1. DESIGN OF NEW CATHODE
MATERIALS FOR SECONDARY
LITHIUM BATTERIES
E. Sivanagi Reddy

2. Index
 Introduction
 Battery – Timeline
 Applications of batteries
 Secondary Lithium ion battery
 Structure of battery
 Cathode materials
 Advances in cathode materials
 Promising cathode materials
 conclusion

3. Introduction
 Beginning with the ‘frog-leg experiment’ by
Galvani (1786), followed by the
demonstrations of Volta pile by Volta (1792)
and lead-acid accumulator by Plante
(1859), several battery chemistries have been
developed and realized commercially

4. Battery
 A battery is a transducer that converts
chemical energy into electrical energy and
vice versa.
 It contains
An anode - source
A cathode - sink
An electrolyte - the separation of ionic
transport and electronic transport

5. Timeline for the major events in the history of batteries

6. Applications of batteries

7. Types of batteries
 Primary batteries are disposable because their
electrochemical reaction cannot be reversed.
ΔG negative (irreversible)
 Secondary batteries are rechargeable, because their
electrochemical reaction can be reversed by
applying a certain voltage to the battery in the
opposite direction of the discharge.
ΔG negative, discharge
ΔG positive, charge

8. Comparison of the volumetric and
gravimetric energy density with other
batteries

10. Lithium ion batteries
 The name of “lithium ion battery” was
given by T. Nagaura and K. Tozawa
 The concept of “lithium ion battery”
was firstly introduced by Asahi Kasei
Co. Ltd
 Lithium ion batteries were first proposed
by M. S. Whittingham in the 1970’s.
Whittingham used TiS2 as the cathode
and Lithium metal as the anode.

11. Lithium ion secondary
Batteries
 The lithium ion battery (LIB) system has been
most successful in recent development of battery.
 Li is lightest metal and has one of the highest
standard reduction potentials (-3.0 V)
 Theoretical specific capacity of 3860 Ah/kg in
comparison with 820 Ah/kg for Zn and 260 Ah/kg
for Pb

12. Lithium ion secondary
batteries
 The first commercial lithium-ion battery was
released by Sony in 1991
 Battery performance is related not only capacity
but also to how fast current can be drawn from it:
specific energy (Wh/Kg), energy density (Wh/cm3)
and power density (W/Kg)

13. Schematic representation of a Lithium-ion cell

14. Upon charging, lithium ions are released by the cathode and
intercalated at the anode.
When the cell is discharged, lithium ions are extracted by the
cathode and inserted into the anode.

15. Advantages of Lithium-ion batteries
POWER – High energy density means greater power
in a smaller package.
◦ 160% greater than NiMH
◦ 220% greater than NiCd
HIGHER VOLTAGE – a strong current
allows it to power complex mechanical
devices.
LONG SHELF-LIFE – only 5% discharge
loss per month.
10% for NiMH, 20% for NiCd

16. Disadvantages of Lithium-ion batteries
 EXPENSIVE -- 40% more than NiCd
 DELICATE -- battery temperature must be monitored
from within (which raises the price), and sealed
particularly well
 REGULATIONS -- when shipping Lithium-ion
batteries in bulk (which also raises the price)
◦ Class 9 miscellaneous hazardous material
◦ UN Manual of Tests and Criteria

17. Electrolytes
 Role
1) ion conductor between cathode and anode
2) generally, Lithium salt dissolved in organic solvent
3) solid electrolyte is also possible if the ion conductivity is high at
operating temperature.
 Requirement
1) Inert
2) High ionic conductivity, low viscosity
3) low melting point
4) Appropriate concentration of Lithium salt
5) Chemical/thermal stability
6) Low cost
7) Environmental -friendly, non-toxic
 Commercial electrolytes: LiPF6 in Carbonate solvent

18. Anode materials
 Requirements
1) Large capability of Lithium adsorption
2) High efficiency of charge/discharge
3) Excellent cyclability
4) Low reactivity against electrolyte
5) Fast reaction rate
6) Low cost
8) Environmental -friendly, non-toxic
 Commercial anode materials:
Hard Carbon, Graphite

19. cathodematerials
 One facet of battery research in which there have
been many interesting discoveries is the area of
cathodes
 A cathode is the electrode of an electrochemical
cell at which reduction occurs
 Common cathode materials of Lithium-ion
batteries are the transition metal oxide based
compounds such as
LiCoO2, LiMn2O4, LiNiO2, LiFePO4

