1. Many renewable energy
sources – wind, solar – do
produce electricity irregularly
Batteries
Solution:
Renewable energy
sources +
effective Econversion and
storage
2. Many applications which
consumes energy cannot be
connected to the power grid,
e.g. cars
4%
1% 0.5%
Energy storage
Daniel Brandell
Department of Materials Chemistry
+ batteries + fuel cells
Batteries
Do we need batteries?
Conversion of chemical energy to electric energy
Non rechargeable – primary battery – galvanic cell
1.00E+07
Capacitors
Rechargeable – secondary battery – galvanic process (discharging),
then electorlysis (charging)
1.00E+06
Charging the battery
+
eV
1.00E+05
-
+
1.00E+04
V
Series1
1.00E+03
Electrochemical
Capacitors
1.00E+02
Batteries
1.00E+01
e-
Me Men+
Fuel
Cells
Men+
Me
Electrolyte
1.00E+00
0.01
0.1
1
10
100
1000
10000
Anode
Specific Energy [Wh/kg]
Cathode
Galvanic cell
Global battery production, USD
Pb.Acid
Pb.Acid
Smallrechar
Smallrechar
Primary
Primary
35 35
Billion USD
30 30
Primary
25 25
Billion USD
Specific Power [W/kg]
6%
20 20
15 15
Small rechargeable
Anode
Electrolysis
Demands for electrochemical applications
• The two electrode processes must have different
enough half-cell potentials, at least 1V
• The active cell components must only react when the
outer circuit is completed
• As high power and energy density as possible
• Cheap and accessible materials
• Environmentally friendly
10 10
5 5
Cathode
Lead-acid
• Fast electrode reactions
0 0
Total
Total
1
Strongly
reducing
The electrochemical reactivity series, V
Voltaic Pile
Series of standard electrode potentials
Li+ + e- ↔ Li
Na+ + e- ↔ Na
Mg2+ + 2e- ↔ Mg
-3.04
-2.71
-2.37
Al3+ + 3e- ↔ Al
2H2O + 2e- ↔ H2(g) + 2OHZn2+ +2e- ↔ Zn
Fe2+ +2e- ↔ Fe
-1.66
-0.83
-0.76
-0.45
Cd2+ + 2e- ↔ Cd
Ni2+ + 2e- ↔ Ni
Pb2+ + 2e- ↔ Pb
-0.40
-0.26
-0.13
2H+ + 2e- ↔ H2
0.00
Cu2+ + 2e- ↔ Cu
O2(g) + 2H2O + 4e- ↔ 4OHFe3+ + e- ↔ Fe2+
Ag+ + e- ↔ Ag
O2(g) + 4H+ + 4e- ↔ 2H2O
MnO4-(aq) + 8H+ + 5e- ↔ Mn2+ + 4H20
0.34
0.40
0.77
0.80
1.23
1.51
Volta from
Como in Italy
Voltaic pile, 1799
Strongly oxidizing
Where are we after 200 years?
Primary batteries
Flashlight battery (1866)
Alessandro Volta, 1801
(Cu/Zn)
1839
1859
1899
1973
1975
1979
Fuel cell
Pb battery
Ni-Cd
Li metal
Ni-MH
Li-polymer
Li-ion:
Sony 1990
Plastic Li-ion:
2000
Carbon rod
Electric current
Zn
Falls short of meeting clean
energy and HEV's demands in terms
of energy density, power rate and cost.
Breakthroughs are sorely needed…
Declining use today
Limitations:
• Can not be used for high-drain application (driving
electric motors)
• Available capacity falls sharply with increasing
discharge rate
• The shelf-life is not especially long (about two years)
• The optimum temperature range of operation is 10°C
to 40 °C
MnO2
NH4Cl, electrolyte
Leclanché
1839-1882
1,5 V
80-95 Wh/kg
Complicated
processes
Total reaction:
Zn(s) + 2 MnO2(s) + 2 NH4Cl(aq) →
ZnCl2(aq) + Mn2O3(s) + 2 NH3(aq) + H2O
Why do batteries sometimes leak?
The pH in vicinity of the Zn-electrode decreases due
to hydrolysis of the Zn2+ ion via reactions such as:
Zn2+ + H2O → Zn(OH)+ + H+
The resulting fall in pH leads to enhanced chemical
corrosion with liberation of hydrogen.
As the internal pressure in the cell rises, the seals
ultimately leak and force electrolyte out of the cell
ZnCl2 is one solution instead of NH4Cl
2
Alkaline batteries
Invented in the 1940’s, the difference to the
”flashlight battery” is the electrolyte, KOH
5-8 times as long life as the flashlight battery.
There are some on the market which contain
toxic heavy metals
We use ~40 million alkaline and ~30 million Zn-MnO2
batteries per year in Sweden.
The Pacemaker – a Swedish innovation from 1958
Consists of two parts:
Pulse generator, which produce the pulses which
stimulates the heart.
