ABSTRACT

The Batteries form a significant part of many electronic devices.

Typical
electrochemical batteries or cells convert chemical energy into
electrical energy.
Batteries based on the charging ability are classified into primary
and secondary
cells. Secondary cells are widely used because of their rechargeable
nature.
Presently, battery takes up a huge amount of space and contributes
to a large
part of the device's weight. There is strong recent interest in
ultrathin, flexible, safe
energy storage devices to meet the various design and power needs
of modern
gadgets. New research suggests that carbon nanotubes may
eventually provide the
best hope of implementing the flexible batteries which can shrink
our gadgets even
more.
The paper batteries could meet the energy demands of the next
generation
gadgets. A paper battery is a flexible, ultra-thin energy storage and
production
device formed by combining carbon nanotubes with a conventional
sheet of
cellulose-based paper. A paper battery acts as both a high-energy
battery and super
capacitor, combining two components that are separate in
traditional electronics.
This combination allows the battery to provide both long-term,
steady power
production and bursts of energy. Non-toxic, flexible paper batteries
have the
potential to power the next generation of electronics, medical
devices and hybrid
vehicles, allowing for radical new designs and medical
technologies.
The various types of batteries followed by the operation principle,
manufacturing and working of paper batteries are discussed in
detail.
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Table of Contents
Chapter _______________ Page no
1. Introduction to batteries………………………………………..
…………1
1.1Terminologies…………………………………………………
…...2
1.2Principle of operation of cell …………………………….…….…..4
1.3Types of
battery…………………………………………………....5
1.4Recent
developments……………………………………………....6
1.5Life of battery…………………………………………….
……......7
1.6Hazards...…………………….………………………...
…………..8
2. Paper Battery………………………….……………………...
…………..9
3. Carbon nanotubes……………………….
………………………………..12
3.1Properties of carbon
nanotubes……………………………………14
4. Fabrication of paper battery…………….…………….
…………………..15
5. Working of paper battery………………….………..
………………….....18
6. Advantages of paper battery……………………...
…………………..…..21
7. Limitations of paper battery…………………..
…………………….........22
8. Applications of paper battery………………...…………………….
…….22
9. Conclusion……………………………………………………….
…..…..24
References………………………………………………………..…..
…..25
4
List of Figures
Figures Description
Figure 1a……………………………………Symbolic View of the
Battery
Figure 1b…………………………………...Conventional Battery
Figure 1.2…………………………………..Principle Operation of
Battery
Figure 1.3a………………………………....Primary cell
Figure 1.3b………………………………....Secondary cell
Figure 1.4………………………………..…USB cell
Figure 1.5………………………………..…Life of Battery
Figure 1.6………………………………..…Electronic Waste
Figure 2………………………………….....Paper Battery
Figure 2.1………………………………….Types of CNTs
Figure 3………………………………….....Carbon nanotubes
Figure 3.1…………………………………..Relation b/w resistence
vs. width
Figure 3.2…………………………………..Relation b/w resistivity
vs. temp.
Figure 4………………………………….....Fabrication Process
Figure 4.1………………………………......Paper Battery
Figure 4.2…………………………………..Sechemetic of
fabrication process
5
Figure 5………………………………….....working of paper
battery
Figure 5.1………………………………….Testing of paper battry
6
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1. INTRODUCTION TO BATTERIES
An electrical battery is one or more electrochemical cells that
convert stored
chemical energy into electrical energy. Since the invention of the
first battery in
1800 by Alessandro Volta, batteries have become a common
power source for
many household and industrial applications.
Batteries are represented symbolically as
Fig. 1a Symbolic view Fig. 1b conventional
battery
Electrons flow from the negative terminal towards the positive
terminal.
Based on the rechargeable nature batteries are classified as
a. Non rechargeable or primary cells
b. Rechargeable or secondary cells
Based on the size they are classified as
a. Miniature batteries
b. Industrial batteries
Based on nature of electrolyte
8
a. Dry cell
b. Wet cell
1.1 Terminologies
1.1.1 Accumulator - A rechargeable battery or cell
1.1.2 Ampere-Hour Capacity - The number of ampere-hours which
can be
delivered by a battery on a single discharge.
1.1.3 Anode - During discharge, the negative electrode of the cell
is the
anode. During charge, that reverses and the positive electrode of
the cell is
the anode. The anode gives up electrons to the load circuit and
dissolves into
the electrolyte.
