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LITHIUM-AIR BATTERIES: THE FUTURE OF ELECTRIC CARS
Kenneth McQuail (kjm108@pitt.edu)
INTRODUCTION: LITHIUM-AIR
BATTERIES AND THE FUTURE
In an effort to develop a more sustainable transportation
system, reduce dependence on fossil fuels, and meet the
demand for a clean and secure energy future, there has been
an increasing interest in the research and development of
electric cars [1]. While much progress has been made in the
development of electric cars in the last decade in particular,
there are still many barriers that must be overcome for
electric cars to become more efficient and economical when
compared to their internal combustion engine counterparts.
The largest obstacle faced by electric cars today is the
limited driving range caused by the current battery
technology [2]. My position is that engineers should invest
more time and energy into the research and development of
lithium-air batteries for electric cars. Lithium-air batteries
potentially offer a significant improvement over the lithiumion batteries that are currently being used, and they are the
innovation in electric car battery technology that will make
the widespread commercial use of electric cars possible, thus
reducing society’s dependence on nonrenewable resources
and creating a more environmentally friendly future [1].
Furthermore, engineers must pursue the lithium-air battery
because of their obligation for sustainable development, as
stated in the engineering code of ethics. This research paper
is a valuable assignment in a freshman engineering
curriculum because it forces students, such as myself, to
develop for themselves a perspective of the realities of the
career of engineering in the real world. As a prospective
engineer, I realize that eco-friendly technology is definitely a
need for the future. As such, I fully support further research
of lithium-air batteries for use in electric cars because of the
obligation of engineers and because lithium-air batteries will
make possible the widespread use of electric cars in the
future. Currently, the electric car industry is greatly
inhibited by the poor driving range of electric cars.
CURRENT STATE OF ELECTRIC CARS
While there are increasing numbers of electric cars on
the road every day, electric cars still face low driving ranges
that greatly hurt their sales and practicality. Popular electric
cars on the market today include the Tesla Roadster,
Mitsubishi i-MiEV, Nissan Leaf, and the Ford Focus
Electric, all of which use a lithium-ion battery. The
Mitsubishi i-MiEV, Nissan Leaf, and Ford Focus Electric
have an electric range, the maximum distance that can be
travelled on a single charge, of between 60 and 76 miles,
while the Tesla Roadster has a much higher range of 244
University of Pittsburgh, Swanson School of Engineering 1
October 30, 2012
miles [3]. While these ranges are drastic improvements in
the electric car industry, they are still too low for society’s
standards. This limited driving range promotes range
anxiety, the fear that a vehicle has insufficient range to reach
its destination and would thus strand the vehicle’s occupants
[2]. Because of range anxiety, many consumers choose not
to purchase an electric car, in favor of a traditional gasolinepowered car. Gasoline-powered cars commonly achieve
ranges of 300 miles per tank, which is much greater than the
average range of any electric car. Even if gasoline-powered
cars could not achieve such a superior range, they have the
ability to refuel at gas stations in a matter of minutes.
Recharging electric car batteries is a much more time
consuming process that takes multiple hours. As a result,
drivers of electric cars can only recharge their batteries at
their homes. While most drivers only drive between 40 to
60 miles per day, they still do not want to be limited by the
low range of electric cars in unusual cases or emergencies in
which they have to drive more than they anticipate. Also,
because of their low ranges, electric cars in their current
condition simply are not practical for many longer road trips
[2]. Electric cars can only achieve such low driving ranges
because of the poor capabilities of the lithium-ion batteries
that they currently use.
LIMITATIONS OF CAR BATTERIES
Lithium-ion batteries are the reason electric cars cannot
compete with the driving range achieved by gasolinepowered cars, mainly because of the low energy density
lithium-ion batteries have to offer. The driving range of
electric cars is largely determined by the battery’s energy
density (the amount of energy stored in a given system or
region of space per unit mass). Batteries with high energy
densities allow cars to achieve greater ranges [4]. The
lithium-ion batteries of the Tesla Roadster, Mitsubishi iMiEV, Nissan Leaf, and Ford Focus Electric have energy
densities ranging from 79 to 121 Wh/kg, with the battery of
the Tesla Roadster having the highest energy density [3]. In
comparison, gasoline has an energy density of 13,000
Wh/kg, over 100 times that of the Tesla Roadster [1].
