LindaNazar AlmadenInstitute2009

Challenges of Lithium‐Sulfur and Lithium‐Air Cells: Old Chemistry New Advances
Old Chemistry, New Advances
David X. Ji, Kyu Tae Lee, and LF. Nazar
Dept of Chemistry; Waterloo Institute for Sustainable Energy (WISE)
D
t f Ch i t W t l I tit t f S t i bl E
(WISE)
Waterloo Institute for Nanotechnology (WIN)
University of Waterloo, Ontario, Canada
Professor Linda Nazar ([email protected])
IBM‐500
Mesoporous Carbon/Sulfur Composites :
Outline
OVERVIEW
From Li – ion intercalation to integration
MESOPOROUS CARBON/SULFUR COMPOSITES Advances with nanostructured materials
COMPARISON WITH Li‐AIR
The positives (and negatives)
CONCLUSIONS
Li‐ion Battery at Present: Intercalation Chemistry
Recent
Intercalation Cathodes:
5 eV
a) LiFePO4 Æ FePO4 + 1.0e- + 1.0Li+
Li1-xMO2
+
4 eV Æ Li MO + 0.7e- + 0.7Li+
b) LiMO
2
0.7
2
MLiMO
= Ni,2Co, Mn
3 eV
2 eV
V
-
1 eV
graphite
0
Specific
p
(a)
( ) and (b)
( ) between
0 capacities
eVp Li+/Lifor
155 – 185 mA•h/g, energy density limited
J. Goodenough, et. al, J. Electrochem Soc.,. 1997
“Green Energy” Needs Large Scale Energy Storage Systems
new demands for batteries
R
Renewables
bl
Portable High‐Energy Demand Devices
larger
g scale
Electric automotive i‐MIEV
LiCoO2
LiCoO2
implemented
1987
1991
LiFePO4
1997
Li[Ni,Co, Mn]O2, LiFePO4
implemented
2007
Future
Batteries
Q = 180 mAh/g
Q = 130 mAh/g
Q=
n•F
Mw• 3.6
36
(mAh/g)
Integrated
systems
Bolivia holds key to electric car future y
Sunday, 9 November 2008 Damian Kahya BBC News, Salar de Uyuni, Bolivia Mitsubishi, which plans to release its own electric car soon, estimates that the demand for lithium will outstrip supply in less than 10 years unless new sources are found. Beyond Li‐ion Batteries: Na2FePO4F
A2
A1
Na2FeIIPO4F
Vol = 852Å3
Fe
c
a
Reduction
b
Oxidation
3.7% vol change
NaFeIIIPO4F
Vol = 820Å3
Two – dimensional ion
t
transport
t
Low strain material on redox Ellis, Nazar et al., Nature Mater., 2007 Effect of Nano-Sizing
5
b)
Voltage (V)
4.5
Nano: 87% capacity
av 50x50x500 nm
4
a
3.5
3
2.5
400 nm: 36% capacity
500 nm
2
0
02
0.2
04
0.4
06
0.6
08
0.8
1
x in Li
F
x in Na
xNaFePO
xNaFePO44F
d)
Unusual “solid solution” behavior
c Li/Na exchange
Æ function of
Æ also substituted : (Na,Li)2[Fe, Co]PO4F
Stable cycling as LiFePO4
500 nm
Ellis, Nazar et al., Chem Mater., in press
b
0
Rate Capability
120
4.5
Voltage ((V)
Capacity (mAh//g)
a
100
4
80
60
40
20
35
3.5
Galvanostatic C/10
0
1
2
3
4
5
6
7
8
9
10
11
12
Cycle Number
3
C/10
2C
2.5
10C
1C
5C
2
c
0
20
40
60
80
Capacity (mAh/g)
b
100
120
Interconversion of (Na,Li) FePO4F
Li2FeIIPO4F
ion
red
Na2FeIIPO4F
ion
g
xchange
g
xchange
NaLiFeIIPO4F
LiI
ox
NaFeIIIPO4F
(Na,Li)FeIIIPO4F
LiFeIIIPO4F
Multifunctional: use either in Li or Na cell
- lower cost, less utilization of Li (electrolyte only)
- can be used as a Na-ion
Na ion battery for load
levelling on large scale
Next Generation Battery: Integration Chemistry
LiyX: High specific capacity
Goal: Higher energy density
L
Larger scale
l
4 eV
Low cost Challenges: Kinetics
+
Safer and environment friendly
3 V
3 eV
yLi + X
•Mass transport issues
2 eV
2 eV
LiyX
•Poor reversibility with bulk materials
1 eV
0 eV
‐
•Contact of reactants/products and /p
contact with current collector problematic
Li+/Li0
Î polarization, poor cycle life
l
l lf
Next Generation Battery: Integration Chemistry
LiyX: High specific capacity
Examples: 2 Li+//e‐ + O2 ↔ Li2O2
4 eV
4 eV
+
3 eV
2 eV
yLi + X
LiyX
‐
1 eV
0 eV
16 Li
16
Li+/e‐ + S
+ S8 ↔ Li
↔ Li2S S
Li+/Li0
Offer 3 ‐5 times energy density
of traditional intercalation materials
(max 220 mAh/g storage capacity ; 100 ‐200 Wh/kg energy density)
Comparative Capacities (Beattie et al, JECS 2009)
a
c
Unrealistic!
