Materials for Energy Storage
Yang-Kook Sun
Energy Storage and Conversion
Materials Lab.
http://energy.ce.to/
(FTC 1017)
(02)2220-0524, (017)335-4074
[email protected]
• Grade
Items
Score
Mild-term
100
Final-term
100
Attendance
30
Presentation
100
합계
330
Energy Storage & Conversion Material Laboratory
- Text
1) LITHIUM BATTERIES Science and Technology, G.-A. Nazri and G. Pistoia Eds.
Kluwer Academic Pub., 2004
2) Lithium Secondary Batteries, 박정기, 홍릉과학출판사, 2010
3) J. of Electrochem. Soc.: http://www.ecsdl.org/JES
4) J. of Power Sources: http://www.sciencedirect.com/science/journal/03787753
5) Electrochimica Acta: http://www.sciencedirect.com/science/journal/00134686
6) Nature Materials: http://www.nature.com/nmat/index.html
7) Energy & Environmental Science: http://pubs.rsc.org/en/journals/journalissues/ee
8) J. of Amer. Chem. Soc.: http://pubs.acs.org/journal/jacsat
9) Chem. Mater.: http://pubs.acs.org/journal/cmatex
10) J. of Phy. Chem. C: http://pubs.acs.org/journal/jpccck
11) Adv. Mater.: http://onlinelibrary.wiley.com/doi/10.1002/adma.v20:21/issuetoc
12) J. Mater. Chem.: http://pubs.rsc.org/en/journals/journalissues/jm
13) Angewandte Chemie: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)15213773
14) Adv. Ener. Mater.: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1614-6840
15) Electrochemistry Communications:
http://www.sciencedirect.com/science/journal/13882481
16) Nat. Commun.: http://www.nature.com/ncomms/index.html
18) Nat. Chem.: http://www.nature.com/nchem/index.html
19) Nano Energ.: http://www.sciencedirect.com/science/journal/22112855
Electrochemical Concepts
 A battery is an electrochemical cell that converts the chemical energy of a
reaction directly into electrical energy
Chemical
Energy
Electrical
Energy
Electrochemical cells
Anode : M
Cathode : X + ne-
Load
Electrolyte
Cathode
X
Separator
XnMn+ + Xn-
Overall : M + X
e
e
Anode
M
Mn+ + ne-
When a current of I amperes flows in the circuit for a time
of t seconds, then the amount of charge Q transferred
across any interface in the cell is equal to It coulombs.
- Number of moles Nm of the reactants M or X
consumed by the passage of It coulombs is given by
Electrolyte
Figure 1. Schematic of an electrochemical cell
Nm =
Q = It =
𝐼𝑡
𝑛𝑁𝐴 𝑒
=
𝐼𝑡
𝑛𝐹
where n; # of electrons given up or
accepted by M or X
nFNm : theoretical capacity
Energy Storage & Conversion Material Laboratory
Electrochemical Concepts
1F (faraday) = # of avogadro × charge of one electron
= 6.023 × 1023 × 1.6 × 10−19 C = 96485 C /equivalent = 26.8 Ah/equivalent
Thermodynamics of Electrochemical Cells
-
The driving force for an electrochemical cell to deliver electrical energy to an external circuit is
the decrease in the standard free energy ∆Go of the cell reaction.
Galvanic cell : ∆Go < 0 , Spontaneous reaction
∆Go = -nFEo, where N and F are, respectively, the # of electrons involved in the reaction
-
-
and the Faraday constant.
is the difference between electrode potential of the cathode and anode and the equilibrium
potential when all of the cell component are in their standard states; a positive value of Eo
means that the cell reaction occurs spontaneously.
Nernst equation at standard state
Eo
𝑬 =
𝑹𝑻
𝜽
𝑬 −
𝝂𝑭
𝑎𝑀 𝑛+𝑎𝑋𝑛𝒍𝒏
𝑎𝑀 𝑎𝑋
𝟎. 𝟎𝟓𝟗𝟏 𝑎𝑀 𝑛+𝑎𝑋𝑛𝑬 =𝑬 −
𝒍𝒏
𝒏
𝑎𝑀 𝑎𝑋
𝜽
Energy Storage & Conversion Material Laboratory
Electrochemical Concepts
Polarization Losses in Electrochemical Cells
-
When a current I is passed through the cell, part of energy is lost as waste heat due to
polarization losses in the cell (three types); 1) activation polarization, 2) concentration
polarization, and 3) ohmic polarization.