Further development of the lithium battery, specifically the
development of the lithium-air battery, will make higher
energy densities possible.
THE DEVELOPMENT OF THE LITHIUMAIR BATTERY
Lithium batteries are currently the most advanced battery
technology, and the development of lithium batteries into the
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lithium-air battery has created a much more powerful battery
that will revolutionize the electric car. Much attention has
been given to lithium batteries because lithium metal has an
extremely high theoretical energy density (the highest of all
solid electrodes).
However, it is difficult to build
satisfactory rechargeable batteries using metallic lithium
because of shorting between electrodes during charging.
Lithium-ion batteries combat the problems faced by metallic
lithium batteries, and are widely used as a result. For these
reasons, lithium-ion batteries are the common choice for
batteries in electric cars, and they are used in the Tesla
Roadster, Mitsubishi i-MiEV, Nissan Leaf, and Ford Focus
Electric. Lithium-ion batteries can achieve energy densities
of 100 to 150 Wh/kg, which is limited by the low energy
density of available cathode materials [1], [5]. The principal
lithium-ion battery technologies used in electric cars are
lithium-nickel-cobalt-aluminum (NCA), lithium-nickelmanganese-cobalt (NMC), lithium-manganese spinel
(LMO), lithium titanate (LTO), and lithium-iron phosphate
(LFP) [2]. By replacing the heavy cathode metal with a
lightweight O2-breathing electrode, an energy density
projected to be as much as ten times that of lithium-ion
batteries can be achieved (1000 to 1500 Wh/kj). This is
called a lithium-O2 battery or, more specifically, a lithiumair battery if the O2 comes from the ambient air. Lithium-air
batteries have a theoretical energy density of 11,000 Wh/kg,
which approaches the 13,000 Wh/kg achieved by gasoline
[1], [5]. The extreme improvement in energy density offered
by the lithium-air battery is essential for progress in the
electric car industry.
for its use in electric cars. The first and principle
fundamental canon of the code of ethics for engineers states
that engineers must be dedicated to the protection of the
public health, safety, and welfare.
The professional
obligations of engineers takes this supreme notion one step
further in that engineers must also work for the advancement
of the safety, health, and well being of the community [6].
The welfare and well being of the community is not just
limited to society, but also includes the environment in
which society lives. Therefore, engineers are compelled to
both protect and advance the current state of the
environment. By advancing research and innovation of the
lithium-air battery in electric cars, engineers are actively
attempting to reduce the damaging effects cars have on the
environment, thus making for a better and healthier
relationship between society and its surrounding
environment for the future. This also satisfies the ethical
call for engineers to follow the principles of sustainable
development to protect the environment for current and
future generations.
Sustainable development is the
challenge faced by contemporary society to adequately
fulfill human needs for natural resources, energy,
transportation, and effective waste management as well as
protecting environmental quality and natural resources
essential for future development [6]. Advancements in the
electric car industry are an extremely necessary action for
the sake of sustainable development.
From an
environmental point of view, engineers are ethically required
to create and promote a healthy surrounding for all of
society, as well as to attempt to achieve the lowest possible
consumption of raw materials and energy and the lowest
production of wastes and pollution. Furthermore, engineers
should reject any commitment involving the unfair or
unnecessary damage of human surroundings and the
environment [7]. The pollution created by cars is extremely
damaging to the environment as well as unnecessary.
Development of the lithium-air battery is an extremely
necessary step to greatly reduce this pollution. Besides
pertaining to the engineering community as a whole,
research of problems faced by engineers, such as the
problem faced by the electric car industry, is particularly
valuable to prospective engineers at the freshman level.