Wires who sends the pulses to the heart.
The wires also send signals back from the heart. By
”reading” the signals, the pulsgenerator can feel the
activity of the heart and send the right impulses at the
right time.
The pulse generator contain the battery and the
electronic equipment.
The pacemaker
A typical pacemaker battery has a volume of 6 ml and a mass of 22 g.
Single-Chamber Pacemakers
Dual-Chamber Pacemakers
Zink-air battery
A hybrid between a battery and a fuel cell
Cathode:
Catalyst
needed!
O2 +H2O + 2e- → HO2- + OHHO2-
+ H2O +
2e-
→
3OH-
Anode:
OCV=1.4V
Zn → Zn2+ + 2eUsed for hearing aids
Energy density for some of the most
common secondary batteries
The Lead-acid accumulator
Energy/weight 30-40 Wh/kg
Energy/size 60-75 Wh/l
Power/weight 180 W/kg
Charge/discharge efficiency 70%-92%
Self-discharge 3%-20%/month
Gaston Planté 1859
Lifetime 500-800 cycles
Nominal Cell Voltage 2.0 V
3
The Lead-acid accumulator
Lead grid
0,5×1,0 cm
When the lead-acid accumulator is in use
A paste of PbO is pressed
into the lead grid
PbO2 + 4 H+ + 2e- + SO42- → PbSO4 + 2 H2O E°=0.356V
Pb + SO42- → PbSO4 + 2 e-
The elektrodes are
forming a battery
with 6M H2SO4 as
electrolyte through
the processes:
PbO +
+ H2O
2e-
+
2H+
→ Pb
PbO + H2O → PbO2 +
2H+ + 2e-
Total reaction:
PbO2 + Pb + 2 SO42- + 4 H+ → 2 PbSO4 + 2 H2O
or
PbO2 + Pb + 2 H2SO4 → 2 PbSO4 + 2 H2O
ΔE=2V
Lead (Pb)
Why?
•
•
•
•
70
60
50
40
%
%
30
20
10
0
Batteries
Batteries
E°=1.685 V
Alloys, etc.
Chemicals Semi-finished gods & cab
Alloys
ChemiSemi-finished
Pb cals
etc.
goods and cables
The nickel-cadmium battery
Price
Safety
Temperature range
“its ability to supply high surge currents
means that the cells maintain a relatively
large power-to-weight ratio”.
Reactions in the Ni-Cd battery
Cd(OH)2 + 2e- → Cd + 2OHNi(OH)2 + OH- → NiOOH + H2O + eCd
Ni(OH)2
→ charge
← discharge
Risk for overcharging:
4OH- → O2 + H2O + 2eHeat formation at the anode
Electrolyte: KOH
4
Nickel metal hydrid battery
Cd
Works as Ni-Cd,
but the anode is a
substance that
can store H2:
100
80
AB5, where A and
B are metals, e.g.
LaNi5. Other are of
type AB2, also with
A and B being
different metals
%
60
%
40
20
0
NiOOH
Batteries
Batteries
Cd
1,5 V
Fast charging
Expensive
Good when high
effect is needed
Furtilisers
Pigments
Stabilizers
Electrolyte: KOH
The sodium-sulphur battery and
the Zebra battery
Reactions
Alloy + H2O + e- → Alloy[H] + OHNi(OH)2 + OH- → NiOOH + H2O + e-
High temperature batteries based on sodium (Na) as anode
and which work at 250-300 °C
→ charging
← discharging
Overcharging:
4OH- → O2 + H2O + 2egenerates heat
Chemistry in the sodium-based
batteries
2Na + 5S = Na2S5
V= + 2.076 V
2xNa + (5-x)Na2S5 = 5Na2S5-x
V= + 1.78 V
NiCl2 + Na = Ni + 2NaCl
V= + 2.58V
FeCl2 + 2Na = Fe + 2NaCl
V= +2.35 V
2NaAlCl4 + Ni = 2Na + 2AlCl3 + NiCl2
Both have a ceramic electrolyte, β-alumina
High temperature to get high ion conductivity in the
electrolyte
The Zebra battery
Advantages
High energy density
(5 times higher than Lead
acid)
Large cells (up to 500Ah)
possible
Cycle life better than 1000
cycles
Tolerant of short circuits
Safer than Sodium Sulfur cells
Low cost materials
Shortcomings
Suitable for large capacity
batteries only (> 20KWh)
Limited range of available sizes
and capacities.
Molten sodium electrode
High operating temperature.
Preheating needed to get battery
up to the 270°C operating
temperature. (Up to 24 hours from
cold)
Uses 14% of its own capacity per
day to maintain temperature when
not in use.
Thermal management needed
5
Lithium-ion battery
Lithium polymer battery
Reversed process when charging → Intercallation
materials
The rechargeable lithium battery
e-
e-
Lithium
polymer-battery
Why lithium?