Activation polarization is related to the kinetics of electrode reactions
Concentration polarization is related to the concentration differences of the reactants and
products at the electrode surfaces and in the bulk as a result of mass transfer
Ohmic polarization, usually referred to as internal IR drop, is related to the internal
impedance of the cell, which is sum of the ionic resistance of electrolyte and the electronic
resistance of the electrodes
Eoc
Cell Voltage / V
-
Ohmic polarization
Activation polarization
Eop
Concentration polarization
Current / A
Figure 2. Variation of cell voltage with operating current illustrating polarization losses
Energy Storage & Conversion Material Laboratory
OPERATING PARAMETERS in Batteries
Capacity, Ah, is the total quantity of charge that the battery may
deliver in discharge.
Gravimetric Specific capacity, Ah/g, is the total quantity of
charge that the battery may deliver in discharge per weight.
Volumetric Capacity density, Ah/cm3, is the total quantity of charge
that the battery may deliver in discharge per volume.
Gravimetric Energy Density, Wh/kg, is the energy that the battery
can deliver per weight.
Volumetric Energy density Wh/cm3, is energy that the battery can
deliver per volume.
- The practical values, that include total weight or volume (electrodes,
electrolyte, case, current collector, separators, etc) are usually 1/4 of
the theoretical ones. For instance in the case of the lead acid battery,
the theoretical value is 171 Wh/ kg while the practical value
decreases to about 40 Wh/kg
Energy Storage & Conversion Material Laboratory
History of Batteries
1834
FARADAY
Faraday law
Energy Storage & Conversion Material Laboratory
Table 1. Major Primary Battery systems
Cell Voltage
Capacity
Battery
Anode
Cathode
Cell Reaction
(V)
(Ah/Kg)a
Leclanche
Zn
MnO2
Zn + 2MnO2 → ZnO∙Mn2O3
1.6
224
Magnesium
Mg
MnO2
Mg + 2MnO2 + H2O → Mn2O3 + Mg(OH)2
2.8
271
Alkaline MnO2
Zn
MnO2
Zn + 2MnO2 → ZnO + MnO3
1.5
224
Mercury
Zn
HgO
Zn + HgO → ZnO + Hg
1.34
190
Zinc-air
Zn
O2
Zn + 0.5O2 → ZnO
1.65
658
Li-SO2
Li
SO2
2Li + 2SO2 → Li2S2O4
3.1
379
Li-MnO2
Li
MnO2
Li + MnO2 → LiMnO2
3.1
286
a
Based only on active cathode and anode materials
Energy Storage & Conversion Material Laboratory
History of Batteries
1990s~
1980s~
1970s~
Ni-Cd, 1973
· Lithium-ion Battery (3.6V)
· Ni-MH Battery (1.2V)
· Lithium Battery
· Early 1970s: Nickel hydrogen battery
· 1955: Common alkaline battery
· 1903: Ni-Fe battery (EDISON)
1899
· Ni-Cd Battery (1.2V)
· 1887: Zinc-carbon cell – the first dry cell
· 1866: Leclanche Cell
· 1860s: Gravity Cell
1859
· Lead-acid Cell: the first rechargeable battery (1.2V)
· 1844:
Grove Cell
· 1836: Daniell Cell
· 1800: Voltaic Pile
Table 2. Major Secondary Battery Systems
Anode
Cathode
Cell Reaction
Cell Voltage
(V)
Capacity
(Ah/kg)a
Lend-acid
Pb
PbO2
Pb + PbO2 + 2H2SO4 → 2PbSO4 + 2H2O
2.1
120
Nickel-cadmium
Cd
NiOOH
Cd + 2NiOOH + 2H2O → 2Ni(OH)2 + Cd(OH)2
1.35
181
Nickel-hydrogen
H2
NiOOH
H2 + 2NiOOH → 2Ni(OH)2
1.5
289
Nickel-metal hydride
MH
NiOOH
MH + NiOOH → M + Ni(OH)2
1.35
206
Li
Li0.5CoO2
0.5Li + Li0.5CoO2 → LiCoO2
3.7
137
Battery
Lithium-ion
a
Based only on active cathode and anode materials.