VALUE OF LITHIUM-AIR BATTERY
The higher energy density of the lithium-air battery
would drastically improve the driving range of electric cars,
thus revolutionizing the electric car industry. Although there
is limited experimental data concerning lithium-air batteries
in electric cars because of the current state of the research
and knowledge of lithium-air batteries, the extremely high
energy density of lithium-air batteries implies that there
would definitely be improvement in the range of electric
cars, and that the improvement could be extreme. Because
of the immense impact lithium-air batteries could potentially
have on electric cars, it is essential that engineers devote
more time and energy to the research and development of
lithium-air batteries. In fact, engineers have an ethical
obligation to further research lithium-ion batteries because
of the great positive effect they could have on society and
the environment.
EDUCATION AND THE VALUE OF THIS
ASSIGNMENT
From an educational point of view, it is imperative that
prospective engineers are completely aware of why they are
studying to become an engineer; engineering students need
to understand the realities of their field of study so that they
are certain it is right for them. The field of engineering is a
difficult and time-consuming process, and students should
not waste time and money studying to become an engineer
if, in the future, they will decide that it is not their correct
path. Therefore, the assignments engineers must complete
ETHICS: AN OBLIGATION TO
DEVELOP THE LITHIUM-AIR BATTERY
From an ethical point of view, engineers are obligated to
research and make improvements on the lithium-air battery
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in their curriculum must correctly prepare them for the truth
of what their field of engineering and a career within that
field will encompass. This writing assignment in particular
is valuable because it does just that and forces students to
learn about and research an engineering topic that interests
them. Students learn in a more enjoyable and relevant
manner when they must study real world examples and
problems and when they must draw their own conclusions
[8]. By researching real world problems faced by engineers,
students gain valuable insight into the realities of an
engineering career. All engineering students should be
required to take a stance on an important and relevant
engineering issue in their freshman year because of what
they will learn about themselves.
Such glimpses of
examples of engineering in the real world allow students to
decide if that particular type of engineering, or engineering
in general, is the career they will want to have in the future.
This research assignment is important and useful because it
gives students some perspective into the complicated and
intensive field of engineering. Personally, I have gained
from the research I have done in that I now have some
perception of the realities of an engineering career, and I
have realized the state of the environment and the electric
car industry. An improvement in the driving range of
electric cars, as enabled by the lithium-air battery, will make
for a more environmentally friendly future which affects all
of society, including myself.
partially created my awareness for our effect on the
environment, took a step to lessen my family’s individual
impact on the environment by purchasing a Toyota Prius. A
Toyota Prius is a hybrid electrical vehicle, which combines
an internal combustion engine with an electric motor [4].
While the Toyota Prius did increase our miles per gallon (to
about 50), it was still dependent on gasoline. Also, I was
extremely disappointed by the limited range of the car when
it was running on just the electric battery. I realized that
there was still much work to be done to improve electric cars
and their driving range. As a future engineer, I realize that
the research and development of electric cars, particularly
the electric car battery, is an extremely necessary step in
enabling a future where electric cars are commonly used and
society lives in a much more environmentally conscious
manner. Furthermore, I realize that engineers must devote
more time and effort into the development and innovation of
lithium-air batteries simply because of the overall goal of
engineers of sustainable development. As a future engineer,
I will be conscious of my purpose in society and my
responsibility to protect and ameliorate the condition of the
environment. Also, I see the importance of this writing
assignment because it has forced me to try to understand
some of the real problems faced by engineers. The research
I have done has reinforced my pursuit of a career in
engineering, and it has allowed me to form my own
conclusion concerning a relevant problem faced by
engineers today. I know that the research and development
of lithium-air batteries is the answer to a clean future that
finally includes the widespread use of electric cars.
WHY I CARE
The current energy crisis and the negative impact society
has on the environment has created a dire situation for the
future, and I am greatly concerned with this issue because I
know it will affect all of society and myself. Renewable
energy sources must be pursued to avoid, and eventually
end, dependence on nonrenewable resources, particularly oil.
