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STUDY OF ALUMINIUM BATTERIES AS ENERGY SOURCE

LOW CHEE LEONG



ii

DECLARATION

I hereby declare that this project report is based on my original work except for

citations and quotations which have been duly acknowledged. I also declare that it

has not been previously and concurrently submitted for any other degree or award at

UTAR or other institutions.



iii

APPROVAL FOR SUBMISSION

I certify that this project report entitled “STUDY OF ALUMINIUM BATTERIES

AS ENERGY SOURCE” was prepared by LOW CHEE LEONG has met the

required standard for submission in partial fulfilment of the requirements for the

award of Bachelor of Degree (Hons.) Chemical Engineering at UniversitiTunku

Abdul Rahman.



iv

The copyright of this report belongs to the author under the terms of the

copyright Act 1987 as qualified by Intellectual Property Policy of UniversityTunku

Abdul Rahman. Due acknowledgement shall always be made of the use of any

material contained in, or derived from, this report.

© 2013, Low Chee Leong.All right reserved.



v

Specially dedicated to

my beloved parents, siblings, lecturer and friends.



vi

ACKNOWLEDGEMENTS

I would like to thank everyone who had contributed to the successful completion of

this project. I would like to express my gratitude to my research supervisor, Miss

TeohHuiChiehfor her invaluable advice, guidance and her enormous patience

throughout the development of the research.

In addition, I would also like to express my appreciation to the beloved

friends who had helped me out when my project encounter the obstacles especially

Carina Hoon Huey Qi and Thanentiran Naidu a/I Subramaniam for checking out my

thesis. Their help is really encouraging me and make my works goes smoothly.

Moreover, I would like to thank to Chew Xing, Chan Junda, Lee Wei Pin and Tai

Wei Xian to figure out the problems with me. Their advices and suggestions are



vii

STUDY OF ALUMINIUM BATTERIES AS COVER

ABSTRACT

Al batteries included Al-air battery, Al-carbon battery and Al-copper battery. In this

project, an Al-air battery was constructed by replacing the cellulose nitrate

membrane with PTFE in a free-catalyst condition. This study focused on the

performance of the Al-batteries which can be affected by the parameters such as

surface area of anode and cathode, and type of electrolyte in different concentration.

The each result of the experiment was conducted over 30 minutes. The depletion

percentage was used to determine the stability of the cell. The higher surface area of

anode and cathode would lead to a higher current produced and lower depletion

percentage. As the concentration of the electrolyte increases, the conductivity of the

electrolyte is also increases. This implied that there are more ions to conduct the



viii

TABLE OF CONTENTS

DECLARATION ii

APPROVAL FOR SUBMISSION iii

ACKNOWLEDGEMENTS vi

ABSTRACT vii

TABLE OF CONTENTS viii

LIST OF TABLES xi

LIST OF FIGURES xiii

LIST OF APPENDICES xvi

CHAPTER



ix

2.3.2 Consideration of Cathode 16

2.3.3 Advantages and Disadvantages of Al-Carbon Battery

18

2.4 Aluminium-Copper Battery (Al-Copper Battery) 18

2.4.1 Working principles of Al-Copper Battery 18

2.4.2 Advantages and Disadvantages of Al-Copper Battery

19

2.5 Depletion of Current 20

2.5.1 Overpotential 20

2.5.2 Polarisation 20

2.5.3 Concentration Polarisation 21

3 METHODOLOGY 22

3.1 Background 22

3.2 Experiment Setup 23

3.2.1 Al-Air Battery 23

3.2.2 Al-Carbon Battery & Al-Copper Battery 24



x

4.3.2 Current at Time = 1 min 42

4.3.3 Current Depletion Percentage 44

4.4 Types of Solution in Different Concentration 46

4.4.1 Current 46

4.4.2 Voltages 48

4.4.3 Current Depletion Percentages 49

4.5 Parameters of Best Performance 51

5 CONCLUSIONS AND RECOMMENDATIONS 55

5.1 Conclusions 55

5.2 Recommendations 56

REFERENCES 57

APPENDICES 60



xi

LIST OF TABLES

TABLE TITLE PAGE

Table 1.1: The Price List of the Metal (Verma, 1994) 2

Table 2.1: Technical Specification of Cellulose Nitrate 13

Table 2.2: The Technical Data of the Double Sided Carbon Tape 17

Table 3.1: Summary of Comparison between Al-Air and Al-Carbon battery 26

Table 3.2: Summary of Comparison between Al-Carbon and Al-Copper battery 27

Table 3.3: Summary of Comparison between Al-Air and Al-

C b b 28



xii

Table 4.6: The Specification Parameters of the Best Performancein Al-Batteries 54



xiii

LIST OF FIGURES

FIGURE TITLE PAGE

Figure 1.1: Comparison between Aluminium and Zinc Anodes(Cuproban, 2009) 3

Figure 2.1: The Size of Conventional Battery and Metal-Air Battery (Toyota-Global.Com, 2012) 6

Figure 2.2: The Energy Densities of Various Types of Batteries(Jang Et Al., 2011) 7

