of titanium oxide (TiO 2)
TiO2
B
CO
powder from TiCl4
TiCl4 + O2 à TiO 2 + 2Cl2
C
Cl2
TiC
powder using the high-temperature reduction
O2
of TiO 2 with carbon (charcoal, lampblack)
D
TiCl4
TiO2 + 3C à TiC + 2CO
SkeletonC
A
TiO2 ore
Stage A. Beneficiation of the ore (rutile) through the
chlorination process.
Stage C. Synthesis of titanium carbide (TiC)
Stage D. Synthesis of SkeletonC using the hightemperature chlorination of titanium carbide
powder
TiC + 2Cl2 à C + TiCl4
Porosity parameters and apparent density
of SkeletonC
1
3000
d = 0.422x - 0.473
0.8
BET
2000
Ws
0.6
Vt
1500
Vm
1000
0.4
BET = (-1.47x + 5.64)1000
d
2
3 -1
R = 0.994
2500
Pore volume of SkeletonC [cm g ]
2 -1
BET surface of SkeletonC [m g ]
2
R = 0.989
0.2
500
2
2.2
2.4
2.6
2.8
3
3.2
3.4
x (C/TiO 2 mole ratio)
Porosity parameters and apparent density of SkeletonC examples 15 vs. C/TiO2 mole ratio; carbide synthesised at 1600°C.
Hypothetical reaction:
TiO2 + 2C à TiC + CO2
Experimentally is confirmed that carbothermal reduction of TiO2 requires T > 1000 °C.
It is also known that at temperatures above 1000°C the Boudouard’ equilibrium:
C+CO2 à 2CO
is strongly shifted to right side and therefore the mass-balance of TiC formation:
TiO2 + 3C à TiC + 2CO
What happens if less amount of carbon is involved in reaction?
TiO2 + (3-x)C à TiC1-x + 2CO
or
TiO2 + (3-x)C à (1-x/3)TiC + x/3TiO2 + (2-2x/3)CO
Relationship of EDL performance and
CDC synthesis parameters
2.5
3
132
130
2
128
126
124
122
120
1.5
0
5
10
15
20
Specific capacitance, F/g (KOH)
250
134
Specific power, W/cm
Specific capacitance, F/g (PC)
136
200
150
100
0.4
0.6
0.8
1
x in TiCx
%TiO2 in TiC/TiO2
CDC based capacitor with AN free electrolyte
TECHNICAL DATA
Capacitance ( 25 0 C )
Voltage
Current
Series Resistance
Energy
(at UR)
Power
Leakage Current (8h, 25°C)
Temperature
TiC Derived Carbon
100 F/cm3 125 F/g
Stored energy
13.3 Wh/L
Wh/L
carbon load in capacitor 48% vol.
DCC
Rated UR
Surge
Rated
Peak
ESR DC
ESR 100Hz
Stored
Specific
At rated current
Matched Impedance
Operating
1600
2.85
3.00
300
700
0.60
0.55
6.5
8.0
2.6
15.0
10
-30...+85
F
V
V
A
A
mΩ
mΩ
kJ
Wh/kg
kW/kg
kW/kg
mA
°C
1.8 Ah
13.3 Wh/L
4.3 kW/L
24.9 kW/L
Ragone plot of the advanced Supercap
Tartu Technologies
Supercapacitor
1600F, 2.85V
m=225gm
V=136cm3
Today of Tartu Technologies
90
60
400
30
0
200
3
2
1
0
100
0
25
MW SW CDC
CNT CNT
Pore Width / Angstrom
Usable energy Wh/L at 2.7V
10
8
5 international patent applications
2005 Y. data
6
~25 peer-reviewed articles in scientific journals
4
Collaboration with Toyota, Honeywell, Samsung etc.
0
es
s
Pa
na
so
ni
c
2
N
3 national patent applications
iG
l.
M
ax
w
el
Ta
l
rt
u
Te
h.
15
CDC
H2 wt. %
1atm, 77K
ac
h
5
NActC SActC
As
Pore Area / m g
2 -1
NbC derived SkeletonC
300
Capacitance F/cm 3
in organic
Future of CDC materials
• Is it good enough compared to the natural
or synthetic active carbons?
• Is it rare?
• Is it expensive?
Acknowledgment
• Marko Lätt wants to thank Doctoral School
of Materials Science and Technology at
University of Tartu for financial support.
• This work was partly carried out within the
Estonian Science Foundation grant no. 6455.
• Our colleagues at Tartu Technologies are
thanked for the kind assistance in preparation
of this paper.