Conference Session: A4
Paper #173
Disclaimer—This paper partially fulfills a writing requirement for first year (freshman) engineering students at the University
of Pittsburgh Swanson School of Engineering. This paper is a student, not a professional, paper. This paper is based on publicly
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THE LITHIUM-OXYGEN BATTERY AND THE AUTOMOTIVE INDUSTRY: A
ROAD TO SUSTAINABILITY
Steven Corcoran, [email protected], Mahboobin 4:00, Tyler Weinstein, [email protected], Mahboobin 4:00
Abstract--As the search for unique and more efficient power
surges forward, discovery and innovation abound. Batteries
are becoming lighter, smaller, and quicker to charge. One
specific innovation is the lithium-oxygen battery: this battery
is distinguishable in its ability to be recharged many times
without decomposing. While this battery is still being tweaked
to optimize energy efficiency, it has potential in the
automotive industry to create more efficient electric vehicles.
One of the most enticing features of the lithium-oxygen
battery for engineers and researchers is its power output
relative to its mass (gravimetric energy density), which is
higher than any other battery’s. Lithium’s low mass, in
conjunction with oxygen gas, contribute heavily to the
gravimetric energy density of 1700 Wh/kg. This means, firstly,
that a lithium-oxygen battery can produce a much greater
output than conventional batteries of the same weight.
Alternatively, lighter batteries can be created which would
result in lighter electric vehicles, a current goal for
automakers. Both options will allow the automotive industry
to become more efficient in terms of energy expenditures,
making electric vehicles more economically competitive.
However, before this technology can become commercially
viable, chemical and environmental obstacles which hinder
the lithium-oxygen batteries’ efficiencies must be overcome.
Some obstacles, such as the formation of side products like
lithium carbonate and lithium hydroxide, disallow the battery
from outputting proper potentials. Another issue is the overall
impact of the lithium-oxygen battery on the environment,
which is important for assessing the viability of the
electrochemical cell. To overcome this obstacle, the
European STABLE project is working on a Life cycle
assessment for the lithium-oxygen battery to assess its
impacts on the environment. Overall, this burgeoning
technology has a bright future, leading the world to a greener
tomorrow.
Key Words–Anode, Cathode, CO2-eq, Electrocatalysts,
Gravimetric energy density, Life cycle assessment, Side
reactions
EFFICIENCY IN BATTERIES: DERIVING
TOMORROW’S ENERGY
University of Pittsburgh, Swanson School of Engineering
Submission Date: 03.31.2017
In the 21st century, sustainability is an idea that is tossed
around ad nauseam. Sustainability is broadly defined and can
have many meanings. Here we are defining it as the efficient
management of finite resources to allow for consumption
without depletion. In regards to our technology, the goal
within sustainability is to decrease global dependence on
fossils fuels while finding alternative avenues to satiate the
world’s energy needs. Current models of electric vehicles
incentivize some individuals; however, the weight of the
vehicles and their limited range make them impractical for
many consumers. The lithium-oxygen battery has many
qualities, enumerated below, which allow it to compete better
with the internal combustion engine while at the same time
having the ability to outperform the lithium-ion battery in
current electric vehicles.
Since the proliferation of electricity and power-based
technology, the use of batteries has become much more
prevalent. From large batteries with immense storage
capacities to nanobatteries that function on a molecular level,
the diversity among batteries is phenomenal [1][2]. Today,
innovations are occurring in an attempt to make popular
battery models more sustainable. These innovations result in
allowing suppliers to use less resources in battery production
or in changing the batteries’ chemistry to lower the necessary
recharge energy. Recognizing the necessity to make an
efficient, lightweight battery that is, at the same time,
economically competitive is an ongoing struggle for
researchers and businesspeople alike. However, other
considerations must also be made when assessing the
sustainability of the technology.
Among other things to be considered are disposal
procedures and toxicity of byproducts. The environmental
implications of batteries do not end when the battery dies, but
rather extend far into the future after the death of the battery.
The analyses of the environmental impacts are done through
a holistic Life cycle assessment of the technology. Though the
battery may be able to efficiently power a car, its current CO 2
outputs make it less eco-friendly than desired.
Since the lithium-oxygen batteries are still in their early
stages of research and development, some of these important
fundamentals regarding batteries will remain unaddressed.
