nano-composite materials for energy storage devices: impact of the
Post on 03-Feb-2022
4 Views
Preview:
TRANSCRIPT
www.nano-tech.gatech.edu
Gleb Yushin
yushin@gatech.edu; www.nano-tech.gatech.edu
School of Materials Science & Engineering
Georgia Institute of Technology, Atlanta, GA 30332, USA
NAATBatt, January 18, 2013
Nano-Composite Materials for Energy Storage Devices:
Impact of the Electrode Architecture
Contributors and Collaborators: Benjamin Hertzberg, Kara Evanoff, Jim Benson, Sofiane
Boukhalfa, Hyea Kim, Jung Tae, Alexandre Magasinski, Igor Kovalenko, Patrick Dixon,
Bogdan Zhdyrko, Igor Luzinov, and others
www.nano-tech.gatech.edu
Activities in Our Laboratory in the Past Years
Synthesis and
Characterization of
Porous Carbons
(primarily for EDLC
applications)
Synthesis, Modification
and Mechanical
Characterization of Metal
Nanostructures and
Nanostructured Films
Nano-Composite
Materials for Li-ion
Battery and
Supercapacitor
Applications
ACS Nano, 2011 Adv. Func. Mater., 2012
Adv. Func. Mater., 2011
Adv. Mater., 2011
Science, 2011
Electrochem. Comm., 2011
Adv. Ener. Mater., 2011
Adv. Ener. Mater., 2011
Small, 2011
Adv. Func. Mater., 2011 Environ. Science and Tech, 2011
Nature Mater., 2010
JACS, 2010
JACS, 2010
ACS Nano, 2010
J. Electrochem. Soc., 2010
Carbon, 2012
ACS Nano, 2011
Ener. Env. Science., 2012
Fundamental Studies of
Degradation Mechanisms
in Commercial Li-ion Cells
Carbon, 2012
will provide examples
www.nano-tech.gatech.edu
Improving Stability and Power Capabilities
of High-Energy Electrodes
Ability to store energy of Li-ion batteries is largely governed by the ability of their electrode materials to host high content of ions
Many active materials exhibit outstanding ability for ion storage but suffer from large volume changes during insertion/extraction of ions (rapid electrode degradation) and/or low electrical and ionic conductivity (low power density)
Rational design of the architecture of high-capacity electrodes allows one to overcome these limitations while still achieving up to 90 % of the theoretical energy storage
Multi-functionality of battery (supercapacitor) electrodes permit for weight savings of the system
Many examples in this presentations deal with Si anodes, but they are broadly applicable to various materials
www.nano-tech.gatech.edu
Vertically Aligned CNT - Based Electrodes
• Ultra-High electrical conductivity
• High thermal conductivity
• Thicker electrodes and thus smaller
contribution of inactive components
(separators, metal foils, etc.)
Traditional Electrodes
and Cell Architecture
• Low electrical conductivity
• Low thermal conductivity
• Heavy/bulky metal foils
• Low electrical conductivity
• Low thermal conductivity
• Heavy/bulky metal foils
www.nano-tech.gatech.edu
Si- coated Vertically Aligned CNT Anodes
0 50 100 150 200 2500
1000
2000
3000
4000
De
allo
yin
g
Ca
pa
city /
mA
h g
-1 Si
Cycle Index
C/20 C/2C/5
Evanoff, K. et. al, Advanced Materials, 2011 Patent pending
www.nano-tech.gatech.edu
Si-coated Vertically Aligned CNT Anodes
20 30 40 50 60 70 80 90 1000.1
1
10
100
1000
10000
Re
sis
tivity
/ O
hm
·cm
Temperature / oC
novel electrode based on Si and C coated VACNTs
conventional electrode composed of Si nanopowder
with carbon black additives and PVDF binder > 100 times lower electrical
resistance than that of
nanopowder electrode with
much higher density but
comparable thickness
Evanoff, K. et. al, Advanced Materials, 2011
20 30 40 50 60 70 80 90 1000.1
1
10
100
1000
10000
novel electrode based on Si and C coated VACNTs
conventional electrode composed of Si nanopowder
with carbon black additives and PVDF binder
Th
erm
al C
on
du
ctivity /
W·m
K-1