Figure 2.3: The Theoretical Specific Energy of the Various MetalAir Batteries (National Aeronautics and SpaceAdministration [NASA], 2011) 7



xiv

Figure 3.2: Final Set Up of the Al-Air Battery (a) Front View (b)Back View 24

Figure 3.3: Final Setup of the Al-Copper Battery 25

Figure 3.4: The Preparation of Aluminium Anode in DifferenceSurface Area 25

Figure 3.5: The Preparation of Copper Cathode in DifferenceArea 28

Figure 4.1: Current Comparison between the Al-Air Battery andAl-Carbon Battery with Different Surface Area of Aluminium Anode at time = 1 min 35

Figure 4.2: Current Comparison between the Al-Carbon Batteryand Al-Copper Battery with Different Surface Area

of Aluminium Anode at time = 1 min 36

Figure 4.3: The (a) Reactivity series of metal (b) Standard RedoxPotential of Electrochemical Series 38

Figure 4.4: Depletion Percentages versus Surface Area anode between the Al-Air Battery and Al-Carbon Battery 39



xv

Figure 4.12: Current versus Concentration in DifferentElectrolyte at time = 1 Min in Al-Carbon Battery 47

Figure 4.13: Current versus Concentration in DifferentElectrolyte at time = 1 Min in Al-Copper Battery 48

Figure 4.14: Depletion Percentages of Current versusConcentration in Different Electrolyte in Al-Air Battery 49

Figure 4.15: Depletion Percentages of Current versusConcentration in Different Electrolyte in Al-CarbonBattery 50

Figure 4.16: Depletion Percentages of Current versusConcentration in Different Electrolyte in Al-Copper Battery 50



xvi

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Experiment Data 60



1

CHAPTER 1

1 INTRODUCTION

1.1 Background

Nowadays, households and industrial systems rely on the non-renewable and

unsustainable energy such as fossil fuel to generate energy. Fossil fuels are carbon-



2

Another sustainable chemical energy sources to replace the fossil fuels is

aluminium-batteries (Al-batteries) which is affordable and is environmental friendly.

According to Verma research (1994), the aluminium and zinc are among the cheapest

metal material which cost only $1.66/kg and $1.32/kg respectively. The Figure 1.1

shows the price list of metal on world market.

Table 1.1: The Price List of the Metal (Verma, 1994)

MetalM x 10

- a

(kg/mol)

Qm

($/kg)

Li 6.94 44.150

Na 23.00 2.052

Mg 24.32 2.958

Al 26.97 1.660

Zn 65.38 1.324

(a)M- mol.wt.

(b)Qm-price of metal ($) on world market (1982-1984)



3

compared to zinc anodes. In this way it is economically concerned and enhance of

performance by using aluminium rather than zinc (Cuproban, 2009).

The Al-batteries includes the aluminium-air (Al-air) battery, aluminium-

carbon (Al-carbon) battery and aluminium-copper (Al-copper) battery. In this project,

three types of Al-batteries are set up to compare the performance of each battery.

Figure 1.1: Comparison between Aluminium and Zinc Anodes (Cuproban, 2009)



4

1.3 Objectives of Study

The main objective of this study is to build the most suitable Al-battery under

optimum conditions among the three types of batteries. Thus, in order to do so, the

sub-objectives are listed as below:

1. To determine and investigate the construction an Al-air battery

2. To determine the performance of the Al-batteries with different surface area

of anodes

3. To determine the performance of the Al-batteries with different surface area

of cathodes

4. To determine the performance of Al-batteries in different types of electrolytes

in different concentration.



5

CHAPTER 2

2 LITERATURE REVIEW

2.1 Introduction

As mention in Chapter 1, the Al-batteries are recommended because the aluminum as

the anode material has plenty of advantages. Nevertheless, the cathode material and

the built up method are another parameters that can influence the performance of the



6

Metal-air batteries are lighter compared to the conventional batteries because

of its unique design. The most important advantage of metal – air batteries is that the

active cathode material (oxygen) is not stored in the battery itself, but is absorbed

from the surrounding environment during the discharge process. This unique

property leads to a lighter and more compact battery (WilliFord and Zhang, 2009).

The Figure 2.1 showed that the size of the conventional battery is bigger than the

metal-air battery due to the significant smaller size of cathode. With this, the metal-

air battery is lighter.



7

Figure 2.2: The Energy Densities of Various Types of Batteries (Jang Et Al.,

2011)

There are several types of metal-air batteries based on different metal speciesat anode. Most metal species including zinc, aluminum, and lithium, are important

and generally utilised in industries due to their high power density. Figure 2.3

provided the comparison of the theoretical energy density among all the metal-air

batteries. It is no doubt that the Li-air battery, Al-air battery and Zn-air battery



8

sensitive to moisture. The other is a water-sensitive system using an electrolyte with

aprotic solvents. This system is degraded by moisture (Jang et al., 2011). Aprotic

solvents such as acetone (CH3COCH3), DMSO (dimethylsulfoxide, CH3SOCH3),

HMPA, can't do H-bonding with the NUC because they have no H covalently

bonded to an electronegative element of the solvent [Jim Hollister]. Based on the

research by Gil Cohn and YairEin-Eli (2010), they utilise aqueous alkaline solutions

due to the high conductivity of such electrolyte and the outstanding ability to regulate

the reduced oxygen ion into hydroxide anions.

The power output of the system is directly related to the concentration and

surface area of both the cathode and the anode. Thus, in order to increase the surface

area of the electrode, the length of the electrode is adjustable. The longer is the

length of the electrode, the higher the surface area of it. Moreover, the distance

between electrodes could be an issue to affect the performance of the cell. Not much

of the reviews is discussing with this topic and in this study is going to investigate

and analyse it (Terre and Haute, 2004).