Energy Storage & Conversion Material Laboratory
Gaston Planté and the lead-acid battery (1859):
The first rechargeable system
+
v
I/A
PbO2
_
SO42-
Pb
4 H+
PbSO4
H2 O -
SO42-
PbSO4
H2SO4 / H2O
PbO2(s) + 4H+ + SO42- + 2e PbSO4(s) + 2H2O
DE = 2,0 V
Pb(s) + SO42 PbSO4 + 2e-
● Usable batteries for thermal vehicles
● Industrial batteries (network support, heavy traction)
Its cost (100 €/kWh)
Low energy and specific power (25-35 Wh/Kg; 60-120Wh/l)
Reduced cyclability and calendar life, weak in temperature
Reactions in the solid state:
● Breaking of chemical bonds at both electrodes
Energy Storage & Conversion Material Laboratory
W. Jungner (1909): The Ni-Cd batteries and its
its derivatives Ni-Fe, Ni-Zn, and Ni-H2
v
+
Ni
Ni(OH)2
Ni
Ni
_
DE = 1,2 V
OH
OH
OH
OH
Cd
OH
OH
Cd
OH
Cd
OH
OH
OH
OH
OH
OH
-
H+
H+
(
NiOOH
OH
Ni lamellaire)
(Hydroxyde
OH
O
OH
Ni
OH
O
OH
Ni
OH
O
)
H 2O
Cd
Cd
Aqueous electrolyte (KOH)
Ni(OH)2(s) + OH-  NiOOH(s) + H2O + e-
Long calendar life
High power
Good cycling behaviour
Weak specific energy
Important self-discharge
Cadmium toxicity
Cd(OH)2
Cd(OH)2(s) + 2e-

Cd: 1.2 V
Cd Fe; 1.4 V
Zn: 1.7 V
H2: 1.3 V
Cd(s) + 2OH-
Performances
45-60 Wh/kg
170 W/kg
2000 cycles
90 km/h,
90 km d’autonomie
Energy Storage & Conversion Material Laboratory
1975: the Nickel-Metal hydride battery:
Two insertion reactions
v
+
Ni(OH)2
DE = 1,3 V
OH
OH
OH
Ni
OH
OH
Ni
OH
Ni
NiOOH
H
H
H
OHH+
OH
Ni lamellaire)
(Hydroxyde
OH
O
OH
Ni
OH
O
OH
Ni
OH
O
_
H+
H 2O
H
H
Aqueous electrolyte (KOH)
Ni(OH)2(s) + OH-  NiOOH(s) + H2O + e-
High Volume energy (310 Wh/L)
Good cyclability
High power rate
Cost of materials
Energy density (80Wh/kg)
MHx
"LaNi5H6"
+ 6H+
+ 6e-
H
M
"LaNi5"
M + xH2O + xe-  MHx + xOH-
Performances
80 Wh/kg
200-1350 W/kg
1000 cycles
1997, Toyota Prius
Energy Storage & Conversion Material Laboratory
How to increase the energy density of rechargeable
Batteries ??? From H+ to Li+
Energy density (Wh/kg)
=
Capacity (Ah/kg) x V (volts)
3
1
1.0079
6.941
0.98
2.2
14.5
180.5
0.534
0.089
Li
H
1s212s1
Lithium
Hydrogen
Requires aqueous media
Limited to 1.2 V
(Water stability)
1.0
(Volts)
POTENTIAL
1.4
1.2
0.8
0.6
0.4
ENERGY
ENERGY
ENERG
Y
0.2
0
Lightest metal (6.9 g)
3
0.98
180.5
0.534
6.941
Li
1s
1s22s11
Lithium
Number of e- exchanged
CAPACITY
Most reducing metal
- 3.04V vs. ENH
Large energy densities
Reacts with water
Organic electrolytes
Energy Storage & Conversion Material Laboratory
Why Li-ion ?
Comparison of Energy Density
(Wh/kg)
300
LiB
LiPB
200
Ni-MH
Ni-Cd
100
Lead
Acid
0
0
100
200
300
400
500
600
700
(Wh/L)
Energy Storage & Conversion Material Laboratory
Market for LIB
Energy Storage & Conversion Material Laboratory
Why Li-ion ?
