1. Materials for Energy Storage
Yang-Kook Sun
Energy Storage and Conversion Materials Lab.
(FTC 1017) (02) , (017)

2. Grade Items Score Mild-term 100 Final-term Attendance 30 Presentation합계
330

3. - Text 1) LITHIUM BATTERIES Science and Technology, G. -A. Nazri and G
- Text 1) LITHIUM BATTERIES Science and Technology, G.-A. Nazri and G. Pistoia Eds. Kluwer Academic Pub., ) Lithium Secondary Batteries, 박정기, 홍릉과학출판사, ) J. of Electrochem. Soc.: 4) J. of Power Sources: 5) Electrochimica Acta: 6) Nature Materials: 7) Energy & Environmental Science: 8) J. of Amer. Chem. Soc.: 9) Chem. Mater.: 10) J. of Phy. Chem. C: 11) Adv. Mater.: 12) J. Mater. Chem.: 13) Angewandte Chemie: ) Adv. Ener. Mater.: 15) Electrochemistry Communications: 16) Nat. Commun.: 18) Nat. Chem.: 19) Nano Energ.:

4. 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 Mn+ + ne-
Cathode : X + ne Xn-
Overall : M + X Mn+ + Xn-
Load
Anode M
Cathode X
Separator
Electrolyte e
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
Nm = 𝐼𝑡 𝑛𝑁𝐴 𝑒 = 𝐼𝑡 𝑛𝐹 where n; # of electrons given up or
accepted by M or X
Q = It = nFNm : theoretical capacity
Figure 1. Schematic of an electrochemical cell

5. Electrochemical Concepts
1F (faraday) = # of avogadro × charge of one electron
= × ×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.
Eo 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
𝑬 = 𝑬 𝜽 − 𝑹𝑻 𝝂𝑭 𝒍𝒏 𝑎𝑀 𝑛 𝑎𝑋𝑛 𝑎𝑀 𝑎𝑋
𝑬 = 𝑬 𝜽 − 𝟎.𝟎𝟓𝟗𝟏 𝒏 𝒍𝒏 𝑎𝑀 𝑛 𝑎𝑋𝑛 𝑎𝑀 𝑎𝑋 + - - +

6. 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
Figure 2. Variation of cell voltage with operating current illustrating polarization losses

7. 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

8. History of Batteries

9. Mg + 2MnO2 + H2O → Mn2O3 + Mg(OH)2
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
Mg + 2MnO2 + H2O → Mn2O3 + Mg(OH)2
2.8
271
Alkaline MnO2
Zn + 2MnO2 → ZnO + MnO3
1.5
Mercury
HgO
Zn + HgO → ZnO + Hg
1.34
190
Zinc-air O2
Zn + 0.5O2 → ZnO
1.65
658
Li-SO2 Li
SO2
2Li + 2SO2 → Li2S2O4
3.1
379
Li-MnO2
Li + MnO2 → LiMnO2
286
a Based only on active cathode and anode materials

10. History of Batteries 1990s~ 1980s~ 1970s~ 1899 1859
· Lithium-ion Battery (3.6V)
1980s~
· Ni-MH Battery (1.2V)
1970s~
Ni-Cd, 1973
· 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

11. Cd + 2NiOOH + 2H2O → 2Ni(OH)2 + Cd(OH)2
Table 2. Major Secondary Battery Systems
Battery
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
H2 + 2NiOOH → 2Ni(OH)2
1.5
289
Nickel-metal hydride MH
MH + NiOOH → M + Ni(OH)2
206
Lithium-ion Li
Li0.5CoO2
0.5Li + Li0.5CoO2 → LiCoO2
3.7
137
a Based only on active cathode and anode materials.