9

Figure 2.4: The Schematic Diagram of Metal Air Batteries (Cheng and Chen,

2012)

Figure 2.5 showed a typically type of Al-air battery. Al-air battery is

potentially attractive due to integration with aluminium industry, but aluminium-air

batteries have potential for ten to fifteen times the range of lead – acid batteries with a

far smaller total weight, at the cost of substantially increased system complexity. The

electrode reactions for an aluminum-air battery are as follows:

− −



10

2.2.2 Consideration for the Air Cathode

A typical O2-cathode comprised of a carbon black mixed with a polymericbinder.

The porous carbon O2-cathode is required to ensure a large electrolyte/electrode

surface area and accommodate the insoluble discharge product, as well as to facilitate

oxygen diffusion to the reaction site through the cathode film. In addition, the porous

carbon network must provide enough conductivity to deliver electrons to the reaction

site efficiently with low overall impedance. A homogenous distribution of a nano-

sized catalyst may also be required to maximise the performance by increasing the

round trip efficiency by lowering the voltage gap between charge and discharge

processes; however this has been challenged recently as discussed below. An exterior

O2 permeable membrane is required to prevent the ingress of water and carbon

dioxide, whilst still allowing the free passage of oxygen (Laurence and Peter, 2012)

The air cathode is a reactive layer of carbon contained between a nickel grid

current collector and a porous, hydrophobic PTFE film that serves to prevent leakage

of electrolyte. This results in a three-phase contact electrode. Gas, liquid and solid



11

Figure 2.6: The Aluminium Air Battery (A) The Essential Components Of The

Cell And The Species Involved In The Electrode Reactions (B) The Structure Of



12

with PTFE by a special technology. The catalytic layer contains a porous catalyst.

(Anastassia, 2005)

Figure 2.7 of the layered carbon electrode used as an air cathode in lithium air

cells. The PTFE is a Teflon membrane to repel water from the atmosphere. The “C”

is the carbon layer that contains the metal catalysts. Nickel mesh is the current

collector. (Authur et.al,2005)

Figure 2.7: The Air Cathode (Authur et al., 2005)



13

but in a cheaper price and thus, cellulose nitrated is applied. The technical

specification of cellulose nitrate is shown in Table 2.1.

Table 2.1: Technical Specification of Cellulose Nitrate

Technical Specification Cellulose Nitrate

Pore size 0.2 m

Thermal resistance 130 max

Thickness acc. 115-145 m

The carbon cathode is being further discussed and explained in Section 2.3.2

which is porous and conductive double layer carbon tape.

2.2.3 Advantages and Disadvantages of Metal-Air Batteries

Metal-air batteries are the most compact and potentially, the least expensive batteries

available. They are environmentally benign (Electricity Storage Association [ESA],

2011).



14

Electric Vehicles (HEV) prefers a lighter, longer life time, higher energy density

batteries and in the future which is an environmentally benign battery. Metal-air

batteries have fulfilled all the basic requirement of HEV. Figure 2.6.1 shows that a

officially an old fashion of battery is pretty big and pack in HEV.

Figure 2.8: A Li-Ion Battery in HEV



15

2.3 Aluminium-Carbon Battery (Al-Carbon Battery)

The Al-Carbon battery is an electrochemical cell that the aluminium is oxidized in

the anode whereas hydrogen ion is reduced to become hydrogen gas in the cathode

site. The application of electrochemical cells in portable power sources has been the

subject of extensive investigation. Apart from the obvious advantages of serving as

localized power sources, electrochemical cells provide pollution-free conversion of

chemical to electrical energy that is direct and, therefore, does not involve an

intervening heat cycle. This considerably increases the efficiency of the power

sources (Verma, 1994).

This redox reaction produced the current flow from cathode to anode. The

difference between the Al-carbon battery and Al-air battery is the set up method. The

cathode of the Al-air battery is exposed to the air on one side and another side is

being contact with the electrolyte. However, the cathode of Al-carbon battery is fully

dipped into the electrolyte to undergo the redox reaction.



16

Figure 2.9: The Setup Of Al-Carbon Battery (1) Solution (2) Graphite Cathode

(3) Aluminium Anode (4) Pyrex Glass Beaker (5) Milliameter (6) Resistance Box,

Millivoltmeter (Verma, 1994)

The electrode reactions for an Al-carbon battery are as follows:



17

electrode is to be used, the recess is packed with a paste that contains carbon

particles, and then the paste is carefully polished to a smooth disk-shaped surface.

Working with a carbon paste electrode is technically more demanding because the

paste can be gouged inadvertently after being polished [Pine Instrument Company,

2000]

The carbon cathode that been used in this project is the conductive porous

carbon tapes. This carbon tape is double-sided sticky and used for adhesion of SEM

specimen and applications in SEM where conductivity is required or for X-ray uses.

Table 2.2 showed the technical data of the double sided carbon tape and Figure 2.10

showed a carbon tape.

