The age of the electric car is upon us. Earlier this year, the US automobile giant General Motors announced that it aims to stop selling petrol-powered and diesel models by 2035. Audi, based in Germany, plans to stop producing such vehicles by 2033. Many other automotive multinationals have issued similar road maps. Suddenly, major carmakers’ foot-dragging on electrifying their fleets is turning into a rush for the exit.
The electrification of personal mobility is picking up speed in a way that even its most ardent proponents might not have dreamt of just a few years ago. In many countries, government mandates will accelerate change. But even without new policies or regulations, half of global passenger-vehicle sales in 2035 will be electric, according to the BloombergNEF (BNEF) consultancy in London.
This massive industrial conversion marks a “shift from a fuel-intensive to a material-intensive energy system”, declared the International Energy Agency (IEA) in May1. In the coming decades, hundreds of millions of vehicles will hit the roads, carrying massive batteries inside them (see ‘Going electric’). And each of those batteries will contain tens of kilograms of materials that have yet to be mined.The age of the electric car is upon us. Earlier this year, the US automobile giant General Motors announced that it aims to stop selling petrol-powered and diesel models by 2035. Audi, based in Germany, plans to stop producing such vehicles by 2033. Many other automotive multinationals have issued similar road maps. Suddenly, major carmakers’ foot-dragging on electrifying their fleets is turning into a rush for the exit.
The electrification of personal mobility is picking up speed in a way that even its most ardent proponents might not have dreamt of just a few years ago. In many countries, government mandates will accelerate change. But even without new policies or regulations, half of global passenger-vehicle sales in 2035 will be electric, according to the BloombergNEF (BNEF) consultancy in London.
This massive industrial conversion marks a “shift from a fuel-intensive to a material-intensive energy system”, declared the International Energy Agency (IEA) in May1. In the coming decades, hundreds of millions of vehicles will hit the roads, carrying massive batteries inside them (see ‘Going electric’). And each of those batteries will contain tens of kilograms of materials that have yet to be mined.
Anticipating a world dominated by electric vehicles, materials scientists are working on two big challenges. One is how to cut down on the metals in batteries that are scarce, expensive, or problematic because their mining carries harsh environmental and social costs. Another is to improve battery recycling, so that the valuable metals in spent car batteries can be efficiently reused. “Recycling will play a key role in the mix,” says Kwasi Ampofo, a mining engineer who is the lead analyst on metals and mining at BNEF.
Battery- and carmakers are already spending billions of dollars on reducing the costs of manufacturing and recycling electric-vehicle (EV) batteries - spurred in part by government incentives and the expectation of forthcoming regulations. National research funders have also founded centres to study better ways to make and recycle batteries. Because it is still less expensive, in most instances, to mine metals than to recycle them, a key goal is to develop processes to recover valuable metals cheaply enough to compete with freshly mined ones. “The biggest talker is money,” says Jeffrey Spangenberger, a chemical engineer at Argonne National Laboratory in Lemont, Illinois, who manages a US federally funded lithium-ion battery-recycling initiative, called ReCell.
Lithium future:-
The first challenge for researchers is to reduce the amounts of metals that need to be mined for EV batteries. Amounts vary depending on the battery type and model of vehicle, but a single car lithium-ion battery pack (of a type known as NMC532) could contain around 8 kg of lithium, 35 kg of nickel, 20 kg of manganese and 14 kg of cobalt, according to figures from Argonne National Laboratory.
Analysts don’t anticipate a move away from lithium-ion batteries any time soon: their cost has plummeted so dramatically that they are likely to be the dominant technology for the foreseeable future. They are now 30 times cheaper than when they first entered the market as small, portable batteries in the early 1990s, even as their performance has improved. BNEF projects that the cost of a lithium-ion EV battery pack will fall below US$100 per kilowatt-hour by 2023, or roughly 20% lower than today (see ‘Plummeting costs of batteries’). As a result, electric cars - which are still more expensive than conventional ones - should reach price parity by the mid-2020s. (By some estimates, electric cars are already cheaper than petrol vehicles over their lifetimes, thanks to being less expensive to power and maintain.)
To produce electricity, lithium-ion batteries shuttle lithium ions internally from one layer, called the anode, to another, the cathode. The two are separated by yet another layer, the electrolyte. Cathodes are the main limiting factor in battery performance - and they are where the most valuable metals lie.
The cathode of a typical lithium-ion battery cell is a thin layer of goo containing micro-scale crystals, which are often similar in structure to minerals that occur naturally in Earth's crust or mantle, such as olivines or spinels. The crystals pair up negatively charged oxygen with positively charged lithium and various other metals - in most electric cars, a mix of nickel, manganese and cobalt. Recharging a battery rips lithium ions out of these oxide crystals and pulls the ions to a graphite-based anode where they are stored, sandwiched between layers of carbon atoms (see 'Electric heart).
Lithium itself is not scarce. A June report by BNEF2 estimated that the current reserves of the metal - 21 million tonnes, according to the US Geological Survey - are enough to carry the conversion to EVs through to the mid-century. And reserves are a malleable concept, because they represent the amount of a resource that can be economically extracted at current prices and given current technology and regulatory requirements. For most materials, if demand goes up, reserves eventually do, too.
As cars electrify, the challenge lies in scaling up lithium production to meet demand, Ampofo says. “It’s going to grow by about seven times between 2020 and 2030.”
This could result in temporary shortages and dramatic price swings, he says. But market hiccups will not change the picture in the long term. “As more processing capacity is built, these shortages are likely to work themselves out,” says Haresh Kamath, a specialist in energy storage at the Electric Power Research Institute in Palo Alto, California.
The increase in lithium mining carries its own environmental concerns: current forms of extraction require copious amounts of energy (for lithium extracted from rock) or water (for extraction from brines). But more-modern techniques that extract lithium from geothermal water, using geothermal energy to drive the process, are considered more benign. And despite this environmental toll, mining lithium will help to displace destructive fossil-fuel extraction.
Researchers are more worried about cobalt, which is the most valuable ingredient of current EV batteries. Two-thirds of global supply are mined in the Democratic Republic of the Congo. Human-rights activists have raised concerns over conditions there, in particular over child labour and harm to workers’ health; like other heavy metals, cobalt is toxic if not handled properly. Alternative sources could be exploited, such as the metal-rich ‘nodules’ found on the sea floor, but they present their own environmental hazards. And nickel, another major component of EV batteries, could also face shortages.
Managing metals:-
To address the issues with raw materials, a number of laboratories have been experimenting with low-cobalt or cobalt-free cathodes. But cathode materials must be carefully designed so that their crystal structures don’t break up, even if more than half the lithium ions are removed during charging. And abandoning cobalt altogether often lowers a battery’s energy density, says materials scientist Arumugam Manthiram at the University of Texas in Austin, because it alters the cathode’s crystal structure and how tightly it can bind lithium.
Manthiram is among the researchers who have solved that problem - at least in the lab - by showing that cobalt can be eliminated from cathodes without compromising performance4. “The cobalt-free material we reported has the same crystal structure as lithium cobalt oxide, and therefore the same energy density,” or even better, says Manthiram. His team did this by fine-tuning the way in which cathodes are produced and adding small quantities of other metals - while retaining the cathode's cobalt-oxide crystal structure. Manthiram says it should be straightforward to adopt this process in existing factories, and has founded a start-up firm called TexPower to try to bring it to market within the next two years. Other labs around the world are working on cobalt-free batteries: in particular, the pioneering EV maker Tesla, based in Palo Alto, California, has said it plans to eliminate the metal from its batteries in the next few years.
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