12. Reactions in the solid state:
Gaston Planté and the lead-acid battery (1859):
The first rechargeable system
PbSO4
4 H+ Pb
PbO2
SO42-
H2SO4 / H2O v + _
I/A
H2O-
PbO2(s) + 4H+ + SO e-
    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; Wh/l)
Reduced cyclability and calendar life, weak in temperature
Reactions in the solid state:
● Breaking of chemical bonds at both electrodes 12

13. W. Jungner (1909): The Ni-Cd batteries and its
its derivatives Ni-Fe, Ni-Zn, and Ni-H2
Cd: 1.2 V
Fe; 1.4 V
Zn: 1.7 V
H2: 1.3 V Cd
Long calendar life
High power
Good cycling behaviour
Waldemat Junger has invented the Ni-Cd battery in 1899 and try to replace Cd by Fe, therefore here is found thath there has been too much H2 gasing so he decided to abandon (although he had several patents). it and Edison took over in 1901 wit
Performances
45-60 Wh/kg
170 W/kg
2000 cycles
Weak specific energy
Important self-discharge
Cadmium toxicity

14. 1975: the Nickel-Metal hydride battery: Two insertion reactions
"LaNi5H6"
+ 6H+
+ 6e-
"LaNi5"
High Volume energy (310 Wh/L)
Good cyclability
High power rate
Cost of materials
Energy density (80Wh/kg)
1997, Toyota Prius
Performances
80 Wh/kg
W/kg
1000 cycles

15. Large energy densities
How to increase the energy density of rechargeable
Batteries ??? From H+ to Li+
ENERGY
Energy density (Wh/kg) =
Capacity (Ah/kg) x V (volts)
Requires aqueous media
Limited to 1.2 V
(Water stability)
Reacts with water
Organic electrolytes
Lightest metal (6.9 g)
Most reducing metal
- 3.04V vs. ENH
Large energy densities
ENERGY
CAPACITY
(Volts)
0.8
0.4
1.2
1.4
1.0
0.2
0.6
Number of e- exchanged
POTENTIAL
ENERGY

16. Comparison of Energy Density
Why Li-ion ?
Comparison of Energy Density
Lead Acid
Ni-Cd
Ni-MH
LiB
LiPB

17. Market for LIB

18. Why Li-ion ? Market trend: Mobile IT → EV or ESS LIBs Market for Auto
Market for LIBs
LIBs Market for Auto

19. Development of Ni-rich cathode is indispensable !!
LIBs Market for automobile
The market will exponentially increase in the future.
In 2019, based on the number of car, BEV market is only 16%. However, based on energy, BEV market will be 57%.
333 NCM widely used in Evs with driving range of around 100 miles, to increase driving range, we should develop high capacity Ni-rich cathode materials.
Development of Ni-rich cathode is indispensable !!

20. LIB Energy Density History
-. Higher voltage cut-off
-. Metal alloy NE
Map of energy density for cylindrical LIB (18650)
98 → 185 Wh/kg
220 → 620 Wh/L ?
The 1st LIB was introduced
in the market by SONY (1991)
For last 20yrs, energy density
of LIB has been increased only 2~3times
Changing the negative material from H/G to Graphite
Improving the high voltage
stability of positive materials
Optimizing cell design to
maximize the packing density
- 3 -

21. Chem. Energy Electrical Energy
Principle of Lithium Batteries
charge e-
Chem. Energy Electrical Energy
Charge
Discharge
charger
e- discharge
cathode
anode
discharge Li charge
Oxygen Metal Atom Lithium Carbon
- 16 -

22. Lithium-Ion Battery Charge
Electrolyte
Cu Current
Collector
AL Current
Collector
Graphite
LiMO2
SEI
SEI

23. Lithium-Ion Battery Discharge
Electrolyte
Cu Current
Collector
AL Current
Collector
Graphite
LiMO2
SEI
SEI

24. Cost analysis of materials and battery
Material cost
Battery cost
Cathode
Separator
Anode
Electrolyte
Case
Others
Material
Depreciation
Labor
Ownership
Profit

25. Four Key Materials for Li-ion Batteries
Requirement
Cathode
∙ 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
Electrolyte
∙ Organic Solvent
(EC, EMC, DME, DEC, etc.)
∙ Less Flammable
∙ Li Salt
∙ Low Cost
(LiPF6, LiBF4, LiBOB, etc.)

26. Electrochemical Concepts
Eoc
Eop
Current / A
Cell Voltage / V
Ohmic polarization
Activation polarization
Concentration polarization