b
Batteries and Li‐Air Cells: Simple Comparison
‐
+
((+)) Current collector
Current collector
Positive electrode (LiMO2)
Electrolyte (alkyl carbonates, etc..)
Separator (new ceramic blended)
Separator (new ceramic blended)
Negative electrode (graphite)
(‐) Current collector
a
Li ion Battery
Li‐ion Battery
S2 + 4 Li+/e‐ ↔ 2Li2S O2 + 4 H+/e‐ ↔ 2H2O
O2 + 2 Li+/e‐ ↔ Li2O2
oxygen
oxygen
fuel
c
a a
Li‐S Battery
Li
S B tt
product: Li2S
stored in carbon cathodeb
a
Li‐Air Battery
Li
Ai B tt
product: Li2O2
stored in carbon cathode
FFuel Cell
l C ll
Product: H2O
eliminated Motivation for the Li‐S battery
Studied for several decades
S di d f
ld d
2Li + S ÍÎ Li2S
™LiMO2/C battery (M = Ni, Mn, Co)
™Li/S battery
OCV:
3.9 V
OCV:
2.1 V
440
Wh/kg
180
mAh/g
2500
Wh/kg
1675
mAh/g
Electrochemistry of the Sulfur Cathode
charge
charge I
II
S8 Li2S8 Li2S4
0% 12.5%
25%
discharge III
Li2S2
50%
Depth of discharge I: conversion of solid sulfur to soluble polysulfides
p y
II: polysulfides to solid Li2S2
III: solid Li2S2 to solid Li2S
Li2S
Example of integration chemistry: The Li‐S Battery
2Li + S ÍÎ
2Li + S ÍÎ Li2S theoretical capacity 1675 mAh/g
S
theoretical capacity 1675 mAh/g
typical Li‐S capacity: 500 mAh/g
¾ Low conductivity ¾ capacity fading —
i f di
lloss of active mass f i
Di h
Discharge
e‐
e‐
Charge
Polysulfide shuttle
a(Li2S6)
+
b(Li2S4)
Li+
Li+
Lithium
Li2S8
Separato
or
2 Li+
(Li2S2)/
(Li2S)
Li2S inactivated Li2Sx
• internal “short circuit”
SEI
Li2Sx/2
Li‐S Diametric Approaches: Contain or Let Free
Catholyte
Contained Cathode
‐
+
‐
+
a
c
c
a
a
Insoluble product: Li2S
stored in carbon cathode
a
b
b
a
Soluble product: Li2Sn
stored in electrolyte
Li‐S Battery for Unmanned Aerial Vehicles
a
c
Zehyr UAV ‐ Qinetiq
Powered at night by a SionPower Li‐S cell Record of 82 hours of continuous flight
Record of 82 hours of continuous flight
b
Progress towards improving the sulphur cathode
1) Adding absorbents, mixing porous carbon with sulphur
Disordered porous carbon
CNT Wang, et al. Carbon 2008, 46, 22
Zheng et al. Electrochimica
et al. Electrochimica 2006, 51, 1330 2006, 51, 1330
Î Lack of encapsulation, extensive precipitation of inactive Li2S on absorbent 2) Conducting polymer + sulphur: Low surface area of polymer (low active mass) high polarization – lower working potential p
Wang, et al. Adv. Funct. Mat. 2003, 13, 487 3) Innovations re Li negative electrode and electrolyte
3) Innovations re Li negative electrode and electrolyte
Solubilization of polysulphides – large electrolyte volume/low volumetric density
Sion Power
Stabilized capacity > 1000 mA h/g at practical rates rarely achieved
Mesoporous Carbon Encapsulation Strategy
Porous ‐ structured ‐ controllable
Interconnected
Channel structure: CMK-3
3D structure: CMK-8
Controllable morphology
Symmetry: P6mm
Symmetry: Ia3d
Tailoring Mesoporous Carbon Hosts
Surfactant free Nucleation Cooperative assembly
control
100 nm
Ji, Nazar Chem. Comm. 4288, (2008)
In situ CVD
Metal
phthalocyanine
+ SBA-15
I it
In situ carbonization
b i ti
G raphitic carbon
Intensity/ A.U.