However, research being done on the lithium-oxygen battery
will lead to groundbreaking results in the near future, which
Steven Corcoran
Tyler Weinstein
will be led by the most efficient battery modern science can
provide [3].
The innovation of electric vehicles powered by lithiumion batteries was astounding and revolutionary. At the same
time, it merely paved the road for future sustainable energy
projects, one of which is the lithium-oxygen battery. Through
this research, the world can begin to slowly divest from
reliance on gasoline and, in turn, change the way the world
consumes energy and finite resources. On the frontier for
battery innovation, there is still much to explore; however, the
advancements of the past make it much easier for researchers
to develop the batteries of the future.
CONVENTIONAL BATTERIES
The History and Progress of Batteries
The principle of the battery has been around for
centuries, beginning with the capacitor batteries of the late
1700s and leading up to today’s lithium-ion batteries. The
creation of the first battery began with one of Benjamin
Franklin’s experiments. Franklin had been experimenting
with the properties of linked capacitors, devices containing
two parallel, conducting plates which allow for the storage of
electrical charge [4]. While Franklin’s capacitors had the
ability to store charge, these capacitors would begin to
discharge the moment charging came to a stop. After a few
seconds, the capacitors would lose all electricity it had stored,
preventing these capacitors from producing a stable current
necessary for powering devices. This left the earliest
‘batteries’ without a practical purpose during that era. Around
fifty years later Alessandro Volta, an Italian physicist,
expanded upon Franklin's idea. Volta discovered a way to
produce a relatively stable charge by stacking zinc and copper
discs in brine solution, producing 0.76 Volts [4]. Volts are
essentially the amount of energy stored in each charged
particle. A charged particle is simplistically defined as a
positive particle (a proton) or a negative particle (an electron)
which each carry a charge with magnitude 1.602E-19
Coulombs. Volta’s version of the battery had the ability to
hold its charge for extended periods of time, something
Franklin’s capacitor batteries were incapable of.
Later models of batteries include the alkaline and the
zinc-carbon battery. These modern batteries produce a
reliable charge and are relatively compact. The alkaline and
zinc-carbon batteries stem from the family of batteries known
as primary batteries. Primary batteries are electrochemical
cells that “cannot be easily recharged after one use” [5]. As a
result, these batteries are primarily used for powering small
electronics, like flashlights, and other devices that do not
require a large power output. These batteries are
commercially available in supermarkets. While the primary
battery is able to produce a reliable charge, in many instances,
it is not substantive for devices which need to be recharged.
As a result, the lithium-ion battery was developed during the
1980s to power rechargeable devices.
For its time, the lithium-ion battery was revolutionary.
Today, it is prolific in handheld devices such as cellphones
and is the battery which currently powers electric and hybrid
vehicles. This type of rechargeable battery bases its success
on the properties of the element lithium. On the periodic table,
lithium is the lightest metal with one of the largest
electrochemical potentials, a unit of energy per mass [4]. This
means that the lithium-ion battery, with the same weight as a
primary battery, will produce a voltage several times greater
than that of common primary batteries.
Systematic Functioning of Batteries
While the multitude of available batteries covers a broad
range of applications and advantages, their inner workings are
all fundamentally similar. The concept of the battery has been
explored and improved upon for over a hundred years, all on
the basis of one concept: electrochemistry. Electrochemistry
is the chemical process by which electrons flow to produce an
electric current. After all, the battery in its most basic form is
simply a chemical reaction resulting in the movement of
electrons. The first part of electrochemistry always begins
with a oxidation-reduction reaction, which involves a change
in oxidation state governed by a change in the number of
electrons. Through these processes, for example, a compound
with excess electrons (negative charge) could confer this
charge to a neutral compound via the transfer of electrons.
After the reaction, the reactants will have a different total
charge than beforehand.
As shown below in Figure 1, batteries are made up of
three components: anode, cathode, and electrolyte. The anode
is the negatively charged portion of the battery that is
oxidized, meaning it loses electrons. The cathode is the
positively charged end that is reduced, meaning it gains
electrons. The electrolyte is the medium that allows the flow
of electrons between the two charged ends.