Market trend: Mobile IT → EV or ESS
Market for LIBs
LIBs Market for Auto
Energy Storage & Conversion Material Laboratory
LIBs Market for automobile
Km – driving range
GWh
HEV-NiMH
HEV-Li
PHEV
500
450
400
350
300
250
200
150
100
50
-
BEV
100
90
80
 90% market of PHEV+BEV
70
60
50
40
KWh – battery
100
90
80
70
60
50
40
30
20
10
-
Range(Km)
Capa.(KWh)
30
20
Tesla
10
Based on the number of car
HEVNiMH
36%
Based on Energy
HEV-Li
4%
BEV
16%
HEV-Li
31%
PHEV
17%
PHEV
33%
Source : B3 Report
HEV-NiMH
6%
BEV
57%
BMW
GM
Nissan
Item
NCM1/3
Ni-rich1)
Capacity (mAh/g)
155~165
190~200
Electrode Density
3.0~3.3
3.2~3.6
Voltage (V)
3.65
3.6
Energy (Wh/cc)
1.99
2.72
Cycle
Excellent
middle
Power
Good
Good
(g/cc)
1) Ni-rich: Ni ≥80% NCA or NCM
Development of Ni-rich cathode is
indispensable !!
Energy Storage & Conversion Material Laboratory
LIB Energy Density History
Gravimetric Energy Density (Wh/kg)
Map of energy density for cylindrical LIB (18650)
2007
190
?
2008
The 1st LIB was introduced
in the market by SONY (1991)
2005
2003
2002
2001
170
2000
Typ.3000mAh Typ.3600mAh
Typ.2800mAh
Typ.2600mAh
Typ.2400mAh
Typ.2200mAh
Typ.2000mAh
1998
Typ.1900mAh
150
For last 20yrs, energy density
of LIB has been increased
only 2~3times
-. Higher voltage cut-off
-. Metal alloy NE
Typ.1700mAh
Changing
the
negative
material from H/G to Graphite
1996
130
1995
1994
Typ.1420mAh
98 → 185 Wh/kg
220 → 620 Wh/L
Typ.1370mAh
110
Improving the high voltage
stability of positive materials
Typ.1250mAh
Optimizing cell design to
maximize the packing density
Typ.860mAh (1st LIB by SONY)
90
200
300
400
500
600
700
800
900
Volumetric Energy Density(Wh/l)
-3-
Energy Storage & Conversion Material Laboratory
Principle of Lithium Batteries
Discharge
Chem. Energy
Electrical Energy
Charge
charge e-
charger
•
e- discharge
cathode
discharge
anode
Li+
charge
Oxygen Metal Atom Lithium Carbon
- 16 -
Energy Storage & Conversion Material Laboratory
Charge
Lithium-Ion Battery
Electrolyte
Cu
Current
AL
Current
Collector
Collector
Graphite
LiMO2
SEI
SEI
Energy Storage & Conversion Material Laboratory
Discharge
Lithium-Ion Battery
Electrolyte
Cu
Current
AL
Current
Collector
Collector
Graphite
LiMO2
SEI
SEI
Energy Storage & Conversion Material Laboratory
Cost analysis of materials and battery
Profit
Others
Ownership
Labor
Depreciation
Others
Case
Electrolyte
Anode
Separator
Material
Battery cost
Cathode
Material cost
Energy Storage & Conversion Material Laboratory
Four Key Materials for Li-ion Batteries
Materials
Cathode
Requirement
∙ LiCoO2
∙ High Energy
∙ LiNiCoMnO2
∙ Low Cost
∙ LiFePO4
∙ Safety
∙ Li1+xNiCoMnO2
Anode
∙ Graphite
∙ High Energy
∙ Hard carbon / Soft carbon
∙ Low Cost
∙ Li4Ti5O12
∙ Fast Charge
∙ Si, Sn, etc
Separator
∙ PE / PP
∙ Low Thermal Shrinkage
∙ Nonwoven
∙ High Mechanical Strength
∙ Ceramic Coated
∙ Low Cost
∙ Organic Solvent
Electrolyte
(EC, EMC, DME, DEC, etc.)
∙ Li Salt
∙ Less Flammable
∙ Low Cost
(LiPF6, LiBF4, LiBOB, etc.)
Energy Storage & Conversion Material Laboratory
Electrochemical Concepts
Cell Voltage / V
Eoc
Ohmic polarization
Activation polarization
Eop
Concentration polarization
Current / A
Energy Storage & Conversion Material Laboratory