As per NASA’s records, way back “In 1824, Joseph Fourier calculated that an Earth-sized planet, at our distance from the Sun, ought to be much colder. He suggested something in the atmosphere must be acting like an insulating blanket. In 1856, Eunice Foote discovered that blanket, showing that carbon dioxide and water vapour in Earth’s atmosphere trap escaping infrared (heat) radiation.”
Again, “In the 1860s, physicist John Tyndall recognized Earth’s natural greenhouse effect and suggested that slight changes in the atmospheric composition could bring about climatic variations. In 1896, a seminal paper by Swedish scientist Svante Arrhenius first predicted that changes in atmospheric carbon dioxide levels could substantially alter the surface temperature through the greenhouse effect.”
Later, “In 1938, Guy Callendar connected carbon dioxide increases in Earth’s atmosphere to global warming. In 1941, Milutin Milankovic linked ice ages to Earth’s orbital characteristics. Gilbert Plass formulated the Carbon Dioxide Theory of Climate Change in 1956.”
So, scientists realised the deterioration of the global climate years back, and called for preventive actions. However, the entire world, for political and economic interests, did not attach much importance to this warning of
the scientists.
Pollution caused by the IC engine driven vehicles plays a major role in increasing greenhouse gases into the atmosphere. It causes depletion of the ozone layer, which increases the atmospheric temperature – leading to global warming. I need not describe further on the effects of global warming – as we all are experiencing that these days.
Thus, one of the major goals in today’s world is to phase out the gasoline-powered vehicles introducing Electric Vehicles (EVs) as soon as possible. Battery is the heart of any electric vehicle that accounts for 40% of the electric vehicle cost. Naturally, there is a huge effort going on around the world to develop better batteries that are cheaper, safer, lighter and possess more power density. So, along with their own scientific research, the participating institutions/organisations/companies are sometimes choosing the path of partnership in an effort to speed up the work. The development of high-quality batteries is also progressing very fast, today I will talk about a few recent global developments in this industry.
Image Courtesy: Stellantis
Collaboration for developing advanced batteries
With a view to pursuing next-generation battery cell technology; Stellantis, one of the world’s leading automakers aiming to provide clean, safe and affordable freedom of mobility to all; has recently joined France’s CEA, a major research organisation.
It’s a five-year collaboration that targets in-house design of next-generation battery cells for EVs. This joint research programme includes designing advanced technology cells with higher performance, a longer lifespan and a lower carbon footprint at competitive costs, which can lead to more affordable & sustainable battery electric vehicles in the future.
Revealing their objective, Ned Curic, Stellantis Chief Engineering and Technology Officer, said, “We know that battery technology is poised for change. While we don’t know exactly how it will change, we are committed to be at the forefront of this transformation. Internally, we are working around the clock placing multiple bets and exploring various technologies. At the same time, we are collaborating closely with tech startups, laboratories, universities, and the most prestigious research institutions in the world like CEA. We believe that this collaboration will accelerate the arrival of disruptive battery cell technology, supporting our mission to offer clean, safe and affordable mobility to our customers.”
Commenting on the partnership, Philippe Stohr, Head of CEA Energy division, said, “CEA is proud to support Stellantis with an ambitious multi-year R&D program on battery cells, which takes place in the frame of CEA/Stellantis global partnership. This exciting project makes the best use of more than 25 years of expertise in the field of Li-ion batteries at CEA to the benefit of one of the major automotive actors in the competitive race for electrical mobility. Our challenge is to speed up design and fabrication and to allow deep understanding of the most advanced cells technologies by sharing our expertise, skills and vision.”
The goal of the joint battery cell programme is to provide more affordable, next-generation EV batteries with best-in-class technologies to Stellantis and its joint venture gigafactories.
The battery cell design programme reinforces a 20-year dynamic collaboration with CEA. Other areas of joint research include disruptive chemistries and CO2 footprint research, battery modeling, fuel cell development, life cycle assessment and connectivity.
Enhancing environment-friendliness
It is already established that the lithium metal batteries are among the most promising candidates of the next generation of high-energy batteries. They can store at least twice as much energy per unit of volume compared to the lithium-ion batteries that are in widespread use today. This will mean, for example, that an electric car can travel twice as far on a single charge, or that a smartphone will not have to be recharged so often.
While a new electrolyte design for lithium metal batteries could significantly boost the range of EVs, researchers at ETH Zurich have radically reduced the amount of environmentally harmful fluorine required to stabilise these batteries.
Working principle of a lithium metal battery
A battery consists of a negatively charged anode and a positively charged cathode. In a lithium-ion battery, the anode is made of graphite; in a lithium metal battery, it is made of lithium metal. Liquid electrolyte separates the anode and cathode. As the battery charges, positively charged lithium ions migrate from the cathode to the anode. When the lithium ions reach the anode, they lose their positive charge and form metallic lithium.
The shortcoming
As per the ETH Zurich scientists, at present, there is still one crucial drawback with lithium metal batteries: the liquid electrolyte requires the addition of significant amounts of fluorinated solvents and fluorinated salts, which increases its environmental footprint. Without the addition of fluorine, however, lithium metal batteries would be unstable, they would stop working after very few charging cycles and be prone to short circuits as well as overheating and igniting.
Graphic: Nobelprize.org
A research group led by Maria Lukatskaya, Professor of Electrochemical Energy Systems at ETH Zurich, has now developed a new method that dramatically reduces the amount of fluorine required in lithium metal batteries, thereby rendering them more environmentally friendly and more stable as well as cost-effective.
The fluorinated compounds from electrolyte help the formation of a protective layer around the metallic lithium at the negative electrode of the battery. As explained by Lukatskaya, “This protective layer can be compared to the enamel of a tooth. It protects the metallic lithium from continuous reaction with electrolyte components.” Without it, the electrolyte would quickly get depleted during cycling, the cell would fail, and the lack of a stable layer would result in the formation of lithium metal whiskers – ‘dendrites’ – during the recharging process instead of a conformal flat layer.
Should these dendrites touch the positive electrode, this would cause a short circuit with the risk that the battery heats up so much that it ignites. The ability to control the properties of this protective layer is therefore crucial for battery performance. A stable protective layer increases battery efficiency, safety and service life.
Focusing on the research, Doctoral student Nathan Hong, said, “The question was how to reduce the amount of added fluorine without compromising the protective layer’s stability. The group’s new method uses electrostatic attraction to achieve the desired reaction. Here, electrically charged fluorinated molecules serve as a vehicle to transport the fluorine to the protective layer. This means that only 0.1% by weight of fluorine is required in the liquid electrolyte, which is at least 20 times lower than in prior studies.
Epilogue
Although in the small span of this article, I have highlighted only two recent developments in the battery industry, worldwide lot of other activities are going on to develop high-quality batteries. In the next few years, definitely this industry will procure batteries that will enable the EVs to be more efficient than today’s most efficient IC engine driven vehicles.
By P. K. Chatterjee (PK)