Table 2.2: The Technical Data of the Double Sided Carbon Tape

Technical Data Double sided Carbon Tape

Overall Thickness 12 mm

Adhesive 0.045 mm x 2

Conductive resistivity 50ohm/sq.Inch



18

2.3.3 Advantages and Disadvantages of Al-Carbon Battery

The advantages of the Al-carbon battery are mentioned in the Chapter 2.3. There are

pollution-free to environment and efficiency of the power sources. However, it is

found that activation polarization is the main factor that limits the current output

when using an untreated carbon electrode (Verma, 1994).

2.4 Aluminium-Copper Battery (Al-Copper Battery)

Al-Copper Battery is an electrochemical cell. Oxidation-reduction or redox reactions

take place in electrochemical cells. There are two types of electrochemical cells. The

redox reaction in a galvanic cell is a spontaneous reaction. For this reason, galvanic

cells are commonly used as batteries. Galvanic cell reactions supply energy which is

used to perform work. The energy is harnessed by situating the oxidation and

reduction reactions in separate containers, joined by an apparatus that allows

electrons to flow (About.com 2003).



19

Figure 2.11: The Activity Series of the Elements (Averill and Eldredge, 2007)

The electrode reactions for an Al-carbon battery are as follows:

− −



20

2.5 Depletion of Current

2.5.1 Overpotential

The deviation from equilibrium causes an electrical potential difference between the

polarized and the equilibrium (unpolarised) electrode potential known as

overpotential. There are two types of overpotetial, cathodic overpotential and anodic

overpotential which shown in Equation 2.1 and Equation 2.2.

Cathodic Overpotential, ηc = E – Eoc< 0 (2.1)

Anodic Overpotentialm, ηa = E – Eoa> 0 (2.2)

Where

Eoc = Equilibrium potential for cathodic reaction, V

Eoa = Equilibrium potential for anodic reaction, V

E = Real potential, V



21

First step: reduction of the hydrogen ions resulted in formation of atomichydrogen on the cathode surface.

H+ + e- = H

Second step: formation of molecules of gaseous hydrogen.

2H = H2

Third step: formation of hydrogen bubbles.

H2 + H2 + H2 +H2 + ... = nH2

The cathode is polarized by the hydrogen atoms producing a film covering

the cathode surface. The film affects the process kinetic: it slows down the reaction

between the electrons and hydrogen ions dissolved in the electrolyte (Substances &

Technologies [SubsTech], 2012).

2.5.3 Concentration Polarisation

Concentration polarization of an electrode is a result of formation of a diffusion layer

adjacent to the electrode surface where there is a gradient of the ion concentration.



22

CHAPTER 3

3 METHODOLOGY

3.1 Background

The main objective of this project is to compare the performances of Al-air battery,

Al-carbon battery and Al-copper battery. The performance of the Al-batteries fully

depends on the parameters of the experiment setup condition. The experiment



23

3.2 Experiment Setup

Different Al-battery has different setup method. In this Section, the fabrication

method of each battery is explained.

3.2.1 Al-Air Battery

In order to allow one side of the air cathode to be exposed toair and the other in

contact with an electrolyte, a container with a hole (5cm x 8cm) on one side for

fabrication of an air cathode is used. 40 cm2 of carbon tape was prepared, which is

shown in Figure 3.1 to cover the hole of the container. The cellulose nitrate which

replaces the PTFE is applied on it to prevent leakage of the solution. The round-

shaped cellulose nitrate is cut into squares to ensure that every surface of the carbon

cathode is covered to prevent leakage. Figure 3.2 shows the final setup of the Al-air

battery. This air cathode of Al-air battery is built without catalyst.



24

(a)

Porous non-wettable layer

Porous Catalytic partially

wettable conductive layer



25

Figure 3.3: Final Setup of the Al-Copper Battery

In Figure 3.3, the solution is placed in the beaker and the distance between the

electrodes is fixed at 12 cm.

3.3 Experiments Parameters

3.3.1 Surface Area of Anode



26

3.3.1.1 Comparison Between Al-Air Battery and Al-Carbon Battery

Comparisons between Al-air battery and Al-carbon battery were conducted to

compare the difference in different surface area of anode.

Fixed Variables:

1. 250 ml of 1M Sodium chloride (NaCl)

2. 12 cm distance between the electrodes

3. Cathode : 5 cm2 (250 ml) carbon (Al-air) and 5 cm2 carbon (Al-carbon)

Table 3.1: Summary of Comparison between Al-Air and Al-Carbon battery

Comparison

Between

Anode

(aluminium)

Surface Area

Fixed Cathode Surface Area

Al-air battery

&

16 cm2

24 cm2 5 cm2 (250 ml) carbon (Al-air)

2



27

Table 3.2: Summary of Comparison between Al-Carbon and Al-Copper battery

ComparisonBetween

Anode

(aluminium)

Surface Area

Fixed Cathode Surface Area

Al-carbon battery

&

Al-copper battery

16 cm2

24 cm2

35.2 cm2

40 cm2

80 cm2

29.7 cm2 carbon (Al-carbon)

29.7 cm2 copper (Al-copper)

Data Analysis: The voltages and amperes were recorded every 5 minutes. The graph

between the current density and the voltages against time is plotted.

3.3.2 Surface Area of Cathode

The surface area of the cathodes will affect the amperage of the battery and different



28

Table 3.3: Summary of Comparison between Al-Air and Al-Carbon battery

ComparisonBetween

Fixed Anode

(aluminium)

Surface Area

Carbon Cathode Surface Area

Al-air battery

&

Al-carbon battery

80 cm2

5 cm2

10 cm2

15 cm2

20 cm2

25 cm2


between the current density and the voltages against time is plotted.