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published a paper discussing a “novel rechargeable Li/O 2
battery” [8]. Their model of the battery was rife with
inefficiency and would never be usable in a commercial
market; however, it opened the door to future research efforts
which would try to improve the viability of the lithiumoxygen battery. The production of what was thought to be a
purely theoretical cell proved to the scientific community that
research efforts could one day make this battery
efficient. Throughout the past two decades, research has
become increasingly active on the topic of lithium-oxygen
batteries. Besides its high energy capacity, another enticing
feature of the lithium-oxygen battery is that it is rechargeable,
unlike other commonly used batteries—like the zinc-carbon
(alkali) battery [4].
FIGURE 1 [6]
The image identifies the batteries components as well as
the flow of electrons from the anode
For example, the zinc-carbon battery contains a zinc
anode and graphite cathode [4]. In this reaction, the zinc
anode is oxidized, while manganese oxide is reduced at the
graphite (carbon) cathode.
Anode Reaction:
Zn(s) → Zn (aq) + 2e
2+
-
(1)
Cathode Reaction:
Deriving Power From the Lithium-Oxygen Battery
2MnO (s) + 2NH Cl(aq) + 2e → Mn O (s) +2NH (aq) +
2
4
H O(l) + 2Cl [7]
2
-
-
2
3
3
The charge and discharge phase of the lithium-oxygen
battery are marked by lithium-based reactions which store—
then disperse power. The ideal reactions for the battery are as
follows:
(2)
The second part of electrochemistry occurs as a result of
the reduction-oxidation reaction. Every second, while this
reaction occurs within the zinc-carbon battery, excess
electrons are being produced and begin to “build up at the
anode” [6]. This buildup of charge at the anode creates a
potential difference, also known as a voltage, between the
anode and the cathode due to excess charge at the anode and
a lack of charge at the cathode [6]. Since the tendency for
electrons is to repel from like charges (other electrons), the
excess electrons flow away from the anode towards the
cathode. This flow is called the electrical current, which is
used to power many devices used today. Similar
electrochemical systems are used in laboratory models of the
lithium-oxygen battery, with the goal of maximizing voltage
output from the battery.
Li + O + e → LiO ,
+
-
2
(3)
2
followed by
LiO + Li + e → Li O
+
2
-
2
(4)
2
or, alternatively
2LiO → Li O + O [9].
2
2
2
(5)
2
These reactions occur during charging. Reduction
occurs in the first two equations above. During reduction, an
electron binds to a chemical and adds a negative charge to the
species. The reduction of Li happens during the charging
phase of the battery cycle. Conversely, oxidation of lithium
occurs during the discharge phase of the battery cycle. Atoms
and ions lose electrons via oxidation. The loss of two
electrons from a lithium peroxide molecule, as shown below,
is an example of oxidation. This is also the most relevant
oxidation reaction in the lithium-oxygen battery.
+
WHAT IS THE LITHIUM-OXYGEN
BATTERY?
Humble Beginnings
The lithium-oxygen battery is a theoretical
electrochemical cell that utilizes a lithium metal anode and
inert (graphite or platinum, usually) cathode—with oxygen,
to store and release energy, which could be used to power
devices such as cell phones and electric vehicles. Inert
substances are substances that do not play a major role in the
overall electrochemical reaction in a battery. While the idea
for the lithium-oxygen battery has been around for decades,
scientists have had difficulty overcoming its limitations,
which will be discussed later. Though researchers covet the
lithium-oxygen battery for its theoretically high energy
capacity, the road to producing a viable cell has been long and
arduous. The pursuit for innovation of this electrochemical
cell picked up in 1996 when researchers Abraham and Jiang
Li O → 2Li + O + 2e [10].
2
2
+
2
-
(6)
As previously mentioned, all of these reactions are
lithium based. This is due to an important property in
elements: ionization energy. Some elements have a higher
tendency to ionize than others. The elements that have an
intense proclivity to ionize are the alkali metals, in the first
period of the periodic table of elements. Elements in the first
period ionize easily due to their low ionization energy, the
amount of energy required to remove an electron from an
atom’s electron cloud. For lithium, the first ionization energy
is approximately 513 kJ/mole [11]. Another useful feature of
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lithium is its low mass which, when coupled with a nonaqueous cathode, has the ability to create lightweight
batteries.
