Green chemistry is a revolutionary approach to chemical design and manufacturing that aims at minimizing the usage of hazardous chemicals. It is a holistic philosophy that is applied across the entire lifecycle of chemical products, including its design, manufacturing, usage, and ultimate disposal. The principles of green chemistry, also known as sustainable chemistry, can be applied to all areas of chemistry, not just a single discipline. Its goal is to apply innovative scientific solutions to real-world environment problems, resulting in source reduction by minimizing the generation of pollution (Jeon) as well as preventing pollution at the molecular level (EPA). By using green chemistry, we can reduce the negative impacts of chemical products and processes on human health and the environment. Furthermore, its use eliminates hazards from existing products and processes to reduce their intrinsic dangers. Some examples of green chemistry applications include biodegradable plastic, solar panels, wind turbines and electric cars.
Figure 1: the 12 principles of green chemistry by Let’s Talk. Science
Types of Cars
Over previous decades, petrol and diesel were the main fuels available to power vehicles. A petrol car uses a spark-ignited internal combustion engine, while the compression-ignited systems are installed in diesel vehicles. In the spark-ignited system, the fuel is injected into the combustion chamber and combined with air.
In the modern day, electric vehicles (EVs) have gained popularity worldwide due to their ecofriendly and sustainable nature. Unlike conventional vehicles that rely on gasoline or disel, they instead use electric power to run. They are powered by one or more electric motors, which convert electrical energy into mechanical energy to propel the vehicle. Depending on the types of vehicles, motion may be provided by wheels or propellers which are driven by rotary motors, or in the case of tracked vehicles, by linear motors.
Figure 2: Components of a Hydrogen Fuel Cell Electric Car by U.S. Department of Energy.
In addition, there is a car known as a hybrid vehicle, which uses both petrol and electricity to run. Since the late 1990s, these vehicles have utilized a combination of traditional fuel-based power and electricity. Hybrid electric vehicles are powered by an internal combustion engine and an electric motor, which uses energy stored in batteries. Unlike fully electric vehicles, hybrids cannot be plugged in to charge the battery; instead, the battery is charged through regenerative braking and by the internal combustion engine. The extra power provided by the electric motor can potentially allow for a smaller engine. The battery can also power auxiliary loads and reduce engine idling when stopped. Some of the components of a hybrid car include: auxiliary battery, DC/AC converter, electric generator, electric traction motor, exhaust system, fuel filler, fuel tank, internal combustion engine (spark-ignited), power electronics controller, thermal system, traction battery pack, and transmission (all star).
It is worth noting that each of the three types of cars - traditional petrol, electric, and hybrid - has its own set of advantages and disadvantages based on their design and system.
Figure 3: Components of a Plug-in Hybrid Electric Car by U.S. Department of Energy.
The Chemistry Behind the Main Component of Electric Vehicles: Lithium-ion Battery
Even though there are several manufacturing components that differentiate between an electric car and a conventional internal combustion engine car, the main distinction is the lithium-ion battery (Hyundai Motor Group).
As seen from the periodic table above, lithium has three electrons (the atomic number is the num-ber of electrons in the element), with two electrons in the inner shell and the one remaining in the outer shell, which is also known as the valence electron. This results in lithium being a highly reactive metal and is stable when it is part of a metal oxide (Goonan 1).
Due to its unique properties as the lightest metal and least dense solid element, lithium has emerged as a promising component for high energy-density rechargeable lithium-ion batteries. One of the key advantages of lithium is its high electrochemical potential, which refers to its high tendency to lose electrons. As an element with only one valence electron, lithium has an even higher tendency to lose electrons, making it an ideal choice for battery applications.
When an element loses or gains electrons, the element becomes an ion; therefore, if lithium gains or loses an electron, it becomes either a positively charged (loses electron) or negatively-charged (gains electron) lithium ion.
Lithium-ion battery was first commercialized in 1991, which instantaneously superseded nickel cadmium (NiCd) and nickel-metal hydride (Ni-MH) technologies who were previously the leading manufacturing batteries for cars (Renault Group).