3.3.2.2 Comparison between Al-Carbon Battery and Al-Copper Battery

The surface areas of the carbon tape cathode prepared are 14.85 cm 2, 29.7 cm2, 44.55

cm2, 59.4 cm2 and 74.25 cm2 as well. The surface area of a copper cathode is 14.85

2

29



29

Fixed Variables:

1. 1 M Sodium chloride (NaCl)

2. 12 cm between the electrode

3. 80 cm2Aluminium anode

Table 3.4: Summary of Comparison between Al-Carbon and Al-Copper battery

Comparison

Between

Fixed Anode

(aluminium)

Surface Area

Cathode Surface Area

Al-carbon battery

&

Al-copper battery 80 cm2

14.85 cm2

29.7 cm2

44.55 cm2

59.4 cm2

74.25 cm2


30



30

and KOH is highly exothermic, and the resulting heat may cause heat burns or ignite

flammables. Thus, all direct contact with organic tissue including human skin, eyes

and mouth must be avoided. Secondly, there are several materials that must be kept

away from this substance. One of the substances is aluminum. Any contact with

aluminum must be avoided because the combination of aluminum and NaOH results

in a large production of hydrogen gas as shown in the equation below:

2Al(s) + 6NaOH (aq) → 3H2 (g) + 2Na3AlO3 (aq).

Hydrogen gas is explosive and combustible, any ignition or fire might lead to

an explosion in the experiment lab. Therefore, the aluminum must be kept away from

NaOH and KOH at all times. The others substance is the strong acids which must not

be placed with strong base. Furthermore, NaOH should not come in contact with

nitroaromatic, nitroparaffinic or organohalogen compounds.

Thirdly, as mentioned earlier the alkaline reacts with metals like aluminum,

tin and zinc. Thus, it must not be transported in aluminum containers plus it also

reacts with glass. Hence, glass containers are not suitable for prolonged storage of

31



31

3.3.4 Different Concentration of Solution

Different types of aqueous solution were used to carry out the experiment to find out

the best performance of the system among the electrolytes in different concentrations.

Five concentrations of KOH, NaOH and HCl were prepared where the

concentrations were 0.1 M, 0.5 M, 1 M, 2 M and 3 M respectively.

Fixed Variables:

1. 250 ml of solution

2. 12 cm between the electrode

3. 80 cm2 of aluminium anode

4. 20 cm2(250ml) of carbon cathode ( Al-air battery)

29.7 cm2 of carbon cathode (Al-carbon battery)

29.7 cm2 of copper cathode (Al-copper battery)

32



32

Table 3.5: Summary of Different concentration in different solution

Al-batteries

Fixed Anode

(aluminium)

Surface Area

Fixed Cathode

Surface Area

Types of

Electrolyte

Concentration of

Electrolyte

Al-air

battery 80 cm2 20 cm2

(250 ml)

carbon

HCl

NaCl

KOH

0.1 M

0.5 M

1 M

2 M

3 M

Al-carbon

battery80 cm2

29.7 cm2 carbon HCl

NaCl

KOH

0.1 M0.5 M

1 M

2 M

3 M

33



33

3.4 Calculation of the Analysis

3.4.1 Depletion Percentage

The Depletion Percentage (D %) is used to determine the stability of the cell. The

experimental value (voltages and current) is calculated to determine if it has any

depletion. The Depletion Percentage is defined as:

Where

V s = value start ( t = 1 min)V f = value end ( t = 30 min)

If the depletion percentage is a negative value, it means that there is not

depletion but increasing of the current.

34



34

CHAPTER 4

4 RESULTS AND DISCUSSION

4.1 Background

The experiments were conducted and the results were recorded and discussed in this

chapter. The parameters that affected the performance of the battery as mentioned in

Chapter 3 were discussed in this chapter. The parameters which will be discussed for

35



4.2.1 Current at Time = 1 min

4.2.1.1 Comparison between Al-Air Battery and Al-Carbon Battery

Figure 4.1 showed the current comparison between the Al-Air battery and Al-carbon

battery using different surface area of aluminium anode. Both of the batteries were

conducted with fixed cathode surface area (5 cm2) of carbon cathode. The results

show that the current increased as the surface area of anode increased.

430

520

750780

3 4

4

5.1

5.9

7.1

3.5

4

4.5

5

5.5

6

6.5

7

7.5

250

350

450

550

650

750

850

C u r r

e n t o f A l - a i r b a t t e r y

( µ A )

C u r r e n t o f A l - C a r b o n

b a t t e r y

( µ A )

Al-Carbon Battery

36




The Figure 4.2 showed the current comparison between the Al-carbon battery and

Al- copper battery. Both of the batteries were conducted with the 29.7 cm2 of carbon

cathode. The Al-copper battery had a higher current as opposed to Al-carbon battery.

1.892.54

3.42

3.49

3.552.76

3.5

4.9

6.1

10.5

0

2

4

6

8

10

12

0 20 40 60 80 100

C u r r e n t ( m A )

Anode Area (cm2)

Al-Carbon Battery

Al Copper Battery

37



4.2.1.3 Discussion on Current and Voltage at Time = 1min Findings

The surface area of the electrodes will affect the number of ions that can be lost or

gained at the same time. If the surface area of the anode is greater, there will be more

aluminum ion and electron being produced in anode. Therefore, with greater surface

area more reactions may occur at the same time and thus increase the current show.

