Australia gears up for graphite

In the sixth and final instalment of the Australian Mining Review’s critical minerals series, we dive deep into the global outlook for graphite and emerging mid-stream processing pathways as highlighted in the CSIRO’s From Minerals to Materials: An Assessment of Australia’s Critical Minerals Mid-Stream Processing Capabilities report and the IEA’s Global Critical Minerals Outlook 2024.

While lithium dominates the discussion around next-gen batteries, a key material, graphite, is often overshadowed. According to the IEA, in a 2050 net zero scenario, graphite demand increases by four times by 2040, with the market undergoing almost sixfold growth over the period, propelled by the substantial increase in battery deployment for EVs and grid storage.

Although Australia has no commercial scale production of graphite materials, several companies have conducted tests and pilots and plan to vertically integrate from their natural graphite deposits.

While current graphite supply is abundant, it pales in the face of this future demand. But how do we get there? According to the IEA, concerted efforts to expedite the development of promising projects located in geographically diverse regions as well as harnessing the potential for value chain expansion in major resource holders in emerging and developing economies are key.

The geopolitics at play make the situation even trickier for graphite, especially when it comes to new entries into the market.

Natural graphite mining is dominated by China, which accounts for 80% of global production according to the IEA. However, because of the sensitive nature of battery materials, not all forms of natural graphite can be used in the supply chain. This may seem like it opens a gap in the market, but most battery producers globally are heavily reliant on China for graphite anodes, according to the IEA. The sizeable natural graphite anode capacities that exist outside of China, still depend on the country’s refined graphite supply. The true entry point now is found in this mid-stream processing of refined graphite.

Some Australian firms made waves in the global graphite industry recently, joining ranks with American graphite companies in a petition urging the U.S. Department of Commerce and International Trade Commission to investigate China’s alleged dumping of graphite products at unsustainable and unfair prices.

ASX-listed Syrah Resources (ASX: SYR) and Novonix (ASX: NVX) are both participating in the petition. According to Novonix, the filing asserts China is harming the nascent domestic graphite industry by exporting artificially cheap battery-grade graphite into the United States, denying North American producers a fair opportunity to enter the market.

According to Syrah, graphite is the most significant mineral by mass in lithium-ion batteries (LiBs). The supply of graphite AAM, and its feedstocks and precursor materials, are highly concentrated in China with the country currently holding over 95% market share for battery grade graphite, according to Novonix.

“It is apparent that China is employing an overcapacity strategy in synthetic graphite AAM resulting in suppliers from China selling graphite AAM into the United States battery market at unfair prices in some cases underpinned by support from the Chinese Government,” Syrah said in a statement.

“These actions are creating significant challenges for ex-China natural graphite and AAM companies and denying such companies a fair opportunity to compete for graphite AAM sales and invest in further expansion of AAM production capacity in the United States.”

Experts at Buchanan Ingersoll & Rooney PC, the law firm handling the case, estimate dumping margins as high as 920%. If the investigation proves conclusive, The U.S Department of Commerce will assess the use of additional tariffs equal to the extent of unfair pricing.

So, what does this mean for Australian graphite? According to Novonix, it’s all about fair competition and transparency in the global marketplace — both of which can empower Australia in our move to become more dominant in graphite and establish commercial scale production of graphite materials.

According to CSIRO’s report, the growing demand for graphite, and for diversification in the industry, presents Australia with an opportunity to leverage its deposits and move up the supply chain. Several companies have conducted tests and pilots and plan to vertically integrate from their natural graphite deposits, meaning there are several opportunities for research, development and demonstration (RD&D) across the graphite supply chain to support our burgeoning onshore industry.

Spherical graphite

The process of micronisation and spheronisation, where graphite is mechanically ground into small spherical particles, is used to prepare natura graphite for use as the anode material in LiBs.

Conventionally, milling is used to achieve this. Between each milling step, which can use up to 25 series of mills, the material is sorted to obtain a desired size range, which then advances to the next step. Particles that don’t fall within the specified range are taken through the process again or discarded.

Although this method is mature and equipment is readily available, it still has issues of high energy consumption and waste.

Research initiatives in Australia are aiming to overcome the key challenges of spheronisation. For example, the FBICRC’s “Super Anode” has stated a goal to reduce spheronisation wastage of natural graphite by 30%.

RD&D focus areas

Micronisation and spheronisation

• Improving the yield of the milling process, which is often as low as 35–50%.
• Developing graphite byproducts and exploring various value-added applications.
• Reprocessing of finer particles into particles within battery specifications.
• Improving processing time and electricity consumption.

Purified spherical graphite

Micronised and spheronised graphite need to achieve purity levels of about 99.95% to guarantee high capacity and long lifecycles in LiBs. Purification relies on either hydrometallurgical or pyrometallurgical methods.

Currently, graphite purification is primarily achieved with the hydrofluoric acid method. The use of hydrofluoric acid is highly restricted globally, meaning use of this method is not widespread outside of China.

To avoid the use of hydrofluoric acid and thus mitigate associated health, safety and environmental issues, alternatives are being developed, including high temperature methods, leaching via alternative acids, chlorination and alkali roasting.

