Nanofibers for Energy Storage and Conversion Laboratory€¦ · Triaxial Nanofiber cross-section...
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RESEARCH POSTER PRESENTATION DESIGN © 2011 www.PosterPresentations.com We combine experiments and simulations to study structure-property performance correlation in nanofiber-based novel materials for energy storage and conversion devices such as fuel cells, super-capacitors, batteries and solar cells. INTRODUCTION- NANOFIBERS Proton exchange membrane fuel cell (PEMFC) converts the chemical energy liberated during the reaction between hydrogen and oxygen to electrical energy. Limitation of State-of-the-art Fuel Cells: High cost of platinum catalyst has been one of the key challenges that has prevented the broad deployment of fuel cells for transportation application Objective: To study structure-property-performance correlation in nanofiber-based fuel cell cathodes that maximize triple phase reaction surfaces and enhance platinum utilization, thereby reducing cost. NANOFIBERS FOR FUEL CELLS Supercapacitors (or electrical double-layer capacitors) are energy storage devices that store charge by adsorbing ions on the surface of highly porous carbon materials. Carbon nanofibers with well-controlled, hierarchical pore structure exhibiting specific surface area of 1500-2000 m 2 /g are ideal candidates for such devices. NANOFIBERS FOR SUPERCAPACITORS NANOFIBERS FOR BATTERIES Batteries are energy devices that convert chemical reaction energy to electrical energy FUNDING AND CONTACT Vibha Kalra E-mail: [email protected] Ph: 215-895-2233 http://www.chemeng.drexel.edu/kalraresearchgroup/default.aspx Nanofibers for Energy Storage and Conversion Laboratory Group Members: Chau Tran, Qinsu Niu, Nataliia Mozhzukhina, Alda Kapllani, Alice Hu, Chris Curran PI: Vibha Kalra Nanofibers are fabricated via a process called electrospinning that uses strong electric field to accelerate and thin a polymer solution/melt jet forming nanoscale fibers Why Nanofibers? Nanofibers are 10-100 times smaller than those produced from conventional mechanical spinning High surface area leads to enhanced efficiencies in energy devices Interconnected porous structure with tunable porosity enhances mass transport Versatility of the electrospinning process Electrospinning Set-up SEM image of a typical nanofiber mat Combining Multi-functionalities via Core-Shell Electrospinning 500 nm Coaxial Nanofibers Triaxial Nanofiber cross-section 200 nm Schematic- Fabrication of Porous Carbon Nanofibers Nanofibers of Carbon Precursor/Sacrificial Polymer Blend High temperature Calcination to selectively remove sacrificial polymer forming Porous Carbon Nanofibers As-made Blend Nanofibers (Pre-Calcination)-SEM Images Porous Carbon Nanofibers (Post-Calcination)-SEM Images Longitudinal section-TEM Image -0.2 0 0.2 0.4 0.6 0.8 1 0 20 40 60 Voltage (V) Time (s) -4.E-3 -2.E-3 0.E+0 2.E-3 4.E-3 -1.0 -0.6 -0.2 0.2 0.6 1.0 Fabrication and Structural Characterization Performance Characterization Cross-section- TEM Image showing co- continuous carbon and pore phase 50 nm Current (Amp) Voltage (V) 174.43 F/g Galvanostatic charge-discharge measurements Cyclic Voltammetry Measurements 50 nm Lithium-air is a novel battery chemistry that utilizes oxidation of pure lithium metal at the anode and reduction of oxygen at the air-cathode to produce electricity Cathode Reaction (discharge): 2Li + + 2e - + O 2 Li 2 O 2 They can theoretically provide 2 orders of magnitude higher energy density than the state-of-the art Li-ion batteries and therefore hold enormous potential for all-electric vehicles. Fabrication of nanostructured air cathodes that optimize transport of all reactants (air, Li + ions, and electrons) to the active catalyst surfaces and provide enough spaces for solid lithium oxide products. Nanofibers with tunable porosity and internal structure will serve as excellent cathodes. 200 nm 1 mm SEM Micrograph of Manganese Oxide Nanofibers, potential catalyst for Li-air batteries High Magnification Image showing MnO x Nanocrystals within Nanofibers XRD Data showing MnO x peaks 500 nm Core-Shell Nanofibers with carbon core and MnO x nanocrystal shell Molecular Dynamics Simulation Snapshots showing formation of lamellar domains under extensional flow Critical Requirement for Successful Development of Li-air Batteries Schematic of Ideal Multiphase boundary in Li-air cathode TEM Image of microtomed nanofiber sections showing co-continuous morphology of PAN (light region) and Nafion (dark region) Super-porous pure nafion nanofibers with potential application in fuel cells and as high sensitivity sensors Nano-engineered materials with simultaneous proton and electron conductivity Addition of polyacrylonitrile enhances extensional viscosity of Nafion to enable electrospinning Pure Nafion in DMF Nafion /PAN blend in DMF
Transcript of Nanofibers for Energy Storage and Conversion Laboratory€¦ · Triaxial Nanofiber cross-section...
