Presented by Sameh Hamzawy Alagaraj Paulraj

1. D. Arumugam, G. Paruthimal Kalaignan, P. Manisankar
Solid State Ionics 179 (2010) 580 – 586
Sameh Hamzawy
Alagr Raj Paulraj
MESC9

2. Outline
 Introduction
 Experiment
 Results and discussion
 Conclusion

3.  Introduction
Advantages Disadvantages
LiCoO2 High specific capacity High cost
Better cyclic performance Toxicity
LiMn2O4 Inexpensive, relatively. Poor cycle performance
at high temperature.
Environmentally Capacity fading
Lithium-ion batteries have gained increasing importance
as power sources due to their high working voltage, low
self discharge rate, and long life.

4.  Reducing the amount of Mn3+ in LiMn2O4  improve
the cyclability of the materials.
 Substitute Mn by some metal species such as :
LiNixMn2−xO4, LiCoxMn2 −xO, LiLaxMn2 −xO4 ????
Experiment:
Spinel LiLaxMn2 – xO4 ,where x=0.00, 0.01, 0.03, 0.05
and 0.10 were synthesized by sol-gel method.

5. Results and discussion
X-ray diffraction pattern of the spinel LiMn2 O4 and
lanthanum substituted LiLaxMn2− x O 4 powders
prepared by sol – gel technique at 900 °C.
 Single phase
diffraction patterns for
the 5 samples
 Cubic spinel structure
 The intensity of the
diffraction peaks are
enhanced after doping,
indicating large crystal
size.

6. Lattice parameters, unit cell volume, and intensity ratios of spinel
LiLaxMn2 – xO4 , (x=0.00 to 0.10) cathode materials.
Increasing lanthanum doping , increases the lattice parameters
More lattice space for Li intercalation and deintercalation
Prevent lattice shrinking during the deintercalation

7. SEM image of LiMn2O4 and lanthanum substituted LiLaxMn2 – xO4 powders synthesized
at 900 °C. a) LiMn2 O4, b) LiLa0.01Mn1.99O4 , c) LiLa0.03Mn1.97O4 , d) LiLa0.05Mn1.95O4 and
e) LiLa0.10Mn1.90O4.

8. Raj’s part

9. Raman Spectroscopy
 Local symmetrical
properties
 Sensitive to the
short range
environment of
cations and the
coordinated oxygen
ions.

10. Galvanostatic charge/discharge studies
Cycling was done
between 2.75V to 4.5
V @ .1c Current
density
Two plateaus one
at4.05 &another 4.15

11. Cyclic Voltammetery
LiMn2O4
LiLa0.01Mn1.99O4
LiLa0.05Mn1.95O4
LiLa0.10Mn1.90O4

12. Life Cycle Test
LiMn2O4
LiLa0.05Mn1.95O4

13. Rate capability of LiLa0.05Mn1.95O4
C Rate Intial
stage
capacity
(mAh/g)
Capacity
After 50
cycles
(mAh/g)
.1c 127 115
.5 129 112
1 119 106
2 112 103
5 102 87

14. Conclusion
 The LiLa x Mn 2 − x O 4 (x=0.00, 0.01, 0.03, 0.05 ,0.10)
cathode materials were synthesized by low T sol-gel
method.
 single phase structure was conformed by XRD and
Raman ,Higher dopant level impurity phases were
present
 LiLa0.05Mn1.95O4 has excellent capacity retention.

15. Thank you