While many people believe that they alone cannot change or
largely affect a problem of this magnitude, I believe that
individual people can significantly impact the problem by
simply making changes in their everyday lives. People must
become more environmentally friendly if they want to put an
end to the energy crisis and to create a better and healthier
environment for the future. As a young member of society
who will personally experience the results of society’s
negative impact on the environment in the future, I see no
other option but to start implementing change immediately
to create a better tomorrow. I see the advancement of
electric cars as a way to end the energy crisis and create a
more environmentally friendly society. In recent years, it
seems to have become common knowledge that cars have
high CO2 emissions, which pollute the environment. In
particular, CO2 emissions harm the ozone layer, which
creates global warming. By switching from gasolinepowered cars to electric cars, society can greatly reduce its
negative impact on the environment. My father, who has
CONCLUSION: THE NEED FOR
RESEARCH OF LITHIUM-AIR BATTERIES
Further research of lithium-air batteries and their
implication in electric cars will considerably increase the
driving range of electric cars, thus enabling an
environmentally friendly future. Electric cars today are
limited by their lithium-ion batteries, which have relatively
low energy densities and therefore low ranges. Lithium-air
batteries can achieve much greater energy densities,
allowing electric cars to achieve greater ranges. The use of
lithium-air batteries in electric cars will reduce the negative
impact society has on the environment, leading to a clean
and secure energy future for society, engineers, and myself.
Because of this, engineers must feel an ethical obligation to
the development of lithium-air batteries. Additionally,
assignments such as this one provide prospective engineers
with essential insight into real world engineering and force
them to make decision concerning their own engineering
career. My research of lithium-air batteries has strengthened
my personal choice of engineering as my career. More
importantly, the research and development of lithium-air
batteries is a necessity for the overall future of society.
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REFERENCES
[1] F. Alamgir, J. Cho, M. Liu, S. Park, M. Song (2011,
November 22). “Nanostructured electrodes for lithium-ion
and lithium-air batteries: the latest developments,
challenges, and perspectives.” Materials Science and
Engineering: R: Reports. (Online Article).
http://www.sciencedirect.com/science/article/pii/S0927796X
11000593
[2] A. Dinger, R. Martin, X. Mosquet, M. Rabl, D. Rizoulis,
M. russo, G. Sticher (2010). “Batteries for Electric Cars.”
The Boston Consulting Group. (Online Article).
http://www.bcg.com/documents/file36615.pdf. pp. 1-3
[3] “Increasing Energy Density Means Increasing Range.”
(2012). Tesla Motors. (Online Article).
http://www.teslamotors.com/roadster/technology/battery
[4] R. Padbury, X. Zhang (2011, May 15). “Lithium-oxygen
batteries-Limiting factors that affect performance.” Journal
of Power Sources. (Online Article).
http://www.sciencedirect.com/science/article/pii/S03787753
11001108
[5] J. Garche, B. Scrosati (2010, May 1). “Lithium batteries:
Status, prospects and future.” Journal of Power Sources.
(Online Article).
http://www.sciencedirect.com/science/article/pii/S03787753
09020564
[6] “NSPE code of Ethics for Engineers.” National Society
of Professional Engineers. (Online Article).
http://www.nspe.org/Ethics/CodeofEthics/index.html
[7] (2001). “The WFEO Model Code of Ethics.” World
Federation of Engineering Organizations. (Online Article).
http://www.wfeo.net/about/code-of-ethics/
[8] E. Byrne (2012). “Teaching engineering ethics with
sustainability as context.” Emerald Group Publishing
Limited. (Online Article).
http://www.emeraldinsight.com/journals.htm?articleid=1704
2044&show=abstract
ACKNOWLEDGEMENTS
I would like to first thank my father, Christian McQuail,
for opening my eyes to the negative effect society has on the
environment and for taking a step to lessen this by
purchasing a hybrid electric vehicle. I would also like to
thank my fellow engineering students and friends, Benjamin
Dobies and Jacob Reck, for helping me along the way with
my research paper, primarily concerning formatting and
requirements.
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