Improving the efficiency of normal batteries by using graphene (wonder material)

1. GRAPHENE-CAGED SILICON-
LITHIUM-ION BATTERIES IN
SMARTPHONES
V.RESHMA SONA , CHEMICAL ‘C’

2. ABSTRACT :
 More efficient smartphone batteries can be made
by replacing the graphite anode of Li-on battery by
Silicon .
 Practical Si-Li-on batteries can be produced by
encasing Slicon with graphene.

3. LITHIUM-ION BATTERY
 Cathode - Lithium cobalt oxide
 Anode - Graphite
 Electrolyte – Organic solvent containing Li salts
CHARGING - Li+ from cathode to anode
DISCHARGING – Li+ from anode to cathode

4. SILICON ANODES
Because ,
 High gravimetric capacity ( 4200 mAh/g )
 High volumetric capacity
 Cheap
 Environmentally benign
1 Li ↔ 6 C
1 Si ↔ 4.4 Li

5. SILICON-LITHIUM-ION
BATTERIES
 DRAWBACKS :
 Expansion and contraction of Si anode by 300%
Leads to Fracture & Pulverization of Si
Loss in electrical contact
Capacity fading
 Unstable SEI layer
During delithiation,breaks down into pieces
Formation of very thick SEI layer
Increases the electrode impedance

6. VOLUME VARIATION OF
SILICON

7. GRAPHENE
 ‘WONDER MATERIAL’
 First 2D crystal
 1 atom thick
 Strongest
 Hardest
 Lightest
 Thinnest
 Most flexible
 Chemically inert
 Very large surface area

8. GRAPHENE CAGING
Three step process :
1) Coating Si microparticles with Nickel of 2-5 µ
2) Layers of graphene are grown over this
3) Nickel is etched away with HF acid
 Using Si microparticles which are wastes from
making of semi-conductor chips
 1-3 microns
 Very cheap when compared with Si nanoparticles

9. GRAPHENE CAGING OF
SILICON

10. 10 TIMES EFFICIENT BATTERIES WITH
INCREASE IN ENERGY DENSITY BY 40-60%
 SPECIFIC ENERGY
100-265 Wh/kg
o SPECIFIC CAPACITY
372 mAh/g
1550 Wh/kg
4000 mAh/g
ORDINARY
BATTERY
Si-Li-ion
BATTERY

11. CONCLUSION
Graphene caged Silicon-Lithium-ion batteries
are the future smart batteries which will get charged
from 1 to 100% within 15 minutes ( approx ) . Once
charged , You can have your phones for 7
continuous days . Super-thin and light weight
batteries are possible in a very low cost ( since
using Si waste ) .Let’s forget power banks with
these super-efficient batteries .

12. REFERENCES
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energy lithium batteries.Energy Technol.1,77-84 ( 2013 )
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3.Xiao , J.et al. Stabilization of silicon anode for Li-on batteries.
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4.Lu,Z.etal.Nonfilling carbon coating of porous silicon
micrometer-sized particles for high-performance lithium
battery anodes.ACS Nano 9, 2540-2547 (2015)
5.Yuzhang Li,Kai Yan, Yi Cui ,Growth of conformal graphene
cages on micrometer-sized silicon particles as stable battery
anodes , Nature Energy 1, A15029 ( 2016 )