Theoretically the voltage of the batteries is not affected by the surface area of

electrode. The voltage of the Al-batteries is only determined by the potential between

two electrodes. According to the standard redox potential in Figure 4.3, the

equilibrium of Al-air battery theoretically occur at 2.06V and the Al-carbon battery

and Al-copper battery have the potential of 1.66 V. However, the measurement in

practice revealed a lesser potential difference which shown in Table 4.1. This

overpotential was occurred due to loss of voltage through polarisation. The

overpotential and the resistive potential drop across the cell must be established to

allow the reaction proceeds. They represented wasted energy.

38



Figure 4.3: The Standard Redox Potential of Electrochemical Series

39



In the Figure 4.4, Al-air batteries had the better setup of battery compared to

Al-carbon battery and Al-copper battery since the current depletion is negative. This

may be due to the oxygen was supplied into the cell unlimitedly.

Figure 4.4: Depletion Percentages versus Surface Area anode between the Al-

Air Battery and Al-Carbon Battery

65.88

65.81

63.46

60.0050.00

-26.47

-30.00-31.37

-37.29

-47.89

-60

-50

-40

-30

-20

-10

0

0

10

20

30

40

50

60

70

0 20 40 60 80 100

D % o f C u r r e n t o f A l - a i r b a t t e r y

D %

o f C u r r e n t o f A l - C a r b

o n b a t t e r y

Anode Surface Area (cm2)

Al-Carbon Battery

Al-Air Battery

40



Figure 4.5: Depletion Percentages versus Surface Area of anode between the Al-

Carbon Battery and Al-Copper Battery

4.2.2.3 Discussion on Current Depletion Percentage Findings

For all the three Al-batteries current depletion percentage decrease when the surface

60.14492754

54.28571429

51.02040816

44.26229508

40.95238095

42.32804233

36.22047244

35.96491228

34.67048711 30.70422535

25

30

35

40

45

50

55

60

65

70

0 20 40 60 80 100

D % o f C u r r e n t

Anode Surface Area (cm2)

Al-Copper Battery

Al-Carbon Battery

41



4.3 Surface Area of Cathode

The different surface area of carbon cathode was prepared in the experiments; they

were 5 cm2, 10 cm2, 14.85 cm2, 15cm2, 20 cm2and 25 cm2, 29.7 cm2, 44.55 cm2, 59.4

cm2and 74.25 cm2.

4.3.1 Investigation on New and Recycle Copper Cathode

An extra experiment has been conducted to test if a recycled copper will give a

different result from a new copper. This is because the copper has a higher cost if

conduct the experiments with a new copper. The result was shown in the Figure 4.6

that the recycled copper gave a lower current depletion percentage (D %) than the

new copper. The higher current D % of the new copper might be caused by theactivation of the copper surface. For recycled copper, the current would be likely

constant afterwards which shown in Table 4.2. The current is almost the same for the

new and recycled copper which around 1.28 mA at time = 5min. However, the new

copper will deplete to almost 0.325 mA at time = 30 min whereas the recycled

42



Table 4.2: The Average Current of the New and Recycled Copper at Time = 5

Min to Time = 30 Min in Al-Copper Battery

TimeCurrent (mA)

New copper Recycled Copper

5 1.29 1.28

10 0.82 0.79

15 0.47 0.715

20 0.42 0.71

25 0.345 0.71

30 0.325 0.71

Thus, the following experiment would be conducted by using the recycled

copper. It would get a higher value of data.

4.3.2 Current at Time = 1 min

43



Figure 4.7: Current Comparison between the Al-Air Battery and Al-Carbon

Battery in Different Surface Area of Cathode


In Figure 4.8, the current increased as the area of cathode was increased. It revealed

that the Al-copper battery had a higher current as opposed to Al-carbon battery This

8801500

3500

5900

8500

7

10.6

15.2

20.9

31.7

0

5

10

15

20

25

30

35

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

0 5 10 15 20 25 30

C u r r e n t o f A l - a i r b a t t e r y

( µ A )

C u r r e n t o f A l - C a r b o n b a t t

e r y

( µ A )

Cathode Area (cm2)

Al-Carbon Battery

Al-Air Battery

44



4.3.2.3 Discussion on Current at Time = 1 min

As same mentioned above (section 4.2), the higher the surface area of electrode

would give a higher value of current as with greater surface area more reactions may

occur at the same time and thus increase the current show. In this case, the surface

area of cathode increases and allows more electron being react with the cathode

material, and thus the current increases.

4.3.3 Current Depletion Percentage

The current depletion percentage against surface area of cathode between the Al-

carbon battery and Al-air battery were plotted in Figure 4.9 whereas between the Al-

carbon battery and Al-copper battery were plotted in Figure 4.10.