In the electrochemical reactivity series,
V6O13 V2O5
lithium have E° = -3.04 V
Li+ + e- ↔ Li (s)
ELECTROLYTE
LiCoO2
LiMn2O4
LiFePO4
Lithium ionbattery (graphite)
And Li+ have short ionic radius, 0.76 Å
And Li have also low density, 0.53 g/cm3
LiFePO4
Lithium alloy
LiFeSiO4
6
5
Voltage versus Li
compound
unstable in air
electrolyte oxidizes
Electrode Material Selection
LiNiVO4
LixV2O5
LixV6O13
LixMn2O4
LixMnO2
LixTiS2
2
3
LiAl
0
Li-Metal
LixCoke
Li Graphite
1
0
Orthosilicates:
Li2FeSiO4 ->LiFeSiO4, ~2.8V, 140
mAh/g
Olivines:
LiFePO4 ->FePO4, ~3.5V, 160
mAh/g
2
LixWO2
Spinels:
LiMn2O4->Mn2O4: ~3V or ~4.0V, 120 mAh/g
Instabilities!
Solution
doping!
LiNi0.5Mn0.5O2:
~4.0V, 200 mAh/g
4
LixMoO2
1
Layered:
LiCoO2->Li0.5CoO2: ~3.9V, 140 mAh/g
5
LixNiO2
LixCoO2
4
3
6
LiF
Comparison of Different Cathodes Materials
Electrochemical
potential of some
Li-intercalation
compounds
versus Li metal
Poor conductivity!
Solution:
doping, coating,
nanosize
6
Polymer electrolytes
Satefy problems
Undesired reactions between the battery components and liquid
organic electrolyte – not strange at high or low potentials –
triggered by unpredictable events such as:
More safe, but less mass transport
• Short-circuits
To increase ion conductivity:
• Local overheating
• Plasticizers
• Nanoparticles
• Gas formation (volatile)
• Change polymer: PPO, polyimides
⇒ Exothermic reaction of the electrolyte with the electrode
materials.
• Modify PEO: cross-links, side-chains
• Ionic Liquids
Lithium goes along a poly(ethylene oxide)
chain
Thermal runaway!!
In cars: larger
volumes…
-(CH2-CH2-O-)n
The Li-ion battery – a success story!
Novel nano-materials
Increasing size
Energy density
Safety
Lifetime/cost
Power density
210Wh/kg
Safety
Power/Energy density
Lifetime cost
625Wh/l
Lifetime cost
Scalability
Power/Energy density
Safety
HEVs – a temporary solution?
Energy Management
+
Battery
Energy
Energy supply to
make up for shortage
Motor Assist
EV Drive
Storage of
excess energy
Recovery of
braking energy
Engine turns off
Time
Engine output energy with
maximum efficiency
-
7
Larger batteries will also play an important role . . .
From HEVs to P-HEVs !
Sustainable Energy System:
Fuel Economy
Power
gen.
Current HEVs
e.g.,
PRIUS(Toyota)
INSIGHT(Honda)
HT
HTA (20000V)
BT(230V)
HT
Next Generation P-HEVs
LT
50 –150 KVA
1
Central
battery storage
HEV marketability
LT
(Centralized)
(Decentralized)
2
Solpaneler
Local
battery storage
+ - + -+ - + -+ -+ -
ＩＣＥ
Vehicles
LT
box
+-+- +-++- +-
Fun to Drive
EV from Uppsala!
Centralized/Decentralized
3
Gridconnected
Solar panels
+ - + -+ - + -+ -+ -
Off-grid
4
a ”green” EV !!!
Other trends/research areas:
2. Li-batteries from biomaterials
1. The role of nano: LiFePO4 and Li2FeSiO4 cathodes, Si
anodes
O
LiO
OLi
LiO
OLi
O
μm
LiFePO4
Lithiated
Terahydroquinone
Dilithium
dirhodizonate
Poizot et al. Nature, 407, 496-499 (2000).
Si
PVC +PO
c
4-6 h 900°C
(N2)
Carbon
nano painting
b
a
Li2FeSiO4
Si
3. Novel Li-battery chemistries: Li-S, Li-air
4. 3D-microbatteries
2Li+ + O2 + 2e- → Li2O2
For MEMS, biomedical
micro-machines:
Same foot-print area:
1000mAh/g
Nano α−MnO
2D – thin film
Short Li transport path
Ê high rate capability (power)
2020
Future
Na-ion
chemistry
2015
Li-S
2007
Organic
cathodes
A123
2005
Nano-cathodes
Sony
1995
Sony
Sony
1990
Future
??????
Specific power increases
Li-air
Energy density
2
2D – thick film
Large amount of active material
high capacity (energy density)
goal
2D
thin film
2D – thick film
Future
Specific energy increases
8