nrc-london (capabilities in supercapacitors) 2016-17
TRANSCRIPT
NRC-AST-London
Capabilities in
the development of
supercapacitors
November 2016
NRC-AST-London, November 2016
Electric Energy Storage Devices
2
•stores energy using
chemical reactions
happening between
an electrolyte, a
positive electrode
and a negative
electrode.
stores more energy than
ordinary capacitors by
creating a double layer
of separated charges
between two plates
made from porous,
typically carbon-based
materials .
consists of two
conducting surfaces
separated by an
insulating material
(dielectric).
Stores energy in an
electric field.
NRC-AST-London, November 2016
Electric Energy Storage Devices
3
• Supercapacitors and batteries are complimentary technologies!
DEVICE BATTERY SUPERCAP CAPACITOR
CHARGING TIME hours msec - minutes µsec - msec
DISCHARGING
TIME
minutes -
months msec - minutes µsec - msec
CYCLE LIFE 200 - 1000 106 -108 106 -108
SPECIFIC POWER
(W/Kg) < 500 1000 - 3000 > 10,000
SPECIFIC ENERGY
(Wh/Kg) 50 - 300 0.5 - 5 < 0.01
NRC-AST-London, November 2016
Supercapacitors
4
Ideal devices for delivering a
quick surge of power
Stop-start applications
Regenerative braking
Power vehicle accelerations
Provide power during stops
(radio, lights, air conditioning) ,
while battery provides range
Cold starts
X. Luo et al. / Applied Energy 137 (2015) 511–536
NRC-AST-London, November 2016
Supercapacitors: Challenges
5
1) Improve performance
• Increase the energy output
− high surface area nano-carbons
− high capacitance metal oxides or
conducting polymers
• Increase the power output − increase electronic conductivity of active
materials
− texturing current collectors (decrease
charge transfer resistance)
− highly porous separators (increase ion
mobility)
• Increase voltage that device can handle − metal oxides in aqueous medium (2V)
− ionic liquid electrolytes (4V)
2) Decrease costs Graphic from: Zhang et al., Chem. Soc. Rev., 38
(2009) 2520-2531.
NRC-AST-London, November 2016
R&D on Supercapacitors at NRC-AST London
6
Active materials - Manganese oxides of different oxidation
states, Graphene, Carbon nanotubes etc.
Current collector – Surface modified and coated Al and SS
Electrolyte - Aqueous and organic electrolytes
Cell design and Testing – Symmetry and asymmetry cells
NRC-AST-London, November 2016
Active Materials: Electrochemical testing of manganese
oxides of different oxidation states in aqueous
supercapacitors
7
Crystalline Mn2O3 Crystalline Mn3O4 Amorphous MnOx
Crystalline Mn2O3
Crystalline Mn3O4 (Low T)
Amorphous MnOx
Crystalline Mn3O4 (high T)
NRC-AST-London, November 2016
Current Collectors: Electrochemical testing of surface
roughened stainless steel and Al current collectors in
supercapacitor cells
8
• Higher interface area with the active layer
• Better adhesion of the active materials
Lower cell resistance (Conventional symmetric carbon-based cell in mild aqueous electrolyte)
Impedance of SS and Al current collectors
NRC-AST-London, November 2016
Graphene:
Preparation: laser photochemical/photothermal –
reduction of graphite oxide
9
NRC-AST-London, November 2016
Graphene:
Characterization: SEM and XRD
10
Graphite oxide (GO)
NRC-AST-London, November 2016
Electrode Material:
100% Laser fabricated Graphene
Electrolyte: 0.5 M K2SO4 in H2O
Separator: Gore PTFE
Current collector: Au
Electrode area 18 mm diameter
Graphene:
Characterization: Electrochemical performance in Symmetry
Supercapacitors
11
NRC-AST-London, November 2016
Graphenes:
Preparation: Synthesis of vertically arranged graphene on Al
12
The maximum mass load of material deposited was 110 mg/cm2
Mass load 2 mg/cm2
NRC-AST-London, November 2016
Graphene:
Characterization: Electrochemical performance of vertically
arranged graphene in Symmetry Supercapacitors
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13
0 50 100 150 2000
20
40
60
80
100
120
140
160
Gra
ph
en
e c
ap
acit
an
ce
(F
/g)
Scan rate (V/s)
NRC-AST-London, November 2016
Carbon nanotubes:
Preparation: Synthesis of vertically arranged CNTs on Al
14
• The maximum mass load of material deposited was 680 mg/cm2
• The material will be characterized for supercapacitor applications in near future
NRC-AST-London, November 2016
Capabilities in Specialty Coatings and Microfabrication
NRC-AST-London
15
Contact information:
Dr. Evgueni Bordatchev
Team Leader
1-519-430-7107, [email protected]
Dr. Dongfang Yang
Research Officer
1-519-430-7147, [email protected]
Dr. Mihnea Ionescu
Research Officer
1-519-430-7124, [email protected]