1.1.4 Battery Capacity - The electric output of a cell or battery on a
service
test delivered before the cell reaches a specified final electrical
condition and
may be expressed in ampere-hours, watt- hours, or similar units.
The
capacity in watt-hours is equal to the capacity in ampere-hours
multiplied by
the battery voltage.
1.1.5 Cutoff Voltage final - The prescribed lower-limit voltage at
which
battery discharge is considered complete. The cutoff or final
voltage is
usually chosen so that the maximum useful capacity of the battery
is
realized.
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1.1.6 C - Used to signify a charge or discharge rate equal to the
capacity of
a battery divided by 1 hour. Thus C for a 1600 mAh battery would
be 1.6 A,
C/5 for the same battery would be 320 mA and C/10 would be 160
mA.
1.1.7 Capacity - The capacity of a battery is a measure of the
amount of
energy that it can deliver in a single discharge. Battery capacity is
normally
listed as amp-hours (or milli amp-hours) or as watt-hours.
1.1.8 Cathode - Is an electrode that, in effect, oxidizes the anode or
absorbs
the electrons. During discharge, the positive electrode of a voltaic
cell is the
cathode. When charging, that reverses and the negative electrode of
the cell
is the cathode.
1.1.9 Cycle - One sequence of charge and discharge.
1.1.10 Cycle Life - For rechargeable batteries, the total number of
charge/discharge cycles the cell can sustain before its capacity is
significantly reduced. End of life is usually considered to be
reached when
the cell or battery delivers only 80% of rated ampere- hour
capacity.
1.1.11 Electrochemical Couple - The system of active materials
within a cell
that provides electrical energy storage through an electrochemical
reaction.
1.1.12 Electrode - An electrical conductor through which an
electric current
enters or leaves a conducting medium
10
1.1.13 Electrolyte - A chemical compound which, when fused or
dissolved in
certain solvents, usually water, will conduct an electric current.
1.1.14 Internal Resistance - The resistance to the flow of an
electric current
within the cell or battery.
1.1.15 Open-Circuit Voltage - The difference in potential between
the
terminals of a cell when the circuit is open (i.e., a no-load
condition).
1.1.16 Voltage, cutoff - Voltage at the end of useful discharge.
(See Voltage,
end-point.)
1.1.17 Voltage, end-point - Cell voltage below which the
connected
equipment will not operate or below which operation is not
recommended.
1.2 Principal of Operation of cell
A battery is a device that converts chemical energy directly to
electrical
energy. It consists of a number of voltaic cells. Each voltaic cell
consists of two
half cells connected in series by a conductive electrolyte
containing anions and
cations. One half-cell includes electrolyte and the electrode to
which anions
(negatively charged ions) migrate, i.e., the anode or negative
electrode. The other
half-cell includes electrolyte and the electrode to which cations
(positively charged
ions) migrate, i.e., the cathode or positive electrode. In the redox
reaction that
powers the battery, cations are reduced (electrons are added) at the
cathode, while
anions are oxidized (electrons are removed) at the anode. The
electrodes do not
touch each other but are electrically connected by the electrolyte.
Some cells use
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commonly used in portable devices that have low current drain, are
only used
intermittently, or are used well away from an alternative power
source, such as in
alarm and communication circuits where other electric power is
only intermittently
available. Disposable primary cells cannot be reliably recharged,
since the
chemical reactions are not easily reversible and active materials
may not return to
their original forms. Battery manufacturers recommend against
attempting
recharging primary cells. Common types of disposable batteries
include zinc-
carbon batteries and alkaline batteries.
Secondary batteries: These batteries must be charged before use.
They are
usually assembled with active materials in the discharged state.
Rechargeable
batteries or secondary cells can be recharged by applying electric
current, which
reverses the chemical reactions that occur during its use. Devices
to supply the
appropriate current are called chargers or rechargers.
Fig. 1.3a Primary cell Fig. 1.3b Secondary cell
1.4 Recent developments
Recent developments include batteries with embedded
functionality such as
USBCELL, with a built-in charger and USB connector within the
AA format,
13
enabling the battery to be charged by plugging into a USB port
without a charger
USB Cell is the brand of NiMH rechargeable battery produced by
a company
called Moixa Energy. The batteries include a USB connector to
allow recharging
using a powered USB port. The product range currently available
is limited to a
1300 mAh.