A l holder
NiPc 900 o C 20h
NiPc 900 o C 3h
o
N iPc 800 C 20h
o
Sucrose 900 C 20h
10
15
20
25
30
35
40
2θ/ degree
Ji, Nazar et al, Chem. Mater 19, 374 (2007)
Lee, Nazar et al., Angew Chemie, 48, 5661, (2009)
Encapsulation of Sulphur Sulfur map
Empty
channels in
CMK-3
30 nm
Channels filled with S
Carbon map
CMK‐3—Conductive Nano‐chamber Reactor Assembly for Sulfur Active Mass Increases electrical conductivity
Î Intimate 3
Intimate 3‐dimensional
dimensional, multi electronic contacts multi electronic contacts
Allows egress of electrolyte to aid ionic conductivity through free space in channels
C t l
Controls sulfur particle size to nano dimensions
lf
ti l i t
di
i
Inhibits soluble polysulfides from diffusing away from cathode
Encapsulation Effect on Electrochemistry All at 168mA/g
Mixture: 25°C
Partial imbibition
With increase
in contact
in contact
temperature:
Complete imbibition
9 > doubled > doubled
capacity
9 no overcharge, irreversibilityy
9 reduced polarization
Conductivity Ensured Electrical Conductivity: CMK‐3: 0.25 S/cm El t i l C d ti it CMK 3 0 25 S/
CMK‐3/S: 0.21 S/cm
Ionic Conductivity: • Space is precisely tuned to accommodate swelling of S to Li2S
Molten S within pores
p
Solidificaton
( incomplete Filling)
Li2S formation
S formation
C/S – 70 wt%
Mesoporous carbon
Characteristics
Only very
small shuttle
process after
p
equilibration at
55°C
Quasi-equilibrium
C/10 (0.19 mA/cm-2)
Promising rate
behavior
C/5 (0.36 mA/cm-2)
CMK‐3/S/Hydrophilic Polymer Surface Modifier
Black: PEG modified
Red: no polymer
PEG = polyethylene glycol (Mw = 4600)
PEG = polyethylene glycol (Mw = 4600)
80% utili.
Discharge capacity
Surface‐bound PEG provides hydrophilic gradient to partition polysulfide ions For 1000 mAh/g capacity:
Î1400 Wh/kg based on total mass Î1400
Wh/kg based on total mass
of cathode (S + carbon + binder)
Black: PEG modified
Red:
no polymer
Black: Polymer decorated
Red: no polymer d
l
Î2330 Wh/l volumetric for cathode
Î 600 – 800 Wh/kg for a full cell
D. Ji, K T Lee, L.F. Nazar , Nature Mater., 8, 500 (2009)
Role of the Surface Modifier
• Increases the absorbing capacity of mesoporous carbon by increasing Increases the absorbing capacity of mesoporous carbon by increasing
hydrophilicity • Improves the ionic permeability of the composite
• Inhibits Li
I hibi Li2S precipitation on external surface of mesoporous carbon
S
i i i
l
f
f
b
CMK‐3/S
/
P‐CMK‐3/S
30th charge
30th charge
Summary: Tailored Nanostructured S/C Nanocomposites
ÎAchieve stable energy density of a full cell between 550 – 650 Wh/kg ÎFactor of 3‐5 over any conventional Li‐ion cell cell (100‐200 Wh/kg)
ÎSion Power: guarantees 350 Wh/kg for 50 cycles for Li‐S cell
Î Other cell configurations possible with cathode nanostructure: Î protected metallic Li negative electrodes
Î non –Li metal, high capacity negative electrodes
Î other surface modifiers and coatings…
Î polymer electrolytes….
Mesoporous Materials made Nano
Nano‐mesoporous silicate
Nano‐mesoporous carbon
Ji, Nazar Chem. Comm. 4288, (2008)
Bulk‐mesoporous silicate
Bulk‐mesoporous carbon
Agitation‐Friction Loading of S into Nano CMK‐3
a
c
b
Comparison with Li‐Air Cells
Comparison with Li‐Air Cells
Li – S vs Li‐air
S2 + 4 Li
+ 4 Li+/e‐ ↔ 2Li
↔ 2Li2S S
O2 + 2 Li
+ 2 Li+/e‐ ↔ Li
↔ Li2O2
O2
c
aa
Li‐S Battery
Rx of S within cathode with Li to f S i hi
h d ih i
form Li2S in carbon cathode
a
Li‐Air Battery
Rx of external O
f
l 2 with Li to form h
f
Li2O2 housed in carbon cathode
Role of carbon (or other) framework R
l f b b(
th ) f
k
• electronic contact to S/Li2S
‐ opt pore size ~ 4‐15 nm
• trap polysulfides Î Li2S
‐ tortuous pathway, sorbtive
• current delivery system to O2/Li2O2
‐ opt pore size? Pore clogging?