4.3.3.1 Comparison between Al-Air Battery and Al-Carbon Battery

Referring to Figure 4.9, in the cases of Al-air battery, the depletion percentage of the

45



Figure 4.9: Depletion Percentages versus Surface Area of Cathode between the

Al-Air Battery and Al-Carbon Battery


The Figure 4.10 shows that the high anode surface area will lead to a lower depletion

percentage The Al-copper battery has slightly higher depletion percentage than Al-

67.05

52.67

45.7142.37

38.82

-50.00

-58.96 -64.14-67.94

-71.92

-80

-70

-60

-50

-40

-30

-20

-10

0

0

10

20

30

40

50

60

70

80

0 5 10 15 20 25 30

D

% o f C u r r e n t o f A l - a i r b a t t e r y

D % o f

C u r r e n t o f A l - C a r b o n b a t t e r y

Cathode Area (cm2)

Al-Carbon Battery

Al-Air Battery

46



4.3.3.3 Discussion on Current Depletion Percentage Findings

By comparing the Figure 4.9 and Figure 4.10, the Al-batteries were concluded that

the depletion was decreased as the increase of the surface area of cathode which had

mentioned in section 4.2. This phenomenon might happen because the higher surface

area of cathode allowed more aluminum ion and electron being produced in anode

and react with the cathode material at the same time. The current was produced

almost at the same rate as the time over 30 minutes, and thus, the depletion of the battery was inhibited. Thus, the 25 cm2 of carbon cathode was preferred.

4.4 Types of Solution in Different Concentration

Three types of solutions were being chosen to be the electrolyte: strong acid, neutraland strong base. They are hydroxide chloride (HCl), sodium chloride (NaCl), and

potassium peroxide (KOH). These solutions were prepared in 0.1 M, 0.5 M, 1 M, 2

M and 3 M.

47



current around 45 mA in Al-copper battery. However, it has the disadvantages that

releasing of the H2 gas as well as it reacted with the aluminium.

Figure 4.11: Current versus Concentration in Different Electrolyte at time = 1

Min in Al-air Battery

10.7 14 15.2

20.7 39.1

40

87

151

214.4

265.2

16.4 18.3 19.5

20.520.9

0

50

100

150

200

250

300

0 0.5 1 1.5 2 2.5 3 3.5

C u r r e n t

( µ A )

Concentration

NaCl

KOH

HCl

48



Figure 4.13: Current versus Concentration in Different Electrolyte at time = 1

Min in Al-Copper Battery

4.4.2 Voltages

The voltages of the cell were not affected as the concentration increased.

Eff f i l f ll i ll Id ll f ld i i

9.75

14.07

19.09

20.11

23.51

4.3 6.1

10.9 12.5

17

15.1

20.89

24.89

40.12

43.56

0

5

10

15

20

25

30

35

40

45

50

0 0.5 1 1.5 2 2.5 3 3.5

C u r r e n t ( m A )

Concentration

HCl

NaCl

KOH

49



4.4.3 Current Depletion Percentages

Figure 4.14, Figure 4.15, and Figure 4.16 presented the current depletion percentagesversus concentration in different concentration in Al-Batteries. It concluded that the

depletion percentages of current were decreased with the concentration of the

electrolyte. The more concentrate of the electrolyte, the lesser is the depletion of the

current in the cell. However, the experiment of 2 M and 3 M of HCl could not be

carried out for 30 minutes due to the corrosion of the aluminium anode in the HClelectrolyte. The aluminium would break and detach from the crocodile clips, and at

the same time a large amount of H2 gas was produced.

However, in Figure 4.15, the depletion percentage was increased in 3 M of

electrolytes (NaCl and KOH) because concentrated solutions are less well ionisedand this factor may reduce the conductivity.

-10

0 0.5 1 1.5 2 2.5 3 3.5

Concentration

50



Figure 4.15: Depletion Percentages of Current versus Concentration in

Different Electrolyte in Al-Carbon Battery

75.25

64.06

79.52

70.62

78.18

42.23

39.3634.91 32.59

59.33

63.71 62.07 61.57

20

30

40

50

60

70

80

90

0 0.5 1 1.5 2 2.5 3 3.5

D %

o f C u r r e n t

Concentration

NaCl

KOH

HCl

51 16

60

51



4.5 Parameters of Best Performance

The experiments were repeated again in the best condition to get the voltage andcurrent value. The sample calculation was shown as below. The Table 4.3, Table 4.4

and Table 4.5 were the result of the battery in the best condition.

Table 4.3: Current and Voltages of Al-Air Battery with 80 cm2

of AluminiumAnode and 25 cm

2of Carbon Cathode in 3 M KOH.

Time

Current

(µA) Voltages (V)

1369.2 0.595

5417.5 0.604

10445.6 0.626

15492.8 0.641

20517.5 0.652

52



Table 4.4: Current and Voltages of Al-Carbon Battery with 80 cm2

of

Aluminium Anode and 74.25 cm2

of Carbon Cathode in 3 M KOH.

TimeCurrent

(mA) Voltages (V)

1 70.9 1.355

5 65.5 1.302

10 59.8 1.289

15 55.1 1.274

20 53.6 1.256

25 51.7 1.21

30 49.5 1.199

Average 58.01

The average current in the Al-carbon battery for the best parameters is 58.01 mA.

From Equation, 3.2, the current density of Al-carbon battery in 74.25 cm2 of carbon

cathode is

53

2



Table 4.5: Current and Voltages of Al-Copper Battery with 80 cm2

of

Aluminium Anode and 74.25 cm2

of Copper Cathode in 3 M KOH.

TimeCurrent

(mA) Voltages (V)

1 79.86 0.985

5 75.75 0.975

10 73.58 0.965

15 70.25 0.94220 68.12 0.918

25 62.53 0.857

30 59 0.817

Average 69.87

The average current in the Al-copper battery for the best parameters is 69.87 mA.