RD&D focus areas

Alternative acids

• Reducing reaction times and acid consumption and managing pollution (e.g. use of less aggressive or recyclable reagents).

Alkali-acid method

• Reducing complexity and processing time, lowering costs.
• Optimise energy efficiency, streamline processes, and reduce water consumption.
• Managing the toxic wastes and emissions associated with chemical use.

High temperature methods

• Reducing reaction times and acid consumption and managing pollution (e.g. use of less aggressive or recyclable reagents).

High temperature methods

• Applying advanced modelling to enhance the understanding of reduction chemistry and the dynamics of thermochemical reduction.

Chlorination roasting

• Developing and scaling application of chlorination to natural graphite, reducing reagent consumption, accelerating reaction times, enabling continuous processing.
• Developing mitigation and control measures for corrosivity and expelled gases.

Alkali roasting

• Utilising alternative acids and recycling the waste liquid to reduce the environmental impact of the process.
• Overcoming graphite oxidation loss by further lowering the temperatures required while reacting with sodium hydroxide.

Coated purified spherical graphite

Carbon coating is employed in the graphite supply chain to improve performance of natural graphite anode materials and thus, the performance of lithium batteries.

This is because the carbon layer prevents the formation of an excessive solid electrolyte interface (SEI) during battery cycling, buffers the expansion of the material and improves conductivity.

According to CSIRO, publicly known methods to produce coated spherical graphite include wet chemical processing and dry processes, usually followed by high temperature thermal treatment. Various carbon sources can be used as a coating material in this process.

RD&D focus areas

Coated spherical graphite production

• Optimising the surface uniformity of coated particles, to increase anode durability and performance (e.g. improving control of pitch addition or advancing controllable, thin layer deposition methods).
• Identify and trial alternatives to petroleum and coal by-products that can serve as economically viable carbon sources for coating processes.
• Develop and assess dopants embedded in the coating layer and the coating of composite materials, to explore potential improvements to anode performance.
• Develop the use of coating technologies to reinstate the properties and performance of spent graphite, as part of its recycling process.
• Trial and implement alternatives to hazardous and costly solvents used in some wet chemical processes. This can include replacements that pose lower risk but remain suitable to disperse graphite and the carbon source.

 Silicon-graphite compound materials

Composite materials, consisting of silicon and graphite, are increasingly being used to enhance the performance of lithium-ion batteries combining the high capacity of silicon and the conductivity of carbon, according to CSIRO. Although silicon significantly increases the energy density of batteries, it can cause the SEI to become unstable and degrade the performance of the battery.

According to CSIRO, manufacturers have been delivering breakthroughs in the amounts of silicon incorporated, pushing the boundaries of battery performance. Silicon-graphite composites, where the silicon and graphite sit within a matrix structure, offer a solution to buffer the expansion of the silicon.

This additional application of silicon is unlikely to challenge graphite’s dominant position in the short term, according to the IEA. The IEA says it expects a continued shift towards higher silicon contents over time.

“This trend, coupled with the adoption of alternative anode chemistries such as lithium metal anodes, high silicon anodes (exceeding 50% silicon content) and hard carbon

(used in sodium-ion batteries), gradually affects the pace of graphite demand growth in the longer term, leading to a moderate reduction in graphite demand in batteries post-2040,” the agency said in its report.

“However, the speed of deployment of these alternative chemistries depends on overcoming significant technical and scaling challenges, such as ensuring high cycle life and resisting volume changes.”

RD&D focus areas

General

• Development of material structures and compositions that overcome the limits to silicon content (relating to silicon’s expansion during cycling), and that can be effectively fabricated at scale.

Mechanical methods

• Improving morphology control and uniformity across the composite material.

Wet chemical methods

• Expanding the range of material structures obtained, and other material improvements (e.g. using dopants or additional carbon structures like nanotubes), to increase anode stability and performance.

Spray-based methods

• Improving the thermal efficiency of the process at scale (e.g., heat recovery strategies, or increasing product yield).

Chemical vapour deposition

• Reducing the energy intensity of this process and managing the environmental or safety risks associated with some of the gases that may be used in this method.

 Recycling

While recycling is a promising option for many other critical minerals, the future of graphite recycling is less clear-cut. According to the IEA’s Recycling of Critical Minerals: Strategies to scale up recycling and urban mining, A World Energy Outlook Special Report, while some recycling and reutilisation may exist for other applications of graphite, this has yet to emerge for clean energy applications such as batteries.

Some of this is because recycling of graphite is economically challenging, as graphite has a low value compared to other materials. This means virgin graphite material is more desirable for batteries, as there are no additional costs to the value chain.

Despite this, there is still interest in low-cost recycling methods, suitable for batteries, globally. According to the IEA, Ascend Elements and Koura developed a hydrometallurgical process to produce 99.9% pure graphite exceeding battery-grade requirements and are planning to build a graphite recycling facility in the United States. The IEA also says scientists have recently developed a low-cost method of graphite recycling that has been shown to produce battery performance comparable with cells using virgin material, offering another promising pathway.