________________________________________________________________________________
Electrochemical Power Sources for fighting Global Warming
Bruno ScrosatiLaboratory for Advanced Batteries
and Fuel Cell Technology
21%
24%
36%
4%
7%
6% 1% 0.5%
21%
24%
36%
4%
7%
6% 1% 0.5%
21%
24%
36%
4%
7%
6% 1% 0.5%
The energy forms used in the World today
Italy
Fin
lan
d
Fra
nce
Germ
an
y
Gre
ece
Neth
erl
an
ds
Port
ug
al
UK
Sp
ain
Sw
ed
en
0
100
200
300
400
500
600
Production from fossil and nuclear sources
Production from renewable sources
The production from renewable sources in Europe / TWh (2005)
Derived from “Nuova Energia”N. 6, 2006
UE 1
5B
elg
ium UK
Neth
erl
an
ds
Irela
nd
Lu
xem
bu
rgG
erm
an
yG
reece
Fra
nce
Italy
Sp
ain
Port
ug
al
Den
mark
Fin
lan
dS
wed
en
Au
stri
a
0
10
20
30
40
50
60
70
80
2005 data aims for 2012
The production from renewable sources in Europe:comparison between 2005 data and the aims for 2010(% over consumptions)
Derived from “Nuova Energia”N. 6, 2006
21%
24%
36%
4%
7%
6% 1% 0.5%
21%
24%
36%
4%
7%
6% 1% 0.5%
21%
24%
36%
4%
7%
6% 1% 0.5%
The energy forms used in the World today?
Gba
/ yea
rG
ba/ y
ear
Worldwide production of oil & natural gas
26%9%
2%
43%79%
66%49%
19%
8%
Percentage of total0 50 100
OPEC
US
ConsommationProductionRéserves
26%9%
2%
43%79%
66%49%
19%
8%
0 50 100
Others
OPEC
US
ConsumptionProductionReserves
26%9%
2%
43%79%
66%49%
19%
8%
Percentage of total0 50 100
OPEC
US
ConsommationProductionRéserves
26%9%
2%
43%79%
66%49%
19%
8%
0 50 100
Others
OPEC
US
ConsumptionProductionReserves
World World oiloil reservesreserves//consumptionconsumptionHousehold
17%Others
21%
Air5.4%
Industry26% Roads
44%
Sea3.5%
Railways4%
C8H18 + 12.5 O2 8CO2 + 9 H20----------- NOx
C.O.V
Household17%
Others21%
Air5.4%
Industry26% Roads
44%
Sea3.5%
Railways4%
Household17%
Others21%
Air5.4%
Industry26% Roads
44%
Sea3.5%
Railways4%
C8H18 + 12.5 O2 8CO2 + 9 H20----------- NOx
C.O.V
C8H18 + 12.5 O2 8CO2 + 9 H20----------- NOx
C.O.V
C8H18 + 12.5 O2 8CO2 + 9 H20----------- NOx
C.O.V
DetailedDetailed oiloil consumptionconsumption
Oil: social and economic stakes
..to better implement renewable energies in our day-to-day livesSun doesn’t shine on demands…Wind doesn’t blow every days..
Cost-efficient, long-life, high-power energy electrochemical power sources (e.g. batteries or fuel
cells) are urgently needed!
To control environment pollution and..
1% 0.5%6%4% 1% 0.5%6%4%
How we can we address the CO2 issue and control the pollution in urban area ?
Among other actions, the replacement of a large fraction of internal combustion vehicles with controlled-emission (hybrid car) or zero emission (hydrogen car) is urgently needed!
Advanced energy storage systems, i.e. cost-efficient, long-life, high-power energy storage systems, i.e., batteries or fuel cells, are needed to meat this goal!
WHY HEV?
Source : International Energy Agency - http://omrpublic.iea.org/ - Feb 2006
Crude Oil Demand, worldwide, million tons, 1973-2005
0
500
1000
1500
2000
2500
3000
3500
4000
4500
1973 2005
Mill
ion
tons
per
yea
r
Transport Others
Price of the WTI barrel of oil, US $
0
10
20
30
40
50
60
70
1973 2000 2005 2006(Prev.)
US
$ /
barr
el
CO2 Emissions from fuel combustions, Million tons of
carbon, worldwide, 1970-2005
0
5000
10000
15000
20000
25000
30000
1970 2005
Mill
ion
tons
of C
From A. Madani, BATTERIES 2006, Paris, June 2006
HEV MARKET
HEV sold per year, units, worldwide,2000 - 2005
0
50.000
100.000
150.000
200.000
250.000
300.000
350.000
200020012002200320042005
Uni
ts
TOYOTA OTHERS
HEV sold per year, units per country,2000-2005
0
50.000
100.000
150.000
200.000
250.000
300.000
350.000
200020012002200320042005
Uni
ts
USA JAPAN EUROPE OTHERS
HEV MARKET WORLDWIDE GROWTH 04/05: +86%
Source : The Rechargeable Battery Market 2005-2015, AVICENNE, March 2006From A. Madani, BATTERIES 2006, Paris, June 2006
FOTO HYBRID CAR
.