Fig. 1.4 USB cell
1.5 Life of battery
Even if never taken out of the original package, disposable (or
"primary")
batteries can lose 8 to 20 percent of their original charge every
year at a
temperature of about 20°–30°C. [54] This is known as the "self-
discharge" rate and
is due to non-current-producing "side" chemical reactions, which
occur within the
cell even if no load is applied to it. The rate of the side reactions is
reduced if the
batteries are stored at low temperature, although some batteries can
be damaged by
freezing. High or low temperatures may reduce battery
performance. This will
14
affect the initial voltage of the battery. For an AA alkaline battery
this initial
voltage is approximately normally distributed around 1.6 volts.
Rechargeable batteries self-discharge more rapidly than disposable
alkaline
batteries, especially nickel-based batteries a freshly charged NiCd
loses 10% of its
charge in the first 24 hours, and thereafter discharges at a rate of
about 10% a
month. Most nickel-
based batteries are partially discharged when purchased, and must
be charged
before first use.
1.6 Hazards related to batteries
1.6.1 Explosion
A battery explosion is caused by the misuse or malfunction of a
battery, such as
attempting to recharge a primary (non-rechargeable) battery, or
short circuiting a
battery.
1.6.2 Corrosion
Many battery chemicals are corrosive, poisonous, or both. If
leakage occurs, either
spontaneously or through accident, the chemicals released may be
dangerous
Fig 1.5 Life cycle
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1.6.3 Environmental pollution
The widespread use of batteries has created many environmental
concerns, such as
toxic metal pollution. Battery manufacture consumes resources and
often involves
hazardous chemicals. Used batteries also contribute to electronic
waste.
Americans purchase nearly three billion batteries annually, and
about 179,000 tons
of those end up in landfills across the country.
1.6.4 Ingestion
Small button/disk batteries can be swallowed by young children.
While in the
digestive tract the battery's electrical discharge can burn the tissues
and can be
serious enough to lead to death.
Fig 1.6 Electronic waste
2. PAPER BATTERY
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Energy has always been spotlighted. In the past few years a lot of
inventions
have been made in this particular field. The tiny nuclear batteries
that can provide
energy for 10 years, but they use radioactive elements and are
quite expensive.
Few years back some researchers from Stanford University started
experiments
concerning the ways in which a copier paper could be used as a
battery source.
After a long way of struggle they, recently, concluded that the idea
was right. The
batteries made from a plain copier paper could make for the future
energy storage
that is truly thin.
The anatomy of paper battery is based on the use of Carbon
Nanotubes tiny
cylinders to collect electric charge. The paper is dipped in lithium
containing
solution. The nanotubes will act as electrodes allowing storage
device to conduct
electricity. It’s astounding to know that all the components of a
conventional
battery are integrated in a single paper structure; hence the
complete mechanism
for a battery is minimized to a size of paper.
One of the many reasons behind choosing the paper as a medium
for battery
is the well-designed structure of millions of interconnected fibers
in it. These fibers
can hold on carbon nanotubes easily. Also a paper has the
capability to bent or
curl.
You can fold it in different shapes and forms plus it as light as
feather. Output
voltage is modest but it could be increased if we use a stack of
papers. Hence the
voltage issues can be easily controlled without difficulty. Usage of
paper as a
battery will ultimately lead to weight diminution of batteries many
times as
compared to traditional batteries.
It is said that the paper battery also has the capability of releasing
the energy
quickly. That makes it best utilization for devices that needs burst
of energy,
17
mostly electric vehicles. Further, the medical uses are particularly
attractive
because they do not contain any toxic materials.
Fig.2 Papper Battry
A paper battery is a flexible, ultra-thin energy storage and
production device
formed by combining carbon nanotubes with a conventional sheet
ofcellulosebased
paper. A paper battery acts as both a highenergy battery and super
capacitor,
combining two discrete components that are separate in traditional
electronics.
Paper Battery= Paper (Cellulose) + Carbon Nanotubes
Cellulose is a complex organic substance found in paper and pulp;
not digestible
by humans. A Carbon NanoTubes (CNT) is a very tiny cylinder
formed from a
single sheet of carbon atoms rolled into a tiny cylinder. These are
stronger than
steel and more conducting than the best semiconductors. They can
be Single-
walled or Multi-walled.