20. Desired characteristics of cathode
materials
 A high discharge voltage
Li
 A high energy capacity Co
c
O
 A long cycle life
 A high power density
 Light weight
a
 Low self-discharge LiCoO2
 Absence of environmentally
hazardous elements

21. Parameters effecting Cathode behavior
 Method of preparation
 Particle size
 Morphology
 Oxygen Deficiency
 Temperature

22. CATHODE MATERIALS
 Layered oxide cathodes
 Spinel oxide cathodes
 Zigzag layered LiMnO2 compound
 Olivine structure of LiMPO4
 Other compounds

23. CATHODE MATERIALS

24. Structures of cathode materials
Structures of different cathode materials for lithium ion batteries:
a) LiCoO 2 layered structure
b) LiMn2O4 spinel structure and
c)LiFePO4 olivine structure.
The green circles are lithium ions, Li+

25. LiFePO4 Advantages
1.Good Structural Stability--Safety, long life
2 . Fe and Phosphates are abundant-Low
cost
3 . Environmentally friendly-non toxic
elements
Disadvantages
a. LiFePO4 Structure 1.Slow Lithium-ion diffusion
2.Low electronic conductivity
Symmetry : 3.Lower power capability
Orthorhombic

26. Capacity ranges with respect to
various cathode materials

27. Comparison of cathode materials

28. Ways to Improve Cathode Performance
• Increasing Energy Density
• Investigate high voltage cathodes that can deliver all the
Lithium in the structure will improve energy density
• Thin nano-plate materials seem to offer more energy at
higher rate
• 30 nm LiFePO4 nano-plates performed better than thick
material
• Meso porous LiMn2O4 is another material where there is
reduced manganese dissolution
• Surface Coating of cathodes with either ionically or
electronically conductive material
• AlF3 coating on oxide materials is shown to improve
performance

29. Recent advances in lithium ion
battery cathode materials
 Composite Cathode Material for Lithium-ion
Batteries Based on LiFePO4 System
 Some transition metal (oxy)phosphates and
vanadium oxides for lithium batteries
 Nanostructured cathode materials

30. Problems in the usage of Cathode materials
 Raw material cost and environmental impact of
large-scale cells and mass production
 Production cost of solid-state synthesis using high
and long heating process
 Oxygen release and heat generation from the
cathode in a fully charged state
 Sensitivity of safety for charge cutoff voltages
 Sensitivity of cathode performance for
stoichiometry
 Low practical capacity of the cathode being half
that of a carbonaceous anode

31. Next generation cathodes
 Most abundant is iron, with stable trivalent state
 Second most abundant is titanium, with stable
tetravalent state
 Vanadium, with wide valence change (V 2+ –V 5+ )
 Molybdenum, with wide valence change (Mo 4+ –
Mo 6+ )

32. Potential Cathode Materials
1. Olivine based phosphates systems (LiMPO4 where M = Mn, Ni) that
can deliver more Lithium as compared to the conventional material
LiCoO2
2. Only very few groups have synthesized LiMnPO4 successfully
and this system has a potential around 4.3 V
3. LiNiPO4 has a potential around 5.5V. It is believed that Li+ diffusion
coefficient is quite high in nickel phosphate in the range 10-5 m2/s at
around room temperature. It should have high thermal stability
because the oxygen is covalently bound in the structure
4. Novel approaches for synthesis of nanostructured olivine's are required
to enhance both ionic and electronic conductivity
5. LiMn2O4 may be another potential candidate material if the Mn
dissolution can be suppressed
◦ Mesoporous oxide with coating may stabilize Mn oxide

33. Structures of some promising materials
Structures of LiFePO4 and FePO4, quartz-like
FePO4, Li3Fe2(PO4)3, Lipscombite
Fe1.33FePO4(OH), LiFePO4(OH), H2VOPO4 and H2MnOPO4, e-VOPO4 and
Li2VOPO4. PO4 tetrahedra are golden, FeO6 and VO6 octahedra are
blue, FeO4 tetrahedra are green and lithium atoms are green

34. Conclusions and what does the future
hold
 In present day common Lithium transition compounds such as
LiCoO2, LiNiO2, LiMn2O4 and LiFePO4 are used as cathode
material in battery cell production, and they have shown a good
performance during charge and discharge cycling
 For the future there are still a number of actions of interest to
further develop the performance of derived LiFePO4/C cathode
material
 We expect upcoming researches on this new framework will lead to
better cathode materials for lithium-ion batteries