Lithium batteries can do the job…..
…provide that they can assure, high energy, low cost safety and high rates!
The hybrid car, HEV
…. however, new types of batteries having higher energy density and lower cost than Ni-MH, are urgently needed to assure high performance and market competitiveness.
A nickel-metal hydride batteries is presently used as the energy storage unit in HEVs …..
The lithium ion battery
Conventional lithium/ion batteries are based on the following electrochemical system:
Anode: grafite
Electrolyte: liquid solution of a lithium salt in an organic solvent mixture
Cathode: layered LiMO2 lithium oxide, e.g. LiCoO2
The lithium-ion rechargeable battery
Process: yC + LiCoO2 LixCy + Li(1-x)CO2 ; x ~ 0.5 ; ~ 4V
Lithium ions are exchanged between the two electrodes by reversible extraction and insertion from and in open host structures with a concomitant removal and addition of electrons.
High Power
High Capacity
Power-Tools
Robot
Cordless-Applications
Cellular Phones& Note-PCs
Shaver
PDADSC
HEV
Mobile Applications
MP3
Camcorder
Power Applications
Lithium ion battery is the power sources of choice in a large range of consumer electronic devices!
However, lithium batteries fall short of satisfying needs for high energy for application in more demanding markets, such as efficient use of renewable energy and hybrid vehicles.If improvements in energydensity and safety are obtained, the lithium ion battery can enterin the HEV market!
Long Term HEV Battery forecast
HEV market, million units, worldwide, 2010-2015
0
1
2
3
4
5
6
2005
2007
2009
2011
2013
2015
Num
ber o
f HEV
sol
d w
orld
wid
e (M
illio
n)
0%
2%
4%
6%
8%
10%
12%
14%
16%
HEV (million) % of Li-ion
HEV BATTERY Market, M US$, Worldwide, 2005-2015
0
1000
2000
3000
4000
5000
6000
20052006200720082009201020112012201320142015
M U
S$NiMH Li-ion
From A. Madani, BATTERIES 2006, Paris, June 2006
ENERGY DENSITY
So far, the energy density of lithium ion batteries has been improved by engineering cell optimization, however, still keeping the original chemistry.
The limit has been now reached and jumps in energy density can only be obtained by renewing the overall cell chemistry.
Cathodes: Lithium manganese spinels and lithium iron phosphate phospholivines, lithium manganese layered.
Pot
entia
l vs.
Li/L
i+(V
)
Capacity (A h kg-1)
0
1
2
3
4
200 400 600 800 1000 3800 4000
GraphiteDisordered carbons
Composite alloys [Sn(O)-based]
3d-Metal oxides
Nitrides LiMyN2
Li metal
Si
MnO2 Vanadium oxides[V2O5, LiV3O8]
Olivines [LiFePO4]Li1-xNi1-y-zCoyMzO2
Li1-xCo1-yMyO2
Manganese spinels Li1-xMn2-yMyO4
Li1-xMn1-yMyO2
Cathode
Anode
Anodes: lithium metal alloys and lithium titanium oxides
Various electrode materials are suitable for progress in lithium battery technology
Courtesy of Prof. K. Kanamura, Tokyo Metropolitan University
SAFETY
Safety is still an issue for conventional C/ LiPF6-EC-DMC/ LiCoO2 lithium-ion batteries.
In addition to energy density, also safety is a keyparameter for batteris designed for HEV applications
Dell computer burnt in the conference in Osaka in June 2006
Approaches to improve safety:
Use of electrode combinations operating within the stability window of the polymer electrolyte. (plastic novel types of lithium-ion batteries)
Replacement of liquid electrolytes withlithium conducting polymer electrolytes.
Solvent-free membranes, formed by blending , poly(ethylene oxide), PEO, with a lithium salt, LiX(SPEs)
Polymer electrolytes
Two main types
Liquid-polymer hybrid membranes, formed by formed by trapping liquid solutions (e.g., a LiPF6-PC-EC solution ) in a polymer matrix (GPEs).
POLYMER ELECTROLYTES
Gel-type membranes, formed by trapping liquid solutions (e.g., a LiPF6-PC-EC solution ) in a polymer matrix (e.g. a poly(vinylidene fluoride), PVdF matrix (GPE).