The components of the lithium-ion battery cell include as follows:
Electrodes - the two battery ends; one is anode and the other is cathode.
Anode - stores lithium and typically made from carbon
Cathode - stores lithium and typically made from chemical compound that is a metal oxide
Separator - blocks flow of electrons inside the battery but allows ions to flow through
Electrolyte - sits between the two electrodes; carries positively charged lithium ions from the anode to the cathode and vice versa depending on whether the battery is charging or discharging.
In order to address the contentious issue of whether lithium-ion batteries are sustainable for the environment, it is necessary to conduct a comprehensive analysis of its roots
As the demand for electric vehicles is drastically increasing, so is the demand for lithium-ion batteries, which has led to a significant increase in the demand for raw materials such as lithium. To meet this demand, mining companies have utilized many strategies, with the two most common ones being the extraction of lithium from brines and the extraction from spodumene.
As displayed above, mining lithium from brines is very time-consuming, as it is dependent on the evaporation speed, which could take up to two years. Therefore, a new strategy has been deployed: hard-rock mining. Warran (3) stated that “the most valuable hardrock mines are dominated by granite pegmatites that contain the lithium-bearing mineral spodumene with a theoretical Li2O content of 8 wt. %”. The production process of lithium is shown in the figure below:
It is apparent that extracting lithium through the process of hard-rock mining requires less steps and could produce enough lithium to meet the increasing demand of lithium-ion batteries. Noticeably, both methods have negative impacts on the environment and ecosystem. For the first method, extraction from brines, soil must be dug up to 10 meters underground, affecting the soil quality, as well as the acres of land clearance for the construction of evaporation pools. The second method, extraction from hard-rock mining, requires the mining of granite pegmatites and the process of flotation to be carried out, which includes roasting rocks up to 1050 degrees Celsius; this will inevitably release harmful gases, e.g. carbon dioxide, to the environment.
How Electric Cars Improve the Economy
As the world moves towards a digital age, more advanced technologies are being developed, which contributes to significant economic development. The emergence of new technologies, including smart devices and electric vehicles, has made them widely available across the world. In particular, electric cars have gained popularity in recent years, leading to the expansion of the automotive industry, especially the electric vehicle (EV) market. The core component of electric cars is the battery, which is commonly made from lithium. This natural element is being used because of its ability to reduce the use of fossil fuels and memory effects (Sutopo et al). As a result, this specific natural element is being extracted to produce lithium-ion batteries. Countries such as Chile, Australia, China, and Argentina are the world’s largest producers of lithium (further datas are shown in the table below).
Figure 4:Lithium production in 2020 by Statista.
Despite the significant lithium production in certain countries like Chile, Australia, China, and Argentina, many countries still lack access to and the ability to produce their own lithium. This results in China, South Korea, and the United States being the largest lithium importers in the world (ClearPath). With the growing number of electric cars in the market, the demand for lithium extraction and mining is increasing, leading to more job opportunities for citizens (Doris Schüler et al). Thus, it increases the employment rate in the country, which can help them to maximize their family economy (Doris Schüler et al). In addition, country economic growth can be achieved due to the increase in domestic products in the country. An increase in gross domestic product (GDP) could lead to an improvement in essential political and social issues, such as poverty (The Guardian).
Conclusion
As presented in this report, electric vehicles do have some environmental impact, but they remain a superior option for reducing carbon emissions compared to standard petrol or diesel engines. The future of electric vehicles heavily relies on their battery If researchers can develop a "super battery", the future of electric vehicles looks promising. Despite some current limitations, the advantages of electric vehicles outweigh those of conventional cars, and we can use technology to find solutions to any drawbacks.
As we move forward into the future, environmentally friendly cars with the convenience of combustion engines will become increasingly widespread. It's likely that in the next few years, electric vehicles will become more widespread and unavoidable. This begs the question: will Cambodia adapt to this change?
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