by Ddespite likely With bumps in the road ahead caused by flagging economies and component shortages, more than 13 million plug-in fully electric or hybrid passenger cars are expected to be sold this year, according to BloombergNEF. This takes the number of EVs on the roads of the world from 27 m to over 40 m. But that is still only around 3% of the global vehicle fleet. With another 97% ahead of mass electrification of transportation, there will be huge demand for batteries and the materials from which they are made.
Automakers are already fret over soaring prices and limited supplies of lithium, the critical ingredient in lithium-ion batteries at the heart of this revolution. They’re also concerned about cobalt and other ingredients used to make cathodes, the positive electrodes in these batteries (although recent discoveries of new reserves have dampened those concerns, as they relate specifically to cobalt). However, it takes two to tango. For every cathode, a battery needs an anode, a negative electrode. Anodes are made from graphite and a supply shock is looming for this material.
Graphite is a form of carbon in which the atoms are arranged in layers. Among other things, it is the material used as a “lead” in pencils – hardly the highest technical application. Therefore, anodes have been considered somewhat dull compared to cathodes due to the plentiful supply of raw materials from which to make them. But driven by growth EV According to Benchmark Mineral Intelligence, a London-based analyst firm, graphite demand will triple from 1.2 million tonnes in 2022 to more than 4 million tonnes per year by 2030. Supply is currently growing at only about two-thirds of that rate. So there may not be enough graphite, especially since this material also has other big users, such as the steel industry.
Graphite, used in batteries, comes in two forms, each with advantages and disadvantages. One is natural, dug out of 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 by-product produced in some coal processing and petrochemical plants. This roasting is an energy-intensive process that results in high emissions. Currently, most graphite for anodes is made this way, but carmakers concerned about their environmental credentials will increasingly seek the cleaner, mineral variant, says Benchmark’s Andrew Miller.
deep ditch
Regardless of its origin, graphite must be purified to a degree of 99.95% or better – because the smallest impurity interferes with the inflow and outflow of lithium ions. When charging a battery, these ions are created at the cathode by drawing electrons from lithium atoms. The electrons are sent to the anode via an external circuit, and the ions are also directed in that direction via an electrolyte in the battery. When they reach the anode, these ions combine with the electrons supplied by the external circuit to form new lithium atoms. These are then displaced in the atomic layers of the graphite until the battery is called upon to supply energy. The process then reverses, but with the electrons in the external circuit powering a device such as a EVThe electric motor.
So far, graphite is the best available material for anodes. But cleaning it is a messy business. Traditionally, highly corrosive chemicals such as hydrofluoric acid are used to dissolve contaminants. Most of this processing takes place in China. Automakers were nervous enough because this country controls about 60% of the world’s lithium. But when it comes to graphite, China controls more than 90% of the supply chain.
All of these things have prompted a number of companies to diversify their supplies by opening graphite mines and processing plants elsewhere, particularly in America and Europe. Because these operations are often located in locations that place stringent environmental regulations on the industry, cleaner methods are required. Although companies are wary of disclosing trade secrets, the approaches they have devised should help clean up the industry.
Black gold
One of Europe’s first battery anode plants in Lulea, northern Sweden, has already started supplying car manufacturers with production samples. This plant, owned by Talga, a Perth, Australia company, is fed from a graphite mine that the company has developed near Vittangi, 300 km to the north. The Vittangi mine produces some of the highest quality graphite in the world, which means less waste material is generated. The environmental impact can therefore be kept low, says Mark Thompson, head of Talga.
The Lulea facility uses a process called low-temperature alkaline roasting to liberate impurities from the crystal structure of graphite. These are then washed away with milder acids than hydrofluoric acid. Mr. Thompson says it creates less waste than traditional approaches. For bonus green points, the factory is powered by Sweden’s extensive range of renewable hydroelectric power. The company points to an independent analysis that found the combination produces 96% fewer greenhouse gas emissions than producing synthetic graphite. Nevertheless, Talga is working on its own processes to make production even greener.
As is common in the industry, after purification, graphite is reduced to tiny globules that form a fine black powder before being shipped to battery manufacturers. Their shape allows these particles to be efficiently packed into an anode, increasing the contact between them and therefore the overall conductivity. The anode fabrication itself is done by converting the graphite into a slurry and then applying it to strips of copper film.
Talga hopes its Swedish operation will produce more than 100,000 tons of anode graphite per year. Depending on the size and performance characteristics EV, its battery pack might contain about 70-90 kg of graphite. The company’s annual output could therefore be used to power more than 1 million new vehicles.
On the other side of the world, Anthony Huston, founder of Graphite One, a company in Vancouver, Canada, is trying something similar. His company is engaged in exploration mining on the appropriately named Graphite Creek near Nome in western Alaska (samples of which are shown in the image on the previous page). It is estimated to contain more than 8 million tonnes of the material, the largest deposit in the United States – a country that has imported all of its graphite since the 1950s.
The idea, Mr. Huston says, is to ship the graphite south to a processing plant to be built at a yet-to-be-determined Washington state location. Here it would be cleaned and processed, also with renewable electricity. Graphite One is working with Sunrise New Energy, a Chinese anode materials company in Zibo, Shandong province, on a cleaning system that gently heats the graphite in the presence of recyclable cleaning gases.
Nico Cuevas, head of a company called Urbix, is looking for a completely different way to process graphite. Urbix has built a demonstration plant at its Mesa, Arizona site. This is the use of heat and mechanical means to excite graphite flakes so that the carbon layers within them open up and contaminants can be washed away with less harmful chemicals.
The Urbix process is an energy-efficient process that is clean enough to be carried out on a site designated for light industrial use, says Mr. Cuevas. The Company will use graphite from potential sources in North America and has signed a joint development agreement with SK On, a South Korean battery giant. SK On already has two battery gigafactories in America and has formed a joint venture with Ford to build three more.
Researchers are developing anodes that use other materials. Silicon and lithium metal anodes are theoretically more efficient at storing energy, but both come with problems. Silicon, in particular, swells and contracts during charging and discharging, which could damage a battery. However, small doses of such a material can be mixed into graphite to increase its performance. Urbix says its process allows such substances to be incorporated into the core of its graphite spheres.
Another option is to use a different type of carbon. Stora Enso, a Finnish forest products company, believes it can produce anode material from lignin. This is a natural polymer that gives wood its rigidity, but is treated as a waste product when wood is turned into paper. Usually it is burned to generate heat. Stora Enso plans to refine it into carbon powder.
Stora Enso will not elaborate on how they do this, other than saying that their process involves several heat and mechanical treatments that take place at lower temperatures than those traditionally used to produce synthetic graphite. Northvolt, a Swedish battery manufacturer, is considering using the company’s material.
Alternatives to graphite will no doubt continue to evolve. But with such huge investments pouring into gigafactories – nearly $300 billion over the past four years, according to Benchmark, and most of it based on a familiarity with the material at hand – it looks like graphite is still making some claim time. With new, gentle mines and cleaner processes, the dark side of the electric car should soon become a little greener. â–