0 5 10 15 20 25 30 35 400.002
0.003
0.004
0.005
0.006
0.007
σ / Ω
-1cm
-1time / days
High conductivity
L. Persi, F. Croce and B. Scrosati; Electrochem. Comm. 4 (2002) 92
Li4Ti5O12 / GPE/ LiFePO4
lithium ion polymer cell
A 2V lithium-ion polymer battery!
P.Reale, S. Panero, B. Scrosati,J. Garche, M. Wohlfahrt-Mehrens, M.Wachtler,
J.Electrochem.Soc, 151 (2004) A2138
The Li4Ti5O12 / GPE/ LiFePO4 battery is characterized by reliability, long life an a high degree of safety.
However, this battery does not entirely meet the requirements for use in HEV where, in addition to safety and stability, also high rate is a key parameter.
Nanotechnology is a popular path to improve the rate capability of solid-state electrodes because of the reduced lithium diffusion length.Examples are the nano-structured nano-modified titanium oxide and the Ni-substituted manganesespinel.
A.S. Aricò, P. Bruce, B. Scrosati, J-M.Tarascon, W. van SchalkwijkNature Materials, 4 (2005) 366
Hydreothermalsynthesis:
TiO2 in NaOH
400°C 4h in air
Voltage profile
morphology
Brookite structure Pbca
TiO2 + xLi+ + xe- LixTiO2 1.5V
A.R.Armstrong, G.Armstrong, J.Canales, P.G.Bruce, Journal of Power Sources 146 (2005) 501A.R.Armstrong, G.Armstrong, J.Canales, P.G.Bruce, Electrochemical and Solid-State Letters, 9(2006) A139
a
b
c
xy
z
*In collaboration with Prof P.Bruceof University of St.Andrews, UK
New type of high rate anode: nanstructured TiO2 *
Theoretical specific capacity: 335 mAhg-1
20-40nm diameter
0 50 100 150 200 250
1,0
1,5
2,0
2,5
3,0
Vol
tage
/ V
Specific capacity / mAh/g
Wet chemistry synthesis:Li+, Ni2+ and Mn2+ nitrides
¯ in water800°C 16h in air
Voltage profile
morphology
Spinel structure P4332
LiNi0.5Mn1.5O4 Li0.5Ni0.5Mn1.5O4 + 0.5Li+ + 0.5e-
Li0.5Ni0.5Mn1.5O4 Ni0.5Mn1.5O4 + 0.5Li+ + 0.5e-. 4.5 V
ab
cx yz
MnO6 LiO412d 8cNiO64b
Ni-substituted LiNi0.5Mn1.5O4 spinel
P.Reale, S. Panero, B. Scrosati, J.Electrochem.Soc, 152 (2005) A1949
Theoretical specific capacity: 146 mAhg-1
0 50 100 150
3,0
3,5
4,0
4,5
5,0
Volta
ge /
V
Specific capacity / mAh/g
TiO2 / GPE / LiNi0.5Mn1.5O4
lithium ion polymer cell
A 3V Lithium-ion Polymer Battery!
G. Armstrong, A.R. Armstrong, P.G. Bruce, P. Reale, B. ScrosatiAdv. Mater., 18 (2006) 2597
Lithium ion polymer battery
Future research trends for HEV lithiumbattery R&D progress
Develop proper electrode nanostructures (rate).
Replace conventional anode and cathode with higher capacity electrode materials(energydensity).
Replace liquid with polymer electrolytes(safety).
Zero emission hydrogen fuel cell vehicles
HighPerformance
On-Board Power
EnvironmentallyClean
HighEfficiency
LowMaintenance
Reliability
Comfort(no vibration)Low Noise
Design Freedom
General Motor’s ELECTROVAN (1967)(with 400V, 160 kW UCC Alkaline FC System, liquid H2 und O2)
FC Cars TodayFC Cars Today
Source: Prof. Panik, DC
FuelFuel cellcell operationoperation
−+ +→ eHH 222
anodeOHeHO 22 22
21
→++ −+cathode
Energy renewal (hydrogen-economy)
Environmental control ( No-emission vehicles)
Major drawback: cost the catalyst (noble metals) the polymer electrolyte membrane (Nafion™ -type)
O2
H2O
H2
H+
Load
PEM
H2O
The most promising for electric vehicle applications the Polymer Electrolyte Membrane Fuel Cell, PEMFC
40 nmCarbonsupport
Catalyst particles
electrolyte
Gas-diffusion layer
Carbon-supportedcatalyst
O2
Three-phase zone
Impregnated ionomer
Fuel cell electrode structure
Courtesy of Professor E.Peled, Tel Aviv University
The cost of the electrode structure may be controlled by using high surface area substrates on which nanoscalecatalyst (Pt, Pt-Rh) particles may be dispersed.