RESEARCH POSTER PRESENTATION DESIGN © 2011
www.PosterPresentations.com
We combine experiments and simulations to study structure-property
performance correlation in nanofiber-based novel materials for energy
storage and conversion devices such as fuel cells, super-capacitors,
batteries and solar cells.
INTRODUCTION- NANOFIBERS
Proton exchange membrane fuel cell (PEMFC) converts the chemical energy
liberated during the reaction between hydrogen and oxygen to electrical energy.
Limitation of State-of-the-art Fuel Cells: High cost of platinum catalyst has
been one of the key challenges that has prevented the broad deployment of fuel
cells for transportation application
Objective: To study structure-property-performance correlation in nanofiber-based
fuel cell cathodes that maximize triple phase reaction surfaces and enhance
platinum utilization, thereby reducing cost.
NANOFIBERS FOR FUEL CELLS
Supercapacitors (or electrical double-layer capacitors)
are energy storage devices that store charge by
adsorbing ions on the surface of highly porous carbon
materials.
Carbon nanofibers with well-controlled, hierarchical pore
structure exhibiting specific surface area of 1500-2000
m2/g are ideal candidates for such devices.
NANOFIBERS FOR SUPERCAPACITORS
NANOFIBERS FOR BATTERIES Batteries are energy devices that convert chemical reaction energy to electrical energy
FUNDING AND CONTACT
Vibha Kalra
E-mail: [email protected]
Ph: 215-895-2233
http://www.chemeng.drexel.edu/kalraresearchgroup/default.aspx
Nanofibers for Energy Storage and Conversion Laboratory
Group Members: Chau Tran, Qinsu Niu, Nataliia Mozhzukhina, Alda Kapllani, Alice Hu, Chris Curran
PI: Vibha Kalra
Nanofibers are fabricated via a process
called electrospinning that uses strong
electric field to accelerate and thin a
polymer solution/melt jet forming
nanoscale fibers
Why Nanofibers?
Nanofibers are 10-100 times smaller than those produced
from conventional mechanical spinning
High surface area leads to enhanced efficiencies in
energy devices
Interconnected porous structure with tunable porosity
enhances mass transport
Versatility of the electrospinning process
Electrospinning Set-up
SEM image of a typical nanofiber mat
Combining Multi-functionalities via Core-Shell Electrospinning
500 nm
Coaxial Nanofibers
Triaxial Nanofiber cross-section
200 nm
Schematic- Fabrication of Porous Carbon Nanofibers
Nanofibers of Carbon
Precursor/Sacrificial Polymer Blend
High temperature Calcination to
selectively remove sacrificial polymer
forming Porous Carbon Nanofibers
As-made Blend Nanofibers (Pre-Calcination)-SEM Images
Porous Carbon Nanofibers (Post-Calcination)-SEM Images
Longitudinal
section-TEM Image
-0.2
0
0.2
0.4
0.6
0.8
1
0 20 40 60
Vo
ltag
e (
V)
Time (s)
-4.E-3
-2.E-3
0.E+0
2.E-3
4.E-3
-1.0 -0.6 -0.2 0.2 0.6 1.0
Fabrication and Structural Characterization
Performance Characterization
Cross-section-
TEM Image
showing co-
continuous
carbon and
pore phase
50 nm
Cu
rre
nt
(Am
p)
Voltage (V)
174.43 F/g
Galvanostatic charge-discharge measurements Cyclic Voltammetry Measurements
50 nm
Lithium-air is a novel battery chemistry that utilizes
oxidation of pure lithium metal at the anode and reduction
of oxygen at the air-cathode to produce electricity
Cathode Reaction (discharge): 2Li+ + 2e-+ O2 Li2O2
They can theoretically provide 2 orders of magnitude
higher energy density than the state-of-the art Li-ion
batteries and therefore hold enormous potential for
all-electric vehicles.
Fabrication of nanostructured air cathodes that optimize transport of all
reactants (air, Li+ ions, and electrons) to the active catalyst surfaces and
provide enough spaces for solid lithium oxide products. Nanofibers with
tunable porosity and internal structure will serve as excellent cathodes.
200 nm
1 mm
SEM Micrograph of Manganese Oxide Nanofibers, potential catalyst for Li-air batteries
High Magnification Image showing MnOx Nanocrystals
within Nanofibers
XRD Data showing MnOx peaks
500 nm
Core-Shell Nanofibers with carbon core and
MnOx nanocrystal shell
Molecular Dynamics Simulation Snapshots showing formation of
lamellar domains under extensional flow
Critical Requirement for Successful Development of Li-air Batteries
Schematic of Ideal Multiphase boundary in Li-air cathode
TEM Image of microtomed nanofiber sections showing
co-continuous morphology of PAN (light region) and
Nafion (dark region)
Super-porous pure nafion nanofibers
with potential application in fuel cells
and as high sensitivity sensors
Nano-engineered materials with simultaneous proton and electron conductivity
Addition of polyacrylonitrile enhances extensional viscosity of Nafion to enable electrospinning
Pure Nafion
in DMF
Nafion /PAN
blend in DMF