results about how to optimize the power output of the lithiumoxygen battery. Much of this research has been focused on
extending the lifetime of the lithium-oxygen battery, in terms
of cycles of charging. According to Luo et al., a battery with
a lifetime of 300,000 miles and range per charge of 500 miles
needs a cycle life of at least 600 cycles [13]. A sustainable
lithium-oxygen battery with high cycling life is necessary
because the battery can be replaced less often. Replacing
batteries less often allows producers to conserve resources
and products, avoiding overconsumption. Luo et al. have
created a lithium-oxygen battery which can withstand 800
cycles and uses sulfolane, a compound which contains a
“five-membered ring structure of cyclic carbonates” that is a
component of many electrolytes used in lit hium-ion batteries
[13]. The trials for this lithium-oxygen battery yielded an
average energy efficiency of almost 75%, which means the
battery is highly efficient, at a constant current density of
1000 mAh g [13]. Since Abraham et al. produced the first
lithium-oxygen battery with poor cyclic performance,
researchers have worked to greatly improve the quality of the
lithium-oxygen battery after many cycles [8] [13].
FIGURE 2 [11]
Graph of specific energy as a function of battery type
-1
The figure above is a visualization of the comparison
between different types of batteries. Along with this graph are
estimations of how far the car could travel based on the
“minimum specific energy” of each battery type [12]. The
prices, in USD kW h- 1, for batteries which have not been
developed, represent the goals of the US Advanced Battery
Consortium [12]. This diagram illustrates why the lithiumoxygen battery, in some regards, is a sustainable solution to
gasoline consumption. Its specific energy rivals that of the
traditional combustion engine, and electric vehicles are
expected to triple in range from their current state after
research and development are complete [12]. The
electrification of day-to-day vehicles will help alleviate
demand for gasoline and allow alternative sources of energy
to rule the roads.
Catalysts: Examples and Functionality
An important sustainable topic in electrochemistry is
rate of reaction. With respect to industry, the rate at which a
reaction occurs defines how quickly a material can be
commercially outputted. The process of catalyst
implementation is a sustainable practice as it conserves
energy by increasing the rate of reaction. In general, catalysts
do not affect the overall reaction that occurs. Rather, catalysts
work to create alternate pathways for reactants. This has the
effect of lowering the activation energy required for a reaction
to occur. Activation energy is a threshold of energy which a
system must acquire before a reaction can occur. Lowering
activation energy via catalysts results in a faster rate of
reaction.
Presently, there are numerous catalysts which could
function well in the lithium-oxygen battery. Therefore, there
is plenty of research which delves into the effects of specific
catalysts on the chemistry of the lithium-oxygen battery.
According to Wu et al., iron oxide could serve as a strong
electrocatalyst because it limits dangerous overpotentials
[14]. An overpotential is the difference between the potential
(voltage), determined theoretically by a reduction-oxidation
reaction, and the potential measured from an experimental
reaction. This chemical species exemplifies how catalysts can
be introduced into a system to make the system more
sustainable in terms of energy consumption. Wu et al. found
that iron oxide works as an electrocatalyst to improve
conductivity in the electrochemical cell, but also that it
limited the contact between carbon and Li2O2, which
decreased the presence of Li2CO3 in the cell [14]. The
introduction of catalysts, like Fe2O3, into electrochemical
cells have profound effects on the chemistry, voltage, and
current density in the battery. In the figure below, Fe 2O3
INNOVATIONS OF LITHIUM-OXYGEN
BATTERY
Cyclic Performance
The road to a successful and sustainable lithium-oxygen
battery begins with taking necessary steps to ensure that the
battery can survive for many cycles of charging, discharging,
and recharging. Research on the lithium-oxygen battery only
picked up in the mid-1990’s after the introduction of a
working model by Abraham et al. [8]. With regard to cycling
research, improving cycling for any battery is important as it
lengthens the lifetime of the battery itself and the chemicals
within. Extending the lifetime of the lithium-oxygen battery
would lower the price of the electrochemical cell, allowing it
to be more competitive and accessible to consumers.
As noted previously, there is an abundance of chemical
barriers which interfere with the potential efficiency of the
lithium-oxygen battery [3]. However, research and
development in the last two decades have yielded various
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supported by Vulcan XC-72 carbon (XC), not only improved
current density (a), but also lowered charge voltage (b),
increased discharge voltage (c), and allowed Li2O2 to remain
as the main product of the discharge phase (d) [14]. More
rigorously, the charge voltage of the battery decreased to 4.01
V, which was more than four tenths of a Volt lower than with
just a XC carbon cathode [14]. Lowering the charge voltage
allows the battery to more efficiently expend energy. Another
important aspect of this catalyst is its ability to safeguard the
structural integrity of the cell, with cycling ranges over 50
cycles at a current density of 500 mAh g-1 [14]. Wu et al.
conclude that high cycling stability of Fe2O3 as well its high
charge voltage make it an important catalyst for the future of
a sustainable lithium-oxygen battery.