Fuel cell electrode structure
Catalyst (Pt) particle
High surfacearea carbonsubstrate
With this approach, the precious metal loading may be reduced to very low levels, e.g few mg/cm2 and, with the new technologies, to 0,5 mg/cm2.
The goal of the car companies is to reach Pt loadings even lower than this limit.
Courtesy of Prof. Tom Zavodinski, Case Western University, Cleveland, USA
Successful R&D WorkPt-Catalyst Content
TimePt content [mg/cm²]
1997 4
2002 0.1
Today(labotatory results) 0.007
Common electrolytes for PEMFCs: perfluorosulphonic membranes, e.g., NAFION®
* CF2 CF2 n CF* CF2 *x
* CF2 CF m O
CF3
O-CF2-CF2-S H+
O3
Nanoscale phase separated microstructure as determined by SAXS (small angle X-ray scattering)
K. D. Kreuer, J. Membr. Sci., 185 (2001) 2
Common electrolyte membrane: NAFION®
* CF2 CF2 n CF* CF2 *x
* CF2 CF m O
CF3
O-CF2-CF2-S H+
O3
•high chemical stability• good conductivity• high cost• transport dependent on
hydration state• methanol crossover
Assisted protonic transport:Grotthuss mechanism
Methanol crossover
New types of proton membranes, having lower cost, higher thermal stability and higher selectivity than Nafion, are urgently required!
In lithium battery technology: lithium conducting membranes formed by trapping liquid solutions (e.g., a LiPF6-PC-EC solution ) in a suitable polymer matrix (e.g. a poly(vinylidene fluoride), PVdF matrix) Gel polymer electrolytes.
Extension to fuel cell technology: proton conducting membranes formed by trapping acid solutions (e.g., H2SO4 solutions ) in suitable composite (polymer + ceramic filler) matrices. Composite gel electrolyte membranes.
The main goal is to develop low-cost, low-methanol-permeability, temperature-resistant membranes for PEMFCs (DMFCs).
Strategy
0 5 10 15 20 25 3010-4
10-3
10-2
10-1
Con
duct
ivity
/ S
cm
-1
Time / d
Room Temperature
0 4 8 12 16 2010-3
10-2
10-1
T = 85 °CT = 60 °C
T = 25 °C
Con
duct
ivity
/ S
cm-1
Time / d
35 40 45 50 55 60 65 70 750.01
0.1
1
T = 80°C
T = 50°C
Con
duct
ivity
, S/c
m
Time, days
PVA/SiOx 6:1
T = 24°C
Conductivity
Time evolution of the conductivity of composite gel-type membranes at various temperatures.A) Al2O3-added PVdF-based membrane;B) Al2O3-added PVdF-PAN-based membrane; C) SiOx-added crosslinked PVA-based membrane.
A
B
C
M.A. Navarra, S. Panero, B.Scrosati, J.Electrochem.Soc., 2006
Ionic Liquids, ILs
Sodium chloride melts at 800 oC (Hot solution). Ionic liquids melts at much lower temp (Cool solution).
NaCl IL
Liquids composed of only ions!!
Moderate polarity
Thermal/chemical stability
Solubility (affinity) with several compounds
Low viscosity
Low melting point
Ion conductive materials for
Electrochemical devices
Solventsfor
Chemical reaction
Non-volatility
Non-flammability
Variation of ion structure
High ionic conductivity
Ionic liquids
They may have …
Appearance of proticIL-based membranes
T = 60 °C
T = 25 °C
A. Fernicola, S. Panero, B.Scrosati, M.Tamada, H. Ohno, PhysChemChemPhys, submitted
IL-based membranes have a significant ionic conductivity. The conductivity increases with temperature, reaching at 130 °C high and stable values.
Conductivity of IL 60%-PVdF 40% membrane at 130 °C.
0 2 4 6 8 101E-4
1E-3
0.01
Ar atmosphere
Con
duct
ivity
[Scm
-1]
Time [days]
T = 130 °C
MPdTFSI 60%
A. Fernicola, S. Panero, B.Scrosati, M.Tamada, H. Ohno, PhysChemChemPhys, submitted
Future research trends for fuel cell R&Dprogress
Develop ionis-liquid- based membranes (thermal stability).
Develop adequate electrode nanostructure (Pt loading).
Replace conventional Nafion-based membranes (Cost, crossover).
Search of alternate, not-precious metal catalysts (Cost).
Ecologic car Prospective
Hybrid car: in the market Controlled emission
Hydrogen car: in the market by 2010 (prevision) Zero emission?
Electric car: prototypesZero emission