From Equation 3.2, the current density of Al-copper battery in 74.25 cm2 of carbon

cathode is

54



Table 4.6: The Specification Parameters of the Best Performance in Al-Batteries

Specification Technical Value

Anode Surface Area 80cm2

Cathode Surface Area

Al-air battery

25 cm2

Al-carbon battery 74.25 cm2

Al-copper battery 74.25 cm2

Electrolyte KOH

Concentration 3 M

Voltages induced

Al-air battery

0.595 V to 0.675 V

Al-carbon battery 1.199 V to 1.355 V

Al-copper battery 0.817 V to 0.985 V

Current Density

Al-air battery

⁄

Al-carbon battery 0.783 ⁄

Al-copper battery 0.941 ⁄

55



CHAPTER 5

5 CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusions

Among the three types of batteries, Al-copper battery has the best performance

because it has the highest current density, 0.941 mA/cm2. The Al-air battery

theoretically should have the highest current density but due to the difference

hydrophobic membrane used in the experiment and the absence of catalyst might

56

5 2 R d ti



5.2 Recommendations

The Al- batteries’ voltage could be increased in the following method. The magnitude

of electrode potential depends on the following factors as well. There is (i) Nature of

the electrode (ii) Concentration of the ions in solution, (iii) Temperature.

[Transtutors.com, 2013] It is fulfilling the Nernst equation. The Nernst equation will

have to be applied under nonstandard conditions:

where

Ecell = nonstandard cell potential, V

E˚cell = standard cell potential, V

R = 8.314 J/mol·K

T = temperature, K

n = moles of electrons transferred

57



REFERENCES

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History of Non-aqueous Metal-Air Batteries [Online]. Available at:

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th

December 2012]

Anastassia, K., 2005. Metal-Air Batteries: Research, Development, Application

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Angel, C., 2007. Introduction to Electrochemistry [Online]. Available at:

http://bouman.chem.georgetown.edu/S02/lect25/lect25.htm [Accessed 3September 2012]

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air battery [Online] Available at: http://ac els cdn com/S001346860600199X/1

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air battery [Online].Available at: http://ac.els-cdn.com/S001346860600199X/1-s2.0-S001346860600199X-main.pdf?_tid=aa6bbe82-99a3-11e2-bc0d-00000aacb35e&acdnat=1364694079_62c41d149e6857e732a726ea9238aadd[Acc

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Metal – Air Batteries with High Energy Density: Li – Air versus Zn – Air [Online].Available at:http://www.google.com.my/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CC8QFjAA&url=http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F227985366_MetalAir_Batteries_with_High_Energy_Density_LiAir_ver sus_ZnAir%2Ffile%2F79e4150bc00683d6b1.pdf&ei=el2IUdiNOs_NrQeIyICwB

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Keith, F. and Anthony, F., 1979 October. Metal/Air Batteries: Their Status And

Potential - A Review [Online]. Available at:

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Konstantin, I., Miomir, G. and Predrag, M., 2011. Current Density Distribution In

Electrochemical Cells [Online]. Available at:http://electrochem.cwru.edu/encycl/art-d03-curr-distr.htm[Accessed 12 November 2012]

Lan, C., Chin, T., Lin, P. and Perng, T., 2005. Zn-Al alloy as a new anode-metal of

i i b tt [O li ] A il bl t

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00000aacb361&acdnat=1364695025 0674e6545c30f0854f793aadf7892c2e

http://193.146.160.29/gtb/sod/usu/$UBUG/repositorio/10301212_Blurton.pdf

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60

APPENDICES


http://www.sciencedirect.com.libezp.utar.edu.my/science/article/pii/B978044452745500099X







APPENDIX A: EXPERIMENTS DATA

Figure A.1 Variation in Surface Area of Anode in Al-air battery

61

Figure A.2 Variation in Surface Area of Cathode in Al-air battery



62

Figure A.3 Variation in concentration of HCl in Al-air battery



63

Figure A.4 Variation in concentration of NaCl in Al-air battery



64

Figure A.5 Variation in concentration of KOH in Al-air battery



65

Figure A.6 (a) Variation in Surface Area of Anode in Al-carbon battery(Fixed Cathode: 5 cm2)



66

Figure A.6 (b) Variation in Surface Area of Anode in Al-carbon battery

(Fixed Cathode: 29 7cm2)



(Fixed Cathode: 29.7cm )

67

Figure A.7 (a) Variation in Surface Area of Cathode in Al-carbon battery



68

Figure A.7 (b) Variation in Surface Area of Cathode in Al-carbon battery



69

Figure A.8 Variation in concentration of HCl in Al-carbon battery



70

Figure A.9 Variation in Concentration of NaCl in Al-carbon battery



71

Figure A.10 Variation in Concentration of KOH in Al-carbon battery



72

Figure A.11 Variation in Surface area of anode in Al-copper battery



73

Figure A.12 Variation in Surface area of cathode in Al-copper battery



74

Figure A.13 Variation in Concentration of HCl in Al-copper battery



75

Figure A.14 Variation in Concentration of HCl in Al-copper battery



76

Fi A 15 V i i i C i f KOH i Al b



Figure A.15 Variation in Concentration of KOH in Al-copper battery

study of aluminium batteries as energy source r(1)

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