2. CONTENTS
• Primary vs secondary batteries
• Standard modern batteries
• Battery types
• Advantages & Disadvantages of Li-ion
• Silicon nanowire
• Advantage
• Disadvantage
• Future scope
• References
3. Primary vs. Secondary
Batteries
Primary batteries are disposable because
their electrochemical reaction cannot be
reversed.
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.
4. Standard Modern Batteries
Zinc-Carbon: used in all inexpensive AA, C and
D dry-cell batteries. The electrodes are zinc and
carbon, with an acidic paste between them that
serves as the electrolyte. (disposable)
Alkaline: used in common Duracell and Energizer
batteries, the electrodes are zinc and manganese-
oxide, with an alkaline electrolyte. (disposable)
Lead-Acid: used in cars, the electrodes are lead
and lead-oxide, with an acidic electrolyte.
(rechargeable)
6. Lithium -Ion Battery
Development
In the 1970’s, Lithium metal was used but
its instability rendered it unsafe and
impractical. Lithium-cobalt oxide and
graphite are now used as the lithium-Ion-
moving electrodes.
The Lithium-Ion battery has a slightly
lower energy density than Lithium metal,
but is much safer. Introduced by Sony in
1991.
7. Advantages of Using
Li-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
8. Disadvantages of Li-Ion
EXPENSIVE -- 40% more than NiCd.
DELICATE -- battery temp must be monitored
from within (which raises the price), and sealed
particularly well.
REGULATIONS -- when shipping Li-Ion
batteries in bulk (which also raises the price).
• Class 9 miscellaneous hazardous material
• UN Manual of Tests and Criteria (III, 38.3)
9. “Nano” Science and
Technology
1 sheet of paper = 100,000 nanometers
The attempt to manufacture and control
objects at the atomic and molecular level (i.e.
100 nanometers or smaller).
1 nanometer = 1 billionth of a meter (10-9)
10. Silicon: an optimal anode
material
Graphite energy density: 372 mA h/g
C6 LiC6
Silicon energy density: 4200 mA h/g
Si Li4.4Si
11. Silicon NW Anode
Structurally stable after many
cycles
10 x energy density of current
anodes
Silicon film gets pulverized
from volume changes.
Si NW can accommodate
volume change.
12. Experimental Technique
NW growth on stainless steel by vapor-liquid-solid (VLS)
technique
Crystalline Si
Core-shell (core = crystalline Si, shell = amorphous Si)
Test current-voltage characteristics over many
charge/discharge cycles using cyclic voltammetry
C
Si NW on
Stainless steel
Li metal
Electrolyte
V
14. Experimental Results
Chan et. al., Nature Nanotech, 200
Charge and discharge capacity per cycle
Dramatic (~10x) improvement in
charging capacity over graphite!
14
15. Experimental Results
Chan et. al., Nature Nanotech, 200
Charge and discharge capacity per cycle
No decrease in capacity beyond
first charge cycle!
15
16. Experimental Results
Chan et. al., Nature Nanotech, 200
Study of reaction dynamics:
Near capacity charging at high reaction rates
16
17. Experimental Results
Chan et. al., Nature Nanotech, 200
Study of reaction dynamics:
Near capacity charging at high reaction rates
Even one hour cycle time
is much better than a fully
charged graphite anode!