While sustainability incentivizes some, economic
circumstances cause many to overlook the benefits of
expensive technologies. On a single charge, an electric
vehicle is limited to a range of 100 miles [15]. In order to
compete with traditional vehicles, capable of traveling over
300 miles, electric vehicles must have a comparable range. To
understand why this is the reality, a proper analysis of the
batteries within electric vehicles is required. Since batteries
waste 10% of the fuel’s energy compared to 85% in
combustion engines, batteries cannot inherently be the issue
[15]. The prime motivation for the continuation of research
on electric vehicles’ batteries has been the greater energy
efficiency threshold potential of batteries. The lithium-ion
battery, adopted by a supermajority of electric vehicles, has
championed an unrivaled gravimetric energy density ever
since its inception during the 1990s [3]. Higher gravimetric
energy densities translate to more considerable power
outputs; however, an internal combustion engine of similar
proportions to a lithium ion battery creates a power output 60
times greater than the lithium ion battery [15]. The
competitiveness of electric vehicles is stymied by the
deficiency of their power sources. In addition, the lithium-ion
battery’s minimal power output requires the weight of these
batteries to comprise 15% of the total weight - in some
vehicles - to substantially propel the vehicle [16]. Unless a
technological breakthrough exponentiates its gravimetric
energy density, the lithium-ion battery will continue to
forestall the forthcoming of electric vehicles.
A New Spark for Electric Vehicles
FIGURE 3 [13]
Various graphs measuring data from experiments
involving the effects of XC and Fe2O3 on the
electrochemistry of the lithium-oxygen battery
Many alternative solutions have been proposed to
ameliorate or bypass their inefficiencies of lithium-ion
batteries in electric vehicles. One such solution is the lithiumoxygen battery with an unrivaled practical gravimetric energy
density of 1700 Wh kg-1, approximately 6 times greater than
that of the lithium-ion battery [10]. Because its gravimetric
energy density leads to a growth in power output, the lithiumoxygen battery allows for lighter car batteries. The
lightweight nature of the lithium-oxygen battery would
reduce an electric vehicle’s total weight [17]. A direct result
of reducing a vehicle's weight is an increase in driving range.
While the lithium-oxygen battery’s gravimetric energy
density is still fractional to that of traditional combustion
engine vehicles, it would begin to bridge the mileage gap
between traditional combustion vehicles and electric vehicles.
THE LITHIUM-OXYGEN BATTERY’S
POTENTIAL IN THE AUTOMOTIVE
INDUSTRY
Where Electric Vehicles Stand in the Automotive
Industry
The rapid consumption of finite and nonrenewable
resources beckons researchers to innovate methods for energy
expenditure. The manifestation of this research in the
automotive industry is the invention and innovation of electric
vehicles, which serve as an alternative to the internal
combustion engine of traditional vehicles. While researchers
have been successful in the creation of a functioning electric
vehicle, their initial motive for designing these vehicles has
yet to be fulfilled.
In order for electric vehicles to outpace traditional
combustion engine vehicles in ubiquity, electric vehicles must
first appeal to consumers. For consumers, the present state of
the electric vehicle stands short of offering a more attractive
option in contrast to traditional combustion engine vehicles.
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While energy efficiency of the lithium-oxygen increases in
the presence of higher humidity, the charge voltage and the
discharge voltage amounts become highly variable and more
unpredictable, due to the varying humidity levels and
interfacial chemical reactions [17]. This is further elucidated
by the following figure:
FIGURE 4 [3]
Graph of the theoretical and practical gravimetric
energy densities for rechargeable batteries
LIMITATIONS OF THE LITHIUMOXYGEN BATTERY
What Are Some Limitations to the Lithium-Oxygen
Battery?
