Is lithium-ion the ideal battery for electric vehicles?
Lithium Ion Batteries – The backbone of the Electric Vehicle Revolution in Asia
Science / Auto, Aviation & Transportation
Nearly 92% of Asia’s population – approximately 4 billion people – are exposed to levels of air pollution which pose significant health risks. Densely populated cities like New Delhi, Beijing, and Jakarta experience the brunt of this environmental issue with air pollution levels up to 10 times that of World Health Organization guidelines. To alleviate this problem, many cities are encouraging the use of cleaner, zero emission electric vehicles (EVs) powered by renewable energy, in the hopes that such technology will soon supplant the almost 40 million gas powered automobiles purchased annually across Asia. And while such vehicles still have a long way to go, they have, indeed, found success. In 2018, approximately 1.1 million electric vehicles sold in China alone, which accounted for more than 55% of global sales.
The single most important element of the electric vehicle is the battery.
Though the invention of the electric vehicle dates back to the early 1800s, the technology was not commercialized for another two centuries due to the low energy density of the batteries that would power them, instead, they were abandoned in favor of gasoline powered automobiles developed by Karl Benz and subsequently Henry Ford. It was only after the development of the Lithium-Ion Battery chemistry in the 1970s – an innovation that offered an energy density of more than six times that of their predecessors, the Lead Acid battery – that electric vehicle production returned into the realm of possibility.
Lithium ion batteries release energy by the oxidation of lithium metal into lithium ions. Which, having lost 1 of their electrons, are then shuttled to the cathode – the negative electrode material – of the battery. During charging, the process becomes reversed. Lithium ions which accumulated in the cathode of the battery become reduced and transported back to the anode, where they precipitate into their pure metallic phase. Lithium is the lightest of all metals on the periodic table and also delivers a high voltage of 3.7 Volts (lead acid delivers 1.2 volts) when oxidized and coupled with a suitable cathode, which allow such batteries to truly pack in a punch.
A vast majority of commercialized lithium ion batteries utilize a cathode derived from the metal cobalt. The cathode is normally the limiting factor of the batteries performance and energy density; cobalt based cathodes have, however, have enabled such batteries to store some of the highest energy densities witnessed. Most Lithium Ion cells deliver up to 250 Watt hours of energy per kilogram of battery. Which is a far cry from the 40-50 Watt hours of energy delivered per kilogram of the Lead Acid batteries.
Is lithium-ion the ideal battery for electric vehicles?
Moreover, during the charging process of the battery the lithium ions that were coordinated to the metal particles in the cathode are rapidly removed. Unlike other potential contenders for the cathode, such as Manganese, Vanadium, Molybdenum, Iron, and Nickel based materials. Cobalt in its Oxide form, Cobalt (IV) Oxide, has a crystal structure which remains virtually immobile as the lithium ions become inserted and removed. This enables ultra-durability. Whereby the battery can become charged and discharged hundreds, sometimes thousands, of times. Before it must become replaced.
Though these Lithium Ion batteries can indisputably be dubbed the “king” of energy storage technologies, their overreliance on cobalt may very well be their biggest pitfall.
Cobalt is an expensive metal, costing anywhere between $41,000 to $86,000 per tonne. Moreover, 70% of the world’s cobalt supply originates from the Democratic Republic of Congo. An impoverished African nation well endowed in natural resources. The majority of the nation’s cobalt mines are artisanal and small scale, being controlled by warlords. This renders global cobalt supply to be highly unstable and leads to extreme price volatility. With global cobalt prices subject to changes on the order of 30+% per month.
To meet global cobalt demand, Congo mines often resort to utilizing child labor, with an estimated 40,000 child laborers working to extract cobalt. These mines are one of the many reasons as to why literacy rates and development indicators of the country remain as some of the lowest worldwide. Meanwhile, the abysmal working conditions and lack of protective equipment in such mines has forced workers to mine bare handed and without masks. The dust in mines and the toxicity of cobalt, alongside other elements encountered, has caused systemic poisoning and respiratory tract problems to the miners.
Figure 2: Child Laborers mining cobalt in the Congo [2]
Fortunately, alternatives to cobalt do exist and are slowly becoming commercialized. Many automakers now switch their battery cathodes to become composed of a nickel, manganese and cobalt (NCM) concoction. In an attempt to reduce their reliance on the precarious and more costly cobalt. Initially NCM cathodes became developed such that the metals existed in a 1:1:1 ratio. However, as time progressed, the percentage of cobalt utilized reduced. Last year, LG Chem, the chemical/materials innovation wing of the Korean conglomerate, announced that it would be introducing a groundbreaking 8:1:1 ratio of the three metals in its vehicles.
Other cathode materials such as the Lithium Manganese Oxide cathodes used in the Nissan Leaf or the Lithium Iron Phosphate cathodes utilized by chinese electric bus manufacturer BYD are also potential candidates, especially due to the substantially lower cost of Iron and Manganese. Nevertheless, their durability and energy density cannot compare to batteries whose cathodes are cobalt based.
By offering subsidies, phasing out gasoline vehicles. Moreover, encouraging the private sector to switch to electric vehicle production. As a result, leaders of Asian countries make a bold stand. In the hope of alleviating air pollution and climate change. With a switch to cobalt free cathodes. Which could result from further investment into the R&D for lithium-ion batteries. Lastly, a more sustainable future could become a possibility for cities in Asia.
Is lithium-ion the ideal battery for electric vehicles?
Written by Vasu Kaker
Science
Bibliography (for images):
[1] GovandBusinessJournal. (2019, February 28). Electric vehicles in China: New insights. [2] FreightWaves. Hampstead, J. P., & Mith, J. (2019, March 25). The trouble with cobalt.
Is lithium-ion the ideal battery for electric vehicles?