Graphite
17
18. Technological Comparison
Technology Power density Energy
density
Lifetime Efficiency
Fuel cells Low/moderate High Low/moderate Moderate
Supercapacitors Very high Low High High
Nanogenerators Very low Unlimited Unknown Low
Li-ion w/ graphite Moderate Moderate Moderate High
Li-ion w/ Si NW Moderate High Under
investigation
High
Fuel Cells:
Smithsonian Institution, 2008
18
19. Technological Comparison
Supercapacitors:
Maxwell Technologies, 2009
19
Technology Power density Energy
density
Lifetime Efficiency
Fuel cells Low/moderate High Low/moderate Moderate
Supercapacitors Very high Low High High
Nanogenerators Very low Unlimited Unknown Low
Li-ion w/ graphite Moderate Moderate Moderate High
Li-ion w/ Si NW Moderate High Under
investigation
High
20. Technological Comparison
Piezoelectric
nanogenerators:
Wang, ZL, Adv. Funct. Mater., 2008
20
Technology Power density Energy
density
Lifetime Efficiency
Fuel cells Low/moderate High Low/moderate Moderate
Supercapacitors Very high Low High High
Nanogenerators Very low Unlimited Unknown Low
Li-ion w/ graphite Moderate Moderate Moderate High
Li-ion w/ Si NW Moderate High Under
investigation
High
21. Technological Comparison
Energy and power density
Only fuel cells and batteries can be primary power supply
Among those, Si NW batteries are optimal
Lifetime and efficiency
Batteries last about as long as typical electronic components
Energy efficiency of electrochemical devices is generally high
21
Technology Power density Energy
density
Lifetime Efficiency
Fuel cells Low/moderate High Low/moderate Moderate
Supercapacitors Very high Low High High
Nanogenerators Very low Unlimited Unknown Low
Li-ion w/ graphite Moderate Moderate Moderate High
Li-ion w/ Si NW Moderate High Under
investigation
High
22. Economics of Nanowire
Batteries
Silicon is abundant and cheap
Leverage extensive silicon production infrastructure
Don’t need high purity (expensive) Si
Nanowire growth substrate is also current collector
Leads to simpler/easier battery design/manufacture (one
step synthesis)
Nanowire growth is mature and
scalable technique
J.-G. Zhang et al., “Large-Scale Production of Si-
Nanowires for Lithium Ion Battery Applications” (Pacific
Northwest National Laboratory)
9 sq. mi. factory = batteries for 100,000 cars/day
22
23. Lifetime Issues
Initial capacity loss after first cycle (17%)
Cause still unknown?
Capacity stable at ~3500 Ah/kg for 20 cycles
Can’t yet maintain theoretical 4200 Ah/kg
Crystalline-Amorphous Core-Shell Nanowires (2009)
Energy Density: ~1000 Ah/kg (3x)
90% retention, 100 cycles
Power Density: ~6800 A/kg (20x)
23
24. Why Are Nanowires Batteries
Not Being Implemented?
Nanowire are not being heavily manufactured because
they are still in the development stage and are only
produced in the laboratory.
Until production has been streamlined, made easier
and faster, they will not be heavily manufactured for
commercial purposes.
25. Advantages
The small NW diameter allows for better
accommodation of the large volume changes without
the initiation of fracture that can occur in bulk or
micron-sized materials.
NWs have direct 1D electronic pathways allowing for
efficient charge transport.
In nanowire electrodes the carriers can move
efficiently down the length of each wire.
Nanowires can be grown directly on the metallic
current collector.
Protects from explosions.
High storage capacity(4200mAh).
26. Disadvantage
NWs must be assembled into a composite containing
conducting carbon and binders to maintain good
electronic conduction throughout.
It is expensive.
Only anodes are manufactured by nanowires.
27. Future scope
In future, ordinary batteries will be replaced by
Nanowire based batteries completely.
By the use of Nanowire batteries in future, we can
have devices having high battery life.
By invention of some new mechanism and technology
, we can get Nanowire batteries have more than
10times the ordinary battery.
28. References
Porous Doped Silicon Nanowires for Lithium Ion Battery Anode with
Long Cycle Life Mingyuan Ge, Jiepeng Rong, Xin Fang, and Chongwu
Zhou
C. K. Chan, R. Huggins, Y. Cui and co-workers Nature Nanotechnology
3, 31 (2008)
Nanowire Batteries for Next Generation Electronics Candace K. Chan,
Stephen T. Connor, Yuan Yang, Ching-Mei Hsu, Robert A. Huggins,
and Yi Cui
Electrochemical Nanowire Devices for Energy Storage Liqiang Mai,
Qiulong Wei, Xiaocong Tian, Yunlong Zhao, and Qinyou An IEEE
TRANSACTIONS ON NANOTECHNOLOGY, VOL. 13, NO. 1,
JANUARY 2014
Proceedings of the 14th IEEE International Conference on
Nanotechnology Toronto, Canada, August 18-21, 2014 High-Rate
Lithium-ion Battery Anodes Based on Silicon-Coated Vertically Aligned
Carbon Nanofibers Steven A. Klankowski, Gaind P. Pandey, Brett A.
Cruden, Jianwei Liu, Judy Wu, Ronald A. Rojeski and Jun Li, Member,
IEEE
