Lithium: Powering the Green Revolution

by Richard A Lovett

As the climate warms, sea levels rise and droughts, heatwaves and bushfires multiply, the need to usher in the green-energy future is increasingly urgent. But that doesn’t mean it can be done without significant challenges – not just in the economy (as it makes the changeover), but technologically and scientifically as well.

It’s a problem reminiscent of the 1970s environmental rallying cry TANSTAAFL (There ain’t no such thing as a free lunch), drawn from a 1966 novel by science fiction writer Robert A. Heinlein. All things come at a price, the idea goes, and while the price of excessive reliance on fossil fuels is increasingly evident, that doesn’t mean there aren’t going to be issues with weaning ourselves off them. 

One of these “issues” is lithium.

Most of us have never seen pure lithium, and never will. In this form, it is a soft silvery-white metal that so easily corrodes it has to be kept in mineral oil to protect it from air. But we all use it: it’s the magic ingredient in the lithium-ion batteries that power everything from our smartphones and watches to electric vehicles.

Prior generations of rechargeable batteries used lead and acid, nickel-cadmium mixes, and nickel mixed with other materials. Lithium, however, is a lot less toxic, holds its charge better when not in use, and is less susceptible to developing the “battery memory” problem in which ageing batteries fail to fully recharge. But its biggest advantage is that it is a lot lighter. Lithium is element number three on the periodic table: eight times lighter than nickel, 16 times lighter than cadmium, 30 times lighter than lead. 

In other words, when it comes to batteries, it packs a lot more bang for the buck (or, more precisely, the gram). “For a given weight, it will have the maximum amount of power,” says Edward Goo, director of the materials science program at the University of Southern California’s Viterbi School of Engineering. 

Michael Whittaker, director of the newly formed Lithium Resource Research and Innovation Center (which sports the musical-sounding acronym of LiRRIC) at America’s Lawrence Berkeley National Laboratory, adds that lithium is so light that it makes up only 1–2% of a lithium-ion battery’s total mass. If you’re going to haul it around in a wristwatch, laptop computer, electric vehicle, or even an airplane, he says, it really is vastly better. “For lightweight applications, lithium batteries will likely remain an integral part of the battery market for a long time to come,” he says. 

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In a rechargeable battery, lithium ions move across the electrolyte to the positive electrode (cathode), producing the energy that powers the electrode. As it recharges, the cathode gives up some of its lithium ions, which move to the negative electrode (anode). The electrons follow the same path in the outer circuit. Credit: Ser_Igor / Getty Images

There’s just one fly in the ointment. There are concerns about how we can get enough of it to power the alternative-energy future. Demand is expected to double in the next five years – and increase tenfold by 2030. And that has everyone scrambling to find new sources of it, lest lithium shortages grind the green economy to an unhappy halt.

One of the biggest drivers of that expanding demand is going to be electric vehicles. A Tesla Model S needs 64 kilograms of lithium – roughly 10,000 times the amount in the typical mobile phone. With current global production at 77,000 tonnes, according to the US Geological Survey (USGS; 2019 data), that means the world is only producing enough lithium to power 1.2 million new electric cars per year – at a time when total automobile production is more like 92 million. If the phrase “drop in the bucket” comes to mind, you might not be all that far off.

But that’s not the only way in which the green-energy future will call for vast increases in lithium production, says Whittaker’s colleague Peter Fiske. 

Climate change already appears to be fanning the flames of fires in large parts of the world, from California to Australia, and power companies are realising that they need to cut service in dry, windy conditions, lest sparks from downed powerlines produce catastrophic conflagrations. “All of us had the power to our houses shut off at least once this summer,” Fiske says of himself and his colleagues. “We are now imagining that shutting off the power grid is going to be a fact of life.” 

To weather such shutdowns, people in fire-prone areas are going to want something to tide them through, and batteries are an obvious answer. Already, Tesla is marketing Powerwalls that can do this, as well as store solar energy from sunny days and parcel it out when the clouds hang low. “This will further add to the demand for lithium,” Fiske says.

Industrial production of lithium comes from two sources. One is traditional mining of rocks containing lithium ores, particularly a mineral called spodumene: a mix of lithium, aluminium, silicon and oxygen (LiAlSi2O6) that can form crystals so big the US Geological Survey (USGS) has described them as “logs”. The biggest known have attained lengths of 13 metres and widths of 160 centimetres. “You can buy them on eBay,” (though not quite at that size) Lee told Cosmos

“Spodumene contains [as much as] 3.7% lithium by mass, and is one of the highest-grade lithium ores known,” Whitaker says. “There are a number of spodumene processing operations, mainly in Australia.” In fact, thanks to these, Australia has become the world’s largest producer of lithium, accounting for about 54% of the world’s production, according to USGS statistics. 

But it doesn’t have the world’s largest reserves. Those, USGS reports, lie in Chile and Argentina, where lithium-rich water is pumped from beneath the surface of dry lakebeds called salars and allowed to evaporate in the harsh sunlight of the starkest deserts in the world. Those two countries, plus Bolivia, whose similar lithium brines are currently untapped, form what Lee calls the “lithium triangle” and contain at least 60% of the world’s known reserves as of 2019 (the latest year for which figures are available). 

These reserves are large enough that we aren’t going to run out soon – though if demand continues to grow exponentially, they might become seriously stretched by the late 2030s. In fact, Lee argues, “we will never run out of any material because of scarcity. It’s always going to be economic, environmental and social concerns.”

Richard A Lovett is a US-based science writer and science-fiction author. This is an excerpt from his feature article in the latest edition of Cosmos magazine. You can subscribe to Cosmos here.

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