Temperature / oC
> 1000 times higher thermal
conductivity as compared to
nanopowder electrode with much
higher density but comparable
thickness
Excellent thermal properties of
the CNT-Cu interface
www.nano-tech.gatech.edu
Multifunctional Nano-Composite Fabric
Traditional Electrodes
and Cell Architecture
• Low electrical conductivity
• Low thermal conductivity
• Heavy/bulky metal foils
• No mechanical strength
Uncoated portion of CNT fabric
also serves as a Current Collector Strong and flexible Mg- or
Si- coated CNT fabric as an
Anode
15-50 µm
Anode
15-50 µm
Cathode
Active coating (e.g., Si or Mg for anodes and LiV2O5 for cathodes)
Multifunctional Nano-Composite Fabric
• Ultra-High electrical conductivity
• High thermal conductivity
• No metal foil current collectors needed
• Enhanced safety (when solid electrolyte is
used)
• High mechanical strength / multi-
functionalilty
solid electrolyte
www.nano-tech.gatech.edu
Si-C Nano-Composite Anode Fabric
20 40 60 80 100 120 1400
50
100
150
200
250
300
350
400
450
500
550
600
Regular Graphite-PVDF Anode on Cu foil
Li E
xtr
actio
n C
ap
acity (
mA
h/g
)
Cycle Index
Multifunctional Si-on-CNT Fabric Anode (54% Si)
(limited Li insertion to avoid Li insertion into CNT)
Regular Graphite Anode
Si-on-CNT Fabric Anode
1 mm
40 mm
Note:
Density of 90 um Graphite coating < 1.6 g/cc
(each side) ; Density of 18 um Cu = 9 g/cc
Evanoff, K. et. al, ACS Nano, 2012
www.nano-tech.gatech.edu
Si-C Nano-Composite Anode Fabric
0.0 0.1 0.2 0.3 0.4 0.5 0.60
25
50
75
100
Si-CNT fabric before cycling
Si-CNT fabric after cycling
Str
ess / M
Pa
Strain / %
25
50
75
100
125
150
Str
uctu
ral ste
el A
36
Cast iron A
ST
M 4
0
Ti 99.5
%
Al allo
y 7
13
Al allo
y 5
14
Bra
ss
Cu 9
9.5
%
Cast iron A
ST
M 2
0
Specific
Str
ength
/ k
Nm
kg
-1
Al allo
y 4
43
Si-
CN
T
fab
ric
Evanoff, K. et. al, ACS Nano, 2012
0 5 10 15 20 25 30 350
25
50
75
100
125
150
175
Ar annealing at 500 oC
CNT fabric after Str
ess / M
Pa
Strain / %
synthesized CNT fabric
www.nano-tech.gatech.edu
Metal Oxide / Carbon
Nanocomposites for Supercapacitors
(a)
(b)
(c)
(d)
1 µm
1 µm
1 µm
1 µm
not coated CNTs
100 ALD cycles
300 ALD cycles
500 ALD cycles
0 100 200 300 400 50060
80
100
120
140
160
180
Ave
rag
e t
ub
e d
iam
ete
r (n
m)
Number of ALD cycles
In an ideal case ALD is a surface-limited process, the
average coating thickness or the average tube diameter
should increase proportionally to the number of the ALD
cycles
An ImageJ software analysis of multiple SEM micrographs
reveals linear increase in the average tube diameter with the
number of ALD cycles, suggesting that the time allocated for
the diffusion of the precursor gases into the porous structure
in each cycle was sufficient for the reaction to be surface
kinetics-controlled
Coating thickness
increases at
0.1nm/cycle
www.nano-tech.gatech.edu
5 10 15 200
400
800
1200
1600
Sp
ecific
Ca
pa
cita
nce
(F
g(V
Ox)-1
)
Current Density (A g-1)
100 ALD cycles
300 ALD cycles
500 ALD cycles
5 10 15 20
0
100
200
300
400
500
600
Sp
ecific
Ca
pa
cita
nce
(F
g-1)
Current Density (A g-1)
100 ALD cycles
300 ALD cycles
500 ALD cycles
not coated CNT electrode
0 4 8 12 16-0.6
-0.3
0.0
0.3
0.6
Vo
lta
ge
(V
)
Time (s)
20 A g-1 scan rate
100 ALD cycles
300 ALD cycles
500 ALD cycles
IR
Vanadium oxide capacitance >
1000 F/g at very high current
density of 20 A/g
Very small IR drop at 20 A/g
S. Baukhalfa, K. Evanoff and G. Yushin, Energy & Env. Science, 2012
Metal Oxide / Carbon Nanocomposites
for Supercapacitors
www.nano-tech.gatech.edu
Catalyst-Free Al Nanowire Growth by CVD
• Trimethylamine alane (TMAA) as an organometallic CVD precursor
• Catalyst-free
0 1 2 3 4 5
Al
Inte
nsi
ty (
a.u
.)
