Companies look for greener EV battery graphite supplies | World News

Despite the economic downturn and Component shortageMore than 13 million plug-in electric or hybrid passenger vehicles are likely to be sold this year, according to BloombergNEF.this will take Number of Electric Vehicles From 27m to over 40m on world roads. But that’s still only about 3% of the total number of vehicles on Earth. With 97% still to be needed, the mass electrification of transportation means a huge demand for batteries and the materials they are made from.

Automakers are already fretting over spiraling prices and limited supplies of lithium, a key ingredient in the lithium-ion batteries at the heart of the revolution.They also worry about cobalt and other components used to make cathodes, the positive electrodes inside batteries (although new reserves recently discovered have dispel those worries because they are especially associated with cobalt). It does take two people to dance tango, though. For each cathode, the battery needs an anode, a negative electrode. Anodes are made of graphite, and a supply shock for this material is in the offing.

Graphite is a form of carbon in which atoms are arranged in sheets. Among other things, it is the material used as the “lead” of a pencil – not quite the highest level of technical application. As such, anodes are considered somewhat dull compared to cathodes, and the raw materials to make them are in plentiful supply. But demand for graphite will rise from 1.2 million tonnes in 2022 to more than 4 million tonnes a year in 2030, driven by rising sales of electric vehicles, according to London-based analyst firm Benchmark Mineral Intelligence. Currently, supply is growing at only about two-thirds of that rate. So there may not be enough graphite to be recycled, especially since there are other big users of the material, such as the steel industry.

Graphite used in batteries comes in two forms, each with advantages and disadvantages. One is natural, dug from the ground – although the mines that produce the best grades are few and far between. The other is synthetic and comes from the roasting of so-called needle coke, a byproduct of some coal processing and petrochemical plants. This roasting is an energy-intensive process that results in significant emissions. Currently, most of the graphite used in anodes is made this way, but as more automakers worry about their green credentials, they will increasingly, says Benchmark’s Andrew Miller. Look around for cleaner mineral varieties.

Deep excavation

Regardless of its origin, graphite must be purified to a level of 99.95 percent or better—because the slightest impurity can interfere with the inflow and outflow of lithium ions. These ions are created at the cathode by stripping electrons from lithium atoms when the battery is charged. Electrons are sent to the anode through an external circuit, and ions are also sent to the anode through the electrolyte inside the battery. When they reach the anode, these ions combine with electrons provided by an external circuit to reform lithium atoms. They are then dispersed in the atomic layers of graphite until battery power is required. The process is then reversed, but with the electrons in the external circuit powering the device, such as the EV’s electric motor.

Graphite remains by far the best anode material. But purifying it is a hassle. Traditionally, highly corrosive chemicals such as hydrofluoric acid are used to dissolve impurities. Most of the processing is done in China. Automakers have been very nervous about China controlling about 60% of the world’s lithium resources. However, when it comes to graphite, China controls more than 90% of the supply chain.

All of this has led many companies to look to diversify their supply by opening graphite mines and processing plants elsewhere, especially in the US and Europe. As these operations are often performed in places that impose strict environmental constraints on industry, cleaner methods are needed. While companies are wary of divulging trade secrets, the methods they are devising should help clean up the industry.

black gold

One of Europe’s first battery anode factories in Luleå in northern Sweden has started delivering production samples to carmakers. Owned by Perth, Australia’s Talga, the plant is supplied by the company’s graphite mine near Vittangi, 300km further north. The Vittangi mine produces some of the highest grade graphite in the world, which means less waste is produced. Talga boss Mark Thompson said the environmental impact could thus be kept to a minimum.

The Luleå plant uses a process called low-temperature alkali roasting to release impurities from the graphite crystal structure. They are then washed away with an acid milder than hydrofluoric acid. Mr Thompson said this produced less waste than traditional methods. To earn green credits, the plant is powered by renewable hydroelectricity widely available in Sweden. The company points to an independent analysis that found the combination produced 96% fewer greenhouse gas emissions than making synthetic graphite. Still, Talga is working on a proprietary process to make production more environmentally friendly.

As is customary in the industry, graphite, once purified, is reduced to tiny spheres to form a fine black powder before being shipped to battery manufacturers. Their shape allows these particles to pack efficiently into the anode, increasing the contact between them and thus increasing the overall conductivity. The anode fabrication itself is done by turning the graphite into a slurry which is then coated onto strips of copper film.

Talga expects its Swedish factory to produce more than 100,000 tonnes of anode graphite per year. Depending on the size and performance characteristics of an EV, its battery pack may contain around 70-90 kg of graphite. As a result, the company’s annual production capacity can power more than 1 million new vehicles.

On the other side of the world, Anthony Huston, founder of Vancouver, Canada-based company Graphite One, is trying something similar. His company is conducting exploratory mining at the aptly named Graphite Creek near Nome in western Alaska (a sample is shown in the picture on the previous page). Estimated to contain more than 8 million tons of graphite, it is the largest deposit in the United States—the country has imported all of its graphite since the 1950s.

The idea is to ship the graphite south to a processing plant, which will be built at an as-yet-undetermined site in Washington state, Mr. Houston said. Here, it is purified and processed, also using renewable energy. Graphite One is working with Sunrise New Energy, a Chinese anode materials company based in Zibo, Shandong Province, to develop a purification system that gently heats graphite in the presence of a recyclable cleaning gas.

Nico Cuevas, owner of a company called Urbix, is working on a completely different approach to graphite processing. Urbix built a demonstration plant at its site in Mesa, Arizona. This is understood to be the use of heat and mechanical means to excite the graphite flakes so that the carbon layers inside open up, allowing impurities to be washed away by less harmful chemicals.

Mr Cuevas said the Urbix method was a low-energy process that was clean enough to operate on sites zoned for light industrial use. The company will use graphite from potential sources in North America and has signed a joint development agreement with South Korean battery giant SK On. SK On already has two battery gigafactories in the US and has formed a joint venture with Ford to build three more.

The researchers are developing anodes using other materials. In theory, silicon and lithium metal anodes are more efficient at storing energy, but both have problems. Silicon, in particular, expands and contracts as it is charged and discharged, which can damage the battery. However, small doses of this material can be mixed into graphite to improve its properties. Urbix says its process allows such substances to be incorporated into the core of its graphite spheres.

Another possibility is to use a different type of carbon. Finnish forest products company Stora Enso thinks it can make anode material from lignin. It’s a natural polymer that gives wood its stiffness, but it’s considered a waste product when wood is processed into paper. Normally, it burns to generate heat. Stora Enso plans to refine it into toner.

Stora Enso would not elaborate on how they do this, other than to say that their process involves multiple thermal and mechanical treatments at lower temperatures than those traditionally used to produce synthetic graphite. Swedish battery maker Northvolt is considering using the company’s material.

There is no doubt that alternatives to graphite will continue to improve. But with huge investments in gigafactories—nearly $300 billion over the past four years, according to Benchmark, much of it based on familiarity with existing materials—graphite looks set to hold up for some time to come. own status. With new, low-impact mines and cleaner processes, the dark side of electric vehicles could soon become greener.

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© 2023, The Economist Limited. all rights reserved. From The Economist, published with permission.Original content available at www.economist.com