FIGURE 5 [17]
Energy Efficiency as a function of Relative Humidity
(Inner figure represents energy efficiency as a function of
the number of cycles performed)
There remains a myriad of issues which prevent the
lithium-oxygen battery from being profitable, or even usable,
in today’s society. The common theme of many of these
shortcomings is the non-ideal conditions which arise from the
chemical composition of Earth’s atmosphere. Among these
issues is the presence of CO in the air. While carbon dioxide
makes up a nominal amount of the planet’s atmosphere, it still
has a role in the functionality of the lithium-oxygen battery
and must be considered. Below is a possible side reaction
which can occur between important reactants in the battery
and CO :
This figure exemplifies the effects of humidity on the
energy efficiency and cycling of the lithium-oxygen battery.
Cycling in a battery is the process of charging and discharging
the battery; one cycle is one charge and one discharge of the
battery. The presence and persistence of unwanted side
products which interfere with the main reactions in the battery
make it impossible to produce a reliable, consistent voltage.
The inner figure illustrates the energy efficiency of the
lithium-oxygen battery as a function of the number of cycles
the battery has undergone [17].
Water is seen to cause a greater detriment to the lithiumoxygen battery than carbon dioxide due to its variability in the
atmosphere at different humidity levels. The side reactions
which occur in the electrochemical cell due to the presence of
water are as follows:
2
2
4Li + O + 2CO → 2Li CO
2
2
2
(7)
3
2Li O + 2CO → O + 2Li CO [16].
2
2
2
2
2
3
(8)
As evidenced above, neither the raw lithium nor its
compounds are immune to the effects of CO contamination.
Here we see the double-edged sword associated with the
reactivity of lithium. The low ionization energy of lithium
also causes it to react quickly with other species. In the case
above, CO , which is a minor constituent of atmospheric air,
still has a notable effect on battery efficiency. It is therefore
necessary for a functional and practical lithium-oxygen
battery to safeguard against CO and the side reactions created
due to carbon dioxide. This is one issue which has not been
fully resolved through current research efforts.
Another compound that needs to be considered when
creating a functioning lithium-oxygen battery is water. Water
manifests itself in the atmosphere in the form of humidity.
Humidity can vary wildly depending on where it is measured.
2
2Li O + 2H O → 4LiOH + O
2
2
2
2
4Li + 4e + O + 2H O → 4LiOH [17].
+
-
2
2
(9)
(10)
2
The equations above show the adverse effects of
lithium’s reactivity with water. All lithium-based species in
the battery are susceptible to water based reactions. Water’s
presence in the atmosphere, in the form of humidity, makes
these side reactions virtually inevitable.
Since both lithium ions and lithium compounds undergo
side reactions with water, a viable lithium-oxygen battery
must sufficiently protect the battery from water. Furthermore,
2
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as humidity becomes very high, another possibility is the
dissociation of LiOH in excess water:
LiOH → Li + OH
+
-
important to accurately measure the overall impact the battery
will have on the environment.
Furthermore, projects such as STABLE (STable highcapacity lithium-Air Batteries with Long cycle life for
Electric Cars) are working to improve the lifelong capabilities
of the lithium-oxygen battery [21]. Among the goals of this
project—sponsored by the European Commission—are to
“[innovate the] anode, cathode, electrolyte materials and
technologies” [21]. These methodologies are going to be
combined with the selection of proper catalysts to optimize
power output. Emphasis will also be put on limiting CO 2
output of the lithium-oxygen battery to lessen its
environmental impact [21]. Ultimately, improvements to the
“lifetime and cyclability” of the lithium-oxygen battery are
the expectations of STABLE and the European Commission
[21].
At this point, STABLE research has produced lithiumoxygen cells with a CO2-eq output of 300 grams per kilogram
[20]. The goal set by the EU—95 grams CO2-eq per
kilogram—illustrates that the lithium-oxygen battery still
must undergo significant alterations before it can be
commercially produced [20]. CO2-eq is a common unit used
to describe the quantity of various greenhouse gases in a
succinct and organized manner, by comparing it to the
equivalent amount of carbon dioxide needed to make the same
“global warming impact” [22]. As engineers worldwide push
for greater regulation of pollutants, more sustainable strides
must be made on the part of researchers to reduce the CO2-eq
emission rate of the lithium-oxygen battery. While future
recycling innovations could eliminate 10% of the climate
impact, innovations cannot falter if a functional model of the
lithium-oxygen is to be produced [20].
(11)
To this effect, the battery should be able to dispose of
unwanted byproducts, such as LiOH, before they can inhibit
the functionality and voltage output of the cell.
Why Do These Limitations Exist?