Energy (keV)
O
(a)
Cu foil Forest of Al nanowires
2 cm
Gas flow
(b)
100 nm
(c) Al nanowires on Cu
Limitation of the CNT:
- low DC conductivity (compared to Al and Cu)
- low concentration of dangling bonds
Metal nanowires:
- typically grown electrochemically using AAO template
- CVD growth (as CNTs) might offer more scalable process
J. Benson et al., ACS Nano, 2011
www.nano-tech.gatech.edu
ALD-coated Al Nanowires
Battery-like AND pseudocapacitor-like behavior
Gravimetric capacitance of up to 887 F/g is 4-10 time higher than C
Volumetric capacitance of 1390-1950 F/cc is10-40 times higher than
that of C in the same electrolyte
(a) Al nanowire core
Cu foil
VOx coating
1.0 1.5 2.0 2.5 3.0
-3000
-2000
-1000
0
1000
2000
3000
porous carbon
used in commercial
supercapacitors
Ca
pa
cita
nce
(F
g-1)
Potential vs. Li/Li+ (V)
VOx coating on
Al nanowires
(e)
0.1 1 10 1000
100
200
300
400
500
600
700
800
900
porous carbon
used in commercial
supercapacitors
Capa
citance
(F
g-1)
Scan Rate (mV s-1)
50 nm VOx coating
VOx - coated
Al nanowires
300 nm
(b)
(f)
(c)
200 nm amorphous
VOx coating
Al nanowire
core
1 2 3 4 5 6
Al
O
Energy (keV)
Inte
nsity (
a.u
.)
V
(d)
J. Benson et al., ACS Nano, 2011
www.nano-tech.gatech.edu
Drop-in Replacement: Si-C Nanocomposite Powder
produced using Hierarchical Bottom-up Assembling
Si nanoparticles’
assembly on the surface
of annealed CB
Assembly of Si-
coated CB particles
into rigid spherical
granules
Annealed carbon
black (CB)
100 nm
Si
Magasinski, A. et. al, Nature Materials, 2010
• Uniformity of the deposited Si nanoparticles
• No volume changes during Li insertion/extraction
• Compatibility with existing manufacturing
technologies (drop-in replacement)
• High electrical & thermal conductivity
Patent pending
www.nano-tech.gatech.edu
Environmentally-friendly process: (a) growing algae captures CO2 and
produced O2; (b) alginate (as a Na-alginate) is produced from brown algae
by boiling it in a soda solution (no need for extensive chemical treatment; in
contrast, CMC synthesis involves the alkali-catalyzed reaction of cellulose
with chloroacetic acid to introduce carboxy groups); (c) solvent – water (in
contrast, PVDF requires NMP)
Alginate is extracted from
brown algae, which is: (a) the
fastest growing plant on the
planet, (b) does not need
agricultural land
Studies of Inactive Components: Electrolytes, Binders, etc.
I. Kovalenko et al., Science, 2011
www.nano-tech.gatech.edu
Recent Activities in Our Laboratory
Cathodes for Mg-ion
Batteries (potentially
higher energy and
lower cost than Li-ion)
Anodes for Na-ion
Batteries (potentially
higher power and lower
cost than Li-ion)
Nanostructured & smooth
electro-deposition of metal
coatings on various
substrates (foils, carbon
fibers, CNTs) :
Mg and Al
• In contrast to Li, Mg
foil can be used as an
anode in Mg-ion cells
(no dendrites)
• Greatest challenge -
high-rate / high
capacity cathodes
(large +2 ion charge)
• Nearly all cathode
structures for Li-ion
batteries can be
effectively used for
Na-ion batteries
• Greatest challenge –
high-rate / high-
capacity anodes
(graphite does not
work)
• Uniform electro-deposition
of nano-grained metal
coatings is a challenge
• Applications range from
structure support to energy
storage (even as counter
anodes in half cells)
www.nano-tech.gatech.edu
Recent Activities in Our Laboratory
High-Energy
Conversion-type
Cathodes for Li-ion
batteries
• Matching high-
capacity anodes with
high-capacity cathodes
may allow 2-3 times
improvements in the
volumetric energy
density of Li-ion cells
Room Temperature Solid
Inorganic Electrolytes for
Li-ion batteries
• Higher voltage
• Higher safety
• Potentially longer cycle life
• Broader operational T
• Potentially higher charge
rate
Li-S & Na-S Cells
• Low-cost, high-energy
density systems
top related