• plus polymer binder: houses Li2O2
‐ high pore volume > 2‐3 cc/g
• support for CATALYST
c
Volumetricc energy density (Wh/L)
a
Gravimetric energy de
ensity (Wh/kg
g)
Comparison of Cell ED (Hypothetical)
1600
1400
1200
1000
800
Calc’s for
Li-S
based on
Li2S
cathode
Commercialized
Graphite
Li (130%)
Si (9:1)
Si (5:5)
600
400
200
0
NMC
Li-S
Li-air Zn-air
3000
2500
2000
1500
for Li-S for OUR
cathode:
1340 Wh/l with Si
1025 Wh/l for 2x Li
excess
1000
500
0
b
NMC
Li-S
Li-air Zn-air
Commercialized
Graphite
Li (130%)
Si (9:1)
Si (5:5)
Calculation conditions
1. Cathode
Thickness: 100 μm
Electrode porosity: 20 vol.%
Volume ratio of active material: carbon+binder
= 9:1 for LiCoO2 (72 vol.% of LiCoO2 in total)
= 8:2 for Li-S & Li-Air (64 vol.% of Li2S or Li2O2 in total)
2 A
2.
Anode
d
Electrode porosity: 20 vol.%
Volume ratio of active material: carbon+binder = 9:1 for graphite
= 9:1 for Si (9:1)
= 5:5 for Si (5:5)
3. Separator 15 μm, Al & Cu current collectors: each 10 μm
c
Volumetricc energy density (Wh/L)
a
Gravimetric energy de
ensity (Wh/kg
g)
Comparison of Cell ED (Hypothetical)
1600
Calc for
Li-S
based on
S cathode
1400
1200
1000
800
600
Commercialized
Graphite
Li
Si
400
200
0
NMC
Li-S
Li-air Zn-air
3000
2500
Anode
2000
Commercialized
Graphite
Li
Si
1500
1000
500
0
b
NMC
Li-S
Li-air Zn-air
Conclusions
Increasing Complexity of Demands – and Materials
SONY Nexelion
SONY Nexelion
Sn/C/Co nanocomposite
Sn/C/Co
nanocomposite
negative electrode
Nano LiFePO4 for the positive
AltairNano: nano Li4Ti5O12 for negative
AltairNano: nano Li
for negative
COMMERCIAL
LiCoO2
Bulk‐intercalation
LiFePO4, Na,LiMPOxFy
Li4Ti5O12, TiO2(B)
Nano‐intercalation
Li/ C‐Sulfur
Nano‐integration
systems
ACADEMIC
Lithium – Air
Li + O2 ↔ Li2O2
Nano‐meso‐micro
Old Ideas Revisited
Fire and Brimstone: feu grégeois
“A
A sulfur
sulfur-and-carbon
and carbon pitch
pitch-based
based compound (the exact composition
of which was a closely guarded secret and is still a mystery today)
- the napalm of the Middle Ages” - was hurled at the Crusaders ~
1090 to unavail,, leading
g to the overtaking
g of Jerusalem
Sulfur Tower, Jerusalem
Feu grégeois tel que décrit dans le manuscrit
(Madrid)
Funding and Acknowledgments
Funding:
F di
NSERC (Discovery & Strategic)
NSERC Canada Research Chair
i Solid
in
lid State M
Materials
i l
GM Canada/USA
Toyota USA/Japan
Auto211
Research Team
Dr. Kyu Tae Lee
Dr. Prakash Badi
Dr. Katya Pomeransteva
Dr. T. N Ramesh
Collaborators
C ll b
t
Dr. Neil Coombs (U Toronto)
Prf. Gianluigi Botton (U McMaster)
NRC F
Fuell C
Cell
ll I
Institute
i
Prf. A. Sazanov (UW, ECE)
Prf. M. Wagemaker (TU Delft)
P f Thomas
Prf.
h
Bein
B
(LMU,
(
Germany)
G
)
David Ji
Brian Ellis
Robert Black
Scott Evers
Guang He
Si Hyoung Oh
Rajesh Tripathi
Hey Woong Park
Guang He