Though the lithium-oxygen battery has many design
barriers which prevents it from being efficient in its current
form, there are many commonalities between these
limitations. The fact that our atmosphere contains more than
just oxygen for the battery to react with is one of the main
issues [3] [17]. As seen previously, this leads to a buildup of
lithium carbonate, Li2CO3, and lithium hydroxide, LiOH, in
the cell. These chemicals are undesirable, as they cause
unwanted side reactions which the battery cannot
accommodate for. According to Tan et al., a functioning
lithium-oxygen battery requires a cathode which can function
properly in the presence of LiOH and Li2O2 [17]. This is the
only way for the lithium-oxygen battery to be able to
compensate for the humidity present in the atmosphere.
Another reason that limitations of the lithium-oxygen
battery exist is due to the high reactivity of lithium. All of the
alkali metals are highly reactive due to their electron
configuration. These elements all have one valence electron,
which is easily removed from their respective electron clouds
to form bonds in compounds or to create ions [19]. The
electron configuration in lithium, allows it to be easily ionized
and react easily in the presence of many common atmospheric
compounds, like water and oxygen [19]. The reactivity of
lithium is not something that can be changed easily; therefore,
the types of compounds which interact in and around the
battery must be either restricted or accommodated, as noted
above.
ATTEMPTS TO DRIVE HOME
SUSTAINABLE SOLUTIONS
One important facet of the emerging lithium-oxygen that
has yet to be completely addressed is its environmental
implications. Due to the lack of a fully functional model of
the lithium-oxygen battery, it is currently impossible to note
the exact environmental impact of the lithium-oxygen battery.
A rigorous Life cycle assessment has been created for the
lithium-oxygen battery by Zackrisson et al. [20]. With regard
to lithium-oxygen batteries, chemical cells are “analyzed
from cradle to grave” [20]. To this effect, every step between
the cultivation of raw materials and the recycling process is
considered in the Life cycle assessment. Though meticulous,
the analysis of the lifetime of the lithium-oxygen battery is
FIGURE 6 [14]
Flowchart of the theoretical outline of the LCA for the
lithium-oxygen battery
PROMISING PATHWAYS
At times the humblest approach to analyzing a
technology’s capabilities is by reflecting on how far it has
come since initial research efforts. While the lithium-oxygen
has undergone considerable research for the last two decades,
each innovation leads to more logistical issues. This is
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Tyler Weinstein
[3] P. Adelhelm. “From lithium to sodium: cell chemistry of
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accommodate atmospheric levels of carbon dioxide and water
[17] [18]. Furthermore, consensus surrounding what catalyst
should be used in the battery has not been reached. While
there’s potential for this battery in the automotive industry,
integration is still years from becoming a reality. Though
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Regardless of current setbacks, it is imperative to note
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vehicles today, despite its progress in research and
development. With the highest measured gravimetric energy
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potential pathways for the lithium-oxygen battery diverge
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batteries which allow for a greater distance to be covered by
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vehicles of tomorrow.
Accompanying these possible futures for the technology
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as much of a benefit to the environment as a detriment.
Current research is being conducted to reduce the battery’s
carbon footprint, though this process has proven itself
burdensome and slow. Through gradual changes, the world
becomes more adept at utilizing and conserving its finite
resources. In its current state, the battery is not viable from an
environmental or economic standpoint. However, the future
is bright and research efforts are abundant. Hopefully, in the
next decade, the world will see a functional lithium-oxygen
battery which can be incorporated into electric vehicles.
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ACKNOWLEDGMENTS
Writing this paper has been a harrowing process. It could
not have been done nearly as effectively without the sage
review and advice of a few notable people. We’d like to
acknowledge Julianne McAdoo for reviewing our paper and
offering suggestion for revision. We’d also like to recognize
Janine Carlock for ensuring the clarity and effectiveness of
our writing. Additionally, we’d like to thank our friends
Navdeep Handa and Brian Gentry for looking over our
abstract and offering criticisms. We would also like to extend
our gratitude to Iman Basha, our conference co-chair, and
Mark Jeffrey, our conference chair, for assisting us heavily
throughout the writing process. Without their inspirational
insights and well-thought criticisms of our paper, it would not
have been as successful of a paper.
ADDITIONAL SOURCES
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L. Otaegui. “Performance and long term stability of a liquidtin anode metal-air solid electrolyte battery prototype.”
Electrochimica Acta. 2016. Accessed 01.08.2017.
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