Mayer-rod-coated on the paper substrate with an effective
thickness of 10 _m. The
wet PVDF functions as a glue to stick the double layer films on
paper. The
concentration of PVDF in N-methyl-2-pyrrolidone (NMP) was
10% by weight the
double layer films were laminated on the paper while the PVDF/
NMP was still
wet. During this process, a metal rod rolls over the films to remove
air bubbles
trapped between films and the paper separator. After laminating
LTO/CNT on one
18
side of the paper, the same process was used to put LCO/CNT on
the opposite side
of the paper to complete the Li-ion battery fabrication. Figure 1d,e
shows the
scheme and a final device of the Li-ion paper battery prior to
encapsulation and cell testing. Althougha paper-like membrane has
been used as
the separator for other energy storage systems including
supercapacitors, it is the
first demonstration of the use of commercial paper in Li-ion
batteries, 12 where
paper is used as both separator and mechanical support.
Fig2.1 Types of CNTs
3. CARBON NANOTUBES
Carbon nanotubes (CNTs) are allotropes of carbon with a
cylindrical
nanostructure. Nanotubes have been constructed with length-to-
diameter ratio of
up to 132,000,000:1, significantly larger than any other material.
These cylindrical
carbon molecules have novel properties, making them potentially
useful in many
applications in nanotechnology, electronics, optics, and other fields
of materials
science, as well as potential uses in architectural fields.
They may also have applications in the construction of body
armor. They
exhibit extraordinary strength and unique electrical properties, and
are efficient
thermal conductors.
19
Their name is derived from their size, since the diameter of a
nanotube is on
the order of a few nanometers (approximately 1/50,000th of the
width of a human
hair), while they can be up to 18 centimeters in length (as of 2010).
Nanotubes are
categorized as single-walled nanotubes (SWNTs) and multi-walled
nanotubes
(MWNTs).
In theory, metallic nanotubes can carry an electric current density
of 4 × 109
A/cm2 which is more than 1,000 times greater than metals such as
copper, where
for copper interconnects current densities are limited by electro
migration.
In paper batteries the nanotubes act as electrodes, allowing the
storage
devices to conduct electricity. The battery, which functions as both
a lithium-ion
battery and a super capacitor, can provide a long, steady power
output comparable
to a conventional battery, as well as a super capacitor’s quick burst
of high energy
and while a conventional battery contains a number of separate
components, the
paper battery integrates all of the battery components in a single
structure, making
it more energy efficient.
Carbon nanotubes have been implemented in Nano
electromechnical
systems, including mechanical memory elements(NRAM being
developed by
Nantero Inc.)
Fig 3. Carbon nanotubes
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3.1 Properties of Carbon Nanotubes:
• Ratio of Width: Length: 1:107
• High tensile Strength (Greater than Steel).
• Low Mass density & High Packing Density.
• Very Light and Very Flexible.
• Very Good Electrical Conductivity (better than Silicon).
• Low resistance (~33 ohm per sq. inch).
• Output Open Circuit Voltage(O.C.V): 1.5-2.5 V (For a postage
stamp sized)
• The O.C.V. of Paper Batteries is directly proportional to CNT
concentration.
• Stacking the Paper and CNT layers multiplies the Output
Voltage; Slicing the
Paper and CNT layers divides the Output Voltage.
• Thickness: typically about 0.5-0.7mm.
• Nominal continuous current density: 0.1 mA/cm2/ active area.
• Nominal capacity: 2.5 to 5 mAh/cm2/ active area.
• Shelf life (RT): 3 years.
• Temperature operating range: -75°C to +150°C.
• No heavy metals (does not contain Hg, Pb, Cd, etc.)
• No safety events or over-heating in case of battery abuse or
mechanical damage
• No safety limitations for shipment, packaging storage and
disposal.
Fig3.1 Variation of Resistance with Width of CNT
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Fig3.2. Variation of Resistivity with Temperature
4. FABRICATION OF PAPER BATTERY
The materials required for the preparation of paper battery are
a. Copier paper
b. Carbon nano ink
c. Oven
The steps involved in the preparation of the paper battery are as
follows
Step 1: The copier paper is taken.
Step 2: carbon Nano ink which is black in color is taken. Carbon
nano ink is a
solution of nano rods, surface adhesive agent and ionic salt
solutions. Carbon nano
ink is spread on one side of the paper.
Step 3: the paper is kept inside the oven at 150C temperature. This
evaporates the
water content on the paper. The paper and the nano rods get
attached to each other.
Step 4: place the multi meter on the sides of the paper and we can
see voltage drop
is generated.
vvv